Effect of various lubricants and base materials on friction at ultrahigh loads

Effect of various lubricants and base materials on friction at ultrahigh loads

LITERATURE AND CURRENT EVENTS films are used as lubricants. Two methods of substrate preparation for vapor deposition were investigated : (I) mechanic...

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LITERATURE AND CURRENT EVENTS films are used as lubricants. Two methods of substrate preparation for vapor deposition were investigated : (I) mechanical polishing and (z) electron bombardment. Friction experiments were conducted with a hemispherical niobium rider sliding on the deposited gold film on a rotating disk. Results of this investigation indicated that the film endurance life during friction experiments was increased when the substrate was electron bombarded and thermally etched prior to vapor deposition on the etched surface at an elevated temperature of BoooF. A diffusiontype interface was believed to be formed between the film and the substrate. Effect of Various Lubricants and Base Materials on Friction at Ultrahigh Loads. Ii-. E. Demorest and A F. Whitaker, ASLE Trans., q (1966) 160-170. A series of high-load, low-speed slidingfriction tests was made on eight greases and eighteen dry lubricants at normal unit loads from 10,000 p.s.i. to 150,000 p.s.i. Four different substrate materials were used having a range of hardnesses from Rockwell C 18 to Rockwell C 55. The ultimate load capability of both greases and dry films is a fun&ion of substrate hardness with the best ultimate load capability being provided by inorganically-bonded molvbdenum disulfide films with small amounts of graphite added. The coefficient of friction of the greases appears to be an inverse function of substrate hardness and a direct function of the normal load. The coefficient of friction of the dry lubricants is an inverse function of the normal load, but does not appear to be related to the substrate hardness. 3.4. Indr&rial

appldcations

Hydraulic Pump Lubrication in the Presence of Sea Water. A. P. Evans and L. G. Schneider, Lubrication Eng., zr (12) (1965) 518-525; 4 figs., 8 tables, 10 refs. Hydraulic systems of ships are inherently vulnerable to sea water contamination. A successful search was made for a petroleumbase, hydraulic fluid with sufficient rust inhibiting qualities to prevent rusting in submarine hydraulic systems contaminated with 10% sea water. The utility of the emulsifiable fluid was demonstrated by IOOOhours successful operation of a prototype screw pump. Some Examples for the Application of Special Lubricants in Chemical Industry. (in German) W. Stech, Chem-Ing. Tech., 37 (1965) 1248-1252; 3 figs., 2 tables, g refs. The problem of lubrication in a chemical plant can be reduced to two considerations. Either

405 the processed product interferes with the lubricant, or the reverse is the case. Examples are quoted from industrial practice where either a special lubricant or the product itself is used for lubrication, or a lubricant can be dispensed with altogether by resorting to an appropriate structural design of the plant. Evaluation of Vehicle Corrosion Preventives. H. C. Muffley, L&ricatio% Eng., 21(x2) (1965) 506-512; 7 tables, 28 refs. The evaluation of vehicle corrosion preventives revealed seven different basic compositions that could be used for this purpose. A set of requirements and test methods for an acceptable compound are provided. Pollution Abatement and Rolling Mills. H. E. Riester, ~~~~~ca~~~~E?ag., ar (12) (1965) 513-517; I fig. 4. MACHINE

PARTS

4.1. Bearings

and gears

Theorv and De&m Data for Contkuous-f&n, Self-a&g Jo& Bearings. H. G. Elrod. Tr. and S. B. Malanoski, ASLE Trans., 8 (1965) 323-338. Extensions to the theory for the continuousfilm journal bearing are presented. These analyses are used in conjunction with the results of other analyses to provide design data for the complete operating range of a full circular journal bearing. The Externally-pressurized, Porous Wall, Gas-lubricated Journal Bearing. II H. J, Sneck and R. C. Elwell, ASLE Trans., 8 (1965) 339-345. The results of an experimental investigation of an externally-pressurized, porous wall, nonrotating journal bearing that used air as a lubricant are compared with a previously published analysis and found to be in good general agreement, provided the effect of surface roughness is included in the determination of the clearance. Impact Response of a Gas-bearing Supported Rotor. R. A. Burton and H. J. Carper, ASLE Trans., 8 (1965) 346-356. Data are reported for two rotors (I.44 and 5.88 pounds) supported by extemallypressurized gas bearings. Comparative plots show that the effective spring rate for synchronous whirl (a function of pressure) also serves to account for the shaft displacement under gravity load and under low-frequency impact loading. Exceptions are noted at the half-speed whirl threshold and at low speed and low pressure. Some explanation is offered for these discrepancies, as well as for observed displacements somewhat in excess of that Wear, 9 (1966) 398-409