Method For Manufacturing Aluminum Alloy Extruded Material

Abstract

The method for manufacturing an aluminum alloy extruded material using an aluminum alloy containing 20 to 95% by mass of a recycled aluminum material made by collecting and remelting extruded materials of aluminum alloys that are used or scrap materials generated in a manufacturing process, containing by mass: 6.0 to 8.0% of Zn, 1.0 to 2.0% of Mg, 0.10 to 0.50% of Cu, 0.10 to 0.25% of Zr, and 0.005 to 0.05% of Ti, with 0.30% or less of Si and 0.40% or less of Fe as impurities, and a balance being Al, includes cooling an extruded material at a cooling rate of 50 to 750° C./min from an extruded material temperature of 325 to 550° C. directly after extrusion, and thereafter performing two-stage artificial aging treatment at 90 to 130° C. for 1 to 8 hours and at 130 to 180° C. for 1 to 20 hours.

What is claimed is: 
     
         1 . A method for manufacturing an aluminum alloy extruded material using an aluminum alloy containing 20 to 95% by mass of recycled aluminum material made by collecting and remelting extruded materials of aluminum alloys that are used or scrap materials generated in a manufacturing process, containing by mass: 6.0 to 8.0% of Zn, 1.0 to 2.0% of Mg, 0.10 to 0.50% of Cu, 0.10 to 0.25% of Zr, and 0.005 to 0.05% of Ti, with 0.30% or less of Si and 0.40% or less of Fe as impurities, and a balance being Al, comprising:
 cooling an extruded material at a cooling rate of 50 to 750° C./min from an extruded material temperature of 325 to 550° C. directly after extrusion; and   thereafter performing two-stage artificial aging treatment at 90 to 130° C. for 1 to 8 hours and at 130 to 180° C. for 1 to 20 hours.   
     
     
         2 . The method for manufacturing an aluminum alloy extruded material according to  claim 1 , wherein the aluminum alloy further containing 0.35% or less of Mn and containing 0.25% or less of Sr is used. 
     
     
         3 . The method for manufacturing an aluminum alloy extruded material according to  claim 1 , wherein a tensile strength is equal to or more than 400 MPa, and a 0.2% yield strength is equal to or more than 380 MPa. 
     
     
         4 . The method for manufacturing an aluminum alloy extruded material according to  claim 2 , wherein a tensile strength is equal to or more than 400 MPa, and a 0.2% yield strength is equal to or more than 380 MPa.