The vacuum carburizing is characterized by quick saturation
in carbon atoms of the steel surface layer. The release of
the atoms “in statu nascendi” occurs as a result of catalytic
effect of the surface of the steel onto the carburizing atmosphere.
As a result the carbon atoms are being absorbed on the
steel surface and next diffuse into the core. The ability of carburizing
atmosphere to release the carbon atoms as a result of
thermal decomposition of the components of the atmosphere
is very high and so is the carbon potential [2,4,5] at low pressure
carburizing processes. These atmospheres are based on
higher hydrocarbons—mainly acetylene or ethylene or their
mixtures diluted by hydrogen and suite well for carburizing
at low pressure [2,4]. The hydrocarbon decomposition proceeds
in avalanche by means of different chemical reactions,
therefore it is impossible to apply the conventional methods
of process control due to unequilibrium of the processes. This
creates a serious obstacle in prediction of carbon concentration
profile. In order to overcome it, the computer simulation
is being used for the process control at low pressure carburizing.
The work mode of the simulator is based on following