低碳钢热变形过程中奥氏体动态再结晶问题分析

Dynamic Recrystallization of Low Carbon Steel During Heat Deformation Process

以Q235低碳钢为研究对象,研究其在不同温度和应变速率热变形过程中的膨胀曲线改变,揭示低碳钢在动态再结晶过程的临界条件和晶粒尺寸。结果表明,当变形温度大于850℃,应变速率在0.1~60.0 s-1之间,应力应变曲线上对应峰值为动态再结晶过程。奥氏体动态再结晶发生的前提条件是εc=3.628×10-4DA0.21Z0.17,且可以通过控制钢的冷却速度获得较小尺寸的铁素体晶粒。

Using Q325 low carbon steel as research object, the strain rate, grain size and the critical conditions of dynamic recrystallization at different heat deformation conditions were analyzed. The results show that, when temperatures is higher than 850 ℃ with strain rate between 0.1 to 60.0 s-1, the peak in stain-stress curve is correspond to the steel dynamic recrystallization process. The critical condition of the steel dynamic recrystallization process is εc=3.628×10-4DA0.21Z0.17, and ferrite with Small grain size can be achieved by changing the material cooling rates.