The central deformation calculation and analysis of the heavy steel plate for the gradient temperature rolling

The traditional symmetrical rolling process may result in the insufficient central deformation of the heavy steel plate. The gradient temperature rolling (GTR) based on the ultra-fast cooling was adopted in order to improve the central deformation and keep the deformation along the thickness to be well distributed. The temperature and strain field of the gradient temperature rolling were obtained by the thermo-mechanical coupling finite element method combined with different surface heat transfer coefficient, plate thickness, work roll diameters and so on. The calculated results showed that the deformation was more likely to penetrate into the core compared with uniform temperature rolling (UTR). The central equivalent strain with GTR was increased by 44.3% maximum compared with UTR in the same case. The deformation along the thickness was well distributed compared to the UTR. The central deformation gradually increases with the increase of reduction rate, surface heat transfer coefficient, work roll diameters and speed ratio, while the central deformation almost unchanged with linear velocity. Furthermore, industrial application showed the deformation can penetrate into the core compared with the UTR and it can help to eliminate the band structure. In this study, the influencing law of equivalent strain along the thickness with different parameters was summarized. The fitting model to calculate the central equivalent strain after GTR was established according to the numerical results. It can provide reliable theory and technology support for the setting of various parameters for GTR.