Steel can be divided into low carbon steel, medium carbon steel and high carbon steel. Low carbon steel - carbon content is generally less than 0.25%; medium carbon steel - carbon content is generally between 0.25 and 0.60%; high carbon steel - carbon content is generally greater than 0.60%.
Executive standard: my country Taiwan CNS standard steel number S20C, German DIN standard material number 1.0402, German DIN standard steel number CK22/C22. British BS standard steel number IC22, French AFNOR standard steel number CC20, French NF standard steel number C22, Italian UNI standard steel number C20/C21, Belgium NBN standard steel number C25-1, Sweden SS standard steel number 1450, Spain UNE standard steel No. F.112, American AISI/SAE standard steel No. 1020, Japanese JIS standard steel No. S20C/S22C.
Chemical composition: Carbon C: 0.32～0.40 Silicon Si: 0.17～0.37 Manganese Mn: 0.50～0.80 Sulfur S: ≤0.035 Phosphorus P: ≤0.035 Chromium Cr: ≤0.25 Nickel Ni: ≤0.25 Copper Cu: ≤0.25 Fourth, mechanical properties : Tensile strength σb (MPa): ≥530 (54) Yield strength σs (MPa): ≥315 (32) Elongation δ5 (%): ≥20 Area shrinkage ψ (%): ≥45 Impact energy Akv ( J): ≥55 impact toughness value αkv (J/cm²): ≥69 (7) Hardness: unheated ≤197HB Sample size: sample size is 25mm Technical performance National standard: GB699-1999
