Formability of Aluminum Tailor-Welded Blanks 2000-01-0772
The use of tailor welded blanks (TWBs) in automotive applications is increasing due to the potential of weight and cost savings. These blanks are manufactured by joining two or more sheets of dissimilar gauge, properties, or both, to form a lighter blank of desired strength and stiffness. This allows an engineer to “tailor” the properties of the blank to meet the design requirements of a particular panel. TWBs are used in such places as door inner panels, lift gates, and floor pans. Earlier investigations of the use of TWBs targeted steel alloys, but the potential of further weight savings with aluminum TWBs is gaining interest in the automotive industry.
Unlike steel TWBs, the welds in aluminum TWBs are not significantly stronger than the base material and are occasionally the fracture site. Additionally, the reduced formability of aluminum, as compared with drawing-quality steels, makes the application of aluminum TWBs more difficult than steel TWBs. The current investigation focuses on an AA5182-O TWB made with dissimilar gauge materials joined by the gas tungsten arc welding process (GTAW). This paper discusses the material properties, the weld properties and microstructure, and the effect of weld orientation on formability as measured by the limiting dome height (LDH) test. The paper also presents some results of finite element modeling of the LDH forming test.