The invention relates to the production field of aluminum alloys, in particular to a method for restraining generation of an A7N01 aluminum
alloy surface coarse grain ring. During
alloy smelting, a trace
rare earth element, namely
scandium, is led in, the weight percentage of the
scandium is 0.05%-0.15%, and a
scandium contained A7N01 aluminum
alloy casting ingot is prepared. The
casting ingot is subject to homogenization treatment,
extrusion forming, online
air cooling and
natural aging treatment, the defect of the coarse grain ring on the surface of an
extrusion product is restrained, and the alloy
microstructure is obviously refined. An A7N01 aluminum alloy comprises, by
mass percentage, 4.0%-5.0% of
zinc, 1.0%-2.0% of
magnesium, not larger than 0.20% of
copper, 0.20%-0.7% of
manganese, not larger than 0.30% of
chromium, not larger than 0.25% of
zirconium, not larger than 0.20% of
titanium, not larger than 0.10% of
vanadium and the balance aluminum and inevitable impurities. According to the method, the trace
rare earth element, namely scandium, is led in, a wee dispersed nanoscale Al3(Sc,Zr) phase is generated in an A7N01 aluminum alloy
extrusion bar base, and the dispersion strengthening effect is achieved.