Formability of friction-stir-welded dissimilar-aluminum-alloy sheets
- PDF / 377,157 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 101 Downloads / 274 Views
I. INTRODUCTION
STAMPED metal parts are used widely in many industries, including automotive, appliance, and aerospace, in addition to having myriad smaller manufacturing applications. In some cases, the blanks used as starting material can be tailored in thickness to optimize weight. This tailoring has typically been done by welding sheets of differing thicknesses together, in a manner that allocates an appropriate amount of material to two or more separate areas, taking into account engineering and dimensional requirements. The blank is then stretch formed and drawn, resulting in a part with optimized weight. More recently, attempts have been made to weld dissimilar-aluminum alloys together, which ultimately could provide flexibility to designers who are trying to optimize strength, weight, and corrosion resistance.[1,2,3] Different welding techniques have been used to make tailored blanks. For aluminum alloys, laser welding, nonvacuum-electron-beam (NVEB) welding, or gas-tungsten-arc welding (GTAW) are used, because the high electrical and thermal conductivity of aluminum make mash-seam welding unsuitable.[4–7] One of the challenges in welding a tailored blank, as opposed to other situations in which a weld is a structural joint for a static member, is the forming process to which the weld is subjected. Tailored blanks for automotive stampings are typically stretch formed and drawn, resulting in large and complex strains in both the parent and weld material. Mechanical testing can be done to measure weld formability relative to the formability of the parent material, using both tension and various formability tests. A recent study was done to investigate the feasibility of joining dissimilar alloys via fusion welding using GTAW[1] as a welding process, while employing a special test (SigM.P. MILES, Assistant Professor, Manufacturing Engineering Technology, and T.W. NELSON, Associate Professor, Mechanical Engineering, are with the College of Engineering and Technology, Brigham Young University, Provo, UT 84602. Contact e-mail: [email protected] D.W. MELTON, formerly Graduate Student, Manufacturing Engineering Technology, Brigham Young University, is Doctoral Candidate, Utah State University, Logan, UT 84322. Manuscript submitted July 9, 2004. METALLURGICAL AND MATERIALS TRANSACTIONS A
majig test) to evaluate the cracking susceptibility of various dissimilar combinations of 5182-H16, 5754-O, 6022T4, and 6111-T4. The results of this work showed that cracking resistance during welding was highest for the 5182/5754 alloy pair, while combinations of 6022 with either 5754 or 5182 resulted in the lowest cracking resistance. Work has also been done on friction stir welding (FSW) of a cast A356 aluminum alloy to a wrought 6061 aluminum alloy.[3] The results from this study showed that good, defectfree welds were produced using FSW, but that the transverse tensile ductility of the welded materials was governed by the weaker alloy, which in this case was the A356. The difficulties that have been observed in obtaining good me
Data Loading...
