Creep Resistant steels
ISO/TR 15608 Group 5.2: Cr-Mo steels (free of vanadium) with
C ≤ 0,35 %, 1,5 % ≤ Cr < 3,5 % and 0,7 < Mo ≤ 1,2 %;
Features creep resistant steels ISO/TR 15608 Material Group 5.2
This Material group are creep and heat resistant special structural (2.25Cr–1Mo) steels with ferrite–martensite microstructure. Creep resistance steels (well-known as CrMo steels), contain strong carbide and/or nitride forming elements. These are intended to provide a fine dispersion of precipitates that both increase the tensile strength and prevents the formation of the voids. Also, this increase the hardenability (the ability to form martensite). These facts obligate the CrMo steels to have restricted controls at the welding process, therefore, are susceptible to Cold Cracking and Reheat Cracking. Hydrogen during working processes (welding consumable, surface and atmospheric) induced Cold Cracking.
It is mainly used in boiler and apparatus construction for boiler drums and pressure vessels. The materials are suitable for temperatures up to 550°C (590°C).
Applications for 2.25Cr–1Mo steels
It is mainly used in boiler and apparatus construction for boiler drums and pressure vessels. The materials are suitable for temperatures up to 550°C (590°C).
Cr-Mo steel with an alloy content of 2.25%Cr and 1% Mo is however resilient to such aggressive conditions for an exposure above about 200 °C as are common in hydrogen processes such as petroleum distilling and catalytic reforming which the original rupture strength does not deteriorate.
Weldability of creep resistant steels ISO/TR 15608 Material Group 5.2
The chromium-molybdenum alloyed heat-resistant steels are generally welded with a preheating suitable for the steel grade and wall thickness in question e.g. min. 150 – 200 °C and max. interpass 300 °C. After welding, these steels generally have to be PWHT e.g. 680 – 720°C /2h.
Typical materials in group 5.2
| Name | Number | Standard | Product | Remark |
|---|---|---|---|---|
| 30CrNiMo8 | 1.6580 | EN 10269 | Fasteners | EN 13445-2 & EN 13480-2 |
| 34CrNiMo6 | 1.6582 | EN 10269 | Fasteners | EN 13445-2 & EN 13480-2 |
| 12CrMo9-10 | 1.7375 | EN 10028-2 | Plate | EN 13445-2 & EN 13480-2 |
| 11CrMo9-10 11CrMo9-10 11CrMo9-10 | 1.7383 1.7383 1.7383 | EN 10216-2 EN 10273 EN 10222-2 | Seamless tube Bar Forging | EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 |
| G17CrMo9-10 | 1.7379 | EN 10213 | Casting | EN 13445-2 & EN 13480-2 |
| 22, Cl. 3 22, Cl. 4 22, Cl. 5 B22 | K21390 K21390 K21390 K21390 | ASTM A-541 ASTM A-541 ASTM A-541 ASTM A-739 | Forging Forging Forging Bar | ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| 10CrMo9-10 10CrMo9-10 10CrMo9-10 10CrMo9-10 F22, Cl. 1 F22, Cl. 3 T22 T22 WP22, Cl. 1 WP22, Cl. 3 T22 P22 F22, Cl. 1 F22, Cl. 3 FP22 22, Cl. 1 22, Cl. 2 22, Cl. 3 A, Cl. 1 A, Cl. 2 A, Cl. 3 A, Cl. 4 A, Cl. 4a B, Cl. 1 B, Cl. 2 B, Cl. 3 B, Cl. 4 B, Cl. 4a 2.25CR, Cl. 1 | 1.7380 1.7380 1.7380 1.7380 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 K21590 | EN 10028-2 EN 10216-2 EN 10253-2 EN 10273 ASTM A-182 ASTM A-182 ASTM A-199 ASTM A-213 ASTM A-234 ASTM A-234 ASTM A-250 ASTM A-335 ASTM A-336 ASTM A-336 ASTM A-369 ASTM A-387 ASTM A-387 ASTM A-508 ASTM A-542 ASTM A-542 ASTM A-542 ASTM A-542 ASTM A-542 ASTM A-542 ASTM A-542 ASTM A-542 ASTM A-542 ASTM A-542 ASTM A-691 | Plate Smls. tube Fittings Bar Forging Forging Smls. tube Smls. tube Fittings Fittings E.R.W. tube Smls. pipe Forging Forging Forged pipe Plate Plate Forging Plate Plate Plate Plate Plate Plate Plate Plate Plate Plate Fusion welded pipe | 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 ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| F21 T21 T21 P21 F21, Cl. 1 F21, Cl. 3 FP21 21, Cl. 1 3CR, Cl. 1 3CR, Cl. 2 | K31545 K31545 K31545 K31545 K31545 K31545 K31545 K31545 K31545 K31545 | ASTM A-182 ASTM A-199 ASTM A-213 ASTM A-335 ASTM A-336 ASTM A-336 ASTM A-369 ASTM A-387 ASTM A-691 ASTM A-691 | Forging Smls. tube Smls. tube Smls. pipe Forging Forging Forged pipe Plate Fusion welded pipe Fusion welded pipe | ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| WC9 CP22 | J21890 J21890 | ASTM A-217 ASTM A4-426 | Casting Centrifugal cast pipe | ASME BPVC ASME BPVC |
| 10 | J22090 | ASTM A-356 | Casting | ASME BPVC |
| 8, Cl. A 8, Cl. B 8, Cl. C | J22091 | ASTM A-487 ASTM A-487 ASTM A-487 | Casting Casting Casting | ASME BPVC ASME BPVC ASME BPVC |
| CP21 | J31545 | ASTM A-426 | Casting | ASME BPVC |