通过Gleeble模拟热变形后的等温转变过程,研究了一种微合金管线钢的中温转变行为,对等温过程膨胀量变化情况及相变组织观察,研究了试验钢针状铁素体相变过程及其组织特征。结果表明,试验管线钢针状铁素体转变主要发生在550℃左右,针状铁素体组织中具有较高密度的位错及亚结构,其转变具有形核与生长两阶段特征。 By Gleeble simulating the process of isothermal transformation after thermal deformation, the mid-temperature transformation behavior of a micro-alloyed pipeline steel was studied. The variation of the expansion and the change of microstructure during the isothermal process were studied. The acicular ferrite transformation process and Its organizational characteristics. The results show that the acicular ferrite transformation of the test pipeline mainly occurs at about 550 ℃. The acicular ferrite structure has higher density of dislocations and substructures, and the transformation has the characteristics of two stages of nucleation and growth.