# The Heat Transfer Analysis of an Acting-type Heat Retention Panel used in a Hot Rolling Process
## 1 Introduction
[5] obtained numerous in-situ data from a steel plant, including the size and properties of slab, the temperature at the exit of the slab reheating furnaces, and the size and the temperature distribution of the transfer bar after rough rolling. They used the Microsoft Visual Basic program to design a computer-aided design program to calculate effect of the temperature of the transfer bar on the finishing rolling force. [PERSON] [6] analyzed the advantages and disadvantages of a traditional passive heat retention panel, an acting-type heat retention panel, and a heat coil box. The results indicated that a traditional passive heat retention panel consumes the least energy but it is inefficient for heat retention. Although an acting-type heat retention panel consumes the most energy, it is the most effective for retaining heat in the transfer bar. A heat coil box exhibits a good performance for heat retention and consumes less energy than an acting-type heat retention panel, but the cost of installation is the most expensive. [PERSON] et al. [7] used the finite difference method (FVM) combined with heat conduction and heat convection to investigate the impact of the rollers beneath conveyors on slab. [PERSON] et al. [8] studied the thermal fatigue effect of the rollers beneath the conveyors on slab. [PERSON] et al. [9] used the nonlinear heat transfer equation to predict the temperature of the steel on the run-out table (ROT) process. The results show that the performance with a cooling stop temperature concept to the temperature and property of the steel was greatly improved. [PERSON] et al. [10] investigated the strip steel, which was heated by induction heater by the finite element method. They found that the temperature difference became more and more obvious with the increase of thickness. [PERSON] et al. [11] developed a program which allows users to set-up their hot strip mill configuration and simulate the mechanical properties of the steel in the hot rolling process. The program includes reheating furnace, roughing mill stands, heat retention equipment (panels and coil box), finishing mill stands, the run-out table, and the mill exit area. [PERSON] [12] designed a model to predict strip temperature from the roughing mill exit to the finishing mill exit. The results were compared to those from the plant measurements, and it was shown that this model worked very well. [PERSON] et al. [13] used a semi-industrial physical model to simulate thermomechanical rolling and controlled cooling of advanced high-strength steels with increased Mn and Al content. The results indicated that the high-quality strip samples with a thickness up to 3.3 mm could be obtained by using heat retention panels. [PERSON] and [PERSON] [14] developed a transient 3D finite element model to obtain thermal variations during the hot rolling process. The numerical model showed that the temperature results can provided a relatively accurate prediction with less than 10% deviation. [PERSON] et al. [15] studied the active tunnel furnace in order to minimize heat losses of the transfer bar on the roller table between roughing mill and finishing mill. With traditional passive heat retention panels, the temperature difference in the head and the tail of the carbon transfer bar was about 20 \({}^{\circ}\)C. They found that the active heat retention panels was able to compensate for this drop in temperature. Based on the studies referenced above, it is important to decrease the temperature difference between the head and the tail of the transfer bar to enhance the quality of steel products. The traditional passive heat retention panel is widely used in many steel plants, but its ability to hold temperature is inefficient. In order to solve this problem, it is necessary to develop other heat retention equipment as soon as possible.