HOT DIP ALUMINUM COATED CHROMIUM ALLOY STEEL

摘要

Continuous hot dip aluminum coated ferritic chromium alloy steel strip. Strip is cleaned by heating to a temperature no greater than about 650.degree.C in a direct fired furnace. The cleaned strip is further heated in a protective atmosphere containing at least 95% by volume hydrogen, cooled in the protective hydrogen atmosphere to near or slightly above the melting point of an aluminum coating metal, and passed into a bath of the aluminum coating metal. The low direct fired furnace cleaning temperature and hydrogen protective atmosphere provides good wetting of a chromium alloy steel surface to prevent uncoated areas or pin holes in the aluminum coated layer.