Chemical composition
C: 0.38-0.45
Si: 0.17-0.37
Mn: 0.50-0.80
Cr: 0.90-1.20
Mo: 0.15-0.25
P: ≤0.030
S: ≤0.030
Heat treatment
Specimen size: φ25mm
Quenching + tempering: 850℃ oil cooling + 560℃ oil cooling or water cooling
Mechanical properties of the specimen after the above heat treatment
Tensile strength Rm / Mpa: ≥1080
Yield strength Rp0.2 / Mpa: ≥930
Elongation A / %: ≥12
Section shrinkage Z / %: ≥45
Impact absorbed work Aku2 / J: ≥63
Hardness of annealed or high-temperature tempered steel HBW: ≤229