Nickel-Based Alloys

Monel® & Inconel®

Expanite provides various surface hardening solutions for case hardening different products in Inconel and Monel achieving a surface hardness of approx. 1000HV on Inconel 718 while the outcome on Monel K500 is approx. 500HV.

Even where special coatings may be applied in certain environments, heating and cooling cycles normally introduce a high risk of spallation due to different co-efficients of thermal expansion. The unique diffusion-based hardening technology of Expanite is applicable to conventional stainless steel (1.4404/AISI 316, Duplex 1.4462, Nitronic, 1.4980/Alloy A-286), Nibased alloys (e.g. Monel® K500, Inconel® 718 and Hastelloy®) and Co-based alloys such as Stellite®.

The technology is proven to improve product performance while getting greater wear and corrosion resistance and extend lifetime of parts compared to other solutions.

Stainless steel is, in many cases, used in valves for food and pharma applications, whereas Monel & Inconel are widely applied in chemically aggressive and harsh environments. Especially on relatively large valves used in the chemical industry and power plants, galling on shifting shafts (opening and closing the valve) made of Inconel and Monel has previously caused severe problems.

Just as with stainless steel, surface hardening of nickel-based alloys is a highly specialized heat treatment process mastered by very few. At Expanite, we have developed a patented and proven technology that combines deep scientific know-how with a flexible delivery model – resulting in improved product performance, consistent quality, and reduced overall costs.

During the Expanite® process, the natural oxide layer on the alloy surface is carefully removed, enabling a controlled diffusion of nitrogen and carbon into the underlying metal. This creates a hardened zone characterized by an expanded material structure – known in metallurgical terms as expanded austenite, and at Expanite simply referred to as Expanite®.