The main alloy grades of 6xxx series aluminum alloy automobile sheets include 6016, 6014, 6022, etc., which are the main aluminum alloy sheets currently used for body exterior panels. Automobile aluminum sheets have high requirements for comprehensive performance, surface quality and quality stability. The current mainstream aluminum alloy automobile sheet production process is relatively complex, including several major processes: melting, soaking, machining, hot rolling, cold rolling, and continuous heat treatment.
6xxx series aluminum alloy automotive sheets need to have good stamping and flanging performance, natural aging stability, good paint strength increment, and no Luoping lines on the surface of the material after stamping. To meet the special performance requirements of automotive sheets in automobile OEMs, not only qualified cold-rolled billets are required, but also special heat treatment technology and production equipment. The production capacity of aluminum alloy automotive sheets is mainly limited by this heat treatment technology and equipment.
Mainstream automotive sheet production process: semi-continuous casting (direct chill casting, DC) to produce large-sized aluminum flat ingots → sawing the head and tail → blasting the surface → heating → high-temperature rolling in a large wide hot rolling unit → coiling the aluminum billet → cold rolling to the finished thickness → heat treatment in an air cushion continuous heat treatment furnace dedicated to automotive sheet heat treatment equipment. If it is necessary to control the material microstructure and grain size, an intermediate annealing process can be added during the cold rolling pass.
