METHOD FOR PRODUCING ALUMINUM ALLOY SHEET BLANK FOR COLD PRESS FORMING HAVING COATING/BAKING HARDENABILITY, COLD PRESS FORMING METHOD USING THE BLANK, AND FORMED PART

摘要

PPROBLEM TO BE SOLVED: To achieve the coexistence of the securance of high formability and the improvement of coating/baking hardenability as an Al alloy sheet for cold press forming mainly used for an automotive body sheet. PSOLUTION: Using a blank made of an Al-Mg-Si based alloy sheet and having coating/baking hardenability with which a proof stress value is increased by 50 MPa upon artificial aging at 170C for 20 min after plastic deformation of 2% in a state where 10 days or more are passed through after solution treatment (concretely, a blank obtained by subjecting an Al-Mg-Si based alloy rolled sheet to solution treatment at 480C, rapidly cooling the sheet to a temperature range of 100C and performing preliminary aging treatment of holding the sheet to a temperature in the range of 50 to 120C for 5 min), the prescribed region in the blank is decided as a partial heating region, and the region is subjected to partial heating treatment under the conditions in which a temperature rising rate upon the heating is 20C/sec and a heating arrival temperature is 180 to 300C, thus the region is restored and softened. PCOPYRIGHT: (C)2011,JPO&INPIT