Author(s)

F. Kavicka, J. Dobrovska, K. Stransky, B. Sekanina & J. Stetina

Abstract

The quality of the working rollers from ductile-cast-iron used for rolling rails is determined by the chemical and structural composition of the material of the rollers and the production technology. The requirements of the quality cannot be ensured without perfect knowledge of the course of solidification, cooling and heat treatment of the cast rollers as well as the kinetics of the temperature field of the casting and mould. An original application of ANSYS simulated the forming of the temperature field of the entire system. In the experimental investigation of temperature field, an original methodology for the measurement of the distribution of temperatures and heat flows in the roller-mould system had been developed and verified in the operation. The kinetics of the solidification has a measurable and non-negligible influence on the chemical and structural heterogeneity of the investigated type of ductile-cast-iron. Tying on to the results of the model of the temperature field of the cast rollers, an original methodology was developed for the measurement of chemical microheterogeneity. The structure of this cast-iron is created by a great amount of the transition form of graphite and small amount of globular graphite and also lamellar graphite and cementite, whereas the structure of the metal matrix is perlitic. The chemical and structural heterogeneity of the cast roller is therefore a significant function of the method of melting, modification and inoculation and the successive procedures of risering, casting and crystallization after cooling. Keywords: cast-iron rollers, solidification and cooling, temperature field, numerical model, chemical and structural heterogeneity, measurement.

Keywords

cast-iron rollers, solidification and cooling, temperature field, numerical model, chemical and structural heterogeneity, measurement.