PURPOSE: To produce a high hardness adamite roll of superior quality at a low cost by originally adding a specific heat treatment means to a composite roll of which the shell part consists of an adamite material and the shaft core part of a spheroidal graphite cast iron material.
CONSTITUTION: A shell part is cast of an adamite material and a shaft core part of a spheroidal graphite cast iron material, whereby a composite roll material which is stuck by these into one body by fusion is obtained. This roll material is subjected to diffusion annealing of heating the entire part of the roll at about 950W1050°C and spheroidizing annealing treatment at above its A1 transformation point and within about 200°C from the A1 transformation point. Thence, it is hardened by maintaining only the shell part at hardening temp. through quick heating and the shaft core part in the temp. state below the A1 transformation point, and cooling only the shell part through force air cooling or spray water cooling, after which it is tempered at about 500W600°C. Thereby, the hardness of the shell part is controlled to a 60W 75Hs range.
HASHIMOTO TAKASHI
FUNAKOSHI ATSUSHI
