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Friction and scoring under the conditions of simultaneous rolling and sliding of bodies
ABSTRACTS Copies of original articles are best obtained by writing direct to the journal in which they appeared. The addresses of journals can be found in a reference book such as
‘W&d List of Scientific and Technical Publications’, ‘Willings Press Guide’, Newspaper Press Directory’ for American journals only, ‘Ayers’.
ALEXANDER, Propagation
DI §APIO, A. and MALONEY, The lubricating performance film in air and in liquids.
D. L. of surface
disturbances
on radially
loaded
discs. Transactions of the American Society of Lubrication Engineers, Vol. 11, NO. 1 (January 1968) ~~‘72-80 An analysis is given which shows how an initial point disturbance on the surface of one disc of a pair of radially loaded discs rolling and sliding in contact will grow and propagate other surface disturbances on both discs. In the analysis it is assumed that an area becoming disturbed will be able to cause disturbances on surfaces which come into contact with it. A comparison has been drawn between the patterns of the disturbances formed and scuff patterns on pairs of failed discs and significant similarities are shown. The number of disturbances and the spaces of the leading edges of the disturbances are similar to the number and spacing of the scuff marks. The analysis gives lengths of the disturbances which are longer than the scuff marks. It is concluded that the analysis is helpful in understanding failures on discs, and it can be extended to scuff propagation on gears. (9 figures, 2 tables, 2 references) (Tribology 1968, abstract 99) ARCHARD, J. F. Non-dimensional parameters in isothermal theories of elastohydrodynamic lubrication. Journal of .Mechanical Engineering Science,Vol 10,No 2 (April 1968) ~~165-167 Non-dimensional parameters used in the presentation of theories of elastohydrodynamic lubrication are here judged by the extent to which they can be given an acceptable physical meaning. A suitable basis for this is provided by considering the sequence of events as the load is increased. (1 figure, 5 references) (Tribology 1968, abstract 100) BARLOW, D. A. A thermal size effect in friction tests. Wear, Vol 11, No 3 (March 1968) pp229-323 Sliding indentation tests with hard indenters on soft lead surfaces have shown that, for given contact pressure and speed of sliding, the temperature rise is a function of indenter radius. This would be expected from the theoretical calculations of temperature rise. This size effect may explain differences in frictional behaviour between large scale tests on gramophone record plastic and actual records under playing conditions. (2 figures, 7 references) (Tribology 1968, abstract 101) BRENDEL, H. and WAGNER, K. Radioaktive untersuchungen zur verschleissentstehung beim senkrechechten auseinanderreissen zweier Zilgeschmierter ebener stahlscheiben. Wear, Vol 11, No 4 (April 1968) pp277-290 (In German) An iron plate was neutron-activated in a nuclear reactor to specific activities of about lmC/g of 5sFe and 5lCr. The lapped surface (about 14cm2) of this plate was pressed against a lubricated non-radioactive iron plate in a loading equipment. The radioactive piece was then torn from the non-radioactive plate by a shearing apparatus with high shear velocity. As a result there was some radioactive material on the surface of the non-radioactive inserted plate and in the residues of lubrication oil which were washed from the radioactive plate, thus showing that wear occurs. The experiments demonstrated that the separation of radioactive material is caused by the shearing process, not by loading, corrosion or unintended tangential displacement of the plates. The effects of shear velocity and lubricating oil on wear were investigated. The results confirm a prediction made by Pietsch from an empirical equation uzt, = constant (uz = shear stress, tz = shear time). According to this the volume tensile strength of a lubrication oil film in the case of high shear velocities can become as high as the tensile strength of microregions of the metal. Radioautographs of the non-radioactive inserted plate showed such behaviour only for a few spots distributed irregularly over the surface. (14 figures, 9 references) (Tribology 1968, abstract 102) 188
TRIBOLOGY
August 1968
and.
J. of an ‘in-situ’
process
MoS,
Transactions of the American Engineers, No 1 (January 1968)
Society of Lubrication ~~56-63 The performance of a synthetic molybdenum disulphide film, produced by electrodeposition of molybdic oxide followed by a temperature-pressure hydrogen sulphide conversion to a molybdenum sulphide compound, is examined, immersed in various fluids, under extreme pressure conditions. Friction, wear and extreme pressure characteristics, measured on various test machines, are compared with those of the fluids alone and also with conventional bonded films, The fluids examined include mineral oil, jet fuel, hydraulic fluid and silicone fluid. The dry films include burnished molybdenum disulphide powder, MIL-L-8937 resin bonded film, MIL-L8129 silicate bonded film and the synthetic ‘in-situ’ molybdenum disulphide film. The performance of the synthetic molybdenum disulphide film on titanium and stainless steel is also examined. (9 figures, 6 tables, 15 references) (Tribology 1968, abstract 103)
DROZDOV, Y _N , and GAVRIKOV, Friction rolling
and scoring and sliding
under
Y. A.
the conditions
of simultaneous
of bodies. Wear, Vol 11, No 4 (April 1968) pp291-302 A roller (disc) type machine is described with an open power (mechanical) and kinematic circuit and a new procedure for scoring tests under heavy contact loads for simultaneous rolling and sliding of bodies. The results of the investigation of the sliding friction coefficient and the empirical formulae for its determination are given. A study of the different factors affecting scoring has proved that none of the existing scoring criteria remains constant in all the instances when scoring begins. A new experimental and theoretical criterion for scoring calculations is suggested. (8 figures, 2 tables, 19 references) (Tribology 1968, abstract 104)
EDWARDS, C. M. and HALLING, J. An analysis of the plastic interaction ties
and its
relevance
to the value
of surface asperiof the coefficient of
friction. Journal of Mechanical Engineering Science, Vol 10,No 2 (April 1968) pplOl-110 Surface asperities are considered as wedge-shaped bodies which 3re plastically deformed wherever relative motion occurs between mating surfaces. This plastic interaction produces interfacial forces between the surface asperities which are considered, in the collective sense, to represent the total applied normal and tangential forces acting on the sliding surfaces. A solution is proposed which enables the values of the interfacial forces to be obtained at each time interval during the life history of a junction interaction. Furthermore, the nature of these forces is shown to be fnarkedly dependent on both the initial asperity geometry and on the nature of any surface films which may be present at the asperity interfaces. The macroscopic values of the coefficient of sliding friction are predicted. It is also demonstrated that very large values of the macroscopic coefficient of friction are associated with very strong molecular adhesion of the surface asperities particularly for materials having high ductility. (10 figures, 12 references) (Tribology 1968, abstract 105)
‘W&d List of Scientific and Technical Publications’, ‘Willings Press Guide’, Newspaper Press Directory’ for American journals only, ‘Ayers’.
ALEXANDER, Propagation
DI §APIO, A. and MALONEY, The lubricating performance film in air and in liquids.
D. L. of surface
disturbances
on radially
loaded
discs. Transactions of the American Society of Lubrication Engineers, Vol. 11, NO. 1 (January 1968) ~~‘72-80 An analysis is given which shows how an initial point disturbance on the surface of one disc of a pair of radially loaded discs rolling and sliding in contact will grow and propagate other surface disturbances on both discs. In the analysis it is assumed that an area becoming disturbed will be able to cause disturbances on surfaces which come into contact with it. A comparison has been drawn between the patterns of the disturbances formed and scuff patterns on pairs of failed discs and significant similarities are shown. The number of disturbances and the spaces of the leading edges of the disturbances are similar to the number and spacing of the scuff marks. The analysis gives lengths of the disturbances which are longer than the scuff marks. It is concluded that the analysis is helpful in understanding failures on discs, and it can be extended to scuff propagation on gears. (9 figures, 2 tables, 2 references) (Tribology 1968, abstract 99) ARCHARD, J. F. Non-dimensional parameters in isothermal theories of elastohydrodynamic lubrication. Journal of .Mechanical Engineering Science,Vol 10,No 2 (April 1968) ~~165-167 Non-dimensional parameters used in the presentation of theories of elastohydrodynamic lubrication are here judged by the extent to which they can be given an acceptable physical meaning. A suitable basis for this is provided by considering the sequence of events as the load is increased. (1 figure, 5 references) (Tribology 1968, abstract 100) BARLOW, D. A. A thermal size effect in friction tests. Wear, Vol 11, No 3 (March 1968) pp229-323 Sliding indentation tests with hard indenters on soft lead surfaces have shown that, for given contact pressure and speed of sliding, the temperature rise is a function of indenter radius. This would be expected from the theoretical calculations of temperature rise. This size effect may explain differences in frictional behaviour between large scale tests on gramophone record plastic and actual records under playing conditions. (2 figures, 7 references) (Tribology 1968, abstract 101) BRENDEL, H. and WAGNER, K. Radioaktive untersuchungen zur verschleissentstehung beim senkrechechten auseinanderreissen zweier Zilgeschmierter ebener stahlscheiben. Wear, Vol 11, No 4 (April 1968) pp277-290 (In German) An iron plate was neutron-activated in a nuclear reactor to specific activities of about lmC/g of 5sFe and 5lCr. The lapped surface (about 14cm2) of this plate was pressed against a lubricated non-radioactive iron plate in a loading equipment. The radioactive piece was then torn from the non-radioactive plate by a shearing apparatus with high shear velocity. As a result there was some radioactive material on the surface of the non-radioactive inserted plate and in the residues of lubrication oil which were washed from the radioactive plate, thus showing that wear occurs. The experiments demonstrated that the separation of radioactive material is caused by the shearing process, not by loading, corrosion or unintended tangential displacement of the plates. The effects of shear velocity and lubricating oil on wear were investigated. The results confirm a prediction made by Pietsch from an empirical equation uzt, = constant (uz = shear stress, tz = shear time). According to this the volume tensile strength of a lubrication oil film in the case of high shear velocities can become as high as the tensile strength of microregions of the metal. Radioautographs of the non-radioactive inserted plate showed such behaviour only for a few spots distributed irregularly over the surface. (14 figures, 9 references) (Tribology 1968, abstract 102) 188
TRIBOLOGY
August 1968
and.
J. of an ‘in-situ’
process
MoS,
Transactions of the American Engineers, No 1 (January 1968)
Society of Lubrication ~~56-63 The performance of a synthetic molybdenum disulphide film, produced by electrodeposition of molybdic oxide followed by a temperature-pressure hydrogen sulphide conversion to a molybdenum sulphide compound, is examined, immersed in various fluids, under extreme pressure conditions. Friction, wear and extreme pressure characteristics, measured on various test machines, are compared with those of the fluids alone and also with conventional bonded films, The fluids examined include mineral oil, jet fuel, hydraulic fluid and silicone fluid. The dry films include burnished molybdenum disulphide powder, MIL-L-8937 resin bonded film, MIL-L8129 silicate bonded film and the synthetic ‘in-situ’ molybdenum disulphide film. The performance of the synthetic molybdenum disulphide film on titanium and stainless steel is also examined. (9 figures, 6 tables, 15 references) (Tribology 1968, abstract 103)
DROZDOV, Y _N , and GAVRIKOV, Friction rolling
and scoring and sliding
under
Y. A.
the conditions
of simultaneous
of bodies. Wear, Vol 11, No 4 (April 1968) pp291-302 A roller (disc) type machine is described with an open power (mechanical) and kinematic circuit and a new procedure for scoring tests under heavy contact loads for simultaneous rolling and sliding of bodies. The results of the investigation of the sliding friction coefficient and the empirical formulae for its determination are given. A study of the different factors affecting scoring has proved that none of the existing scoring criteria remains constant in all the instances when scoring begins. A new experimental and theoretical criterion for scoring calculations is suggested. (8 figures, 2 tables, 19 references) (Tribology 1968, abstract 104)
EDWARDS, C. M. and HALLING, J. An analysis of the plastic interaction ties
and its
relevance
to the value
of surface asperiof the coefficient of
friction. Journal of Mechanical Engineering Science, Vol 10,No 2 (April 1968) pplOl-110 Surface asperities are considered as wedge-shaped bodies which 3re plastically deformed wherever relative motion occurs between mating surfaces. This plastic interaction produces interfacial forces between the surface asperities which are considered, in the collective sense, to represent the total applied normal and tangential forces acting on the sliding surfaces. A solution is proposed which enables the values of the interfacial forces to be obtained at each time interval during the life history of a junction interaction. Furthermore, the nature of these forces is shown to be fnarkedly dependent on both the initial asperity geometry and on the nature of any surface films which may be present at the asperity interfaces. The macroscopic values of the coefficient of sliding friction are predicted. It is also demonstrated that very large values of the macroscopic coefficient of friction are associated with very strong molecular adhesion of the surface asperities particularly for materials having high ductility. (10 figures, 12 references) (Tribology 1968, abstract 105)