| 摘要 |
PURPOSE:To obtain the titled steel sheet having superior coating performance, weldability and workability etc., by performing the alloy formation in a range where the relation between the steel sheet temp. and the time for alloy formation is specified after conducting the galvanization on a cold-rolled steel sheet composed of specific components such as C, Mn. CONSTITUTION:After conducting galvanization of cold-rolled steel sheet contg. 0.001-0.03wt% C, <=4.5wt% Mn, <=0.04wt% soluble Al, 0.02-0.3wt% Ti, <=0.5wt% Cr, <=0.25wt% Si, <=0.015wt% S, <=0.009wt% O (wherein the atomic concn. ratio of Ti/(C+N+C+O) being 0.8-2), and residual wt% Fe, the formation of the alloy in said galvanized layer is performed in the furnace kept at 500- 700 deg.C for 5-60sec under the condition that the relation between the temp. of the steel sheet and alloy formation is in the range surround by a trapezoid ABCD. Also, Si in the steel sheet is regulated to <=0.3wt% on occasion of regarding the adhesive property as important. |
