基于SYSWELD的运行管道在役焊接热循环数值模拟

采用焊接过程数值模拟软件SYSWELD建立模型,以水为运行介质,对X70管道在役焊接粗晶区的热循环进行了数值模拟,探讨了介质流速、管道壁厚和焊接热输入等因素对在役焊接热循环的影响规律,并对数值模拟结果进行了验证.结果表明,在役焊接粗晶区t8/5值随着水流速度的增大而减小,但减小的幅度不大;当流速小于0.5 m/s时,t8/3和t8/1随流速的增大而大幅减小,当流速大于0.5 m/s时,t8/3和t8/1随流速增大而缓慢减小.t8/5和t8/3均随着管道壁厚的增加而先增大后减小,在壁厚为8 mm时达到最大值;t8/1随着壁厚的增加而逐渐增大.随着焊接热输入的增加,t8/5,t8/3和t8/1均增大.焊接热循环计算结果和实测结果吻合较好,相对误差小于8%.

Numerical simulation of thermal cycle of in-service welding onto active pipeline based on SYSWELD

The software of SYSWELD was used to build model and simulate the thermal cycle of in-service welding onto active pipeline of X70 steel using water as flowing medium.Influence of flow rate,pipe wall thickness and heat input on thermal cycle of coarse grain heat-affected zone was studied and the simulation results were tested by measuring thermal cycle on experiment pipelines.The results show that t_(8/5) decreases when flow rate increases but the decrease amplitude is not so obvious.When flow rate is less than 0.5 m/s,t_(8/3) and t_(8/1) rapidly decrease while flow rate increases.When flow rate is greater than 0.5 m/s,t_(8/3) and t_(8/1) decrease slowly while the flow rate increases.t_(8/5) and t_(8/3) increase with the pipe wall thickness increasing and arrive at the maximum when wall thickness is 8 mm,and then decreases.But t_(8/1) increases when wall thickness increases from 5 mm to 12 mm.t_(8/5),t_(8/3) and t_(8/1) increase with heat input increasing.The simulation results of the thermal cycle agree well with the measured results and the relative error is less than 8%.