As an important equipment for purifying crude oil and natural gas in energy industry, absorber is subjected to harsh working environment of high stress and severe corrosion. Especially, weld is the weak region of the absorber, which faces significant risk of crack propagation due to residual stress caused by the welding process, working pressure and temperature. Meanwhile, crack propagation in absorbers with high pressure, high temperature and toxic media can often cause disastrous consequences. Therefore, to solve this problem, a systematic method considering welding, heat treatment and working process is presented in this paper to predict crack propagation completely in the weld. In the case, based on actual conditions, a finite element model (FEM) of welding process considering transient heat transfer and heat radiation for residual stress field analysis is established to obtain the far-field stress for cracks. Then, the detailed analysis of stress field and stress intensity factor () under the obtained far-field stress at the crack tip is carried out through the method of integrating the strain energy density (SED) in the crack tip region. Finally, experiments of fracture toughness () of undamaged weld specimens and post-corrosion weld samples are carried out to compare with obtained by FEM and evaluate the safety of existing cracks. The method presented in this paper is a complete system that can provide a universal technological basis for crack propagation prediction and safety assessment of pressure vessel.

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吸波器焊缝裂纹扩展预测方法的实验与模拟研究

吸收塔作为能源工业中净化原油、天然气的重要设备，承受着高应力、严重腐蚀的恶劣工作环境。特别是焊缝是吸波器的薄弱区域，由于焊接工艺、工作压力和温度产生的残余应力，焊缝面临着裂纹扩展的巨大风险。同时，高压、高温和有毒介质下的吸收器裂纹扩展往往会造成灾难性的后果。因此，为了解决这一问题，本文提出了一种考虑焊接、热处理和加工工艺的系统方法，以完全预测焊缝中的裂纹扩展。本案例中，根据实际情况，建立了考虑瞬态传热和热辐射的焊接过程有限元模型（FEM），进行残余应力场分析，获得裂纹的远场应力。然后，通过对裂纹尖端区域应变能密度（SED）进行积分的方法，对获得的裂纹尖端远场应力下的应力场和应力强度因子（）进行详细分析。最后，对未损伤焊缝试样和腐蚀后焊缝试样进行断裂韧性实验，与有限元法得到的结果进行比较，评价现有裂纹的安全性。本文提出的方法是一个完整的体系，可以为压力容器裂纹扩展预测和安全评估提供通用的技术基础。