Aluminum alloy plate and method for producing the same

Abstract

The present disclosure relates to an aluminum alloy plate having a composition containing Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50%, and Mn: more than 0.05% and 0.35% or less in terms of mass %, with the balance including Al and inevitable impurities.

What is claimed is: 
     
         1 . An aluminum alloy plate having a composition comprising Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50%, and Mn: more than 0.05% and 0.35% or less in terms of mass %, with a balance including Al and inevitable impurities. 
     
     
         2 . The aluminum alloy plate according to  claim 1 , wherein an intermetallic compound is present in the aluminum alloy plate, and a number density of the intermetallic compound having a circle equivalent diameter of 0.1 to 0.5 μm and not containing Cu is 1×10 6 /mm 2  or less. 
     
     
         3 . The aluminum alloy plate according to  claim 1 , wherein an intermetallic compound is present in the aluminum alloy plate, and a number density of the intermetallic compound having a circle equivalent diameter of 0.3 to 4 μm and containing Cu is 1×10 4  molecules/mm 2  or more. 
     
     
         4 . The aluminum alloy plate according to  claim 1 , wherein the composition contains Cu: 0.13 to 0.35 mass %. 
     
     
         5 . The aluminum alloy plate according to  claim 1 , wherein the composition further contains one or two of Ti: 0.05 mass % or less and B: 0.05 mass % or less. 
     
     
         6 . A method for producing an aluminum alloy plate having a composition containing Si: 0.03 to 0.35%, Fe: 0.03 to 0.35%, Mg: 3.0 to 5.0%, Cu: more than 0.09% and less than 0.50%, and Mn: more than 0.05% and 0.35% or less in terms of mass %, with a balance including Al and inevitable impurities, wherein the method comprises:
 subjecting an ingot obtained by casting an aluminum alloy material having the composition to homogenizing treatment at a first temperature within a range of 490 to 580° C.;   then cooling the ingot to a second temperature within a range of 430 to 500° C. and lower than the first temperature at an average cooling speed within a range of 500 to 3000° C./h;   starting hot-rolling while keeping the second temperature;   subsequently performing winding at a third temperature within a range of 320 to 380° C.; and   then sequentially performing cold-rolling and final annealing treatment.   
     
     
         7 . The method for producing an aluminum alloy plate according to  claim 6 , wherein
 the first temperature is within a range of 500 to 570° C.;   the second temperature is within a range of 440 to 490° C.; and   the third temperature is within a range of 340 to 360° C.