The constitutive relationship is the basis for studying the material processing technology and controlling the quality of products. Data and models of the plastic flow behavior of materials are often required during the manufacturing process. Therefore, establishing constitutive models with high precision and generalization and enriching material database is of great significance for optimizing processing technology and product quality of the material. Based on the Gleeble thermal compression test results, the essential relationship of 25 steel between the flow stress and thermal–mechanical state variables, such as temperature, strain rate, and strain, is quantitatively discussed for the first time. Combined with the Zener–Hollomon parameter and considering the influence of strain compensation, the constitutive model of 25 steel is built by the hyperbolic-sine equation over the full strain range. In the modeling process, the influence of strain on material constants is characterized by polynomial fitting. The selection basis of polynomial order is discussed in-depth, and the inconsistency between calculation accuracy and fitting effect is clarified. Finally, the accuracy of the model is analyzed, and the generalization and applicability are discussed. It is proved that the developed model can accurately predict the flow behavior of materials in the full strain range.

本构关系是研究材料加工技术和控制产品质量的基础。在制造过程中通常需要材料的塑性流动行为的数据和模型。因此，建立高精度，泛化的本构模型，丰富材料数据库对于优化材料的加工工艺和产品质量具有重要意义。基于Gleeble热压缩测试结果，首次定量讨论了25钢在流变应力与热机械状态变量（例如温度，应变速率和应变）之间的基本关系。结合Zener-Hollomon参数并考虑了应变补偿的影响，通过双曲正弦方程在整个应变范围内建立25钢的本构模型。在建模过程中，应变对材料常数的影响以多项式拟合为特征。深入讨论了多项式阶数的选择依据，阐明了计算精度与拟合效果之间的矛盾。最后，分析了模型的准确性，讨论了模型的推广和适用性。实践证明，所建立的模型能够准确预测材料在整个应变范围内的流动行为。明确了计算精度与拟合效果之间的矛盾。最后，分析了模型的准确性，讨论了模型的推广和适用性。实践证明，所建立的模型能够准确预测材料在整个应变范围内的流动行为。明确了计算精度与拟合效果之间的矛盾。最后，分析了模型的准确性，讨论了模型的推广和适用性。实践证明，所建立的模型能够准确预测材料在整个应变范围内的流动行为。