The Effects Of Low Temperature Carbon Diffusion On Stainless Steel

Stainless steels along with Nickel based alloys are often selected for many applications in corrosive environments. While resistance to corrosion makes them a favorable choice, poor tribological behavior may prevent a broader use of these materials.

Kolsterising® is a low temperature carbon diffusion treatment for stainless steel that can expand the design window of these alloys. This diffusion process results in a significant increase in surface hardness while still maintaining the ductility and corrosion resistance of the substrate. It is a proprietary, thermochemical diffusion process that forms a carbon S-phase at the surface while avoiding carbide precipitation which causes sensitization.

Due to the addition of large concentrations of carbon atoms, high compressive stresses are formed at the surface. These compressive stresses along with occupation of the interstitial sites by carbon atoms cause an increase in the surface hardness of the material and improved mechanical properties without
altering part dimensions.

The purpose of this discussion is to provide an introduction to Kolsterising® and review the mechanical benefits on galling behavior, wear resistance, cavitation erosion, and fatigue strength.