METHOD FOR REFORMING SURFACE OF METALLIC MATERIAL HAVING NO SOLID-PHASE TRANSFORMATION AND SURFACE-REFORMED METALLIC MATERIAL HAVING NO SOLID-PHASE TRANSFORMATION

摘要

PROBLEM TO BE SOLVED: To provide a method for reforming the surface of a metallic material having no solid-phase transformation, which gives fine crystal grain, and the surface-reformed metallic material having no solid-phase transformation.;SOLUTION: The surface-reformed metallic material having no solid-phase transformation has ≤15 μm average crystal grain diameter of the crystal grain at least near the surface. The surface reformation is beforehand performed, in which the stress is given on the surface of the metallic material having no solid-phase transformation and successively, this metallic material is rapidly cooled after rapidly heating. Then, the rapid heating and the rapid cooling are performed at one time or repeated at the plurality of times. Preferably, the giving stress rate is ≥5% and this stress can be given with a shot-peening. Further, this metallic material is heated with laser beam irradiation and further, the metallic material having no solid-phase transformation is a part to be worked.;COPYRIGHT: (C)2007,JPO&INPIT