Expanite has recently developed surface hardening solutions for the pump and valve market. The main problems in the past in these industries have always been 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. Expanite’s unique diffusion-based hardening technology is applicable to most commercially available corrosion-resistant alloys.
Expanite’s 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 made of Inconel and Monel has previously caused severe problems.
Applying the Expanite-technology on these shafts prevents galling thereby increasing the life-time of the valve components.