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Department of Commerce
FINAL REPORT
DEVELOPMENT O F IMPROVED CORROSAON RESISTANT STAINLESS S T E E L
PROJECT 9 170-4037 CONTRACT DDR- 124
GENERAL ELECTRIC COMPANY, HANFORD
.isrc-- -
W. G. Renshaw
October 23 , 1962
I
Approved by :
R. A . Lula
DISCLAIMER
This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.
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A L L E G H E N Y L U D L U M S T E E L C O R P Brac kenr idge, Pennsylvania
FINAL REPORT
DEVELOPMENT OF IMPROVED CORROSION RESISTANT STAINLESS STEEL
O R A T I O N
GENERAL
In t roduc t ion :
PROJECT 917Qd4837 CONTRACT DDR- 124 ELECTRIC COMPANY, HANFORD
The General E l e c t r i c Company, Hanford Works, has encountered d i f f i c u l t i e s with
p re sen t m a t e r i a l s used f o r s t o r a g e tanks and concen t r a to r s f o r r e a c t i v e waste and .- _.__/------- --- -
r e a c t o r v e s s e l s fo2- d i s s o l v i n g fuel. elements. S ince t h e chemical s o l u t i o n s involved --I _-_. ----------- ---
i n t h e process ing must be h igh ly ‘ co r ros ive t o accomplish t h e i r purpose, co r ros ion
problems f o r handl ing equipment, become s e r i o u s a s wel l . I i p such equipment, bu t leaves much t o be d e s i r e d because of h igh co r ros ion r a t e s ; t h e
Type 304L has been employed
problems a s s o c i a t e d with f a i l u r e and d i sposa l of f a i l e d equipment a r e obvious.
is need f o r a l l o y s wi th improved co r ros ion r e s i s t a n c e .
s t e e l have been i n v e s t i g a t e d a t General E l e c t r i c Company and whi le an improvement,
they do no t f u l f i l l a l l t he d e s i r e d c h a r a c t e r i s t i c s needed.
There
Types 309L and 309Cb s t a i n l e s s
The u s e of n i t r i c - h y d r o f l u o r i c mixtures more r e c e n t l y a s a p r e f e r r e d chemical
process ing s o l u t i o n poses a much more s e r i o u s d i f f i c u l t y , because u n l i k e o t h e r
minera l a c i d s , hydro f luo r i c i s not e a s i l y o r r e a d i l y i n h i b i t e d i n i t s co r ros iveness
and n i t r i c provides l i t t l e , i f any, b e n e f i t toward i n h i b i t i o n .
The purpose of t h i s i n v e s t i g a t i o n has been to’develop new o r improved a l l o y s -- - -- e-
which might be employed i n p rocess ing equipment, and e s p e c i a l l y equipment handl ing -.----- ---_--- __L_.- ----___----------- -------
n i t r i c - h y d r o f l u o r i c a c i d mixtures . - -- -__ .--------
Summary:
S p e c i a l modi f ica t ions of Types 309 and 310 and a l s o higher chromium and n i c k e l 2__4- \ --_ - - .- - - ___.--.
E.*
a l l o y s have been eva lua ted f o r t h e i r a b i l i t y to meet co r ros ion requirements . ---- ~
-\
U Tes t s have been conducted on welded and unwelded samples from 15 spec ia l l abora to ry
Page 2
melted compositions i n b o i l i n g 65% n i t r i c a c i d , i n b o i l i n g 13 molar HNO3 wi th add i -
t i o n s of .075M, 0.25M and 0.50M HF, i n 0 . 5 molar s u l f u r i c a c i d , i n 6% f e r r i c c h l o r i d e
and i n a b o i l i n g mixture con ta in ing 6M HNQa + .4M H2SQ4 + .4M NaN03 -‘i- .3M Fe2(S04)3 +
.OLM C r + . O l M Hg + .Om P04. Welds b.ave been examined a f t e r co r ros ion t e s t s , and
s e n s i t i z e d specimens from a l l compositions have been t e s t e d i n b o i l i n g 65% n i t r i c
a c i d .
Success fu l l abo ra to ry me l t ing and process ing of t h e s e compositions t o p l a t e and
s h e e t has been accomplished on smal l s c a l e equipment. Mul t ipass welding by t h e
manual tungs ten i n e r t gas method us ing f i l l e r s t r i p s c u t from s h e e t was s u c c e s s f u l i n
sample p r e p a r a t i o n wi th no evidence of c rack ing or o the r d i f f i c u l t i e s .
It may be concluded t h a t , i n both t h e n i t r i c - h y d r o f l u o r i c mixtures and t h e
tomplex mixture , a much improved gene ra l co r ros ion r e s i s t a n c e over Type 309 can be /-- /-----J
ob ta ined wi th .02% carbon Type 310 Cb, wi th .02% carbon Type_-3JO, and wi th a l l of
t h e h igh chromium n i c k e l a l l o y s . I n regard t o a t t a c k i n weld h e a t a f f e c t e d zones
t h e s e r e s u l t s show t h e .02% carbon Type 310 Cb t o be oqts tanding . While t h e .02%
carbon Type 310 shows some t r a c e evidence of discont inuous p r e c i p i t a t e a t g r a i n
- --. - -- -_ ...-- - -. ---- -.--_ --- . --. . . -- . . ---’ ‘\_____/ - - . - ,
- -~ ....
boundaries , it s u f f e r e d no i n t e r g r a n u l a r a t t a c k ad jacen t t o t h e weld even i n t h e
b o i l i n g n i t r i c - h y d r o f l u o r i c s o l u t i o n s , bu t d i d e x h i b i t a s l i g h t e t ch i n t h i s a r e a . *
The a u s t e n i t i c 30% C r - 25% Ni a l l o y which w a s very e x c e l l e n t i n genera l cor ros ion
r e s i s t a n c e , un fo r tuna te ly s u f f e r e d i n t e r g r a n u l a r a t t a c k i n t h e h e a t a f f e c t e d zone
b u t t h i s may be a t t r i b u t e d t o t h e h igh n i t rogen con ten t ( .084%).
/ __- -
’ \/-~-.u--
F ,
There i s cons ide rab le v a r i a t i o n i n s e n s i t i v i t y of t h e 65% n i t r i c a c i d , t h e
HN03-HF, and t h e complex mixture t o g r a i n boundary p r e c i p i t a t e s o r o t h e r s t r u c t u r a l
cond i t ions . I n t h e course of sample examination i t was d iscovered t h a t t h e complex
s o l u t i o n can cause a u s t e n i t e g r a i n boundary e t ch ing even i n the absence of a v i s i b l e
p r e c i p i t a t e . S i m i l a r l y t h e n i t r i c - h y d r o f l u o r i c s o l u t i o n s s e v e r e l y a t t a c k t h e Type
309 Cb weld s t r u c t u r e but a r e very mild toward Type 310 o r Type 310Cb.
understood about why t h e s e s o l u t i o n s behave a s they do.
Much i s not
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Recomrnenda t ion :
Based on t h e s p e c i f i c compositions included i n t h i s i n v e s t i g a t i o n , t h e .02%
carbon Type 310 Cb (Heat GD-44) appears most promising as an improvement over Type
309L and Type 309Cb. It possesses improved genera l c o r r o s i o n r e s i s t a n c e i n b o i l i n g
"03-HF s o l u t i o n s and i n t h e b o i l i n g complex mixture and, fur thermore, shows no i n t e r -
g ranular s u s c e p t i b i l i t y o r a c c e l e r a t e d a t t a c k i n h e a t a f f e c t e d weld zones nor does t h e
weld s u f f e r s eve re d i s i n t e g r a t i o n i n e i t h e r s o l u t i o n . A second a l l o y posses s ing
nea r ly a s good p r o p e r t i e s (Heat FV-19A) is a .02% carbon Type 310. On a l abora to ry
s c a l e i t has a l s o been demonstrated t h a t t h e s e Type 310 compositions can be success-
f u l l y mel ted and processed t o p l a t e and s h e e t , and welded wi th no cracking.. Provided
t h e improvements i n co r ros ion r e s i s t a n c e a r e a t t r a c t i v e t o General E l e c t r i c Company,
Hanford, t h e second phase c o n s i s t i n g of t h e development of product ion methods f o r m i l l
s i z e d h e a t s i n s h e e t , p l a t e and tub ing should be undertaken.
Should even a g r e a t e r improvement i n co r ros ion r e s i s t a n c e be d e s i r e d t h e h ighe r
chromium and n i c k e l a l l o y s warrant a d d i t i o n a l i n v e s t i g a t i o n . S ince each of t h e four
d i f f e r e n t C r - N i compositions were r e s t r i c t e d t o a s p e c i f i c carbon and n i t r o g e n con-
t e n t , a program t o s tudy t h e in f luence of t h e s e l a t t e r two elements would be necessary
be fo re they could be recommended. The f u l l y a u s t e n i t i c Heat FV11, a 30 C r - 25 N i
a l l o y , would have deserved recommendation were it not f o r i t s s u s c e p t i b i l i t y t o i n t e r -
g ranular co r ros ion .
Add i t iona l s tudy of t h e p e c u l i a r e f f e c t s of s e n s i t i z i n g on c o r r o s i o n by t h e
HN03-HF and complex s o l u t i o n is ind ica t ed . The unusual a u s t e n i t e g r a i n boundary e t c h
by t h e complex s o l u t i o n even i n the' absence of v i s i b l e p r e c i p i t a t e d ca rb ides i s
unexplained, and equa l ly myster ious i s t h e s l i g h t a c c e l e r a t i o n of HNO3-HF a t t a c k a t
a r e a s where only a t r a c e discont inuous g r a i n boundary p r e c i p i t a t e is p r e s e n t .
A 1 loy Compos i t ion S e l e c t ion :
I n a development program of t h e type involved h e r e i t was necessary t o cons ider / \
s e r i o u s l y t h e problem of i n t e r g r a n u l a r s u s c e p t i b i l i t y i n t h e a s welded c o n d i t i o n s i n c e
Page 4
t h e na tu re and s i z e of t h e equipment involved does not permit a pos t -annea l ing opera-
t i o n . For t h i s reason a l l h e a t s were melted with t h i s i n mind and low carbon o r
columbium s t a b i l i z a t i o n was employed t o accomplish t h i s . Vacuum mel t ing of ve ry low
carbon v a r i a t i o n s of t h e Type 309 composition below .03% was o f f e r e d a s one s p e c i a l
v a r i a t i o n . The a d d i t i o n of columbium t o low carbon Type 310 was another .
The p u r i t y of m a t e r i a l s was cons idered a s poss ib ly a f f e c t i n g t h e gene ra l co r ro -
s i o n r e s i s t a n c e i n these environments and t h e use of h igh and low s i l i c o n modi.fica-
t i o n s of Type 310 a s we l l a s high and low manganese con ten t i n Type 310 was proposed
a s worthy of i n v e s t i g a t i n g .
F i n a l l y t h e s e l e c t i o n of h igher chromium and n i c k e l a l l o y s above t h e s t anda rd
S t a i n l e s s s t e e l ranges would be expected t o provide . . b e t t e r co r ros ion r e s i s t a n c e
because of t h e i r a l l o y con ten t . These a l l o y s could, t h e r e f o r e , s e r v e a t.wo f o l d
purpose because i t i s gene ra l ly known t h a t p r e c i p i t a t i o n of harmful i n t e r g r a n u l a r
ca rb ides i s f r e q u e n t l y r e t a r d e d apprec iab ly i n a duplex a u s t e n i t i c f e r r i t i c s t r u c -
t u r e .
Table I covers t h e composition aims which were s e l e c t e d t o be melted i n t h e
program. These were 100 pound a i r induct ion and 50 pound vacuum induct ion l abora to ry
h e a t s . The r equ i r ed method of me l t ing i s des igna ted i n t h e t a b l e , s i n c e those
m a t e r i a l s wi th ve ry low carbon n e c e s s i t a t e d vacuum mel t ing .
have to be cons idered as a product ion method i f i t were found t h a t t h e s e compositions
Vacuum mel t ing would
E
had t h e b e s t performance i n t h e co r ros ion tests.
. TABLE &
COMPOS I T I O N OF LABORATORY
AIM
S i z e of Method of
HEATS
U I t e m 11 Heat Melt inp C ---- Mn S i C r N i P S Cb
1 loo# A i r Ind. .03 max .75 .35 35 23 .045 max .03 max - 2 loo# A i r Ind. .03 max .75 .35 30 20 .045 max .03 max - 3 l O O # A i r Ind. .03 max .75 .35 30 25 .045 max .03 max -
---
iJ --.
TABLE I (contd)
S i z e of Method of
pehpcI9c..- em # Heat M e l f i n L A L A L 6 r N i 4 5
6
- 7 8 9 10 11 1 2 13 14
15
loo# 50# 50# 5 O# 50#
loo# loo# loo# .508 50# 5 O# 50#
loo#
A i r Ind. A i r Ind.
A i r Ind.
Air-50# A i r - 5 O V A i r Ind. Vacuum Vacuum Vacuum Vacuum A i r Ind.
( a )
(b )
l O O # A i r Ind .
.03 max
.03 max
.03 max
.03 max
.03 max
.03 max
.03 max
.03 max
.01 max
.005 max
.001 max
.01 max
.05 max
.02 max
.75
.10 1.00 . 75 . 75
.75
.75 1 .50 1.50 1.50 1 .50
.50 1.50
.75
Page 5
p s - -L ..35 30 15 .045 max .35 25 20 .045 max .35 25 20 ,045 max .30 25 20 .045 max
1.00 25 20 .045 max 0 25 20 .045 max
.15 25 20 .045 max
.40 22.25 14.50 - * . 4 0 22.25 14.50 -
.40 22.25 14 .50 -
.40 22.25 14 .50 -
.40 22.25 15.25 -
.40 22.50 14.50 - - 3 5 25 20 -
.03 max
.03 max
. 03 max
.03 max
.03 max
.03 max
.03 max
- - - - - . -
(a') (b)
Pour 50 l b . i ngo t and then add 1% Mn t o remaining 50# p o r t i o n Pour 50 l b . ingot and then add 1% S i t o remaining 50# p o r t i o n
I n r e s p e c t t o s t r u c t u r e , t h e proposed compositions were c l a s s i f - i e d i n t o two
groups: duplex s t r u c t u r e . a u s t e n i t i c - f e r r i t i c h e a t s and f u l l y a u s t e n i t i c h e a t s .
Heat numbers 1, 2 , 3 , and 4 (Table I) show t h e composition of t h e proposed duplex
s t r u c t u r e m a t e r i a l s . The main advantage of t h e s e h e a t s i s t h e i r r e s i s t a n c e t o i n t e r -
g ranular co r ros ion . I n h igh ly a l loyed a u s t e n i t i c s t a in l ' e s s s t e e l s t h e s o l u b i l i t y f o r
carbon decreases , and even hold ing t o .03% max carbon con ten t does not seem to be
s u f f i c i e n t t o i n s u r e good r e s i s t a n c e t o i n t e r g r a n u l a r a t t a c k . While. lower carbon
con ten t below .03% would be h e l p f u l , t h i s r e q u i r e s , s p e c i a l me l t ing procedures which
a r e more expensive and t h e r e is a l s o a l i m i t a t i o n i n t h e s i z e of such h e a t s . I n con-
t r a s t t h e duplex s t r u c t u i e m a t e r i a l s a r e r e s i s t a n t t o i n t e r g r a n u l a r a t t a c k a t " 03%
carbon o r even h igher . These f e r r i t e - a u s t e n i t e compositions have, i n gene ra l , h igher
mechanical p r o p e r t i e s , though t h i s might not be an important f a c t o r i n t h e s e l e c t i o n
of a m a t e r i a l . S ince chromium i s t h e most impoftant element i n c o n f e r r i n g c o r r o s i o n
r e s i s t a n c e i n t h e media involved here , i nc reas ing t h e chromium con ten t thus produced
t h e s e duplex , s t r u c t u r e s . The presence of d e l t a f e r r i t e , per s e , does no t adve r se ly
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a f f e c t co r ros ion r e s i s t a n c e except i n c a s e s where it might l ead t o t h e formation O f
sigma phase. Sigma phase may b e hazardous t o n i t r i c a c i d co r ros ion r e s i s t a n c e . The
n i c k e l conecjtit of the duplex phase W B I var%ad fn erder t e eetablish its i n f luenee in
t h e s e s t r o n g n i t r i c a c i d s o l u t i o n s , and a l s o t o e s t a b l i s h i f i t can c o n t r o l e m b r i t t l e -
ment i n t h e weld.
The a u s t e n i t i c h e a t s were designed t o i n v e s t i g a t e s e v e r a l co r ros ion problems.
Heat number 5 (Table I) was a 25% chromium, 20% n i c k e l h e a t which was d iv ided
i n t o two 50-pound ingo t s of i d e n t i c a l composition wi th t h e except ion of manganese
which was aimed a t . lo% i n one ingot and 1% i n t h e o t h e r . The o b j e c t of t h i s was t o
i n v e s t i g a t e t h e i n f l u e n c e of manganese i n t h e co r ros ion problems. There a r e no da ta
i n t h e l i t e r a t u r e t o r e v e a l t h e in f luence of manganese a t t h i s l e v e l , and i t i s I g ene ra l ly assumed t h a t i t does not a f f e c t co r ros ion r e s i s t a n c e i n t h i s 1ow.range. We
e a r l i e r e s t a b l i s h e d experimental ly i n our l abora to ry t h a t v a r i a t i o n of manganese
con ten t i n t h i s range had n o t i c e a b l e in f luence on the ox ida t ion p r o p e r t i e s .
ox ida t ion and co r ros ion r e s i s t a n c e a r e no t n e c e s s a r i l y r e l a t e d , ox ida t ion du r ing
annea l ing might i n f luence t h e base meta l ad jacen t t o t h e oxid ized s u r f a c e and was
subsequent ly , f o r t h i s reason, considered necessary t o i n v e s t i g a t e .
W h i l e
Heat numbers 6, 7 , and 8 represented 25% chromium and 20% n i c k e l s t e e l s wi th
va r ious s i l i c o n con ten t s .
composition except s i l i c o n con ten t .
chromium - 20% n i c k e l with 0 and .15% s i l i c o n .
i n t e r e s t s i n c e it i s impossible p r e s e n t l y t o produce a commercial a i r mel ted h e a t
with s i l i c o n con ten t lower than .20%. It has been e s t a b l i s h e d t h a t s i l i c o n has an
in f luence on t h e co r ros ion r e s i s t a n c e of a u s t e n i t i c s t a i n l e s s s t e e l s . This was
r epor t ed by Brown, DeLong and Myers*, as wel l a s by Bur ra t .
Heat number 6 was d iv ided i n t o two ingo t s wi th i d e n t i c a l
Numbers 7 and 8 a r e 50-pound h e a t s of 25%
This information was only of academic
Heat numbers 9 , 10, 11, 1 2 , and 13 were Type 309L i n which t h e carbon con ten t
was decreased from . 03 t o ,001 i n order t o e s t a b l i s h t h e l i m i t of s o l u b i l i t y f o r
carbon and carbon l e v e l necessary t o prevent i n t e r g r a n u l a r co r ros ion .
7kASTM S p e c i a l Technica l Pub l i ca t ion No. 165
Page 7
Heat number 14 was Type 309Cb, included f o r comparison wi th o t h e r m a t e r i a l s and
f o r t h e s tudy of k n i f e - l i n e a t t a c k .
Heat number 15 was s e l e c t e d because based on e x i s t i n g publ i shed informat ion
and gene ra l c o n s i d e r a t i o n of t h e co r ros ion and m e t a l l u r g i c a l problems t h i s was t h e
optimum a n t i c i p a t e d composition.
Melt inP and Actual Compositions At t a ined :
I n gene ra l , wi th a few except ions , i t was p o s s i b l e t o a t t a i n t h e d e s i r e d composi-
t i o n a s shown i n Table 11. The composition des igna ted item 1 2 was cance l l ed , however,
because i t was impossible t o a t t a i n t h e d e s i r e d .001% carbon by vacuum induct ion
mel t ing . Heats FV7l-15 and FV70-15 were remade h e a t s u s ing Gra ina l 7 9 , ( l ) s i n c e t h e
o r i g i n a l h e a t s cracked dur ing hot r o l l i n g . Both t h e s e h e a t s have t h e h ighes t d e l t a I
f e r r i t e s t r u c t u r e . I n t h e c a s e of Heat FV56-15, t h e s i l i c o n con ten t was he ld a s low
a s p o s s i b l e t o .033%, but i n order t o do t h i s t h e raw m a t e r i a l s were of such p u r i t y
t h a t carbon con ten t became unusual ly low, .0039%, cons ide r ing t h e .03% maximum carbon
aim. I n t h e fol lowing h e a t , FV57-15, t h e s i l i c o n con ten t of .28% is somewhat h igher
t han t h e aim of .15%. The f a c t t h a t i t l i e s between 0 and the usua l - 4 % average
poin ted t o our dec i s ion t o t e s t t h i s anyhow, s i n c e i t could f i l l t h e gap and main ta in
a reasonable carbon con ten t .
(1)
p r o p e r t i e s : Improves ho t working c h a r a c t e r i s t i c s of wrought s t a i n l e s s s t e e l s and
reduces hea t checking of c a s t i n g s . .The c h i e f advantage of t h e use of Gra ina l 79
i n our work h e r e has been t o avoid c rack ing of t hese h igh a l l o y con ten t s t a i n l e s s
s t e e l s dur ing h o t r o l l i n g . Gra ina l 79 i s manufactured by Vanadium Corpora t ion of
America and has t h e fol lowing chemical composition:
Gra ina l 79 i s an a d d i t i o n f o r f e r rous me l t s which can impart the fo l lowing
c u - B - - C - Mn - Z r - S i A 1 T i
. 1 7 7 . 6 7 . 2 . 8 7 3.24 12.49 21.67 .50 .22
n
n mJ ]! TABLE I1 --
- ACTUAL COMPOSITIONS
Method of Item # Heat No, Melt ing C Mn S i C r N i P - Cb T i Cu Co A 1 N
*1
2
3
*4
5
6
7
8
9
10
11
FV71-15 A i r Ind. .030 .86 .39 34.74 19.70 .024 .017 - .025 .070 .028 - 004 2 -066
N20-15 A i r Ind. .022 . 8 7 .51 30.28 19.83 .008 .010 - .018 .040 .044 -0031 -060
FV11-A A i r Ind. .030 .83 .56 30.32 24.48 .015 .011 - .011 .050 .056 .0017 .084
FV70-15 A i r Ind . ,024 .75 .42
FV17-15A A i r Ind. .017 .33 .52 FV17-15B A i r Ind. .018 1.24 .48
29.96 15.14 .025 .019 - .025 .070 ,053 - 00 30 -037
25.48 20.28 25.36 20.13
.020 .016 - .018 .080 ,058
.015 .016 - .011 .082 .052 .0022 -0026
.048 -046
FV19-15A A i r Ind. -020 .85 .47 FV19-15B A i r Ind. .017 . 8 2 1.07
25.62 20.30 25.18 20 .2 i
.015 .008 - .014 .082 .062
.015 . O M - ,011 .080 .062 .GI013 -0071
.047 -046
FV56-15 A i r Ind. .0039 . 7 7 .033 24.40 19.99 .006 .014 - .014 .030 ,045 -0025 .040
FV57-15 A i r Ind. .021 .90 .28
FY78-14 A i r Ind. .026 1.59 .45
24.80 19.61 .008 ,014 - .011 .030 .069 ,0039 .045
22.25 14.25 .022 -_ ,015 - .014 .035 .039 .0031 .030
RV296-4 Vacuum .-, ,0086 1.51 .42 22.34 14.51 . Q O 8 .010 - .022 .030 .034
.008 .008 - .011 .035 .057
.QO27 -0028
RV294-4 Vacuum .0041 1.57 .46 2 2 . 7 1 14.32 .QQ29 -0044
13
14
15
RV297-4 Vacuum .0081 .59 .45 22.30 15.03 .008 .008 - .014 .030 .031 -0024 .0038
FY79-14 A i r Ind. .043 1.53 .47 22.48 14.25 .015 .013 .40 .014 .042 .034 .0015 .044
. 0 4 3 ' P, 00
03 GD-44 A i r Ind. ,015 .84 .40 24.76 , 20.00 .014 ,015 . 2 2 .014 .057 .035 .0022
q h e s e two hea t s were melted with 4#/ton r a t i o of Grainal 79. O r i g i n a l hea t s cracked seve re ly and had t o be remade.
Page 9
It is s i g n i f i c a n t t o no te t h a t , a l though no aim was made on n i t r o g e n con ten t ,
t h e vacuum melted h e a t s , RV-294, RV296, and RV297, have ve ry low n i t rogen compared
t o t h e usua l normal con ten t of about .04%. On t h e o t h e r hand, t h r e e of t h e v e r y h i g h
C r - N i a l l o y s had s l i g h t l y higher than normal n i t rogen , due t o t h e f a c t t h a t i t i s
added a s a p a r t o f t h e ferrochrome add i t ion . This was of some concern, s i n c e n i t r o -
gen may appear i n a g r a i n boundary n i t r i d e p r e c i p i t a t e s i m i l a r t o c a r b i d e when h igh
n i t rogen s t a i n l e s s s t e e l s a r e s e n s i t i z e d . This i s d iscussed l a t e r i n t h e i n s t a n c e
of Heat FV-11 with .084% N .
Unlike commercial h e a t s , impur i t i e s and n o n m e t a l l i c i nc lus ions a r e more common
i n smal l r e sea rch h e a t s . This f a c t i s o f t e n evidenced a s end g r a i n a t t a c k on heavy
gage co r ros ion t e s t samples; t h i n gage s h e e t i s not . sub jec t t o end g r a i n a t t a c k .
Thus s h e e t samples a r e p r e f e r r e d to e s t a b l i s h co r ros ion ' rates.
Process ing t o Gage :
M a t e r i a l from a l l h e a t s was condi t ioned , forged t o shee t bar and then hot r o l l e d
t o 1/4" p l a t e ( f o r weld t e s t samples). Enough m a t e r i a l was s e l e c t e d a t t h i s s t a g e
f o r t he purpose of provid ing welds, and t h e remaining approximate 40% of each h e a t
was f u r t h e r processed e i t h e r by hot r o l l i n g t o . loo" o r .060" or by hot r o l l i n g t o
. l oo" and subsequent co ld r o l l i n g t o .060".
No d i f f i c u l t i e s were encountered i n process ing any of t h e h e a t s a t any s t a g e s .
The two h e a t s mentioned previous ly , which were remelted u s i n g Gra ina l 79, a l s o pro-
cessed s a t i s f a c t o r i l y wi th no c racking .
f o r a l l h e a t s a r e r epor t ed i n Table 111.
\
i I
The fo rg ing and ho t r o l l i n g temperatures
It i s poin ted out t h a t l abo ra to ry process ing on t h i s smal l s c a l e cannot dup l i -
c a t e commercial ho t f i n i s h i n g p r a c t i c e s .
many times l a r g e r than a l abora to ry ingot , much g r e a t e r r educ t ions a r e necessary t o
S ince t h e s t a r t i n g commercial i ngo t i s
reach t h e gages involved i n t h i s program. Thus g ra in ref inement and uni formi ty of
s t r u c t u r e i n our 1/4" p l a t e tes t samples i s much l e s s than would be a t t a i n e d i n an
Page 10
a c t u a l m i l l product . However, t h e information gained from our p rocess i cg methods i s
h igh ly s i g n i f i c a n t , f o r it i n d i c a t e s t h a t with development of s u i t a b l e m i l l p rocess ing
procedures a l l of the e e m p e s i t i o ~ s a r e probably capable of s a t i s f a c t o r y product ion on
a l a r g e s c a l e .
TABLE 111
PROCESSING DATA
--
Forged t o Sheet Hot Rolled t o Hot Rol led to Cold Rolled t o - Item # Heat No. Bar a t .25" a t * Gage Temp.
1 2 3 4 5
I
6
7 . 8 . 9 10 11 13 14 15
F v 7 1 Fi20 W l l FV 70 FV 17 - 15A E'V 17 - 15B FV19-15A FV 19 - 1 5B FV56 Fv57 FY78 RV296 RV294 RV29 7 FY79 GD44
2200°F 2200°F 2200°F 2200°F 2200°F 2200°F
2200°F 2200°F 2200°F 2200°F 2200°F 2200°F 2200°F 2200°F 2200°F 2200°F
2100°F 2103°F 2100°F 2100°F 2100°F 2,100"F ,
2100°F 2100°F 2100°F 2100°F 2150°F 2150°F 2150°F 2150°F 2150°F 2100°F
.060" 2100°F
.0601' 2100°F
.060" 2100°F ,
,060" 2100°F .060" 2100'F
used f o r . weld f i l l e r .060" 2100°F .060" 2100°F - - - - . loo" 2150°F . 100" 2150°F . l oo" 2150°F ,100" 2150°F . loo" 2150°F . loo" 2100°F
* M a t e r i a l taken a t t h i s gage subsequent ly was annealed a t 2050°F and used f o r weld t e s t s . Samples t e s t e d as welded only, except f o r a few s p e c i a l samples reannealed and then s e n s i t i z e d a t 1200°F.
Annealing and Descalinq:
The p l a t e m a t e r i a l a t 1/4" rece ived an a n n e a l p a t 2050°F f o r 20 minutes , a i r
cooled, followed by desca l ing i n 15% "03 + 3% HF.solu t ion .
quen t ly welded and co r ros ion t e s t e d i n t h e as welded condi t ion .
This m a t e r i a l was aubse-
The p o r t i o n s of each hea t t h a t were hot r o l l e d t o l i g h t e r gages were desca led i n
15% "03 + 3% HF a t var ious s t a g e s and b e f o r e co ld r o l l i n g .
m a t e r i a l s were degreased i n 10% a l k a l i n e c l e a n e r of t h e sodium o r t h o s i l i c a t e t ype and
then annealed a t t h r e e temperatures (2050"F, 2150°F and 2300°F) s i n c e it was f e l t t h a t
annea l ing temperature might have an in f luence on co r ros ion . r a t e s , e s p e c i a l l y where
A f t e r c o l d r o l l i n g all
Page 11
duplex a u s t e n i t i c - f e r r i t i c s t r u c t u r e s a r e p re sen t i n t h e base m a t e r i a l . This informa-
t i o n would a l s o be inva luab le f o r subsequent m i l l processirig a s s i s t a n c e . A l l .060"
s h e e t m a t e r i a l s r ece ived an annea l of 15 minutes , a i r cool , followed by p i c k l i n g i n
15% "03 - 3% HF at 140'F t o d e s c a l e them i n p repa ra t ion f o r c o r r o s i o n t e s t s .
S t r i p s .060" x 3/16" were sheared from Heats FV17B, GD44, N78, RV294, RV296,
RV297, and FY79 f o r f i l l e r meta l i n welding.
We ld inq :
The 1/4" p l a t e s e c t i o n s which were annealed a t 2050'F were c u t i n t o 24" long
s t r i p s and machined t o a s i n g l e V-groove p repa ra t ion wi th a 60' included ang le .
Mul t i -pass welding by t h e manual t ungs t en i n e r t gas method was employed, u s i n g f i l l e r
p e t a l of sheared s t r i p s of s h e e t .
p rovides t y p i c a l s t r u c t u r a l e f f e c t s i n t h e base meta l and weld t h a t would. e x i s t i n
process v e s s e l s and equipment A s u r f a c e c r o s s weld pass was subsequent ly app l i ed t o
Mul t ipass welding which involves h ighe r h e a t input
permit eva lua t ion of t he cond i t ion which would occur i n a c t u a l f a b r i c a t e d s t r u c t u r e s .
F i l l e r meta ls employed i n welding were s t r i p s c u t from s h e e t as fo l lows:
A l l Type 309 compositions were welded wi th f i l l e r s t r i p s c u t from each i n d i v i d u a l ( a )
h e a t .
s i t i o n .
This was a l s o t r u e f o r Heat GD44, t he .02% carbon Type 310 p l u s Cb compo-
( b ) A l l remaining h e a t s used f i l l e r meta l from Heat FV17B, a .02% carbon Type 310.
Table I V shows t h e r e s u l t s of magne-gage readings f o r t h e base m e t a l , a f u s i o n
c r o s s weld, and of t he weld wi th f i l l e r added.
and r e v e a l s a n i n t e r e s t i n g observa t ion t h a t t h e expected duplex s t r u c t u r e f o r Heat
Th i s i s a measure of f e r r i t e con ten t ,
FVll ( a 30 Cr-25 N i hea t ) d i d not m a t e r i a l i z e . Th i s may be due t o t h e f a c t t h i s h e a t
contained .084% ni t rogen , a s t r o n g a u s t e n i t i z e r . The t h r e e vacuum Type 309 h e a t s
with ve ry low carbon and n i t rogen showed some f e r r i t e i n t h e base metal as annealed
a t 2050'F and some i n c r e a s e a f t e r welding.
from t h e f e r r i t e s t andpo in t upon welding. A s expected, t h e high chromium-nickel
a l l o y s show high d e l t a f e r r i t e con ten t s , i nc reas ing when they a r e f u s i o n welded.
None of t h e 25-20 h e a t s were a f f e c t e d
Heat No.
W71
Fv20
Fvll
FV 70
Fv17A
' W17B
Fv 19A
J?V 19B
FV56
FV57
GD44
m 7 a
RV294
RV296
RV29 7
FY79
-.- TABLE - I V
MAGNE-GAGE READINGS
% MAGNETIC PHASE
Annealed @ 2050°F + Welded
Base Metal Analysis
35-20
30-20
30-25
30-15
25-20 + .33 Mn
25-20 w i t h .018 C
25-20 wi th .020 C
25-20 -k 1 S i
25-20 wi th .03 S i
25-20 wi th .28 S i
25-20 Cb
Type 309L
Type 309-very low C
Type 309-very low C i
Type 309-very low C
Type 309 Cb
Base Metal Fusion Weld
18%
12
0
22
0
0
0
0
0
0
0
1
4
3
2
5%
2 7%
12
0
40
0
0 '
0
0
0
0
0
2
I 7
P
6
3
5%
Page 1 2
FV17B F i l l e r Metal
11%
8
0
18 :
0
0
0
- 0
0
0 (.GD44)
. 7 (RV294)
5 (RV296) ,
3 , (RV29 7)
5% (J379)
. I
Page 13
Afte r welding, a l l samples were mechanical ly abraded with a l e a f gr inder
a b r a s i v e b e l t wheel t o remove s c a l e and oxides , then l i g h t l y p ick led i n a d i l u t e
hydrochlor ic a c i d s o l u t i o n (chosen because i t avoids i n t e r g r a n u l a r a t t a c k ) . The
welds were not ground f l u s h wi th t h e s u r f a c e , and i n s t e a d t h e l i g h t p repa ra t ion
desc r ibed above l e f t t h e normal contour of t he weld untouched. Subsequently t h e s e
samples were sawed t o a rough s i z e and edges machined t o dimensions f o r co r ros ion
t e s t s .
t e s t s o l u t i o n s .
Sample P repa ra t ion :
A 1/4" ho le was d r i l l e d a t one end t o suspend t h e samples intended for b o i l i n g
Examination of samples a f t e r co r ros ion t e s t i n g i s d iscussed l a t e r .
The weld samples were prepared a s descr ibed above and the edges ground wi th 120
g r i t emery p r i o r t o t e s t i n g . These were then thorovghly degreased i n a ho t 10% I
a l k a l i n e s o l u t i o n of t h e sodium o r t h o s i l i c a t e type, r i n s e d with h o t d i lu t , e n i t r i c
then d i s t i l l e d water and d r i e d be fo re weighing.
The unwelded s a m p l e s were c u t t o ' s i z e a f t e r anneal ing, and a 1/4" ho le d r i l l e d
i n one end of t h e 1" x 2" s i z e . Af t e r deburr ing each sample was ground on t h e s u r f a c e
and edges with 120 g r i t emery, degreased and then pass iva ted in warm 20% HNO3 s o l u t i o n
t o c l e a n and p a s s i v a t e them be fo re weighing.
I, I
The s p e c i a l s e n s i t i z e d samples prepared f o r t h e b o i l i n g 65% n i t r i c a c i d t es t
were hea ted 1 hour a t 1200'F and then l i g h t l y ground and p i ck led i n d i l u t e (20%)
HC1 s o l u t i o n t o remove a l l oxide scale b e f o r e weighing and t e s t i n g .
The s tandard s i z e samples f o r each environment a r e shown below:
(b) HN03-HF s o l u t i o n - 1" x 2" with 1/4 h o l e a t one end
( c ) Complex mixture - 1" x 2" with 1/4 h o l e a t one end
( d ) 65% "03 - 1" x 2" with 1/4 h o l e a t one'end
( e ) .5M H2S04 - 2" 211
( f ) 6% FeCl3 - 4" x 4"
Page 14
Corrosion T e s t s :
(a)
Xn meat; G Q X ~ O ~ ~ O ~ t e o t preglrams fer new &;bloyo, eelectief\ of prapar and rapre-
General Nature of Corros ion Tes t Environments
s e n t a t i v e s o l u t i o n s is o f t e n very d i f f i c u l t . However, i n t h i s program, we were bene-
f i t t e d by previous experience and knowledge of c e r t a i n process s o l u t i o n s t h a t could
be adapted d i r e c t l y t o t h e program. Two of t h e s e s o l u t i o n s a r e descr ibed i n (b ) and
( c ) below. The t h r e e a d d i t i o n a l s o l u t i o n s ( d ) , ( e ) and (f), a r e commonly used t o
e s t a b l i s h gene ra l knowledge of c o r r o s i o n p r o p e r t i e s of t h e s t a i n l e s s s t e e l s .
(b) 1 3 M "03 + .075M HF a t b o i l i n g 1 3 M H N O 3 + .25M HF a t b o i l i n g 1 3 M HNO? + . 50M HF a t b o i l i n g
N i t r i c a c i d cannot i n h i b i t HF except t o a minor e x t e n t . The r a t i o of "0.3 t o HF l is 4 0 : l on a molar b a s i s , bu t should r ep resen t very seve re cond i t ions where a l l o y
composition can be s i g n i f i c a n t .
l a r a t t a c k e s p e c i a l l y we l l i f t h e s e s u s c e p t i b l e cond i t ions e x i s t i n t h e me ta l .
This s o l u t i o n can develop k n i f e - l i n e and in t e rg ranu-
Increased chromium and n i c k e l o f f e r some advantage t o r e s i s t a t t a c k of t h e meta l
( f u l l y annealed o r i n t h e absence of p r e c i p i t a t e d c a r b i d e s ) .
o f t e n be expected i n t h i s environment.
End g r a i n a t t a c k may
These t e s t s must be conducted i n s p e c i a l equipment because of t h e HF con ten t .
F igure I is a photograph af t h e t es t equipment. A polye thylene r e f l u x tube surrounded
by a g l a s s j a c k e t was i n s e r t e d i n t h e top of t h e Kel-F b o t t l e . Cool ing water was
c i r c u l a t e d through t h e j a c k e t . The samples were suspended by means of knot ted Tef lon
t a p e . The v e s s e l was hea ted t o b o i l i n g by immersion i n a h o t o i l ba th . Ke l -F ,vesse l s
were used i n t h i s case .
t u r e .
Length of the t e s t was s i x 24 hour per iods a t b o i l i n g tempera-
Specimens 1" x 2" of unwelded material were employed f o r weight loss determina-
t i o n s a f t e r va r ious hea t t rea tments a t 2050, 2150 and 2300°F.
examined v i s u a l l y and microscopica l ly a f t e r t h e t e s t t o determine ex ten t of i n t e rg ranu-
lar co r ros ion .
c r o s s s e c t i o n .
Welded samples a r e
Samples were stopped be fo re s i x per iods i f co r ros ion a t t a c k pene t r a t ed
- .- - -- - _- -- .
P
i
qJ
-D ..-
la
0 i !
F i l m G920 A p p r o x . 1/2 Size
FIGURE 1
Kel-F Vessel and Polyethylene Ref lux Condenser Used for Boiling Tests in 1% HNO3 + .075, 0.25 and 0.50 M HF
Page 15
. ( c ) 6M "03 + . 4 M H2S04 + . 4 M NaN03 + . 3 M Fe2(S04)3 + . 0 1 M CrS6 + . O l M Hg + .Om PO4 a t b o i l i n g (108OC) - Complex So lu t ion
Although t h e r e a r e o t h e r a c i d s and s a l t s added, t h i s is p r i m a r i l y s t i l l a s t r o n g
ox id iz ing environment because of t 'he high ( 6 M ) n i t r i c a c i d con ten t . The s u l f u r i c
a c i d is approximately 4% by weight, bu t f o r t u n a t e l y i t s e f f e c t i s n u l l i f i e d b;y t h e
s t r o n g i n h i b i t i n g a c t i o n of both t h e n i t r i c a c i d and f e r r i c s u l f a t e . S i m i l a r l y ,
phosphate ion w i l l have no c o r r o s i v e e f f e c t under such s t r o n g l y ox id iz ing cond i t ions .
Sodium n i t r a t e per s e does not cause o r i n h i b i t co r ros ion t o s t a i n l e s s s t e e l s . , While
t h e in f luence of mercury has never been def ined , i t i s d e f i n i t e l y known th'at hexavalent
C r ion i s s t r o n g l y a c c e l e r a t i n g t o n i t r i c a c i d a t t a c k e s p e c i a l l y i n t h e range named
(.01M).
It i s concluded t h a t t h i s test: i s p r i m a r i l y a b o i l i n g 6M n i t r i c a c i d tes t . s t r o n g l y
a f f e c t e d by t h e a c c e l e r a t i n g Cr+6 ion .
chromium con ten t i s a b e n e f i c i a l c o n s t i t u e n t .
For a l l o y s t o r e s i s t t h i s environment, h igher
The t e s t s were conducted i n co ld f i n g e r r e f l u x condensers a t b o i l i n g tempera-
t u r e . Time pe r iod f o r t h i s t e s t was 240 hours , wi th specimens weighed and l o s s e s
c a l c u l a t e d ( inches p e n e t r a t i o n p e r month) each 24 hours . This i s d e s i r a b l e s i n c e
t h e a c c e l e r a t i n g e f f e c t of accumulating chromium Cr+6 ion can be s tud ied .
remembered t h a t t h e r a t i o of s o l u t i o n volume t o specimen a r e a (approximately 150
It must be
m l / s q inch) i n our t es t would no t exis t i n a c t u a l 'equipment i n s e r v i c e , e s p e c i a l l y
never i n h e a t exchanger tubes .
Weld samples were examined v i s u a l l y and mic roscop ica l ly a f t e r tes ts f o r ev i -
dence of i n t e r g r a n u l a r or o t h e r l o c a l i z e d a t t a c k .
(d ) B o i l i n g 65% N i t r i c Acid
Nitr ic a c i d is s t r o n g l y ox id iz ing , so much so t h a t i t does not even a t t a c k
mild s t e e l a t low temperatures . A t b o i l i n g , 18-8 s t a i n l e s s s t e e l may show c o r r o s i o n
r a t e s of perhaps .7 t o 1 mil/month, while Type 309 Cb shows about . 3 t o . 5 mils/month.
Page 16
Higher chromium con ten t o f f e r s t h e most b e n e f i t t o improve co r ros ion r e s i s t a n c e
whi le f r i n g e advantages of low s i l i c o n , low manganese and low carbon i n t h i s environ-
ment a r e l e s s known.
The t e s t o f f e r s some va lue because it r e p r e s e n t s s t r o n g n i t r i c cond i t ions a s i n
t h e a p p l i c a t i o n , and a l s o because i t is a s t anda rd we l l recognized t e s t f o r s t a i n l e s s
s t e e l s .
Th i s t e s t w a s conducted under r e f l u x cond i t ions with co ld f i n g e r condensers f o r
f i v e 48-hour per iods i n b o i l i n g a c i d . A l l samples were p rebo i l ed 3 hours and weighed
be fo re r e g u l a r t e s t s were s t a r t e d .
r a t e s were c a l c u l a t e d i n inches p e n e t r a t i o n per month. Welded specimens were examined
, for k n i f e - l i n e and i n t e r g r a n u l a r co r ros ion .
t h r e e annealed cond i t ions and a l s o a f t e r s e n s i t i z i n g 1 hour a t 1200°F.
New a c i d was used f o r each per iod . Co'rrosion
Unwelded samples were t e s t e d i n t h e
. ( e ) P i t t i n g T e s t - 6% F e r r i c Chlor ide
The informat ion provided i s o f t e n h e l p f u l s i n c e t h e presence of c h l o r i d e ion a s
a contaminant i n processes can cause hazardous r a p i d p e n e t r a t i o n of v e s s e l wa l l s by
p inho le p i t t i n g . Higher n i c k e l con ten t s a r e known t o be h e l p f u l .
This t e s t r e p r e s e n t s p i t t i n g under s t r o n g l y depo la r i z ing cond i t ions . Specimens
were t o t a l l y immersed a t room temperature and examined p e r i o d i c a l l y for evidence of
p i t t i n g . Freedom from p i t s a f t e r 300 hours i n d i c a t e s a high degree of c o r r o s i o n
r e s i s t a n c e t o l o c a l i z e d a t t a c k by halogens. No weight l o s s e s were c a l c u l a t e d f o r
p i t t i n g t e s t s . ( f ) 0.5M S u l f u r i c Acid a t 200°F
No p resen t s t a i n l e s s s t e e l s w i l l r e s i s t t h i s s o l u t i o n . I n t h e absence of n i t r i c
a c i d or f e r r i c s u l f a t e as i n h i b i t o r s , a t t a c k due t o . 5 M s u l f u r i c is severe . I t . p re -
s e n t s some i n d i c a t i o n of t h e s t a b i l i . t y of t h e pas s ive cond i t ion of t h e a l l o y s involved
i n t h e program.
The t e s t s were conducted f o r 2 hours a t t h e s p e c i f i e d concen t r a t ion and tempera-
The t e s t s were maintained a t 200'F 2 1°F i n a cons t an t temperature water ba th . t u r e .
Page 1 7
r-
..-
I
-L I-
-- u ...
0
Act iya t ion i n 150'F d i l u t e 10% H C 1 was employed p r i o r t o t e s t i n g i n s u l f u r i c a c i d .
Specimens were immersed u n t i l t h e development of hydrogen bubbles on t h e su r face ,
r i n s e d i n ho t water and immediately placed i n t h e s u l f u r i c a c i d s o l u t i o n .
Resu l t s of Corrosion T e s t s :
The t a b l e s p re sen t ing r e s u l t s of co r ros ion t e s t s on shee t m a t e r i a l a r e shown
i n t h e i r e n t i r e t y a t t h e end of t h e r e p o r t i n t a b l e s p re f ixed A, f i g u r e s p re f ixed C .
Tables d e a l i n g with welded samples a r e p re f ixed B i n t h e same manner.
For purposes of d i scuss ion , va r ious p e r t i n e n t summaries w i l l be used i n t h e
t e x t t o i l l u s t r a t e and compare r e s u l t s .
General Corrosion Res is tance of Various Compositions :
A . E f f e c t of Annealing Temperature on Sheet . I
I n t h e development of new a l l o y s some knowledge of proper a n n e a l i n g . temperature
f o r b e s t c o r r o s i o n p r o p e r t i e s i s needed. Previous experience wi th unbalanced, low
n i c k e l Type 316, f o r example, i nd ica t ed t h a t annea l ing a t 2050°F was too h igh and
c o r r o s i o n r a t e s i n b o i l i n g n i t r i c a c i d were excess ive because of d e l t a f e r r i t e . An
annea l a t 1800'F c o r r e c t e d t h i s s i t u a t i o n . S imi l a r reasoning a p p l i e s t o t h e duplex
C r - N i a l l o y s and even t h e ve ry low carbon Type 309 wi th smal l amounts of f e r r i t e .
Corrosion r a t e s i n va r ious environments f o r s h e e t samples annealed a t 2050°F, 2150°F,
and 2300°F a r e compared i n Table V .
r e s u l t s f o r o the r comparisons l a t e r .
This t a b l e a l s o provides a very good summary of
$
I n genera l , v a r i a t i o n i n annea l ing temperature from 2050°F t o 2300°F has r e l a -
t i v e l y minor e f f e c t s , while a l l o y composition has a g r e a t e r i n f luence i n envir inments
such a s HN03-=HF, t h e complex mixture and even i n f e r r i c c h l o r i d e . However, t h e r e a r e
D
some s i g n i f i c a n t r e s u l t s which should b e poin ted ou t r ega rd ing annea l ing .
(a ) There seems t o be a s l i g h t gene ra l t r end f o r dec reas ing co r ros ion r a t e s
i n t h e b o i l i n g "03-HF s o l u t i o n s as annea l ing temperature i s r a i s e d from 2050'F t o
2300°F al though i n a few cases t h e r e v e r s e may be t r u e .
.. . . ~ .... .. , ._.__.__.i ".. ~ .. ... _.. - ~. . ... .. . . . _ . . . _ I _ . . . _ _ . . _ . . . I . . . ~ ..... ^ _ ._ __ . ~ . . .,
Page 18
(b) I n a l l bu t two c a s e s , i nc reas ing annea l temperature from 2050'F t o 2150°F
Rather d r a s t i c i nc reases increased c o r r o s i o n r a t e s i n t h e b o i l i n g complex mixture .
were observed with t h e t h r e e very low carbon and n i t rogen vacuum melted h e a t s , RV294,
RV296 and RV297, and t h e s e show excess ive r a t e s of 8.8, 8 .0 and 7.9 mils/month when
annealed a t 2150'F.
and t h i s unusual phenomenon w i l l b e d iscussed l a t e r .
They show seve re i n t e r g r a n u l a r s u r f a c e a t t a c k i n t h i s environment
(c) Annealing temperature has r e l a t i v e l y l i t t l e e f f e c t on b o i l i n g 65% n i t r i c
a c i d c o r r o s i o n r a t e s except aga in on two of t h e vacuum melted h e a t s , RV294 and RV297,
a s we l l as Type 309L and Type 310, a l l of which inc rease i n r a t e wi th i n c r e a s i n g
temperature .
(d) The r a t h e r e r r a t i c na tu re of t h e s u l f u r i c , a c i d c o r r o s i o n a t t a c k does not I
permit any eva lua t ion a s t o whether h ighe r annea l ing temperature is hazardous o r
b e n e f i c i a l , bu t t h e r e a p p e a r s t o be some e f f e c t , vary ing wi th composi t ions.
( e ) Among those few h e a t s s u s c e p t i b l e t o a t t a c k i n f e r r i c c h l o r i d e i t can be
s a i d t h a t vacuum melted compositions become worse wi th a h igher annea l whereas a l l
o t h e r s improve.
( f ) S ince t h e r e may be inc reas ing o r decreas ing co r ros ion r a t e s i n va r ious
s o l u t i o n s t h e cho ice of annea l ing temperature may be b e s t governed by t h e type of
environment. The a t t a c k by each s o l u t i o n is appa ren t ly d i f f e r e n t , depending upon
s t r u c t u r e of t h e a l l o y material involved.
For purposes of t h e l a t e r i n v e s t i g a t i o n , samples annealed a t 2050°F were
employed i n t h e weld t e s t s because, of m a t e r i a l l i m i t a t i o n s . The f a c t s presented
above must l a t e r be r e c a l l e d i n d i scuss ion of weld tests.
. B . E f f e c t of Composition
To avoid confusion and s i m p l i f y p r e s e n t a t i o n of d a t a f o r e a s i e r comparison,
subsequent d i scuss ion of t h e e f f e c t s of composition w i l l r e f e r on ly t o t h e 2050°F
annea l c o n d i t i o n s i n c e it a p p l i e s t o both s h e e t and weldded p l a t e tests.
INFLUENCE OF ANNEALING TEMPERATURE ON AVERAGE CORROSION RATES
SHEET SAMPLES
Heat No.
FV71
F v l l
FV20
FV 70
FV19B
FV 56
FV57
FV17A
FV19A
GD44
RV296
RV294
Type
35 Cr-20 N i
30 Cr-25 N i
30 Cr-20 N i
30 Cr-15 N i .
310 + 1 S i
310 + .03 Si + .004C
310 f .28 S i
310 + .33 Mn
310 + .02 C
310 + Cb
309 + .008 C
309 + .004 C
Annea led a t
2050°F 2 150 2300 2050°F 2 150 2300 2050" F 2 150 2300 2050°F 2 150 2300 2050°F 2 150 2300 2050°F 2 150 2300 2050 OF 2 150 2300 2050 OF 2 150 2300 2050°F 2150 2300 2050°F 2 150 2300 2050" F --- 71 50
2300 2050°F 2 150 2300
13M HNO3 .25M HF
m i 1s /mo
35 30 25 29 26 28 32 34 29 37 34 42 52 47 46 44 49 50 44 42 34 61 75 62 38 43 45 45 44 38 .
57
47 58 70 57
r;? >L
13M "03 .50M HF rnils/mo
37 42
44 39
42
*
* * * 51 48
62 58
7 1 61
75 70
72 98
53
*
*
*
*
* *
a *
64 75 .
93 30
87 89
*
*
*
Complex Mixture mils/mo Avg.
3 . 3 3 .5
3 . 1 2.6
3 .1 3.8
3.8 4 .0
3 . 3 2 .9
2 . 8 3.1
2 . 8 3 .0
3 . 1 3 .2
2.9 3 .4
3 .5 3.8
7 . 8 8 .8
6 . 2 8 .0
*
*
*
*
*
*
*
*
*
* .
*
*
65% "03 in/mo Avg.
.0018
.00020
.0002 1
.00024
.00020
. 000 18
.00020
.00018 . 000 18 -00017 .00023 .00023 .00034 . 0001 7 .00022 .00024 .00024 .00023 .00020 .00023 .00023 .00027 .00026 .00023 . 000 19 ,00031 ,00032 .00024 .00024 .0002 7 .00024 .00028 .00032 .0002 7 .00027 .00028
.5M H2s04 i n h o A V ~ .
-33 - 32 .24 - 2 2 .30 .32 .14 -26 . .25 -42 -023 * 7 1 -20 -10 .28 -16 __ .08 -18 - 23 .30 .23 .LO . 1 7 . I 7 .23 .26 .26 - 2 7 .29 .14 -25 .24 . 2 3 .38 -28 -45
FeC 13 Hours t o P i t
100 100 300 No p i t s No p i t s No p i t s 100 . 100 100 24 24 24
No p i t s No p i t s No p i t s No p i t s
24 100 N o p i t s No p i t s No p i t s No p i t s No p i t s No p i t s No p i t s 2 No p i t s % NO p i t s ~
No p i t s a No p i t s No p i t s 168 144 24
144 144 48
- TABLE V_ ( contd) -
F ~ C 13 1 3 M "03 13M "03
Amealed .25M HF .50M HF Complex Mixture 65% "03 .5H H2SO4 Hours a t mils/mo Avg. in/mo Avg:. injmo Avg. t o P i t Type mils/mo milslmo - Heat No.
59 8 5 4 2 150 55 90
RV29 7 309 -:- .008 C 2050°F ,
FY 78 309 -E .026 C
FY79 309 t- Cb
* Not Tested
2300 2050°F
54 77
_ _ * 105
2 150 54 102 2300 51 * 2050°F 69 126 2 150 60 94 2300 62 *
6.6 7.9
5.7 5.9
5 . 3 5.4
*
*
*
.00023
.00028
.00033
.00022
.00026
.00030
.00028
.00029
.00028
.16
. 2 1
.25
.35
.34
.37 - 2 7 -26 29
168 144 24 56
168 144 N o p i t s No p i t s No p i t s
7
,
h, 0
Page 21
Table V I i s a condensed ve r s ion of r e s u l t s f o r 2050'F.annealed shee t i n t h e
t h r e e HNO3-HF s o l u t i o n s , t h e complex mixture and the b o i l i n g 65% "03 t e s t . S u l f u r i c
a c i d and f e r r i c c h l o r i d e r e s u l t s , which show l i t t l e r e l a t i o n t o t h e o the r tests w i l l
be d iscussed s e p a r a t e l y .
It is immediately apparent upon inspec t ion of t h e t a b l e t h a t t h e r e a r e d r a s t i c
d i f f e r e n c e s i n co r ros ion r a t e s among t h e f i v e d i f f e r e n t s o l u t i o n s , va ry ing a s much
as 300 f o l d between b o i l i n g n i t r i c a c i d and t h e s t r o n g e s t "03-HF mixture . A second
s i g n i f i c a n t observa t ion is t h a t t h e r e i s no r e l a t i o n s h i p among t h e t e s t s , and good
c o r r c s i o n r e s i s t a n c e i n one environment does not permit a p r e d i c t i o n that propor t ion-
a l l y good performance of a n a l l o y can be expected i n one of t h e o t h e r s .
bxcept ion e x i s t s f o r t h e t h r e e "O3-HF s o l u t i o n s which show reasonable good r e l a t i o n -
s h i p to each o the r and r a t e s i nc rease p ropor t iona te ly wi th HF con ten t . For example,
a comparison of t h r e e h e a t s w i l l be shown below t o i l l u s t r a t e t h i s b e t t e r . A l l have
p r a c t i c a l l y t h e same n i t r i c a c i d co r ros ion r a t e s bu t v a s t l y d i f f e r e n t behavior i n
o t h e r environments.
Heat No. Type B o i l i n g 65% H N O l Complex Mixture 13M " 0 2 4 .5OM HF
A s l i g h t
Fv 11 30 Cr-25 N i .00024 in/mo 3 . 1 mils/mo 44 mils/mo GD44 310 Cb .00024 in/mo 3 . 5 mils/mo 64 mils/mo Fy79 309L .OOOZZ in/mo 5 .7 mils/mo 105 mils/mo
It is necessary, t h e r e f o r e , t o eva lua te a l l t h r e e type environments a t t h e same
t ime t o have any s i g n i f i c a n c e . Ind iv idua l d i scuss ion of d i f f e r e n t compositions o r
groups of compositions w i l l fo l low.
( a ) g i g h Chromium Nickel Alloys
Taking f i r s t t h e four h igh chromium n i c k e l a l l o y s , t h e s e show d e f i n i t e l y t h e
lowest c o r r o s i o n r a t e s i n t h e JmO3-HF s o l u t i o n s of a l l t h e m a t e r i a l s t e s t e d . They do
no t , however, show any d i f f e r e n t co r ros ion r a t e s t han Type 310 o r i t s mod i f i ca t ions i n
t h e complex mixtures and, i n f a c t , may even show s l i g h t l y g r e a t e r a t t a c k .
t h e i r performance i n n i t r i c a c i d i s about t h e same a s t h e o the r m a t e r i a l s i n t h e pro-
gram though perhaps a l i t t l e lower than t h e Type 309 group. Comparing' w i th Type 310
Furthermore,
Heat NO.
Fv.7 1
F v l l
I Fv20
Fv 70
FV 19B
FV56
Fv57
E'V 1 7 A
FV 19A
GD44
RV296
RV294
RV29 7
FY78
FY 79
Page 22
TA%LE UI
EFFECT OF COXPOSITJON ON CORROSION RATES
SHEET SAMPLES ANNEALED 2050°F
13M "03 f 13M "03 + 13M "03 + .075M HF .25M HF .50M HF Complex Mix 65% FINO3
Type mils/rno miIs/mo m i Is /mo mils/mo inlmo
35 Cr-20 N i
30 Cr-25 N i
30 Cr-20 N i
30 Cr-15 N i
310 -k 1.0 S i
310 + .03 S i *
310 + .28 S i
310 + . 33 Mn
310 + .020 c
310 + C b
309 + .008 C
309 + .004 C
309 + .008 C
309 + .026 C
309 + Cb
-:: . 004% c
11.3
10
1 1 . 3
17.6
16.8
17 .5
14 .5
22.3
15
13
20
19 .2
19
25.8
22.5
35
28
32
36.4
52
44
44
6 1
39
4 5 . 5
57
57 .5
58 .5
' 76.5
69
37
44
"42
51
62
73
73
72.5
73
64
93
8 7
82
105
126
L
3 . 3
3 . 1
3 . 1
3 . 8
3 . 3 .
2 . 8
2 .8
3 . 1
2 . 9
3 . 5
7 . 8
6.2
7.6
5 .7
5 . 3
. 000 18
.00024
.00019
* .00017
.00034
.00024
.00020
,0002 7
.00019
.00024
.000%4
.00027
.00023
.00022
.00028
, - ~ . .. .. . ~~ ~ . _..~ ~ , ~ . .. . . . ... .. - . . I..___.-. .~ .. ...... , - . . . . , . . .. . . , -. . . . . , . . . . -.. __ .. .. . . .
Page 23
m a t e r i a l s i n t h e HN03-HF s o l u t i o n s , t h e r e i s i n d i c a t i o n t h a t i nc reas ing chromium
con ten t t o 30% i n Heat FV20 and t o 35% i n Heat FV71 with a 20% n i c k e l l e v e l has
provided added c o r r o s i o n r e s i s t a n c e .
30% C r and 15% N i wi th t h e Type 309 s t e e l s shows even more d r a s t i c improvement f o r
an inc rease of 8% chromium con ten t . A l l of t h e s e four s p e c i a l chromium n i c k e l a l l o y s
a r e a cons ide rab le improvement over Type 309 m a t e r i a l s i n t h e complex mixture . The
e f f e c t of n i c k e l i s l e s s pronounced than chromium, a t l e a s t a t t h e h igher chromium
l e v e l s , and a change of 10% n i c k e l does not a f f e c t r a t e s t o any g r e a t e x t e n t .
S i m i l a r l y a comparison of Heat FV70 con ta in ing
The f u l l y a u s t e n i t i c 25 Cr-20 N i Heat FVll appears promising i n t h i s group,
showing good c o r r o s i o n r e s i s t a n c e and o f f e r i n g c e r t a i n advantages of a s i n g l e phase
] s t r u c t u r e .
(b) Type 310 Group
A s a whole, t h i s group o f f e r s a marked improvement over t h e Type 309 s e r i e s in
t h e complex mixture s o l u t i o n and HN03-HF s o l u t i o n s . There is v a r i a t i o n i n t h i s group,
s i n c e s e v e r a l composition f a c t o r s were inves t iga t ed .
Heat FV19B showed i n t e r e s t i n g good performance i n t h e HN03-HF s o l u t i o n s , bu t d id
appear s l i g h t l y i n f e r i o r t o a l l o the r h e a t s i n b o i l i n g 65% n i t r i c a c i d . No outs tand-
ing c o r r o s i o n r e s i s t a n c e w a s r e a l i z e d w i t h t h e very l o w s i l i c o n (and ve ry low .004%
carbon) Heat FV56 o r with t h e low .33% manganese Heat FVl ' IA, which may a c t u a l l y
The ve ry h igh s i l i c o n con ten t
be somewhat i n f e r i o r i n HNO3-HF s o l u t i o n s . From t h e more p r a c t i c a l s t andpo in t e i t h e r
a .02% carbon Type 310 o r a .O2% carbon Type 310 Cb, Heats FV19A and GD44 r e s p e c t i v e l y ,
appear promising i n t h i s group. These l a t t e r two show s u p e r i o r i t y t o Types 309L and
309 Cb i n bo th HN03-HF and complex s o l u t i o n t e s t s .
( c ) Type 309 Group
In t h i s s e r i e s t h e most paradoxica l behavior i s exh ib i t ed . Somewhat b e t t e r
c o r r o s i o n r a t e s of t h e t h r e e ve ry low carbon vacuum melted h e a t s over 309L and 309 Cb
i n HNO3-HF s o l u t i o n s i s n u l l i f i e d by t h e i r poorer r e s i s t a n c e t o t h e complex s o l u t i o n .
Page 24,
Regardless , however, t h e group a s an e n t i r e t y i s poorer than a l l o the r m a t e r i a l s
included i n t h e program. Very low carbon and n i t r o g e n con ten t of t h e vacuum melted
Type 309 h e a t s does appear a b e n e f i t i n HN03-HF.
A s a consequence of t h e comparison above, c e r t a i n conclus ions can be reached
regard ing t h e p r e f e r r e d compositions f o r b e s t co r ros ion r e s i s t a n c e .
Using t h e r egu la r Type 309L (Heat F Y 7 8 ) and Type 309 Cb (Heat F Y 7 9 ) a s a base
f o r comparison it i s q u i t e ev ident t h a t Type 310L ( a c t u a l l y .020 C i n Heat FV19A)
and Type 310 Cb (Heat CD44) o f f e r much supe r io r r e s i s t a n c e t o both t h e HN03-HF
s o l u t i o n s a s wel l a s t h e complex mixture . R e l a t i v e l y l i t t l e s i g n i f i c a n c e of compo-
s i t i o n is noted i n t h e 65% b o i l i n g n i t r i c a c i d t e s t s . Apparent ly t h e 65% b o i l i n g
i n i t r i c t e s t i s most u s e f u l f o r eva lua t ion of sensi i5izat ion and i n t e r g r a n u l a r
s u s c e p t i b i l i t y ; more of t h i s w i l l b e d iscussed l a t e r .
I n a d d i t i o n f o r t h e u l t i m a t e i n co r ros ion r e s i s t a n c e t o t h e "03-HF s o l u t i o n s ,
i t i s apparent t h a t t h e h igher chromium and n i c k e l a l l o y s o f f e r t h e . g r e a t e s t b e n e f i t .
Among t h e s e h e a t s , FV11, a 30 Cr-25 N i a l l o y which is f u l l y a u s t e n i t i c i n s t r u c t u r e ,
shows t h e b e s t c o r r o s i o n r e s i s t a n c e . None of t he h igh C r - N i a l l o y s , however, o f f e r
any b e t t e r co r ros ion p r o p e r t i e s than t h e Type 310 a l l o y s i n t h e complex mixture o r
in boiling 65% "03. Both Type 310 and t h e high C r - N i a l l o y s a r e , however, much
b e t t e r than any of t h e Type 309 all .oys i n t h e complex mixture .
F igure 2 i s a b a r graph which compares performance of .026% carbon Type 309;
Type 309 Cb; .020% carbon Type 310; Type 310 Cb; and 30% Cr-25% N i a l l o y i n t h e
13 Molar HNO3 + .25 Molar HF and i'n t h e complex mixture . It i s evident t h a t a n
improvement i n co r ros ion r e s i s t a n c e has been obtained.
C . S u l f u r i c Acid and F e r r i c Chlor ide P i t t i n g T e s t s
The r e s u l t s of both these t e s t s have no r e l a t i o n s h i p t o t h e o the r environments
and w i l l be d iscussed s e p a r a t e l y he re .
There i s no r e l a t i o n s h i p observed between s u l f u r i c a c i d co r ros ion r a t e s and
any composition p r imar i ly because co r ros ion i n s u l f u r i c a c i d under t h e s e t e s t
.: ..._ i _ _ _ j ,... .. , . ," _. ._ . ._ . - . . . . ._ -. . . . . . . . . ~.
c-
U
mil
s/m
onth
-_ -Q
. ..
U
I
+ X
09
w
P
VI
a\
w
0)
a
0
0
0
0
0
I I
Y I
1
w
N
I I
I I
1 0
0
0
0
0 F
v-11
30
Cr
- 25
Ni
mi 1s /
mon
th
I I
0
P
Iu
W
CI
cn
m
v
I I
I I
I 1
Fv-
11
FV - 1
9A
GD-4
4
FY- 7
8
N- 79
- ..
. . .
.. .
~ . ... . . .
... . . . -
__ .. -.~
__
_ .
.......
.
Page 251
cond i t ions is t ak ing p l ace i n t h e a c t i v e s t a t e , and r a t e s a r e known t o b e e r r a t i c i n
such cases . It was hoped t h a t some higher a l l o y ~ 0 1 n p ~ s i f i 0 n 6 might show p n o s i v i b y
i n t h i s t e s t . Some i n t e r e s t i n g information was learned from t h e s e t e s t s on welded
p l a t e samples. These a r e summarized i n t h e fo l lowing s h o r t t a b l e , cover ing v i s u a l
examination of t h e machined edges f o r unusual a t t a c k . End g r a i n a t t a c k , a form of
very deep l i n e s of co r ros ion a t t a c k usua l ly a s s o c i a t e d wi th t h e presence of non-
m e t a l l i c i nc lus ions
Heat No.
FV 70
I Fv71
Fv 20
F v l l
FV17A
FV 19A
Fv 19B
FV 56
FY78
R V 2 9 6
R V 2 9 4
R V 2 9 7
M79
Heats FV70 and
was observed on some m a t e r i a l s :
Descr ip t ion of S u l f u r i c Acid Test (Welded) Specimens
Heavy end g r a i n a t t a c k . Heavier band of e t ch ing . s t a r t i n g a t weld and extending out about 3/16" i n t o base meta l .
Same a s FV70
L igh t e t ch
Light e t c h
Appreciable end g r a i n a t t a c k
Light e t c h only
Light e t c h only
Trace end g ra in a t t a c k
Severe end g r a i n a t t a c k
Severe end g ra in a t t a c k
Severe end g ra in a t t a c k
Severe end g r a i n a t t a c k
Severe end g r a i n a t t a c k
FV71 con ta in t h e h ighes t amounts of d e l t a f e r r i t e . Apparent ly
the h e a t a f f e c t e d zone s u s c e p t i b l e t o s l i g h t l y more r a p i d s u l f u r i c a t t a c k i n t h e s e
a r e a s is not a c a s e of p r e c i p i t a t e d ca rb ides , but more l i k e l y d e l t a f e r r i t e .
The f e r r i c c h l o r i d e t e s t r e s u l t s a r e a l s o of i n t e r e s t , s i n c e r e s i s t a n c e t o
c h l o r i d e p i t t i n g is va luab le i n chemical process ing equipment. F a i l u r e due t o r a p i d
Page 20
pene t r a t ion of a tank wal l can he hazardous.
p i t t e d m a t e r i a l i s i l l u s t r a t e d by F igure 3 f o r one of t h e welded p l a t e specimens.
The t y p i c a l appearance of a deeply
C e r t a i n m a t e r i a l s showed very good r e s i s t a n c e t o p i t t i n g i n 300 hours exposure.
It i s s i g n i f i c a n t t o no te t h a t t h i s environmer,t was found t o be r a t h e r s e n s i t i v e
t o d e l t a f e r r i t e . Those h e a t s which f a i l e d by p i t t i n g were i n every i n s t a n c e
compositions con ta in ing d e l t a f e r r i t e even i n s m a l l amounts of 2% o r 3%. There i s
no r e l a t i o n s h i p between f e r r i t e con ten t and t ime t o p i t t i n g , however.
E f f e c t of Welding or S e n s i t i z i n g on Corrosion Res is tance :
A . Welding
The r e s u l t s of co r ros ion t e s t s on a s welded samples appear i n Tables B - 1 t o
I B - 5 i n c l u s i v e a t t h e end of t h e r e p o r t . While t h e co r ros ion r a t e s a r e of g r e a t
i n t e r e s t , they a r e inf luenced by c e r t a i n f a c t o r s more c r i t i c a l which demand v i s u a l
o r microscopic in spec t ion , namely end g r a i n a t t a c k , weld a t t a c k o r p i t t i n g and
poss ib ly i n t e r g r a n u l a r a t t a c k .
F igure 4 i s a photograph of s e l e c t e d samples a f t e r tes ts i n t h e b o i l i n g c-omplex
s o l u t i o n of n i t r i c a c i d and s u l f u r i c a c i d p lus c e r t a i n s a l t s . These were c u t f o r
microscopic examination be fo re phot.ographing. I n genera l , t h e ex ten t of a t t a c k i s
much l e s s than i n t h e n i t r i c - h y d r o f l u o r i c s o l u t i o n s shown l a t e r . NO s eve re weld
a t t a c k o r p i t t i n g has occurred. However, c e r t a i n hea t s show f a i n t evidence of
a t t a c k i n h e a t a f f e c t e d zones i n t h i s s o l u t i o n . Although it is somewhat d i f f i c u l t
t o no te from t h e photograph, a l l t h e samples show s l i g h t l y d i f f e r e n t a t t a c k i n t h e
h e a t a f f e c t e d zone than t h e base meta l .
bands of a t t a c k extending out from t h e weld t o about 3/16" o r 1/4".
N 7 9 , FV17A, and FV17B show apparent narrower bands of a t t a c k very c l o s e t o t h e
weld. F V l l shows a broad band of a t t a c k which s ta r t s beyond 1/8" from t h e weld.
A l l o t h e r h e a t s show no a c c e l e r a t e d l o c a l i z e d a t t a c k i n t h i s c o r r o s i v e medium.
Heats RV294, RV296 and RV297 show apparent
Heats FY78,
I n F igure 5 we have shown a l l the weld specimens a f t e r they have been t e s t e d
i n t h e b o i l i n g 13 molar n i t r i c -:- 0.25 molar hydro f luo r i c s o l u t i o n . I n t e r g r a n u l a r
6'y0 F'I:RRIC C I I L O K I D E P I T T I N G TEST
HEAT FV-20
PITTED 20 I-IRS BASE NETAL PITTED 96 IlRS IN VELD
F i l m 6994
FIGURE 3
i-:. , . . I I. .. , CY".. P' . .
. '<.
i ; I \ .~
.. -. .......
FV-17B 3 . 5 m i l s / m o
F V - 1 7 A 3 . 5 m i l s / m o
..... .'.' ...
F Y - 7 8 4.9 rnils/mo
Film G995
, RV-E94 4 . 9 m i l s / m o
RV-297 5 . 2 m i l s / m o
FY-79 4.6 rn l l s /mo
FIGURE 4
r---
. - _. _I - . -
HIGH C R - N I TYPE 310 GROUP TYPE 309 GROUP
FV-71 4 2 m i l s / m o
FV-19B 56 mils/mo
RV-296 82 m i l s / m o
FV-11 45 mils/rno
FV-56 59 m i l s / m o
RV-294 68 ;r i ls/mo
. . . . . . .-..:. .... .... 6,- : ' g ./" .?" .,
' , :I' -. - , -~
I <.- t
6". ...... -. .. ......... ........ I
FV-20 35 m i l s / m o
Fv-57 50 m i l s / m o
RV-297 60 m i l s / m o
-.
- . . . . .~ . . . . . - '7
. . %..ai !
i
FV-17A 7 1 rni ls /mo
FY-78 7 2 mils/mo N - 7 0
54 m i l s / m o
N-19.4 39 m i l s j m o
- - - AS WELDED SAMPLES ' c , 2
- - AFTER S I X - 2 4 HOUR PERIOIJS
I N B O I L I N G 131? HNO3 + .25M HF GD-44
49 m i l s / m o
la .............. .. . . . . . . . . ..-.L.-. -....---,..-.- ..................................... -..-.. .-.. l__.l__ __- ,. .
Film G996
FIGURE 5
............... . ............. .- ----------I--..--.~-.-____I__. _-_______. .. . . . . ..-......; .L :.:z-::.L--zzz,--- ................ ...... ........... ........ . .
Page 2 7
a t t a c k is very evident on Heat FV11, and some apparent s l i g h t a c c e l e r a t e d a t t a c k
ad jacen t t o t h e weld can be f a i n t l y seen on Heats FV193, Fv56, FV71, W19A and
FY78.
t h e Type 309 Cb wi th f i l l e r meta l of t h e same composition.
p i t t i n g of t h e weld and base meta l ad jacen t t o t h e weld on Heat N 1 7 A , a " 3 3 %
manganese Type 310.
It i s a l s o obvious t h a t s eve re weld d e t e r i o r a t i o n has occurred OE Heat FY79,
There was apprec i ab le
The appearance of samples i n the, b o i l i n g 13 molar "03 + .50 molar HF so.Lution
i s s i m i l a r t o t h i s photograph with t h e except ion of more seve re a t t a c k of F V l l and
FY79. Samples FV19B, FV56, FV19A and FY78 l ikewise appear t h e same i n a l 1 , t h r e e
"03-HF s o l u t i o n s , with a f a i n t l i n e of a t t a c k ad jacen t t o t h e weld but which is not
l i n t e rg ranu la r .
l a t t e r samples i n any of t h e t h r e e s o l u t i o n s .
The depth of a t t a c k i s not more than .001" on any of t h e s e four
To b e t t e r r e p o r t t h e r e s u l t s of a t t a c k i n t h e weld and t h e heat. a f f e c t e d zones,
t h e fo l lowing Figure 6 and Table V I 1 have been employed t o he lp d e s c r i b e t h e a r e a s
i n ques t ion . A v i s u a l r a t i n g of t h e i n t e n s i t y of a t t a c k i n both environments i s
given i n
1 -
2 -
3 -
4 -
P -
x - E -
The
s o l u t i o n
Table V I I . Numerical r a t i n g s used a r e descr ibed a s fo l lows:
Neg l ig ib l e a t t a c k wi th r e s p e c t t o ad jacent a r e a s
Slight acce lera ted a t t a c k less t han .004" w i t h r e spec t t o ad jacen t a r e a s
Acce lera ted a t t a c k up t o .020" with r e s p e c t t o ad jacen t a r e a s
Very severe a t t a c k
P i t t i n g
D e f i n i t e i n t e r g r a n u l a r
End g r a i n a t t a c k
average co r ros ion r a t e s f o r a l l t h r e e HN03-HF s o l u t i o n s and t h e complex
a l s o appear i n Table VII.
.... .... .-. . ... .. .. - .. .... ... .. . . . - -. - ..... .. . _.___ .. - . .
c-
a
rl Q
Ja
3
4
a 4
z aJ 3
a
rl a, 3
VI
w
0 k
8 k
l4-I U
0
U
E k
w
a
rl
P 4
rl
a, 3
a
U
rl a, 3
w 0
- N m
E k w
m
u aJ E
4
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U
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rb n
a, C 0 N
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rl
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.a,
U
U
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w
rp
a c a,
0" a aJ a a, c
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a, C
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TABLE V L L
VISUAL RATING OF WELDED SAMPLES APTER CORROSION TESTS I N 13 MOLAR "03 + .SO MOIAR HF
AND LN COMPLEX MIXTURE
Corrosion Rates i n Complex Mixture Surface Welded HNO3 - .50 Molar HF 1 3 ~ "03 + Rate Grain Boundary
Re.?+ No. Type With B, C p E E .07% .25M .50M & C E E mils/mo Etch
W71 35 Cr-20 Ni 310 1 1 1 2 3 2 3 2 26 42 85 1 1 1 1 E l 1 1 1 3.8 No
F v l l 30 Cr-25 Ni 310 1 1 P 1 2 3 x 1 4 x 2 17 45 7 1 1 1 1 1 2 1 2 x 1 3.7 Yes
w 2 0 30 Cr-20 Ni 310 1 1 1 2 2 1 1 1 14 35 76 1 1 1 1 1 1 1 1 3.4 No
Fv 70 30 Cr-15 Ni 310 1 1 1 E . E 1 2 1 25 54 83 1 1 1 1 1 1 1 1 4.6 No
FV19B 310 + 1 Si 310 1 1 3 P 3 E 3 E l 2 1 23 59 94 1 1 1 1 1 1 1 1 3-8 Yes
N 56 310 + .03 Si 310 1 3P 3P 1E 1E 1 2 1 30 59 9 1 1 1 1 1 1 1 1 1 2.8 Yes
Pv57 310 + .28 Si 310 1 2 P 2 P 1 1 1 1 1 27 50 92 1 1 1 1 2x 1 1 1 --2.9 Yes
FV17A 310 + .33 Mn 310 4P 4P 4P 1E 1E 4P 1 1 30 11 115 1 1 1 1 1 1 1 1 3.5 Yes
PI 19A 310 + .020 C 310 3P 3P 4P 2E 2E 1 2 1 22 39 8 7 1 1 1 1 1 1 1 1 3.2 Yes
W17B 310 + .018 C 310 1 1 3 P 1 1 1 1 1 23 59 122 1 1 1 1 1 2 1 1 3.5 Yes
GD44 310 Cb GD44 1 1 2 F 1 1 1 1 1 27 46 92 1 1 1 1 1 1 1 1 3.7 Yes
1 1 1 1 1 2 2 1 5.1 Y e s RV 29 6 309 + .008 C RV296 2 2 2 1 1 1 1 1 36 82 133
1 1 1 1 3 x 2 2 1 4.9 Yes 38 68 149 RV294 309 + .004 C RV294 3 3 3 1 1 1 1 1
RV29 7 309 + .008 C RV297 2 2 ' 2 1 1 1 1 1 34' 70 122 1 1 1 1 3 x 2 2 1 5.2 Trace
pY78 309 + .026 C F178 1 1 1 2 E 2 E l 1 2 38 72. 122 1 1 1 1 1 2 x 1 1 4 . 9 Yes
my79 309 + Cb FY79 4 4 4 1 ' 1 1 1 1 70 118 193 1 1 1 1 3X 3X 1 1 4.6 Yes
Page 28
No d e f i n i t e a c c e l e r a t e d a t t a c k could be observed on any of t h e b o i l i n g 65%
&-u - n i t r i c a c i d weld t e s t specimens, even under 30X magni f ica t ion . The occas iona l
s l i g h t l y higher r a t e s on welded p l a t e was a t t r i b u t e d t o somewhat rougher s u r f a c e s
and s l i g h t t r a c e s of end g r a i n a t t a c k ( o f t e n ccmmon t o l abora to ry s i z e h e a t s ) .
There was no a c c e l e r a t i o n of co r ros ion r a t e s from pe r iod t o per iod , a phenomenon
observed when i n t e r g r a n u l a r a t t a c k occurs . -- However, t o more c a r e f u l l y examine any compositions suspec ted of i n t e r g r a n u l a r
a t t a c k , s h e e t samples of each composition and s p e c i a l s e l e c t e d p l a t e s were reannealed
a t 2050°F and then s e n s i t i z e d f o r one hour a t 1200°F and t e s t e d i n b o i l i n g . 6 5 % n i t r i c
a c i d . Resu l t s of s e n s i t i z e d s h e e t appear i n Table A - 7 and s e n s i t i z e d p l a t e i n Table
9-6 a t end of t h e r e p o r t . I n both cases some inc rease of co r ros ion r a t e was observed,
B .-.- -u -
- n
but s u r p r i s i n g l y t h e s e samples showed no i n t e r g r a n u l a r s u r f a c e a t t a c k nor adid r;hey -u -_ show inc reas ing co r ros ion r a t e s from per iod t o pe r iod , which would tend t o f u r t h e r
- P confirm t h a t no i n t e r g r a n u l a r a t t a c k had occurred.
I f we r e f e r t o t h e f i v e hea t s we compared previous ly i n the ba r graphs i n
F igure 2 a s t h e most promising compositions, and s e l e c t them f o r f u r t h e r s tudy a s
i n Table V I I I , we w i l l no t e a l l have increased r a t e s a s s e n s i t i z e d .
TABLE VI11 -- - EFFECT OF SENSITIZATION
N I T R I C A C I D CORROSION RATES IPM
la n W Heat N o . Type Annealed 2050°F S e n s i t i z e d 1200°F Ra t io
FVll 30 Cr-25 N i .00024
GD44 Type 310 Cb 4 .02 C .00024
FY79 Type 309 Cb .00028
FV 19A Type 310 + .020 C .00019
FY78 Type 309 -+ .026 C .00022
.00034 1.4
.00041 2.2
.00029 1 . 2
.00046 2 . 1
.00039 1.4
I f t h e increased r a t e s (even without i n t e r g r a n u l a r a t t a c k ) have any s i g n i f i c a n c e ,
then t h e r e aga in appears t o be a high degree of promise f o r Heat GD44, t h e Type 310
with .02% carbon and .22% columbium.
Based on t h e co r ros ion t e s t r e s u l t s and
V I I , A - 7 , B-6 and V I I I , c e r t a i n observa t ions
( a ) The n i t r i c -HF s o l u t i o n is far more
v i s u a l l o c a l i z e d a t t a c k .
(b) End g r a i n a t t a c k i s a problem wi th
a r e a r a t i o i s apprec i ab le . Laboratory h e a t s
Page 29
v i s u a l s t u d i e s r epor t ed i n Tables
can now be made:
severe i n i t s e f f e c t t o produce
heavy s e c t i o n s where edge t o s u r f a c e
a r e more prone t o show t h i s t han
commercial product ion m a t e r i a l . In a c t u a l equipment, t h i s would not be t h e s e r i o u s
f a c t o r i t i s he re .
( c ) P i t t i n g of t h e weld s u r f a c e and e s p e c i a l l y ends can have a s e r i o u s
in f luence on
I (d ) No
weld a t t a c k .
( e > I n
co r ros ion r a t e i n HN03-HF t e s t s .
v i s u a l end g r a i n a t t a c k is observed i n ' t he complex mixture , nor s eve re
s p i t e o f mild p i t t i n g on the ends of t h e weld ( a r e a C ) on GD44, r e s u l t s
i n d i c a t e t h a t .020% carbon Type 310 Cb p resen t s t h e b e s t co r ros ion r e s i s t i n g as-welded
s u r f a c e f o r t h e "03-HF s o l u t i o n s . Heat FV20, a 30 Cr-20 N i a l l o y is a l s o good.
Nei ther show l o c a l i z e d s u r f a c e attac:k. FV19A, a .020 carbon Type 310 a l s o showed
a gray e t ch i n t h e h e a t a f f e c t e d zone, bu t co r ros ion r a t e s were high due t o a c.om-
b i n a t i o n of weld p i t t i n g and end g r a i n a t t a c k .
( f ) Regardless of l o c a l i z e d a t t a c k e f f e c t s , t h e Type 310 compositions and. t h e
high C r - N i a l l o y s a r e supe r io r t o Type 309 i n both media.
(g ) Heats RV294, RV297, FY78 and M79, t h e Type 309 s e r i e s , a l l show a t t a c k
immediately ad jacen t t o t h e weld (aZea F on drawing Figure 6 ) i n t h e C L .:lex so lu -
t i o n , but none i n t h i s a r ea when sub jec t ed t o "03°F tes ts .
Metal lographic Examinat ion:
Samples of welded p l a t e were a l l sub jec t ed f i r s t t o examination a t 30X magnifica-
t i o n t o examine t h e su r face , welds and hea t a f f e c t e d zones more c r i t i c a l l y and then
each was c u t , me ta l log raph ica l ly pol i shed , e tched with oxa l i c e tchant and examined a t
250X. The examination a t 30X was q u i t e s u r p r i s i n g .
,\ . .- . . ... . . . . . . . . . . .. . . _ . I . .~ . .
Page 30
A . 30X Study
A s e a r l i e r r epor t ed , no i n t e r g r a n u l a r a t t a c k could be seen on t h e b o i l i n g 65%
n i t r i c a c i d samples. It appears t h a t t h e n i t r i c a c i d t e s t s i s not a s s e n s i t i v e a s
t h e o the r two s o l u t i o n s f o r d e t e c t i n g i n t e r g r a n u l a r s u s c e p t i b i l i t y . An examination
of weld samples a f t e r t e s t i n g i n HN03-HF s o l u t i o n s and the complex mixture revea led
t h e observa t ions r epor t ed i n Table I X .
.25M HF showed t h e same r e s u l t s a s i n t h e t a b l e bu t t o somewhat l e s s e r degree .
Tes t s i n 13M HN03-.075M HF and 13M "03-
TABLE I X
30X STUDIES FOR SURFACE ATTACK BY HNO3-HF AND COMPLEX SOLUTIONS
Heat No.
I FV71
F v l l
FV20
FV 70
FV 19B
FV 56
Fv57
FV17A
FV 19A
GD44
RV296
RV296
RV297
Type
35 Cr-20 N i
30 Cr-25 N i
30 Cr-20 N i
30 Cr-15 N i
310 + 1 S i
310 + . 03 S i
310 + . 2 8 S i
310 + . 33 Mn
310 + .02 C
310 + Cb
309 + .008 C
309 f .004 C
309 + .008 C
13M "03 -t .5OM HF
Line 1/8" from weld. No I G
I G ad jacent t o weld
No I G
No I G
Etch 1/4" from weld
No I G
N o I G
P i t s ad j acen t t o weld
Etch 1/4" from weld
No I G
Undercut weld. No I G
Undercut weld. No I G
Undercut we1.d. No I G
Complex __
'End g r a i n a t t a c k . No I G
Deep g r a i n boundary e t ch -a l so i n weld
No I G
No I G
Deep g r a i n boundary e t ch -a l so i n weld
No I G
Deep gra in boundary etch-also i n weld
Deep g r a i n boundary e t c h - a l s o i n weld
Deep g r a i n boundary e t ch -a l so in we Id
Deep , g r a i n boundary e t ch -a l so i n weld
Very rough I G s u r f a c e
Very rough I G s u r f a c e . I G a t edge of weld
Very rough I G su r f ace . I G alt edge of weld
TABLE I X (contd) --
Heat No. Type 13M HNO3 + .50M HF
FY78 309L Etch 1/4" from weld
FY 79 309 C Severe a t t a c k of weld
The cond i t ion observed on t h e complex s o l u t i o n
Page 31
C-gmp 1 ex
Deep g r a i n boundary e t ch . Also I G
Rough I G su r f ace . Deep I G a t edge of weld
samples was s t a r t l i n g s i n c e it
occurs i n base meta l completely unheated by welding. The unusual deep g ra in boundary
e t ch o r perhaps i n t e r g r a n u l a r s u r f a c e a t t a c k i s p i c t u r e d i n F igure 7 taken a t 3 0 X on
sample FV19A. Note t h a t t h e a t t a c k occurs a l s o a long g r a i n boundaries i n t h e weld.
This c o n d i t i o n i s not t h e commonly observed i n t e r g r a n u l a r s u r f a c e a t t a c k sometimes
encountered a f t e r annea l ing and p i ck l ing . It was a l s o q u i t e ev ident on machined and
pol i shed edges; such edges were prepared a s a f i n a l s t e p be fo re c o r r o s i o n t e s t i n g and,
t h e r e f o r e , never had any annea l s c a l e on them. Based on subsequent 250X microscopic
examination, t h i s i n t e r g r a n u l a r e t ch ogcurs i n t h e absence of v i s i b l e g r a i n boundary
p r e c i p i t a t e . A t t h e p re sen t t ime t h i s phenomenon i s not understood but p o i n t s t o a
p o s s i b l e i n v i s i b l e p r e c i p i t a t e of some type t h a t is s e n s i t i v e t o a t t a c k i n t h i s
s p e c i f i c complex s o l u t i o n environment. In c o n t r a s t t h e more s e v e r e l y c o r r o s i v e
HN03-HF s o l u t i o n s d i d not produce i t i n any ins tance .
I
Another i n t e r e s t i n g f a c e t of t h i s unusual g r a i n boundary e t ch e f f e c t i s t h a t i t
does no t occur with t h e duplex s t r u c t u r e s i n Heats FV70, FV71 and FV20. The s u r f a c e
a t t a c k can occur f a r from any weld; it does not p e n e t r a t e a f u l l g ra in deep, and a s a
ma t t e r of f a c t could not be seen i n a 250X microscopic examination of t h e c r o s s sec -
t i o n . Because of our concern
samples which had been t e s t e d
t o view samples wi th a 2050'F
about t h i s s e r i o u s cond i t ion , we
i n t h e complex s o l u t i o n ; h e r e we
anneal and a 2150'F annea l . The
i n Table X.
examined a l l sheet:
had an oppor tun i ty
r e s u l t s a r e t a b u l a t e d
j _ . .-. - , . , - . ,.... .:..> :. . . -1. - . .. . . .. _. . . . .. . . .. . - . .
Y
F i l m G993
FIGURE 7
Sample FV19A
30X
Showing Deep Grain Boundary Etch i n Base Metal and Weld' After Tests i n Complex Mixture
,- . - ..... .. _ _ . ~ .,... ..,. .
Page 32
TABLE 5
30X EXAMINATION OF SHEET SAMPLES AFTER COMPLEX SOLUTION TEST
Heat No. Type - 2050°F 2150°F
FV71 F v l l FV20 FV 70 FV 1 9 B FV56 FV17A FV 19A GD44 RV296 RV294 RV29 7
I FY78 FY 79
35 Cr-20 N i 30 Cr-25 N i 30 Cr-20 N i 30 Cr-15 N i 310 + 1.0 S i 310 + .03 S i 310 i . 33 Mn
310 Cb 310 + .02 C
309 + .008 C 309 + .004 C 309 + .008 C 309L 309 Cb
No NO
N o No Trace Yes Yes-mild Yes Yes-s evere Ye s - s ever e Yes - s ever e Yes -sever e Yes -sever e Trace
No Yes No NO
Heavy No Yes - m i Id Yes -sever e Yes Yes -sever e Yes -sever e Yes -sever e Yes - s ev e r e Yes -heavy
It may be concluded t h a t t h e r e probably is a s u s c e p t i b l e p r e c i p i t a t e of some
type t h a t i s i n most ca ses formed a t h igher temperatures . We have been unable t o
s e e any p r e c i p i t a t e microscopica l ly . It could expla in t h e ex i s t ence of heavier o r
g ra in boundary a t t a c k on Type 309 m a t e r i a l s commencing immediately a t t h e edge of
t h e weld and extending a s h o r t d i s t a n c e i n t o t h e base meta l , f o r t h i s a r ea has reached
very high temperatures (above 2050°F) next t o the fus ion zone. While t h e a t t a c k may
be too s u p e r f i c i a l t o be d e t e c t e d i n co r ros ion r a t e s , neve r the l e s s i t should be of
concern and deserves much f u r t h e r i n v e s t i g a t i o n beyond t h e scope of t h i s a l l o y develop-
ment program.
B . Metal lographic S tud ie s
A l l t h e samples were examined me ta l log raph ica l ly t o e s t a b l i s h s t r u c t u r e s and
presence of g r a i n boundary p r e c i p i t a t e s . I n a d d i t i o n they were examined f o r evidence
of s u r f a c e a t t a c k . The r e s u l t s a r e summarized i n Tables X I and X I 1 and i l l u s t r a t e d
with a s e r i e s of photomicrographs t h a t fol low.
... .
Page 33
:n TABLE XI -- - METALLOGRAPHIC EXAMINATION OF WELD HEAT AFFECTED ZONE
AFTER TESTS I N COMPLEX MIXTURE
Wre Id A t t a c k
None
None
None
None
"one
None
None
None
None
None
None
None
None
None
None
None
De l t a F e r r i t e
Yes
None
Yes
Yes
None
None
None
None
None
None
None
Trace
Trace
Trace
Trace
None
Weld - 'u Heat Eo. Type Grain Boundary Carbides i n Heat Af fec t ed Zone S u r f a c e At t ack
None -
B FJ71
P Fv20
5 FV70
-_ EV 19B
-
FV56
0 Fv57
L FV 19A
FV 1 7 B
GD44
RV29 6
RV294 ' RV297
R FY78
P FY79
l-3
35 Cr-20 N i
30 Cr-25 N i
30 Cr-20 N i
30 Cr-15 N i
310 -L 1 S i
310 + .03 Si
310 + .28 S i
310 + .33 Mn
310 1- .020 C
310 + .018 C
310 + Cb
309 + .008 C
309 + .004 C
309 + .008 C
309 + .026 c
309 + Cb
310
3 10
3 10
3 10
3 10
3 10
3 10
3 10
3 10
3 10
GD44
RV296
RV294
RV297
N78
FY79
Very s 1 i g h t p r ec i p i t a - t ion
Continuous Some I G a t t a c k
None
None
Trace
None
'None
Some discont inuous p r e c i p i t a t i o n
None None
None Very l i g h t p r e c i p i t a - t i on
None None
Very l i g h t p r e c i p i t a - tr ion
None
None
None
None
None
Nos e
None
None
I, igh t p r ec i p it a t i on
Very l i g h t
None
Very l i g h t p r ec i p i t a - t ion
Very l i g h t p r e c i p i t a - t ion
L igh t p r e c i p i t a t i o n
None
There was no microscopic evidence of i n t e r g r a n u l a r a t t a c k ad jacen t t o t h e weld
on any of t h e Type 310 m a t e r i a l s . Among t h e h igh C r - N i a l l o y s only t h e 35 C r - 2 Q N i
composition showed any evidence of a t t a c k a d j a c e n t t o t h e weld. These r e s u l t s a r e
: . , . . .... ... . ... . . . . . . . . _ I _ . . . . . . . . .
Page 34
encouraging s i n c e t h e Type 310 Cb and the ,020 C Type 310 which a r e promising have
showrl ne inLergranular o u s c o p f i b i l i t y i n t h i e envirenmenf, and in a d d i f i e n Ghca w@hd
depos i t of .018% carbon Type 310 (from Heat FV17B) shows no s u s c e p t i b i l i t y . Even t h e
h e a t s , RV294, RV297, and N 7 9 , which showed i n d i c a t i o n of a heav ie r l i n e of a t . tack
a t t h e hea t a f f e c t e d zone v i s i b l e on t h e edges of welded p l a t e specimens, do n o t show
s e r i o u s i n t e r g r a n u l a r p e n e t r a t i o n o r g r a i n i n e s s when examined me ta l log raph ica l ly a t
250X.
F igures 8 t o 14 i n c l u s i v e were s t r u c t u r e s a t t h e s u r f a c e of va r ious samples a f t e r
t e s t i n g i n t h e complex s o l u t i o n s . These have been s e l e c t e d t o i l l u s t r a t e va r ious
r e p r e s e n t a t i v e s t r u c t u r e s and what they show a f t e r co r ros ion t e s t s i n t h i s environ-
I ment.
F igure 8 i s a photograph of Heat FV11, t h e a u s t e n i t i c 30% Cr-25 % N i s t e e l i n
t h e weld hea t a f f e c t e d zone.
and d e f i n i t e i n t e r g r a n u l a r a t t a c k a t t h e s u r f a c e .
Note the presence of a cont inuous c a r b i d e p r e c i p i t a t e
F igure 9 i s a duplex a u s t e n i t i c - f e r r i t i c s t r u c t u r e of Heat FV71, a 30 Cr-15 N i
a l l o y i n t h e weld hea t a f f e c t e d zone. There was no v i s u a l evidence of a c c e l e r a t e d
a t t a c k a t weld h e a t a f f e c t e d zones and t h i s i s confirmed by a microscopic examination.
F igures 10 and 11 rep resen t Type 310 h e a t s without a g ra in boundary p r e c i p i t a t e
i n the weld h e a t a f f e c t e d zone. Note t h e ve ry rough s u r f a c e i n F igure 10; t h i s was
p re sen t a l l over the s u r f a c e of t h e base meta l even i n a r e a s remote from weld h e a t
a f f e c t e d zones. This could be t h e s u r f a c e e t ch descr ibed above and shown i n Fi.gure
7 , bu t no te t h a t t h i s is a m a t e r i a l which has no v i s i b l e g r a i n boundary p r e c i p i t a t e .
In Figure 11 some discont inuous p r e c i p i t a t e i s v i s i b l e i n t h e hea t a f f e c t e d zone, and
t h e r e i s some s l i g h t evidence of a t t a c k of a p i t t i n g n a t u r e bu t no t n e c e s s a r i l y a t
t h e g r a i n boundaries .
F igure 12 i s t h e vacuum melted Heat RV296 with ve ry low
d e l t a f e r r i t e . The a rea shown i s immediately bes ide t h e edg
carbon
of t h
which shows
weld. There i s
Page 35
no g r a i n boundary ca rb ide p r e c i p i t a t e , ye t some t r a c e s of s u r f a c e e t ch a r e apparent .
The s u r f a c e appears t he same i n base meta l a r e a s remote from t h e weld hea t a f f e c t e d
z:6tie.
Figure 13 r e p r e s e n t s .02% carbon Type 310 Cb i n t h e weld hea t a f f e c t e d zone.
The t r a c e amounts of d i scont inuous g r a i n boundary p r e c i p i t a t e have not promoced any
i n t e r g r a n u l a r co r ros ion . The s u r f a c e showed t h e unusual g r a i n
examined a t 30X bu t t h e cond i t ion e x i s t e d a l l over t h e s u r f a c e
weld hea t a f f e c t e d zones.
boundary e t c h when
and not confined t o
F igure 14, t h e Type 309 Cb weld, showed no evidence of a t t a c k i n t h e complex
b o i l i n g mixture . This i s i n s u r p r i s i n g c o n t r a s t t o t h e performance of t he same weld
i n b o i l i n g "03-HF s o l u t i o n p i c t u r e d i n Figure 19 l a t e r . I
Table X I 1 dea l s wi th microscopic examination a t 2 5 0 X of samples t h a t showed any
susp ic ion of p o s s i b l e i n t e r g r a n u l a r co r ros ion i n t h e b o i l i n g HN03-HF s o l u t i o n s . Again
i t was seen t h a t no i n t e r g r a n u l a r co r ros ion had occurred i n t h i s s o l u t i o n o t h e r than
t h e one in s t ance of FV11, t he a u s t e n i t i c 30 Cr-25 N i a l l o y which a l s o was a t t a c k e d i n
t h e complex s o l u t i o n .
The a t t a c k i n HN03-HF s o l u t i o n s on t h e a l l a u s t e n i t i c samples i s seve re and
appears a s i n F igure 15. No a t t a c k i s evident a t g r a i n boundaries i n s p i t e of t h e
d iscont inuous p r e c i p i t a t e .
F igure 16 d e a l i n g wi th Heat FV-11 shows i n t e r g r a n u l a r a t t a c k a s ' expec ted . F igure
1 7 i s t h e duplex s t r u c t u r e 35 Cr-20 N i hea t a t t he h e a t a f f e c t e d zone. The same
s t r u c t u r e and s u r f a c e a t t a c k i s a l so seen a t a r e a s remote from t h e hea t a f f e c t e d zone.
The
Although
t h e r e i s
f i n a l two f i g u r e s , 18 and 19, show t h e Type 309 Cb base meta l and weld,.
F igure 18 shows no s u r f a c e a t t a c k i n t h e hea t a f f e c t e d zone bes ide the weld,
s e r i o u s d e t e r i o r a t i o n of t h e weld i t s e l f (F igu re 19 ) . There i s no evidence
from meta l lographic examination t o expla in t h e r a p i d co r ros ion of t h e Type 309 Cb i n
"03-HF s o l u t i o n .
of d e t e r i o r a t i o n .
The Type 310 Cb weld i n t h i s program i s not s u b j e c t t o t h i s type
-. . . . ~ . . . . . . . . . . . .
FIGURE 8
P l a t e 200E8
250X Oxal ic
,Heat FVl l
Weld Heat A f f e c t e d Zone A f t e r
T e s t i n Complex- S o l u t i o n
F I G U R E 9
P l a t e 200E9
250X Oxal ic
Heat F’V71
Weld Heat A f f e c t e d ’Zone A f t e r
T e s t i n Complex S o l u t i o n
,
...... ........ ..... .... ........ _- ..-.. ~. .~... . - ..I_---. .. -. ........... - .- . . . . . . . . . . . . . . .
FIGURE 10
P l a t e 200E10
250X Oxal ic
Heat FV17A
Weld Heat Af fec t ed :Zone A f t e r
T e s t i n Complex .Solu t ion
FIGURE 11
P l a t e 2 0 0 E 7
250X Oxal ic
Heat FV19B
Weld Heat Af fec t ed Zone A f t e r
T e s t i n Complex S o l u t i o n
I
FIGURE 12
P l a t e 201E3
250X Oxalic
Heat RV296
Weld Heat A f f e c t e d Zone A f t e r
T e s t i n Complex S o l u t i o n
FIGURE 13
P l a t e 201E1
250X Oxalic
Heat GD44
Weld Heat A f f e c t e d Zone A f t e r
T e s t i n Complex S o l u t i o n
FIGURE 14
P l a t e 201E2
250X Oxalic
Heat FV79
Weld i n Heat FV79 Type 309Cb
A f t e r T e s t i n Complex Mix tu re
FIGURE 15
P l a t e 201E7
250X Oxalic
Heat FV 19B
Weld Heat A f f e c t e d >!one A f t e r
T e s t i n 1 3 M "03 - .50M H F
.... ... .... ........ ...... . . . ......... - - . . . ~ , i __I--. -__._ ~
.. .- &-- ._
i; b
FIGURE 16
P l a t e 201E8
250X Oxalic
Heat FVll
Weld Heat Af fec t ed Zone A f t e r
T e s t i n 1x1 "03. - .50M HF
FIGURE 17
P l a t e 201E4
250X Oxal ic
Heat FV71
Weld Heat Af fec t ed Zone A f t e r
Test i n 1% HNO3 - .50M HF
. . . . . . . . . ........ . .... _ ._.. _. . . . . . . . . ........ .......... . . . . . . . . . . . . --
I .
FIGURE 18
P l a t e 201E5
250X Oxalic
Heat FV79
Weld Heat Affec ted Zone A f t e r
T e s t i n 1 3 M "03 - .50M HF
FIGURE 13
P l a t e 201E6
250X Oxalic
Weld in Heat FV79 A f t e r
T e s t i n 1% "03 - .50M HF
- TABLE X I 1 --
METALLOGRAPH1.C EXAMINATION OF WELDED 1 / 4 " PLATE SAMPLES
HN03-HF TESTS
Heat Affec ted Zone --- Heat No. Weld Metal Area Next t o Weld Area -1/8" from Weld
FV 19B A l l a u s t e n i t i c No p r e c i p i t a t i o n ca rb ides Some discont inuous p r e c i p i t a t i o n
F v l l P o s s i b l e t r a c e of f e r r i t e No p r e c i p i t a t i o n
FV 19A A l l a u s t e n i t e N O p r e c i p i t a t i o n
F V 7 1 Cons iderable f e r r i t e -30% f e r r i t - e i n base metal
Continuous pr ec i p i t a t ion ca rb ides - i n t e rg ranu la r at- t a c k
S l i g h t amount discont inuous prec i p i t a t ion
-30% f e r r i t e , prnbably p r e c i p i t a - t i o n a long f e r r i t e a u s t e n i t e
Fv 56 A l l a u s t e n i t e No p r ec i p i t a t ion No p r e c i p i t a t i o n
FY79 -5% f e r r i t e Trace of f e r r i t e with p r e c i p i t a t i o n along f e r r i t e - a u s t e n i t e boundaries
Trace of f e r r i t e with p r e c i p i t a t i o n along f e r r i t e - a u s t e n i t e boundaries
W cn
Page 37
The microexamination of weld co r ros ion t e s t specimens has revea led t h e fo l lowing
s i g n i f i c a n t conclus ions .
1. Although t h e HN03-HF s o l u t i o n s a r e h ighly c o r r o s i v e i n n a t u r e they do not
produce i n t e r g r a n u l a r a t t a c k except: where a continuous g r a i n boundary p rec ip i t . a t e
i s p re sen t .
2 . I n c o n t r a s t t h e complex s o l u t i o n appears capable of caus ing i n t e r g r a n u l a r
e tch ing ( o f a s u p e r f i c i a l na tu re l e s s than a g r a i n deep) of t h e a u s t e n i t e s t r u c t u r e s
even i n t h e absence of a v i s i b l e g ra in boundary p r e c i p i t a t e ; i t does not do t h i s
with duplex s t r u c t u r e s . The i n v i s i b l e p r e c i p i t a t e o r g ra in boundary cond i t ion appears
t o be more seve re wi th higher annea l ing temperatures . Th i s could exp la in t h e l o c a t i o n
of apprec i ab le i n t e r g r a n u l a r a t t a c k immediately a t t h e edge of weld fus ion zones i n
Type 309L o r 309 Cb m a t e r i a l s which extends an apprec i ab le d i s t a n c e i n t o t h e base
metal , d iminish ing i n i n t e n s i t y a s t he d i s t a n c e inc reases . Such a t t a c k does not
i
I
occur i n a sharp , deep l i n e , l i k e t h e so -ca l l ed k n i f e - l i n e a t t a c k seen with welded
and s e n s i t i z e d Type 347 or Type 309 Cb. This apprec i ab le band a t t a c k next t o the
fus ion zone does not occur on any o f t h e Type 310 compositions included i n t h i s pro-
gram.
3. With t h e except ion of t he 30 Cr-25 N i Heat F V l l t h a t had cont inuous g r a i n
boundary p r e c i p i t a t e , microscopic examination a f t e r t h e HN03-HF t e s t s a t 250X was
not a b l e t o r e v e a l any i n t e r g r a n u l a r co r ros ion o r g r a i n f a l l - o u t a t t h e surface: of
any compositions included i n t h e program. Even t h e J?V vacuum melted h e a t s showed no
a t t a c k a t t he edge of t he fus ion zone i n HN03-HF, a l though they d e f i n i t e l y were
a t t a c k e d i n t h e complex s o l u t i o n , v i s i b l e on t h e machined ends.
4 . Heat GD44, Type 310 Cb, showed no i n t e r g r a n u l a r a t t a c k i n any of t h e so lu -
t i o n s , e i t h e r i n the a s welded cond i t ion o r a f t e r s e n s i t i z i n g . It i s s u b j e c t , how-
eve r , t o t h e mild s u r f a c e i n t e r g r a n u l a r e t ch s i m i l a r t o a l l t he o t h e r a u s t e n i t i c
compositions, b u t which i s not s e r i o u s .
. .. - . .. .. . . . .. ~. .... ~ . . . - . . . . .. . . ., ..
Page 38
5 . There i s no explana t ion (no s t r u c t u r a l p e c u l i a r i t y ) why Type 309 Cb welds
a r e s u b j e c t t o s eve re d e t e r i o r a t i o n i n b o i l i n g "03-HF s o l u t i o n s b u t unaf fec ted by
t h e complex s o l u t i o n . The Type 310 Cb weld was unaf fec ted by e i t h e r s o l u t i o n .
6. I n those in s t ances where t h e HNO3-HF s o l u t i o n produces a n apparent gray
e t ch i n h e a t a f f e c t e d zones, with t r a c e g ra in boundary p r e c i p i t a t e , t h i s a t t a c k i s
s u p e r f i c i a l (no t more than .001" deep) and i s not i n t e r g r a n u l a r o r graying in n a t u r e .
Conclusions of I n v e s t i g a t i o n :
1. Resu l t s of t h e i n v e s t i g a t i o n i n d i c a t e t h a t .02% carbon Type 310 Cb o r
.02% carbon Type 310 both a r e an improvement over Type 309L and Type 309 Cb i n t h e
n i t r i c - h y d r o f l u o r i c and complex s o l u t i o n s from t h e s tandpoin t of genera l co r ros ion
5 a t e s . A l l of t h e h igh C r - N i a l l o y s show improved c o r r o s i o n r a t e s over both Types
309 and 310 compositions i n HN03-HF s o l u t i o n s , but t h e h igh C r - N i a l l o y s a r e about
comparable t o Type 310 m a t e r i a l s i n t h e complex mixture .
2. A l l of t h e Type 310 a l l o y s , 2 s wel l a s Heat FV11, a 30 Cr-25 N i a l l o y ,
a r e f u l l y a u s t e n i t i c . Corrosion r a t e s i n any of t h e environments does not appear
t o be a f f e c t e d by t h e presence o r absence of f e r r i t e ; r a t h e r i n s t ead t h e i r a l l o y
con ten t has a dominant i n f luence , with chromium being s t r o n g e s t and n i c k e l less , .
Only i n 6% FeC13 does f e r r i t e appear t o have an in f luence i n promoting p i t t i n g .
3 . S i l i c o n and manganese v a r i a t i o n s have perhaps s l i g h t e f f e c t on co r ros ion
i n t h e va r ious environments, bu t not. s u f f i c i e n t t o cons ider such v a r i a b l e s a s
s u f f i c i e n t t o improve co r ros ion r e s i s t a n c e t o t h e poin t d e s i r e d . High s i l i c o n may
be a disadvantage i n 65% "03.
4 . I n weld t e s t s on p l a t e , co r ros ion t e s t s i n HN03-HF and t h e complex mixture
a r e t h e only ones capable of developing i n t e r g r a n u l a r a t r a c k on t h e a l l o y s i n t h i s
program.
t e n i t i c 30 Cr-25 N i a l l o y (with .084% N) i n t h e h e a t a f f e c t e d zone. The complex
s o l u t i o n showed severe i n t e r g r a n u l a r a t t a c k of t he same Heat FVll and a c c e l e r a t e d
The HN03-HF s o l u t i o n caused d e f i n i t e i n t e r g r a n u l a r a t t a c k of FVll t h e aus-
. . . . . . . . . . . . . . . . . . - . . - - . - . - . - -
Page 39
a t t a c k a t t h e edge of t h e fus ion zone on Heats RV294, RV297, FY79, a l l Type 309 o r
309 Cb h e a t s .
5 . Light gray e t ch ing by "03-HF s o l u t i o n s i n heaiz a f f e c t e d zones of Heats
FY78 ( .02% carbon Type 309), and t h e fo l lowing Type 310 h e a t s , F V 1 7 A y FV19Ay FY19B,
and FV56, was very s u p e r f i c i a l and d e f i n i t e l y not i n t e r g r a n u l a r i n na tu re .
6 . Severe weld a t t a c k of Type 309 Cb occurs i n "03-HF but no t t h e complex
s o l u t i o n .
7 . The complex mixture produces a s u p e r f i c i a l i n t e r g r a n u l a r e t ch a t g r a i n
boundaries i n a u s t e n i t i c s t r u c t u r e s v i s i b l e a t 30X even i n t h e f u l l y annealed condi-
t i o n when no g ra in boundary p r e c i p i t a t e can be seen. The a t t a c k appears t o be worse
y i t h h ighe r annea l ing temperatures .
an i n t e r e s t i n g phenomenon t o i n v e s t i g a t e .
The mechanisms . a r e not understood and would be
8. It has been demonstrated t h a t a n improved co r ros ion r e s i s t a n t a l l o y lover
Type 309L and Type 309 Cb has been a t t a i n e d i n t h i s i n v e s t i g a t i o n .
.02% carbon Type 310 Cb, o f f e r s t h e b e s t promise among t h e Type 310
It shows much b e t t e r co r ros ion rate:; i n b o i l i n g HN03-HF and complex
Types 309L o r 309 Cb, and i s not s u b j e c t t o i n t e r g r a n u l a r a t t a c k i n
Heat G D 4 4 , t h e
compositioins.
s o l u t i o n s than
weld h e a t a f f e c t e d
zones i n any of t h e environments. This a l l o y i s f u l l y a u s t e n i t i c and demonstrated it
could, on a l abora to ry s c a l e , be hot: f i n i s h e d and co ld f i n i s h e d s a t i s f a c t o r i l y t o
p l a t e and s h e e t .
u n l i k e Type 309 Cb, showed no a c c e l e r a t e d co r ros ion of t h e weld depos i t .
It welded s a t i s f a c t o r i l y wi th f i l l e r of t h e same composition, and,
9 . Because of t h e i r even bett :er co r ros ion r e s i s t a n c e , t h e high C r - N i al i .oys
o f f e r p o s s i b l e f u t u r e promise. They a re duplex s t r u c t u r e s (except f o r Heat FV11, a
30 Cr-25 N i a l l o y with .084% N) and a s such would be very d i f f i c u l t t o process i n t o
va r ious wrought forms. The encouragement provided by hea t FVll i s overshadowed by
i t s i n t e r g r a n u l a r s u s c e p t i b i l i t y . More should b e learned about t h e e f f e c t s of carbon
and n i t r o g e n i n t h e s e h igher a l l o y s i n regard t o s i n g l e phase s t r u c t u r e and i n t e r -
Page 40
granu la r s u s c e p t i b i l i t y , i n view of t h e i r ve ry low c o r r o s i o n r a t e s .
W. C. Renshaw Allegheny Ludlum S t e e l Corpora t ion
Research Center Brackenridge, Pennsylvania
WGR : ga
October 23, 1962
Q I
H e a t No. -- FV-70
I 1
1 1
I 1
FV-19B I 1
I I
I 1
ly-11 I 1
I I
II
FV-19A I 1
I 1
I 1
Fv-20 I1
I 1
I 1
FV-17A I I
1 1
I I
Fv-71 I1
1 1
I 1
FV-56 I I
I 1
I 1
, FV-57
Ann ea 1 ed a %
2050°F 2050 2 150 2 150
2050°F 2050 2150 2 150
2050°F 2050 2 150 2 150
2050°F 2050 2 150 2 150
2050°F 2050 2150 2 150
2050°F 2050 2150 2150 '
2050°F 2050 2 150 2150
2050°F 20 50 2 150 2150
2050°F 2050 2 150 2150
TABLE A-1 - -- CORROSION RESULTS I N B O I L I N G SOLUTIONS
OF 13M HNO3 $. .075M HF
ON SHEET (SfX 24 HOUR P&RIObS)
A Corrosion Rate IPM 1
.0187
.0182
.0190
.0193
.0212
.0202
.0241
.0241
.0127
. 0 124
.0072
.0226
.0211
.0215
.0245
.0242
.0141
.0136
.0184
.0190
.0237
.0239
.0359
.0360
,0133 .0163 .0150 .0145
.0244 ,0192 .0264 .0247
.0183
.0177
.0206
.0220
2
. 0 165
.0165
.01'76
.01'79
. 0 182
.0171
. O N 7
. 0 148
.011.7
. 0 11.5
.0103
.0102
.0148
.0149
.0075
.0176
.0134
.0134
.0134
.0131
.0237
.0246
.0301
.0301
.0074
.0088
.0128
.0122
.0185
.0146
.0187
.0172
.0151
.014 1
. O l O l S
.0113
-- 3 4
.0182
.0185
.0159 0164
.0174
. 0 163
.0150
.0152
.0107
. 01.09
.0086
.0084
.0181
. 0 1.84
.0144
.OM4
.0135
.0134
.0130
.0132
.0244
.0245
.0284
.0284
.0117
.0138
.0131
.0125
.0220
.0173
.0208
.0192
.0169 0157
.0161
.0174
.0168
.0170
.0168 ,0172
.0173
.0163
.0182 : .OL84
.0083
.0076
.0108
.0107
.0130
.0134
.0129
.0129
.0096
.0096
.0132
.0126
.0186
.0241
.0286
.0287
.0110
.0130
.0134
.0128
.0204
.0160
.0187 0173
.0148
.0138
.0159
.0172
5
.0179
.0181
.0172
.0178
.0166
.0156
.0181
.0181
.0108 ,0105 .0079 .0079
.0120
.0122
.0153
.0153
.0120
.0117
.0115
.0114
.0255
.0219
.0266
.0266
.0103
.0122
.0115
.0109
,0186 .0124 .0136 .0126
.0156
.0144
.0145
.0157
6
.0163
.0164
.0176 ,0182
.0124
.011.6
.0168
.0168
.0073
.0072 ,0075 .0070
,0094 .0096 .0135 .0139
.0063
.0062
.0093
.0091
.0174
.0187
.0296
.0301
.0086
.0103
.0105
. 0100
.0150
.0118
.0136
.0125
.0077
.0113
.0195
.0212
- ilvg,
.0174
.0175
.0174
.0178
.0172
.0162
.0178
.[I179
, 0103 . C I l O O .0087 .0111
.0147
.O 150
.0164
.0164
.0115
.0113
.0131
.0131
.0222
.0230
.0299
.0300
.0104
.0124 '1 0127 .0122
.0198
. 0 152
. O 186
. 0 173
. o L47 -0145 .0:162 .o:t75
.. . . ., .... _.._. -- . . . .. . .. . ~ .. . ... . .. ... . . . -.. .- . . . . - . . . . . . . . , - .
U -..
Heat No. Y FY-78
I t
1 1
I1
RV-296 I 1
I 1
I 1
RV-294 I 1
11
I 1
RV-297 I 1
I 11
FY-79 I 1
I 1
I 1
GD-44 I 1
I 1
I 1
Annea led a t
2056°F 2,050 2 150 2150
2050'F 2050 2 150 2 150
2050°F 2050 2 150 2 150
2050°F 2050 2150 2 150
2050°F 2050 2 150 2150
2050°F 2050 2 150 2150
-- TABLE A - 1 ( c o n t d )
Corros ion R a t e IPM 7 - c L
.0206
.0206
.0304
.0299
.0277
.0285
.0308
.0308
.0277
.0278
.0288
.0287
.0267
.0272
.0233
.0240
.0285 ,0275 .0236 .0239
.0171
. 0 1 7 7 ,0173 .0175
.0291
.0287
.0300
.02!30
.0262
.0270
.0271
.0272
.0251
.0255
.0205
.0203
.0161
.ole12
.021.0
.0209
.0262
.026 1
.023@
.0228
.0151
.0153
.0138
.0139
3
.0317
.0313
.0248
.0329
.0216
.0224
.0218 -0220
.0167
.0168
.0209
.0206
.0221
.0221
.0164
.0164
.0250
.0249
.0358
.0137
.0124
.0126
.0112
.0154
4
.0275
.0272
.0202
.0195
.0183
.0189
.0154
.0155
.0158
.0159
.0163
.0160
.0176
.0176
.0176
.0146
.0195
.0194
.0184
.0188
.0121
.0123
.0129
.0129
- J
.0238
.0235
.0153
.0146
.0131
. 0 136
.0175
.0177
.0168
.0169
.0x3
.0181
.0182
.0182
.0147
.0171
.0248
.0248
.0224
.0228
.0128
.0129
.0128
.0128
.0210 .I3256
.0207 .0e3
.0143 . (3225
.0137 .0233
.0117 .(I198
.0121 ' .020Lr
.0120 .0208
.0121 .(I209
.0122 .019 1
.0124 " 0192
.0128 a 0196
.0125 . .0194
.0125 .0189
.0125 .0190
.0150 . 0180
.0174 .0184
.0124
.912,5 ,0122 .0125
.0089
.0090
.0082
.0082
.0227
.022.5
.0226
.0191
.Q131
.0133
.0127
.0135
. -
Hear N O .
ET-70 I 1
I 1
I 1
1 1
I 1
FV-19B I 1
I 1
1 1
1 1
I 1 1
FV- 11 11
II
I 1
S I
I 1
FV - 19A I 1
I 1
I 1
1 1
I 1
m - 2 0 1 1
I 1
II
I 1
I 1
FV -17A I 1
I 1
I 1
I 1
I I
~~
Annea l e d a t
2050°F 2050 2150 2 150 2300 2300
2050'F 2050 2150 2 150 2300 2300
2050°F 2050 2 150 2 150 2300 2300
2050°F 20 50 2150 2 150 2300 2300
2050'F 2050 2 150 2 150 2300 2300
2050°F 2050 2 150 2 150 2300 2300
TABLE A-2 -- CORROSION RESULTS IN BOILING SOLUTIONS
OF 13M HNO3 t- 25M H F
ON SHEET ( S I X 2sc HOUR PERLOBS)
C o r r o s i o n R a t e IPM 1
.0437
.0439
.0328
.0326
.0542 ,0520
.0413
.0420
.0468
.0489
.0457
.0468
.0319
.0321
.0345
.0352
.0307
.0314
.0955
.0084
.0484 ,0477 .0291 .0702
.0144
.0145
.0321
.0313
.0296
.0284
.0608
.0615
.0626
.0613
.0527
.0518
2
.0335
.0341
.0376
.0382 0363
.0365
.0668
.0674
. 0 743 -0771 .03?7 .0328
.0202
.0203
.0102
.0103
.0358
.0359
.0480
.0460
.0369
.036 1
. 0 14.1
. 0 135
.0557
.0444
.0441
.0263
.0254
.0599
.0602
.0712 ,0698 .0884 .0877
----
.0551 *
3
.0373
.0382
.0335
.0339
.0350
.0352
.0262
.0264
.0301
.0312
.0374
.0388
.0282
.0283
.0204 I 0205 .0175 .0177
.0342
.0330
.0431
.0422
.0669
.0368
.0199
.019 7
.0169
.0168
.0194
.0187
.0370 * 0401 .0947 .0965 .0371 .0341
4
.0596
.0612
.0294
.0298
.0419
.0420
.0983
.1000
.0816
.0741
.0569
. os90
.0259
.0260
.0658
.0254
.0235
.0238
.0335
.0322
.0511
.0429
.0481
.0463
.0231
.0229
.0394
.039 1
.0295 ,0285
.0746
.0765
.0613
.0607
.0579
.0571
5
.0269
.0272
.0405
.0411
.0465
.0468
.0435
.0439
.0286
.029 7
.0368
.0384
.0299
.0301
.0240
.0242
.0227
.0221
.0380
.0367
.0313
.0378
.0739
.0712
.0437
.0434
.0437
.0433
.0380
.0368
.0689
.0693
.0876
.0872 ,0764 ,0755
6
.0194
.019 7
.0281
.0285
.0379
.0382
.0322
.0327
.0279
.0290
.0623
.0647
.0357'
.0361
.0224 = 0226 .0349 .0353
.0316
.0306
.0503
.049 1
.0356
.0343
.,0338
.0333
.0265
.0344
.0367
.0355
stopped 11
11
II
I I
I t
.0367
.0374
.0337
.0340
.0420
.0418
.0514
.0521
.1466
.0483
.0451
.0468
.0285
.0288
.0296
.0230
.0275
.027 7
.0468
.O3 12
. 0435
.0426
.0446 ,0454
.0318
.0315
.0338
.0348
.0299
.0289
.0602
.0615
.0755
.0751
.0625
.0612
0 a Heat No. Annea l ed
a t
2Q5Q"F 2050 2,150 2 150 2300 2300
2050°F 2050 2 150 2 150 2300 2300
2050°F 2050 2 150 2 150 2300 2300
2050°F 2050 2 150 2 150 2300 2300
2050°F 2050 2150 2150 2300 2300
2050°F 2050 2 150 2 150 2300 2300
2050°F 2050 2150 2150 2300 2300
(contd)
C o r r o s i o n Ra te IPM 1
.0192
.0201
.0208
.0194
.0263
.0242
.0472
.0457
.0468
.0482
.0511
.0624
,0462 .0431 .OM5 .0410 .0381 .0389
.0416
.0421
.0322
.0334
.0361
.0363
,0419 .0429 .039 7 .0406 .0338 .0341
.0401
.0390
.0788
.0771 ,0352 .0354
.0436
.0441
.0397
.0415
.0320
.0322
2
i 8299 .0317 . 0 1'3 1 . 0181 "0269 . .02!J5
.0343
.03:34
.039 1
.0402 0468
.0648
.059 1
.0589
.0214
.0176
.0177
.122Lc
.1214
.0248
.025 1
.0249
.02&9
.0245
.0246
.0605
.0600
.0233
.0233
.0656
.0643
.0591
.059 2
.!I584
.0603
.0721+
. p 725
.04 79
.0488
.0654
.0653
--
.021.1 "
3
e 84RX 0 0514 .0464 .044 3 " 0 2 0 3 0192
.0687
.(I696
.0775 e 0874 .0358 .0528
0313 . 0 2 9 9 .0494 .8499 .0414 .0414
.0657
.0659 ,0616 .0632 .048 1 .0482
.0876
.0892
.0483
.0480
.0447
.0452
.0428
.0421
.0738
.0735
.0651
.0667
.0549
.0544 0672
,0686 .0663 ,0662
4
Q434 .0h60 .039 7 .0378 . c201. .0192
.0292
.0284
.0218
. 0 2 m
.0458
.0667
.0485
.0472
.0474
. 0 9 2
.0289
.13289
5
8358 .0371 .0278 .0264 e 0281 .0270
.0410
.0396 ,0689 0690
.0452
.0394
a 0271 .0263 .0459 .0466 .0461 .0463
stopped 11 stopped 11
.0635 .0687
.0750 .0690
.0637 .0693
.0641 .0631
.Of337 .0583
.0648 .0592
.0579 .0563
.0573 .0561 ,0596 .0601 ,0599 .0603
.0696 .0790
.0685 .0605 stopped 11 ' stopped
.0645 .05 73
.0662 .0589
1 1
.0528 .0644
.0526 .0641
.0620 .0.583
.06.56 .0574
.0630 .0581
.0632 .0582
6 Avg.
I 8 2 6 2 II 0 3 3 6 .0281 .io357 .0321 .'3310 .0305 .(I294 0335 .0259
.0324 .0246
.0482 .0448
.0458 .0438
.0340 e 0480
.!I340 e 050 1
.0435 .044 7
.0493 .0559
.0554 . .0448
.0550 .0434
.0436 .04 13
.0443 e04 19
.0322. ,034 1
. 0 3 2 3 , .0343
stopped .0765 .0765
.0682 .053 2
.0686 .0557
.0580 .0517
.0680 .0507
11
.0616 .0563
.0622 .0572
.0489 .05 19
.0489 .05 18
.0625 .0473
.0626 .0476
.0596 .0595
.0583 .0.555 stopped 11 .0706
0699 .0541 .0.558 .0564 .0573
.0635 .0586
.0632 .0585
.0548 .054 1
.0469 .0548
.0319 .0528
.0406 .0543
. .. . . . .. .~. . - .. .~ . . . . . , . . ,._ _ . . ~ . " . . . . . - . . , . . . ... .
Heat No.
FV-70 I 1
I 1
I 1
FV - 19B I 1
I I
I 1
FV-11 I
1 1
I 1
FV - 19A 1 1
FV - 20 I I
~ - 1 7 A I !
I I
I I
FV-71 I I
I 1
1 1
FV-56 1 1
1 1
1 1
FV-57 I 1
I I
1 1
Annea led a t
2050°F 2050 2 150 2 150
2050°F 2050 2 150 2 150
2050°F 2050 2150 2 150
2050°F 2050
2050'F 2050
2050'F 2050 2 150 2 150
2050°F 2050 2 150 2 150
2050'F 2050 2 150 2150
2050°F 2050 2 150 2 150
2050°F 2050 2 150 2 150
--
TABLE A - 3 -- CORROSION RESULTS I N R O I L I N G SO1,UTIONS
of 13M HNO3 -!- .50M HI:
ON SHEET (SIX 24 HOUR PERIODS)
Cprros ion Rate 1.E" c) 1
.0772
.0694
.0689
.0671
. lo26
. 1.020
.0844
.0852
.066 7
.0672
.0532 ,0541
.0407
.0420
.0244
.0236
.0454
.0513
.0973
.0984
.0203
.0211
.0286
.0272
.0627
.0899
.0865
.0655
.0911
.0905
.0893
.0906
.1197
.1200
.1178
.1212
L -- .0652 .0668 .0405 . 0395
.0968
.0959
.07:31 ,0738
.07:11
.07;,3
.025 7
.0267
.0355
.0370
.0398
.0388
.084 1
.0844
.0653
.0655
.032.5
.0337
.0288
.0270
.0692
.0373
.0388
.0732
.0712
.0874
.0884
. 1652
.1645
.0612
.0624
.ob87
3
.0353
.0438
.0526
.0509
.0469
.0466
.0505
.0505
.0330
.0339
.0373
.0385
.0512 - 0533
.039 7
.0387
.066 1
.0671
. l o 6 7 ,1072
,0355 .0371 .0424 .0394
.0668
.0659
.0708
4
.0279
.0285
.0266
.0258
.I3296
.0294
.0347
.0349
.0198
. (3201
.0298
.0307
.0453
.0473
.0636 *
.0615
.0532
.0619
. 1.320
.1326
.039 1 -0408 .0628 .0585
.0925
.0911
.0693
5
.0575
.0589
.0683
.0665
.0604
.0598
.05 76
.0582
.0427
.0434
.!I540
.0558
.0575
.0602
.0322
.0317
.0858
.0936
.0865
.0872
.0379
.0395
.0477
.0446
.0447
.0440
.0363 .0720 ' .0689 .0364
.0844 .0765 .0805
.0812 . 0 733 .0769
.0543 .0483 .0796
. OS55 .0495 .0812
.0728 .0711 .0900
.0729 .0703 .OB98
.1250 s topped stopped
6
.0405
.0415
.0348
.0338
.(I381
.0379 I 0458 .0467
.0299
.0304
.0320
.0329
. O e . i O
.0841
.0526
.0515
.0846
.0918 s E opp ed
1 1
.0586
.0513
.'0516
.0484
.0772
.0758
.0749
.0748
.0496
.0875
.0573 0586
.1089
.1096 stopped .~ .~
.1259 excess ive . weight l o s s end g r a i n a t t a c k
1\17 e 0
.13506 ,125 15 . Oh86 . oLc73
.0621
. (If8 1 9
.0577 0582
.0439 ,0446 .(I38 7 .0398
.0519
.0540
.042 1
.04?0
.0699
.0750
. 09 76
.0982
.0373 e 0373 ,0437 .0409
.0689
.0726 0625 0594
.0759
.073&
.0b94 e 0706
. 1.046 0 1045 .1013 . 1.032
_i-
Heat No.
RV-296 I 1
I 1
I 1
RV-294 1 1
I 1
I 1
RV-29 7 I1
I 1
I 1
N- 79 1 1
1 1 ' I t
GD-44 I 1
1 1
I 1
Annealed a t --
20.50°F 2050 2150 2 150
2050°F 2050 2 150 2 150
2050°F 2050 2 150 2 150
2050°F 2050 2 150 2 150
2050°F 2050 2150 2 150
TABLE A - 3 -- -
Corros ion Rat.e IPM 1
,1139 .1118 .1124 .1125
.LO36
. 1037
. 1105
.lo95
.0014
.0016 fog91 .099 1
.1265
.1257
.0968
.0974
,0943 .0937 .0716 .0725
2
,1111 .lo96 .0705 .0698
. 0 752
. 0 79 2
.1548
.1522
.06 75
.0685
.07:?7
. 0 724
. 1299
. 1305
. 1139
. 1154
.0555
.0554
.0735
.0755
-- 3 4
.0716 I 0596
.0708 .0553
.LO72 .0638
.lo50 .0631
I 0616 .0612 .0764 .0742
* 12.1.5 . 121.9 .1339 .1348
.0605
.Oh05
. 1.063
.lo46
. 1.624
. 1.645
.0661
.0666
. 1206 stopped
.1209
.(I693 .OB93
.0692 ,0903
I 1
.0593 .(I470
.0592 .0467
.0910 .0789
.0933 .0809
5
. 1062
.1075
.0786
.0773
.1104 1108 ,0874 .0866
.0842
.0859
.0885
.0889
stopped
. 1004
.1007
.0555
.0554 a 0623 ,0635
11
.1003 , 0 9 3 1. 0 1011 .0927 .1108 f093h .1106 . os9 7 .i068 0869 .i064 '08 70 . 1039 . !Ob6 . 1.042 e 1,052
.0725 .08&9
.0735 . (3860
.0761. .0894
.0762 .O89 7
stopped . 1257 e 1-257
.09 16 .0936
.0917 .094 1
11
e 0730 .(I641 .0729 .(I639 :0679 .07&2 .0693 .0758
Heat NO.
N-70 II
N-19B II
N-11 11
EV-19A II
N-20 11
N - 1 7 A II
EV-71 11
FV-56 11
N-57 It
W-78 I1
RV-296 II
RV-294 I 1
RV-297 11
FI-79 II
GD-44 I I
E_r
1st
.004 12 ,00466
.00513
.00465
.00338 ,00367
.00392 ,00374
.00350
.00347
.00459 -00446
.00292
.00268
.00430
.00367
.00310
.00374
,00060 .00048
.0044 6
.00432
.00089 -00089
-00380 .00376
.00330
.00406
.00059
.00058
n
2nd
.00282
.00279
.00300
.00296
.00205
.00207
.00262
.00254
.00211 * 00210
.00252 -00254
.00209
.00203
.00253
.00261
.00258
.00304
.00333
.00318
.00566
.00584
.00376
.003 70
.00610
.00658
.00406
.00439
-00292 .00292
1 I pj' p i i l l hl &Jl pEI1
TABLE A-4 -- CORROSION RATES I N BOILING COMPLEX MIXTURE
OF 6M "03 + .4M H2SO4 + .4M NaN03
+ . 3M Fe2(S0$)3 + .OM C r + .OM Hg + .Om PO4
3r d
.00368
.00360
.00309
.00308
.00229
.00241
,00259 .00252
.00218
.00272
.00288
.00287
.00302
.00318
.00263
.00282
.002 74
.00310
.00443
.00449
.00737
.00762
.00577
.00579
.00658
.OO 709
.00509
.00552
.00331
.00330
ON SHEET ANNEALED 2050°F Rates i n Inches per Month
4 t h
.00339
.00329
.00267
.00271
.002 13
.00220
.00233
.00228
.00260
.00263
.00245
.00246
.00286
.00304
.00224
.00242
.00233
.00257
.00500
.00530
. 00 722
.00736
.00678
.00679
.00807
.00863
.00481
.005 12
.00368
.00375
5 th
,0040 1 .00390
.00322
.00326
.00290 -00295
.00277
.00271
-00311 .00317
.00293
.00295
.00345 ~ 00372
.00256
.00275
.00278
.0029 7
.00486
.00522
.00722
.007 36
.006 l l
.00622
.00780
.00521
.004ai
.005 12
.00302
.00319
.
6 th
.00350
.00341
.00287
.00293
.00274
.00277
.00249
.00240
-00292 .00296
.00271
.002 74
.00319
.00346
.00241
.00253
.00249
.00257
.00580
.00629
.00859
.00867
.00566
.00590
.00780
.00825
.00569
.00602
.00331
.00339
7th
.00458
.00396
.00328
.00336
.00342
.00340
.00293
.00287
.00343
.00342
.00308
.002a5
.00363
.00395
.00264
.00268
.00220
.00221
.00637
.00685
.00927 ,00923
.00755
.00784
.00938
.009 69
.00592
.00628
.00375
.00254
8 t h
.00359
.00396
.00326
.00340
.00377
.00256
-00308 .00299
.00354
.00358
.00323 ,00351
.00368
.0040 1
.002 78
.00275
.00280
.00267
.00865
.00923
.00892
.00877
.00957
.00434
.00994
.00015
-00585 .00623
.0049 3
.00513
9 t h
.00401
.0038 7
.00336
.00345
.00386
.003 74
.00314
.00305
.00353 -00355
.00316 00321
.00370 -00403
.00288
.00282
.00302
.00273
.00817
.00845
.00971
.009 64
.00892
.00909
.00681 -00694
.006 19
.00624
.004 70
.00483
10th
.00439
.00434
.00349 ,00353
.00334
.00430
.00342
.00333
.00390
.00394
.00361
.00365
.00389
.00423
.00309
.00289
.00315
.00276
.00885
.00936
,009 14 .00894
.00927
.009 74
.00954
.00961
.0058 1
.00604
.005 18
.00539
Avg.
.0010
.003Z 7
.00333
. 00333 ,00298 .003no
.002@8
.002%A
. oomt
.003115
.003BL
.003U
.00324
.003&3
.00280
.00259
.00271
.002B3
.005Qo
.00588
.00775
.00737
.00642
.00603
.007%3
.005&3
.005115
.005x)
.00353
.003M)
Heat No.
FV-70 I t
EV-19B I t
Fv-11 I t
M-19A I t
Fv-20 tt
FV-17A I t
m-71 $1
FV-$6 I1
Fv-57 I t
Fy-78 v 1.
RV-296 It
RV-294 I t
RV-297 I 1
F-f-79 I t
GD-44 I t
1 s t
.00444
.004 19
.00435
.0039 7
.00355
.00337
.00381
.00411
.00399
.00354
.0043 1
.00388
.00290
.00292
.00449
.00450
.00395
.00433
-00382 .004 10
.00424
.00439
,00452 .00449
.00466
.00444
.00428
.00407
.00359
.00330
2nd
.00368
.00383
-00306 .00291
.00230
.00231
.00352
.00361
.00308
.00292
.00310
.00314
.00303
.00293
.0034 1
.00337
.00315
.00290
.00429
.00437
.00539
.00563
.005 59
.00571
.00536
.PO527
.00426
.00405
.00346
.00342
1 m @~C~AB- CORROSION RATES LN BOILING
OF 6M HNO3 t .4M H2SO4
COMPLEX MIXTURE
+ .4M NaN33
+ .3M Fez ( S o 4 ) 3 + .OM Cr'+ .OD1 Hg + .OM PO4
ON SHEET ANNEALED AT 2150°F
INCHES PENETRATION PER MONTH
3rd
.00338
.00347
.00260 ,0025 7
.00204
.00205
.00291
.00299
.00277
.002 74
.00262
.00271
.0029 5
.00286
.00288
.00286
.00275
.00267
.00378
.00385
-00607 .00659
-0059 1 .00605
.00645
.00633
-00466 .00439
.00327
.00332
4 th
.00455
.0046 1
.00311 -0030 7
.00256
.00262
.00359
.00362
.00373
.0039 1
.00317
.00324
.0038 1
.00370
.00335
.00338
.00307
.00307
.00569
.00558
.00828
.00879
.00812
.00817
-00757 .00?54
.0048?
.00454
.00365
.00371
5 t h
.00371
.00373
.00250
.00249
.00213
.00219
.00288
.00289
.00315
.00339
.00259
.00268
.00305
.00298
.00274
.00268
.00252
.00251
.00472
.00451
.00802
-
.ooa79
.00750
.00759
.00723
. nn9?8
.00454
.0042U
.00303
.00314
6 t h
.00443
.00448
.00289
.00286
.00271
.00281
.00331
.00327
.0039 6
.00411
.00306
.00320
.00405
.00393
.00289
.00288
.0029 7
.00296
.00655
.00628
-00954 . 0 1034
.009 12
.009 14
.00840
.0!?5?5
.00554
.00513
.00348
.00385
7 t h
.00346 -00351
-00230 .00230
.00225 .. 00236
.0034 1 -00332
.00368
.00386
.00282
.00298
.00360
.00361
.00268
.00268
.00263
.00261
.006 72
.00639
.01367
.00856
.ooaai
.ooa46
.00899
.GO843
.01086
.00492
.00351
.00336
8 t h
.00421
.00423
.00278
.00287
.00273
.00287
.00288
.00291:
.00377
.00402
.00281
.00298
.00357
.00331
.00252
.00258
.00261
.00259
.00701
.00671
.01228
.O 1024
.00898
.00901
.00893
.GO902
.00580
.00533
.00375
.003a2
9 t h
.00387
.00390
.00271
.00275
.00273'
.0029 1
.00400
.so394
.0048 1
.00524
.00367
.00388
.0044 1
.00423
.00317 -0030 7
.00331
.00324
.00923
.00876
.01109
.01203
.01105
.01103
.01119
.01i i4
.00574
.0069 1
.00489
.00504
10th
,00404 .00408
.00276
.00280
.00288
.00306
.00388
. vv283
.004 74
.00500
.00358
.00382
.00416
.00412
.00313
.00311
.00348
.00334
.00853
.00783
.OL111
.01184
.01061
. 0 1054
nn 7
.oioa4
.01102
.00741
.006a2
.00488
.00499
A v g .
.00398
.00400
.0029 1
.00286
.00259 -00266
.00342
.GO345
.00377
.00387
.00317
.00325
.00355
.00346
-00313 .00311
.00304
.00302
.00603
.00584
.0089?
.008 72
.00802 -0080 7
.00791
.00787
.005ao
.00504
.00375
.00380
Heat No.
FV70-15
FV19 -1 5B
F V l 1 - A
FV 19 - 1 5 A
FV20-15
FV 17- 15A
JW71-15
Temp., 'E
2050
2 150
2300
2050
2150
2300
2050
2150
2300
2050
2150
2300
2050
2 150
2300
2050
2150
2300
2050
2150
2300
COIC3OSION RATES I N - ( d ) B O I L I N G 65X N I T R I C A C I D (FIVE 48 HOUK PERIODS) ( e ) .SM H2S04 AT 200°F ( 2 HOWS) ( f ) 6% FeC13 PITTING TEST
ON SHEET
1st
.0002 3
.00021
.00046
.00045
.00034
.00034
.00043
.00043
.00027
.00024
.00031
.00035
.00035
.00038
.00022
.00023
.00022
.00021
.00027
.00029 -00034 .00031 .00035 .00037
.00035
.00041
.00037
.00037
.00036
.00035
.00040
.00045
.00034
.00038 -00035 .GO034
.00032
.00032
.00037
.00028
.00038
.00039
2nd
.00018
.00017
.00026
.00025
.00025
.00024
.00025
.00034 . 000 19
.00019
.00020 -00016
.00026
.00027
.00017
.00017
.00018
.00017
.00019
.00020
.00028
.00028
.00028
.00028
.00021
.00022
.00020 ,0002 1 .00023 .00023
.00028
.00028
.0002 7
.00030
.00023
.00023
.00021
.00020
.00028
.00016
.00026
.00029
3r d
.00015
.00015
.00021
.00021
.00022 ,00021
.00036
.00035 . 000 14
. 000 14
.00020
.OOO 18
..00021 .00021 .00032 .00015 .00016 .00017
.00017 ,00016 ,00029 .00028 .00030 .00029
.00016
.00018
.00017
.00017
.00016
.00016
.00023
.00023 ,0002 1 .00023 .00019 . ouozo
.00017
.00017
.00021
.00016
.00017
.0002 1
4 t h
.00017
.00017 * 00022 .00022 .00022 .00023
.00037 ,00035 . 000 18 .00018 .00023 .00023
.00023
.00024-
. 000 19 . 000 19
.00018
.00018
.00018
.00018
.00033
.00034
.00035 ,00034
. 000 18 . 000 19
.00017
. 000 19 -00018 .00018
.00027
.00028
.00024
.00026
.00023
.00025
.00017
.00018
.00032
.00017
. 000 19 ,00024
5th
.00017 -00017 .00021 . 000 20 .00023 .00023
.00035
.00035 . 000 18
.00018
.0002s
.00025
.00021
.00023
.00018
.00019
. 000 19
.00019
.00020
.00020
.00034
.00035
.00035
.00034
. 000 15
.00017
. 000 14
. 000 14
.00016 . 000 15,
.00028
.00030 -00026 .00027 .00023 .00024
.00015
.00017 ' .00018
.00013
.00015
. 000 15
Avg. of 5
.00018
.00017
.00027
.00027 '. 00025 .00025
.00037 -00036 -000 19 . 000 19 .00023 .00024
.00025
.0002 7
.00022
. 000 19 . 000 19 -00018
.00020
.00021
.00032 -
.00032
.00033
.00032
.0002 1
.00023
.00021
.00022
.00022
.0002 1
.00029
.00031
.00026
.00029
.00025
.00025
.00020 ,0002 1 .00027 .00018 .00023 .00026
Average- of L 3 , 4 , 5
.00017
.00017
.00023
.00022
.00023
.00023
.00033 -00035 .00017 .00017 .00022 .00021
.00023
.00024
.00022
.00017 . 000 18
.00018
. 000 19
.00019
.00031
.00031
.00032
.00031
.00018 ,00021 .00017 .OOO 18 .00018 .00018
.0002 7
.00027
.00025
.00027
.00022
.00023
. 000 18
.00018
.00025
.00015
.00019
.SM H2S04 2 h r s - 200°F
.42 in/mo
.023 in/mo
.71 i d m o
.ZO inlmo
.IO inlmo
.28 i d m o
.22 inlmo
.30 inlmo
.32 i d m o
.23 in/mo
.26 in/mo
-26 inlmo
.14 in/mo
.26 inlmo
.25 inlmo
. l o inlmo
. 1 7 in/mo
. I7 injmo
.33 inlmo
.32 inlmo
.24 i n l n o
6% PeC13 Room Temperature
. P i t t e d 24 h r s
P i t t e d 24 h r s
P i t t e d 24 h r s
N o p i t s 300 h r s
N o p i t s 300 h r s
N o p i t s 300 hrs
N o p i t s 300 h r s
N o p i t s 300 h r s
N o p i t s 300 h r s
No p i t s 300 hrs
No p i t s 300 h r s
N o p i t s 300 h r s
P i t t e d 100 h r s
P i t t e d 100 h r s
P i t t e d 100 h r s
No p i t s 300 h r s
No p i t s 300 h r s
Nn p i t . 30s hrs
P i t t e d 100 h r s
P i t t e d 100 h r s
Pitted 300 h r s
p e a t No.
M56-15
W57-15
Ff-78
"-296
RV-294
RV-297
FY-79
a-44
- TABLE A-6 ( con td )
65% "03 IPM
Temp. , O F
2050
2150
2300
2050
2150
2300
2050
2 150
2300
2050
2150
2300
2050
2150
2300
2050
2150
2300
2050
2 150
2300
2050
2150
2300
1st
.00040
.00045
.0004 7
.00045
.00053
.00052
.00033
.00031
.00036
.00038
.00039
.00040
.00050
.00033
.00048 :00042 .00044 .00036
.00032
.00031
.00042
.00037 -00041 .00042
.00050
.00045
.00043
.00039
.00038
.00045
fOOO34 .00036 .00044 .OW49 . o o w .OO04 1
.00037
.00036
.00048
.00051
.00044 i m.04 2
.OW24
.00029
.00027
.00031
.00031
.00031
2nd
.00026
.00027
.00025
.00026
.00030
.00029
.00025
.00022
.00027
.0002 7
.00028
.00027
.00015
.0002 7
.00028
.0002P
.00032
.Om31
.00025
.00026
.00032
.00026
.00035
.00034
00033 .00033 .00032 .00031 .00029 .00033
.0002 7 ,00026 .00030 .00032 .00039 .00037
.00028
.00027
.00029
.OO032
.00030
.e0029
.00026
.00024 ,00020 .00022 ,00026 .00027
3rd
.00022
.00023
.00026
.00023
.00016
.00016
.00012
.00014
.00019
.om19
.00021
.00022
.00021
.00017
.00025
.00026 ,00032 .00029
.00022
.00024
.00030
.00026
.00033
.00034
.Oil024
.00025
.00026
.00026 ,00028 .00029
.00020
.00019
.00027
.00029
.00032
.00031
.00026
.00027
.00027
.00028
.00029
.00028
.00021
.00023 I00022 ,00023 ,00024 .00024
4 t h
.00023
.00024
.00025
.00024
.00026
.00026
.00023
.00523
.00026
.00024
.00023
.00024
.00025
.00023
.00024
.00024
.00027 '. 00029 .00022 .OW24 .0002 7 .00024 .00030 .00030
.00024
.00027
.00026
.00026
.00024 ,00026
.00022
.00023
.00025
.00027
.00030
.00030
.00029
.00026
.00028
.00029
.0002 7
.GOO26
.0002 1
.00024
.00026
.00026 ,00029 .00024
5 t h
.00021
.00020
.00020
.00020
.00020
.00019
.00019
.00019
.00018
.00021
.00019
.00020
.00021
.0002 1
.00025
.COO25
.00032
.00025
.00021
.00022
.00029
.00025
.00029
.00030
.00024
.00026
.00025
.00026
.00025
.00026
.00024
.00023
.00024
.00027 -00031 .00031
.00029
.00030
.00029
.00031
.00027
.GOO27
.00021
.00024
.00026
.00026
.00029
.0002 7
Avg. of 5
.00026
.00028
.00029
.00028
.00029
.00028
.00022
.00022
.00025
.00026
.00026
.OW27
.00025
.00024
.00030
. m32;
.00033
.00029
-00024 .00025 .00032 .00028 .00034 .00034
.00031
.00030
.00030
.00028
.00029
.00032
.00025
.00025
.00030
.00033 ,00035
. .00034
,00028 .00029 .00030 ,00034 .00029 .00030
.00023
.00025
.00024
.00026
.00028
.00027
Average of 2, 3, 4, 5
.00023
.00024
.00024
.00023
.00023
.00023
.00020
.00020
.00023
.00023
.00023
.00023
.00021
.ow22
.00026 . GOO26
.00031
.00028
.OO023 -00024 .00030 .OO025 .00032 .00032
.00026
.00026
.00027
.00027
.00027
.00029
.00023
.00023
.00027
.00029
.00033
.00032
.00028
.00028
.O0O2P2
.00030 ,00028 .OUO28
.00024 ,00024 .00024 .00024 .00027 .OW26
.5M &SO4 2 h r s - 200°F
.16 i n h o
.08 inlmo
.18 in/mo
.23 inlmo
.30 in/mo
.23 in/mo
.35 inlmo
.34 inlmo
.34 in/mo
.34 inimo
.36 inlmo
.37 in/mo
.26 in/mo -24 h / m o .23 inlmo .25 inlmo .23 in/mo .23 in/mo
.36 in/mo
.39 inlmo
.28 in/mo
.28 in/mo
.48 in/mo
.42 inlmo
.17 in/mo
.15 inlmo
.21 in/mo
.21 i d m o
.25 in/mo
.25 i n l m o
.26 inlmo
.27 infmo
.26 in/mo
.26 in/mo
.29 i d m o
.28 in/mo
.27 inlmo
.27 inlmo
.29 i n l m o -28 inlolo . 14 injmo .14 Lnlmo
67. FeCl3 Rocrin Temp e ra t ure
No p i t s 300 h r s
P i t t e d 24 h r s
P i t t e d LOO h r s
No p i t s 300 h r s
No p i t s 300 h r s
No p i t s 300 h r s
P i t t e d 56 h r s P i t t e d 144 hrs P i t t e d 168 h r s P i t t e d 168 hrs P i t t e d 144 hrs P i t t e d 144 h r s
P i t t e d 168 hrs P i t t e d 168 h r s P i t t e d 144 h r s P i t t e d 192 h r s P i t t e d 24 hrs P i t t e d 24 hrs
P i t t e d 144 hrs P i t t e d 144 h r s P i t t e d 144 h r s P i t t e d 144 h r s P i t t e d 48 h r s P i t t e d 48 hrs
P i t t e d 168 h r s P i t t e d 168 h r s P i t t e d 144 h r s P i t t e d 144 h r s P i t t e d 24 h r s P i t t e d -24 h r s
OK 300 h r s OK 300 h r a OK 300 h r s OK 300 h r s OK 300 h r s OK 300 h r s
OK 300 h r s OK 300 h r s OK 300 h r s OK 300 h r s OK 300 h r s OK 300 h r s
Heat No.
FV-70
FV-19B
FV-11
FV-19A
Fv-20 I
FV-17A
FV-71
FV-56
Fv-57
FY - 78
RV-296
RV-294
RV-297
FY-79
GD-44
TF.BLE A - 7
B O I L I N G 65% N I T R I C ACID RESULTS
ON S H E E T SAMPLEIS SENSITIZED 1 HOUR AT 1200'F
1~1c.h.e~ P e r Month 1st
.00052
. 00 140
.00082
.0004 1
.00038
.00040
.00049
.00040
.00037
.00044
.0004 1
.00048
.00040
.00042
. 000 58
.00072
.00050
.00051
.00070
.00066
.00086
.00035
.00040
.00044
.00046
.00073
.00043
.00045
.00032
.0003 1
-- 2 nd -- ,00061 .00071
.00039
.00039
.00034
.00036
.00044
.00040
.00037
.00043
.00042
.00044
.00036
.00041
.00046
.00049
.00045
.00044
.00049
.00050
.00054
.00045
.00040
.00044
.00046
.00055
.00043
.00045
.00032
.0003 1
3r d
.00050
.00056
. 00033
.00030
.00030
.00032
.00033
.00068
.00030
.00030
.00036
.00035
.00031
.00035
.00035
.00039
.00035
.00033
.00039
.0004 1
.00045
.OO05 5
.00036
-__I_
. 00036
.00037
.00038
00033 .00033
.00025
.00023
4th
.0005 1 e 00058
.00036
.00034
e 00031 .00031
.00046
.00026
.00030
.00032
.00032
.00033
.00032
.00036
.00036
.00037
.00034
.00034
.00036
.00037
.00040
.0002 i
.00034
.00037
.00038
.00040
.00036
.00037
.00029
.00027
5t:h
.00052 00058
.00034 ,00032
.00034
.00036
.0004 1
.0002 1
.00031
.00033
.00036
.00036
.00033
.00038
.00037
.00039
.00038
.00036
.00036
.00037
.00040
.00036
e 00035 .00037
.00035
.00038
.00037
.00037
.00028
.00027
Avg
.00053
. 000 7 7
.00045
.00035
.00033
.00035
.00043
.00039
.00033
.00036
.00037
.00039
.00034
.00038
.00043
.0004 7
.00040
.00040
.00046
.00046
.00053 ,00038
.00037
.00040
..00040
.00049
.00038
.00039
.00029
.00028
Heat No.
FV-70
FV-19B
Fv-11
FV-19A
Fv-20
FV-17A
FV-71
FV-56
Fv-57
FY- 78
RV-296
RV-294
RV-29 7
FY-79
GD-44
FV-17B
I
1s t
.0208
.0161
.0113
.0167
.0113
.0233
.0280
.0371
.0303
.0432
,0420
.0433
.0383
.0493
6 0190
.0160
TABLE B-1 -- CORROSION RESULTS I N B O I L I N G
OF 13N "03 -t .075M
s OLUTIONS
HF
ON AS WELDED PLATE
Inches P e n e t r a t i o n per Month
2nd
.029 7
.0294
,0211
.0266
.0077
.0191
.0258
.0298
.0282
.0399
.0382
.0363
.0322
,0789
.0285
.0233
3 r d
.02.27
.0207
. 0 144
.021+6
.0177
.0376
.0301
.0331
.024 1
.0284
.0269
.0352
.031.6
.0782
.0286
.0257
-- 4 t h
.0275
.0256
.0161
.0243
.0136
.0290
.0224
.0212
.0295
.0429
.0353
.0396
.0353
s topped
.0292
.0260
5 t h
.0217
.0218
.0211
.0239
. i l l65
.0349
.0219
.0310
.0236
.0364
.0370
.0404
.0332
stopped
.0266
.0231
6 t h
.0290
.0252
.0169
.0169
.0194
.0348
.0260
.0258
.0231
.0343
.036 7
.0351
.0342
stopped
.0268
.0264
Avg .
.0252
.0233
.0168
.0222
. 0 144
.0298
.0257'.
.029 7
.0265
.0375 '
.0361
.0383
.0341
.0688
.0265
.0235
Heat N o .
FV-70
FV- 1 9 B
FV-11
FV - 19A
Fv-20
FV-17A
??I!-71
FV-56
Fv-57
FY- 78
RV-296
RV-294
R V - 2 9 7
FY-79
GD-44
FV-17B
I
1 s t
.0579
.0783
.0427
.0419
.0407
.0846
.0492
.0515
.0510
,0635
.0901
.0735
,0719
.1182
.0493
.0416
-- TABLE B - 2
CORROSION RESULTS I N B O I L I N G SOLUTIONS
OF L;3M #No3 + .25M HF
ON AS WELDED PLATE
Inches P e n e t r a t i o n per Month
2nd -- 3rd 4 t h 5 th 6 t h
.0590 .0460 .0616 .0530 .0486
.0459 .04C19 .0597 .0579 .0528
.0547 .0409 .0449 .0447 .0437
.0352 .0420 .0436 .0342 .0390
.0249 .0343 .0352 .0418 .0355
.0579 .0685 .0809 .0707 .0649
.0408 .0390 .0356 .0438 .0435
.0661 .0442 .0700 .0677 .0556
.0500 .0476 .0572 .0542 * .0401
.0647 .0655 .0992 .0735 * .0680
.09 19 .060.5 .0949 .0756 .0780
.0615 .0540 .0946 .0574 .0662
- 0 5 18 .0739 .0669 .0725 .0800
9
stopped - weld a t t a c k
.0457 .0420 ,049 7 ,0384 .0531
.0720 .0465 .0580 .0788 .0570
Avg.
.0544
.0559
.0453
.0393 '
.0354
.0713
.0420
.0592
.0500
.0724
.0818
.0679
.0695
.0464
.0590
Heat lo e -- Fv-71
FV-17B
Fv - 19A
GD-44
RV-294 I
N - 7 9
FV-70
FV - 19B
RV-297
RV-296
Fv-11
N-78
FY-17A
FY-57
Fv-20
FV-56
1st
.0845
.0909
.0936
.0860
.1579
.1663
.0762
. l o 2 5
.1256
.1357
.0696
.1395
.1269
. l o30
.0755
. l o 6 5
-- TABLE E-3
CORROSION RESULTS I N B O I L I N G S O L U T I O N S
OF 1:3M wN03 4- .50M HP
ON AS WELDED PIA,TE
Inches Pene t r a t ion Per Month
2nd
.0958
.1302
. l o 6 7
. l o 2 3
.1609
.2307
.0928
. l o68
.1308
.1355
.os10
e1198
.1305
. l o o 0
.0854
.1143
3rd
.0945
.1645
--
.0932
. 1066
.1686
.1809
.0943
.0954
.1394
.2170
.0472
. lo14
.0900
.069!3
.04 79
.04 74
a t t a c k
.0461
.0593
.0766
.0696
.OS66
.0926
4 t h 5 t h 6 t h Avg.
“1040 .0513 .0787 .0848
. l o60 s topped-severe ly .1229 a t t acked a t weld end g r a i n a t t a c k
.0696 .0707 .0904 0874
. l o27 .0735 .0826 .0923
.09 73 .0996 .2095 .1490
s topped-weld s e v e r e l y .1926 a t tacked-severe end g r a i n
. 0 744 .1135 .0829
e 1042 s topped- .0936 p i t t i n g type a t t a c k on weld-at tack a t ca rb ide p r e c i p i t a t i o n a r e a s - seve re end g r a i n a t t a c k
.1239 .1364 , 1 2 2 1
.1161 .1259 .1333
s t o p p e d - p i t t i n g .0711 type a t t a c k on w e Id - s ever e a t t ac k a t c a r b i d e p r e c i p i- t a t i o n areas
.1652 .1135 .1220
s topp ed-weld a t t acked- .1158 s p o t t y end g r a i n a t t a c k
.09 72 I 0855 .0931 .09 15
0642 .0941 .0867 .0756
. l o 2 3 .0760 .09 70 .0906
Fea t N O .
EY-70
IFV-19R
FI - 1 14,
FV - 19A
PV-20
EV-17A
FV-71
FV-56
FV-57
~ I _
FY- 78
RV-296
RV-294
RV-297
FY ._ 79
GD-44
FV-17B
1st
- 00375
.00371
.00?.91!
.00323
00043
.00338
.00052
.00304
.00298
. 000 76
. 000 74
.00079
.00074
.00069
.0039 1
.00290
2g.d
00409
.00360
nn3q7
.00321
D 00224
e 00334
.0326 1
.00318
.00306
.00430
.0038 7
.00382
.00417
,00393
.00383
.00298
0 L ."L . - ' ,
a &7 a &--J m; mi a: TABLE B-4 _c_-
CORROSION RATES IN BOILING COP.IPLEX MIXTURE
OF 6M " 0 3 -k .4M ~ 2 S 0 4 -t- .4M NaN03
-1- . 3 M Fe2 (SO/i)3 i- .01M C r -t- . O l M Hg -k .01M PO/,
ON AS WELDED PLATE
Irllches Penetration Per Month
3r d
- 00436
.(I0367
,00236
.0@29 8
.0029 2
.@0312
00353
.00295
.00246
.00143
,00468
,00459
.00460
.0@425
.00340
.00317
-- 4 th
.0049 1
.00376
.00309
.0030F!
. OQ333
.00325
.00365
.00298
.00291
.00889
.00526
.005 1.1
.0054 1
. 00 508
.00350
.00360
5Lh
.00358
- 00322
* 00294
00271
.00300
,00388
00351
e 00247
.00249
.00415
.00430
.00452
.00410
.00438
.00323
.00331
6 t.h
.004 64
.003??
-.-
nn-nn . VV3031
,003 14
.0035 7
.00322
.00330
00262.
.OO29 3
,0046 1
.005 13
.00315
.00513
.00396
.0@342
.0037 7
7 t h
.00460
.00361.
-.-
A n C. n r. uv303
.0030?
00377
a 00317
.00L13
002.42
.@0262
.00524
.00600
.00.541
.0@589
.00506
.Oil351
.00369
8 t h
.00523
.@(I418
.GO465
.00351
.00480
.00362
* 00538
.00271
.00318
.0068Lt
. 00 740
.00717
.0074 1
.00634
.00413
.004 13
9 th.
.00541
.O04 1.8
.00504
.On361
.004 69
.00387
.0051.6
.0026 1
.0@336
.00636
.00662
.006 75
.00679
.00571
.004 13
.00350
10,h
.01)509
.00425
. 0 0 5 i l
--
09164
.00%2
.0037 7
00546 7
,0026 1
.00335
.00@5
.00710
.00730
.00761
. oofio9
. OOQO5
.0039 7
Avg >
2 00460
,00379
. WO36.5
.00322
,00342
I @03/14
e 003 75
.00276
-00290
.00494
.00511
,00486
.00519
.00455
-00371
.0@34 7
Heat No.
Fv-70
lW-19B
Fv-11
N - 19A
Fv-20
N-17A
FV-71
N-56
N-57
FI-78
RV-296
RV-294
RV-297
FY- 79
GD-44
FV-17B
CORROSION TESTS ON AS W E L D E D PLATE W
(d) Boi l ing 65% " 0 3 ( f i v e 48-hour periods) (e) .5M H2S04 a t 200°F ( 2 hour period) ( f ) 6% FeC13 ( p i t t i n g t e s t )
65% " 0 3 IPM
1st
.00050
.00058
.00030
.00027
.00026
.00025
.00036
.00035
.00036
.00036
.00034
.00035
.00038
.00036
.00042
.00042
.00028
.00029
.00046
.00042
.00034
.00039
.00044
.00046
.00035
.00032
.00053
.0005 1
.00040
.0004 1
.00027
.00024
2nd
.00040
.00042
.00023
.00021
.00016
.00016.
.00022
.00020
.00027
.00017
.00022
.00023
. 000 17 . 000 16
.00025
.00025
.OOO 18
. 000 19
.00036
.00034
.00028
.00031
.00036
.00034
.00031
.00028
.00036
.00041
.00040
.0004 1
. O O O l B
.00017
3r d
.00026
.00027
.00025
.00026
.00018
.00019
.00023
.00023
.00028 . 000 18
.00023 ,00024
.00020
.00022
,00024 .00037
. 000 18
.OOO 18
.00036
.00034
.0002 7
.00029
.00032
. 000 30
.00028
.0002s
.00034
.00036
.00031
.00033
.00019
. 000 19
4 t h
.00025
.00025
.00021
.00023
.00014
. 0001s
.00017
.00017
.0002 1
.00016
.00024
.00024
.00017
.00022
.00017 I 000 18
.00020
.00020
.00032
.00031
.00025
.00028
.00028
.00029
.00021
. 000 19
.on032
.00038
.00034
.00035
. 000 15
. 000 14
5 t h
.00025
.00026
.00026
.00019
.00018
. 000 18
.00022
.00022
.00029 ,00020
.00022
.00023
.00019
.00019
.00022
.00025
.00017 . 000 18
.00030
.00029
.00025
.00027
.00028
.00027
.00027 -00024
. OOO??
.00036
.00031
.00032
.00021
.00020
Avg .
.00033
.00036
.00025
.00023
. 000 18
.00019
-00024 .00023
. . n m 3 u - - - - -
.0002 1
.00025
.00026
.00022
.00023
.00026
.00029
.00020
.00021
.00036 -00034
.00028 -00031
I . 00034 .00033
.00028 -
.00026
nnnqe . ""VJO
.00040
.00035
.00036
.00020
. 000 19
Avg. Periods 2, 3, 4 , 4- 5
.00029
.00030
.00024
.00022
.00017
.00017
.00021
.00021
.GOO26
.00018
.00023
.00024
.00018
.00020
.00022
.00026
.00018 ' .00019
.00034
.00032
.00026
.00029
.00031
.00030
.00027
.00024 '
.GOO34
.00038
.00034
.00035
.00018
. 000 18
.5M H2s04 2 h r s - 200°F
.81 in/mo
.20 inlmo
.31 in/mo
.22 in/mo
.20 i n l m o
.OB i d m o
.44 in/mo
.17 i d m o
.22 inlmo
.11 in/mo
.69 in/mo
.go in/mo
.62 in/mo
.% inimo
.20 in/mo
.19 in/mo
Time t o Fit S u r f a c e 6% PeC13 Meld - -
9 6 h r s
72 h r s
24 h r s
96 h r s
24 hrs
48 h r s
72 h r s
72 h r s
96 h r s
216 h r s
266 h r s
300 hrs
264 h r s
216 h r s
96 h r s
48 h r s
72 hrs
48 h r s
96 h r s
a2 hrs
5% h r s
22 h r s
96 h r s
&a h r s
a2 hrs
24 hrs
24 hrs
24 h r s
24 h r s
24 h r s
72 h r s
02 h r s
Hee t N o .
FV-70
FV-11
FY- 7 8
RV-296
RV -294
RV-297
FY-79
FV-17B
1 0
TABLE B - 6 -- CORROSION RATES I N B O I L I N G 65% HNO3
ON WELDED PLATE WHICH WAS REANNEALED
AND THEN SENSITIZED AT 1200'F
I n c h e s Per Month 1 s t
.00039
.00032
.00037
.00035
.00036
.00044
.0005 1
.00031
2 nd
.00037
.0003 1
.00033
.00031
,00030
.00036
.00045
.00027
3r d
. 00032
.00032
,00031
.00029
.00029
.00032
.00048
.00022
0- 4 t h
.00033
.00031
.00030
.00026
,00024
,00028
.00052
.00021
-- 5 t h
e 00335
.00036
,00033
.00030
.00029
.00031
.00058
.00022
-- Avg .
.00035
,00032
.00033
.00030
.00030
.00034
.0005 1
.00025
-
I
...
u u
Average Corrosion Rate mils/month
F N W 0 0 0 0 .k I I U
35 Cr-20 N i
30 Cr-25 N i
N i
1.0 s i
FV 56 310 with .03 si
0 with .28 S i
310 with ..33 Mn
with .020 C
310 with . 2 2 Cb
309 with .008 C
309 with .004 c
309 with .OOsc
309 with -026 c
..
E 0 0) H 0 Z
P +3 N 0
. . . . . .. . . . . . . .
Average Corrosion Rate m i Is /month
R I
L
. ..
13
FV 19B 310 with 1.0 S i
?V56 310 wi th - 0 3 S i
'v57 { l o wi th . 2 8 S i
V17A 110 wi th . 3 3 Mn
10 with .020 C
D44 10 wi th .22 Cb
V296 09 w i t h .008 C
19 with .008 C
0
E 0 . rn
. H 0 z
h) 0 lJl
n
--
I
P
Q
u
Average Corros ion Rate m i l s /month
F I- r r N w
P I 0 0
D I I 0
N w 5?- cn 0 0 0 0
r I Y Y 0 I
0 U 0 2 \o 0 0 0 0 0 0 E 0 0 n
r
35 Cr-20 N i ~
30 Cr-25 Ni
FV 70 30 Cr-15 N i
FV 19B 310 wi th 1.0 Si
FV56 310 wi th .03 S i
FV57 310 wi th . 28 S i
FV17A 310 with . 3 3 Mn
FV 19A 310 wi th .020 C
GD44 310 with . 2 2 Cb
RV296 309 with .008 C
RV29 7 309 wi th .008 C
FY 79 309 Cb
c)
8 0. cn w 0 z
M r c n
h, 0 VI 0
0 w
Y
9 P 0
I
Q
R 0
P
Average Corrosion Rate mila /month
I ’ 0 .b Ln m U 00 W 0 e
Y Y D D 0 d
f
0
E X OQ
+ 0
X N rn
c” + i2 z P, z 0 w 4-
r n, N
r H n
,E
. . . . . . . . . . .. -. . . . . . . . . .