Prediction of vulnerable zones based on residual stress and microstructure in CMT welded aluminum alloy joint
(1. Shandong Provincial Key Laboratory of Special Welding Technology, School of Materials Science and Engineering,
Harbin Institute of Technology at Weihai, Weihai 264209, China;
2. National Key Laboratory for Remanufacturing, Academy of Armored Forces Engineering, Beijing 100072, China;
3. Shanghai Key Laboratory of Materials Laser Processing and Modification,
Shanghai Jiao Tong University, Shanghai 200240, China)
Harbin Institute of Technology at Weihai, Weihai 264209, China;
2. National Key Laboratory for Remanufacturing, Academy of Armored Forces Engineering, Beijing 100072, China;
3. Shanghai Key Laboratory of Materials Laser Processing and Modification,
Shanghai Jiao Tong University, Shanghai 200240, China)
Abstract: Numerical simulation and experimental results were employed for the identification of the most vulnerable zones in three-pass cold-metal-transferring (CMT) welded joint. The residual stress distribution in the joint was predicted by finite element (FE) method, while the structural morphology of distinctive zones was obtained through metallographic experiments. The highest principal stress made the symmetric face of the joint most sensitive to tensile cracks under service conditions. Whereas, the boundaries between the weld seam and the base plates were sensitive to cracks because the equivalent von Mises stress was the highest when the first interpass cooling was finished. The third weld pass and the inter-pass remelted zones exhibited the modest mechanical performances as a result of the coarse grain and coarse grain boundary, respectively. The most vulnerable zones were regarded to be the crossed parts between the zones identified by numerical and experimental methods.
Key words: aluminum alloy; vulnerable zone; cold-metal-transferring welded joint; residual stress; microstructure morphology