Physical properties
Chemical composition
Carbon C: 0.38 ~ 0.45 Si Si: ≤ 0.40 Mn Mn: 0.60 ~ 0.90 Sulfur S: to allow the residual phosphorus content ≤ 0.035 P: ≤ 0.035 to allow the residual content of chromium Cr: 0.90 ~ 1.20 Ni: to allow the residual content of ≤ 0.030 Copper Cu: allow the residual content ≤ 0.030 Mo Mo: 0.15 ~ 0.30 [2] ● 42CrMo4 Standard control: Chinese GB 42CrMo, Russia ГOCT 38XM, U.S. AISI 4140/4142, the British BS 708M40/708A42/709M40, France NF 40CD4/42CD4, German DIN 41CrMo4 / 42CrMo4, Japan JIS SCM4, the international ISO 683 / 1 3
Mechanical properties
Tensile strength σb (MPa): ≥ 1080 (110) yield strength σs (MPa): ≥ 930 (95) Elongation δ5 (%): ≥ 12 Reduction of area ψ (%): ≥ 45 impact energy Akv (J ): ≥ 63 impact toughness αkv (J/cm2): ≥ 78 (8) hardness: ≤ 217HB sample size: the size of the sample blank 25mm [3]
Standard heat treatment and microstructure
Standard heat treatment: quenching 850 ℃, oil cooling; tempering 560 ℃, water-cooled, oil-cooling. Microstructure: Tempered sorbite. Heat treatment: annealing annealing No.1 "760 ± 10 ℃ annealing, furnace cooling to 400 ℃ air-cooled. HB220-230 normalizing normalize No.4 860 ± 10 ℃ normalizing, baked cooled. Quenched quenching + tempering No.5 840 ± 10 ℃ quenching water or oil (depending on the product shape complexity) ,680-700 degree tempered. HB <217 quenching and quenching + tempering No.6 840 ± 10 ℃ quenching oil, 470 degrees and then tempered. HRC41-45 quenching quenching + tempering No.7 840 ± 10 ℃ quenching oil, 480 degrees and then tempered. HRC35-45 quenched quenching + tempering No.8 850 ℃ quenching oil, 510 degrees and then tempered. HRC38-42 quenched quenching + tempering No.9 850 ℃ oil quenching, tempering and then 500 degrees. HRC40-43 quenched quenching + tempering No.10 850 ℃ quenching oil, and then 510 ℃ tempered. HRC36-42 quenched quenching + tempering No .11 850 ℃ quenching oil, and then 560 ℃ tempered. HRC32-36 quenched quenching + tempering No.12 860 ℃ oil quenching, tempering and then 390 degrees. HRC48-52
