摘要:

A mathematical model based on the existing theories of corrosion and wear is proposed for analyzing the controlling phenomena in corrosive wear caused by atmospheric oxygen. The model is applied to experimental wear data, making the assumption that all of the wear proceeded by a corrosion mechanism, i.e., the growth of an oxide layer and its subsequent removal by rubbing. The analytical results show that the rate of metal oxidation is the more important factor in determining the wear rate. The proposed model, assuming oxidation to follow a parabolic rate law, predicts a much higher rate constant and a lower activation energy for oxidation in corrosive wear than in static corrosion at the same “hot spot” temperature. It is postulated that this is due to a mechanical activation phenomena caused by rubbing action. The increase of wear at higher loads can be accounted for by a simple increase in oxidation rate at a higher surface temperature.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey, October 8–10, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196908972251

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Variables affecting the fatigue life of a rolling contact are identified. A mathematical model of sub-surface and surface crack propagation is presented. The life to failure of volume elements in the vicinity of a defect (defect life) is formulated. A term “severity” of a microdefect has been defined. The model is characterized by the inclusion of bulk material parameters, defect characteristics and parameters of geometry, stress, lubrication and surface topography. A statistical expression for the life of an entire rolling body is based on the defect life formula. The new model comprises current standard bearing life prediction formulas as a special case.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey, October 8–10, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196908972252

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Binders that have been tried for powdered, lamellar, dry lubricants have shortcomings such as hindering the realignment of the lubricant particles or encapsulating the lubricants, making a wearing-in process necessary. A microfibrous form of colloidal alumina (boehmite) is shown to act as a superior nonencapsulating binder for molybdenum disulfide in the formation of ductile, water-resistant dry lubricant films. Such films exhibit lower coefficients of friction than have been reported for molybdenum disulfide or graphite films bonded with any other material. These new lubricating coatings have good load-carrying ability and durability at any temperature below the thermal decomposition temperature of molybdenum disulfide (700 F). Optimum performance of these boehmite-bonded films is obtained when: (a) the weight ratio of fibrillar boehmite to MoS2is near 0.20; (b) the film is 0.2 to 0.5 mil thick; (c) the substrate is hard and highly polished; and (d) the film is applied as an alkaline dispersion (pH = 10) and then dehydrated by baking at 550 F.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey, October 8–10, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196908972253

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A method is presented for obtaining vapor pressures over the temperature range of interest in engine lubrication (300–500 F). The determination is based on the saturation efficiency of an air stream and the relationship between vapor pressure and evaporation loss. All data required are readily obtained from the ASTM Evaporation Test Method D 972-56 which is already used in connection with the evaporation loss specification of turbo oils. In addition to vapor pressure, the method is also used to estimate the flash point of these same lubricants.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey, October 8–10, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196908972254

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

An analysis is made of the infinite slider bearing with transverse cooling of the oil film. The results were obtained by numerically solving simultaneously the equations of motion and energy in which the lubricant viscosity depends on temperature. With an adiabatic condition at the runner and a parabolic inlet temperature distribution, the difference between the runner temperature and pad surface temperature for the fully-cooled film depends on the pad temperature, slide speed, and fluid properties. The slider losses and load capacity can be greater or lesser than those predicted by classical solutions based on viscosity at the pad surface temperature though the optimum pivot location for the same film thickness ratio remains unchanged.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey, October 8–10, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196908972255

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Oxygen and moisture are shown to cause a significant increase in friction and wear under non-scuffing conditions. In certain cases, wear in humid air is destructive, but can be entirely eliminated by blanketing the system in dry nitrogen. This pro-wear effect of air is entirely reversible it occurs with most metallurgies and lubricant types, and it may be controlled by incorporating suitable additives in the oil. Various wear mechanisms have been examined to explain the experimental results; the most satisfactory is a simple corrosive wear phenomenon, involving the formation and rubbing away of metal oxides.Presented at the ASME/ASLE Lubrication Conference, Atlantic City, New Jersey, October 8–10, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196908972256

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

This paper discusses test results obtained on a single contact, cylindrical, traction test machine operating at rolling speeds ranging from 5,000 fpm to 25,000 fpm and at maximum Hertz stresses from nearly zero to 200,000 psi. Effects of speed, load and contact length on traction and relative creep between two plain cylinders lubricated with a naphthenic mineral oil were investigated. Test results indicate that coefficient of traction and creep were greatly affected by all three variables tested.

ISSN:0569-8197    

DOI:10.1080/05698196908972257

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The life-margin of oscillating caged needle roller bearings is determined in an explicit non-statistical manner. Life-margin is the difference between the first macroscopic evidence of spalling fatigue and the end of useful bearing life. The bearings were life tested under service conditions closely duplicating those in helicopter rotor vertical and horizontal hinge pin locations. Test results are presented for nineteen bearings lubricated with MIL-L-7808 oil. The use of magnetic chip-detectors and spectrometric oil analysis as failure indicating devices are discussed.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference hold in Atlantic City, New Jersey, October 8–10. 1968.

ISSN:0569-8197    

DOI:10.1080/05698196908972258

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Sliding friction experiments involving copper and Cu-Be alloy plates in contact with copper, Cu-Be alloy, steel and titanium alloy sliders were performed in air and vacuum. Micro-hardness and metallographic examination of plate and slider interface suggests friction and wear by the adhesive friction mechanism with prow formation. Transfer of strain-hardened metal wear debris across the sliding interface leas observed. The friction coefficient and the prow size generally increased in vacuum.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Atlantic City, New Jersey. October 8–10. 1968.

ISSN:0569-8197    

DOI:10.1080/05698196908972259

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor