CARBODIFFUSION® is a superficial strengthening of stainless steels, achieved by the diffusion of Carbon in gaseous phase at low temperature, to obtain a massive surface concentration of 5-7% (or 20-25% in volume). Carbon is incorporated into the interstitial cavities of the crystalline structure without the creation of chromium carbides, which would result in lower resistance to corrosion.
CARBODIFFUSION® also generates strong compressive stresses on the surface, which improve the mechanical characteristics of the material, especially fatigue strength. Treatment depth is 22 or 33 μm.
GEOMETRY – MATERIALS
As far as geometry is concerned, the piece in its entirety is treated; sharp edges and blind (and/or small diameter) holes are also hardened. The workpiece does not undergo any deformation and its dimensions remain unchanged.
The non-magnetic properties typical of austenitic steels remain unchanged. The best results are obtained with austenitic and austenitic-ferritic (Duplex) stainless steels: good results are also obtained with certain nickel-based alloys (Inconel®, Hastelloy®). Some martensitic stainless steels are normally treated, but with some limitations.
The treated surface area is totally non-toxic.
Depending on the treatment depth (22 or 33 μm), surface hardness varies from 1000 to 1200 HV 0.05 (> 70 HRC), depending on the treated material. Seizures are completely eliminated and wear resistance is greatly improved. General mechanical properties do not change (for thick parts), while fatigue strength is significantly increased. Sheet_Carbodiffusion.indd 1 16/03/15 23.32 CARBODIFFUSION®
For steels containing Molybdenum and traces of ferrite, resistance to pitting corrosion and stress corrosion is greatly improved. With this coating, delamination and flaking are excluded.
FIELDS OF APPLICATION
The CARBODIFFUSION® process is used to further improve the corrosion resistance of stainless steels (austenitic-martensitic), or to increase or improve abrasion resistance.
The surface hardnesses obtained with this process are around 1000.1300HV. Sectors of application are:
- Shut-off valves, ball valves, etc.
- All types of pumps: piston, lobe, centrifugal, gear pumps, etc.
- Surgical machines and instruments
- Fuel injection pumps, ABS systems
- Chains, rollers, gears, barrels, etc.