COMPOSITION OF STAINLESS STEELS TESTED

Chemical Analysis (% weight) PRENWCr Ni Mo Cu W N (1)

0,05 25

0,17 34

0,25 410,28 41

0,20 43

0,5 0,48 56

0,07 38

17,2

22

2524,9

19,9

24,5

26,7

24,5

2,6

3,2

3,63,8

6,0

7,3

3,4

4,7

1,50,7

0,4

0,9

1,5 0,40 54

316L

31803

3252032750

31254

32654

08028

08932

08926

TradeName

UR52N+SAF2507

254SMO

654SMO

SAN 28

URB66

URB26 20

12,6

5,5

6,36,9

17,8

21,8

30,3

22

24,7 6,3 0,8 0,19 43

UNS

SAF2205

AISI

PRENW : Cr + 3.3 Mo +1.6 W + 16 N

2

PITTING CORROSION RESISTANCE NaCl 30 g/l - ASTM G61

URB66

316L

N08926

20 30 40 50 60 70 80 90 100

200

400

600

800

1000

0

Temperature, °C

Pitti

ng P

oten

tial,

mV/

SCE N06 622

304L

UR45N

S 31726

32 520904L

LONG TERM IMMERSION TESTINGin

NATURAL SEA WATER(Crevice Corrosion)

REST POTENTIAL OF MCW SAMPLES in MEDITERRANEAN SEA

100 2000-

Crevice Corrosion

32550, 08926, URB66 :No Crevice Cor

08904

- 400

0

+400R

est P

oten

tial,

mV/

Ag-

AgC

l

31803

31603

30403

Time, Days

MCW : multi crevice washers

EFFECT OF CLIMATIC CONDITIONSPRENW > 40 :UR52N+, URB26, URB66 (MCW samples):

no Crevice Corrosion+400

0

-400100 2000

Res

t Pot

entia

l, m

V/A

g-A

gCl

Time, days

Mediterranean Sea, FNorth Sea, N

Atlantic Sea, F

316LCrevice

PREN > 40no corrosion

CREVICE CORROSION in NATURAL SEA WATER

SteelG C B K T

Italy France France Sweden Norway

316L 5/5 5/5 0/4 0/4 4/4

31803 ++ + + 0/5 +

32520 + + 0/5 0/5 +

32750 0/4 + 0/5 + +

31254 + + 0/5 0/5 0/5

32654 + 0/5 0/5 + 0/4

08028 + + + 0/5 +

08926 0/5 0/5 0/5 + 0/5

+/++ one/several depassivated area, no weight loss5/5 crevice corrosion on 5 coupons out of 5

Winter + Summer immersion tests , 3000 hours each

MATERIAL SELECTION FOR SEAWATER SERVICE

Free Cl2 (ppm) 0 0.5 1 0 0.5 1 0 0.5 1 0 0.5 1

10

20T(°C)

30

40

TITANIUM

UR B66 S31266

UR B66 - S31266

URB26/08926UR 52N+/S32 520

Stagnant Flange with Washer (1)> 1 m/s Threaded Joint (2)

No fitting nor Crevice geometry Crevice Geometry

If some fretting or wear is involved, the material selectionhas to be adapted (please, contact corrosion specialists)

UR B26/N08926or

UR 52N+/S32520

UR

45N

- S

3180

3

S

32

205

316Lor

UR 45NUR B26/N08926

orUR 52N+/S32 520

Water velocity

(1) (2)