The microstructure transformation and precipitation behavior of nano-carbides in Ti microalloyed steel during isothermal process were studied by a compression test on a Gleeble 3800 thermomechanical simulator and analyzed by optical microscopy, transmission electron microscopy and other methods. The results show that γ → α phase transformation and TiC precipitation take place in Ti microalloyed steel during the isothermal process, and time–temperature–transformation curve and precipitation–time–temperature (PTT) curve are all of “C”-type. During the isothermal process, the interphase precipitation of TiC mostly occurs at the period of the phase transformation, and the random precipitation of TiC mostly occurs on the ferrite after the phase transformation. The increment in yield strength at the initial stage of isothermal transformation mainly comes from phase transformation strengthening. With the increase in isothermal time, the precipitation hardening effect becomes more important for nucleation and growth of titanium carbides and eventually reaches the maximum value at the precipitation finished point of the PTT curve.

通过在Gleeble 3800热力学模拟器上进行压缩试验，研究了Ti微合金钢在等温过程中纳米碳化物的组织转变和析出行为，并通过光学显微镜，透射电子显微镜等方法进行了分析。结果表明，Ti微合金钢在等温过程中发生了γ→α相变和TiC析出，时间-温度-转变曲线和析出-时间-温度（PTT）曲线均为“ C”型。在等温过程中，TiC的相间析出主要发生在相变阶段，TiC的随机析出主要发生在相变后的铁素体上。等温转变初期屈服强度的增加主要来自相变强化。随着等温时间的增加，沉淀硬化作用对于碳化钛的形核和生长变得更加重要，并最终在PTT曲线的沉淀终点处达到最大值。