Open AccessFailure analysis of cracking in aluminum alloy shell of a 220 kV gas insulated switchgear
Author(s) -
Baoshuai Du,
Zhongwen Zhang,
Sheng Su,
Xinmei Li,
Yanjiang Bu,
Liu Wen,
Dongting Wu
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/714/4/042003
Subject(s) - materials science , welding , residual stress , switchgear , alloy , cracking , metallurgy , leak , shell (structure) , microstructure , aluminium , stress (linguistics) , composite material , structural engineering , mechanical engineering , engineering , linguistics , philosophy , environmental engineering
Failure analysis of cracking of a GIS aluminum shell which causes SF6 gas leak in a 220 kV substation was present. Visual inspection, microstructure observation, chemical composition and mechanical properties characterization were performed to reveal the forming mechanism of the crack. It is found that the crack is located in the region of the aluminum alloy shell that undergone welding repair. The crack is continuous and develops within the weld metal. Detailed investigation reveals that the crack initiates by the defect of lack of fusion in the welding repaired zone. The working stress induced by gas pressure, combined with the residual stress and vibration stress, results in the extension of the crack and the final leaking of SF6 gas.