Heat resistant metal (steels) for pressurised applications: Low vanadium alloyed Cr-Mo-(Ni) steels with Mo ≤ 0.7 %, V ≤ 0.1 %, Cr ≤ 0,7 % and Ni ≤ 1,5 %
Features of heat-resistant low-alloyed chromium molybdenum steels ISO/TR 15608 group 4.2
This group contain heat-resistant low-alloyed chromium molybdenum steels (Type 0,5Cr-0,5Mo), in which chromium and molybdenum (in combination) give these steels improved creep strength and corrosion resistance at elevated temperatures.
Welding the steels is only possible with careful welding specifications (preheating temperature, defined heat input and post-weld heat treatment).
Generally speaking, grain size is reduced to reduce pearlite structure, increasing the material’s yield strength. Typical elements that are added to achieve this are titanium, copper, niobium and vanadium. The carbon content of HSLA steel can be anywhere between 0.05 and 0.25% (in mass content) in order to retain formability and weldability. Other elements include, but are not limited to, nickel, chromium, molybdenum and calcium. However, as low-alloy steels, the combined amount of alloying elements (excluding carbon) does mostly not exceed the limit of 2% in mass content.
Typical applications: Components for pressure equipments
Typical yield strength: 240 to 380 MPa
Low vanadium alloyed Cr-Mo-(Ni) steels with lower content of chromium and nickel: see Group 4.1
Typical materials in group 4.2
| Name / Grade | Number | Standard | Product | Remarks |
|---|---|---|---|---|
| T2 | K11547 | ASTM A-213 | Smls. tube | ASME BPVC |
| F2 T2 P2 FP2 | K12122 K12122 K12122 K12122 | ASTM A-182 ASTM A-250 ASTM A-335 ASTM A-369 | Forging E.R.W. tube Smls. pipe Forged pipe | ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
| 2, Cl. 1 2, Cl. 2 | K12143 K12143 | ASTM A-387 ASTM A-387 | Plate Plate | ASME BPVC ASME BPVC |
| 0.5CR, Cl. 1 0.5CR, Cl. 2 | K11547 K11547 | ASTM A-691 ASTM A-691 | Fusion welded pipe Fusion welded pipe | ASME BPVC ASME BPVV |
| 2, Cl. 1 2, Cl. 2 | K12765 K12765 | ASTM A-541 ASTM A-541 | Forging Forging | ASME BPVC ASME BPVC |
| CP2 | J11547 | ASTM A-426 | Centrifugal cast pipe | ASME BPVC |
| WC5 | J22000 | ASTM A-217 | Casting | ASME BPVC |