We continue our discussion from last time.

Process-Gas Generation

Process-gas generation is extremely critical to the success of the carburizing process. The choices of process-gas generation will depend on:

  • Process economics
  • Equipment availability
  • Natural gas and air generation with enrichment-gas additives
  • Synthesized atmospheres
  • Low-pressure carburizing with enrichment gases
  • Endothermic gas generation
  • Nitrogen-methanol systems

Be particularly attentive to the endo-gas generator. Many companies will run the generator for extended periods of time without what is known as regeneration or burnout. The nickel-oxide catalyst acts in the same manner as a sponge soaks up water. In this instance, the catalyst soaks up excess carbon from the incoming feedstock gas. The carbon must be burned out of a saturated nickel catalyst. It is a simple but very necessary procedure.

If you have only one generator and it goes down for whatever reason, it is unlikely that you will be able to heat treat your gears. The frequent burnout is mandatory, necessary and a required maintenance procedure.

The carburizing process has reached the level of a well-controlled scientific method of surface treatment. This level of science is necessary for the success of the gear design to be both functional and ensure the life of the gear under its performance environment.

The reduction of contact damage to the tooth profile is dependent on three things: gear design, control of the thermal process and material selection.

How do you reduce the risk of contact damage? There is not one single answer to this question. The reduction of the risk of contact damage will be dependent on a better understanding of the engineering science of contact damage in relation to the material selection and the metallurgical process control and evaluation.