Analysis on Head Shedding off from Rivet of Turbine

A rivet head was found to have shed off from the turbine during the return check. Cracks were also found in the head R angles of some other rivets by means of fluorescence penetrant inspection. In this paper, the cause of rivet head shedding off from turbine was analyzed by means of fracture observation, hardness testing, chemical composition analysis and metallographic examination. The turbine structure and working condition were also considered. The results show that the fracture mode is fretting fatigue fracture. The turbine structure has obvious design deficiency:the riveted part is thin and its hardness is much higher than that of the rivet. The fretting fatigue fracture of rivet is related to design deficiency and material selection. Such measures as improving structure and selecting suitable rivet material can effectively prevent such failure.