In many metallurgical processes, the residual moisture of plant-specific operating materials and lubricants is of central importance. Metallic components, which must have a special quality, are refined in special oil baths in so-called hardening shops. To ensure perfect material quality and to prevent evaporation explosions, moisture sensors are installed directly in the hardening oil and measure the dissolved water content there.

Another area of application is mining and construction vehicles, where moisture in oil monitoring prevents premature wear in gear and engine oils.