- Email: [email protected]
Structural changes in graphitized materials during wear
LITERATURE
252 of crude oil fuel high in corrosive sulphur, can be eliminated by treating the lubricating oil with metallic sodium (or potassium), Fresh sodium surface must be exposedcontinuously; otherwise it becomes inactivated by accumulated corrosion product. The effectiveness of sodium was attributed to the large free energy of formation of sodium sulphide relative to silver sulphide and sodium oxide. Otheralkaline-reactingmetalsandcompounds do not protect against corrosion except for sodium oxide and hydroxide which protected in laboratory tests but still have to be evaluated in engine performance. No deleterious effects of the sodium treatment were observed. Structural Changes in Graphitized Materials During Wear. L. P. Grigorenko, L. A. Plutalova and B. M. Hovinskii, Soviet Phys.-Doklady, IO (2) (1965) 154-156.
(Translation 160
(4)
of Doklady
(1965)
807-810
Akad.
by
Nauk
Am.
SSSR,
Inst.
of
Physics, New York, N.Y.) (Source: Appl. Mech. Rev., q (IO) (1966) 915.) The structure of wear particles resulting from friction of graphitized surfaces of steel,copper, and chromium was studied by X-ray diffraction At low loads the wear process involved low friction and little abrasion and resulted in forming films of graphite crystals. At higher loads there was high friction and rapid abrasion with resulting surface damage. The transition from one process to the other occurred at a critical pressure highly dependent on the composition of the surrounding gas.
AND
CURREST
EVESTS
by the National Engineering Laboratory, East Kilbride, Glasgow, Scotland on behalf of the Society of Cosmetic Chemists of Gt. Britain, 1960, 14 pp.; 7 figs., z tables, IO refs. A radioactive tracer technique has been used to assess the abrasiveness of dentifrices with the specific object of acquiring knowledge for the establishment of a standard dentifrice test procedure. A detailed study has been made of the relationships that exist between the wear resistance of dental tissues and their indentation hardness when using abrasives of different hardnesses. The influence on the wear rate of initial surface preparation of the tissues has been investigated together with the affect of decalcification brought about by exposure to lactic acid. 5.5. Erosion alzd cavitation
erosion
A Discussion on Deformation of Solids by the Impact of Liquids, and its Relation to Rain Damage in Aircraft and Missiles, to Blade Erosion in Steam Turbines, and to Cavitation Erosion. Organized by F. P. Bowden, published as a supplement to Phil. Trans. Roy. Sot. (London), A260 (1110) (1966) 7x-315, including discussions. Price: g8.8.0 (U.S. $25.00). For contents see the following abstracts.
(Source: AppZ. Mech. Rev., 19 (9) (1966) 829.) Using a steel-cutting tool bit for the machining of graphite, the rate of wear was found to decrease with increasing cutting speed. Even at 3000 f.p.m., the temperature at the cutting face did not exceed 570°F. As these were deviations from Amontons’ law, there was also no direct correlation between the rate of wear and the apparent coefficient of friction (i.e., the ratio between force of friction and normal load varied with the cutting speed up to about 350 f.p.m.). The relaxation time of the graphite was measured (about 7.r.10-4 set). This is the same order of magnitude as the duration (about 4.10-4 set) of a single sweep of abrasion over the wear land (0.0158 in.) at a speed of rg7 f.p.m., indicating that the rheological properties of graphite have some bearing on tool wear.
I. J. H. Brunton High-speed Liquid Impact. pp. 79-85, 7 figs., 14 refs. A study has been made of the deformation at high strain rates of solids under the impact of liquids. A method is described for projecting a short liquid jet against a solid surface at speeds up to 1200 m/set. The flow of the liquid and the deformation of the solid during impact have been examined by highspeed photographic methods. An attempt has been made to measure the magnitude and duration of the load by means of a piezoelectric pressure transducer. There is evidence that the liquid behaves initially on impact in a compressible manner. Part of the deformation of the solid is due to this compressible behaviour and part to the erosive shearing action of the liquid flowing at very high speeds out across the surface. The mode of deformation in brittle and in plastically deforming materials has been investigated. The deformation patterns produced are shown to be characteristic of liquid impact, The predominating mechanism of deformation depends on the mechanical properties of the solid and on the velocity of impact.
The Measurement and Interpretation of Dentifrice Abrasiveness. K. H. 1~. Wright and J. I. Stevenson, printed
11. J. E. Field Stress Waves, Deformation Caused by Liquid Impact.
Rheological Aspects of Tool Wear in Machining Graphite. H. Takeyama, Trans. ASME, 87 B (3) (1965) 359-364
Wear,
(J. Eng.
10 (‘967)
Id.).
245-259
and
Fracture
252 of crude oil fuel high in corrosive sulphur, can be eliminated by treating the lubricating oil with metallic sodium (or potassium), Fresh sodium surface must be exposedcontinuously; otherwise it becomes inactivated by accumulated corrosion product. The effectiveness of sodium was attributed to the large free energy of formation of sodium sulphide relative to silver sulphide and sodium oxide. Otheralkaline-reactingmetalsandcompounds do not protect against corrosion except for sodium oxide and hydroxide which protected in laboratory tests but still have to be evaluated in engine performance. No deleterious effects of the sodium treatment were observed. Structural Changes in Graphitized Materials During Wear. L. P. Grigorenko, L. A. Plutalova and B. M. Hovinskii, Soviet Phys.-Doklady, IO (2) (1965) 154-156.
(Translation 160
(4)
of Doklady
(1965)
807-810
Akad.
by
Nauk
Am.
SSSR,
Inst.
of
Physics, New York, N.Y.) (Source: Appl. Mech. Rev., q (IO) (1966) 915.) The structure of wear particles resulting from friction of graphitized surfaces of steel,copper, and chromium was studied by X-ray diffraction At low loads the wear process involved low friction and little abrasion and resulted in forming films of graphite crystals. At higher loads there was high friction and rapid abrasion with resulting surface damage. The transition from one process to the other occurred at a critical pressure highly dependent on the composition of the surrounding gas.
AND
CURREST
EVESTS
by the National Engineering Laboratory, East Kilbride, Glasgow, Scotland on behalf of the Society of Cosmetic Chemists of Gt. Britain, 1960, 14 pp.; 7 figs., z tables, IO refs. A radioactive tracer technique has been used to assess the abrasiveness of dentifrices with the specific object of acquiring knowledge for the establishment of a standard dentifrice test procedure. A detailed study has been made of the relationships that exist between the wear resistance of dental tissues and their indentation hardness when using abrasives of different hardnesses. The influence on the wear rate of initial surface preparation of the tissues has been investigated together with the affect of decalcification brought about by exposure to lactic acid. 5.5. Erosion alzd cavitation
erosion
A Discussion on Deformation of Solids by the Impact of Liquids, and its Relation to Rain Damage in Aircraft and Missiles, to Blade Erosion in Steam Turbines, and to Cavitation Erosion. Organized by F. P. Bowden, published as a supplement to Phil. Trans. Roy. Sot. (London), A260 (1110) (1966) 7x-315, including discussions. Price: g8.8.0 (U.S. $25.00). For contents see the following abstracts.
(Source: AppZ. Mech. Rev., 19 (9) (1966) 829.) Using a steel-cutting tool bit for the machining of graphite, the rate of wear was found to decrease with increasing cutting speed. Even at 3000 f.p.m., the temperature at the cutting face did not exceed 570°F. As these were deviations from Amontons’ law, there was also no direct correlation between the rate of wear and the apparent coefficient of friction (i.e., the ratio between force of friction and normal load varied with the cutting speed up to about 350 f.p.m.). The relaxation time of the graphite was measured (about 7.r.10-4 set). This is the same order of magnitude as the duration (about 4.10-4 set) of a single sweep of abrasion over the wear land (0.0158 in.) at a speed of rg7 f.p.m., indicating that the rheological properties of graphite have some bearing on tool wear.
I. J. H. Brunton High-speed Liquid Impact. pp. 79-85, 7 figs., 14 refs. A study has been made of the deformation at high strain rates of solids under the impact of liquids. A method is described for projecting a short liquid jet against a solid surface at speeds up to 1200 m/set. The flow of the liquid and the deformation of the solid during impact have been examined by highspeed photographic methods. An attempt has been made to measure the magnitude and duration of the load by means of a piezoelectric pressure transducer. There is evidence that the liquid behaves initially on impact in a compressible manner. Part of the deformation of the solid is due to this compressible behaviour and part to the erosive shearing action of the liquid flowing at very high speeds out across the surface. The mode of deformation in brittle and in plastically deforming materials has been investigated. The deformation patterns produced are shown to be characteristic of liquid impact, The predominating mechanism of deformation depends on the mechanical properties of the solid and on the velocity of impact.
The Measurement and Interpretation of Dentifrice Abrasiveness. K. H. 1~. Wright and J. I. Stevenson, printed
11. J. E. Field Stress Waves, Deformation Caused by Liquid Impact.
Rheological Aspects of Tool Wear in Machining Graphite. H. Takeyama, Trans. ASME, 87 B (3) (1965) 359-364
Wear,
(J. Eng.
10 (‘967)
Id.).
245-259
and
Fracture