Galling

Primary Material Parameters. Materials that have limited ductility 

Materials that have a hexagonal close-packed (hep) structure with a high da ratio have a low dislocation cross slip rate and are less prone to galling. This explains why cobalt-base alloys and cadmium-plated alloys resist galling while titanium alloys tend to gall. 

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C7H6O5. Colourless crystals with one molecule of water, m.p. 253" C, sparingly soluble in water and alcohol. It occurs free in woody tissue, in gall-nuts and in tea, and is a constituent of the tannins, from which it can be obtained by fermentation or by acid hydrolysis. It gives a blue-black colour with Fe and is used in the manufacture 6f inks. On heating it gives pyrogallol. 

GALL CLEAN Rl, BC, NCOD, NTOV, MAXDF, MAJCBN)... 

J. E. Gall and co-workers, "Interhalogen Compounds of Fluorine," papers presented m Annual ACS Meeting, New York, Sept. 1947. 

Vegetable-tanning materials in commercial quantities come from many different countries. Quebracho is a principal tanning material from South America. Wattie or Mimosa is suppHed from several African sources. India and other Asian countries supply a variety of materials including Myrabolans, Gall Nuts, and Tara Pods (3). 

Carbon (qv) impregnated with antimony gives a dense nonporous material with a low tendency to seizure or galling which may be useflil in bearings and seals under high loads and velocities at temperatures up to 500 °C (27). 

R.. Gall, in R. G. Rice and. A. Cotmvo, eds., Oc nej Chlorine Dioxide Oxidation Products of Organic Materials Ozone Press International, Cleveland, Ohio, 1978, pp. 356-382. 

H. E. Boyer and T. L. Gall, eds.. Metal Handbook, Desk Edition, American Society for Metals, Metals Park, Ohio, 1985, pp. 4—11. 

Carbon—graphite materials do not gall or weld even when mbbed under excessive load and speed. Early carbon materials contained metal fillers to provide strength and high thermal conductivity, but these desirable properties can now be obtained ia tme carboa—graphite materials that completely eliminate the galling teadeacy and other disadvantages of metals. 

Valve Trim Various alloys are available for valve parts such as seats, disks, and stems which must retain smooth finish For successful operation. The problem in seat materials is fivefold (1) resistance to corrosion by the fluid handled and to oxidation at high temperatures, (2) resistance to erosion by suspended solids in the fluid, (3) prevention of galling (seizure at point of contact) by differences in material or hardness or Both, (4) maintenance of high strength at high temperature, and (5) avoidance of distortion. 

To protect clamping system, use dissimilar metals to prevent galling on threaded fasteners... 

A solution of n-butyll ithium in hexane was obtained from Aldrich Chemical Company, Inc. Before use the solution is titrated with a 1 M solution of 2-butanol in xylene according to the procedure of Watson and Eastham, [see Gall, M. House, H. 0. Ovg. Synth. 1972, 52, 39] with 2,2 -biquinoline as indicator. 

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