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Effect of Local Postweld Heat Treatments on Metal Inert Gas-Welded A7N01S-T5 Joints

  • Pengcheng Zhao
  • Honglei Tang
  • Sen Lin
  • Lulu Wang
  • Jiajing PanEmail author
Article
  • 60 Downloads

Abstract

T6, T7, and retrogression and reaging (RRA) postweld heat treatments (PWHTs) were redefined and deployed to restore MIG-welded A7N01-T5 aluminum alloy joints in train-body structures using an inductive heating device. After the PWHT, the microstructures and mechanical properties of the joints were studied by x-ray diffraction (XRD), electron backscattered diffraction (EBSD), and scanning electron microscopy (SEM). The results showed that the hardness and strength of the joints were improved by the T6 treatment, and the tensile strength of the joints reached 87.39% of the base metal. However, an improvement in the corrosion resistance was not observed. The T7-treated joints enhanced the toughness of the welded joints and improved their corrosion resistance. The RRA-treated joints improved the toughness and corrosion resistance and increased the strength and hardness. The RRA treatment had a more comprehensive effect on the improvement of the welded joint structure and performance and is more suitable for postweld heat treatment of the aluminum alloy welded joints in the body of high-speed trains.

Keywords

A7N01S-T5 aluminum alloy MIG welding joint postweld heat treatment 

Notes

Acknowledgments

This work was supported by the Shandong Province Higher Educational Science and Technology Program (No. J12LA16), Shandong Natural Science Foundation (No. ZR2017PEE017) and Qingdao Applied Basic Research Program Youth Project (No. 17-1-1-16-jch).

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Copyright information

© ASM International 2019

Authors and Affiliations

  • Pengcheng Zhao
    • 1
  • Honglei Tang
    • 1
  • Sen Lin
    • 2
  • Lulu Wang
    • 1
  • Jiajing Pan
    • 1
    Email author
  1. 1.College of Electromechanical EngineeringQingdao University of Science and TechnologyQingdaoChina
  2. 2.School of Materials Science and EngineeringCentral South UniversityChangshaChina

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