| 摘要 |
PURPOSE:To obtain a galvanized steel plate having excellent resistance to corrosion exfoliation by dipping a steel plate in an Al-contg. Zn bath having a specified component compsn. to form an alloy layer then dipping the same in a Pb-contg. Zn bath to form a plating layer. CONSTITUTION:A steel plate is dipped in the 1st molten metal bath consisting of 0.1-0.5% Al, and the balance Zn and unavoidable impurities to form an alloy layer consisting of an Fe-Al alloy and an Fe-Zn intermetallic compd. on the surface. The steel plate is then dipped in the 2nd molten metal bath consisting of <=0.3% Pb, and the balance Zn and <=0.07% Al and unavoidable impurities to form a Zn-Pb plating layer on the alloy layer. If the Al in the 1st bath is increased as desired in this method, the adhesion of the plating layer is improved without worry over trouble such as corrosion exfoliation. |
