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通过合理的组织、成分设计,在实验室试制成功X100管线钢。利用光学显微镜、透射电镜与背散射电子衍射技术(EBSD),研究了X100钢不同组织构成对力学性能的影响规律及其合理的控冷制度,并通过Gleeble-1500热模拟机获得了试验钢的CCT曲线。结果表明,少量AF(Acicular Ferrite)、GB(Granular Bainite)组织的出现,可使原奥氏体晶粒得到分割,抑制板条束的过分长大,使板条贝氏体束的有效晶粒尺寸得到显著细化,钢板具有最优的细化组织,塑韧性得到明显改善;冷却速度为20~25℃/s,终冷温度为380℃时,钢板可获得最佳的组织构成与最优的综合力学性能,屈服强度为775 MPa,抗拉强度为855 MPa,伸长率为16.6%,冲击功(-20℃)为218 J。
Through reasonable organization and composition design, X100 pipeline steel was successfully made in laboratory. The effects of different microstructures of X100 steel on the mechanical properties and the reasonable cooling control system were studied by optical microscope, transmission electron microscopy and backscattered electron diffraction (EBSD). The mechanical properties of the test steel were obtained by Gleeble-1500 thermal simulator CCT curve. The results show that the presence of a small amount of Acicular Ferrite and GB (Granular Bainite) can separate the original austenite grain, inhibit the excessive growth of lath, and make the effective grain size of lath bainite The size of the steel sheet is remarkably refined. The steel plate has the best refinement structure, and the plasticity and toughness of the steel plate are obviously improved. When the cooling rate is 20-25 ° C / s and the final cooling temperature is 380 ° C, the optimal structure and optimum The tensile strength is 775 MPa, the tensile strength is 855 MPa, the elongation is 16.6% and the impact energy (-20 ℃) is 218 J.