Influence of copper on tempering a low-carbon chromium steel with and without small Nb or Ti additions

Abstract

The influence of 2% Cu on the tempering behavior of a low-carbon 4% Cr steel has been studied with and without small additions of Nb (0.09%) or Ti (0.21%) using hardness, optical and electron-microscopic techniques. Copper contributes significantly to precipitation hardening of Cr steel between 400 and 500°C. Addition of Nb or Ti enhances this hardening effect, which is established as essentially due to precipitation in the lath martensite of uniformly distributed spherical particles, presumably of copper. © 1974.