Page 4 - SD 2507

As usual pitting corrosion resistance properties is increased when testing thinner
plates.

mV/SCE Repassivation potential (1 mA/cm²)
1000 NaCl 30 g/l mV/SCE
1000
800 800

600 SD 2507 600 UR B6
UNS N08904
400
400 UR 35N CLI-SAF2507
UR B6 UR 47N 200 UNS S32750
200 904L 0
316 UR 45N
UNS S31803
-200
20 40 60 80 100 20 40 60 80 100 Temperature (°C)
Temperature (°C)

Pitting potential taken from polarization curves Repassivation potential in 15% NaCl solution
for different stainless steels CO 2 saturated

°C °F °C °F
80 DUPLEX SUPER AUSTENITICS 175 80 DUPLEX SUPER AUSTENITIC 175
70 160 70 Guaranteed 160
Guaranteed Ask us
60 Ask us 140 60 140
50 120 50 120
40 105 40 105
30 85 30 85
20 70 20 70
10 50 10 50
UR35N UR45N UR B6 URB26 316L UR35N UR45N UR B6 URB26
SD 2507
S32304 S31803 S32750 904L 08926 S32304 S31803 SD 2507 904L 08926
S32750
ASTM G48 A - PITTING ASTM G48B/G78 - CREVICE

CPT, °C (°F ), 600 mV SCE CPT, °C(°F), 600 mV SCE
100(210)
100 (210) SD 2507
90(195)
90 (195)
SD 2507 UNS 31254
80(175)
80 (175)

70(160)
70 (160) URANUS B28
60(140)
60 (140)
SD 2205 URANUS 45N
50(120)
50 (120)

40(105)
3 6 9 12 15 %cl - 40 (105) pH
5 10 15 20 25% NaCl 5 4 3 2 1

Critical pitting temperatures (CPT) at varying Critical pitting temperatures (CPT) in 3%NaCl with
concentration of sodium chloride, from 3 to 25% varying pH
Stress corrosion cracking resistance
The stress corrosion resistance (S.C.C.) properties of SD 2507 grade are in
excellent in high temperature chloride containing solutions as well as in sour gas
applications.
°C °F Chloride (mg/l)
300 570 1000000
Super duplex MR 01-75 limits
No cracking for 22 Cr and 25 Cr duplex

200 390 100000
UR 45N CRACKING CRACKING
UR 35N SD 2506
S 31803 UR 47N +
UR 45N
NO
100 210 10000 CRACKING
AISI 304/316 NO CRACKING

0 32 Cl (%)
-
0.001 0.1 10 1000
0.01 0.1 1 10 100
Constant-strain tests in autoclave Hydrogen Sulphide (psi)
Above the curve, SCC occurs. Suggested limits for Duplex
Open circles means no SCC for UNS 32550/UR 52N + and Super duplex stainless steels