Welding in the World

, Volume 62, Issue 4, pp 721–727 | Cite as

Microstructures and their distribution within HAZ of X80 pipeline steel welded using hybrid laser-MIG welding

  • Limeng Yin
  • Jinzhao Wang
  • Xizhang Chen
  • Cheng Liu
  • Arshad Noor Siddiquee
  • Gang Wang
  • Zongxiang Yao
Research Paper


Large microstructure gradient in the heat-affected zone (HAZ) in the joints of large thick material welded by the hybrid laser-MIG welding technology reduces the in-service reliability and durability of the welded structure. It is of great importance to characterize and analyze how the microstructure distribution and evolution occur in the HAZ of the laser-MIG hybrid welded joints fabricated with X80 pipeline steel. In this article, the HAZ is found to comprise these characteristic zones, namely banded microstructure HAZ (BMHAZ), fine-grained HAZ (FGHAZ), transitional microstructure HAZ (TMHAZ), and coarse-grained HAZ (CGHAZ). The zone of the HAZ contains quasi-polygonal ferrite (QF), M-A component, polygonal ferrite (PF), and bainite ferrite (BF). From the base metal side towards the weld center with the decrease in the distance, the size of the M-A components decreases and its distribution is more dispersed, while the content of QF decreases in the HAZ. The average diameter of the original austenite grain increases gradually and so does the content of lath microstructures.


Laser-MIG hybrid welding X80 pipeline steel Microstructure HAZ 


Funding information

This research was supported by National Natural Science Foundation of China (No. 51674056 and 51575401), the Scientific and Technological Research Program of Chongqing Municipal Education Commission (No. KJ1713344), the State Key Lab of Advanced Welding and Joining at Harbin Institute of Technology (No. AWJ-M15-05), and the Opening Project of Materials Corrosion and Protection Key Laboratory of Sichuan Province (No. 2016CL15).


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Copyright information

© International Institute of Welding 2018

Authors and Affiliations

  • Limeng Yin
    • 1
    • 2
  • Jinzhao Wang
    • 1
  • Xizhang Chen
    • 3
  • Cheng Liu
    • 1
  • Arshad Noor Siddiquee
    • 4
  • Gang Wang
    • 1
  • Zongxiang Yao
    • 1
  1. 1.School of Metallurgy and Materials EngineeringChongqing University of Science and TechnologyChongqingChina
  2. 2.State Key Laboratory of Advanced Welding and JoiningHarbin Institute of TechnologyHarbinChina
  3. 3.School of Electrical and Mechanical EngineeringWenzhou UniversityWenzhouChina
  4. 4.Department of Mechanical EngineeringJamia Millia Islamia (A Central University)New DelhiIndia

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