Research on the Hot Deformation Behavior and Processing Map of Nb‐Microalloyed 14Cr1MoR Steel

14Cr1MoR steel is widely used for medium‐ and high‐temperature pressure vessels owing to its excellent creep resistance and resistance to hydrogen corrosion. During hot working, complex deformation mechanisms may lead to microstructural inhomogeneity, degradation of mechanical properties, and cracking. Single‐pass hot‐compression tests are conducted on Nb‐microalloyed 14Cr1MoR steel using a DIL805 dilatometer at 900–1150°C and strain rates of 0.1–10 s −1 to characterize its hot‐deformation behavior. An Arrhenius‐type constitutive model is established, and the Zener–Hollomon parameter together with the Prasad instability criterion is used to construct processing maps and evaluate workability. The results indicate that at 1050–1100°C and 0.1–1 s −1 , the material exhibits high power dissipation efficiency and stable flow. These findings provide guidance for optimizing industrial hot‐working parameters for 14Cr1MoR steel.