Effect of groove on socket welds under the condition of vibration fatigue

• Published in: Journal of nuclear materials Vol. 433; no. 1-3; pp. 10 - 16
• Main Authors: Xiu, Junjie, Jing, Hongyang, Han, Yongdian, Zhao, Lei, Xu, Lianyong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2013; Elsevier
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; Finite element method; Fatigue test; Vibration; Stress distribution; Piping; Nuclear power plant; Fatigue strength; Palladium; Nuclear reactor; Weld
• DOI: 10.1016/j.jnucmat.2012.08.051
• ISSN: 0022-3115

Root failures of socket welds in small bore piping caused by vibration mainly occur at nuclear power plants (NPPs). It was observed that at higher stress level failures tended to originate at the toe while for the case of lower stress failures tended to occur at the root. The groove can increase the penetration depth (PD) of root, which is beneficial to the fatigue life. The effect of groove was also investigated by finite element method (FEM). The simulation results show that groove can decline the stress distribution, stress triaxiality and maximum principal plastic strain in the weld root, and the 5mm groove suffering σmax (the highest stress of root failure) is almost same as no groove subjecting to σf (fatigue limit). The test results show that the socket weld with groove can increase the natural frequency and damping of specimen, which make the system more difficult to vibrate. Moreover, the groove can also improve the fatigue property of specimen which do not exist the root failure even under high cycle fatigue (HCF).