| 摘要 |
PROBLEM TO BE SOLVED: To obtain a surface treated steel sheet provided with a coating film having sufficient adhesive strength in a working part even if a retort treatment in high temp. steam is carried out after severe forming work by degreasing the steel sheet with an alkali and washing, picking and washing, electrolytically chromating and washing and drying the steel sheet before silane treatment is applied. SOLUTION: The steel sheet is surface treated by a series of processes for degreasing the steel sheet with the alkali and washing and next, pickling and washing, electrolytically chromating and washing and applying the silane treatment using a silane coupling agent. In the method, silane treatment is applied to the steel sheet dried after electrolytically chromated and washed. Where, the silane treatment is carried out so as to produce 2-6 g/m<2> silicon in a formed silane treatment film. The resultant surface treated steel sheet is excellent in working adhesion of the coating film and in the steel sheet coated with the thermoplastic resin, the coating film is not stripped after severe working. |
