Material Group 5.1 (such 25 CrMo 4): Cr-Mo steels (free of vanadium) with
C ≤ 0,35 %, 0,75 % ≤ Cr < 1,5 % and Mo ≤ 0,7 %;
Features creep resistant steels such as such as 25 CrMo 4 in ISO/TR 15608 Material Group 5.1
This Material group are creep and heat resistant special structural (1Cr–0.5Mo) 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 induced Cold Cracking.
It is mainly used in boiler and apparatus construction for boiler drums and pressure vessels and also for hydrogen applications. The materials are suitable for temperatures up to 500°C (570°C).
Weldability of typical (1Cr–0.5Mo) steels such as 25 CrMo 4 listed in ISO/TR 15608 Material Group 5.1
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. 100 – 150 °C and max. interpass 300-350 °C. After welding, these steels generally have to be PWHT e.g. 630 – 700°C /2h
Typical materials in group 5.1
| Name/Grade | Number | Standard | Product | Remark |
|---|---|---|---|---|
| 25CrMo4 25CrMo4 25CrMo4 | 1.7218 1.7218 1.7218 | EN 10216-2 EN ISO 683-2 EN 10269 | Seamless tube Bar (QT) Fasteners | EN 13445-2 & EN 13480-2 Fasteners EN 13445-2 & EN 13480-2 |
| 26CrMo4-2 | 1.7219 | EN 10216-4 | Seamless tube | EN 13445-2 |
| 42CrMo4 42CrMo4 | 1.7225 1.7225 | EN ISO 683-2 EN 10269 | Bar (QT) Fasteners | Fasteners EN 13445-2 & EN 13480-2 |
| 13CrMo4-5 13CrMo4-5 13CrMo4-5 13CrMo4-5 13CrMo4-5 F12, Cl. 1 T12 T12 P12 FP12 | 1.7335 1.7335 1.7335 1.7335 1.7335 K11562 K11562 K11562 K11562 K11562 | EN 10028-2 EN 10216-2 EN 10222-2 EN 10253-2 EN 10273 ASTM A-182 ASTM A-213 ASTM A-250 ASTM A-335 ASTM A-369 | Plate Seamless tube Forging Fittings Bar Forgings Smls. tube E.R.W. tube Pipes Forged 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 EN 13445-2 & EN 13480-2 ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| 13CrMo5-5 | 1.7338 | EN 10216-2 | Seamless tube | EN 13445-2 & EN 13480- |
| F12, Cl. 2 F12 | K11564 K11564 | ASTM A-182 ASTM A-336 | Forging Forging | ASME BPVC ASME BPVC |
| 13CrMoSi5-5 F11, Cl. 2 F11, Cl. 3 WP11, Cl. 1 WP11, Cl. 3 F11, Cl. 2 F11, Cl. 3 11, Cl. 4 F11, Cl. 1 T11 T11 T11 P11 P11 F11, Cl. 1 FP11 | 1.7336 K11572 K11572 – – K11572 K11572 K11572 K11597 K11597 K11597 K11597 K11597 K11597 K11597 K11597 | EN 10028-2 ASTM A-182 ASTM A-182 ASTM A-234 ASTM A-234 ASTM A-336 ASTM A-336 ASTM A-445 ASTM A-182 ASTM A-199 ASTM A-213 ASTM A-250 ASTM A-312 ASTM A335 ASTM A-336 ASTM A-369 | Plate Forging Forging Fitting Fitting Forging Forging Forging Forging Smls. tube Smls. tube E.R.W. tube Smls. & welded pipe Smls. pipe Forging Forged pipe | 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 |
| 12, Cl. 1 12, Cl. 2 1CR, Cl. 1 1CR, Cl. 2 | K11757 K11757 K11757 K11757 | ASTM A-387 ASTM A-387 ASTM A-691 ASTM A-691 | Plate Plate Fusion welded pipe Fusion welded pipe | ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| 11, Cl. 1 11, Cl. 2 1.25CR, Cl. 1 1.25CR, Cl. 2 | K11789 K11789 K11789 K11789 | ASTM A-387 ASTM A-387 ASTM A-691 ASTM A-691 | Plate Plate Fusion welded pipe Fusion welded pipe | ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| B11 | K11797 | ASTM A-739 | Bar | ASME BPVC |
| WP12, Cl. 1 WP12, Cl. 2 | K12062 K12062 | ASTM A-234 ASTM A-234 | Fitting Fitting | ASME BPVC ASME BPVC |
| 10CrMo5-5 10CrMo5-5 | 1.7338 1.7338 | EN 10216-2 EN 10253-2 | Seamless tube Fittings | EN 13445-2 & EN 13480-2 EN 13445-2 & EN 13480-2 |
| CP12 | J11562 | ASTM A-426 | Centrifugal cast pipe | ASME BPVC |
| G17CrMo5-5 WC6 | 1.7357 J12072 | EN 10213 ASTM A-217 | Casting Casting | EN 13445-2 & EN 13480-2 ASME BPVC |