High-grade(API 5L X80)and large-diameter(OD 1422 mm)line pipes are used in the Sino-Russian eastern route gas pipeline project for high pressure(12 MPa)transmission,and this can significantly increase the transmission...High-grade(API 5L X80)and large-diameter(OD 1422 mm)line pipes are used in the Sino-Russian eastern route gas pipeline project for high pressure(12 MPa)transmission,and this can significantly increase the transmission capacity and meet China's energy strategic demand.With the increase of steel grade,transmission pressure,pipe diameter and design coefficient,however,ductile crack of line pipes becomes the dominant crack mode,so it is necessary to focus on crack arrest and control study.In this paper,therefore,an intensive study was performed on the Battelle Two-Curve(BTC)method which is the major solution to the calculation of arrest toughness,as well as the crack resistance curve and decompression curve.Based on the study,the principle and application range of the BTC method were confirmed.In addition,a series of analysis were conducted on the issues which occurred when the BTC method was applied to high-strength,high-toughness line pipe steel,and the commonly used modified approaches to BTC calculation results were also provided.After the crack control scheme of the X80 large OD 1422 mm line pipes for the Russian Bovanenkovo-Ukhta was reviewed,the BTC calculation results were corrected on the basis of the design parameters of the Sino-Russian eastern routine gas pipeline project,the Charpy V-notched(CVN)impact energy which meets the project requirement was finally worked out to be 245 J.展开更多
陶瓷-纤维复合靶板是当前轻型防护工程中常用的装甲结构。对于复合装甲的弹道性能国内外学者已经进行了大量的研究,然而对于硬质弹芯和陶瓷-纤维复合靶板作用过程中的破碎特征研究相对较少。弹芯和陶瓷材料的破碎情况对整体复合装甲的...陶瓷-纤维复合靶板是当前轻型防护工程中常用的装甲结构。对于复合装甲的弹道性能国内外学者已经进行了大量的研究,然而对于硬质弹芯和陶瓷-纤维复合靶板作用过程中的破碎特征研究相对较少。弹芯和陶瓷材料的破碎情况对整体复合装甲的防护性能存在较明显的相关性。本文利用12.7 mm的穿甲燃烧弹正侵彻SiC陶瓷-纤维复合靶板,在保证复合靶板面密度相近的情况下,设计了3种不同厚度比的Kevlar/SiC-碳纤维增强环氧树脂基复合材料(T300)-超高分子量聚乙烯(UHMWPE)复合靶板。通过观察回收的弹芯和陶瓷-纤维复合靶板的整体破坏形貌,分析了弹芯和纤维层合板的主要损伤模式。同时对回收的弹芯和陶瓷碎块进行多级筛分称重处理,得到了复合靶板在不同厚度比下弹芯和陶瓷的碎块质量分布符合幂律分布规律。实验结果表明:9 mm SiC+4 mm T300+10 mm UHMWPE的厚度组合在3种不同厚度比中的抗侵彻性能最优,将1 mm厚的SiC陶瓷替换成1 mm厚的碳纤维T300在降低质量的同时可以提高复合装甲的防护能力。复合靶板的失效破坏模式包括陶瓷在高速冲击下形成陶瓷锥和径向裂纹。UHMWPE层合板由拉伸波造成的层间分离现象,背部凸起永久塑性变形及主要为剪切力导致穿孔失效。碳纤维T300层合板损伤形式主要是剪切力导致的十字型脆性断裂,同时伴随冲塞碎块的脱落。弹芯头部主要呈现粉碎性磨蚀破碎,对于较大的弹芯碎块主要是由剪切应力和拉伸应力共同作用下的拉剪失效断裂。陶瓷-纤维复合装甲理想模型是在陶瓷后加入较高刚度的弹性材料同时背板应选择具有高抗拉强度及良好冲击韧性的材料。展开更多
文摘为了满足中俄东线天然气管道工程380×10~8 m^3/a超大输气量的要求,大口径、厚壁、高钢级钢管便成为了主要选择。为此,结合该管道工程用外径为1 422 mm的X80钢管材技术条件的研究制订过程,对国内外管线钢管技术标准进行了对比分析,同时对外径为1 422 mm X80钢管材技术条件中的化学成分和止裂韧性等关键技术指标及制订过程进行了分析探讨,并对外径为1 422 mm X80钢管的开发过程及产品性能进行了介绍。通过生产试制和产品检测,证明现有技术条件合理有效地解决了化学成分控制、断裂控制、产品焊接稳定性等技术问题,不仅满足了工程要求,而且也适应生产情况,可以保障中俄东线天然气管道的本质安全。该研究成果可为中俄东线建设外径为1 422 mm X80钢天然气管道提供技术支撑,同时对于其他天然气管道工程技术条件的制订也具有指导意义。
文摘High-grade(API 5L X80)and large-diameter(OD 1422 mm)line pipes are used in the Sino-Russian eastern route gas pipeline project for high pressure(12 MPa)transmission,and this can significantly increase the transmission capacity and meet China's energy strategic demand.With the increase of steel grade,transmission pressure,pipe diameter and design coefficient,however,ductile crack of line pipes becomes the dominant crack mode,so it is necessary to focus on crack arrest and control study.In this paper,therefore,an intensive study was performed on the Battelle Two-Curve(BTC)method which is the major solution to the calculation of arrest toughness,as well as the crack resistance curve and decompression curve.Based on the study,the principle and application range of the BTC method were confirmed.In addition,a series of analysis were conducted on the issues which occurred when the BTC method was applied to high-strength,high-toughness line pipe steel,and the commonly used modified approaches to BTC calculation results were also provided.After the crack control scheme of the X80 large OD 1422 mm line pipes for the Russian Bovanenkovo-Ukhta was reviewed,the BTC calculation results were corrected on the basis of the design parameters of the Sino-Russian eastern routine gas pipeline project,the Charpy V-notched(CVN)impact energy which meets the project requirement was finally worked out to be 245 J.
文摘陶瓷-纤维复合靶板是当前轻型防护工程中常用的装甲结构。对于复合装甲的弹道性能国内外学者已经进行了大量的研究,然而对于硬质弹芯和陶瓷-纤维复合靶板作用过程中的破碎特征研究相对较少。弹芯和陶瓷材料的破碎情况对整体复合装甲的防护性能存在较明显的相关性。本文利用12.7 mm的穿甲燃烧弹正侵彻SiC陶瓷-纤维复合靶板,在保证复合靶板面密度相近的情况下,设计了3种不同厚度比的Kevlar/SiC-碳纤维增强环氧树脂基复合材料(T300)-超高分子量聚乙烯(UHMWPE)复合靶板。通过观察回收的弹芯和陶瓷-纤维复合靶板的整体破坏形貌,分析了弹芯和纤维层合板的主要损伤模式。同时对回收的弹芯和陶瓷碎块进行多级筛分称重处理,得到了复合靶板在不同厚度比下弹芯和陶瓷的碎块质量分布符合幂律分布规律。实验结果表明:9 mm SiC+4 mm T300+10 mm UHMWPE的厚度组合在3种不同厚度比中的抗侵彻性能最优,将1 mm厚的SiC陶瓷替换成1 mm厚的碳纤维T300在降低质量的同时可以提高复合装甲的防护能力。复合靶板的失效破坏模式包括陶瓷在高速冲击下形成陶瓷锥和径向裂纹。UHMWPE层合板由拉伸波造成的层间分离现象,背部凸起永久塑性变形及主要为剪切力导致穿孔失效。碳纤维T300层合板损伤形式主要是剪切力导致的十字型脆性断裂,同时伴随冲塞碎块的脱落。弹芯头部主要呈现粉碎性磨蚀破碎,对于较大的弹芯碎块主要是由剪切应力和拉伸应力共同作用下的拉剪失效断裂。陶瓷-纤维复合装甲理想模型是在陶瓷后加入较高刚度的弹性材料同时背板应选择具有高抗拉强度及良好冲击韧性的材料。
