板式换热器管板接头补焊残余应力数值模拟

Numerical simulation of repairing weld residual stress for tube-sheet joint in plate heat exchanger

板式换热器管板接头处存在大量的焊接残余应力,会引起应力腐蚀开裂,产生泄露现象。利用有限元软件ABAQUS对管板接头补焊残余应力进行数值模拟,从残余应力的角度优化管板补焊接头坡口形状。计算结果表明,在管板焊接接头焊缝和热影响区产生了较大的残余应力,环形应力最大,径向应力次之,轴向应力最小,最大残余应力值产生在焊缝与母材交界处。与L形和V形坡口相比,U形坡口焊接接头的残余应力较小。与单边U形坡口相比,双边U形坡口能够降低焊接残余应力,有利于降低应力腐蚀开裂的敏感性。双边U形坡口是一种最佳补焊坡口形式,为工程上管板式换热器焊接接头补焊工艺提供参考。

A large number of welding residual stresses were generated in the tube-sheet joint of plate heat exchanger,and it have a great influence on stress corrosion cracking and may leads to leakage. In this paper,the finite element software ABAQUS was used to simulate the weld residual stress, and the weld groove shape was also optimized to reduce residual stress. The calculated results show that the lager residual stress was generated in the weld and heat affected zone of tube sheet joint. The hoop stress is largest, and then the radial stress,and the axial stress is smallest. The maximum residual stress was generated in the weld metal adjacent to parent metal. Compared with the L shaped and V shaped groove weld joint,the residual stress in U groove welded joints is smallest. Compared with the bilateral U groove,the unilateral U groove can reduce the welding residual stress and will help to reduce the sensitivity of stress corrosion cracking. The bilateral U groove is one of the best groove form for repairing weld, and this provide a reference for engineering welding process for plate heat exchanger joints.