I fully agree with Tom on the distortion bit. I also seriously question the "Fact" that Cyanide will result in a higher hardness that pack hardening. "Carburizing" is simply the part which adds carbon to the skin (Case) of the steel. The carburizing only minimally hardens it if at all, the quench hardens it. A part can definitely be carburized deeper than .003" by the pack carburizing method.
They can be "Colored" by heating below the critical temp, but they are then not hardened as Tom said. When the critical temp is passed the molecules are re-arranged, the sudden quenching "Locks" them into this new arrangement. If allowed to cool slowly they revert to their original condition, this is what annealing does.
