A METHOD OF COATING A STEEL SUBSTRATE

摘要

A non-alloy steel is treated to provide a good keying surface for a solid polymeric or wax coating by heat treatment at 550 to 720 deg C for up to 4 hours in an atmosphere of, eg ammonia and endothermic or exothermic gas, followed by cooling to produce an epsilon iron nitride surface layer. The solid coating adheres tenaciously to the surface layer to give excellent salt spray resistance.