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In this work, a rolling simulation system for the hot rolling of steel is elaborated. The system is capable of simulating rolling of slabs and blooms, as well as round or square billets, in different symmetric or asymmetric forms in continuous, reversing, or combined rolling. Groove geometries are user-defined and an arbitrary number of rolling stands and distances between them may be used. A slice model assumption is considered, which allows the problem to be efficiently coped with. The related large-deformation thermomechanical problem is solved by the novel meshless Local Radial Basis Function Collocation Method. A compression test is used to compare the simulation results with the Finite Element Method. A user-friendly rolling simulation application has been created for the industrial use based on C# and .NET framework. Results of the simulation, directly taken from the system, are shown for each type of the rolling mill configurations.In this paper, recent developments of our comprehensive rolling simulation system, which includes a rolling-specific and user-friendly man-machine interface, MM solution procedure, and a comprehensive set of technologically important graphical outputs for simulating different types of rolling mills, is explained. The system was previously able to simulate schedules with flat, round [16], and non-symmetric grooves [17]. The upgrades of the system, which allow the system to simulate the reversing rolling mill process, are of a particular focus in the present paper. Rolling schedules are distinguished as flat, round, or reversing rolling types. Each type may consist of multiple rolling schedules. Material model, roll gaps, and type of the grooves, as shown in Figure 1, are all user-defined, and this helps the user to make his own sensitivity studies. Another major importance of this paper is to provide the reader with both the details of the physical model, as well as the details of the numerical solution, which are rare to see in recent rolling publications. The reason is that a vast majority of the rolling simulations employ well-known and well-optimized commercial FEM-based codes. Metals 2018, 8, x FOR PEER REVIEW 2 of 21 Metals 2019, 9, 788 3 of 21Later in this paper, the physical model, solution procedure, numerical implementation, compression test comparison of our meshless approach with FEM, and the simulation results for flat, round, and reversing mills are shown. Solution MethodThe slice model assumption, governing equations, corresponding initial and boundary conditions, and the numerical solution is explained in this section. Slice ModelRolling of steel is a very complex 3D solid mechanics problem. Therefore, the numerical simulation of rolling requires an extremely high computational power and time, proportional with the desired accuracy. In order to optimize the computational time, allowing the technologist many alternative simulations in a short time, a 2D slice physical model is chosen and schematically depicted in Figure 2. The deformation for any slice toward the ...

The purpose of the present paper is to predict the grain size of steel during the hot-rolling process. The basis represents a macroscopic simulation system that can cope with temperatures, stresses and strains of steel in a complete continuous rolling mill, including reversible pre-rolling and finishing rolling with several tenths of rolling passes. The grain size models, newly introduced in the present paper, are one-way coupled to the macro-scale calculations performed with the slice model assumption. Macroscale solution is based on a novel radial basis function collocation method. This numerical method is truly meshless by involving the space discretization in arbitrarily distributed nodes without meshing. A new efficient node generation algorithm is implemented in the present paper and demonstrated for irregular domains of the slice as they appear in different rolling passes. Multiple grain size prediction models are considered. Grain size prediction models are based on empirical relations. Austenite grain size at each rolling pass as well as the ferrite grain size at the end of rolling are predicted in this simulation. It is also shown that based on the rolling schedule, it is highly likely that recrystallization takes place at each pass throughout a continuous rolling mill. The simulation system is coded as a user-friendly computer application for industrial use based on programing language C# and an open source developer platform .NET and runs on regular personal computers The computational time for a typical rolling simulation is usually less than one hour and can thus be straightforwardly used to optimize the rolling mill design in a reasonable time.