| abstract |
The cementation process according to the invention consists in bringing the parts to be treated to a temperature between 800 ° C and 1100 ° C, preferably higher than 900 ° C, in a gaseous atmosphere free of oxygen maintained by pumping at a pressure between 1 and 5 mbar, and carrying out a plurality of successive carbon enrichment phases (C₁, C₂) each obtained by an injection of limited duration, of a treatment gas comprising one or more pure hydrocarbons, each phase enrichment (C₁, C₂) having a duration less than the time of transition to the saturation phase of the austenite, these enrichment phases being separated by vacuum diffusion phases (D₁, D₂) of greater duration allowing d '' adjust the surface carbon content.n n n The invention simplifies the carbon transfer mechanism and avoids the harmful effects of overfilling. |