HOT-DIP GALVANIZING

摘要

This invention provides a Bi-containing hot-dip galvanizing technique which can realize a Pb-free state and a Cd-free state in a hot-dip galvanizing layer and excellent plating quality. The Bi-containing hot-dip galvanizing is characterized in that the content of a Bi component in the plating layer is 0.05 to 5.00% by mass. The incorporation of the Bi component in a predetermined proportion in a plating bath can provide a plating layer which has excellent plating adhesion and corrosion resistance and good quality of product appearance without the addition of any Pb component. In particular, from the viewpoint of reducing environmental loading substances, the content of the Pb component and the content of the Cd component in the hot-dip galvanizing layer are preferably not more than 0.1% by mass and not more than 100 ppm, respectively, and ideally not more than 0.01% by mass and not more than 10 ppm, respectively. In order to reduce the Pb and Cd component contents each to a low level, the use of an electrolytic zinc metal as a zinc (Zn) metal is preferred.