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Numerical simulation and experimental verification of the restraint intensity of pipeline girth welding joint 下载免费PDF全文
The restraint intensity (RI) of the pipeline girth welding joint was investigated using finite element method and experimental method to predict the cold cracking susceptibility of pipeline steel. The distribution of RI along the girth weld was investigated to study the influence of welding position on the RI. Subsequently, the effects of outer diameter (OD) and wall thickness of pipeline on the RI were studied with ABAQUS software. The results show that the RI is almost independent of welding position. The RI increased with the increasing wall thickness but decreased with the increasing OD. A prediction model of RI was developed based on the effects of the OD and the wall thickness. It has been found that the predicted RIs were in good agreement with the experimental values. The maximum fractional error between the predicted RI and the experimental values was just about 10%. It was indicated that the errors were mainly caused by the heterogeneous of the weld bead. 相似文献
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对X70大管径管线钢焊接用自保护药芯焊丝进行研究.并进行焊接工艺和力学性能的评定,以确定其现场的焊接性,所有结果符合美国石油行业标准API1104《管道及有关设施的焊接》和一些附加的国内标准.结果表明,自制的自保护药芯焊丝有较好的全位置焊接性、良好的脱渣性和电弧稳定性,较低的飞溅率和发尘量.接头的抗拉强度为730~760MPa,-20℃冲击吸收功为125J.表明自制的自保护药芯焊丝能够在焊接X70管线钢时获得合格的接头.X70接头焊缝中微观组织有针状铁素体、块状铁素体、先共析铁素体和粒状贝氏体,在热影响区粗晶区没有发现魏氏组织.焊缝柱状晶区和HAZ粗晶区的主要组织是粒状贝氏体.在焊接接头中获得贝氏体组织,使这种自制自保护药芯焊丝能够符合规定的力学性能的要求. 相似文献
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焊接新技术在我国管道建设中的应用 总被引:2,自引:0,他引:2
探讨了高强度管线钢管焊接施工所面临的难点,分析了我国管道建设目前常用的两种焊接工艺的优势与局限性,论述了西气东输二线X80管道建设中应用的焊接新技术。提出了研发高质量的焊接材料和与之相匹配的高效率焊接方法,对保证环焊接头的强韧性,提高现场焊接施工效率具有十分重大的意义,并认为数字电源、气保护药芯焊丝、金属粉芯焊丝、双焊炬自动焊等焊接新技术的成功应用,将把我国管道焊接施工技术推进到一个新的阶段。 相似文献
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X80管线钢焊接粗晶区的组织和性能 总被引:3,自引:0,他引:3
采用热模拟技术研究了X80管线钢粗晶区组织和低温韧性的变化规律,讨论了冷却时间、组织和性能之间的关系。结果表明,焊接粗晶区主要由板条束状贝氏体和粒状贝氏体组成。当t8/5在6~8s时,粒状贝氏体含量较多,其分割作用使板条贝氏体的方向性减弱,使板条更为细小;M-A组元呈块状,尺寸较小且均匀分布在基体上,冲击韧度最优越;当t8/5增大或减小时,板条束状贝氏体的含量均增加,板条粗大,M-A组元在冷却速度较快时呈长条状,冷却速度较慢时呈块状且相对含量增加,尺寸增大,均使冲击韧度显著下降。 相似文献