Crack failure analysis of a temperature transmitter sleeving of a gas transmission station

Abstract

Based on the exterior morphology, fracture morphology and metallographic analysis and energy dispersive spectroscopy analysis, the causes of cracking of a temperature transmitter sleeving tube of a gas station are analyzed, the results showing that the main cause of the sleeving crack was the raw material of sleeving has not been treated with solid solution annealing or the heat treatment was not completely processed. therefore, the lack of treatment makes the material gathered a large number of Cr carbides on grain boundary, this leaded to the low anti intergranular corrosion ability; The thread in the sleeving does not meet the requirements of thread processing specifications, which caused the thread near the port to be squeezed in the service process of the sleeving, resulting in large tensile stress at the outer port of the sleeving. In the case of stress concentration caused by mechanical damage at the port position and the corrosion environment, stress corrosion cracking occurred at the port mechanical damage position and eventually lead to leakage.