Traditional Nitriding of stainless steel
When Stainless Steel is treated with traditional nitriding, for example in salt bath or plasma, a surface layer is created which consists of a diffusion zone and sometimes also a compound layer. Characteristic to these traditional methods of treatment is the formation of Chromium Nitride (CrN) in this layer, which improves the surface hardness and wear resistance but it is important to note this dramatically reduces the corrosion resistance.
In both the Stainihard® and Stainitec treatments the formation of Chromium Nitride (CrN) or Chromium Carbide (CrC) is suppressed and a so called ‘S-phase’ or ‘Supersaturation phase’ is created.
This layer consists of Stainless Steel which is supersaturated with Nitrogen and / or Carbon at the surface. The saturation creates high internal stresses in the layer and the hardness is increased significantly, without reducing the corrosion resistance. In fact the corrosion resistance is often enhanced also.
Stainihard® is developed to be applied to austenitic stainless steels. In certain circumstances it also is possible to treat other stainless steels (e.g. Duplex or PH stainless steels).
Examples of suited austenitic Stainless Steels :
AISI: 301, 303, 304, 304L, 304Ti, 310, 316, 316L, 316Ti, 321, 347, 904L
DIN-Number: 1.4301, 1.4305, 1.4307, 1.4310, 1.4401, 1.4435, 1.4539, 1.4541, 1.4550