Expanite has recently developed surface hardening solutions for the pump and valve market. The main problems in these industries often involve wear and galling all applications where either metal sealing is needed, or due to high operational temperatures (far above 300 °C) and/or corrosive environments, conventional coatings and most non-metallic bushings cannot be used.
Even where special coatings may be applied in certain environments, heating and cooling cycles normally introduce a high risk of spallation due to different coefficients of thermal expansion.
Expanites technology has set a new standard for wear and galling on different materials such as conventional stainless steel (1.4404/AISI 316, Duplex 1.4462, Nitronic, 1.4980/Alloy A-286), Ni-based alloys (e.g. Monel® K500, Inconel® 718 and Hastelloy®) and Co-based alloys such as Stellite®. 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.
Expanites hardening technology generates surface hardness values in the area of 900 to 1500 HV on stainless steel, Co-based and many Ni-based alloys, thereby effectively preventing galling. 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.
Applying the Expanite-technology on these shafts prevents galling and thereby increasing the lifetime of the valve components.
Image courtesy of Expanite