| 摘要 |
A method of producing a hot-dip galvanized steel strip having a uniform zinc-iron alloy coating on one surface and a formable hot-dip metallic zinc coating on the opposite surface which comprises forming a thin uniform hot-dip metallic zinc coating which has a coating weight less than 0.10 ounces per square foot on one side and a heavier metallic zinc coating on the opposite surface and passing the coated strip through a chamber having heating means and cooling means therein, said heating means, such as gas jets, adapted to apply heat directly only to the thin zinc coated side of the strip to convert the thin zinc coating into a fully alloyed zinc-iron coating, and said cooling means, such as air jets, adapted to blow cooling air onto the heavier zinc coating to effect rapid cooling thereof while the thin zinc coated side is being heated; thereby preventing formation of a thick zinc-iron intermetallic subsurface layer on the heavier coated side. |
