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~ WATERTOWN ARSENAL ! LABORATORY c:(

MEMORANDUM REPORT NO. WAL 710/664

A Studz of 1Woocbr" fractures in Rolled Armor Pl&te

)UJ"Jlttt ' ·" (! OFl='f f '

19"

BY

I. L. REED Research Metallurg"1Co.:::~~~

tJN CLASSIFIED C i

Inte11 & s · ' ec Q

DATE 19 June 1944

'W'ATIRtOWN .USUAL WAnRTP., ••··-

84 10 23 064

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Dmdllll lUfCll! 10. W. 71QL.6.§!!: 1anial 1.-.,on oa lrobl• B-2.2

atwt,.Y o,! 'Woody' ll'aog11 1n lolled .u-g na,, ~ ~l&Of ---

~ '\ ~ -t~J .l • ar1e1 ot 3/~ l ~ mid~ ,h1~Ue4 'bf

,h, l~plio s,e.i OozporatiOAah ihowd a aarked. ,-.aa, ~o~ciq-Vtruw.re1;wre-iaftniCS'e4.~ The «iooqr'fno­\ur• US1&ll.J' bae a tine 1v1att4 appallZ'D8e and _.. oo•lioa­.U, eriuue ot ntpturl4 f1lr••• the 4,-~ocm.4lt1oa AneloS»• vh& \he traoture plane 11 parallel to the maJor rollillc 41:r .. Uon ad. 11 oauaed. 'b7 ~ pre•enoe ot tine nometalllo lnolulon• 1n the plan•• of rupture vblah h&Tt a "neppecl.1 ,vpMn1118e. Iha •n•• ot inolu•ion.1 gens~ foun4 in the ateel.a inTe• 'lca'tl eiah exhibit -ilwoo~ture1 are .U1oatea GI" OCllll'l• old• mlph14e-ailloat••• 0oaallou.11¥, iv.aka of tiwmS• aU:r14• er OOllplG WUI a •eooiated vUh airooDll11l ni\:ridel ... to111L4 111hioh also result 1A the .... ,tteo,. !he nmmotal.Uo lnalUlim• are oocaaion.ally anooiatad vi \h aetalllo bandiD&. !be 4ecr•• of -irwooq appear•oe inorM•H vi \h the qu.aati Q' ot DOJ111eWllo 1Aclua1one a• well aa the 1nequ11,7-ia-raduction in \he ,w . nlliDC d.1recUon1.t_~•fore, ,,,.i• lbowillG 'Woot,-• b'actv•• po,, ••• d1reat1onal.ropert1••·

Ike • the ...U. amber of uapl•• e:mldne4 aa4 &111 ,o U1e tnnl4•aq et the laal.li1Uc tHh appl1e4, no conolulloa• oaa lte drawn • ·t.h• relation 'bnvec \he "Wooq1 :f'racbtll:MUall L IPIIIU•tS.o pHJertie• of \he plat••· -.~ om

Ul 18 ,tM 1. this 1nTest1gat1cm •• c•dute4 a • pan o:t the~ oa \u

b'aowr, te,, a, a ••aur• of ,teal •ouncme•• now ill procre11 a,·. \:bi• ar•anal. 11Doq9 fn.otures usuaJ..q ha:re a fiae striate£ appearaaoe wi\h 'he lhal.Tbc in. IIOlla oaN1 • aiml'• •• to 'be 1n4.1atill&ll1ababla a, -.oh ¥1\h ~ naked -,.. !he 1tr1&Uon1 in theN t7Pe1 of tnom111·,1,J"e eS.\bar f&1ri, oonUnUO\l• o:t UT ahoY m4eno, of :tr~an.t.ecl fibre• wbiq , are •Wlar •• the nptve4 gn1a 1A ••WA tn•• of wood, •• 11CQ'~ 1. the •woq• aond.1tion-. b• COAf1D.t4 to the omtral portion of the ;.,1011

I '/ If 4

• • • • • • • • • • • • •

-

or may occur uniformly throughout. Per1onnel at the Ordnance Research Center h~ve expressed concern over this condition and indicated the de11rability of nscertaininr, the factor, responsible.

2. This type of fracture, which has been ob1ened in certain electric and open hearth steels when the fracture plane 11 Parallel to the major rolling direction, wa1 know to be caused by elongated or intermittent type, of nonmetallic inclusions. Preliminary studies were made on 1everal 3/4" and l ½" thick fracture teat bare submitted on 19 January 1944 by the Republic Steel Corporation. These samples showed the "woody" condition. In order to determine the metallurgical character­i1tic1 of this tyne of material more thoroughly, aamples of production ~late 12x12xJ/4" and 12x12xl½" were requested and obtained from the Republic Steel Cor~oration. One sam~le of 1 inch thick thoroughly croa1 rolled plate manufRctured by the Great Lake1 Steel Corporation was al10 investigated. The Republic Steel Corporntion later eubmi tted large V-notch Charpy impact bars tor teat in the laboratory and thia material wa• also examined as a ~art of this inveatigation. These bare were 3/4 and l" aqua.re and are referred to below along with the other sample, inTolTed. Ballistic behaviors under t he projectile-through-plate teat• are recorded on the plates involved when this information waa available.

Behavior under Approximate Pr0Jectile-Thr2u~h-Pl1t1 Te1t

!ize Exit Dia. Spec. AXS..495 Rev. 2 SamJ:!le No 1 inches Inchea Snec 1 AXS-488 Rev1 l

Re~blic Steel Corp1

1 4xltx3/4 2xJt 1ailed

6 4xl¼xJ/4 1-3/4%2¼ Acceptable

5 4xl¼xl½ JxJ-3/4 J'atled

9 4xltxl½ 2tx2-5/8 Acceptable

RH 11761 12xl~x3/4 2-J/4xJ 1a1led

RH 53715 12xl2x3/4 2¼x3 Failed

RH 11761 12xl2xl½ 2-5/8x}t Failed

RH 11792 12xl2xlt 2-J/8x,¼ Acceptable

.A.-1 lxlx6 2tx2t Acceptable

B-2 lxlx6 2¼x2-3/8 Acceptable

C-4 3/4x3/4x6 2tx2-3/8 Acceptable

D..2 3/4x3/4x6 2:,2-3/4 Acceptable

Grei1~ Lllsea Steel Cor;e.

10 J:dx6 2x2-3/4 Acceptable

-2-

• • • • • • • • • • • • • •

•

3. Metsllurgical eXMtination 0onei1ted of the following teats.

A• Chemical Anal.YHI. ~· ' ,2. 1racture Test tor Steel Soundneae. DTT :' 1 ·, I )

11 /'lrl 11 I ]

i. 1racture Teat tor libre. ur:i

i• Macroscopic Examination.

.!• !Hcro acopic Examiru:;tion • \ v ... J

!• V-noteh ONlr y I mp11.ct Teats. I.;'! ' . ' : -~ r·

I!.• Tensile TerJta.

a. Hardne11 Testa.

· 1 r ' .i. .. l

. I I ' ' ,. •r t l ' , ~ . .

I 1 . , ,._:

4. The results of the above te1t1 in detail are preaented below:

A• Chemical Ana).Yee,.

The chemical a.nal7.ee1 of the 1erie1 ot 1ample1 are given in Table I.

Thick-neu

Table I Chemical ,lpel7ae1

Sample No, Inchee .L _lli.L,. Ji ...L. _J_ ....!1.. ..£t._ .J!2 V .,.2l! :a .AL RePUblic

1

6

5 9

RH 11761

RB 53715 RH 11761

RH 11792 .A-1

:B..2

0..4 D-2

3/4 3/4 l½ li 3/4 3/4 lt l½ l

l

3/4 3/4

,26 .86 .25 .017 .0111.58

.25 1.17 .28 .023 .020 ,84

,28 1.06 .26 .021 .016 .90 ,28 1.10 .25 .026 .013 .87

.28 .94 .22 .015 .0111,88

.29 1.28 .35 .017 .014 1.02 ,28 .87 .20 .023 .0111.63

.28 1.22 .30 .011 .015 .95 • 27 1.19 .25 .025 .013 .85

.29 1.16 .27 .017 ,018 .79

.25 1.20 .28 .020 .014 ,85

.28 1.16 .30 .017 .017 .81

. 75 .26 !raoe .09 .0019 ,01

.77 ,29 !raae .07 .0015 .025

.77 .2s Traoe .10 .0016 .015

.74 .2s !r~c• .09 .0014 .015

l,00 .30 .085 .10 Trace .015

,78 ,33 Trace .10 .0025 .02 .96 · .29 .os .08 Trace .Ol

.72 .35 Trace .09 .OOJ .015

.78 .29 Trace .09 ,0014 ,02

• 76 .29 Trace .07 .0016 .02 ,77 .28 Trace .07 ,0014 ,025 .77 .26 Trace .09 .0011 ,01

Great Lake• 10 1

..!1..!t • 3() 1.02 ,81 ,021 .022 Trace .54 .23 Nil .07 Trace .013 ,06 .08

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W1 th the exoaption of the :lt!pll)U.e b•\ lo. II 11761 ad the Gr•• Lite• pl.ate lo. 10 ~ balanoe of the heat• were treated with special addition agct1 oontatnin« boron. Only • trace ot this elm.ant, nu~ o.0009~, wa, detected 1n the J/4• and. la' thiok platea rolled from heat lo. llH u761 and the Gr•t LBltee plate lo. 10.

:a,. J'ractu.re Te st a _tor Steel Soun~~•

ligures ~4 inclusive illustre.te fro..cturee of the' «>odt' type and thoae exhibiting llhelrlnl:. ~he relUlta of these t es t • are IUIIIIArised 1n Table 11.

Sample lo 1

llc>ublio 1

6

5

9

llB 11761

BB 53715

T.A:BL.111'

aimitiJ3XY of 1racture Teet, for Steel SoundneH

~ronmate Size of

lotched. Bar B.roken Slowly under Pre!!_

lul-1/lf.x3/41

1-.l,.1/ lb:l.i 1

4-zl,.1/ lul½ •

ha.cw.re B&U.y ••I.o~ Trani

j -

J -I

D D

Deacr1pt1on of Fracture

~es of Woodiness

Wood¥

1.'raoea of lfoodin.a.ns

lo woodiness in l.ol'l€ and ~Ml

fraoturea

ShelviJ16 in :LoDi and Tran.I

clirectiollil. !rracos of

Woodiness onlJ in Lone;.

frooture.

•Beu.nor under Projectile

fhroU&h Plate ,,,t J'ailecl

'l:Z.'!,-1/ 41 ex. die..

.&ooaptable l-)/ 4i.2.-l/ 4• ax. d1a..

Ja1lel 'JZ)-J/41 ez. 41&.

Acceptable 2:-1/ >ti2r5/ 11 c. d1a..

Jat.114 2:-J/4xJ• •• dla.

Jailel 2:-1/ 1-J I IX. ci.11!.

Jailecl

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" " ' . "

ml 11761 0 Woodine as 011.l,T

in loll& fl"Mtt.u-o. a-5/ h}-1/ '4• ax. die.. · · ·.

RB 11792

Qreat Laite9

10

0 I Woodiness cml7

in~. fi-e.ot~.

.looep,able :<: 2-J/ Bxa-3/ 8 • ex. di.a. ~

lo t..oodinesc in )x6xl" I I Long and ~Ml

t.raotureo. •Spec1t1cat1on .iD-4§5, limsion 2. Specification .AXJ.iiBit, levislon 1.

••J.on&1tudiDAl fracture parallel to maJor direction of rolling. trannerae fra.otw• at right an&l•• to uJor riireotion ol rollin«.

• • • • • • • • • • • • • •

- •

The tractµre '98' reveal e the direotioa&l 'Pl'Ol)erties in 11111ple1 le•• 1, 5, lUl 53715 (3/41 thick), RH ll76l (lt 1 t.hick) md IUI ll792 (lt 1 ih1oltJ whereat IMl.ele• 101. 6 end 9 were more t horou&llly cross rolled. Sall»l• 101. BH 11761. (3/41 thick) and Gl.S 10 'fff• relB.tively free troa nonmetallic 1egregaUona and 't.'ort1 tborcru&llly aroas i·olled, no "voocilne11• l»eiae mdent 1n ftither of these aamples.

lio conoluaiona could be drum on t lie r elc.i.tion between 'woodl'' t:ractura1 and spalling characteristics due to the insuffioient mmbar of 18111pl•• eDmined and also to the apparent inadeqtu:i.oy of the ball11tia teat appl1e4.

.2,e Jracture fest for libre.

' . [ .· L

' .

lracture tests for fibre ware made on semple• of the J/41 ad r lt' thi* plates whioh were reqne1ted for aet&l.11.u-[.1.oe.l s~ and. the relUlts :,. are report ad below: ·

lapg)l1 !B@ber lt¥W• &atW &':1n,U Bars1a•s1 JW 11761 - J/41 J1brou1 29J 1H 53715 - 3/4• ftbrou• 269

IR 11761 - 111 J1brou1 262

llH 11792 - 11• l'ibrou1 269

!- ICacroS09.l:iC ExaminatiOB•

1ig11ree 5-7 incluaiTe 1llu1trnte the ~·oatructUJ'e of •-plea etched 1n hot acid which had. a "woq' fracture 11114 al.10 tho•• which shoved no eTid81lce of a 1wr)ody1 fracture. These rewlt• are tummarised in Table III.

-5-

• • • • • • • • • • • • • •

.. ,-,..... I

... "' ' I

r

•

RePµbUc l

3/4"

6 3/4•

1!• 9

1~•

RH 11761 3/4·

RH 53715 3/4"

RH 11761 l½"

RH 11792 l½"

C-4 3/4·

D-2 3/4"

Projectile Thr ough Plate

T:f&ble III &crostructure

Macroatructure Test ~ .cture Longitudinal Tra,noxeroo

Evidence of cent erline •J' Wo ody Slight evidence of

t l i ti ftegre~ation more deeply cen P.r ne segrege. on etched.

F

p

., F

r

p

p

p

p

p

TrA.Cf'lG o f C t 11 ti Centerline 1egregBtion Woodines s en er ne segrega. on more deepl1 P-tched.

Woody c eni er eegre~ation

Trnces of Fairly uniform Woodiness bandine

No Wo od i ne s s Sati sfsct ory

Shelving Tr~ces of Sntisfact ory Woodiness

Woody Cen ter seere~ation

.Woody Center 1rgregation

Woodi ner,s Evident Cent er segregFi.tion

'l'rA.Ces of Woodiness Slight banding

Treces of Woodiness Satisfactory

Tracee of Wo odine s s Occn1ional banding

Center segregation more deepl y etched.

Pronounced center eegreg~tion more deenly etched.

Sat isfe.ctory

Centerline segregation more dee ly etched.

Center segregation more deeply f!tched.

Center segregation more deeply etched.

Center gegrer..ation more deeply etched.

Some center segregation more deeply etched .•

Some center segregation more deenly etched.

Fairly uniform more dee. ly etched.

Great Lakes

10 No Woodine 9 s Satisfnctory Sa, t1 s f A.Ct o ry 1•

•r.Failec'I

-6-

• • • • • • • • • • • •

• •

The samples which shoved evidence of dir~ctional properties, by Tirtue of t he fa.ct t '1a.t t hi, ae etched more dt>eply in the tra.naveree direction, nlso revealed t he nresenJe of "woodineu" in the fractures to various degrees. In other words• a :fairly go?d correlation between "woody" frf\.Ctures and the maerostructure was established. If extreme diffarenCAI in etching cha.racterist ice exist in the two directions ( indicating directional pro:oertiea), t he 11 wo dy11 t y;>e fracture may be ex ected t o be observed in the loneitudinal fracture •

.!• ~icro sco ic Examination

Typical nonmete.llic incluaions 3.lld representa tive micro­etructur es found in sam~les showing various degree, of "woody" fractures are presented in Figures 8 to 14 inclusive. The results are tabulated in Table IV.

The results of the microscopic exami~ation indicate that fine nonmetallic inclusions in the plane of rupture result in the "woody" t~pe of fracture. 1igure 1, illustrate, a "woody' fracture, broken in the lonr.itudinal direction of the l½• thick Plate No. RH 11761. Thie fracture was nickel plated in order to preserve the contour of the fracture d11ring the metallogra.phie po lishing operation e.nd eubeequentl1 cut trane­vereely and examined for the !)resenee of nonmetallic inclusions in planes of ru~ure. As noted in Figure 8, the erou section of a •woody" fracture hae a "1tepued" aP)') earance. Microscopic examination revealed the presence ot tint nonmetallic inclueions on the 11 ehelvea• of the stepped fracture, indicatin& tha t runture has occurred along these planes. These nonmetallic incluaione were identified aa silica.tea, com~lex oxid&-aulphide-ailicate1 and in one case zirconium nitride was present on a plane of rupture, ••• 1igure 8. The dietribl\tion on nonmetallic inclusions in the croaa eection of t he se materials is also shown in Jigure 8.

In the longitudinal aeetion of the 1½• thick plate No. RH 11761, and in other sampl es examined, elongated nonmetallic inclueion1 of the same ty~e. namely com nlex oxide-aulphid&-silieate• were detected, aee r1~rea 9 and 10. Occaeionall7 other types of nonmetallic incluaiona such as alumina and titanium nitride stringer, were found in sample, shoving the "woody" t yrie of fracture, see Pigurea 9 and 10.

It was observed that the degree of •woodiness" of fracture wa1 more intense vith t he increase in the amount of nonmetallic incluaiona, note the abaence of elongated noruneiallic includona in pla.te No·. RH 11761 ( 3/4• thicv.:) which did not e:x:hi bit a "woody" fracture and t he presence of the nonmetallic inclueions in plate• Nos. RH 11761 (l½" thick) and RH 11792 (1½• thick). Figure 10. Also. microscopic examination of some o:f t he broken large aize Char py bars to which reference is made in Fi~u re 13 and in Table VI, indicated that with a greater amount of "woodiness" in the fractures an i ncrease in the amount of nonmetallic i nclusions was clearly demonstrated.

-7-

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reak

s o

f T

empe

red

ma

rten

site

T

itan

ium

nit

rid

e.

Occ

aeio

nal

fin

e

stre

ak

s o

f T

em~

ered

ma

rte

nsi

te

alu

min

a 1

nclu

•io

ne.

Occ

n.si

onal

st

reak

• o

f o

rlde

su

l?}l

ide

sil

icate

• as

soc

iat

ed

Tem

pere

d m

arte

nai

te

wit

h t

it&

niu

a n

itri

de.

Ore

a\ L

aket

1

0

No

Uni

form

dis

trib

uti

on

of

fin

e

Tem

pere

d m

art

en

eit

e

1•

vo

on

ines

s o

xid

e••

•JJ-

al'a

ilecl

P

aPaa

sed

Ob

erh

off

er'

• E

teh

Ke

tal l

ie

segr

egat

ion

Pro

no

un

ced

b

and

ing

Pro

no

un

ced

b

and

ing

Pro

no

un

ced

b

an

din

g

?ren

ou

nce

d

ban

din

g

Pro

no

un

ced

b

and

ing

••A

stu

dy

on

th

e re

lati

on

of

no

nm

etal

lic

incl

uei

on

e to

t

he

path

of

rup

ture

in

•w

oody

" fr

actu

re•

1•

show

n in

J'i

gu.r

e 8

.

'

• •

In the c~qe of sam~le No. 10, which showed no evidence of a "wood," fracture, aee 1igure 4, no elongated nonmetallic i noluaione were evident. A uniform dis t ribution of •mall nonmetallic inclusion, wae scattered t hr oughout t he mat rix, eee ligure 10.

Generally •Peeking, metallic banding wns associated with the nonme\allio ·inclu1ions, see Figure 11. It was indicated that metallic banding alone aa revealed by 0berhoffer 1a etch, is not alwa71 ree ponafble for "woody" fraoturea as noted in thf'l case of sample lio. RH 11761 ( 3/4" thiek) 1n which metallic banding h nre1ent and 1e not associated with elont~ated nonmetallic inclusions, see Figure 11. Also se.tn:'1le No. 10, which contained no elongated nonmetallic inclusion~, 1howed the presence of metal lic banding but did not have a "woody" fracture, see Figure 4.

Mo st of the sampl e• investigated had a tempered martenaitic structure but in some caaea emall a.mounts of pro-eutectoid ferrite were ~resent, aee ?igure 12. In the ca1e ot the failed 1½1 ~hick plate No. 5, and the 1atiafacto17 l½" t hick plate No. RH 11792, the presence of eome upper tr&natorma~ion product, w~• evident. The amount of this constituent in each plate was lea s than 15~ and therefore wa1 not considered objection­able.

Note: A. Hurli'ch conducted the metallographio work on t he occurr ence of nonmetallic inclusion, in t he nl anes of rupture ot •woody" fractures~ eee figure 8. The balance of t he photomicrographic work was conducted by M, Yoffa.

!- V-notch Cb.aroz lmuaet Teets

The reeul ts of the V-notch Charpy lmpe,ct \eetl made on longitudinal and transverse sections of 3/4•, l", and lt" thick Platea at ~70°1 and at -4o0r are given in Table v. With the exce~tion of ~late, No,. RH 11761, 3/4• thick, and 10, l" thick, the noticeable difference between t he longitudinal and trMsverse Char!)y valuea ot the variou• plates indicate definite directional '!)ro nerties. The two plate, referred to above had fairly uniform im~act values in th~ longitudinal and tranaverse directions.

It has been obeerved tha t good quality 1½1 thick plate, tree from directional nroperties, when heat treated to the same hardne11 aa so~e of t 1e m~terial tested in t his inveatigation (250-26o Brinell hardness), hat a V-notch Char ;:>y value in t he transverse direction of ai1, roximately 80 tt./lba. aa noted in Table V. The tranaTerae Charpy values of material of t he aama hardnese level which ~osReseed directi onal properties varied from 20-46 tt./ l bs. This would indicate that t he rati o o! V-notoh Charpy Taluee of •atiafactory cro ss roll ed Plate to that of improperly cro sa rolled plate would be apnrox1mately 211.

-10-

• • • • • • • • • • • • • •

- -

The reaultl of the impact teat• described in Table V correlated vith t he fracture studies for steel quality.

'.rhere was no marked variati on in the im:1act valuea obtained on bare cut in the same direction of' rolling at -40°1 and nt +70°r. Apparently thia material was satiaf'actorily heat treated., the f'raeturea ot the impact bars in all cases being tibrou,.

Another series of V-notch Charpy teete were made on large eize Char~ bare, 3/4x3/4x6" and lxlx6" which conatituted the f'u.11 gauge of t he plates teated. Also comparative teats were made on the atandard. .394x.394" V-notch Char~y bar · and are included in the eumm~rr of r11ult1 1hown in Table VI.

Thia particul ar mat erial which ahowed only t raoe, of woodine11 ae fractured, see Fig11re 13 waa heat treated to eevera.l ha.rdne1& level• • namely from about 320 to 388 Brinell and had impact values not too inferior to crou rolled material heat treated to the same hardneH levele. The11 1teel1 a.11 exhibited fibrou1 fr11.cture1 at the eeTeral hard.nee• levele.

In general, t he Char~y value, of thie eerie• of samples showing evidence of woodiness were eomewhat lower than those determined on other type• of cross rolled armor plate at the ae.me hardn11a level••

E• Ten11le Testa

Tenaile test • made in the longitudinal and t raneverse directions on a&JD1ilee from 3/4", l" and 1½1 thick plate• are given in Table VII.

Directional ~ropertie• are evident in Platea which exhibited "woody" fractures revealed by the fracture .teat for steel 1oundne11 and other metallurPical te1t1.

Platea Noe. RH 11761, 3/41 thick and No. 10 were a:!'Parently croea rolled to a greater extent than the re• t of the series a• noted b~ the •mall difference• in the ductilit1 of the longitudinal and tran1ver1e teat a.

The reaulte of the ,!1h7dcal tests correlated cloeely- with the metallurgical tests re~orted herein.

,a. Hardness Testa

The »rinell hardness teat• were made on the cros, sections of the plate• and the value• are reported in Table• V, VI, VII. In all cases t he plate, were heat treated t o a uniform hardness along the cro na section.

5. The "woody" tn>e of fracture has been ob1erved in rna.ny electric and open hearth steels, both domestic and foreign. It is apparent that this condition re1ult1 from an improper refining and deoxidation practice at the steel source. In an 1mnronerly-..ref1ned and deoxidized heat, these

-11-

- - - • • • • • • • • • •

Table V V-notch Charuy I mnact Value, Dete rmined on

3./4" , l A" and 1i." Thick Pi -

Temp. Sample No,

Thi ck- Specimen of Foo t ne sa Direct i on .filB! Test ~_q

Republic

RH 53715

RH 53715 3/4"

RR 53715 3/4"

RH 11 761 3/4"

RB 11 761 J/41

RH 11 761 3/4• RH 11761 3/41

RH 11792 1½• RH 11792 lt1

RH 11792 1½1

RB 11792 11" RH 11761 l -!1

RH 11761 l½" RH 11761 l ½"

RR 11761 1½" OreAt Lakea

10

10

10S 10S

•7•71brou1

Long.

Trans. 269 .. 70°F 20.8

Long. 293 • 70°1 ~-5 Long. 293 -~OF 35. 8

Trana. 293 • 70°1 36.3 Trans. 293 -4o°F 33.3 Long. 269 • 70°? 9(). 5 Lon,,~. 269 -40°1 83. 0

Trans. 269 +70°F 52.6

TrAna. 269 -4o0J' 47.5

Long. 262 •700J 95.1 Long. 21~2 -40°1' 93.0

Trana. 262 ~70°F 32.9

Long.

Trana. Long. Trans.

320 • 70°r 32.g

320 47007 26.4

320 .. 70°1 35. 5 320 • 70°1 25. 3

Descr~...E.ll.Q.P. of Fracture

•F - PronoW\ced continuous laminat i ons

F - . 'renounc ed c ontinuous l a:ni nn.ti ons

F - "wood.y11 fracture, fine fr8f9l]ent ed And continuoua

. striations .

1 - "Woody" fracture, fine frnt,nent ed M d continuous striat i ons.

F - Ho "woodiness"

1 - No 1 woodi nes1•

J' - No "woodiness"

1 - No "woodiness•

J - Broken ends of striations 1 - Broken ends of 1triation1

F - "Woody" fracture, tine continuous atriationa

F - "Woody" fracture, fine continuous striation•

F - Broken ends of striations F - Broken enda of striations 1 - "Woody" fracture, fine

continuoue striations r - 1 Wood7" fracture, fine

continuoue striation•

"I - No 1 wood1ner. s 11

1 - ?lo 1 wood1neas" F - No "woodines s" r - No "woodiness"

Not e : With t he exce11tion of sam le lOS, V-notch was cut in bars pe rpendicule.r t o 1urface of :1l e.te.

On sample lOS, V .. notch wna cut ~1Etrallel to su.rfe.ce of plate.

-12-

• T

able

VI

• Y

-not

ch C

har:E

J: Im

pact

Vfa

.!ut•

Det

irm

ined

on

3[4•

en

d l

" T

hick

Pla

te H

eat

T:-e

ated

1:t

Sev

eral

H~r

dnes

_e

Lev

eie

• :r

oot

Poun

da t

7P°F

J/

4• a

nd

1*

Sta

nd

ard

S&

mpl

e T

hic

k-

Tnic

k

.394

x.39

4"

• N

o 1 n

ess

Dir

ecti

on

BH

N Ch

arr:z

B

~a

J'

ractu

re

Cha

rpz

Bar

J'

mct

ur1

.&

.-1

1•

Tra

ns.

33

1 20

2 •J

' -

hid

en

ce o

f w

ood

ines

s 25

.3

•J'

-T

race

fin

e w

ood

ine

s•

• .A

,.2

1•

Tra

ne.

34

1 15

8 Y

-E

vid

ence

of

woo

din

ess

21

.3

l -

Tra

ce f

ine

woo

dine

ss

J-3

l"

T

ran

•• 36

3 14

6 1

-50

i w

oo

dy

18.1

J'

-T

race

fin

e v

ood

ines

s

• J-

4

l"

'rra

ns.

37

5 1

23

"I

-T

race

woo

dy

16.9

F

-T

race

fin

e w

ood

ines

s

Ll

1•

'l'r

ane.

34

1 15

8 J'

-T

race

woo

dy

19.4

F

-fr

ace

fin

e v

oo

din

ese

• B

-2

l"

Tra

ns.

36

3 14

0 F

-T

race

voo

d.7

17.3

Y

-'!

'rac

e fi

ne v

ood

ines

• B

-~

1"

'fr~

.ns.

37

5 13

4 F

-T

race

woo

dy

13.6

Y

-T

race

fin

e w

oodi

ness

•

.., I

L4

1

• T

ran

s.

3gg

123

r -

Tra

ce v

ood

.7

15.5

F

-T

race

fin

e v

ood

1n@

ee

I-'

'f

• C

..l

3/4·

'l'

ran

•• 32

1 10

0 F

-'!

'rac

e vo

ocy

2

5.5

1

-T

rRC@

fi

ne w

ood

ines

s C

-2

3/411

T

rsn

a.

341

79

1'

-T

race

woo

dy

us.3

J'

-

Tra

ce f

ine v

oo

din

ee•

• C

-3

3/4

* '1

'ren1

1.

352

79

r -

Tra

oe w

oody

16

.4

1 -

Tra

ce f

ine

woo

din

es1

C-4

3/

4·

T!'s

.ne.

37

5 79

•

-T

r2.c

e vo

ody

16.5

F

-T

race

fin

e w

ood

ine

ss

• D

-1

3/'i+

" T

r~:is

. 34

1 79

J'

-

'!'ra

ce w

oody

1

8.l

F

-T

race

fin

e v

oodi

nes•

D

-2

3/4·

T

ran

s.

363

60

Y -

-Tra

ce w

oody

1

2.4

7

-T

race

fin

e w

ood

ines

s

• n.

.3

3/4·

'?

ran

s.

375

bO

1' -

Tra

ce v

o0d

y 1

3.s

7

-T

race

fin

e w

ood

ines

s D

-4

3/4

" 'l

're.

ne.

3gg

60

7 -

Tra

ce v

oo

q

12

.11

~ -

Tra

ce f

ine w

oodin

es•

• •F

=7

ibro

us

frac

~~

re

Bo

te:

T-n

otch

mil

led

?ar

all

el

to

surf

ace

of

!Jle

te

and

Para

llel

to d

irecti

on

of

roll

ing

.

• D

epth

of

no

tch

on

3;4•

th

ick

1la

te -

1,s

•.

Dep

th o

f n

otc

h o

n l*

th

ick

pla

te -

1/4

•

•

.. • • • • • • • I I-

' F

• • • • • • • •

Ta

ble

TII

Ree

ul.

ts

of

Ten

sile

Tes

ta M

ade

on 3

/4•,

111

an

d 1

!•

Th

ick

Pla

te

Sam

ple

No

RH 53

n5

RH 5

3715

RH

11

761

BB

11

761

BB

11

792

RB

11

792

RH

11

761

RH

11

761

10

1

0

T.s

. T

hic

k-

.1i

Set

n

ess

Dir

ecti

on

Lb

1/S

o,

In.

3/4·

3/

4·

3/4·

3/

4"

l½"

l½"

1½•

1..!..•

2 1

• l"

Lon

g.

119,

700

Tra

ns.

11

9,70

0

Lon

g.

134

,100

T

ran

s.

133,

500

Lon

g.

11

6,3

00

T

ran

a.

116,

900

Lon

e.

11

8,0

00

T

ran

s.

117,

900

Lon

g.

156,

250

Tra

ne.

15

2,5

00

T. s

. L

b,/

Sg

, In

.

136,

000

136,

000

14

6,0

00

14

6,oo

o

134,

800

135,

300

129,

250

129,

250

170,

000

169,

000

~ ~

Rem

arks

JP

.], RA

:B

HH

•Fra

ctu

re D

e1cr

ipti

on

s -

19.7

b0

.8

Sh

elv

ing

in L

ong

. an

d T

r-an

s.

15

.0

42.4

26

9 d

irecti

ons.

T

race

s of

w

oo

din

ess

on

ly i

n L

ong

. d

irecti

on

s.

lb.8

56

.7

No

evid

ence

of

wo

ody

frac

ture

in

16.s

54

.8

293

Lon

g.

and

Tra

na.

d

irecti

on

s.

No

dir

ecti

on

al

pro

pert

ies.

19.7

b4

.9

269

Woo

dy f

ractu

re o

nly

in

Lon

g.

17.9

55

.6

dir

ecti

on

. D

irecti

on

al

nro

pert

1es.

20

.7

65.5

26

2 W

oody

fra

ctu

re

on

ly i

n L

ong.

16

.8

49.s

d

irecti

on

. D

irecti

on

al

pro

pert

ies.

14.3

50

.6

No

evid

ence

of

woo

dy fr

actu

re

in

320

Lon

g.

and

Tra

ns.

dir

ecti

on

s.

14.3

47

.0

Dir

ecti

on

al

Pro

pert

ies n

ot

mar

ked

•

•7ra

ctu

re

desc

ri~

tion

s are

th

~se

re

cord

ed 1

n t

he 7

ractu

re T

est

for

Ste

el

Sou

ndne

ss •

1'r ,

': ,',

,'• /

• :• .•

• :•-:

t , .

. •·,

~

. ',

-.

'•

••

. . _.

-· .•

,

.. ~ .. · .

. ·.·:,·.-.

-:.·r

1··.,-·

.:·-:·

•:·-:·

•:·• ·_

·-

·· ,-

-,,-

,-,-

• I.

,,

....

•

• •

••

•

i :

r •

J I.

' .

I

-\

,-.-:-

.--.

:;;-

,:•

r.

·":'.,

....

l :

.J.

'•

.a,

·.·.:\:··,:

··.:-.:-~:-

~,J .· .

.--,~

r-:~.

r_ w

. • ••

• •

·..-

••

'.-

·.-•

.. 11

!•'2

.:

',-·

• •

nonmetallic inclullions are 11resent in t he metal during teeming and aub­aequently segregate duri ng t he solidification of the ingot and are elonGat ed in t he maJ or direction of hot r olling. It has been demonatrated that "wood:;" !ra.ot,.ire1 a.re formed when t he fracture :::ilane 1a !'arallel to t hP. maj or di rect ion of . rolling 81ld t hat t he Path of rupture nroceeda in a 11 ete:!:med" f a shion e.lon1,; T)l ane a of werurneae caused by embedded nonmetallic inclusions, chiefly of the Ailicate type.

A "woody" c onditi on in rolled a~or 1a indicative of poor metalluri~cnl ~ro ~erties and, t herefore, is not de1irable in good quality steel, the :nroduct ion of which h es oential to meet the new ballistic requirementR for r olled homogeneous armor. The •wood," fracture oondltlon, being as sociated vi t h considerable directional chara.cteriatic1 1.n the oteel, may be expect ed to i nfluence shock failures because of e~eessive directional cracking. It in probable that •woodine• s• to var,tng degree, will always be observed in the lon~itu.dinal fracture of a fully ~eat treated steel (breakin~ in a fibrous manner) which is 1traight-aw&7 or essentially straight-away rolled. The •woody" fracture C&n apparently be avoided by equality in 1)ercentage reduction in the two direction,. The l&rP.er and more numerous the inclusion• become the greater la the degree of •woodiness" developed in a 1teel with directional characteri1tic1 when fractured longi tud.inally.

.A'RPROVED:

/!1~ Major, Ordnance Dept. Chief, Armor Section

• • • -1!>-

• • •

e.,t.~ J:. L. RllD Reeearch Metallurgist

• • • • • • •

.... ·,. . ..,

,·. ·l

·,

... -: .,.,· .,,_~:•t. l.

WATERTOWN ARSENAL

I;'" THICK ROLLED ARMOR EXHIBITING WOODY F"RACTURE I MAY 1944 MAG. X 2 WTN.710-2307

f"IGURE I

~-·.- > ·<.i .. • .1

. - . :--:_.:

SAMF>LE ff, F"AI LEO

SAMPLE • 5 F'AILEO

•

1 QfDIYAl)CE ~ V.Sir""t,

WAnrA'71:>WN ~L.•

SAMF>LE '#f, 6 ' SAT I SF"ACTORY •• 1

SAMPLE f' 9 SATISF'ACTORY

'J F'RACTURES or SAMPLES Or ROLLED F>LATE SUBMITTED BY REPUBLIC STEEL CbRP. 24 JAN 1944 WTN.710-2267

3SN3dX 3 1N3V\1Nij 3/\09 J. 'It a .3 ::JnOQijd.3 1::l

F' I GURE ,~

.·.

•

•

•

3/ 4 11 PLI\TE RH 5 371 5 PTP T ES T c. l/ 4 1' X 3 11 EX I T D I A.

I 1/2,11 PLATE RH 11792 PTP TE S T 2 3/8 11 X 2 3/8 11 EXIT DIA ,

3/411 PL/TE RH 1176 1 PTP TEST 2 3 4 11 X 311 EX IT D I A,

I 1/211 PLATE RH 11761 PTP TEST 2 5/811 >< 3 1/411 EXIT DIA,

WATERT OWN ARSENAL

FRA CTURE S OF ARMOR PLAT E ~U OM ITT ED BY Rf PUDL IC STEEL CORP, ',•« ,w " : -. -, ~ :- •: ~ .-,: ::.::-:: ; :-~. ~. _ ••.• "- : ' ~- .. . " . -.' 4•1 lo TN, 7:i t- 2 286

3SN3rJX.::i .iN3 VIINH 3/\0Sl Ht <J:Uli U Ul:Jd 3cl F I GUR E 3

.... . . . .. . . ..... · .. .. - . . · .... ·-. .. .. ... ~ .... ~ .I. .... .. •

. . . 'I - . .. ... .. .. .__" . ....... , .J • • ... ' . 4 ..... . .... .. • ... • • '\ ' ..; - . , ... • ri.' ,. - : \ .

. . .. ,· - .. - ... -

t{ ......

I­ ~

C

u.

u C

C

a:

0..

u.,

a:

-4-:

-;

""""~-

---="

--~-

'='

,..;

0 ~

::c

r:::

,&,.

~,._

__

.. _

LOH

QIT

UD

INA

L TR

ANSV

ERSE

•

FRA

CTU

RES

FO

R ST

EE

l. SO

UN

DN

ESS

•a

• R

ATI

NQ

.. __ _

·--.::_·-

:.:~---~

: -·-:

-~;

-..;

... ~:

•:-'

FRA

CTU

RES

FO

R ST

EE

L

SOU

ND

NES

S AN

D

C

MN

SI

.30

I .

02

.B

l

,f,

MA

V

IC

.a.A

MA

CRO

STRU

CTU

RE

..,,s,-.

,_

WAT

ERTO

WN

ARSE

NAL

MA

CRO

STRU

CTU

RE or

3/4

" TH

ICK

AR

MOR

PL

ATE

N

O.

10

CO

NTA

ININ

G:

s .0

21

r,,,~

p .0

22

CR

.5

4

MO

.23

•..r"T"

"''

ZR

.OB

" ,:-

:,_,-

. ' ·.'

·'j I

,.,,1.,.

LONQITUOINAL TRANSVERSE

SAMPLE fl, I SAMPLE NO I

•

SAMPLE 'I' 6 SAMPLE f, 6

SAMPLE fl, 5 SAMPLE ;t, 5

SAMPLE f' g SAMPLE if, 9

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Se.m )_1le No. HR 11761 - 1)11 thick. Typical contour of 11 woody11 fracture. Step-nod appea rance. Sulphide-oilice.t e inclu sions in steel base. Failed P.rP t ee t. M~~- ;x..1 00

Sample No. RH 117(,1 - 1-\" t ':1ick . Sul nh icl. e­ailicate lncluoion on stepp0d ~,1nne of rupture of 11 woody11 fracture.

Sar.r9 l13 lTo. im 1171;1 - 1}11 t hi c k. Serie n ,' of fine nonu0t nllic inclusi ons on Jte ne~· rupt,ure. Frnt~ent of zirconitun nHrid ~ ) (yell0w u.ncl8r white lip:ht ) a.t ._ ip of middle st e p. oe e a~ro w. Gray i nclueio ne a re oxlde-silic at 9 inclusions.

Som:rlfl No • . H 11r)1 - 1-,1.," t. •ii. c;J.:: . Bro ko·1 •,d.l tcnte i neln~d on or.. rt e :J,_,ed plnno 0 f r w 1tur p of " H0 1)<1.y11 frac turo.

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1zplcal ~OMfltalllc Inclusions in J/1~" and l-!-11 '!'hick 1raoture 'l'eat Bars

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\ ---Sample No. 1 - J/4" thick. Fine oxide­~ulphlde-eilie~t• tnolu1ton1 well distributed. "1iood711 fracture - Failed P.l'P teat.

-·- ... . . . . .. --.•.. .... •· 4 •

S T lM ' &m "?le l10. 5 - l t" thick. Typical alumina inclur.ion streak in center o:t' !)late. Silicntes were aleo , re~e,1t. "Woody' fracture - Failed PTP test.

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Sample No. 6 - J/411 thtek. ~cattered tlnr. orlde-sulphide-eilicate inclusions . Trnce1 of 11 woodine~G 11 in fracture -Passed PTP t~st.

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Sarn~le No. 9 - 1~• thick. Sc~ttered fine ox1de-aul nhid.e-.111ce.te i nclusions. Trn.ces of "woo,Une£is1 in frncture -Pnes ed FTP t '"'n t.

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Sample No. llH 53715 • 3/4• thick. line ·onde BUlphide silicate inolu11one well diatr1'buted. Some "voodine$&11 and pronounced shelving in trncture. Jailed PTP tP-et.

-Sample Ho. RI 11761 - 1¼• thick. 11ne oxide sulphide silicate . inclueione vell 411tribnted. "Woody" Fracture. 1a1led PTP teat.

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Sample No. B-2. W • V-notch Char-py bar. An occa• ional 1trenk of titnniu~ nitride inclu• 1on1. TrA.ocs r1f "wood:," fre..oture •

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Sample No. BH 11761 - 3/4" thick. 1'ew ocatter ecl oxide of alumina inclusions. No evidence of "voody11

fracture. Failed P.rP test.

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Sample No. BH 11792 - l½" thick, Fine oxide aulph1de ailicate inclusions well dt •~ributed. "Woody" fracture. ··,iased Pl'P test.

Sample No. 10. of fine o:dn es. fracture.

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Metallic Ba.ndinP; Associated W:1. t h Nc•nme t,all ics in 3/1+ 11 .g.ncl l ?.·11 'I' h ick Plate

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Samnle No. RH 53715 - 3/l~" thick. Pr orl-::-'l-tnc ed bandin p: a \;no c1.nted wit '.1 occa.sbnal aul phirle ail i c o. t e includ. ons. Some "woodinei:rn " and marked she lvi ~,f:' in fractur e . Fn.ilP.d PrP test •

S,.;n!)l c No. RR 11761 - 3/lt11 th ick~ Pronounced ba,ucUn;': l:',soociated wi'\ h a f e• . .; small :i.ncl1rni rmc; . Ho eviclence of "woo dy 11

fr n.ct,ire, Fn :tl od Pl'P t e st.

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···---------~-Sample No. 5 - 1 \- 11 thick. Prononnc e rl bandin r-; a s s ociat ed with f ine oxif e- iml r·h i rl e -· s ilicate i nclus i ne. 11 Wcody ~ fracture . Fail ed PTP t ,1s t.

..

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S0_rn )Jlo Ho . RJ-I 117\ 2 - l ?/' t hick. Pr:mo11nc P- d ·band i n r,; ar,s0ciat P.d ,,;i t h ~1111 ~,ri_ i..d.•~ -o:dde- fl i l icA.te inclu o 1.ons . 11 W0:1clv 11 f ractu r 0. . f u w ;ed FTP t r->nt . . ~

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M1erostrnctt1re of 3/411 and H-" Th ick 1rp.cture T12.a t n.~rt1

Sam:)h X,:,. l 3/t~n thick. FP.rr lte , tempered nartens1te, banded ~truoture. "Wocdy11 fract11re - Failed PTP ter;t.

Sa.m r>le i{o. RH 11792 - 1~11 thick. F"rri te, u :r> ner tem-,e rat ,1re trnnsfor :1!Ltion ·:r 1J1lu cte and t19m·1Jo:-ed Marten sit,-,. 1Wo ody11 fracture .. Passed Pl'P t P-n t.

Samples Etched in :'·icral.

;.iR..r.rr, l a No. RH ll t 1l - lfr• t h1clt. '- "lm 'ie red r.1r .rt enolte a nd trace of upper tem .1erat ire trr,:n3for:1 P.. t1 on ;Jroducte. "Wo ody" fracture - Fa iled Pl'P test.

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F'RACTUlll:8 or I 11 -ND J/4" SQUARE V-NOTC•I CHARPV BARS MACH I NED FROM

REPUBLIC STEEL co•. ARMOR HEAT TREATED YO SEVERAL HARDNESS L[VELS 24 IIIIA~CH 1944 MAQ. XI WTN.710-2292

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