Predicting stress and flatness in hot-rolled strips during run-out table cooling

Flatness defects are complicated issues that occur during hot-rolled strip production. With more research on flatness control during the rolling process, flatness control technology during the rolling stage has improved. However, there is no online method for measuring strip flatness during the cooling stage after rolling. Therefore, this study focused on the evolution of stress and flatness of steel strips during run-out table cooling. Providing guidance for strip flatness controlled during run-out table cooling. A fully coupled finite element model based on temperature, phase transitions, and strain was developed. The calculated results of the model were in good agreement with the measured data. Furthermore, the patterns of evolution of stresses and flatness of the steel strip during run-out table cooling were obtained. The results showed that large compressive stresses formed along the edge region, as well as small tensile stresses in the middle region, causing edge wave defects to occur. With an increase in the initial temperature drop distance of the strip edge area, the edge wave degree also increased. Moreover, the cooling efficiencies of the upper and lower steel strip surfaces were not consistent, resulting in uneven distributions of stresses along the thickness of the material. Finally, the longitudinal and transverse warpage phenomena during the cooling process were discussed in detail.

Automated summary

This study investigates the evolution of stress and flatness of steel strips during run-out table cooling by establishing a finite element model. The results show that uneven stress distribution during the cooling process can cause flatness defects, and the degree of edge wave is related to the initial temperature drop distance in the edge region of the strip.