1. Carbon steel and low alloy steel
1.1 The hardness of carbon steel and low alloy steel is ≤22HRC, and the following conditions are met:
1. 1. 1 Nickel content <1%
1.1.2 It is necessary to release thermal stress caused by rolling, cold pressing or other manufacturing process, which is caused by permanent outer layer fiber deformation exceeding 5%. The minimum thermal stress release temperature is 595°C. According to the requirements of ASME Volume VIII, Division I. And meet one of the following heat treatment conditions:
a) hot rolling state
b) Annealed state
c) Normalizing state
d) Normalized and tempered state
e) Normalizing, austenitizing, quenching and tempering states
f) Austenitized, quenched and tempered state
1.2 ASTM A105 forging hardness ≤187HB.
1.3 It is forbidden to use free-cutting steel.
2. Austenitic stainless steel
2.1 The chemical composition of austenitic stainless steel meets the requirements in Table 1, and no cold working method is used to enhance its mechanical properties, and it is used at a maximum hardness of 22HRC after solution treatment, whether it is a casting or a forging. .
| C | 0.08% Max | Cr | 16% Min. |
| Ni | 8% Min. | P | 0.045% Max |
| S | 0.04% | Mn | 2.0% Max |
| Si | 2.0% Max |
2.2 High-alloy austenitic stainless steel with Ni%+2Mo%>30% and Mo%>2% is acceptable in solid solution state.
2.3 PREN>40 (Cr%+3.3(Mo%+0.5W%)+16N%>40%) High-alloy austenitic stainless steel is acceptable in solid solution state.
3. Duplex stainless steel
Duplex stainless steel is acceptable under solution annealing and liquid quenching, cold working conditions, ferrite composition 35~65%, age hardening heat treatment is prohibited.
