Aluminum alloy sheet for automobile structural member use, automobile structural member, and method for producing aluminum alloy sheet for automobile structural member use

Abstract

Provided are: an aluminum alloy sheet for automobile structural member use having strength, formability, crushing properties, and corrosion resistance at excellent levels with balance; an automobile structural member; and a method for producing an aluminum alloy sheet for automobile structural member use. The aluminum alloy sheet for automobile structural member use is an Al—Mg—Si aluminum alloy sheet containing, in mass percent, 0.4% to 1.0% of Mg, 0.6% to 1.2% of Si, and less than 0.7% of Cu, with the remainder consisting of Al and impurities. The aluminum alloy sheet has an earing rate of −10.0% to −3.0%.

1 . An aluminum alloy sheet, the aluminum alloy sheet being an Al—Mg—Si aluminum alloy sheet comprising, in mass percent:
 0.4% to 1.0% of Mg; 
 0.6% to 1, 2% of Si; and 
 less than 0.7% of Cu, 
 wherein the aluminum alloy sheet has an earing rate of −10.0% to −3.0%. 
 
     
     
         2 . The aluminum alloy sheet of  claim 1 ,
 wherein the aluminum alloy sheet comprises, in mass percent, 0.4% to 0.6% of Mg.   
     
     
         3 . The aluminum alloy sheet of  claim 1 ,
 wherein the aluminum alloy sheet comprises, in mass percent, 0.6% to 0.8% of Si.   
     
     
         4 . The aluminum alloy sheet of  claim 1 ,
 wherein the aluminum alloy sheet has a bake hardenability so as to have a 0.2% yield strength of 215 MPa or more after being subjected to artificial aging at a temperature of 180° C. for 20 minutes.   
     
     
         5 . An automobile structural member, derived from the aluminum alloy sheet of  claim 1 . 
     
     
         6 . A method for producing an aluminum alloy sheet, the aluminum alloy sheet being an Al—Mg—Si aluminum alloy sheet, the method comprising:
 casting; 
 homogenizing; 
 hot rolling; 
 cold rolling; 
 annealing; 
 solutionizing; and 
 quenching, 
 the casting being performed on an aluminum alloy comprising, in mass percent:
 0.4% to 1.0% of Mg; 
 0.6% to 1.2% of Si; and 
 less than 0.7% of Cu, 
 
 wherein the cold rolling is performed to a cold rolling reduction of 40% or more, and 
 wherein the annealing is performed at a heat treatment temperature of 275° C. or higher.