Tailored rolling of high strength aluminum

Abstract

A method of processing high strength aluminum sheet is provided. The method may comprise uncoiling a coil of O or F-temper 6xxx or 7xxxx series aluminum alloy sheet, tailored rolling the sheet to form a tailored rolled sheet having at least two different thicknesses, blanking the tailored rolled sheet to form a tailored rolled blank (TRB), hot stamping the tailored rolled blank to form a component, and age hardening the component. The tailored rolling operation may reduce the thickness of the aluminum sheet by up to 60% in selected regions. The method may include a hot stamping process for age hardening aluminum alloys that solution heat treats and quenches the TRB. The method may be used to form lightweight, high-strength aluminum vehicle components having a controlled thickness profile to reduce component part weight.

What is claimed is: 
     
         1 . A method of processing high strength aluminum material comprising:
 uncoiling a coil of O or F-temper 6xxx or 7xxxx series aluminum alloy material;   tailored rolling the material to form a tailored rolled sheet having at least two different thicknesses along its length;   blanking the tailored rolled sheet to form a tailored rolled blank;   hot stamping the tailored rolled blank to form a component; and   age hardening the component.   
     
     
         2 . The method of  claim 1 , wherein the coil is a 7xxx series aluminum alloy material and the age hardening step includes heat treating the component to a yield strength of at least 490 MPa. 
     
     
         3 . The method of  claim 1 , wherein the coil is a 6xxx series aluminum alloy material and the age hardening step includes heat treating the component to a yield strength of at least 240 MPa. 
     
     
         4 . The method of  claim 1 , wherein the step of tailored rolling includes reducing a thickness of at least a region of the aluminum alloy material by up to 60%. 
     
     
         5 . The method of  claim 1 , wherein the 6xxx or 7xxx series aluminum alloy material has a thickness of 1 to 5 mm and the tailored rolled sheet has a thickness of 0.5 to 5 mm. 
     
     
         6 . The method of  claim 1 , wherein the hot stamping step includes:
 heating the tailored rolled blank to at least its solution temperature;   positioning the tailored rolled blank in a die set; and   closing the die set on the tailored rolled blank to form the blank into a component and quench the component.   
     
     
         7 . The method of  claim 1 , wherein the age hardening step includes heat treating the component to a T6 temper. 
     
     
         8 . The method of  claim 1 , wherein the age hardening step includes a two-step heat treatment of the component, including:
 a first heat treatment at 100 to 150° C. for 0.2 to 3 hours; and   a second heat treatment at 150 to 185° C. for 0.5 to 5 hours.   
     
     
         9 . The method of  claim 1  further comprising re-coiling the tailored rolled sheet into a coil prior to the blanking step. 
     
     
         10 . A method of processing a coil of high strength aluminum alloy comprising:
 uncoiling a coil of O or F-temper 7xxxx series aluminum alloy;   tailored rolling the coil to form a tailored rolled sheet having at least two different thicknesses along its length;   blanking the tailored rolled sheet to form a tailored rolled blank;   hot stamping the tailored rolled blank to form a component; and   age hardening the component to a yield strength of at least 490 MPa.   
     
     
         11 . The method of  claim 10 , wherein the step of tailored rolling includes reducing a thickness of at least a region of the aluminum alloy coil by up to 60%. 
     
     
         12 . The method of  claim 10 , wherein the coil of 7xxx series aluminum alloy has a thickness of 1 to 5 mm and the tailored rolled sheet has a thickness of 0.5 to 5 mm. 
     
     
         13 . The method of  claim 10 , wherein the hot stamping step includes:
 heating the tailored rolled blank to at least its solution temperature;   positioning the tailored rolled blank in a die set; and   closing the die set on the tailored rolled blank to form the blank into a component and quench the component.   
     
     
         14 . The method of  claim 10 , wherein the age hardening step includes heat treating the component to a T6 temper. 
     
     
         15 . The method of  claim 10 , wherein the age hardening step includes a two-step heat treatment of the component, including:
 a first heat treatment at 100 to 150° C. for 0.2 to 3 hours; and   a second heat treatment at 150 to 185° C. for 0.5 to 5 hours.   
     
     
         16 . The method of  claim 10 , wherein the 7xxx series aluminum alloy is a 7075 aluminum alloy. 
     
     
         17 . A method of processing high strength aluminum alloy sheet comprising:
 tailored rolling a sheet of 7xxxx series aluminum alloy to form a tailored rolled sheet having at least two different thicknesses;   blanking the tailored rolled sheet to form a tailored rolled blank;   hot stamping the tailored rolled blank to form a solution heat treated and quenched component; and   hardening the component to a yield strength of at least 490 MPa, by a first heat treatment at 100 to 150° C. for 0.2 to 3 hours and a second heat treatment at 150 to 185° C. for 0.5 to 5 hours.   
     
     
         18 . The method of  claim 17 , wherein the tailored rolling step includes reducing a thickness of at least a region of the aluminum alloy sheet by up to 60%. 
     
     
         19 . The method of  claim 17 , wherein the hot stamping step includes:
 heating the tailored rolled blank to at least its solution temperature;   positioning the tailored rolled blank in a die set; and   closing the die set on the tailored rolled blank to form the blank into a component while simultaneously quenching the component.   
     
     
         20 . The method of  claim 17 , wherein the 7xxx series aluminum alloy is a 7075 aluminum alloy.