ZHANG Zhonghua, ZENG Fanyong, XIAO Zhiwei, et al.Microstructure and Mechanical Properties of T-joint of Embedded Parts by Continuous Drive Friction Welding[J].Electric Welding Machine, 2023, 53(1): 91-99.
ZHANG Zhonghua, ZENG Fanyong, XIAO Zhiwei, et al.Microstructure and Mechanical Properties of T-joint of Embedded Parts by Continuous Drive Friction Welding[J].Electric Welding Machine, 2023, 53(1): 91-99. DOI: 10.7512/j.issn.1001-2303.2023.01.14.
Microstructure and Mechanical Properties of T-joint of Embedded Parts by Continuous Drive Friction Welding
Continuous drive friction welding method was used for typical embedded steel bars in nuclear power plant, and the macroscopic morphology, microstructure and mechanical properties were analyzed. The results show that the upper and lower flying edges of the T-shaped friction welding joint are asymmetrically distributed due to the uneven heat dissipation during welding process, and the metal of the reinforcement side has obvious strain deformation during welding process. Through high magnification metallographic observation and scanning analysis, it is confirmed that the "black line" at the weld interface is normal metal organization rather than welding defect. Dynamic recrystallization occurrs in the weld nugget zone, which is fine ferrite and bainite, and carbides in the microstructure of the heat affected zone begin to precipitate after heating. The upset forging quantity can be used to measure the tensile quality of the joint. When the upset forging quantity of reinforcement exceeds a certain value, the tensile qualification rate of the joint can reach 100%. Through small-size tensile and hardness tests, it is found that the weakest area of friction weld joint is steel base metal, and the index affecting the fracture position of T-joint is seaming ratio, which is related to welding parameters (upset forging quantity) and pre-welding cleaning.
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