摘要:

A pin and disk machine has been used to investigate the influence of load and stress on the wear of steel specimens lubricated with a plain mineral oil and two blends containing typical commercial EP additives.

ISSN:0569-8197    

DOI:10.1080/05698196508972083

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Interferometric examination and taper sectioning were used to elucidate the microtopography of the contacting surfaces of a finely ground disk and a conically ended rider. The question of the real area of contact when these surfaces are put together under high pressure is considered. Inspection of the wear track on the disk after a short interval of rubbing, with either white oil or a compounded oil, revealed that visible evidence of true metal-to-metal contact was quite sparse in comparison to the potential real area of contact deduced from microtopographical considerations. The scar on the end of the rider, on the other hand, showed evidence of extensive rubbing, as a consequence of the high ratio of the area of the disk track to the area on the end of the rider. The two rubbing surfaces were in a relatively smooth condition; therefore the wear particles must have been small and sparse. When the rubbing path was reiterated many times, the alteration of the contacting surfaces by previous rubbing affected the course of wear on subsequent rubbing. The effect of the lubricant became apparent at this stage of the wear process.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Washington, D. C., October 13–16, 1964.1The fifth in a series of communications on extreme-pressure lubrication and wear from the author's laboratories.

ISSN:0569-8197    

DOI:10.1080/05698196508972084

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Friction and wear data, obtained with a crossed-cylinders apparatus, are presented for a selection of molybdenum-tungsten-chromium alloys, over the temperature range 200–500 C, for two sodium environments: the molten metal, containing approximately 5 ppm of oxygen impurity, and pure argon containing sodium vapor at concentrations corresponding with the temperature equilibrium value. Some comparisons are made with results obtained in gaseous environments of pure argon, helium, and carbon dioxide. An indication is given of the effect on friction and wear behavior of increasing the oxygen content in liquid sodium from about 5 to 80 ppm.

ISSN:0569-8197    

DOI:10.1080/05698196508972085

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Friction, wear, and metal-transfer characteristics were determined for rare-earth and related metals in vacuum to 10−10mm of mercury. The metals studied were lanthanum, neodymium, praseodymium, cerium, holmium, erbium, gadolinium, dysprosium, samarium, yttrium, and thallium. Friction and wear experiments were conducted with the rare-earth or related metals generally sliding against 440-C stainless steel.

ISSN:0569-8197    

DOI:10.1080/05698196508972086

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

This paper contains the results of measurements of sliding friction on copper surfaces at 10−6−10−9torr for five lamellar solids, namely, molybdenum sulfide, tungsten sulfide, cadmium iodide, bismuth iodide, and phthalocyanine. There is no evidence that the sliding behavior of any of these materials is improved by the presence of gas or vapors. Each evolved considerable Quantities of gas during sliding.

ISSN:0569-8197    

DOI:10.1080/05698196508972087

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Experiments are described to determine the lubricating ability of various solid films, particularly graphite and molybdenum disulfide, transferred from a compact to a steel surface. The amount of lubricant transferred depends markedly on the surface finish of the steel, and the most effective films are formed on relatively rough surfaces. In these conditions, bonding between the film and its substrate appears to be primarily mechanical. Determinations of the scuffing load and endurance tests show that replenishment of the lubricant film by continuous transfer to compensate for wear is only possible to a limited extent. With molybdenum disulfide, the film ultimately wears away, but with graphite, failure occurs when the mean surface temperature exceeds about 100 C. The load-carrying capacity of transferred films of molybdenum disulfide is appreciably greater than that of graphite films.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Washington, D.C., October 13–16, 1964.

ISSN:0569-8197    

DOI:10.1080/05698196508972088

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

The effect of oxygen on the life expectancy of a run-in molybdenum disulfide film under heavy load has been studied. Tested in argon, with only small quantities of oxygen present, the smooth running period is increased by at least two decades as compared to a test in oxygen.

ISSN:0569-8197    

DOI:10.1080/05698196508972089

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

The kinetic coefficient of friction was determined for several grades of commercially available molybdenum disulfide powder. These powders were individually applied to separate steel-supporting substrates to form a thin lubricant film. Friction measurements were made at loads ranging from 0.1 to 10 kg and at a slow speed of sliding. The results of Ike investigation showed that the coefficient of friction decreased with increasing load, contrary to Amontons' Second Law. A theory was postulated to explain the observed variation in the friction coefficient with load, It was concluded that the variation in the friction coefficient could be explained solely on the basis of the macroelastic and/or macroelastic and plastic deformation characteristics of the supporting substrates.1The opinions expressed in this paper are those of the author and are not to be construed as official or reflecting the views of the Department of the Navy or the naval service at large.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Washington, D.C., October 13–16, 1964.

ISSN:0569-8197    

DOI:10.1080/05698196508972090

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

A discussion of factors affecting the choice of an equation of state for the description of non-Newtonian viscoelastic lubricants is given. Based on a compromise between realism and complexity, simple solutions for squeeze films with and without superimposed steady shears are given. These illustrate the complexity of the action of these fluids, including the variation of the effective relaxation time and the “softening” of the film under dynamic loading.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Washington, D. C., October 13–36, 1964.

ISSN:0569-8197    

DOI:10.1080/05698196508972091

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Many non-Newtonian steady-state flow curves are characterized by the existence of initial and ultimate Newtonian flow regions. A study of such flow patterns leads to the conclusion that the principle flow parameter is the rate of energy input (shear stress times shear rate) rather than either of these used independently. It is postulated that the logarithm of the viscosity is normally distributed between the limits of the first and second Newtonian regions when referred to the logarithm of the rate of energy input. This permits the flow data to be expressed as a straight-line relationship over the full flow range. Application of this technique is made to known polymer-solvent systems to demonstrate its validity. This permits the predictive extension of data from a minimum of experimental data.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Washington, D.C., October 13–16, 1964.

ISSN:0569-8197    

DOI:10.1080/05698196508972092

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor