Please describe the level of detail you need in the simulation and the level of effort and access to resources you have to build this simulation.  To do any simulation you need access to material properties.  What material properties do you have?

The simplest model would not simulate the conversion of the coating into a foam, it would simply start with the final thickness of the foam. A single thermal material property, the conductivity of the foam is all that is needed to compute the temperature vs time of the steel inside the foam for a known surface temperature of the foam. Is this good enough? If so, you can do that in a Steady-State Thermal analysis in Workbench. 

A very complex model would simulate the creation of the foam as the surface temperature rises.  Do you need this level of complexity?