Diffusion Borocarburizing of Steels

Abstract

Boriding is a thermo-chemical surface engineering technique used to offer extremely high hardness on different kinds of steels and its alloys. Boride surface modified steel alloys have wide range applications such as tools and different metal forming dies due to its better wear and corrosion properties. However, its usage in industrial scenario is restricted because of brittleness issues of borided case and core. Brittleness results in premature failure of engineering component when impact load is applied. Hence, the service life borided components are limited. Many techniques have been attempted by the researchers to reduce the brittleness of borided case and core. Boro-carburizing is one such a technique employed to reduce the brittleness by reducing the boron diffusion rate so that hard and brittle FeB phase formation is eliminated. Besides, this process offers better hardness gradient, better homogeneity, blunted needles at the interface, strengthening of core due to carbon enrichment. This paper presents the developments in boro-carburizing process.