HOT DIP ZINCING LEAD PLATING METHOD FOR STEEL

摘要

PURPOSE: To produce steel withstanding corrosion over a long period by forming a tin phosphate chemical film on steel, hot dip zincing it and thermal-spraying a lead alloy contg. a small amt. of antimony on the surface. ;CONSTITUTION: A primary stage in which the steel is hot dip zinced, a secondary stage in which a tin phosphate chemical film is formed on the surface, a third stage in which the steel is galvanized and a fourth stage in which a lead alloy contg. a small amt. of antimony is thermal-sprayed on the surface of the steel or the foil of the alloy is welded thereon to form a lead alloy layer having a desired thickness are combinedly executed. In this way, an antimony-lead alloy coating surface layer substantially free from pin holes and having high corrosion resistance can be formed into a desired thickness, and, by selecting the thickness, the stable steel withstanding corrosion over a long period, e.g. such as 300 years can be obtd.;COPYRIGHT: (C)1994,JPO&Japio