Aluminum alloy extruded material and method for manufacturing the same

Abstract

An aluminum alloy extruded material having a composition containing Zn: 3.0 to 6.0% by mass, Mg: 0.4 to 1.4% by mass, Fe: 0.05 to 0.2% by mass, Cu: 0.05 to 0.4% by mass, Ti: 0.005 to 0.2% by mass, Zr: 0.1 to 0.3% by mass, and Cr: 0.050 to 0.160% by mass, the balance being Al and inevitable impurities. A conductivity is 40.1 to 44.3% IACS.

1 . An aluminum alloy extruded material having a composition comprising:
 Zn: 3.0 to 6.0% by mass,   Mg: 0.4 to 1.4% by mass,   Fe: 0.05 to 0.2% by mass,   Cu: 0.05 to 0.4% by mass,   Ti: 0.005 to 0.2% by mass,   Zr: 0.1 to 0.3% by mass, and   Cr: 0.050 to 0.160% by mass,   with the balance being Al and inevitable impurities,   wherein a conductivity is 40.1 to 44.3% IACS.   
     
     
         2 . The aluminum alloy extruded material according to  claim 1 , wherein a content of the Cr is 0.070 to 0.120% by mass. 
     
     
         3 . A method for manufacturing the aluminum alloy extruded material according to  claim 1 , the method comprising:
 preparing a billet having a composition comprising:
 Zn: 3.0 to 6.0% by mass, 
 Mg: 0.4 to 1.4% by mass, 
 Fe: 0.05 to 0.2% by mass, 
 Cu: 0.05 to 0.4% by mass, 
 Ti: 0.005 to 0.2% by mass, 
 Zr: 0.1 to 0.3% by mass, and 
 Cr: 0.050 to 0.160% by mass, 
 with the balance being Al and inevitable impurities; 
   heating the billet to 450 to 550° C.;   cooling the heated billet to 300° C. or lower at an average cooling rate of 90° C./hour or more;   reheating the cooled billet to 470° C. or higher to perform extrusion; and   quenching the extruded billet.   
     
     
         4 . A method for manufacturing the aluminum alloy extruded material according to  claim 2 , the method comprising:
 preparing a billet having a composition comprising:
 Zn: 3.0 to 6.0% by mass, 
 Mg: 0.4 to 1.4% by mass, 
 Fe: 0.05 to 0.2% by mass, 
 Cu: 0.05 to 0.4% by mass, 
 Ti: 0.005 to 0.2% by mass, 
 Zr: 0.1 to 0.3% by mass, and 
 Cr: 0.070 to 0.120% by mass, 
 with the balance being Al and inevitable impurities; 
   heating the billet to 450 to 550° C.;   cooling the heated billet to 300° C. or lower at an average cooling rate of 90° C./hour or more;   reheating the cooled billet to 470° C. or higher to perform extrusion; and   quenching the extruded billet.