Simulation systems used for many years in foundry industry such as MAGMASOFT, NovaFlow&Solid and ProCAST, contain thermo-mechanical modules permitting the estimation of mechanical stresses and hot tears appearing in casting during its cooling. It is also known that these modules are rarely used because of the very limited thermo-mechanical database especially for ceramic materials such as foundry sand moulds. These technologies – castings pouring in non-permanent sand moulds, particularly iron alloys are most often applied in foundry. In our study the method of evaluating the algorithms quality applied in thermo-mechanical phenomena models based on parameters sensitivity testing from the proper database of the simulation system was used . The comparative analyses of both experimental and virtual results were realized (by stress estimation). The methodology of experimental research was similar to that described where gray cast iron castings of stress bars (grid) were casted in sand mould bonded by organic resins.