| 摘要 |
PURPOSE:To produce a high hardness high Cr roll having excellent resistance to wear and accident and having an outside layer of >=85Hs by subjecting a three- layered roll casting consisting of an outside layer of a high Cr cast iron material, and intermediate layer and a core material to a high temp. heat treatment by medium frequency heating then to hardening at a high cooling rate and further tempering the casting at a prescribed temp. CONSTITUTION:The melt of an outside layer consisting of a high Cr cast iron material contg, by weight %, 2.5-3.2 C, 0.5-1.5 Mn, <=0.08 P, <=0.06 S, 1.0-3.0 Ni, 10-23 Cr, 0.5-3.0 Mo and 0.2-1.0 V is centrifugally cast. An intermediate molten steel contg. 1.0-0.25 C, 0.5-1.5 Si, 0.5-1.5 Mn, <=0.1 P and <=1.5 Ni is centrifugally cast on the outside layer and after the solidification, the melt of a core material consisting of a specifically composed ductile cast iron material is cast thereon. The resulting three-layered roll is subjected to a high temp. treatment at 950-1,100 deg.C by medium frequency heating then to hardening at a cooling rate of >=125 deg.C/hr followed by tempering at 400-600 deg.C, whereby the intended high hardness high chromium roll is obtd. |
