Examples from literature

• Furnace annealing is much better and consists in heating the piece in a furnace to the critical temperature and then allowing the work and the furnace to cool together. 
• Here, too, there were no seas, for the temperature was above the critical temperature of water, and only in the self-cooling bodies of these men and in the trees which similarly cooled themselves, could there be liquid. 
• Its critical temperatures will be located at slightly different heats than for a steel which has a different proportion of alloying elements. 
• The critical temperatures are the proper ones for annealing as well as hardening.