高应变用途双相显微组织超高强度管线钢的开发

Development of Ultra-High Strength Linepipes with Dual-Phase Microstructure for High Strain Application

为开发具有更高变形性能的高强度管线钢开展了广泛的研究,提高变形性能的关键技术之一是双相显微组织的控制。通过应用热机械控制轧制工艺(TMCP),即控制轧制加快速冷却的工艺,可以得到具有铁素体-贝氏体显微组织的钢板。采用了低碳无硼钢,以便能够控制轧制后的冷却和以最大冷却速率的快速冷却过程中形成铁素体,提高强度到X120级别。在快速冷却后还采用了在线热处理工艺,以提高基体材料的夏比冲击功。通过双相显微组织控制进行了X120高变形性能管线钢的试生产。本文介绍了X120管线钢的显微组织和力学性能。

Extensive studies have been conducted to develop high strength linepipes with higher deformability.One of the key technologies for improving deformability is dualphase microstructural control.Steel plate with ferrite bainite microstructure can be obtained by applying thermo-mechanical controlled processing（TMCP）,a process of controlled rolling and accelerated cooling.Low carbon,boron-free steels were used to enable the ferrite formation during cooling after controlled rolling,and accelerated cooling with an ultimate cooling rate enhanced the strength up to the X120 grade.Heat-treatment On-line Process was also applied after accelerated cooling in order to improve the Charpy energy of base material.Trial production of X120 high deformability linepipe was conducted by applying dual-phase microstructural control.Microstructural and mechanical properties of X120 linepipe are introduced in this paper.