Fracture cause analysis of one tower bolt

doi:10.13251/j.issn.0254-6051.2025.02.050

Abstract

Abstract: One tower bolt used in one wind-power station was fractured. The fracture cause of the failed bolt was analyzed by means of metallographic examination, SEM-EDS analysis, chemical composition testing and mechanical property testing. The results show that chemical composition and mechanical properties all meet the requirements of national standard. There is no abnormality for the microstructure. But the R value at the connection between the head of the fractured bolt and the screw is too small. The depth of Zn-Ni plating near the crack source is deeper than other edges, which indicates that during quenching and tempering treatment, cracks are generated at the intersection of the bolt head and the screw under the action of quenching stress. When in use, under the action of force, cracks continue to propagate, ultimately leading to fatigue fracture.

Key words: tower bolt, fracture analysis, quenching crack

CLC Number:

TG115

Zhang Demei, Liang Xiaodong, Zhang Yan. Fracture cause analysis of one tower bolt[J]. Heat Treatment of Metals, 2025, 50(2): 312-315.

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