Structure-Property Correlation of Cryotreated AISI D2 Steel

Abstract

This study aims to reveal the underlying mechanism associated with the enhancement of wear resistance of tool steels by deep cryogenic treatment and to resolve the issue of reported varied degree of improvement in wear resistance through structure-property correlation of cryotreated vis-à-vis conventionally treated AISI D2 steel. Microstructures of heat treated specimens have been characterized employing various techniques with specific emphasis on quantitative estimation of the characteristics of secondary carbides. Evaluations of properties include measurements of bulk hardness, apparent strength of the matrix, fracture toughness and dry sliding wear resistance under wide rage of normal loads supplemented by in-depth characterizations of worn surfaces, wear debris and subsurfaces of worn specimens in order to identify the operative mode and mechanism of wear. It has been demonstrated that the favorable modifications of the precipitation behavior of secondary carbides in addition to removal of retained austenite are the governing mechanisms for the enhancement of wear resistance of tool steels by deep cryogenic treatment. The cause of the reported varied degree of improvement in wear resistance by deep cryogenic treatment has been explained by disparity of the operative modes and mechanisms of wear.