Method for manufacturing roll for reducing rolling, and roll for reducing rolling

Abstract

A method for manufacturing a roll for reducing rolling capable of suppressing the occurrence of fin flaws and edge flaws includes preparing a roll for reducing rolling for use on a three-roll type reducing-rolling mill. A ridge part ( 52 ) is formed in the adjacent portion between a caliber part and a flange part is rounded by cutting the ridge part ( 52 ) while rotating the roll for reducing rolling around the roll axis. In rounding the ridge part, in a ridge part region (RA 52 ) within the range of 3.0 mm in a roll axis direction with the top of the ridge part ( 52 ) being the center, the average of radiuses of curvature measured at a 0.5 mm pitch is made in the range of 2.5 to 3.0 mm, and the difference between the maximum value and the minimum value of the radiuses of curvature is made at most 1.0 mm.

1 . A method for manufacturing a roll for reducing rolling, which roll is used on a three-roll type reducing-rolling mill for reducing-rolling steel pipes, and comprises a caliber part having a groove of an arched shape in transverse cross section and flange parts adjacent to the caliber part, comprising the steps of:
 preparing the roll for reducing rolling; and   rounding a ridge part formed in the adjacent portion between the caliber part and the flange part by cutting the ridge part while rotating the roll for reducing rolling around the roll axis, wherein   in the step of rounding the ridge part,   in a ridge part region within the range of 3.0 mm in a roll axis direction with the top of the ridge part being the center, the average of radiuses of curvature measured at a 0.5 mm pitch is made in the range of 2.5 to 3.0 mm, and the difference between the maximum value and the minimum value of the radiuses of curvature is made at most 1.0 mm.   
     
     
         2 . A roll for reducing rolling which is used on a three-roll type reducing-rolling mill for reducing-rolling steel pipes, comprising:
 a caliber part having a groove of an arched shape in transverse cross section; and   flange parts adjacent to the caliber part, wherein   within the range of 3.0 mm in a roll axis direction with the top of a ridge part, which is formed in the adjacent portion between the caliber part and the flange part, being the center, the average of radiuses of curvature measured at a 0.5 mm pitch is in the range of 2.5 to 3.0 mm, and the difference between the maximum value and the minimum value of the radiuses of curvature is at most 1.0 mm.