| 摘要 |
PROBLEM TO BE SOLVED: To produce a surface treated steel sheet highly balanced in corrosion resistance and workability and satisfying the other fundamental characteristics required for steel sheets mainly for automotive bodies and to provide a method for producing the same. SOLUTION: This surface treated steel sheet excellent in corrosion resistance and workability is the one in which, on the surface of a galvanized or galvannealed steel sheet, an amorphous inorganic film soluble in an acidic aq. soln., hard to dissolve in a neutral or alkaline aq. soln. and contg. >=5 wt.% Mg is formed by 0.1 to 2.0 g/m2. A zinc phosphate series chemical film may be interposed on the space between the plated steel sheet and the amorphous inorganic film. As the inorganic film, one or >= two kinds among phosphoric acid or the salts thereof, heavy phosphate, various condensed phosphoric acids or the salts thereof and organic phosphoric acid or the salt thereof are suitable. |
