Numerical Simulations of temperature for the in-service welding of gas pipeline

Finite element (FE) method is employed to simulate the temperature field of the in-service welding on a single bead-on-pipeline. The methane gas was introduced as a cooling media to investigate the temperature field of the heat affected zone (HAZ) based on the validation of the numerical models. The heat transfer coefficient is significantly influenced by the pressure and flow rate of the gas and wall thickness of pipeline, which leads to the magnitude of cooling time, horizontal and vertical sizes of HAZ and peak temperature at inner wall were reduced. While, the t8/1 increases first and then decreases with the variable wall thickness and it get the maximum value about 208.42 s at wall thickness of 8 mm. It indicates that the effect of the gas and wall thickness on the temperature field of in-service welding need to be concerned.