Lipetsk State Technical University (Lipetsk, Russia):

A. G. Levykina, Post-graduate Student
V. N. Soloviev, Cand. Eng., Associate Prof.
I. P. Mazur, Dr. Eng., Prof., Head of Metal Forming Dept., e-mail: mazur@stu.lipetsk.ru

The desire of automakers to reduce the mass of the car while maintaining strength has made the demand for the production of Dual-Phase steels grades. Microstructure of dual-phase steel grades is a ferriticmartensitic structure, the combination of which provides high strength due to martensitic grains and sufficient ductility due to ferritic. However, obtaining a dual-phase structure requires the development of a cooling regime after hot rolling. For this purpose, a mathematical model of the thermal state of the metal on the discharge roller table was developed with a dual-stage strip cooling mode. Mathematical modeling of the thermal state of the metal was performed using the Deform 3D. The spatiotemporal temperature distribution of the metal was described with use non-stationary heat conduction equation with boundary conditions of the second and third kinds depending on the type of heat exchange. The algorithm for calculating dual-stage metal cooling is built on the basis of successive operations, each of which describes a particular boundary condition and contains information about the object under study. The simulation results are presented in the form of graphical dependences of the change in the thermal state of the strip at the reference points with respect to the cooling time on the run-out table. It is shown that an existing installation of accelerated cooling does not provide the required cooling rate for two-stage cooling of the DP-steel. The developed model can be used to study the thermal state of the strip in other known installations the accelerated cooling or after the reconstruction of the existing.
The work was carried out within the framework of the state assignment of the Ministry of Education and Science of Russia under the project No. 11.1446.2017 / 4.6.

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