* SCM440,4140,4142,708M40,709M40,42CrMo4 Material comparison table (Chromium molybdenum steels) 1. Chemical composition Code KS JIS AISI AISI BS BS DIN Material Grade SCM440 SCM440 4140 4142 708M40 709M40 42CrMo4 C 0.38~0.43 0.38~0.43 0.38~0.43 0.40~0.45 0.36~0.44 0.36~0.44 0.38~0.45 Si 0.15~0.35 0.15~0.35 0.15~0.30 0.15~0.30 0.10~0.35 0.10~0.35 0.15~0.40 Mn 0.60~0.85 0.60~0.85 0.75~1.00 0.75~1...