摘要
基于有限元分析软件ANSYS,对SA335 P91炉管全位置对接打底焊温度场和应力一应变场进行了三维数值模拟。建立了焊接瞬态温度场和应力一应变场三维移动热源模型,得到了全位置焊时左右焊道交汇处(90°)的瞬态轴向应力和环向应力分布以及应力-应变随时间变化的规律:在闭合小孔区内表面的轴向和环向应力均为拉伸应力,且环向应力比轴向应力大,并有明显的边缘应力效应;该处在高温凝固阶段的瞬态应力随小孔停留时间的延长和焊接电流的增大而减小。与之相反,其等效应变的变化则随之增大,这是造成打底焊时在小孔闭合区容易产生凝固裂纹的主要原因之一。
Based on ANSYS,three-dimensional finite element numerical simulation of all-position root weiding in girth welded SA335 P91 steel pipe is carried out.Three-dimensional FEM using mobile heat source for analysis of transient temperature field and welding stress strain field in butt weld roots joint of pipe is founded.Distribution of axial and hoop transient stress- es in the conjunction of two half seams is investigated. The axial and hoop stresses at the keyhole center are tensile,especially the edge stress effect is remarkable round the keyhole where the hoop stress is bigger than the axial stress.The calculation results show that the transient stress produced by high temperature solidifica- tion decreases with the prolongation of holing time and the increase of welding current,which is a significant factor in solidification cracking cases.
出处
《乙烯工业》
CAS
2007年第4期31-37,共7页
Ethylene Industry
