Numerical study of fillet weld leg height of sleeve repair welding for in-service pipeline

This paper presents a mechanical calculation and numerical simulation of the fillet weld of sleeve repair. The mechanical analysis based on the yield criteria is performed to obtain the minimum value of the fillet weld leg height to ensure the strength and load-bearing capacity of the weld. Within the framework of numerical simulation, the parameters of double ellipsoid heat source are determined by fitting method and the simulated molten pool morphology agrees well with the practical weld. Finite element models with various weld leg height are performed to predict the distribution and magnitude of the deformation and stress. The simulation takes into account thermal, metallurgical and mechanical factors, and the maximum value of the fillet weld leg height is obtained based on the magnitude of the deformation and stress. The mechanical calculation and numerical simulation results show that 1.2-2 times wall thickness is an optimal range of fillet weld leg height. And reasonable parameters of sleeve repair for in-service welding are provided for engineering field, which can improve the service life of the weld and production efficiency.