| 摘要 |
PROBLEM TO BE SOLVED: To provide a producing method of a high tension hot dip galvanized steel sheet reduced in the unevenness in mechanical characteristics without containing much quantity of alloy elements. SOLUTION: After hot-rolling a steel material composed by wt.% of 0.12-0.20% C, <=0.50% Si, 0.8-2.0% Mn, 0.005-0.050% P, 0.0005-0.0100% S, 0.01-0.10% Sol.Al, 0.001-0.008% N and one or more kinds among 0.01-0.10% Ti, 0.001-0.050% Nb, 0.01-0.10% V and the balance Fe with inevitable impurities, this rolled steel is rolled at 400-750 deg.C to provide hot-rolled steel sheet. After pickling, cold rolling is executed at 40-80% draft, and after executing recystallize-annealing in theγrange not lower than the Ac3 transformation point, hot drip galvanizing treatment is applied. The steel containing 0.0005-0.0050% B in the steel components can give a better quality. After applying the hot dip galvanizing treatment, a galvannealing treatment may be applied.
|
