在变形温度950~1 050 ℃、应变速率0.01~5 s^-1下对F45MnVS非调质钢进行不同变形量（5%~56%）的单道次压缩试验，研究了变形温度、应变速率和变形量对该钢变形行为和晶粒尺寸的影响；基于试验数据建立动态再结晶临界应变模型和平均晶粒尺寸模型，嵌入Deform软件中模拟了试验钢的动态再结晶平均晶粒尺寸。结果表明：随着变形量或应变速率的增大，或者变形温度的降低，试验钢的平均晶粒尺寸减小；较高应变速率下加工软化导致的应力下降不明显，动态再结晶程度较小，较低应变速率下则相反；模拟得到的再结晶平均晶粒尺寸与试验结果较吻合，且平均晶粒尺寸随变形温度、应变速率和变形量的变化规律与试验结果相符。

The F45MnVS non-quenched and tempered steel was subjected to single-pass compression tests with different deformation amounts (5%-56%) at deformation temperatures of 950-1 050 ℃ and strain rates of 0.01-5 s^-1. The effects of deformation temperature, strain rate and deformation amount on the deformation behavior and grain size of the steel were studied. According to the experimental data, the dynamic recrystallization critical strain model and the average grain size model were established, and the average size of dynamic recrystallization grains was simulated with Deform software embedded with the two models. The results show that with increasing deformation amount or strain rate, or decreasing deformation temperature, the average grain size of the test steel decreased. At relatively high strain rates, the decrease in stress by work softening was not obvious, and the dynamic recrystallization degree was relatively low; the opposite was true at relatively low strain rates. The average recrystallization grain size obtained by the simulation was in good agreement with the experimental results, and the variation of the average grain size with the deformation temperature, strain rate and deformation amount was consistent with the experimental results.