| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a case hardening steel which is suppressed in abnormal grain growth in carburization treatment and is thereby prevented in deterioration of characteristics by abnormal grain growth.SOLUTION: A case hardening steel has a composition comprising, by mass%, 0.10-0.30% C, 0.01-1.50% Si, 0.40-1.50% Mn, 0.01-0.10% S, 0.03% or less P, 0.05-1.00% Cu, 0.05-1.00% Ni, 0.01-2.00% Cr, 0.01-0.50% Mo, 0.001% or less Nb, 0.005-0.050% s-Al, 0.005-0.030% N, 0.001-0.150% Ti and/or 0.001-0.300% Zr and remaining Fe and unavoidable impurities, and the contents of Ti, Zr and N meet equation (1): [Ti]/47.9+[Zr]/91.2-[N]/14|/100≤3.5×10mol/g. The total deposition particle amount per 100 g steel material of TiC, Zr, C and AlN after hot rolling is 3.5×10mol or smaller.</p> |
