Simulation and Experimental Study on the Effect of Differential Speed Rolling on Microstructure of AH36 Marine Steel During Asymmetric Rolling

To clarify the effect of speed ratio on the microstructure and properties of AH36 marine steel during differential speed rolling (DSR), hot compression tests were conducted at 1050–1200 °C, 0.01–1 s −1 , and ε = 0.7, and a hyperbolic‐sine Arrhenius constitutive equation was established. The constitutive equation was implemented in DEFORM‐3D to simulate DSR under different speed ratios, and the finite‐element model was validated using rolling‐force measurements. A dynamic recrystallization cellular automaton (DRX‐CA) model was then coupled with the macroscopic simulation to predict grain evolution. The results show that both simulated and experimental rolling forces decreased with increasing speed ratio. Increasing the speed ratio promoted grain refinement and enhanced the simulated DRX behavior. At a speed ratio of 1.3, the average grain size decreased from 32.2 to 24.8 μm, corresponding to a refinement of 22.9%, and the average deviation between simulation and experiment was below 10%. Tensile tests showed that both strength and ductility improved with increasing speed ratio, and the reduction of area increased by 7.4% compared with synchronous rolling. These results indicate that the coupled constitutive‐FE‐DRX‐CA framework can reasonably predict grain refinement during DSR and support speed‐ratio optimization for AH36 marine steel.