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A technique for the investigation of abrasive wear of metals
LITERATURE
154 been shown to be related to hysteretic properties of the material, but also to surface phenomena like surface tension. The various results obtained and their good reproducibility justify the suggestion of introducing the skid-resistance tester as an important help to the rubber compounder, especially in the field of tires. 6. TESTING
Measurement of Friction of Elastomers by the Skid Resistance Tester. A. C. Bassi, presented by M. deGiorgis, Pirelli Laboratories. (Lecture to the Rubber sion of the American Chemical Society,
DiviApril
29, 1964.) The portable skid-resistance tester proposed and developed by the British Road Research Laboratory, is essentially a pendulum device, which, by an energy balance, can measure the dynamic friction coefficient of road textures with reference to a standard rubber slider. This device, which is extensively used for slipperiness evaluation on wet roads, has been examined for its possibilities as a laboratory instrument for testing dynamic friction coefficients of rubber vulcanizates referred to standard wet surfaces. It offers a fast and inexpensive method for discriminating between tire tread compounds in view of their road friction characteristics. This involved an examination of possible standard surfaces and wetting conditions in order to obtain satisfactory experimental results. Results have, in several instances, also shown a fair correlation with actual road tests of tires and, considering the difficulty of such road comparisons, the apparatus is a valuable help for screening candidate compounds. Several conclusive results have also been found. The effect of various factors, such as type of elastomer and type and content of carbon blacks, has been confirmed on friction coefficient values. Other measurements have been performed on oiled- instead of waterwet surfaces and on smooth ice at various temperatures.
Measurement of High-speed Unlubricated Metallic Friction. I<. Williams, Second Convention on Lubrication and Wear, 1964, Paper I. To be published in the Proc. Inst. Mech. Engrs., London, 1964
The
1965; 7 figs., 13 refs. The procedure adopted for designing a machine for laboratory use which is capable of yielding the desired information under controlled experimental conditions is outlined. Instrumentation is discussed. The apparatus finally developed is fully described and details are given of the experiments conducted. Testing Machines for the Study of Friction and Wear Processes at High Rates of Slip. N. L. Golego. Ind. Lab. (USSR), 29 (6) (1963) Wea+‘, 8 (1965)
X43-155
813.)
(Translation
AND
CURRENT
of Zavodsk.
EVENTS
Lab.,
29
(6)
(‘963) 761). (Source: AppZ. Mech. Rev., 17 (7) (1964) 576.) Two devices for investigation of friction and wear at high and ultra-high slip rates are described.
A Technique for the Investigation Abrasive Wear of Metals. V. N. Tkachev, Ind. Lab. (USSR), 29 (1963)
810. (Translation
of Zavodsk.
Lab.,
of (6) 29
(6) (1963) 758). (Source: Appl. Mech. Rev., 17 (7) (1964) 576.) The wear of the cutting tools of soil-cultivating machinery and implementswasinvestigated in the specially-designed apparatus. The test specimen is rotated against the prepared abrasive mixture of quartz. sand and clay, which is extruded from a mixing bin. The density and abrasiveness of the mixture can be varied to represent various soil conditions and types. Wear on the tool is determined by weight loss and by dial gauge measurements. Tests showed a hyperbolic relationship betwcen linear wear and hardness of the test material. This is in agreement witJl findings of Khrushchev and Babichev who showed a linear relationship between the relative wear resistance (reciprocal of wear) and hardness of material.
The Use of a Motored Engine to Study Piston-ring Wear and Engine Friction. W. C. Pike and D. T. Spillman, Second Convention on Lubrication and Wear, 1964,
Paper II. To be published in the Proc. Inst. Mech. Engvs., London, 196411965; 8 figs., I table, g refs. The paper describes a study of the conditions which lead to mechanical, or attritive, wear of a top piston ring. A motored single-cylinder enginewas used, and piston-ringwear measurcments were made using a radioactive tracer technique. By connecting the inlet and cxhaust ports together and pressurizing the system with nitrogen, peak cylinder pressures could be matched to those in a firing engine and corrosive wear minimized. Ring belt oil viscosities were matched to those in service either by using low-viscosity oils or by restricting the cooling. Wear was caused under steady-speed conditions by increasing the peak pressure or the cylinder-liner temperature. However, even under the most severe conditions, the wear rate eventually became negligible with the liner surface becoming highly polished. Under comparable conditions in a fired engine a steady rate of wear was observed. It was found that large variations in pistonring wear could occur without any detectable change in the motoring torque. Torque was linearly related to the peak cylinder pressure. The component of the motoring torque
154 been shown to be related to hysteretic properties of the material, but also to surface phenomena like surface tension. The various results obtained and their good reproducibility justify the suggestion of introducing the skid-resistance tester as an important help to the rubber compounder, especially in the field of tires. 6. TESTING
Measurement of Friction of Elastomers by the Skid Resistance Tester. A. C. Bassi, presented by M. deGiorgis, Pirelli Laboratories. (Lecture to the Rubber sion of the American Chemical Society,
DiviApril
29, 1964.) The portable skid-resistance tester proposed and developed by the British Road Research Laboratory, is essentially a pendulum device, which, by an energy balance, can measure the dynamic friction coefficient of road textures with reference to a standard rubber slider. This device, which is extensively used for slipperiness evaluation on wet roads, has been examined for its possibilities as a laboratory instrument for testing dynamic friction coefficients of rubber vulcanizates referred to standard wet surfaces. It offers a fast and inexpensive method for discriminating between tire tread compounds in view of their road friction characteristics. This involved an examination of possible standard surfaces and wetting conditions in order to obtain satisfactory experimental results. Results have, in several instances, also shown a fair correlation with actual road tests of tires and, considering the difficulty of such road comparisons, the apparatus is a valuable help for screening candidate compounds. Several conclusive results have also been found. The effect of various factors, such as type of elastomer and type and content of carbon blacks, has been confirmed on friction coefficient values. Other measurements have been performed on oiled- instead of waterwet surfaces and on smooth ice at various temperatures.
Measurement of High-speed Unlubricated Metallic Friction. I<. Williams, Second Convention on Lubrication and Wear, 1964, Paper I. To be published in the Proc. Inst. Mech. Engrs., London, 1964
The
1965; 7 figs., 13 refs. The procedure adopted for designing a machine for laboratory use which is capable of yielding the desired information under controlled experimental conditions is outlined. Instrumentation is discussed. The apparatus finally developed is fully described and details are given of the experiments conducted. Testing Machines for the Study of Friction and Wear Processes at High Rates of Slip. N. L. Golego. Ind. Lab. (USSR), 29 (6) (1963) Wea+‘, 8 (1965)
X43-155
813.)
(Translation
AND
CURRENT
of Zavodsk.
EVENTS
Lab.,
29
(6)
(‘963) 761). (Source: AppZ. Mech. Rev., 17 (7) (1964) 576.) Two devices for investigation of friction and wear at high and ultra-high slip rates are described.
A Technique for the Investigation Abrasive Wear of Metals. V. N. Tkachev, Ind. Lab. (USSR), 29 (1963)
810. (Translation
of Zavodsk.
Lab.,
of (6) 29
(6) (1963) 758). (Source: Appl. Mech. Rev., 17 (7) (1964) 576.) The wear of the cutting tools of soil-cultivating machinery and implementswasinvestigated in the specially-designed apparatus. The test specimen is rotated against the prepared abrasive mixture of quartz. sand and clay, which is extruded from a mixing bin. The density and abrasiveness of the mixture can be varied to represent various soil conditions and types. Wear on the tool is determined by weight loss and by dial gauge measurements. Tests showed a hyperbolic relationship betwcen linear wear and hardness of the test material. This is in agreement witJl findings of Khrushchev and Babichev who showed a linear relationship between the relative wear resistance (reciprocal of wear) and hardness of material.
The Use of a Motored Engine to Study Piston-ring Wear and Engine Friction. W. C. Pike and D. T. Spillman, Second Convention on Lubrication and Wear, 1964,
Paper II. To be published in the Proc. Inst. Mech. Engvs., London, 196411965; 8 figs., I table, g refs. The paper describes a study of the conditions which lead to mechanical, or attritive, wear of a top piston ring. A motored single-cylinder enginewas used, and piston-ringwear measurcments were made using a radioactive tracer technique. By connecting the inlet and cxhaust ports together and pressurizing the system with nitrogen, peak cylinder pressures could be matched to those in a firing engine and corrosive wear minimized. Ring belt oil viscosities were matched to those in service either by using low-viscosity oils or by restricting the cooling. Wear was caused under steady-speed conditions by increasing the peak pressure or the cylinder-liner temperature. However, even under the most severe conditions, the wear rate eventually became negligible with the liner surface becoming highly polished. Under comparable conditions in a fired engine a steady rate of wear was observed. It was found that large variations in pistonring wear could occur without any detectable change in the motoring torque. Torque was linearly related to the peak cylinder pressure. The component of the motoring torque