| 摘要 |
PURPOSE:To increase the rate of cooling and quench hardened layers by supplying cooling water into the central inside hole of a work roll for cold rolling of specified contents of C, Cr and the diameter of the central inside hole which is heated to high temp. to cool said roll down to specific temp. then cooling the surface of the roll with water. CONSTITUTION:In the stage of surface hardening of a work roll for cold rolling which consists of steel contg. 0.6-1.3wt% C and 2.0-6.0wt% Cr and has a central inside hole of 60-160phimm., cooling water is first supplied to the central inside hole of the roll heated to high temp. to cool the surface layer to be the quench hardened layer of the roll surface down to the temp. just prior to attainment of the Ar1 transformation point, that is, 500-700 deg.C, so that the quantity of the heat contained in the roll is reduced as far as possible. The surface of the roll is cooled with water by which the surface is hardened. Thus the roll of always stable and high quality is obtained. |
