Low-pressure carburizing with subsequent quenching is a special form of case hardening Compared to case hardening in gas, the benefits of vacuum technology can be exploited by selecting carburizing temperatures of up to 1070 °C. Thus, the duration cycle can be significantly reduced especially for high case hardening depths.
With low-pressure carburizing, the correct carbon profile in the workpiece is adjusted precisely for the respective case hardening depth with alternating carburization and diffusion steps. The batch is then reduced to the hardening temperature and hardened with the help of high pressure gas quenching. Low-pressure carburizing results in a high surface hardness and a ductile core for the workpieces, which are optimum properties for high-stress use in future operations. By selecting acetylene as the carburizing gas and at a very low treatment pressure, the formation of soot, which was previously a problem with this technology, is completely avoided. At the Hanomag hardening plant at the site in Gommern, the low-pressure carburizing process takes place in a single chamber vacuum furnace. The furnace chamber is 910 mm wide. The maximum batch weight is 1,500 kg
Benefits of low-pressure carburizing
- Optimum uniformity for complex component geometries and heavy loading.
- Surface free of oxidation
- Clean and smooth surface finish (blasting not necessary)
- Precise adjustment of case hardening depths from 0.05 mm up to several millimetres.