| 摘要 |
PROBLEM TO BE SOLVED: To obtain a precoated steel sheet which has excellent formability and exhibits the excellent corrosion resistance even after this steel sheet is subjected to severe forming by applying final coating thereon after forming, then using such steel sheet. SOLUTION: This precoated steel sheet has chemical conversion treatment films on both surfaces of the galvanized steel sheet having a coating weight of >=15g/m<2> per one surface, has a primer coating film contg. >=1.0g/m<2> strontium chromate on the upper layer of the chemical conversion treatment film on one surface side of the steel sheet, has a finish coating film on the upper layer thereof and has a rear surface coating film contg. 1.0g/m<2> strontium chromate on the upper layer of the chemical conversion treatment film on the other surface side of the steel sheet. The elongation rate of the finish coating film described above is >=20%, the coefft. of dynamic friction of the front surface of the coating film is <=0.15 and the total of the strontium chromate contents in the primer coating film and the rear surface coating film is >=4.0g/m<2> . |
