PURPOSE: To form the fine rapidly cooling solidified structure and to improve the high temp. corrosion resistance and steam oxidizing resistance by executing the melting treatment by high energy ray on the surface after giving cold stress on the surface part of stainless steel.

CONSTITUTION: The stainless steel having ordinary crystal grain size and sufficient high temp. strength is prepared and given the working stress by a shot blast, cold rolling, peening working, etc. Next, at the time of applying the high energy ray, such as laser beam, etc., on this steel, only the surface layer contributing to working stress starts to melt in an extremely short time. Then, at the time of stopping the high energy ray irradiation, as the irradiation is on the above very thin melting layer, rapid cooling is executed by heat transfer to the base material, and the solidified structure is immediately formed. In this solidified structure, as the working stress is applied before the melting treatment, the crystal grain itself on the surface layer becomes extremely fine and the corrosion resistance of the surface is improved.