| 摘要 |
A case hardening steel includes a chemical composition containing C: 0.10 mass % to 0.35 mass %, Si: 0.01 mass % to 0.13 mass %, Mn: 0.30 mass % to 0.80 mass %, P: 0.02 mass % or less, S: 0.03 mass % or less, Al: 0.01 mass % to 0.045 mass %, Cr: 0.5 mass % to 3.0 mass %, B: 0.0005 mass % to 0.0040 mass %, Nb: 0.003 mass % to 0.080 mass %, N: 0.0080 mass % or less, Ti as an impurity: 0.005 mass % or less, and the balance being Fe and incidental impurities, and satisfying Formulae (1) and (2):;3.0[% Si]+9.2[% Cr]+10.3[% Mn]≧10.0 (1);3.0[% Si]+1.0[% Mn]<1.0 (2)where [% M] represents the content of element M (mass %). |
