X80管道环缝焊接残余应力数值模拟

Numerical simulation of residual stress in circumferential weld of X80 pipeline

利用ABAQUS软件对直径1016 mm的X80天然气管道进行单层单道、4层4道与6层6道环缝的焊接模拟,研究管道的壁厚一定时,随焊接层数的变化,管道内、外表面轴向和环向焊接残余应力的变化趋势;随后对管道进行焊后热处理的模拟,考察经过热处理工艺后的残余应力变化规律。研究结果表明,当焊接层数增加时,环焊缝截面高应力区域的焊接残余应力大小整体下降;管道内、外表面的环向应力分布规律整体表现为由拉应力变为压应力,与4层、6层焊接不同,单层焊接管道外表面的轴向应力始终为压应力;热处理后,外表面的轴向应力峰值有较明显的减小作用,降低幅度为51.5%。内表面的环向应力峰值有较明显的减小作用,降低幅度为65.1%。

ABAQUS software was used to simulate the circumferential weld welding of X80 natural gas pipeline with a diameter of 1016 mm in1-layer-1-pass,4-layers-4-passes and 6-layers-6-passes.When the wall thickness of the pipeline was fixed,the variation trend of axial and circumferential welding residual stress on the inner and outer surfaces of the pipeline was studied with the change of the number of welding layers.Then,the post welding heat treatment of the pipeline was simulated to investigate the variation law of residual stress after heat treatment.The results showed that when the number of welding layers increased,the welding residual stress in the high stress area of circumferential weld section decreased as a whole.The circumferential stress distribution law on the inner and outer surfaces was changing from tensile stress to compressive stress as a whole.Being different from 4-layers and 6-layers welding,the axial stress on the outer surface of 1-layer welding pipe was always compressive stress.After heat treatment,the peak value of axial stress on the outer surface could be significantly reduced by51.5%.The peak value of circumferential stress on the inner surface could be significantly reduced by 65.1%.