Process for producing aluminum alloy for automobile body, and aluminum alloy

Abstract

In the production of an aluminum alloy plate for an automobile body, a molten alloy having an aluminum alloy composition of 3.00% by weight≦Mg≦3.50% by weight, 0.20% by weight≦Fe≦0.60% by weight, 0.10% by weight≦Si≦0.15% by weight, 0.01% by weight≦Ti≦0.05% by weight, Mn≦0.05% by weight and the balance of aluminum containing inevitable impurities is subjected to a liquid metal rolling to provide a plate material; the plate material is subjected to a cold rolling to provide a cold-rolled plate; and the cold-rolled plate is subjected to an annealing treatment at a temperature T set in a range of 340 ° C.≦T≦ 400 ° C. and for a period of time t set in a range of 9 hours≦t≦ 11 hours.

What is claimed is:  
     
         1 . A process for producing an aluminum alloy plate for an automobile body, comprising the steps of: 
 subjecting a molten alloy having an aluminum alloy composition of 3.00% by weight≦Mg≦3.50% by weight, 0.20% by weight≦Fe≦0.60% by weight, 0.10% by weight≦Si≦0.15% by weight, 0.01% by weight≦Ti≦0.05% by weight, Mn<0.05% by weight and the balance of aluminum containing inevitable impurities to a liquid metal rolling to provide a plate material;    subjecting said plate material to a cold rolling to provide a cold-rolled plate; and    subjecting said cold-rolled plate to an annealing treatment at a temperature T set in a range of 340° C.≦T≦400° C. and for a period of time t set in a range of 9 hours≦t≦11 hours.    
     
     
         2 . An aluminum alloy used for producing an aluminum alloy plate for an automobile body through a liquid metal rolling, a cold rolling and an annealing treatment, said aluminum alloy comprising 3.00% by weight≦Mg≦3.50% by weight, 0.20% by weight≦Fe≦0.60% by weight, 0.10% by weight≦Si≦0.15% by weight, 0.01% by weight≦Ti≦0.05% by weight, Mn<0.05% by weight and the balance of aluminum containing inevitable impurities.