Surface engineering since 1992
Surface hardening for stainless components where wear, galling, corrosion behaviour and dimensional control must be considered together. Patt develops S-phase and expanded-martensite treatments around the alloy, prior heat treatment and actual service environment.
Low-temperature plasma nitriding introduces nitrogen while limiting the formation of chromium nitrides that can reduce corrosion resistance. In austenitic stainless steels, the nitrogen-enriched structure is expanded austenite, often called S-phase. In martensitic and precipitation-hardening stainless steels, the corresponding treatment route targets expanded martensite.
These material families need different process settings. Temperature and duration are selected together with surface activation, alloy chemistry and the previous aging or tempering condition. Layer depth, core response and corrosion requirements are reviewed as a combined specification.
| Material family | Application and process focus |
|---|---|
| Austenitic stainless steels, including 304 and 316L | S-phase treatment for sliding surfaces, sleeves, valves and other parts requiring wear and galling control. |
| Martensitic and PH stainless steels, including Patt steels | Alloy-specific expanded-martensite routes for dies, adapters, breaker plates and precision wear parts. |
| Inconel and titanium | Also treated by Patt, with separate alloy-specific process development; their treatments are not described as stainless S-phase. |
The photograph shows a stainless strand die treated by low-temperature nitriding at Patt. Flow passages, die-face condition, cleaning exposure and mating surfaces are considered alongside surface hardness. Machining and surface treatment can be coordinated within the same project.
Send the exact alloy, heat-treatment history, core hardness, drawing, masking areas and contact conditions. Describe the polymer or fluid, operating and cleaning temperatures, and any corrosive exposure. Agree on required depth, surface finish, dimensional checks and corrosion acceptance testing where corrosion performance is central to the application.
Compare nitriding treatments
Diffusion depth, stainless surface hardening and compound-layer design address different contact demands.
A supporting diffusion case for abrasive wear, sliding contact and fatigue resistance. Suited to H13, H11, nitriding steels and suitable quenched-and-tempered alloy steels. Case depth and compound-layer thickness are selected around the core hardness and loading.
ExploreA controlled iron-nitride surface layer for adhesive wear, scuffing and sliding contact. Gamma-prime, epsilon or mixed layers are selected with supporting diffusion depth. Typical materials include carbon and low-alloy steels, nitriding steels and selected tool steels.
ExploreSend the alloy designation, previous heat treatment and core hardness, drawing or dimensions, quantity, areas to treat or mask, and operating conditions. Include the wear or failure problem, target case depth and surface hardness if specified, final tolerances and required delivery date.