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Effect of surface coatings on the load carrying capacity of steel
LITERATIJRB
250
ANT, CURRENT
including molybclmum disulphidc, is influenced be- the nature of the base lulrricant and the compstability of the additives. Water in oil has a detrimental effect which ran Ix counteracted by additivrs. lnvestigaadditives,
3. T.uRRrcnrroN A Model Experiment in Elasto-Hydrodynamic Lubrication. G, R. Higginson, Intwz. J. Mpch. Sci., 4 (1962) 205-2’0; A$$. Mpch. Rev., r6 (2) (1963) 173, no. 1310. Fuel and Lubricant Requirements of Modern High Output Two-stroke Cycle Outboard Motors. G. H. Millar and 13. Carlson, Lubrication Eng., 19 (1) (1963) 21~-27; 12 fig., I ref. Effect of Surface Coatings on the Load Carrying Capacity of Steel. G. F. Wolfe, Lubricalion Eng., ry (I) (1963) 28-35; 2 fig., 9 tables, 11 refs. The effect of various surface coatings on improving the load carrying and anti-wear characteristics of steel in silicone, dies&, and petroleum oils is presented. Data were obtained using the Falex machine, a roll tester, and a gear test stand. The surface coatings evaluated included metal plates, banded solid lubricants, flame sprayed coatings, salt bath treatments, and electric spark metal deposition. The resutts indicate that whenever the combination of steel sliding on steel is broken up, an improvement in load carrying capacity and anti-wear properties is obtained. Soft metal pIatcs and metals with low melting points improve the load carrying ability of steel in all oils. Silver plate is very effective. Diffusion processes which produce a definite case layer on steel also provide very satisfactoryseizureandanti-wearproperties. Several processes outperform conventional nitriding and carburizing. The most promising surface coatings should be considered for applications where increased load carrying ability or operation in unusual environments is required. Engineering applications of such coatings will. of course, depend on a full analysis of all the operating conditions as well as the particular characteristics of any specific surface.
EVENTS
tion by radio-active tracer technique has shotvn that accclcrated failure in the prescnct of water- may be due to hydrogen cmbrittll:ment.
AND LrrBRrcaNrs Physical and Chemical Properties of Complex Soap Greases. A. T. l’olishuk, Lz&icration fing., rp (2) (7963) 76.. 87; 16fig., 12 tables, 72 refs. The properties of soap particles and fibers characterize the structure and physical pmperties of their greases. But the chemistry of the soap molecule itself is the most significant factor. It is especially useful in defining complcx soap grcascs. It is suggested that cornl’lex soap greases be defined as those which are formed when two dissimilar acids arr attached to the same molecule. By this definition, only polyvalcnt elements can form true complex soaps. Complex soap greases arc among the best, currently available, multipurpose lubricants. The most commonly used complex greases arc those of calcium and barium soaps, yet they seem to offer little advantage over conventional lithium multipurpose greases. They have higher dropping points, and some calcium complexes offer built-in EP properties, but they have poor reversibility and dispensability characteristics. Barium complexes require high soap contents and are costly. Aluminum complex greases arc the best of the complex greases. They have excellent pumpabilitv characteristics, good mechanical and oxidation stability, and outstanding rcsistance to oil separation when subjcctcd to pressure and/or tcmpcraturc. Wear and Corrosion Tendencies of Molybdenum Disulfide~Contaiuing Greases. S. F. Calhoun, Tech. Rept., (1962) 13 pp., 19 refs., Sci. and Tech. .4crospace Repts., 1 (2) (1963) III. The tendency of molybdenum disulfide to increase the wear of greases is shown by results of laboratory tests. The extreme pressure properties of greases were increased by the addition of the molybdenum disulfide. It also promotes rusting of ferrous metals when added to grease.
4. MACHINE PARTS 4.x Mechanical
ditions
Elements
under Entveme
Con-
MechanicalElementsforVacuumOperation. H. E. Evans, T. W. Flately and M. Francis Federline, Sci. and Tech. Aerospace Rep&., I (3) (1963) 182. N 63-11278, NASA;Presented at the ARS 17th Ann. Meeting and Space
Flight Exposition, Los Angeles, Nov. 13-18, 1962 ; (ARS Paper 2711-62) 12 pp. The first two phases of a program investigating the high-speed operation of miniature ball bearings with metallic film lubrication and the first phase of an investigation for determining the “best bet” gear material combinations
250
ANT, CURRENT
including molybclmum disulphidc, is influenced be- the nature of the base lulrricant and the compstability of the additives. Water in oil has a detrimental effect which ran Ix counteracted by additivrs. lnvestigaadditives,
3. T.uRRrcnrroN A Model Experiment in Elasto-Hydrodynamic Lubrication. G, R. Higginson, Intwz. J. Mpch. Sci., 4 (1962) 205-2’0; A$$. Mpch. Rev., r6 (2) (1963) 173, no. 1310. Fuel and Lubricant Requirements of Modern High Output Two-stroke Cycle Outboard Motors. G. H. Millar and 13. Carlson, Lubrication Eng., 19 (1) (1963) 21~-27; 12 fig., I ref. Effect of Surface Coatings on the Load Carrying Capacity of Steel. G. F. Wolfe, Lubricalion Eng., ry (I) (1963) 28-35; 2 fig., 9 tables, 11 refs. The effect of various surface coatings on improving the load carrying and anti-wear characteristics of steel in silicone, dies&, and petroleum oils is presented. Data were obtained using the Falex machine, a roll tester, and a gear test stand. The surface coatings evaluated included metal plates, banded solid lubricants, flame sprayed coatings, salt bath treatments, and electric spark metal deposition. The resutts indicate that whenever the combination of steel sliding on steel is broken up, an improvement in load carrying capacity and anti-wear properties is obtained. Soft metal pIatcs and metals with low melting points improve the load carrying ability of steel in all oils. Silver plate is very effective. Diffusion processes which produce a definite case layer on steel also provide very satisfactoryseizureandanti-wearproperties. Several processes outperform conventional nitriding and carburizing. The most promising surface coatings should be considered for applications where increased load carrying ability or operation in unusual environments is required. Engineering applications of such coatings will. of course, depend on a full analysis of all the operating conditions as well as the particular characteristics of any specific surface.
EVENTS
tion by radio-active tracer technique has shotvn that accclcrated failure in the prescnct of water- may be due to hydrogen cmbrittll:ment.
AND LrrBRrcaNrs Physical and Chemical Properties of Complex Soap Greases. A. T. l’olishuk, Lz&icration fing., rp (2) (7963) 76.. 87; 16fig., 12 tables, 72 refs. The properties of soap particles and fibers characterize the structure and physical pmperties of their greases. But the chemistry of the soap molecule itself is the most significant factor. It is especially useful in defining complcx soap grcascs. It is suggested that cornl’lex soap greases be defined as those which are formed when two dissimilar acids arr attached to the same molecule. By this definition, only polyvalcnt elements can form true complex soaps. Complex soap greases arc among the best, currently available, multipurpose lubricants. The most commonly used complex greases arc those of calcium and barium soaps, yet they seem to offer little advantage over conventional lithium multipurpose greases. They have higher dropping points, and some calcium complexes offer built-in EP properties, but they have poor reversibility and dispensability characteristics. Barium complexes require high soap contents and are costly. Aluminum complex greases arc the best of the complex greases. They have excellent pumpabilitv characteristics, good mechanical and oxidation stability, and outstanding rcsistance to oil separation when subjcctcd to pressure and/or tcmpcraturc. Wear and Corrosion Tendencies of Molybdenum Disulfide~Contaiuing Greases. S. F. Calhoun, Tech. Rept., (1962) 13 pp., 19 refs., Sci. and Tech. .4crospace Repts., 1 (2) (1963) III. The tendency of molybdenum disulfide to increase the wear of greases is shown by results of laboratory tests. The extreme pressure properties of greases were increased by the addition of the molybdenum disulfide. It also promotes rusting of ferrous metals when added to grease.
4. MACHINE PARTS 4.x Mechanical
ditions
Elements
under Entveme
Con-
MechanicalElementsforVacuumOperation. H. E. Evans, T. W. Flately and M. Francis Federline, Sci. and Tech. Aerospace Rep&., I (3) (1963) 182. N 63-11278, NASA;Presented at the ARS 17th Ann. Meeting and Space
Flight Exposition, Los Angeles, Nov. 13-18, 1962 ; (ARS Paper 2711-62) 12 pp. The first two phases of a program investigating the high-speed operation of miniature ball bearings with metallic film lubrication and the first phase of an investigation for determining the “best bet” gear material combinations