Kazuma Shimizu
;
Shota Nakayama
;
Hiroto Shoji
;
Takumi Kawakubo
;
Tomoya Nagira
(National Institute for Materials Science)
;
Mitsuru Ohata
;
Hidetoshi Fujii
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.
Rights:
Keyword: Linear friction weld, Fracture toughness, Plastic constraint
Date published: 2024-12-26
Publisher: Springer Science and Business Media LLC
Journal:
Funding:
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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