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The correct thickness of the shell solidifying within the primary cooling zone of the continuous casting machine is among the most important parameters assuring the safe operation of the casting pr...

The boundary condition models at the inner and outer surface of the furnace wall have been developed taking into account heat transfer due to radiation and convection. The furnace wall temperature has been calculated from the finite element solution to the transient heat conduction equation. The boundary condition model has been validated using measurements on the laboratory furnace. The heat losses from the chamber walls have been calculated for selected wall structures and modes of the furnace operation. The results of computations have shown essential differences in the energy losses. It has been shown that the total heat losses depend on the chamber wall insulation and on the furnace operation mode for the most types of insulations. The best insulation effect has given the chamber wall made of the two types of the mineral fiber slabs. For this wall the total energy losses below 100 MJ/m 2 has been obtained over 8 days of the furnace operation. Further, low sensitivity to the furnace operation mode has been noticed. This wall insulation can be utilized for heating ingots to the high temperatures and for the heat treatment processes characterized by a long time of the furnace operation.

The paper presents a heat transfer model between two surfaces which are in contact under an external force. The developed heat transfer boundary condition model has been obtained using a new methodology for determining heat flux transferred between two solid surfaces. The methodology consists of two parts: experimental and numerical one. The experimental part involves measurements of temperature at specific points in two samples brought into contact. The numerical part uses an inverse method and the finite element method to calculate the heat flux at the interface.The effect of uncertainty of input parameters for the calculation of heat transfer coefficient has been analysed. These have included: thermal conductivity, specific heat and location of thermocouples. Verification calculation with new value of input parameters for their impact on the accuracy of the solution has been done.The calculations have been performed using original software which uses the inverse method and FEM.

In technological process of steel industry heat transfer is a very important factor. Heat transfer plays an essential role especially in rolling and forging processes. Heat flux between a tool and work piece is a function of temperature, pressure and time. A methodology for the determination of the heat transfer at solid to solid interface has been developed. It involves physical experiment and numerical methods. The first one requires measurements of the temperature variations at specified points in the two samples brought into contact. Samples made of C45 and NC6 steels have been employed in physical experiment. One of the samples was heated to an initial temperature of: 800°C, 1000°C and 1100°C. The second sample has been kept at room temperature. The numerical part makes use of the inverse method for calculating the heat flux and at the interface. The method involves the temperature field simulation in the axially symmetrical samples. The objective function is bulled up as a dimensionless error norm between measured and computed temperatures. The variable metric method is employed in the objective function minimization. The heat transfer coefficient variation in time at the boundary surface is approximated by cubic spline functions. The influence of pressure and temperature on the heat flux has been analysed. The problem has been solved by applying the inverse procedure and finite element method for the temperature field simulations. The self-developed software has been used. The simulation results, along with their analysis, have been presented.

Charge heating in industrial furnaces is a difficult and complex process. There are many physical phenomena which influence heat transfer. At the charge surface heat transfer takes place by radiation and convection. In order to ensure correct operation of the technological system, it is necessary to achieve the required charge temperature in the whole volume and ensure its uniformity.The influence of selected burner locations inside the furnace on the charge temperature has been analysed. The temperature field and its uniformity in the round charge made of steel for hot open die forging have been analysed. The model and numerical calculations were performed with the ANSYS-Fluent 14.5 package.

The study presents the findings of research on developing heating curves of heavy parts for the open die forging process. Hot ingots are heated in a chamber furnace. The heating process of 10, 30, 50 Mg ingots was analyzed. In addition, bearing in mind their high susceptibility to fracture, the ingots were sorted into 3 heating groups, for which the initial furnace temperature was specified. The calculations were performed with self developed software Wlewek utilizing the finite element method for the temperature, stress and strain field computations.

The paper presents the results of research concerning the influence of radiative heat transfer on the strand and mould interface. The four models for determining the heat transfer boundary conditions within the primary cooling zone for the continuous casting process of steel have been presented. A cast slab - with dimensions of 1280×220 mm - has been analysed. Models describing the heat transfer by radiation have been specified and applied in the numerical calculations. The problem has been solved by applying the finite element method and the self-developed software. The simulation results, along with their analysis, have been presented. The developed models have been verified based on the data obtained from the measurements at the industrial facility.

This paper presents the findings of research conducted concerning the determination of thermal boundary conditions for the steel continuous casting process within the primary cooling zone. A cast slab - with dimensions of 1100 mm×220 mm - was analysed, and models described in references were compared with the authors’ model. The presented models were verified on the basis of an industrial database. The research problem was solved with the finite element method using the ProCAST software package.

The paper presents a mathematical model of heat transfer during cooling of hot-rolled rails in the reversing mill. The influence of the radiation shield on the temperature of rolled rails has been analyzed. The heat transfer model for cooling a strip covered by the thermal shield has been presented. The two types of shields build of steel and aluminum sheets separated with insulating layer have been studded. Calculations have been performed with self developed software which utilizes the finite element method.

The paper presents an attempt of modelling liquid steel motion triggered off by electromagnetic stirring. Steel viscosity was calculated on the basis of temperature field determined with the use of stationary heat conduction equation. Velocity field was determined using Navier-Stokes equations and stream continuity equation. Solution was obtained using the finite element method. The developed model allows to carry out quick simulating calculations of fluid flow. Stationary solution was employed, and this allowed to reduce computation time substantially.

A three dimensional numerical model of the heat exchange during a charge heating process in a pusher furnace, using the finite element method, was used in this study. The radiative heat exchange in the furnace chamber was carried out based on two methods: the zone method and the method of basing on the average configuration ratio. In the zone method the flux of radiation energy reaching the surface of the heated charge was determined by performing calculations of brightness in a multi-surface closed system which is the pusher furnace chamber filled with an emitting-absorbing medium. In the second case an average configuration ratio was used by setting the radiation energy flux through linking the walls temperature with the furnace atmosphere temperature.

Identification of the Boundary Conditions in the Continuous Casting of SteelThe results of investigations relating the determination of thermal boundary conditions for continuous casting of steel were presented in the paper. The slab of dimensions 1100 mm x 220 mm was analyzed. In numerical calculations two models were compared. The first was the simple one and it used average heat transfer coefficient in both cooling zones. The second one used complex models in primary and secondary cooling zones. The presented models were verified on basing on an industrial data base. The problem was solved by the finite element method and the commercial numerical packet ProCAST.

The finite element 3D model has been developed to study the heat transfer and fluid flow in the mold region for the continuous steel casting. The strand and mold temperature is controlled by the heat transfer through steel – mold interface. The thermal resistance of interface layer has been modelled taking into consideration the convection heat transfer coefficient between the liquid steel and mold surface as an upper limit and the radiation heat transfer as a lower limit. An empirical equation has been derived to model heat conduction through the steel – mold interface. The computation has been performed to study the model response to thermal resistance of the mold –steel interface and the casting speed.

The industrial rolling mills are equipped with systems for controlled water cooling of hot steel products. A cooling rate affects the final mechanical properties of steel which are strongly dependent on microstructure evolution processes. In case of water jets cooling the heat transfer boundary condition can be defined by the heat transfer coefficient. In the present study one and three dimensional heat conduction models have been employed in the inverse solution to heat transfer coefficient. The inconel plate has been heated to about 900oC and then cooled by one, two and six water jets. The plate temperature has been measured by 30 thermocouples. The heat transfer coefficient distributions at plate surface have been determined in time of cooling.