And a method for manufacturing quality control method of steel sheet having an oxide film on the surface

摘要

PPROBLEM TO BE SOLVED: To provide a quality control method, capable of evaluating easily, quickly and accurately a thickness of an oxide film on a surface by an existing method, regarding a hot-dip galvanized plated steel sheet, an electro-zinc-plated steel sheet and a cold-rolled steel sheet having the oxide film on the surface, and to provide a manufacturing method for the steel sheets. PSOLUTION: This quality control method for the hot-dip galvanized steel sheet having the oxide film on the surface has a digitizing step for emitting an electron beam accelerated by an acceleration voltage selected out of a range of 0.1-5 kV toward the surface of the hot-dip galvanized steel sheet, and for measuring a signal intensity corresponding to a secondary electron amount generated in the surface to be digitized as a signal intensity value, and a determination step for determining the presence of the oxide film of a prescribed shape on the surface of the hot-dip galvanized steel sheet, based on whether the obtained signal intensity value is brought within a prescribed range. PCOPYRIGHT: (C)2005,JPO&NCIPI