| 摘要 |
PURPOSE:To manufacture a work roll for heavy-load cold rolling excellent in spalling resistance and wear resistance by subjecting a steel having a composition consisting of C, Si, Mn, Cr, Ni, Mo, V, P, S, and Fe to forging and then to specific heat treatment. CONSTITUTION:A steel having a composition consisting of, by weight, 0.80-1.00% C, 0.10-0.65% Si, 0.20-1.60% Mn, 4.0-6.5% Cr, 0.10-0.70% Ni, <=0.30% Mo, <=0.10% V, <=0.25% P, <=0.010% S, and the balance Fe with inevi table impurities is forged into the prescribed roll shape. Subsequently, the forg ing is subjected to quench-and-temper treatment, by which toughness inside the roll is secured. The roll formed part is subjected to induction heating, by which the surface layer part is subjected to temp. rise up to 930-1,000 deg.C to undergo austenitizating and hardening treatment. Then, the roll is subjected to subzero treatment at 0--50 deg.C to produce sufficient hardness. Successively, the above roll is tempered at 110-150 deg.C. By this method, the work roll in which is Vickers hardness in the surface layer part exceeds HV 800 and the amount of residual austenite is regulated to >=5vol.% can be obtained. |
