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X80管线钢焊接接头SSCC研究及数值模拟

SSCC of welded joint for X80 pipeline steel and numerical simulation

  • 摘要: 硫化氢应力腐蚀破裂(sulfide stress corrosion cracking,SSCC)是制约管线钢应用的主要因素。针对X80管线钢焊接接头进行恒位移硫化氢应力腐蚀试验研究,分别测得母材、焊缝和热影响区的应力强度因子门槛值KISCC和裂纹扩展速率da/dt。通过对X80管线钢焊接接头的金相显微组织、断口形貌观察以及硬度测试,分析了X80管线钢SSCC性能的影响因素。并对WOL试样进行了三维弹塑性有限元分析,得到裂纹尖端应力场分布和氢浓度的分布特征。结果表明,热影响区的KISCC最小,裂纹扩展速率最大,具有较差的抗应力腐蚀开裂的能力,其应力腐蚀试验结果与有限元数值分析相互验证。

     

    Abstract: Sulfide hydrogen stress corrosion cracking (SSCC) is the main factor to restrain the application of the pipeline steels. The critical stress intensity factor KISCC and crack propagation rate d a d t of base metal, weld and heat affected zone were obtained by the Wedge-open loading constant displacement specimens, based on the H2S stress corrosion test for X80 pipeline steel.The factors affecting the performance of SSCC were analyzed through the microstructure, fracture pattern and hardness testing of the joints of X80 pipeline steel.By the analysis of the three-dimensional elastic-plastic finite element model of WOL sample, the stress field and hydrogen concentration distribution property of the crack tip were obtained.The heat affected zone showed minimum KISCC, maximum crack propagation rate and poor property of resisting stress corrosion cracking.The result of stress corrosion testing and the result of finite element numerical analysis verified each other.

     

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