Metallurgy, high vacuum

Bearings and sealing Ball bearings especially for high speed high stiffness applications No or low lubrication (vacuum pumps, dental drill handpieces) Under corrosive conditions (food ndustry chemistry metallurgy) high and low temperatures... 

Materials with a low o rgen content are best subjected to a preliminary homogenization treatment, either by high-frequency heating in high vacuum, or by so-called button-melting in an electric arc, which is familiar in titanium metallurgy. 

USE In ferrous metallurgy Ferroniobhim (produced by silicon reduction of columbite) is used to alloy stainless steels and metals for welding rods. In niobium base alloys lor high temps and nuclear reactions. Niobium has some use as a getter in electronic vacuum tubes. 

USE Powerful reducing agent in acid solution or at high temps hydrogenation catalyst in the vacuum tube industry and powder metallurgy. 

Use of smooth high alloy tubes in otherwise corrosive service has been common practice since the 1950s. Tube metallurgy is selected to minimize corrosion while in service. The tubes therefore maintain their smooth, shiny finish. Without sites for fouling deposits to attach or accumulate, the clean heat-transfer coefficient is maintained. This idea has been used with success in refinery catalytic cracker feed preheat service, placing slurry oil on the tube side and vacuum gas oil on the shell side. 

The high-temperature plasma technology (PLASMOX process) is used in metallurgy and plays an important part in the production of titanium alloys. The vacuum melting procedure used for compaction of radioactive waste is also based on plasma technology. 

Vacuum arc remelting (VAR) (metallurgy) The melting of an alloy by a low voltage, high current arc in a vacuum (10 mbar). See also E-beam melting Vacuum-induction melting. 

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