VACUUM CARBURISING

Vacuum carburizing is a state-of-the-art thermal process where carburizing is effected under very low pressures. First the parts are heated in vacuum to above the change temperature of the alloy. Then they are exposed to carbon-carrying gas, or gas mixtures, under partial pressure.

Benefits of Vacuum Carburising

  • repeatable results to within ±0.001" (±25µm)
  • significantly reduced size changes and distortion
  • improved fatigue strength
  • better control of the surface layer chemistry
  • the process is environmentally friendly  

Why Vacuum Carburizing Is in Demand.

Only low pressure vacuum carburizing allows the end user to dial in settings for case depth, carbon profiles, surface/core hardness and case/core microstructure. With Low pressure carburizing it makes it very easy to predict distortion results which can then be used to achieve required properties at the lowest unit cost. Conventional materials such as 8620, 8822, 9310, and parts that are traditionally atmosphere carburized can greatly benefit from these techniques. Documented savings in post-machining operations and material stock allowances make the use of vacuum carburizing not only practical, but very financially attractive.

The Future of vacuum carburizing.

Aerospace and automotive specifications need to be reviewed in light of rapid developments underway with these new materials. Serious consideration must be given to the use of elevated temperatures above 1900ºF (1040ºC) for carburizing and direct quenching, to minimize cycle times and reduce carbon absorption without adversely affecting microstructure. Preoxidation treatments have been found to be unnecessary, and rules for the use of high gas pressure quenching need to be better established and realized throughout the industrial sectors. Once this is accomplished, vacuum carburizing technology offers almost limitless possibilities.