Affiliation:
1. Department of Mechanical Engineering, Incheon National University, Incheon 22012, Republic of Korea
2. R&D Division, Hyundai Motor Company, Seoul 06797, Republic of Korea
Abstract
This study presents information on the behavior of paint baking (PB) after resistance spot welding of the 5- and 6xxx series aluminum alloys. The weld parameters are optimized, and the weld specimens are baked three times for 20 min at 180 °C to simulate the heat treatments required for paint baking. The mechanical properties of the samples were characterized by using the lap shear test, micro/nanoindentation hardness, and fatigue test. As the mechanical properties of the weld are affected by the characteristics of the heat-affected zone and those of the fusion zone, the microstructure of the cross-sections was also analyzed through optical and electron microscopy. The investigation of the 6xxx series welds showed that the post-processing heat treatment decreased both the strength and the toughness of the weld, which resulted from the reduced hardness of the microstructure. Additionally, the lap shear test indicated that the failure mode for the 6xxx series changed from nugget failure to partial nugget failure after the paint baking process. However, the mechanical properties of the 5xxx welds were not affected as much as the 6xxx series during baking heat treatment. The fatigue test for the 6xxx series showed a different tendency from the lap shear test. Its fatigue properties improved due to an increased elastic modulus after the heat treatment.
Funder
Incheon National University
Subject
General Materials Science,Metals and Alloys
Reference35 articles.
1. Joining aluminum sheet in the automotive industry—A 30 year history;Gould;Weld. J.,2012
2. Gullino, A., Matteis, P., and D’Aiuto, F. (2019). Review of aluminum-to-steel welding technologies for car-body applications. Metals, 9.
3. Loganathan, K., and Subramani, S.K.V.S. (2023). Materials Today Proceedings, Elsevier.
4. Recent development in aluminium alloys for the automotive industry;Miller;Mater. Sci. Eng. A,2000
5. Resistance spot weldability of heat-treatable and non-heat-treatable dissimilar aluminium alloys;Lee;Sci. Technol. Weld. Join.,2020