42CrMo the corresponding International Standards Organization Grade: 42CrMo4 corresponding to the Japanese brands: SCM440 for German Grade: 42CrMo4 similar to the corresponding U.S. trademark: 4140 ● Features and Scope: strength, high hardenability, toughness, and quenching of small deformation, high temperature high creep strength and rupture strength. Requirements for the manufacture of high strength steel than 35CrMo and quenched forging greater cross-section, such as a big locomotive traction gears, supercharger gear, rear axle, a great link by the load and spring, can also be used 2000m deep drill pipe joints and the following oil and fishing tools, and can be used for bending machine tooling. 

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 Chemical composition 
 Carbon C: 0.38 ~ 0.45 Si Si: 0.17 ~ 0.37 Manganese Mn: 0.50 ~ 0.80 S 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 ≤ 0.030 Copper Cu : allow the residual content ≤ 0.030 Mo Mo: 0.15 ~ 0.25 42CrMo 42CrMo allowable stress allowable stress 186 ~ 310/MPa, yield point 930σs/MPa, 42CrMo strength, high hardenability, toughness, quenching deformation, high temperature high creep strength and rupture strength. 42CrMo requirements for the manufacture of high strength steel than 35CrMo and quenched forging greater cross-section 

 Mechanical Properties 
 Tensile strength σb (MPa): ≥ 1080 (110) yield strength σs (MPa): ≥ 930 (95) Elongation δ5 (%): ≥ 12 Reduction of ψ (%): ≥ 45 [1] the impact energy Akv (J): ≥ 63 impact toughness αkv (J/cm2): ≥ 78 (8) Hardness: ≤ 217HB sample size: Sample size of 25mm rough 

 42CrMo heat treatment 
 Annealing annealing No.1 "760 ± 10 ℃ annealing, furnace cooling to 400 ℃ air-cooled. HB220-230 normalization 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 quenched and quenching + tempering No.6 840 ± 10 ℃ quenching oil, and then 470 degree tempered. HRC41-45 quenched quenching + tempering No.7 840 ± 10 ℃ quenching oil, and then 480 degree tempered. HRC35-45 quenched and quenching + tempering No.8 850 ℃ oil quenching, tempering and then 510 degrees. HRC38-42 quenching and 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 quenching oil 850 ℃, 560 ℃ and then tempered. HRC32-36 quenched quenching + tempering No.12 860 ℃ oil quenching, tempering and then 390 degrees. HRC48-52