Surface Hardening of Stainless Steel

Game-changing Sustainable Technology

Surface hardening of stainless steel is a heat treatment technique that only very few companies master and nobody does it like Expanite. Expanite’s patented and proven technology, scientific know-how and flexible delivery model significantly improves product performance, quality and reduces costs.

The Expanite hardening processes effectively removes the oxide layer protecting stainless steels. This allows for controlled diffusion of nitrogen and/or carbon atoms in the underlying metal. The hardened layer is characterized by an expansion of the material structure. We call this zone expanded austenite, expanded martensite or simply, Expanite®.


Sustainability Might Be a Choice, But With Expanite It´s a Given! 

Since the foundation of the company sustainability has been close to the hearts of the founders. Not only is the sole purpose of the treatments aiming at extending lifetime of components and systems, the “path” to achieve this life-extending state is more sustainable compared to alternative/competitive products: the ultra-short processing times yielding lowest possible carbon footprint, the lack of chemicals used before & after processing, and the non-toxic-waste processing are all core elements of Expanite’s technology, not a choice!


The individual processes are referred to as SuperExpanite, ExpaniteLow-T and ExpaniteHigh-T – and each of these processes comes in standard versions or tailored. However, the key is that no matter the stainless steel alloy - austenitic, martensitic, ferritic or duplex grades - there is an Expanite solution.

And the outcome is a significant improvement in wear and galling resistance due to a surface hardness of approx. 700-1300HV, and typically maintained or even improved corrosion resistance. Expanite processes are running daily, resulting in lead-times significantly lower than alternatives and full flexibility in when parts can be delivered for processing.

For those already using some sort of wear or galling prevention, Expanite’s surface hardening of stainless steel can be used for:

  • Replacing coatings such as hard-chrome plating for environmental and cost reasons, or PVD/DLC for cost or “line-of-sight” reasons
  • Replacing traditional low-temperature carburizing diffusion processes for environmental, cost, corrosion resistance or lead-time reasons
  • Replacing conventional heat treatment on martensitic steels to improve wear and corrosion resistance

Introduction to Stainless Steel 

Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 12% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's resistance to corrosion results from the chromium, which forms a passive film that can protect the material and self-heal in the presence of oxygen

The resistance to corrosion and luster are used in many applications. Stainless steel can be rolled into sheets, plates, bars, wire, and tubing. These can be used in cookware, cutlery, surgical instruments, major appliances, vehicles, construction material in large buildings, industrial equipment (e.g., in paper mills, chemical plants, water treatment), and storage tanks and tankers for chemicals and food products.

The biological cleanability of stainless steel is superior to both aluminium and copper, having a biological cleanability comparable to glass. Its cleanability, strength, and corrosion resistance have prompted the use of stainless steel in pharmaceutical and food processing plants.

Different types of stainless steel are labeled with an AISI three-digit number, The ISO 15510 standard lists the chemical compositions of stainless steels of the specifications in existing ISO, ASTM, EN, JIS, and GB standards in a useful interchange table. 

Don´t Just Take Our Word for It! 

Expanite has conducted several certified ASTM and/or ISO tests to document wear, galling and corrosion resistance click below for more:


 Replacement for DLC coating  Replacement for DLC coating  Replacement for DLC coating

 Replacement for DLC coating  Replacement for DLC coating