Advances in Manufacturing ›› 2025, Vol. 13 ›› Issue (4): 737-749.doi: 10.1007/s40436-025-00547-y

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Enhanced low-temperature toughness of laser-arc hybrid welding of Q450NQR1 high-strength weathering steel via beam oscillation

Meng-Cheng Gong1,2, Yu-Chun Deng1, Zhao-Yang Wang1, Shuai Zhang1, Da-Feng Wang3, Ming Gao1   

  1. 1. Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China;
    2. Optics Valley Laboratory (OVL), Wuhan, 430074, People's Republic of China;
    3. Ningbo Branch of Chinese Academy of Ordnance Science, Ningbo, 315103, Zhejiang, People's Republic of China
  • Received:2023-11-14 Revised:2024-03-14 Published:2025-12-06
  • Contact: Ming Gao Email:E-mail:mgao@mail.hust.edu.cn E-mail:mgao@mail.hust.edu.cn
  • Supported by:
    This research was financially supported by the National Natural Science Foundation of China (Grant No. 52275335) and the Postdoctoral Fellowship Program of the CPSF (Grant No. GZB20230231, and the Postdoctoral Science Foundation of China (Grant Nos. 2023M731173 and 2023M731194).

Abstract: Suppressed low-temperature toughness mismatch between the fusion zone (FZ) and base metal (BM) was achieved in a Q450NQR1 high-strength weathering steel joint by employing laser-arc hybrid welding (LAHW) with beam oscillation (O-LAHW), thereby avoiding the heat aggregation of conventional LAHW at the center of the molten pool. The O-LAHWed joint exhibited a higher content of acicular ferrite in the FZ, increasing it by 8% compared with the LAHWed joint, reaching the maximum value of 61%. Meanwhile, the O-LAHWed joint demonstrates higher ultimate tensile strength (775 MPa), yield strength (697 MPa), and impact absorption energy (175 J for FZ, at -40 °C) compared to LAHWed joints, with increases of 3%, 9%, and 35%, respectively. That is, O-LAHW can significantly improve the impact toughness at low temperatures and exhibit a low-temperature toughness matching degree of 118% with BM, surpassing the metal active-gas arc-welded joints reported in the existing literature by more than one time. The key factor contributing to the improved low-temperature toughness of the FZ was the interlocked microstructure with a high dislocation density promoted by the beam stirring effect.

The full text can be downloaded at https://doi.org/10.1007/s40436-025-00547-y

Key words: Weathering steel, Laser-arc hybrid welding (LAHW), Laser beam oscillation, Microstructure, Low-temperature impact toughness