A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API (American Petroleum Institute) X80 strip steel was investigated in this work. Microstructural analysis showed that th...A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API (American Petroleum Institute) X80 strip steel was investigated in this work. Microstructural analysis showed that the band structure of bainite elongated along the rolling direction works as the initiation sites of separation. The propagation of separation can be promoted not only by the occurrence of the band structure of martensite/austenite constituent, prior austenite grain boundaries, and elongated bainite, but also by fine acicular ferrite and bainite. Wide separation formed in the former case, while the narrow one appeared in the latter case. acicular ferrite in thick-walled X80 pipeline steel in order Some methods were proposed to obtain fine and homogeneous to minimize the occurrence of separation.展开更多
综述了按GB/T 8363与API RP 5L3等标准所执行的铁素体钢落锤撕裂试验(DWTT)技术的发展概况及其在评价高强度、高韧性金属材料动态断裂性能,特别是在韧断止裂性能中的应用,如高等级管线钢、压力容器用钢以及高止裂性能船板用钢等。具体而...综述了按GB/T 8363与API RP 5L3等标准所执行的铁素体钢落锤撕裂试验(DWTT)技术的发展概况及其在评价高强度、高韧性金属材料动态断裂性能,特别是在韧断止裂性能中的应用,如高等级管线钢、压力容器用钢以及高止裂性能船板用钢等。具体而言,第一代DWTT试验机具有较高打击能量冲断试样暴露断裂面,仅用于评价设定温度断口剪切面积分数pSA指标;第二代试验机可实测试样的DWTT吸收能,是夏比冲击技术在大尺寸试样与实物性能评测中的重要拓展;第三代试验机具备仪器化测力分析功能,可结合弹塑性断裂力学原理开展动态断裂性能评价,特别是评估管线钢的临界裂纹尖端张开角度指标,即ψCTOA,c。展开更多
使用常规落锤试验机与大能量摆锤冲击试验机两种机型,对准762 mm×31.8 mm X70MO直缝埋弧焊厚壁海管进行了DWTT减薄试样(单面减薄及双面减薄)与全壁厚试样系列温度试验,利用Boltzmann函数对试验数据进行了拟合,得出了试验温度与断...使用常规落锤试验机与大能量摆锤冲击试验机两种机型,对准762 mm×31.8 mm X70MO直缝埋弧焊厚壁海管进行了DWTT减薄试样(单面减薄及双面减薄)与全壁厚试样系列温度试验,利用Boltzmann函数对试验数据进行了拟合,得出了试验温度与断口剪切面积的关系曲线,确定了减薄试样与全壁厚试样的韧脆转变温度,对其进行了对比分析。结果验证了厚壁钢管使用减薄试样时,应降低相应的试验温度;同时得出在相同试验温度下,单面减薄试样的试验结果优于双面减薄试样(壁厚中心试样)等结论,并提出了相关建议,希望对以后的试验研究有借鉴作用。展开更多
文摘A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API (American Petroleum Institute) X80 strip steel was investigated in this work. Microstructural analysis showed that the band structure of bainite elongated along the rolling direction works as the initiation sites of separation. The propagation of separation can be promoted not only by the occurrence of the band structure of martensite/austenite constituent, prior austenite grain boundaries, and elongated bainite, but also by fine acicular ferrite and bainite. Wide separation formed in the former case, while the narrow one appeared in the latter case. acicular ferrite in thick-walled X80 pipeline steel in order Some methods were proposed to obtain fine and homogeneous to minimize the occurrence of separation.
文摘综述了按GB/T 8363与API RP 5L3等标准所执行的铁素体钢落锤撕裂试验(DWTT)技术的发展概况及其在评价高强度、高韧性金属材料动态断裂性能,特别是在韧断止裂性能中的应用,如高等级管线钢、压力容器用钢以及高止裂性能船板用钢等。具体而言,第一代DWTT试验机具有较高打击能量冲断试样暴露断裂面,仅用于评价设定温度断口剪切面积分数pSA指标;第二代试验机可实测试样的DWTT吸收能,是夏比冲击技术在大尺寸试样与实物性能评测中的重要拓展;第三代试验机具备仪器化测力分析功能,可结合弹塑性断裂力学原理开展动态断裂性能评价,特别是评估管线钢的临界裂纹尖端张开角度指标,即ψCTOA,c。
文摘使用常规落锤试验机与大能量摆锤冲击试验机两种机型,对准762 mm×31.8 mm X70MO直缝埋弧焊厚壁海管进行了DWTT减薄试样(单面减薄及双面减薄)与全壁厚试样系列温度试验,利用Boltzmann函数对试验数据进行了拟合,得出了试验温度与断口剪切面积的关系曲线,确定了减薄试样与全壁厚试样的韧脆转变温度,对其进行了对比分析。结果验证了厚壁钢管使用减薄试样时,应降低相应的试验温度;同时得出在相同试验温度下,单面减薄试样的试验结果优于双面减薄试样(壁厚中心试样)等结论,并提出了相关建议,希望对以后的试验研究有借鉴作用。