Pin for chain and method for manufacture thereof

摘要

A chain pin manufacturing method of the invention requires only one heat treatment step of forming a boundary part composed of (V, Cr) ₈C₇ by Cr and C in a base material at first through a cementation process in a VCl atmosphere by using Cr-rich steel as the pin base material and of forming a surface layer composed of V₈C₇. A Cr content in the boundary part decreases gradually toward the base material and the surface layer and the boundary part is not clearly divided. Accordingly, as compared to a conventional chain pin manufacturing method which has required two steps of heat treatment of forming an intermediate layer by a chrome carbide layer and of forming a surface layer as a mixed layer of vanadium and chrome carbide layers, the inventive manufacturing method is simple and enables to manufacture the pin having high abrasion resistance and suitably used in a severe environment like a timing chain.