| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a steel product having high hardness and high toughness after quenching and low-temperature tempering. <P>SOLUTION: Steel has a composition containing, by mass%, 0.30-0.65% C, 0.20-1.00% Si, 0.20-0.60% Mn, ≤0.030% P, ≤0.030% S, 1.00-3.00% Cr, 0.005-0.200% Al, ≤0.0200% N, ≤0.0030% O and further, one or more kinds of 0.50-2.00% Ni, 0.05-1.00% Mo, 0.0005-0.0050% B, 0.010-0.200% Ti and 0.010-0.100% Nb, and the balance Fe with inevitable impurities. In the method for manufacturing the high hardness and high toughness steel, the steel where 4Si+3Cr-Mn satisfies ≥6.00% is subjected to quenching at 800-900°C repeatedly two or more times and then is subjected to tempering at 400-650°C, and further, is subjected to quenching at 800-900°C and then is subjected to tempering at 100-250°C, and the high hardness and high toughness steel is produced. <P>COPYRIGHT: (C)2013,JPO&INPIT |
