Production manner null of the high corrosion-resistant Characteristic aluminizing Cr content steel sheet which is superior in plated

摘要

PURPOSE:To obtain a highly corrosion resistant aluminized steel sheet excellent in adhesive strength of aluminizing layer by previously applying oxidation and reduction treatments to the surface of a steel sheet under respectively specified conditions at the time of applying hot dip aluminizing to the surface of a Cr-containing steel sheet. CONSTITUTION:A cold rolled sheet of Cr steel containing 10-25% Cr is depreased, annealed, pickled, ground, and then heated up to 400-600 deg.C in an oxidizing or weekly oxidizing atmosphere of 0.9-1.5 air ratio by means of a burner, by which a thin film of oxide composed essentially of Fe is formed on the surface of the steel sheet. Subsequently, heating is applied to the above steel sheet up to 700-950 deg.C in a reducing atmosphere to reduce the oxide on the steel-sheet surface, and then, a hot dip aluminizing layer is formed on the surface of the steel sheet by passing the steel sheet through a hot dip aluminizing bath while applying cooling to this steel sheet. Since the steel sheet itself contains Cr and has superior heat resistance and oxidation resistance and, further, the hot dip aluminizing layer is formed with superior adhesive strength, the aluminized steel sheet having high corrosion resistance can be obtained.