The effect of deep cold induced nano-carbides on the wear of case hardened components

Most studies of the wear improvements produced by the nano-carbides formed during deep cold treatment have been carried out on tool steels. In this study a carburising steel – 20MnCr5 – was carburised using typical industrial cycles, subjected to a range of cold treatments and its wear performance tested. It was found that under the conditions examined, converting any retained austenite to martensite increased wear. However, the nano-carbides formed by extended deep cold treatment at −196 °C did significantly improve wear. Deeper cold treatment at −269 °C did not produce any further improvement, even treatment for a much longer time.