Centrifugal cast caliber roll for hot rolling mill (as amended)

Abstract

A centrifugal cast caliber roll for a hot rolling mill has excellent abrasion resistance, fatigue resistance, and slip resistance. The roll has a chemical composition containing, by mass %, C: 1.8% or more and 3.0% or less, Si: 0.2% or more and 1.0% or less, Mn: 0.2% or more and 1.5% or less, Cr: 5% or more and 9% or less, Mo: 4.0% or more and 7.0% or less, V: 4.0% or more and 7.0% or less, Nb: 0.5% or more and 2.0% or less, and the balance being Fe and inevitable impurities, in which the relationship 0.6≦(C−0.24V−0.13Nb)≦1.4 (where C, V, and Nb each denote the content (mass %) of the corresponding chemical element) is satisfied, and has a surface hardness of Hs 67 or higher and Hs 76 or lower in terms of shore hardness.

1 . A centrifugal cast caliber roll for a hot rolling mill,
 the roll having a chemical composition containing, by mass %, C: 1.8% or more and 3.0% or less, Si: 0.2% or more and 1.0% or less, Mn: 0.2% or more and 1.5% or less, Cr: 5% or more and 9% or less, Mo: 4.0% or more and 7.0% or less, V: 4.0% or more and 7.0% or less, Nb: 0.5% or more and 2.0% or less, and the balance being Fe and inevitable impurities, in which relational expression (1) below is satisfied, and having a surface hardness of Hs 67 or higher and Hs 76 or lower in terms of Shore hardness:
   0.6≦(C−0.24V−0.13Nb)≦1.4  (1),
 
   wherein C, V, and Nb each denote the content (mass %) of the corresponding chemical element.   
     
     
         2 . The centrifugal cast caliber roll for a hot rolling mill according to  claim 1 , the roll being a rolling roll for a seamless steel pipe.