【作者】 刘俊龑；

【导师】 霍立兴；

【作者基本信息】 天津大学 ， 材料加工工程， 2004， 硕士

【摘要】 海底管线作为一种工程结构,在实际中有着广泛而重要的应用,担负着输送诸如石油、天然气等介质的重要任务。同时,作为一种焊接结构,管线的焊接接头也不可避免的会存在各种可能的焊接缺陷。随着工程实际应用的发展,人们逐渐以“合于使用”的思想原则来对焊接缺陷可能给结构带来的影响进行合理的评价,而不再采用以往使用的“完美无缺”的经验方法来要求结构中不能存在任何的焊接缺陷。这不仅将结构的经济性纳入考虑的范围,而且为评定结构安全运行提供了坚实的理论基础和实验验证。本文以“合于使用”的思想为原则,依据在国际上广泛使用的标准BS7910,对中国海洋石油总公司渤海石油公司(COOEC)所开发的旅顺至大连间海底石油传输管线X56海底管线进行ECA(EngineeringCritical Assessment)评估。在此过程中,我们首先对BS7910:1999标准进行了解和掌握,并自主开发断裂评定软件。为了获得进行ECA评估所需的管道材料的性能数值,我们以对管道供应商提供的数据进行分析的方式获得母材金属的拉伸力学性能; 通过对焊缝金属进行力学性能实验的方式获得其力学性能,并通过测定CTOD-R阻力曲线确定热影响区和焊缝金属分别具有的断裂韧性。在完成上述任务的基础上,本文依据BS7910标准的规定,对处于不同位置处的不同类型裂纹进行相应级别的评定,通过迭代计算,得到在铺设过程中可以接受的焊接裂纹的极限和允许尺寸,为在铺设过程中进行的无损检测提供缺陷验收的依据。更多还原

【Abstract】 As a kind of engineering structure, the submarineline has the abroadand important applications, which always is used to deliver the oil and thegas. At the same time, as a kind of welded structure, the welded joint ofthe pipeline always has the inevitable welding defects.With the development of the engineering practice, people graduallyuse the principle of the “fitness for use” to assess the influence of thewelding defects on the structures, and don’t required that the structureshould not contain any welding defects. This movement not only take intoaccount of the economic cost of the structure, but also provide the stabletheoretical basis and experimental verification for the safe performanceof the structure.This paper uses the principle of the “fitness for use” and theregulation of the BS7910:1999 to make an engineering critical assessment(ECA) for the submarineline which is developed by the COOEC and islocated between Lvshun and Dalian.To finish the assessment, at first, we understand the regulations andthe theories of the BS7910 and make the assessment software. Then, weobtain the tensile property of the X56 pipe by the analysis of the tensileand yield strength value which is obtained from the mill certificates,obtain the tensile property of the weld by performing the tensile testing ofthe weld metal and obtain the fracture toughness of the HAZ and the weldmetal by determining the CTOD-R cure of them. After that, we performthe relevant assessment to determine the critical/tolerable size of thedifferent kind of flaws and the flaws located in the different zones of thejoint. The assessment results are obtained by the iterated calculation andare calculated for the laying condition and for “as laid” condition prior totrenching and burying, which offer the basis for the check and accept ofthe welding defect when the joint is detected by the NDT.更多还原