MANUFACTURE OF VACUUM DEPOSITED GALVANIZED STEEL SHEET EFFICIENT IN ADHESION OF PLATED METAL

摘要

PURPOSE:To manufacture vacuum deposited galvanized steel sheet efficient in adhesion of plated metal, by a method wherein the cleaned surface of steel sheet is processed with the vacuum deposition of zinc by making the vacuum pressure of the atmosphere and the base sheet temperature at vacuum deposition conform to specified conditions. CONSTITUTION:The surface of steel sheet is continuously cleaned with reduction by its heat treatment at 650-900 deg.C in a reducing atmosphere containing hydrogen. Then, this cleaned surface is continuously processed with vacuum deposition of zinc under conditions conforming to the relations as shown in the formula (25logP+163<=T<=300) by making the atmospheric vacuum pressure P(Torr) and the base sheet temperature of vacuum deposition T( deg.C). Thus, the zinc plating shows minute uneveness composed of fine zine crystals on its surface and has efficient film adhesion properties.