Whatever Your Stainless Steel Alloy

-There Is Always An Expanite Solution

Expanite® is developed to increase surface hardness and wear resistance of austenitic, martensitic, ferritic and duplex stainless steels as well as nickel-based and cobalt-chromium alloys. Expanite has experience working with many alloys - typical examples are.

Austenitic stainless steel 

201 / 301 / 303 / 304 / 305 / 308 / 310 / 316 / 904

Austenitic stainless steel constitutes one of the five categories of stainless steel categorized by their crystalline structures, which include ferritic, martensitic, duplex, and precipitation-hardened varieties. Its predominant crystalline structure is austenite, characterized by a face-centered cubic arrangement. This inherent structure renders these steels resistant to hardening through heat treatment and imparts them with non-magnetic properties. The establishment of this structure is accomplished by incorporating sufficient austenite-stabilizing elements like nickel, manganese, and nitrogen. The Incoloy alloy family is a subset of the super austenitic stainless steel category. Learn more on WIKI 

Martensitic stainless steel

420 / 440 / 17-4PH / 17-7PH

Martensitic stainless steel represents a specific class of stainless steel alloy characterized by its martensite crystal structure. This type can undergo hardening and tempering processes via aging and heat treatment. The primary alternate categories of stainless steel include austenitic, ferritic, duplex, and precipitation-hardened variants.

Martensitic stainless steels find frequent application based on their carbon content, primarily valued for their corrosion resistance and remarkable strength in applications like pumps, valves, and boat shafts. Additionally, their wear-resistant attributes make them essential in a wide range of uses, including cutlery, medical instruments such as scalpels, razors, and internal clamps, ball bearings, razor blades, injection molds for polymers, and brake discs for bicycles and motorcycles. Learn more on WIKI

Duplex stainless steel

2205 / 2507

Duplex stainless steels constitute a distinct family within the realm of stainless steel. These alloys are dubbed "duplex" or "austenitic-ferritic" grades due to their metallurgical structure, comprised of two phases - austenite (characterized by a face-centered cubic lattice) and ferrite (displaying a body-centered cubic lattice) - present in roughly equal proportions. Their design aims to deliver superior corrosion resistance, specifically against chloride-induced stress corrosion and chloride pitting corrosion, along with elevated strength in comparison to standard austenitic stainless steels like Type 304 or 316.

The primary disparities in composition, when contrasted with austenitic stainless steel, involve higher chromium content (ranging from 20% to 28%), increased molybdenum (up to 5%), reduced nickel (up to 9%), and a nitrogen content between 0.05% and 0.50%. This combination of lower nickel content and enhanced strength, allowing for the use of thinner sections, yields significant cost advantages. Consequently, these alloys find extensive usage in the offshore oil and gas sector for systems like pipework, manifolds, and risers, as well as in the petrochemical industry through pipelines and pressure vessels.

Notably, duplex stainless steels not only boast improved corrosion resistance compared to the 300 series, but they also offer heightened strength. For instance, while a Type 304 stainless steel exhibits a 0.2% proof strength around 280 MPa (41 ksi), a 22%Cr duplex stainless steel features a minimum 0.2% proof strength of approximately 450 MPa (65 ksi), and a superduplex grade boasts a minimum of 550 MPa (80 ksi). Learn more on WIKI

Ferritec stainless steel

430 / 431 / 434

Ferritic stainless steel constitutes one of the five primary families of stainless steel, alongside austenitic, martensitic, duplex stainless steels, and precipitation-hardened varieties. Notably, a significant portion of the AISI 400-series stainless steels belong to the ferritic category. In contrast to austenitic variants, ferritic steels exhibit diminished hardenability through cold working, reduced weldability, and should be avoided for applications involving cryogenic temperatures. However, certain types, such as 430, showcase impressive corrosion resistance and exceptional heat tolerance. Learn more on WIKI.

The purpose of the process! 

ExpaniteHigh-T

The purpose of this process is to dissolve nitrogen in the surface of stainless steel to a depth in the range of 0.2-2 mm. Peak hardness ranges from 280HV on austenitic grades to 950HV on martensitic/ferritic grades.

ExpaniteLow-T

The purpose of this process is to dissolve nitrogen and carbon in the surface of stainless steel to a depth in the range of 5-30µm. Peak hardness ranges from 1000-1200HV on austenitic grades to 1200-1800HV on martensitic/ferritic grades.

SuperExpanite®

The purpose of this process is to combine ExpaniteHigh-T and ExpaniteLow-T processes to achieve higher load bearing and corrosion properties. Firstly, the ExpaniteHigh-T process is applied to create a deep case depth with moderate nitrogen content. Secondly, the ExpaniteLow-T process is applied to create a high-hardness surface on top of the ExpaniteHigh-T zone. The Expanite process does not result in a coating, but a diffusion zone with an increased carbon and nitrogen content. We call this zone expanded austenite, expanded martensite or simply: Expanite.

Expanite® is developed to increase surface hardness and wear resistance of austenitic, martensitic, ferritic and duplex stainless steels as well as nickel-based and cobalt-chromium alloys. Expanite has experience working with many alloys - typical examples are