厚壁X80管线钢管不同壁厚处的低温拉伸性能研究

为了研究厚壁X80管线钢管不同壁厚处的显微组织与低温环境下拉伸性能的关系，利用光学显微镜、电伺服拉伸试验机和低温试验箱等分析手段对壁厚为32.1 mm的X80管线钢管的显微组织和拉伸性能进行了分析。试验结果表明:由于X80管线钢管壁厚较厚，显微组织在厚度方向上的整体均匀性较差，中心层的组织晶粒度与外层相比较为粗大。温度由20 ℃下降至－60 ℃时，3组试样的抗拉强度、屈服强度均有上升趋势；在同一温度下，3组试样强度由大到小的顺序为:外层＞内层＞中心。

Research on Low Temperature Tensile Properties of Thick Wall X80 Pipeline Steel Pipe at Different Wall Thicknesses

In order to study the relationship between the microstructure of the thick wall X80 pipeline steel pipe with different wall thicknesses and the tensile properties at the low temperature, the microstructure and tensile properties of X80 pipeline steel pipe with a wall thickness of 32.1 mm were analyzed by means of the optical microscope, the electric servo tensile testing machine and the low temperature test chamber. The test results show that the wall thickness of X80 pipeline is thick, the uniformity of the microstructure in the thickness direction is poor, and the microstructure grain size of the central layer is larger than that of the outer layer. When the temperature dropped from 20 ℃ to －60 ℃, the tensile strength and yield strength of the three groups of samples showed an upward trend. At the same temperature, the strength order of the three groups of samples is as follows: outer > inner > center.