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ISO/TR 15608 ISO/TR 15608 Material Group 10.2 – Super Duplex Steels

ISO/TR 15608 Material Group 10.2 :
Austenitic ferritic stainless steels (Super Duplex) with Cr > 24,0 % and Ni > 4 %

Super Duplex Steels ISO/TR 15608 Material Group 10.2

The super duplex grades are used widely across all industry sectors. The primary factors that drive the use of duplex stainless steels are their improved stress corrosion cracking resistance and the potential to reduce cross sections in high-stress or high-pressure applications and tank construction. As with the other stainless steel families, the duplex grades have a range of corrosion resistance and can be divided into subgroups, depending on alloying content.

The super duplex grades typically contain 24-26% chromium, 6-8% nickel, 3-5% molybdenum, and 0.24-0.27% nitrogen.  Grades in this category are used widely across all industry sectors and 2507 (S32550) has become by far the most widely used duplex grade. The 2507 grade has a yield strength that is more than twice that of Type 316 and a pitting and crevice corrosion resistance that is similar to Type 904L austenitic stainless steel.

An empirical relationship called the Pitting Resistance Equivalent Number (PREN) has been developed to relate a stainless steels composition to its relative pitting resistance in chloride solutions.

For comparison: Austenitic steels (PREN = 24-25); Lean Duplex steels (PREN=21-32), Standard Duplex steels (PREN =32-40); Super Duplex (PREN = 40-48); Hyper Duplex steels (PREN >48).
Note: There is no exact definition for this classification.

Applications for standard duplex grades include tanks, piping, process vessels and structural applications.

Weldability of Super Duplex Steels ISO/TR 15608 Material Group 10.2

Duplex stainless steels have a very good cracking resistance due the high ferrite content, hot cracking is rarely a consideration when welding these steels. Therefore the problem of most concern in duplex steels are associated with the heat effect zone (HAZ) of welds. The HAZ problems can be loss of corrosion resistance , toughness, or post-weld cracking. To avoid these problems, the welding procedure should focus an minimising total time at temperature in the “red hot” range rather than managing the heat input for any one pass.

Preheating: As general guideline, the max. interpass temperature is limited to 100°C.
PWHT: Is not needed for Duplex stainless steels
Any post weld heat treatment should include full solution annealing followed by water quenching.

Typical material in group

Name/Grade/TypeNumberStandardProductAISIRemarks
X2CrNiMoN25-7-4
X2CrNiMoN25-7-4
X2CrNiMoN25-7-4
X2CrNiMoN25-7-4
X2CrNiMoN25-7-4
X2CrNiMoN25-7-4
S32750
F53
S32750
S32750
2507
S32750
1.4410
1.4410
1.4410
1.4410
1.4410
1.4410
S32750
S32750
S32750
S32750
S32750
S32750
S32750
EN 10028-7
EN 10272
EN 10216-5
EN 10217-7
EN 10222-5
EN 10253-4
ASTM A-240
ASTM A-182
ASTM A-789
ASTM A-790
ASTM A-928
ASTM A-479
ASTM A-815
Plate
Bar
Smls. tube
Welded tube
Forging
Fitting
Plate
Forging
Smls & welded tube
Smls & welded pipe
Welded pipe
Bar
Fitting
EN 13445-2 & EN 13480-2 & EN ISO 21009-1
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
ASME BPVC
ASME BPVC
ASME BPVC
ASME BPVC
ASME BPVC
ASME BPVC
ASME BPVC
GX2CrNiMoN25-7-31.4417EN 10213Steel cast., pressure purposesEN 13445-2
F54
S39274
S39274
S39274
S39274
S39274
ASTM A-182
ASTM A-789
ASTM A-790
Forging
Smls & welded tube
Smls & welded pipe
ASME BPVC
ASME BPVC
ASME BPVC
2A
2A
J93345
J93345
ASTM A-890
ASTM A-995
Casting
Casting – pressurised parts
ASME BPVC
ASME BPVC
3A
3A
J93371
J93371
ASTM A-890
ASTM A-995
Casting
Casting – pressurised parts
ASME BPVC
ASME BPVC
GX2CrNiMoN26-7-4
5A
5A
1.4469
J93404
J93404
EN 10213
ASTM A-890
ASTM A-995
Steel cast., pressure purposes
Casting
Casting – pressurised parts

CE3MN
CE3MN
EN 13445-2
ASME BPVC
ASME BPVC
X2CrNiMoCuWN25-7-4
X2CrNiMoCuWN25-7-4
X2CrNiMoCuWN25-7-4
X2CrNiMoCuWN25-7-4
X2CrNiMoCuWN25-7-4
S32760
F55
S32760
S32760

1.4501
1.4501
1.4501
1.4501
1.4501
S32760
S32760
S32760
S32760
S32760
S32760
EN 10028-7
EN 10272
EN 10216-5
EN 10217-7
EN 10253-4
ASTM A-240
ASTM A-182
ASTM A-789
ASTM A-790
ASTM A-928
ASTM A-815
Plate
Bar
Smls. tube
Welded tube
Fitting
Plate
Forging
Smls & welded tube
Smls & welded pipe
Welded pipe
Fitting
EN 13445-2 & EN 13480-2 & EN ISO 21009-1
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
ASME BPVC
ASME BPVC
ASME BPVC
ASME BPVC
ASME BPVC
ASME BPVC
X2CrNiMoCuN25-6-3
X2CrNiMoCuN25-6-3
X2CrNiMoCuN25-6-3
X2CrNiMoCuN25-6-3
255
F61
S32550
S32550
1.4507
1.4507
1.4507
1.4507
S32550
S32550
S32550
S32550
EN 10028-7
EN 10272
EN 10216-5
EN 10253-4
ASTM A-240
ASTM A-182
ASTM A-789
ASTM A-790
Plate
Bar
Smls. tube
Fitting
Plate
Forging
Smls & welded tube
Smls & welded pipe
EN 13445-2 & EN 13480-2 & EN ISO 21009-1
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
EN 13445-2 & EN 13480-2
ASME BPVC
ASME BPVC
ASME BPVC
ASME BPVC
GX2CrNiMoCuN25-6-3-3
CD4MCuN
1B
1B
1.4517
1.4517
J93372
J93372
EN 10213
EN 10283
ASTM A-890
ASTM A-995
Steel cast., pressure purposes
Steel casting
Casting
Casting – pressurised parts


CD4MCuN
CD4MCuN
EN 13445-2 & EN 13480-2

ASME BPVC
ASME BPVC
1CJ93373ASTM A-890CastingASME BPVC
GX3CrNiMoCuN24-6-51.4573EN 10213Steel cast., pressure purposes
GX3CrNiMoCuN24-6-2-31.4593EN 10213Steel cast., pressure purposes
7A
7A
J93379
J93379
ASTM A-890
ASTM A-995
Casting
Casting – pressurised parts
ASME BPVC
ASME BPVC
CD3MWCuN
6A
6A
J93380
J93380
J93380
ASTM A-351
ASTM A-890
ASTM A-995
Casting
Casting
Casting – pressurised parts
ASME BPVC
ASME BPVC
ASME BPVC
Table: Typical materials

Lean Duplex steel: ISO/TR 15608 Group 10.3
Standard Duplex steel: ISO/TR 15608 Group 10.1

Suitable Standard-Duplex and Super-Duplex steels for Pressure Equipments