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There are abundant natural gas resources in western China, but many oil and gas fields are rich in chloridion, sulfureted hydrogen, carbon dioxide and other corrosive medium, which have strong corrosivity to pipeline. One gas field possesses abundant natural gas with great pressure, and the chloridion concentration in the water separated from gas is about 10%, so the medium has great corrosivity. In order to ensure the safety of the pipeline, about 13 km length pipeline and the internal pipes of a gas treatment plant that purifies gas about 12 billion cubic meter a year are made of 2205 duplex stainless steel (2205 DSS). 2205 DSS has many characteristics in welding with complex welding process; and because of high quality requirements for the construction of natural gas pipeline and restriction of on site conditions, the site welding is very difficult. Around the engineering application, a large number of experimental researches have been carried out on the material microstructure, properties and weldability. Finally welded joints which conform to the requirements of standard are obtained, contributing to the first large-scale application of this material in the field of oil and gas pipelines. Considering the engineering application and the latest research development, the welding and key factors affecting the joint properties of 2205 DSS pipes are summarized and analyzed. 相似文献
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采用Gleeble3500热-力学模拟试验机,对外径为φ1422 mm的X80管线钢焊接热影响区(HAZ)在不同冷却速度下的热循环过程进行了模拟,利用热膨胀法绘制模拟焊接热影响区连续冷却组织转变曲线(SH-CCT);结合光学显微组织和硬度测试等分析手段,研究了φ1422 mm的X80管线钢在不同冷却速度条件下焊接热影响区的组织变化规律。结果表明,冷却速度对X80管线钢的相变行为和微观结构具有显著影响。当冷却速度为1 ℃/s时,组织转变为贝氏体;当冷却速度达到7 ℃/s时,开始产生马氏体组织;当冷却速度为20 ℃/s时,组织内较高位错密度的板条贝氏体较多,组织晶粒较小。当冷却速度在7~20 ℃/s之间时,X80管线钢热影响区的显微硬度和冲击性能都大于母材。 相似文献
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Using ANSYS software, a finite element model for electron beam welding of 14.5 mm thick Ti-6Al-4V alloy plate is developed by a sequentially coupled thermal-mechanical analysis method. For the purpose of model validation, welding trial is carried out. Meanwhile, fusion zone dimensions and residual stresses are measured. The fusion-boundary profile is reproduced accurately by using a conical volume heat source model. The predicted residual stresses are in reasonable agreement with the results determined by the hole-drilling method. Through the analysis of predicted residual stresses, it is found that the normal residual stress in the interior of plate can not be negligible and the maximum value of three dimensional residual tensile stresses arises at 10.15 mm depth in the weld zone. 相似文献
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为解决阀门、仪表和法兰等安装过程中凸台焊机位置不当对HFW焊管整体性能影响的问题,研究了凸台直接焊接对HFW焊管原始残余应力、微观组织的影响。研究表明,HFW电阻焊管上整体残余应力值较小,直焊缝区域残余应力值低于管体区域;凸台焊接后,交叉焊缝附近直焊缝上的轴向和管体上环向残余应力值陡增了2.5和3.8倍,分别为444 MPa和433 MPa;凸台焊接对HFW焊管上表面的侵入宽度为15.167 mm,厚度为3.376 mm,侵入区域出现了链状贝氏体。综上所述,建议在凸台焊接时采用较小的焊接热输入。 相似文献
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12 mm厚钛合金平板电子束焊接的数值模拟 总被引:1,自引:0,他引:1
采用ANSYS有限元分析软件,建立12 mm厚TC4钛合金平板电子束焊接温度场和应力场的三维有限元数值计算模型。模型采用圆锥体热源考虑电子束焊接时的小孔效应;材料的热学、力学性能参数随温度变化;相变和熔池内液体的对流散热通过比热和热导率的变化实现。计算结果表明:钛合金电子束焊接时,熔池呈典型的卵形分布。高值纵向残余拉应力集中分布在焊缝中心线两侧距焊缝中心线4 mm的区域内,平板内部出现接近材料屈服极限的局部三维残余拉应力状态。实验得到的焊缝宏观形貌和小孔释放法检测到的焊接残余应力对计算结果进行验证,实验结果和计算结果吻合较好,证明了有限元模型的正确性。 相似文献
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利用热模拟技术模拟X100管线钢的焊接热过程,通过用光学显微镜、扫描电镜、透射电镜及显微硬度计对其显微组织观察及硬度测试,分析了其不同冷却速度下焊接热影响区(HAZ)的组织特征.结果表明,当冷却速度在0.05~5℃/s范围内时,HAZ显微组织主要以粒状贝氏体及块状铁素体为主,M/A岛主要以粒状或薄膜状存在;5℃/s时板条状贝氏体开始形成,M-A组元块状变大;冷速在15℃/s时,板条马氏体开始产生,板条贝氏体仍存在,边界处还有上贝氏体和下贝氏体存在;冷速在30~50℃/s时,显微组织主要以板条马氏体为主,M/A组元变大. 相似文献
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