The invention relates to a production method of an aluminum
alloy profile for an automobile doorsill beam, which belongs to the field of
extrusion processing of aluminum
alloy doorsill beams and comprises the following steps: S1,
smelting, refining, slagging off, degassing, filtering and
casting into a cast
ingot with the
diameter of 250mm; s2, homogenizing treatment: keeping the temperature at 550-570 DEG C for 8-12 hours, and air-cooling to
room temperature; s3,
extrusion is conducted, specifically, a 3600 MN extruder and a 260 mm
extrusion container are adopted, the cast
ingot is heated in a segmented mode, the temperature of the extrusion container is controlled to be 440-460 DEG C, the temperature of a mold is controlled to be 480-500 DEG C, and extrusion is conducted at the speed of 1.5-1.7 m / min; s4,
quenching is conducted, specifically, three-stage online
quenching is conducted, and the
cooling rate of the aluminum
alloy profile is gradually reduced; s5, stretch straightening is conducted, specifically, two-stage straightening (pre-straightening and fine straightening) is conducted, and the total deformation rate is 0.8%; and S6,
artificial aging, wherein heat preservation is conducted for 5-7 h at the temperature of 170-180 DEG C. The Mg / Si ratio (1.1-1.3) is precisely regulated and controlled, and the
quenching and stretch straightening process is optimized, so that the
mechanical property, the
corrosion resistance and the extrusion
welding seam quality of the aluminum alloy profile are remarkably improved, and the aluminum alloy profile is suitable for the lightweight requirement of the automobile doorsill beam.