The curie temperature is a temperature which above it the magnetization of ferrite/martensite disappears in steel, how we can calculate this temperature via thermo-calc software?
Typically the magnetic contributions to Gibbs energy are contained as heat capacity contribution of a given phase, although strictly speaking, you have a phase transition. Therefore, you will usually not see a transition line alpha-beta iron, for example. It is (usually) just treated as the same phase. However, you can in principle calculate the heat capacity of the phase under consideration and you will see the Curie temperature by the typical shape of Cp. However: this is only the case if the info about the magentic Cp is contained in the database. In many databases for intermediate phases the contributions from magnetic ordering to the Gibbs energy is not explcitly modeled (due to a lack of good data, or because the effects are considered to be small, and for many solid solutions you have to find out whether the composition dependence of the magnetic behaviour has been modeled. Don't simply believe what the database tells you, because you often do not know how it has been designed.
Real thermocalc experts: please correct me, if I am wrong, or if something important is to be added!
Dear Pedram, here is my case: inside poly-3 after all the declarations and calculations I used the command "show TC(phase)". But take care with the results, because there are several models (as Curie Weiss, Molecular Field and so on) to determine such temperature and, as Prof. Leineweber wrote, we don't know how this transition temperature is considered in each database inside Thermocalc.