Numerical modeling of temperature and structural states of bimetallic rolls during surfacing

The production of high-strength cold rolls is an extremely important problem. Therefore, the development of numerical methods for the analysis of temperature and structural states of bimetallic rolls during surfacing is relevant as it allows rationalizing the technological processes of their manufacturing. In this paper, a mathematical model describing the temperature field and the structure distribution in the roll during the entire process of surfacing is developed. The solution of a nonlinear non-stationary heat conduction problem is based on the finite element method. Boundary conditions of the third kind are used to describe the heat conduction. The Avrahami equation forms the basis for simulating the transfor mation of austenite into pearlite under isothermal conditions. Changing from the isothermal decomposition kinetics of austenite to nonisothermal conditions is described by the theory of isokinetic reactions involving the additivity rule. The results of calculation of temperatures and structures in a bimetallic cold roll are presented for various moments of surfacing. It is shown that the roll spindle made of 60HN steel saves its pearlitic state after surfacing. The build-up layer of 25N12M6K10 steel with carbide intermetallic hardening has a martensitic structure after cooling the roll. The developed software can be used for predicting the stress-strain state and strength of the roll after surfacing.

References

[1] Tsvetkov F.F., Grigor’ev B.A. Teplomassoobmen [Heat and Mass Transfer]. Moscow, Moscow Power Engineering Institute publ., 2006. 550 p.

[2] Vafin R.K., Pokrovskii A.M., Leshkovtsev V.G. Prochnost’ termoobrabatyvaemykh prokatnykh valkov [Strength heat-treatable mill rolls]. Moscow, Bauman Press, 2004. 264 p.

[3] Pokrovskii A.M., Polushin A.A. Raschet termonapriazhenii v stal’nykh prokatnykh valkakh pri induktsionnoi zakalke TPCh [Calculation of thermal stresses in the steel mill rolls during induction hardening TFC]. Proizvodstvo prokata [Rolled Products Manufacturing]. 2009, no. 5, pp. 32–40.

[4] Christian J.W. The Theory of Transformations in Metals and Alloys. Parts I. Oxford, Pergamon, 2002. 1200 p.

[5] Pokrovskii A.M. Raschet termonapriazhenii pri elektronormalizatsii kompozitnykh prokatnykh valkov [Calculation of thermal stresses at elektronormalizatsii composite mill rolls]. Proizvodstvo prokata [Rolled Products Manufacturing]. 2007, no. 9, pp. 39–45.

[6] Demmel’ D. Vychislitel’naia lineinaia algebra: teoriia i prilozheniia [Computational linear algebra: theory and applications]. Moscow, Mir publ., 2001. 429 p.

[7] Materialovedenie [Materials Science]. Ed. Arzamasov B.N., Mukhin G.G. Moscow, Bauman Press, 2008. 648 p.

[8] Pokrovskii A.M. Raschet ostatochnykh napriazhenii v bimetallicheskikh opornykh prokatnykh valkakh posle termicheskoi obrabotki [Calculation of residual stresses in the bimetallic support rollers rolling after heat treatment]. Vestnik MGTU im. N.E. Baumana. Ser. Mashinostroenie [Herald of the Bauman Moscow State Technical University. Mechanical Engineering]. Special issue no. 6 «Recent developments in applied mechanics, dynamics and strength of machines», 2012, pp. 186–196.