Abstract: The forging model for cold rolling is one of the rolling models which is used in rolling calculations. In this model, the final rolling pressure is an average value and it is not as accurate for actual and industrial cases. Also, by using forging model, friction hill curves are plotted due to the central point of rolling bite length while frictional stresses intersect at the neutral point of rolling bite. In this study, a new model based on the forging model is presented to determine the rolling pressure during cold rolling process for using in a reversing tandem mill, where this is called “Improved forging model”. In the proposed model, the intersection of the frictional forces is the neutral point. Finally, the computing results from this new model coincide well with the precedent investigations.

In this paper an analytical model for cold rolling of strip has been described. This model is developed based on the slab method of analysis and the hydrodynamic lubrication. The characteristics of rolling are obtained from the equations of equilibrium and the plate was allowed to strain harden assuming that the lubricant behaves as a Newtonian fluid. The shear stress to the plate is obtained by calculating the thickness of the lubricant film by employing a viscosity-pressure-temperature relation. The governing equations are obtained by composing these relations and the final differential equations have been solved. From the solution of the final equation, the rolling force torque and shear stress to the plate are calculated. To verify the validity of the proposed model, these values are compared with experimental and analytical results of other investigators. It was also noted that by employing the proposed analytical model, a large amount of computation time and costs are saved.

Chatter is a particular case of self-excited vibrations, which arise in rolling operations because of the interaction between the structural dynamics of the mill stand and dynamics of the rolling process. The model presented here has two sub models one for structure of the mill and the other for the rolling process. The structure of a mill stand modeled as a system of linear spring and lumped masses in order to simulation the interaction between the rolls.In this paper, to analyze the chatter vibration a dynamic model of cold rolling process using finite element method (FEM) is considered. The influence of rolling parameters such as rolling speed, reduction and friction coefficient on chatter vibration is investigated and it was showed that the possibility of chatter onset increased by raising the rolling velocity and decrease friction coefficient. Predicted values of the model are in good agreement with that of the experiments as well as the values obtained by other researchers.

Strip tearing during cold rolling process has always been considered among the main concerns for steel companies, while several works have been done so far regarding the examination of this issue. In this paper, experimental data from cold rolling tandem mill is used for detecting strip tearing. Sensors are placed across the cold rolling tandem mill, to collect information on parameters (such as angular velocity of the rolls, voltage and the electrical current of electrical motors driving rolls, roll gap, and strip tension force between rolls) directly from the cold rolling tandem mill. The information includes two modes: perfect rolling and ruptured rolling. A neural network is designed by means of MATLAB software and, then, trained using the information from the related data files. Finally, the neural network is examined by new data. It is concluded that the neural network has good accuracy in distinguishing between perfect and defected rolling.

Dimensional control of the work-piece in steel industry is of important interest. The main aspects in overcoming the thickness control are variations in material strength due to variations in chemical composition, work-piece temperature, reduction and the strain rate applied to the work-piece. In this paper based on the main parameters affecting the rolling force an attempt been made to give a more accurate prediction for the flow stress in a steel rolling finishing mill. Predicted values of the model are compared with those of the experimental values which are shown to be in good agreements.

Root perforation may occur at any stage of endodontic treatment and is mostly due to iatrogenic injury and may compromise the outcome of endodontic treatment. Repairing a perforation is difficult and the prognosis depends on various factors such as time, site and size of perforation, and the patient’, s overall health status. Hence, choosing the most appropriate material can be critical for the dentist. In this case report of a strip‑, perforation repair, an mineral trioxide aggregate‑, like material (cold ceramic) that has been shown in previous studies to have favorable properties, was successfully used.

The objectives in the cold rolling process include improved sheet surface quality and enhanced steel mechanical strength. Given the increasing demand for higher steel surface quality, more rapid production, and thinner steel plates, more attention has been directed toward the parameter of temperature in cold rolling as a means of achieving the above objectives. Due to the friction between work rolls and steel sheet caused during the cold rolling process and because of temperature changes of the work piece during plastic work, a non-uniform temperature distribution results along the work roll axial direction which ultimately leads to improper and undesirable expansion of the work roll along its axis. This, in turn, causes an uneven work roll slide on sheet surface; hence, the uneven and wavy steel surface. In this study, we used headers with a variety of nozzles for cooling the work rolls in order to achieve uniform temperature distribution and thermal expansion of the work roll. In this method, the cooling system is applied to the work roll in such a way that the work roll gains the desired efficiency in terms of both optimized energy consumption and work roll thermal expansion.

In this paper a mathematical model based on the finite element method is presented to predict the strain field and the roll-force during hot strip rolling process. The model is capable to predict the effect of various factors such as work hardening of rolled metal, variation of temperature during hot rolling, rolling speed, and friction on the strain field within the rolled metal. To verify the validity of the model, a comparison was made between the theoretical and the experimental results of hot rolling of steel strip. A good agreement was found between the two sets of results.

The final hot strip profile is a superposition of the roll initial crown, the roll bending and flattening crown, the roll wearing crown and the roll thermal crown. In this research, linear regression models are proposed to predict the roll force, the roll wearing crown and the roll thermal crown using experimental data provided by Mobarake Steel Complex (MSC). The Euler-Bernoulli beam theory based on elasticity approach is also used to predict the roll bending and flattening crown. Finally, the work roll initial crown in order to obtain desired strip profile in hot rolling is predicted utilizing a computer programming. The obtained initial crowns are then used for seven stands of an actual roll schedule for hot strip mill of MSC. The measured strip profile shows a good agreement with the desired one for the mentioned mill.