SURFACE MATERIAL OF MOLD MOLDING SURFACE AND SURFACE TREATMENT METHOD OF MOLD MOLDING SURFACE

摘要

Provided are a surface material of a mold molding surface and a surface treatment method for obtaining the surface material which can achieve high hardness, improvement in corrosion resistance, and improvement in mold releasability of a mold surface with a relatively simple method of injecting powder or the like. At least a molding surface of a mold that is formed of metal or from a material including metal and in which the molding surface reaches 50°C or higher during molding is subjected to rapid thermal processing by injecting a substantially spherical shot which has a hardness that is equal to or greater than the surface hardness of the mold and has a size of #220 (JIS R6001-1973) or smaller at an injection pressure of 0.2 MPa or more and bombarding the molding surface with the shot, causing the temperature to rise locally and instantaneously at a bombarded portion to refine the surface structure of the molding surface and to form numerous smooth arc-shaped indentations on the entire surface of the molding surface. Then, powder comprising titanium or titanium alloy having a size of #100 (JIS R6001-1973) or smaller is injected at an injection pressure of 0.2 MPa or more to form a coating of titanium oxide on the surface of the molding surface.