posted on 2016-06-07, 00:00authored byJames A. Kargol, James B. Cundiff, Larry H. Lindberg, Peter A. Klobuchar, William C. Sievert
A process of consistently producing in an economical manner a galvanized steel strip having on one side a thin uniform surface coating of zinc-iron intermetallic compounds containing at least 6 percent iron and being free of metallic zinc and having on the other side a formable metallic zinc surface coating which is formed by continuously immersing the steel strip in a hot-dip zinc coating bath in which the temperature of the steel strip and the coating bath are controlled within a limited range to avoid forming an exclusively thick zinc iron intermetallic layer during hot-dip coating which interferes with good formability of the metallic zinc surface coating and controlling the thickness and uniformity of the zinc coating which is transformed into the coating formed of zinc-iron intermetallic compounds within a range of 10 to 30 g/m.sup.2 while maintaining the variation in coating weight within a range of from 3 to 6 g/m.sup.2 and heating the strip rapidly to a peak temperature of between about 482.degree. C. and 524.degree. C. within a period of 3 to 5 seconds and allowing the strip to cool below the melting point of the zinc coating.