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用光学显微镜、扫描电镜、透射电镜和EBSD等方法研究了X100管线钢热连轧钢带的微观组织、析出物、晶粒尺寸等对X100管线钢强韧性的影响。结果表明,通过合理的成分设计和TMCP工艺得到的X100管线钢的平均有效晶粒尺寸约为2.38μm,晶内含有大量位错和亚结构;显微组织由粒状贝氏体、板条贝氏体和M/A岛组成,组织中粒状贝氏体含量较多,板条贝氏体含量较少,M/A岛尺寸较小,弥散分布;细小的第二相能有效钉扎位错的移动,产生沉淀强化效果;实验钢的抗拉强度高于970 MPa,屈服强度高于800 MPa,-40℃以上的Charpy冲击功大于250 J,韧脆转变温度在-40℃与-60℃之间。
The effects of microstructure, precipitates and grain size on the strength and toughness of X100 pipeline steel were studied by means of optical microscope, scanning electron microscope, transmission electron microscope and EBSD. The results show that the average effective grain size of X100 pipeline steel obtained by reasonable composition design and TMCP process is about 2.38μm, and contains a large number of dislocations and substructures. The microstructure consists of granular bainite, Body and M / A island. The content of granular bainite and lath bainite in the tissue are small, while M / A island is small and disperse. The small second phase can effectively pin dislocation The tensile strength of the experimental steel is higher than 970 MPa, the yield strength is higher than 800 MPa, the Charpy impact energy of the steel above -40 ° C. is greater than 250 J, the transition temperature of the ductile-brittle transition temperature is between -40 ° C. and -60 ° C. between.