As steam it can hold extremely high temperatures. It is called super heated steam.
I think that somebody wrote something or another 'bout some cheshire cat (waht I now - I'm merely self taught). Hey, I'm trying to promote some image here (so bear with me even if its not workin').
"Latent Heat of Vaporization", look it up and scratch your head a little.
Heat added to Saturated steam (at a given pressure)does nothing to raise the temp of the steam. It merely transfers more steam to a superheated (Dry Steam/No Water Vapor)) state. Only then can heat be added to increase temp.
As an example this would take place in a power plant. Superheated steam would be sent through the High Pressure stage of the turbine where Temp. and pressure is (Used)reduced.
The Superheated steam would then be sent back to the Boiler to a Reheat section. Exhaust/Flue Gases would be used to raise the Temp. of the steam but not the pressure. There would actually be a pressure drop due to piping. Then back to the Turbine through a Intermediate pressure section and then a Low pressure section.
The Temp. increase that takes place in the reheat section contributes to the Enthalpy equation.
Already paid for (Obtained from Flue Gas) these temps. are essential to efficient operations. They really do mean the top end for the plant.