Surface processing method for a steel member and surface processed steel member

摘要

A surface processing method, in which a thin plate steel member is stably solidified at desired surface portions and provides a high surface resistance against wearing, includes the steps of radiation of a high density energy beam to melt a processed portion of the steel member and rapid cooling subsequent to the radiation. The melted surface portion of the processed portion is constituted of a fully melted layer and an imperfectly melted layer adjacent thereto and melt in a short time within an austenitic transformation completion time. The high density energy beam may be divided to radiate plural regions to render the surfaces of the plural regions in a melting state at the same time. The thermal capacity (or thickness) of the entire steel member can be designed to be four times or more of the thermal capacity (depth of melted portion) of the processed portion, or the like to allow the steel member to enhance the cooling effect.