PROCESS FOR PRODUCING HIGH-STRENGTH COLD-ROLLED STEEL SHEET

摘要

The invention provides a process for manufacturing cold rolled steel sheets containing silicon as a strengthening element so as to obtain excellent conversion treatment properties and post-painting corrosion resistance. For the production of high-strength cold rolled steel sheets containing 0.5 to 2.0 mass% silicon, a process for manufacturing high-strength cold rolled steel sheets is adopted which includes a pickling step of thermally annealing a steel sheet in a non-oxidizing atmosphere and thereafter pickling the steel sheet to dissolve away 0.5 g/m 2 to less than 2.0 g/m 2 of the steel sheet, and an electroplating step of electroplating the surface of the steel sheet after pickling with zinc under such conditions that a coating mass of 100 to 5000 mg/m 2 is obtained.