Hot-stamping tailor-welded blanks of aluminum sheet

Abstract

Forming a tailor-welded blank (TWB) having aluminum sheets includes various elements. For example, a hot-stamping methodology is applied to a welded blank for meeting load and stiffness requirements in tandem to weight efficiency. A TWB can result in improved material utilization, and applying the hot-stamping methodology can improve the formability of the TWB. After forming and subsequent processing, a peak-age heat treatment is utilized such that a lightweight, high strength part may be attained.

1 . A method of forming a tailor-welded blank (TWB) comprising:
 fabricating the TWB by welding a first sheet of aluminum to a second sheet of aluminum; and   improving a formability of a weld created by the welding by:
 heating the TWB to at least a solidus temperature of the first sheet; 
 positioning the TWB in a die set; and 
 closing the die set on the TWB to form the TWB into a part while simultaneously quenching the part. 
   
     
     
         2 . The method of  claim 1 , wherein the second sheet includes a different alloy than the first sheet. 
     
     
         3 . The method of  claim 2 , wherein respective series of the first sheet and the second sheet are selected from a group consisting of 2xxx, 5xxx, 6xxx, and 7xxx. 
     
     
         4 . The method of  claim 1 , wherein the second sheet includes a different thickness than the first sheet. 
     
     
         5 . The method of  claim 4 , wherein respective thicknesses of the first sheet and the second sheet are in a range of about 0.8 mm to about 4.0 mm. 
     
     
         6 . The method of  claim 1 , wherein fabricating the TWB includes fabricating a tailor-welded coil and blanking the TWB from the tailor-welded coil. 
     
     
         7 . A method of forming a tailor-welded sheet, which includes a first sheet of aluminum welded to a second sheet of aluminum, the method comprising:
 heating the tailor-welded sheet to at least a solidus temperature of the first sheet;   positioning the tailor-welded sheet in a die set; and   closing the die set on the tailor-welded sheet to form the tailor-welded sheet into a part while simultaneously quenching the part,
 wherein the part includes a first portion formed by the first sheet and a second portion formed by the second sheet, and 
 wherein the first portion and the second portion have different thicknesses. 
   
     
     
         8 . The method of  claim 7  further comprising, fabricating a tailor-welded sheet by welding the first sheet of aluminum to the second sheet of aluminum. 
     
     
         9 . The method of  claim 8  further comprising, blanking the tailor-welded sheet from a tailor-welded coil. 
     
     
         10 . The method of  claim 7 , wherein the first sheet of aluminum includes a first series of aluminum alloy and the second sheet of aluminum includes a second series of aluminum alloy, which is different than the first series. 
     
     
         11 . The method of  claim 10 , wherein the first series is selected from the group consisting of 2xxx, 5xxx, 6xxx, and 7xxxx series aluminum alloys, and wherein the second series is also selected from the group and is different than the first series. 
     
     
         12 . The method of  claim 7 , wherein the first sheet of aluminum includes a first thickness and the second sheet of aluminum includes a second thickness, which is different than the first thickness. 
     
     
         13 . The method of  claim 7  wherein the step of heating the tailor-welded sheet is performed outside of the die set, and the method further comprises the step of transferring the tailor-welded sheet to the die set after the step of heating the tailor-welded sheet and before the step of positioning the blank, wherein the steps of transferring the blank to the die set and positioning the blank in the die set is performed in about 30 seconds or less. 
     
     
         14 . The method of  claim 7 , wherein quenching the part includes cooling the part at a quench rate of at least 150° C./second. 
     
     
         15 . The method of  claim 7  further comprising, artificially aging the part to achieve a high strength temper. 
     
     
         16 . The method of  claim 7  further comprising, aging the part to achieve a T6 or T7x temper aluminum part. 
     
     
         17 . The method of  claim 7 , wherein the tailor-welded sheet is positioned in the die set such that the tailor-welded sheet does not touch the die set. 
     
     
         18 . A method of improving room-temperature formability of a weld that joins a first sheet of aluminum and a second sheet of aluminum to form a tailor-welded blank (TWB), the method comprising:
 heating the TWB to at least a solidus temperature of the first sheet;   positioning the TWB in a die set; and   closing the die set on the TWB to form the tailor-welded sheet into a part while simultaneously quenching the part.   
     
     
         19 . The method of  claim 18 , wherein respective series of the first sheet and the second sheet may be different and are selected from the group consisting of 2xxx, 5xxx, 6xxx, and 7xxx. 
     
     
         20 . The method of  claim 18 , wherein respective thicknesses of the first sheet and the second sheet are different and are in a range of about 4.0 mm to about 0.8 mm.