Precipitation hardening behavior of v and/or Cu bearing middle carbon steels

Abstract

Synopsis : In this study, the precipitation hardening behavior of middle carbon steels with single and multiple additions of 0.3mass%V and 2mass%Cu has been investigated. The precipitation treatment was carried out isothermally at 550°C, 600°C and 650°C. In the 0.3mass%V bearing steel, precipitation hardening was observed at 600°C and 650°C while no significant increase in hardness was observed at 550°C. When 2mass% Cu was added to the 0.3mass%V bearing steel, the hardness attributed to the precipitation hardening of Cu was added to that attributed to the precipitation hardening of VC in the cases of 600°C and 650°C. In the case of 550°C, the V addition into the Cu bearing steel markedly increased the hardness although the precipitation hardening of VC was hardly observed in the 0.3mass%V bearing steel. In the paper, the different precipitation hardening behavior of the three steels is discussed in detail in consideration of the observed precipitation behavior.