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Martensitic steel has high hardness, good wear resistance, and moderate corrosion resistance (better than carbon steel, weaker than austenitic 316L; suitable for neutral/weak corrosion, steam, and oil working conditions);
The forging process further enhances the density and impact toughness, eliminating casting defects.
American standard UNS: S42000
DIN/EN: 1.4021
Chinese standard GB: 2Cr13
element | C | Mn | Si | P | S | Cr | Ni |
scope | 0.15~0.25 | ≤1.00 | ≤1.00 | ≤0.040 | ≤0.030 | 12.0~14.0 | ≤0.75 |
Heat treatment state | Tensile strength Rm (MPa) | Yield strength Rp0.2 (MPa) | Elongation A50mm (%) | Brinell hardness HB(max) |
Annealed | ≥655 | ≥345 | ≥25 | 241 |
Quenching + Low-temperature tempering (204℃) | ~1600 | ~1360 | ~12 | 444 |
Quenching + Medium-temperature tempering (538℃) | ~1305 | ~1095 | ~15 | 375 |
Forging: Free forging/die forging must be used; Forging ratio ≥ 3, ultrasonic testing (UT) shall be carried out in accordance with ASTM A388, and Class I/II shall be qualified; Forging without cracks, inclusions, or folds
Heat treatment: Annealing at 815~845 ℃ for insulation, furnace cooling to 600 ℃ and then air cooling; Quenching and tempering treatment: oil quenching at 980-1010 ℃, tempering at 600-700 ℃
Mechanical processing: The surface roughness Ra of the flange sealing surface (RF/FF/RTJ) is ≤ 1.6 μ m; Bolt hole accuracy H12; The groove meets the requirements of ASME B16.5
Petrochemical industry: hydrogenation unit heat exchanger, reforming heat exchanger, steam generator
Electricity: condenser, feedwater heater
Pharmaceutical/Food: Clean steam heat exchanger (requiring surface treatment)
