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Low pressure carburisation

Low pressure carburisation

Low pressure carburisation with subsequent quenching is a form of case hardening. In contrast with case hardening in gas, it is possible to select carburisation temperatures of up to 1,070 °C thanks to the benefits offered by vacuum technology. This results in a considerable reduction in the cycle time, particularly for high case hardening depths.

With low-pressure carburisation the correct carbon profile is set in the tool for surface hardening depths of approx. 0.60 mm with two carburisation and two diffusion steps. The batch is then reduced to the hardening temperature and hardened with the help of low pressure quenching.

At Hanomag Lohnhärterei group low pressure carburisation takes place in a single-chamber vacuum furnace at the Gommern plant. The furnace chamber is 910 mm wide, 1,220 mm long and 910 mm. The maximum batch weight is 1,500 kg.

Case hardening gives the tools optimal properties for the subsequent stresses during application through a combination of surface hardness and a tough core. The build-up of soot that was a problem in the past with this technology is avoided totally by selecting acetylene as the carburisation gas and a very low handling pressure.


Suitable materials

All case hardened steels (e.g. 16MnCr5, 20MnCr5, 18CrNiMo7-6, 18CrNi8)

Also austenitic steels (e.g. X5CrNi18-10)


Advantages of low pressure carburisation

  • High economic efficiency thanks to shorter processing times
  • Optimal uniformity also for the most complicated component geometry and heaviest loading
  • Surface free from edge oxidisation
  • Clean surface quality free from any coating
  • Accurate setting of the case hardening depths 0.05 mm up to several millimetres
  • High availability of the system technology
  • Carburisation of passive steels is possible
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