Method for making ferrous metal having highly improved resistances to corrosion at elevated temperatures and to oxidization

摘要

A method of making ferrous metal having highly improved resistances to corrosion and to oxidization, which comprises a step of hot-dipping a metallic workpiece in a molten aluminum or aluminum alloy bath, a step of primary heat-treatment of the metallic workpiece and a step of secondary heat-treatment of the metallic workpiece. During the primary heat-treatment, an intermetallic compound layer is formed over the surface of the metallic workpiece, which is developed into an alloy layer during the secondary heat-treatment to make the alloy layer firmly secured to the base of the workpiece. The secondary heat-treatment may be omitted depending on the application of the ferrous metal processed by this method.