• SURFACE ENGINEERING DEVELOPMENTS •
Unlocking new possibilities for stainless steel components
Temitope Oluwafemi, technical manager at Bodycote, explains how new developments in surface engineering are being used to improve stainless steel integrity.
• By Temitope Oluwafemi, Bodycote
Stainless steel remains the material of choice across countless industrial applications, valued for its corrosion resistance, hygiene, and regulatory acceptance. From oil and gas infrastructure to food processing equipment and medical devices, it offers a reliable balance of mechanical performance and environmental resistance that few other materials can match.
However, in many demanding environments, wear, galling, cavitation erosion, and cyclic loading often become the limiting factors in reliability and service intervals. Traditional solutions, such as applying coatings or oversizing components to extend service life, can introduce additional cost, complexity, contamination risk, or reduced corrosion resistance.
Engineers are therefore faced with a dilemma: how to improve overall durability without sacrificing the very properties that made stainless steel the preferred material in the first place.
Why harder can mean weaker Improving durability in stainless steel has never been straightforward. The challenge is not simply increasing hardness but doing so without undermining the alloy’ s corrosion resistance or mechanical integrity.
Many conventional hardening methods rely on elevated temperatures
(> 500 ° C) to alter the surface microstructure. While effective at increasing hardness, such temperatures can change the chemical bonds within the material’ s structure. In stainless steels, chromium is essential for maintaining the protective passive layer that prevents corrosive attacks. When excessive heat is applied, it becomes tied up in carbides or nitrides, making the stainless steel vulnerable to chemical attack.
Coatings and plating offer an alternative route, adding a harder external layer to resist wear. However, coatings behave differently from the underlying substrate. Under load, impact, or cyclic stress, a discrete layer can crack or separate from the base material. In regulated or particle-sensitive environments, this introduces potential contamination risks. Coatings may also influence tolerances, adhesion characteristics, or surface finish requirements.
What engineers need is a means of modifying the material and strengthening the surface performance while preserving the alloy’ s inherent properties. A surface engineering technique developed as part of Bodycote’ s Specialty Stainless Steel Processes( S ³ P) may hold the answer.
Material improvement without compromises S ³ P Austenitic, Duplex, Martensitic( S ³ P ADM) is a low-temperature, diffusion-based surface hardening process developed as part of Bodycote’ s established Specialty Stainless Steel Processes( S ³ P) portfolio. Building on earlier S ³ P technologies, ADM extends controlled diffusion hardening across a wider range of stainless steel families. It enables engineers to extend the performance envelope of corrosion-resistant alloys by significantly improving tribological and mechanical surface behavior, while keeping the base material properties intact.
S ³ P ADM is used to apply controlled carbon or carbon and nitrogen diffusion into austenitic, duplex, and martensitic stainless steels— three alloy families with distinct mechanical and corrosion characteristics. Conducted below 500 ° C, the process enables interstitial diffusion of carbon or carbon and nitrogen into the surface without triggering the precipitation of chromium carbides or nitrides that can degrade corrosion performance. The result is the formation of a hardened diffusion zone, often described as expanded austenite or S-phase, within the surface layer of the material.
36 Stainless Steel World Americas | June 2026 | ssw-americas. com