Research On Pretreatment Of Aluminum Alloy Sheets

Automotive light weighting can effectively save fuel consumption and reduce emissions,it is already become the preferred material because of aluminum and aluminum alloy's performance advantages. The experiment material of this research is 6016 aluminum alloy. It is heat-treated in the hot air circulation furnace. The effects of solution time and solution temperature on the dissolution of alloy phases, recrystallization, formability and the bake-hardening ability of cold rolled 6016 aluminum alloy, also the effects of pre-aging temperature within the range of 80~140?, pre-aging time within the range of l ~10min on the formability and the bake-hardening ability during paint baking of 6016 alloy sheets, which were holding at room temperature(RT) before pre-aging for 1min, 10 min respectively after solution, were examined integrally by means of metallographic microscopy, tensile, hardness and cupping test. The results are as follows:(1) After solid solution treatment of 6016 aluminum alloy sheet, the elongation, r and the n value are bigger than before, elongation and cup drawing value get the maximum value at 560 ?, r and n value of n are the maximum at 550 ?. the formability of sheet has increased dramatically when the solid solution temperature are 550 ? and 550 ?.(2) The yield ratio are changed of the 6016 aluminum alloy sheet after solid solution treatment, the minimum value is got at 560 ?, the hardness of 6016 aluminum alloy sheet get the maximum value at 560 ? after bake hardening treatment.(3) The excess phase dissolved quickly in the microstructure of 6016 aluminum alloy sheet after solid solution treatment, 560 ? is the fastest temperature.(4)In the test of solid solution time is constant, increased holding time, the sheet formability get best when the holding time is 5 min.(5)Through solid solution at room temperature after parking time of change, you can see that parking time shorter plate at room temperature performance is better than the long park 6016 plate at room temperature.(6)Test of 6016 aluminum alloy sheet after 550 ? x 5 min at room temperature for 5 min and after solid solution treatment, the best aging process for 120 ? x 7 min, after processing various performance indicators for the Re L: 145 Mpa, Rm: 257 Mpa, the elongation A: 26%, IE cup drawing value: 8.931 mm, n: 0.22, r: 0.703, after 170 ? by 30 min after hardening treatment of the lacquer that bake plank Re L: 173 Mpa, Rm: 277 Mpa.(7)Test of 6016 aluminum alloy sheet after 550 ? x 5 min at room temperature for 5 min and after solid solution treatment, the best aging process for 140 ? x 1 min, after processing various performance indicators for the Re L: 207 Mpa(rolling direction), 183 Mpa(rolling along 45 °), 184 Mpa(along the rolling 90 °).Rm: 244 Mpa(rolling direction), 228 Mpa(rolling along 45 °), 211 Mpa(along the rolling 90 °), elongation A: 26.83%(rolling direction), 22%(rolling along 45 °), 26%(along the rolling 90 °), cupping values IE: 8.41 mm, n: 0.22, r: 0.632.(8)Best of 6016 aluminum alloy car plate solid solution treatment and early aging process for: 550 ? water quenching after solid solution treatment 5 min, park again after 5 min at room temperature to 120 ?(7 min aging treatment, finally to 170 ?x 30 min of the lacquer that bake hardening treatment.