Numerical simulation of radial deformation during in-service welding based on SYSWELD

Key words:  in-service welding  gas pipeline  radial deformation  numerical simulation

Abstract:

The welding software of SYSWELD was used to simulate the effects of wall thickness, pipe diameter and the pool size on the radial direction deformation during the in-service welding of pipeline. The results show that:the critical instantaneous maximum deformation, which will result in burn through pipeline, has time effect; the time reaching critical deformation increases with the increase of wall thickness, at some time, the deformation amount reduced. With the increase of pipe diameter, the radial direction deformation will increase at the same wall thickness; when the wall thickness is 4.5mm, the smaller the pipe diameter is, the more easily the critical deformation is reached; when the wall thickness is 6mm, the increase of pipe diameter will reduce the generation rate of critical deformation; when the wall thickness is 7.5mm, the generation rate of critical deformation decreases with the increase of diameter from 254mm to 508mm, and at a pipe diameter range from 508mm to 1016mm, the generation rate increases with the increase of pipe diameter. The radial direction deformation of inner wall increases when the heat source is closer, and it reduces with the increase of wall thickness. And when the wall thickness is greater than 6mm, the wall thickness no longer has significant effect on the radial direction deformation. The size of pool affects the radial direction deformation of weld repair, and the time reaching critical deformation reduces with the increase of pool size, which shows significant pool size effects.