| 摘要 |
PURPOSE:To produce a work roll for cold rolling having high quality and high reliability by specifying the shell material components of the work roll and successively subjecting the work roll to hardening and tempering treatments under specific conditions as a heat treatment. CONSTITUTION:A roll shaft core material is inserted into a metallic capsule in a manner as to form an annular space and high-C high-Cr tool steel powder is packed into the annular space. The powder contains, by weight, 1.5-3.0% C, 14.0-25.0% Cr and further 1.5-6.0% total of Mo and/or V as basic components. The material is then subjected to a hot hydrostatic press treatment in a high-temp. high-pressure gaseous atmosphere to densely sinter the powder and to unite the same with the core material. The molding is subjected to the heat treatment to harden the roll to 750-850 Hv surface hardness. The heat treatment is executed by heating and holding only the surface layer of the shell material in the body part consisting of the sintered powder layer to and at 1,050-1,200 deg.C, then cooling the same with gushing water to make progressive induction hardening and subjecting the material to at least >=2 times of the tempering treatment at 500-540 deg.C. The high-hardness roll having the high resistance to wear, failure and surface roughening is thus obtd.
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