Production of thin flat articles with hardened surfaces

摘要

Thin metal articles of pre-determined shape are given a first treatment to provide a hardened surface and a second treatment to correct distortion caused by the hardening treatment. The hardening is provided an epsilon nitride layer and the corrective treatment is a heat treatment at 150 DEG to 600 DEG C., which will correct the distortion without reducing the hardness of the epsilon nitride layer.