Aluminum alloy sheet for press forming, process for manufacturing same, and press-formed product thereof

Abstract

An aluminum alloy sheet for press forming includes an aluminum alloy including 0.4 to 1.5 mass % of Si and 0.3 to 1.0 mass % of Mg, with the remainder being Al and inevitable impurities. With respect to diagonal lengths of indentations formed therein with a Vickers hardness tester, a proportion P (%) of a difference ΔL between a length L0 of a diagonal which forms an angle of 0° with a rolling direction and a length L45 of a diagonal which forms an angle of 45° with the rolling direction to the L0 is 2.0% or less.

1 . An aluminum alloy sheet for press forming, comprising:
 an aluminum alloy comprising 0.4 to 1.5 mass % of Si and 0.3 to 1.0 mass % of Mg, with the remainder being Al and inevitable impurities,   wherein with respect to diagonal lengths of indentations formed therein with a Vickers hardness tester, a proportion P (%) of a difference ΔL between a length L0 of a diagonal which forms an angle of 0° with a rolling direction and a length L45 of a diagonal which forms an angle of 45° with the rolling direction to the L0 is 2.0% or less.   
     
     
         2 . The aluminum alloy sheet for press forming according to  claim 1 , wherein the aluminum alloy further comprises at least one of the following:
 1.0 mass % or less of Cu;   at least one of 0.5 mass % or less of Fe and 0.5 mass % or less of Mn;   at least one of 0.3 mass % or less of Cr, 0.3 mass % or less of Zr, and 0.3 mass % or less of Ti; and   0.5 mass % or less of Zn.   
     
     
         3 . The aluminum alloy sheet for press forming according to  claim 1 , wherein the aluminum alloy comprises 0.6 mass % to 1.3 mass % of Si and 0.3 mass % to 0.8 mass % of Mg. 
     
     
         4 . An aluminum alloy press-formed article produced by press-forming the aluminum alloy sheet according to  claim 1 . 
     
     
         5 . An aluminum alloy press-formed article produced by press-forming the aluminum alloy sheet according to  claim 3 . 
     
     
         6 . A process for producing an aluminum alloy sheet, comprising:
 casting an aluminum alloy comprising 0.4 mass % to 1.5 mass % of Si and 0.3 mass % to 1.0 mass % of Mg, with the remainder being Al and inevitable impurities;   subjecting a slab of the aluminum alloy to a homogenizing heat treatment;   hot-rolling the aluminum alloy, at a hot rolling ending temperature of 300° C. or lower;   annealing the aluminum alloy at a temperature of 300° C. to 500° C.,   cold-rolling the aluminum alloy at a cold rolling ending temperature of 100° C. or lower;   subjecting the aluminum alloy to a solution treatment step at a temperature of 500° C. or higher; and   heating the aluminum alloy to a temperature of 70° C. or higher.   
     
     
         7 . A process for producing an aluminum alloy sheet for press forming, comprising:
 casting an aluminum alloy comprising 0.4 mass % to 1.5 mass % of Si and 0.3 mass % to 1.0 mass % of Mg, with the remainder being Al and inevitable impurities;   subjecting a slab of the aluminum alloy to a homogenizing heat treatment;   hot-rolling the aluminum alloy;   cold-rolling the aluminum alloy at a cold rolling ending temperature of 100° C. or lower;   intermediate annealing the aluminum alloy at a temperature of 300° C. to 500° C.;   cold-rolling the aluminum alloy at a cold rolling ending temperature of 100° C. or lower;   subjecting the aluminum alloy to a solution treatment at a temperature of 500° C. or higher; and   heating the aluminum alloy to a temperature of 70° C. or higher.   
     
     
         8 . The process for producing an aluminum alloy sheet for press forming according to  claim 6 , wherein the aluminum alloy further comprises at least one of the following:
 1.0 mass % or less of Cu;   at least one of 0.5 mass % or less of Fe and 0.5 mass % or less of Mn;   at least one of 0.3 mass % or less of Cr, 0.3 mass % or less of Zr, and 0.3 mass % or less of Ti; and   0.5 mass % or less of Zn.   
     
     
         9 . The process for producing an aluminum alloy sheet for press forming according to  claim 6 , wherein the aluminum alloy comprises 0.6 mass % to 1.3 mass % of Si and 0.3 mass % to 0.8 mass % of Mg, with the remainder being Al and inevitable impurities. 
     
     
         10 . The process for producing an aluminum alloy sheet for press forming according to  claim 8 , wherein the aluminum alloy comprises 0.6 mass % to 1.3 mass % of Si and 0.3 mass % to 0.8 mass % of Mg, with the remainder being Al and inevitable impurities. 
     
     
         11 . The aluminum alloy sheet for press forming according to  claim 2 , wherein the aluminum alloy comprises 0.6 mass % to 1.3 mass % of Si and 0.3 mass % to 0.8 mass % of Mg, with the remainder being Al and inevitable impurities. 
     
     
         12 . An aluminum alloy press-formed article produced by press-forming the aluminum alloy sheet for press forming according to  claim 2 . 
     
     
         13 . An aluminum alloy press-formed article produced by press-forming the aluminum alloy sheet for press forming according to  claim 11 . 
     
     
         14 . The process for producing an aluminum alloy sheet for press forming according to  claim 7 , wherein the aluminum alloy further comprises at least one of the following:
 1.0 mass % or less of Cu;   at least one of 0.5 mass % or less of Fe and 0.5 mass % or less of Mn;   at least one of 0.3 mass % or less of Cr, 0.3 mass % or less of Zr, and 0.3 mass % or less of Ti; and   0.5 mass % or less of Zn.