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oil film thickness and rolling friction in elasto-hydrodynamic point contact
SYSTEMATIC ABSTRACTS OF CURRENT LITERATURE The interaction between a machined surface and an abrasive material was analysed in the framework of concepts of electron exchange between their atoms. With several combinations of solids the extent of interaction between them is lowest when the electron exchange does not lead to the formulation of energetically stable states by the interacting atoms and when the majority of nonlocal&xl electrons remains in a free state and forms a specific electron lubricant which prevents interaction. The results of the analysis were verified with the selection of abrasive materials for grinding titanium alloys. Friction in Ball Bearings at Sub-zero Temperatures. A. A. Lyakh, Russian Eng, J., 51 (7) (1971) 50-52; 4figs., 2 tables, 3 refs. (Transl. by P.E.R.A. of Gt. Britain of Vestn. Mashostr., 51 (7) (1971)48-50.) Results are presented of a study of the dependence of the kinematic frictional torque on temperature and load of bearings oil and solid-lubricant lubricated. An empirical formula is derived for the temperature dependence of the frictional torque with various radial loads. Determination of the Coefficient of Friction when Cold-Rolling CopperStrip. B. J. Meadows and G. W. Drinkwater, Met. Meral Forming, 38 (10) (1971) 287-289; 1 tig., 2 tables, 18 refs. The coefficient of friction in cold rolling was obtained by use of the theoretical empirical approach to rolling schedules postulated by Cook and Parker. Experimental and computed rolling schedules are established and maximum utilisation of rolling facilities obtained by using a predetermined constant load.
407
Speed and the condition of the carrier at the moment of deformation were found to be the variables that determined the relative performance of forging lubricants. The Hydrodynamic Lubrication of Rough Bearing Surfaces of Finite Width. H. Christensen and K. Tonder, JOLT, Ser. F 93 (3) (1971) 324-330; 9 tigs., 15 refs. A theoretical analysis of the effects of surface roughness in a finite width bearing based on a stochastic theory of hydrodynamic iubrication. The effect of surface roughness on the bearing characteristics is limited with features of nominal geometry and operating factors. Fluid Rheuiogical Effecta in Sliding Satyrdynamic Point Contacts with Transient Loading: Traction. D. M. Sanbom and W. 0. Winer, JOLT, Ser. F 93 (3) (1971) 342-348; 7 figs., 1 table, 17 refs. Traction values experimentally obtained under the conditions investigated appear to be primarily a function of the sliding velocity. Large variations in fluid composition and inlet viscosity had little influence on the tractive force; rapid application of the normal load had a negligible effect. Optical Analysis of Ball Bearing Starvation. L. D. Wederen, D. Evans and A. Cameron, JOLT, Ser F 93 (3) (1971) 349-363; 24 figs., 2 tables, 29
3.1. Lubrication
refs. Experimental oil tihn measurements obtained by optical interferometry for rolling point contact under starvation conditions illustrates the starvation phenomenon and agrees with theoretical predictions. Starvation inhibits the generation of pressure and reduces film thickness, causes overall pressure, stress and elastic deformation to become more Hertxian. Experiments using interferometry illustrate the cavitation pattern, lubricant entrap ment, grease lubrication, ball spin and edge effects in line contact.
Speed Effects in Forging tibrication. P. W. Waliace and J. A. Schey, JOLT, Ser. F 93 (3)(1971)317-323;1lligs.,22refs. The effect of forging speed on the efficiency of solid and liquid lubricants on the axial upsetting of C steel cylinders and rings was investigated. Increasing speed reduced friction both unlubricated and with lubricants which formed a hydrodynamic film. Carrier fluids with solid lubricants were effective when contact time was short enough to prevent evaporation; residues of a mineral oil carrier impaired the effectiveness of graphite.
Oil F&n Thickness and Rolling Friction in ElaatoHydrodynamicPoint Contact. R. Gohar, JOLT, Ser. F 93 (3) (1971) 371-382; 16 figs., 25 refs. Using a rolling ball and plate machine the effect of material properties on the Blm thickness in point contact is demonstrated. The oil film measured by inte~eromet~ shows no significant alteration over a wide range of Young’s modulus and high pressure and is insensitive to the choice of boundary materials. The rolling friction between
3.
LUBRICATION AND LUBRICANTS
Wear, 21(1972)
408
SYSTEMATIC
ABSTRACTS
OF CURRENT
LITERATURE
a tungsten carbide ball and a glass plate is determined and compared with theory. The effect of spin is found to be slight.
polyether fluid at 500”R and the oil at 305”R therefore no derating of SAE 52100 steel with the polyether at low temperature is necessary.
Oil Lubrication of Rolling Bearings. R.Hobbs, Tribology,4(4)(1971) 198-204; 11 figs., 10 refs. A method of selecting suitable grades of oil is suggested and methods of lubricating oil application are described. Operating characteristics are discussed and some limitations of bearing performance are given.
The Starting Torques and Rheology of Lubricating Greases at Low Temperatures. E. Thelen, M. .I. Devine and L. J. Stalhngs, Lubrication Eng., 27 (9) (1971) 305-310; 7 figs., 3 tables, 13 refs. A study of yield pressure, starting torque and consistency values of lubricating greases at low temperature. Experiments were conducted aimed at relating low-temperature torque to other grease properties. Log torque for a typical grease decreased linearly with log time for 10 to 40 min then abruptly the curve becomes more precipitous and a new linear segment is produced. After 1040 min at the new increased slope, equilibrium is reached and the torque abruptly ceases to change with time; 9 of 19 greases tested followed this pattern. Among the other 10 greases 5 variations of this pattern were displayed.
A Thermodynamic Method of Bearing Analysis. A. Nica, Tribology, 4 (4) (1971) 218-226; 13 figs., 24 refs. The coupled Reynolds and energy equations are considered for both thrust and journal bearings. The one dimensional solutions arc provided with correction coefficients depending on the actual bearing width, resulting in ready for use relations. Diagrams obtained by numerical treatment are presented for finite bearings, besides the analytical relations for actual design arrangements. Comparisons with experimental results are satisfactory.
3.2. Liquid Lubricants Oxygen-containing Cutting Fluids Increase Tool Life. V. N. Latyshev, Russian Eng. J., 51 (7) (1971) 75-76; 4 figs., 1 ref. (Transl. by P.E.R.A. of Gt. Britain of Vestn. Mashinostr., 51 (7) (1971) 72-74.) Oxidising agents such as hydrogen peroxide and potassium permanganate have been used in metal cutting experiments. By forming chemical films on the tool and chip contact faces atomic oxygen or active chlorine give 3&70% greater life of high-speed steel and cemented carbide tools than standard emulsion an optimum chemical additive concentration of 0.5-1.0% was determined. A new cutting fluid was developed. Rollmg Element Fatigue and Lubrication with Fluorinated Polyetbers at Cryogenic Temperatures. M. W. Dietrich, D. P. Townsend and E. V. Zaretsky, JOLT, Ser. F 93 (3) (1971) 364370; 12 figs., 1 table, 21 refs. Using a modified, five-ball fatigue tester four fluorinated polyether lubricants and a superrefined naphthenic mineral oil were compared. There were no statistical differences between the Wear, 21 (1972)
Lubricating Greases for Rolling Bearings. R. A. Clarke, BaN Bearing J., 167 (1971) 1418; 7 figs., 1table. A discussion of lubricating greases for rolling bearings. Grease types and properties are tabulated. The Compressibility
of Selected
Fluids at Pres-
sures up to 230,000 psi.
I. B. Gordman, N. Ahmed, P. S. Venkatesan and J. S. Cartwright, Lubrication Eng., 27 (10) (1971) 334341; 13 figs., 4 tables, 11 refs. Data on the compressibilities of metal forming, hydraulic and synthetic fluids are presented and discussed. A set up of a high pressure chamber in conjunction with a 50 ton hydraulic press enabled compressibilities up to 230,000 psi to be measured. It was found that in general uncompounded synthetic fluids are more compressible than petroleum based fluids, especially at low loads. Temperature Rise Characteristics of Greases in Rolling Element Bearings. A. C. Horth, J. H. Norton and W. C. Pattenden, Lubrication Eng., 27 (11) (1971) 380-385; 4 figs., 9 tables, 2 refs. The equilibrium temperature rise of grease lubricated bearings was found to be a function of the consistency or soap content of the grease used. Bearings lubricated with very soft or very hard products run cooler than those lubricated with products of medium consistency. It is not possible to define a value of the penetration at which any grease will channel in a bearing and conse-
407
Speed and the condition of the carrier at the moment of deformation were found to be the variables that determined the relative performance of forging lubricants. The Hydrodynamic Lubrication of Rough Bearing Surfaces of Finite Width. H. Christensen and K. Tonder, JOLT, Ser. F 93 (3) (1971) 324-330; 9 tigs., 15 refs. A theoretical analysis of the effects of surface roughness in a finite width bearing based on a stochastic theory of hydrodynamic iubrication. The effect of surface roughness on the bearing characteristics is limited with features of nominal geometry and operating factors. Fluid Rheuiogical Effecta in Sliding Satyrdynamic Point Contacts with Transient Loading: Traction. D. M. Sanbom and W. 0. Winer, JOLT, Ser. F 93 (3) (1971) 342-348; 7 figs., 1 table, 17 refs. Traction values experimentally obtained under the conditions investigated appear to be primarily a function of the sliding velocity. Large variations in fluid composition and inlet viscosity had little influence on the tractive force; rapid application of the normal load had a negligible effect. Optical Analysis of Ball Bearing Starvation. L. D. Wederen, D. Evans and A. Cameron, JOLT, Ser F 93 (3) (1971) 349-363; 24 figs., 2 tables, 29
3.1. Lubrication
refs. Experimental oil tihn measurements obtained by optical interferometry for rolling point contact under starvation conditions illustrates the starvation phenomenon and agrees with theoretical predictions. Starvation inhibits the generation of pressure and reduces film thickness, causes overall pressure, stress and elastic deformation to become more Hertxian. Experiments using interferometry illustrate the cavitation pattern, lubricant entrap ment, grease lubrication, ball spin and edge effects in line contact.
Speed Effects in Forging tibrication. P. W. Waliace and J. A. Schey, JOLT, Ser. F 93 (3)(1971)317-323;1lligs.,22refs. The effect of forging speed on the efficiency of solid and liquid lubricants on the axial upsetting of C steel cylinders and rings was investigated. Increasing speed reduced friction both unlubricated and with lubricants which formed a hydrodynamic film. Carrier fluids with solid lubricants were effective when contact time was short enough to prevent evaporation; residues of a mineral oil carrier impaired the effectiveness of graphite.
Oil F&n Thickness and Rolling Friction in ElaatoHydrodynamicPoint Contact. R. Gohar, JOLT, Ser. F 93 (3) (1971) 371-382; 16 figs., 25 refs. Using a rolling ball and plate machine the effect of material properties on the Blm thickness in point contact is demonstrated. The oil film measured by inte~eromet~ shows no significant alteration over a wide range of Young’s modulus and high pressure and is insensitive to the choice of boundary materials. The rolling friction between
3.
LUBRICATION AND LUBRICANTS
Wear, 21(1972)
408
SYSTEMATIC
ABSTRACTS
OF CURRENT
LITERATURE
a tungsten carbide ball and a glass plate is determined and compared with theory. The effect of spin is found to be slight.
polyether fluid at 500”R and the oil at 305”R therefore no derating of SAE 52100 steel with the polyether at low temperature is necessary.
Oil Lubrication of Rolling Bearings. R.Hobbs, Tribology,4(4)(1971) 198-204; 11 figs., 10 refs. A method of selecting suitable grades of oil is suggested and methods of lubricating oil application are described. Operating characteristics are discussed and some limitations of bearing performance are given.
The Starting Torques and Rheology of Lubricating Greases at Low Temperatures. E. Thelen, M. .I. Devine and L. J. Stalhngs, Lubrication Eng., 27 (9) (1971) 305-310; 7 figs., 3 tables, 13 refs. A study of yield pressure, starting torque and consistency values of lubricating greases at low temperature. Experiments were conducted aimed at relating low-temperature torque to other grease properties. Log torque for a typical grease decreased linearly with log time for 10 to 40 min then abruptly the curve becomes more precipitous and a new linear segment is produced. After 1040 min at the new increased slope, equilibrium is reached and the torque abruptly ceases to change with time; 9 of 19 greases tested followed this pattern. Among the other 10 greases 5 variations of this pattern were displayed.
A Thermodynamic Method of Bearing Analysis. A. Nica, Tribology, 4 (4) (1971) 218-226; 13 figs., 24 refs. The coupled Reynolds and energy equations are considered for both thrust and journal bearings. The one dimensional solutions arc provided with correction coefficients depending on the actual bearing width, resulting in ready for use relations. Diagrams obtained by numerical treatment are presented for finite bearings, besides the analytical relations for actual design arrangements. Comparisons with experimental results are satisfactory.
3.2. Liquid Lubricants Oxygen-containing Cutting Fluids Increase Tool Life. V. N. Latyshev, Russian Eng. J., 51 (7) (1971) 75-76; 4 figs., 1 ref. (Transl. by P.E.R.A. of Gt. Britain of Vestn. Mashinostr., 51 (7) (1971) 72-74.) Oxidising agents such as hydrogen peroxide and potassium permanganate have been used in metal cutting experiments. By forming chemical films on the tool and chip contact faces atomic oxygen or active chlorine give 3&70% greater life of high-speed steel and cemented carbide tools than standard emulsion an optimum chemical additive concentration of 0.5-1.0% was determined. A new cutting fluid was developed. Rollmg Element Fatigue and Lubrication with Fluorinated Polyetbers at Cryogenic Temperatures. M. W. Dietrich, D. P. Townsend and E. V. Zaretsky, JOLT, Ser. F 93 (3) (1971) 364370; 12 figs., 1 table, 21 refs. Using a modified, five-ball fatigue tester four fluorinated polyether lubricants and a superrefined naphthenic mineral oil were compared. There were no statistical differences between the Wear, 21 (1972)
Lubricating Greases for Rolling Bearings. R. A. Clarke, BaN Bearing J., 167 (1971) 1418; 7 figs., 1table. A discussion of lubricating greases for rolling bearings. Grease types and properties are tabulated. The Compressibility
of Selected
Fluids at Pres-
sures up to 230,000 psi.
I. B. Gordman, N. Ahmed, P. S. Venkatesan and J. S. Cartwright, Lubrication Eng., 27 (10) (1971) 334341; 13 figs., 4 tables, 11 refs. Data on the compressibilities of metal forming, hydraulic and synthetic fluids are presented and discussed. A set up of a high pressure chamber in conjunction with a 50 ton hydraulic press enabled compressibilities up to 230,000 psi to be measured. It was found that in general uncompounded synthetic fluids are more compressible than petroleum based fluids, especially at low loads. Temperature Rise Characteristics of Greases in Rolling Element Bearings. A. C. Horth, J. H. Norton and W. C. Pattenden, Lubrication Eng., 27 (11) (1971) 380-385; 4 figs., 9 tables, 2 refs. The equilibrium temperature rise of grease lubricated bearings was found to be a function of the consistency or soap content of the grease used. Bearings lubricated with very soft or very hard products run cooler than those lubricated with products of medium consistency. It is not possible to define a value of the penetration at which any grease will channel in a bearing and conse-