The article presents main assumptions of the methodology of integrated modeling of hightemperature steel processing in the aspect of supporting the design of new technologies. The developed solution uses a methodological research capability of modern Gleeble thermomechanical simulators to simulate physical processes, and the benefits of numerical modeling. This allows for restricting the number of expensive experimental tests to the minimum, e.g. by selecting a suitable heating schedule to achieve the desired temperature at the sample section, or getting additional information about the process, eg. estimating the zones with diversified grain growth dynamics, information on local cooling rates at any point within the volume of the sample tested. Mathematical models are original solutions of the developed methodology, such as the thermomechanical model of steel deformation in the semi-solid state, and the multi-scale model of resistance heating coupled with grain growth modelling in the micro scale. The work is supplemented with the main assumptions of the developed mathematical models together with examples of their practical use to support physical simulations.