AL BASED PLATED STEEL SHEET EXCELLENT IN HIGH TEMPERATURE DISCOLORATION RESISTANCE AND PRODUCTION THEREOF

摘要

PURPOSE: To produce an Al based plated sheet steel excellent in discoloration resistance on the surface in the use in a high temp. environment by forming an Al based plated layer having a specified compsn. of three layers on the surface of a steel sheet. ;CONSTITUTION: An Al plated layer or an Al alloy layer constituted of Al and 1 to 30wt.% of one or more kinds among Si, Cr, Ti, Cu, Mn or the like is formed on the surface of a steel sheet by a hot-dip plating method, a nonaqueous electroplating method, a vacuum deposition method or the like. Next, it is heated in an oxidizing atmosphere, or by a vacuum deposition method by an electron beam heating system, an intermediate layer constituted of Al oxide having ≥0.1μm thickness is formed on the Al series alloy plated layer. Successively, an upper layer constituted of an Al vacuum-deposited layer with ≥1μm thickness having ≥99% Al purity is formed on the surface of the intermediate layer by a vacuum deposition method, and a chemically treated film essentially consisting of Al hydrated oxide is formed on the surface. The Al based plated steel sheet free from the discoloration of the surface even in the use in a high temp. environment can be obtd.;COPYRIGHT: (C)1995,JPO