Chain for use in automobile engine

摘要

Connecting pins in a roller chain are chromized by a diffusion penetration treatment, that results in inner and outer chromium carbide layers on the steel base material. The inner layer contains Cr₇C₃, and the outermost layer, which is thinner than the inner layer, contains Cr₂₃C₆. The surface roughness of the outer layer is reduced by barrel polishing, without removal of all of the Cr₂₃C₆-containing layer.