Article Significance of fracture toughness for linear friction welded joint of weathering steel

Kazuma Shimizu ORCID ; Shota Nakayama ; Hiroto Shoji ; Takumi Kawakubo ; Tomoya Nagira SAMURAI ORCID (National Institute for Materials Science) ; Mitsuru Ohata ; Hidetoshi Fujii

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Citation
Kazuma Shimizu, Shota Nakayama, Hiroto Shoji, Takumi Kawakubo, Tomoya Nagira, Mitsuru Ohata, Hidetoshi Fujii. Significance of fracture toughness for linear friction welded joint of weathering steel. Welding in the World. 2024, 69 (3), 739-750. https://doi.org/10.1007/s40194-024-01890-7

Description:

(abstract)

This paper examined the characteristics and the significance of fracture toughness for LFW (Linear Friction Welding) joints of weathering steel SPA-H processed under different joining conditions to control maximum temperature during LFW process. Two types of LFW joint were prepared; one was jointed under higher compressive pressure so as a maximum temperature during LFW process to be lower than the A1-transformation temperature (A1-LFW), and the other was jointed under lower compressive pressure to be higher than the A3-transformation temperature (A3-LFW). The fracture toughness of both joints where a crack was located at the joint interface exhibited higher value than that of the heat affected zone of CO2 gas-arc welds for the same steel. These results indicated that the LFW was more effective for the joining of weathering steel compared with a conventional arc-welding in terms of fracture toughness. However, A1-LFW exhibited lower fracture toughness (critical CTOD) than that of base metal or A3-LFW. Thus, the significance of the test results was discussed from mechanical and metallurgical viewpoints. The fracture toughness for A1-LFW found to be deteriorated due to work hardening associated with compressive plastic straining during LFW under higher compressive pressure, where the metal heated under A1-temperature was not completely ejected by friction but remined around the joint interface. On the other hand, the deterioration of fracture toughness for A3-LFW was found to be caused by hardening due to bainitic transformation near joint interface, whereas the narrowness of hardened region provided a little bit higher toughness than intrinsic toughness of the transformed phase due to plastic constraint loss.

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Keyword: Linear friction weld, Fracture toughness, Plastic constraint

Date published: 2024-12-26

Publisher: Springer Science and Business Media LLC

Journal:

  • Welding in the World (ISSN: 00432288) vol. 69 issue. 3 p. 739-750

Funding:

  • Iron and Steel Institute of Japan ISIJ Research Project
  • Osaka University

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1007/s40194-024-01890-7

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Updated at: 2025-03-03 16:30:48 +0900

Published on MDR: 2025-03-03 16:30:49 +0900

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