多合金系白鋳鉄の高温硬さ及び熱間摩耗特性に及ぼす炭素及びニッケルの影響

抄録

  Abrasion wear resistance is most required for hot rolling mill rolls, and cast iron with high carbon content, which has hard carbides, is widely used to the rolls. In the rolling operation, the roll surface is heated by contact with high-temperature rolled steels and with friction heat by rolling load in the roll-bite. This causes the roll to wears under the high temperature. Until now the effect factors were evaluated based on the microstructure and hardness at room temperature because of convenience. In this study the effect of high temperature hardness and the microstructure were investigated for the multi-component white cast iron which has widespread in recent years. And Ni that increases the hardenability and the high temperature property was added. As a result, the wear resistance has strong correlation with carbides amount and micro-hardness in matrix structure. The correlation with hardness at high temperature hardness was the same as room temperature hardness. Hot wear was small for white cast alloys containing 1.5mass%C-Ni-free and 3mass%C-7.5mass%Ni. The former is thought to due to the high hardness martensite matrix and the latter due to the reinforcement of the matrix structure by adding Ni and the large amount of high hardness carbide in the multi-component white cast iron.