中文摘要：

用Gleeble-3500热模拟试验机测定了一种高Mn、高NbX80管线钢连续冷却转变（CCT）fm线，研究热变形对连续冷却相变行为的影响。结果表明：变形可以促进多边形铁素体和珠光体相变，抑制针状铁素体相变，同时可以提高相变温度，细化相变组织。变形及冷却过程中Nb（C，N）的析出，降低了奥氏体的稳定性，加速相变，但抑制铁素体品粒长大，细化室温组织。

英文摘要：

Continuous cooling transformation （CCT） curves of a high-Mn Gleeble-3500 thermal mechanical simulator, furthermore, the effect of hot and high-Nb X80 pipeline steel were constructed by means of deformation on continuous cooling transformation behaviors was researched. The results show that hot deformation can promote the polygonal ferrite （PF） and pearlite （P） transformation and delay acicular ferrite （AF） phase transformation. Meanwhile, the hot deformation can increase the phase transformation temperature, and refine the microstructure. The precipitates of Nb（ C, N） during deformation and cooling process can decrease the stability of austenite, accelerate the transformation, restrain the grain growth of ferrite and refine the final microstructure.