基于SYSWELD的在役焊接径向变形数值模拟

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

采用焊接模拟软件SYSWELD研究壁厚、管径及熔池尺寸等因素对天然气管道在役焊接径向变形的影响.结果表明：发生烧穿的临界瞬时最大变形有时间效应;发生临界变形的时间随着壁厚的增大而增加,径向变形量减小;随着管径增加,径向变形量在同壁厚下逐渐增大;壁厚为4.5 mm时,小管径管道易达到临界变形量;壁厚为6 mm时,管径的增大降低了临界变形发生的可能性;当壁厚为7.5 mm,管径由254 mm增大到508 mm时,发生临界变形的可能性减小,而管径在508～ 1016 mm时,管径的增大增加了临界变形发生的可能性;内壁点的径向变形随着热源的靠近而增大,随着壁厚的增大而减小,但当壁厚增大到6 mm后,壁厚的增大对其不再有显著影响;熔池尺寸影响焊接修复同时刻时的径向变形量,达到临界变形量的时间与熔池尺寸成反比,表现出明显的熔池尺寸效应.

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 4.5 mm,the smaller the pipe diameter is,the more easily the critical deformation is reached; when the wall thickness is 6 mm,the increase of pipe diameter will reduce the generation rate of critical deformation; when the wall thickness is 7.5 mm,the generation rate of critical deformation decreases with the increase of diameter from 254 mm to 508 mm,and at a pipe diameter range from 508 mm to 1016 mm,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 6 mm,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.