An experimental investigation on the mechanism of wear resistance improvement in cryotreated tool steels

Cryogenic treatment is an inexpensive one time permanent treatment that influences the entire section of the component. It is a supplementary process to conventional heat treatment process in steels. Though the benefits have been reported widely the degree of improvement experienced and the underlying mechanism are still debated upon. An attempt has been made to understand the basic mechanism of improvement in the wear resistance of cryogenically treated tool steels. The studies indicate that there is a minor increase in the hardness value of the cryogenically treated specimens. The optical microscopy study and X-ray diffraction pattern are discussed. A variation in the carbon content of the martensitic matrix, indicate that though there is no large scale formation of new carbides, there can be subtle clustering of carbides in the supersaturated martensite. This clustering taking place at sub-micron level and being very finely dispersed all over the matrix, is very hard to get characterised in the X-ray diffraction or optical microscopy studies. However, this could influence the wear resistance and hardness value resulting in the life improvement.