| 摘要 |
PURPOSE:To manufacture a corrosion resistant hot rolled steel sheet having high drawability at high productivity by subjecting a steel in which the content of C, N, Ti and Nb is regulated to hot rolling, taking-up and descaling in specified conditions, injecting the alloy powder of Zn or the like thereon and forming a hot-dip plated layer. CONSTITUTION:In a steel for a hot rolled steel sheet contg., by weight, <=0.05% C and <=0.001% N and in which the relationship of the content of C and N and the content of either or both of Ti and Nb lies in a one shown by the inequality, hot rolling is finished at the Ar3 transformation point or above, and the sheet is taken-up at 700 to 800 deg.C. Then, after its rolling at 600 to 800 deg.C, till the steel sheet is taken-up, scales on the surface of this steel sheet are removed by dry descaling or high pressure water descaling. Then, single metal of Zn, Al, Pb, etc., or the alloy therebetween, etc., is sprayed thereon in the steel sheet temp. higher than its m.p. in the range of 30 to 200 deg.C to form a hot-dip plated layer on the required face of the steel sheet. |
