To obtain excellent corrosion resistance after working and in edge faces under specified salt damage environment conditions by forming a film at least contg. an alkaline-earth metal and oxygen on the part in which an iron base is exposed.
This hot dip aluminum plated steel sheet is the one excellent in corrosion resistance after working and in edge faces in the case a hot dip aluminum plated steel sheet in which an iron base exposed part is present is dipped into a 5% NaCl soln. under the opening to the air. Desirably, the thickness of a film contg. an alkaline-earth metal and oxygen to be formed on the iron base part is 100 to 3000 , and the alkaline-earth metal is composed of Mg. By allowing the film essentially consisting of Mg and O and moreover contg. Al and Si to exist on the surface of the plating, the dissolution (corrosion) of the plating layer can be suppressed. For forming this film, the method of incorporating the single substance or a compd. of the alkaline-earth metal into the plating film can be exemplified. When this film is present, its effect is remarkable in salt damage environments, particularly in wet environments.
MAKI JUN
ISAKI TERUAKI
KUROSAKI MASAO
SATO HISAAKI
