| 摘要 |
PROBLEM TO BE SOLVED: To provide a phosphate-treated galvanized steel sheet which has improved bead sliding properties under the high facial pressure, and has excellent workability as well. SOLUTION: As a result of extensive investigation of the improvement of bead sliding properties under the high facial pressure in [a phosphate-treated galvanized steel sheet in which the crystal form of a phosphate film essentially consists of granular crystals] in the previous international public No.[WO01/11110 A1], the fact that the kind of surface control treatment performed prior to phosphate treatment plays an extremely important role is found. Namely, in the invention, phosphate crystals are formed on the surface of a galvanized steel sheet via the following stages (1) and (2) in this order: (1) the steel sheet is brought into contact with a surface control treatment agent consisting of the phosphate of polyvalent metal and acceleration components, and (2) the steel sheet is brought into contact with an Mg- containing phosphate treatment solution to form a phosphate film. COPYRIGHT: (C)2003,JPO
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