SCM420 

 Executive Standard: JIS G4053-2003 

 ● Features and Scope: SCM420 alloy steel of high hardenability, non-temper brittleness, very good weldability, cold cracking tendency to form small, cutting and cold can be a good strain plasticity. SCM420 generally quenched or carburizing conditions used for the manufacture of non-corrosive medium and temperature lower than 250 ℃, the medium containing a mixture of nitrogen and hydrogen in high pressure pipe work and a variety of fasteners, the higher the infiltration Carbon parts such as gears and shafts. 
 SCM420 Alloy Steel 
 ● Chemical Composition: C: 0.18 ~ 0.23 Si Si: 0.15 ~ 0.35 Manganese Mn: 0.60 ~ 0.90 S S: to allow the residual phosphorus content ≤ 0.030 P: ≤ 0.030 to allow the residual content of chromium Cr: 0.90 ~ 1.20 Ni: to allow the residual content ≤ 0.25 Copper Cu: Mo to allow the residual content ≤ 0.030 Mo: 0.15 ~ 0.25 ● Mechanical Properties: Tensile σb (MPa): ≥ 885 (90) yield strength σs (MPa): ≥ 685 (70) Elongation δ5 ( %): ≥ 12 Reduction of area ψ (%): ≥ 50 Impact energy Akv (J): ≥ 78 impact toughness αkv (J/cm2): ≥ 98 (10) Hardness: ≤ 197HB sample size: the sample blank standard size 15mm ● Heat treatment and microstructure: heat treatment specifications: quenching 880 ℃, water, oil cooling; tempering 500 ℃, water-cooled, oil-cooling. ● Delivery status: to heat treatment (normalizing, annealing, or tempering) or heat treatment delivery, delivery status should be indicated in the contract.