输气管线在役焊接管道内壁变形的数值模拟

Numerical simulation on deformation in inner pipe wall of in-service welding onto gas pipeline

采用焊接过程数值模拟软件SYSWELD研究了输气管线在役焊接过程中管道内壁的变形,并和常规焊接进行了对比.结果表明,对于在役焊接近缝区的一点,随着焊接热源的靠近,变形量逐渐增大,当焊接热源经过该点时变形量最大,在随后的冷却过程中,变形量减小.在役焊接时焊接接头的变形与常规焊接有较大差异,在役焊接过程中接头的瞬态变形和残余变形均为外凸变形;而对于常规焊接,随着焊接冷却过程的进行,逐渐由外凸变形过渡为内凹变形,最终的残余变形为内凹变形.随着焊接热输入的增大,在役焊接接头近缝区的瞬态变形和残余变形均增大,远离焊缝中心区域的瞬态变形和残余变形随着热输入的增加而减小.

The software of SYSWELD was used to simulate the welding deformation in inner pipe wall when in-service welding onto active gas pipeline and the deference of welding deformation between in-service welding and routine welding was compared.The results show that,for a point in the region near the in-service welded seam,its deformation increases when the welding heat source closes up,and achieves maximum when the welding heat source passes through this point.The deformation decreases during the cooling process.The deformation of in-service welded joint has much difference with routine welded joint.The transient deformation and residual deformation of in-service welded joint are all convex deformation,but the transient deformation of routine welded joint changes from convex deformation to concave deformation during the cooling process and the residual deformation is concave deformation.When heat input is increased,the transient deformation and residual deformation in the region near the in-service welded seam are also increasing,but the transient deformation and residual deformation in the region far from the in-service welded seam are decreasing.