Sharif Digital Repository

Prediction of temperature distribution within work-rolls during the hot strip rolling process is of great importance to mill designers because of the significant role it plays in the product's dimensional accuracy and roll life. The present article employs the unsteady state heat transfer equation with time-dependent boundary conditions, as well as a two-dimensional finite element method, to determine work-roll temperature variations during continuous hot strip rolling. To achieve an accurate temperature field, the authors consider the effects of different factors, including work-roll and metal thermal relationship, idling work-roll revolutions, and the effects of various process parameters... 

Predicting temperature distributions in the work-rolls during the hot slab rolling process is of great importance to mill designers. This is because the temperature distribution and the dimensional accuracy of the slab being rolled are both dependent on the work-roll temperature. In addition, the life of the roll is also a function of its own temperature distribution. In this paper, the unsteady state heat transfer equations with time dependent boundary conditions are coupled with a two-dimensional finite element method to predict the work-roll temperature distribution during the continuous hot slab rolling process. To achieve an accurate temperature field, the effects of various factors... 

An integrated mathematical model was developed to study the thermo-mechanical behavior of strips and work-rolls during warm rolling process of steels. A two-dimensional finite element analysis was first employed to solve for the thermo-mechanical response of the rolled strip under steady-state conditions. The calculated roll pressure and temperature fields were then used to apply proper boundary conditions for solving the governing thermo-mechanical problem for the work-roll. The obtained results indicate that in warm strip rolling of steels, the thermal and mechanical stresses developed within the work-roll are comparable; however, the more significant influence is due to heating and... 

Temperature variations of work-rolls in the process of hot rolling of slabs were analyzed by solving heat conduction equation with time-dependent boundary conditions. The Raylieght-Ritz and the finite-element methods were employed to solve the governing equation. To improve the accuracy, the thermal relationship between rolling metal and work-rolls was taken into account as well as the effects of different parameters such as interface heat transfer coefficient, rolling speed, and slab initial temperature were considered in the calculations. To verify the employed model, a comparison was made between the predicted and the recorded time-temperature history and good agreement was observed.... 

A mathematical model was developed to assess thermomechanical behavior of work rolls during warm rolling processes. A combined finite element analysis-slab method was first developed to determine thermal and mechanical responses of the strip being rolled under steady-state conditions, and then, the calculated roll pressure and temperature field were utilized as the governing boundary conditions for the thermomechanical problem of the work roll. Finally, the thermomechanical stresses within the work rolls were predicted by a thermoelastic finite element approach. The results of the model indicate that, in warm strip rolling, thermal and mechanical stresses developed in the work rolls are... 

A mathematical model is proposed for the determination of the thermo-mechanical stresses in work-rolls during hot-strip rolling. The model describes the evolution of the temperature fields in the work-roll and in the work-piece, and in the latter the plastic heat generation is taken into account. The frictional heat generated on the contact surface is also included. The problem is treated in two steps. First, a numerical method is developed for the analysis of the coupled thermal problem of the temperature distributions within the work-roll and metal being rolled, while an admissible velocity field is employed to estimate the heat of deformation. In the second step, the finite-element method... 

A finite element analysis was developed to determine thermomechanical behaviours of strip and work-roll during cold rolling process under practical rolling conditions. The velocity field was first obtained using a rigid-plastic finite element formulation and then it was used to assess the strain and stress distributions within the strip and at the same time, a thermal finite element model based on streamline upwind Petrov-Galerkin scheme was employed to predict temperature distribution within the metal being rolled. In the next stage, the predicted temperature and stress fields at the contact region of strip/work-roll were employed as the boundary conditions to evaluate the thermomechanical... 

In this work, a combined finite element analysis and upper bound technique is employed to assess temperature field and thermal stress distribution within the work rolls during continuous hot strip rolling process. Two-dimensional finite element analysis is utilised to simultaneously predict temperature fields within the rolling metal and the work roll as well as thermal stresses in the work rolls. In order to calculate the velocity field and the rate of heat of deformation, an upper bound solution is coupled with the employed finite element analysis. The utilised model makes it possible to estimate the effects of different parameters such as idling revolutions and initial temperature on... 

In this paper an integrated model has been developed that is capable of considering the effects of process parameters on the thermo-mechanical behaviour of the work-roll and the strip during hot rolling operations. The commercially finite element package ABAQUS is utilized to solve the governing equations, while an elasto-viscoplastic material behaviour is utilized in the model. The model may be employed in single-pass as well as multi-pass rolling layouts. Various aspects of the hot rolling process are predicted including temperature field and thermo-mechanical stresses within the work-roll as well as temperature, strain, and residual stresses distributions within the strip. To assess the...