SNC631 
 Military Steel: SNC631 performance standards: JIS G4053-2003 
 Physical properties 
 Chemical Composition: 
 Carbon C: 0.27 ~ 0.35 Si Si: 0.15 ~ 0.35 Manganese Mn: 0.35 ~ 0.65 S S: to allow the residual phosphorus content ≤ 0.030 P: ≤ 0.030 to allow the residual content 
 SNC631 military Steel 
 Chromium Cr: 0.60 ~ 1.00 Nickel Ni: 2.50 ~ 3.00 Copper Cu: ≤ 0.030 to allow the residual content 
 Mechanical Properties: 
 Tensile strength σb (MPa): ≥ 980 (100) yield strength σs (MPa): ≥ 785 (80) elongation δ5 (%): ≥ 9 Reduction of area ψ (%): ≥ 45 Impact energy Akv (J ): ≥ 63 impact toughness αkv (J/cm2): ≥ 78 (8) Hardness: ≤ 241HB sample size: Sample size of 25mm rough 
 Heat treatment and microstructure specifications: 
 Standard heat treatment: quenching 820 ℃, 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. 
 Feature 
 Carbon alloy quenched and tempered steel. High strength, high toughness and high hardenability. In the quenched state, good mechanical properties, good low temperature impact toughness. A tendency to temper brittleness, water easy to crack. Machinability is good, but poor weldability. Used in the quenched state. Edit this paragraph Application example 
 For the manufacture of forging and cold pressing and important section of a larger size of the quenched parts, such as connecting rod, disc, crankshafts, gears, shafts, screws, etc.