STEEL MATERIAL PLATED WITH ZINC-ALUMINUM ALLOY WITH SUPERIOR RESISTANCE TO STRIPPING DUE TO CORROSION AND ITS MANUFACTURE

摘要

PURPOSE:To manufacture the titled steel material by forming a layer of a molten alloy having a specified composition consisting of Al, Si, Mg and the balance essentially Zn by hot dipping, cooling the layer at a high cooling rate, and continuing cooling. CONSTITUTION:A steel material is dipped in a molten alloy consisting of, by weight, 5-24% Al, =0.8% Si, =0.5% Mg and the balance essentially Zn, and it is pulled up to form a layer on the surface. The layer is cooled at =17 deg.C/sec cooling rate until it is practically solidified, and cooling is continued so that the layer is not reheated to a temp. above the solidifying point by the residual heat of the steel material.