An overview of the excess carburizing process

The recent trend towards more compact and higher–pedformance automotive components has increased the need for greater durability and reliability in valve train parts and other components that are required to have high levels of strength and wear resistance. In an effort to meet these requirements much attention has been focused on excess carburizing. This process provides greater wear resistance than the conventional carburizing methods that have been used to date. Excess carburizing is a surface–hardening process that is accomplished through carbon diffusion and is similar to conventional carburizing. It involves the precipitation of spheroidal carbides on the material surface in a carburizing process using a high carbon concentration. The diffusion of these hard carbides into the material has the advantage of providing superior wear resistance, in addition to the strength and toughness obtained with conventional carburizing processes. This paper presents an overview of the excess carburizing process and discusses the technical issues that must be addressed in applying this process to automotive components.