| 摘要 |
PURPOSE:To improve the adhesion to plating and the powdering resistance by forming an alloyed zinc layer having a prescribed concn. of iron on the surface of a steel sheet contg. prescribed percentages of C, Mn, S, Al, Cr, Ni, etc. CONSTITUTION:A steel sheet consisting of, by weight, 0.02-0.3% C, 0.1-2% Mn, <=0.02% S, <=0.1% Al, one or more among <=0.3% Cr, <=0.5% Ni, <=0.5% Mo, <=0.5% W, <=0.5% V, <=0.01% B and 1% Cu and the balance Fe is rolled. The rolled steel sheet is hot dip galvanized and heated to the Ac1 transformation point - 850 deg.C. It is held at the temp. for >=1sec and cooled to 450 deg.C at >=10 deg.C/sec cooling rate. The concn. of iron in the resulting alloyed zinc layer on the surface of the steel sheet is regulated to 15-35%.
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