Research of Heat Treatment Process of AA6022 Aluminum Alloy Sheet Prepared by Electromagnetic Oscillation Twin Roll Casting

Based on the principle of sub-rapid solidification, AA6022 aluminum alloy sheets for automotive were successfully prepared by electromagnetic oscillation twin roll casting technology. In order to improve the comprehensive mechanical properties of the end products, the heat treatment process of the sheet was studied. Combined with OM, SEM, EBSD, macro hardness and tensile test, the effects of different heat treatment parameters on the microstructure and mechanical properties of sub-rapid solidification sheet were studied. The results show that the composite application of Al-Ti-B grain refiner and electromagnetic field can significantly improve the proportion of fine equiaxed grains. Solution + pre-aging treatment can significantly inhibit the natural aging hardening effect, enhance the natural aging stability of alloy sheet, and improve the tamping formability and paint hardening increment of alloy sheet. Under the optimized conditions (560 degrees Cx5 min+150 degrees Cx5 min+30 d at room temperature+175 degrees Cx30 min), the yield strength, tensile strength, elongation, macro hardness and plastic strain ratio of the sheet increase from 259 MPa, 296 MPa, 10.7%, 466.5 MPa and 0.66 of sample 1# to 296 MPa, 322 MPa, 16.1%, 599.8 MPa and 0.75 of sample 4#, respectively.