断口分离对X90 焊管断裂阻力影响试验

中国石油集团石油管工程技术研究院· 石油管材及装备材料服役行为与结构安全国家重点实验室

X90 焊管;CVN;DWTT;断裂阻力;断口分离

Test on the effect of fracture separation on the fracture resistance of X90 welded pipe
LI He, FENG Hui, YANG Kun, CHI Qiang, MA Qiurong, HUO Chunyong

CNPC Tubular Goods Research Institute//State Key Laboratory of Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials

X90 welded pipe, CVN, DWTT, fracture resistance, fracture separation

备注

高钢级管道输送是世界天然气管道发展的必然趋势,其中X90 管道裂纹长程扩展的阻力是研究的重点内容之一。为了明确断口分离对X90 焊管断裂阻力的影响,选取中国小批量试制的X90焊管开展了夏比冲击试验(Charpy V-Notch Test,CVN)和落锤撕裂试验(Drop-Weight Tear Test,DWTT),对比分析了CVN 与DWTT 的能量关系、断口分离对DWTT 断裂阻力的影响。研究结果表明:对于X90 焊管,当CVN 能量密度小于450 J/cm2 时,DWTT 与CVN 的能量密度呈线性关系,二者增长速度一致;当CVN 能量密度超过450 J/cm2 时,DWTT 与CVN 的能量密度不再呈线性关系,随着CVN 能量密度增加,DWTT 能量密度缓慢增加。断口分离主要降低了DWTT 总能量中的裂纹扩展功,对起裂功无显著影响。与CVN 试样相比,全厚度的DWTT 试样能够更准确反映断口分离对裂纹扩展阻力的降低作用。(图5表3,参[20]

High-grade steel pipeline transportation is an inevitable development trend of natural gas pipeline in the world, and the resistance to the long-range propagation of cracks in X90 pipeline is one of the important research contents. In order to clarify the effect of fracture separation on fracture resistance of X90 welded pipe, the X90 welded pipe experimentally manufactured in a small scale in China was selected as the research object in this paper. After Charpy V-Notch Test (CVN Test) and Drop-Weight Tear Test (DWTT Test) were carried out, the energy relation between CVN and DWTT and the effect of fracture separation on DWTT fracture resistance were comparatively analyzed. It is shown that as for X90 welded pipe, when the energy density of CVN is lower than 450 J/cm2, the energy density of DWTT is in a linear relation with that of CVN, and their increasing rates are the same; and when the energy density of CVN is higher than 450 J/cm2, the energy density of DWTT increases slowly with the increase of that of CVN. Fracture separation mainly decreases the crack propagation work of the total DWTT energy, but has no significant effect on the fracture initiation work. Compared with the CVN sample, the full-thickness DWTT sample can reflect the reducing action of the fracture separation on the propagation resistance of cracks more accurately. (5 Figures, 3 Tables, 20 References)