摘要:

A single-element traction rig was used to measure the traction forces at a solid-lubricated contact of a ball against a flat disk at room temperature under combine rolling and sliding. The load and speed conditions were selected to match those anticipated for bearing applications in adiabatic diesel engines. Traction vs slide/roll ratio curves were similar to those for liquid lubricants but the traction forces were an order of magnitude higher. The test data were used to derive equations to predict traction force as a function of contact stress and rolling speed. The data showed that the magnitude of traction forces were almost the same for all the lubricants tested. The lubricants, should, therefore, be selected on the basis of their ability to limit the wear of contact surfaces.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981678

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Solid-lubricated ball bearing life is limited by several failure modes that normally do not present a significant risk to liquid-lubricated bearings. While conventional subsurface fatigue failure is normally considered to be the primary limiting factor of life in liquid-lubricated ball bearing, other failure modes must be evaluated in assessing the life of solid-lubricated bearings. A quasi-empirical method for assessing life and reliability of solid-lubricated bearings was developed that considers: (1) fatigue, (2) raceway wear, (3) ball separator wear, and (4) lubricant transfer rate control from sacrificial self-lubricating ball separators.

ISSN:0569-8197    

DOI:10.1080/05698198608981679

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Graphite-fiber-reinforced polyimide (GFRPI) composites were formulated form three new partially fluorinated polyimides and three types of graphite fiber. Nine composites were molded into pins and evaluated in a pin-on-disk tribometer. Friction coefficients, wear rates, pin wear surface morphology, and transfer film formation were assessed at 25 and 300°C. Also assessed was the effect of sliding distance on friction and the effect of constantly increasing or decreasing temperature on friction. Wear was up to two orders of magnitude lower at 25°C and up to one order of magnitude lower at 300°C than with previously formulated NASA GFRPI composites.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981680

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This paper presents an experimental study made on physical-vapor-deposited (PVD) silver films. A conventional ion plating unit was used in depositing ion-plated, vacuum-deposited, and gas-deposited silver films.

ISSN:0569-8197    

DOI:10.1080/05698198608981681

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Vapor phase lubrication has been demonstrated using a conventional four-ball wear Lester run at 370°C using M50 hot hardness steel ball bearings. The four-ball wear tester was modified to control both the temperature and the environment surrounding the ball pot and spindle. The lubricant in all cases comprised a homogeneous gas phase mixture of nitrogen and phosphate ester vapors. The two phosphate esters used were tributyl phosphate (TBP) and tricresyl phosphate (TCP). The volume percent phosphate ester vapor in nitrogen ranged from 0.10 to 6.0 percent. The minimum temperature of the four balls was maintained at 370°C which was always at least 50°C higher than the temperature of the homogeneous vapors delivered so that there was no possibility of vapor condensation on the wear contacts.

ISSN:0569-8197    

DOI:10.1080/05698198608981682

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Several developments have been made in mass spectrometry during the last few years. One of the most significant developments, fast-atom bombardment mass spectrometry, has tremendous potential for the characterization of lubricants. The technique is described, and examples of its use for the direct, rapid, and semiquantitative characterization of synthetic base oils and additives in lubricants are given.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981683

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

To reduce the transmission of impact energy in a drop forge from the impacting die to the anvil while retaining the deformation efficiency, a double-pad oil film has been developed and tested.

ISSN:0569-8197    

DOI:10.1080/05698198608981684

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The erosion of low-carbon steel, in the annealed and water-quenched condition, by coal particles, has been studied as a function of particle size, velocity, and angle of impingement. It was found that both unicrostructures, pearlitic and martensitic, showed a maximum erosion at an angle of impingement of between 20 and 30°. Under all condition of testing, the martensitic structure showed the higher rate of erosion. The coal particles were found to fracture on impact with the steel surfaces. The amount of fracture was found to increase will increased velocity and particle size. Erosion rate was found to increase with decreasing particle size and was related to particle velocity (V) through a power law relationship of the form: E = kVn, where the exponent (n) has valves between 2.6 and 3.7. Scanning electron microscopy studies indicated that only the harder mineral constituents in the coal, such as pyrite and quartz, were responsible for the erosion of the steel.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–8, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981685

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This paper describes the analysis, design, and experimental evaluation of a new bearing concept for grinding mills. This concept was applied to 11 m (36 ft) diameter autogeneous mills which were the largest mills worldwide at the time of their installation.

ISSN:0569-8197    

DOI:10.1080/05698198608981686

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Contact angle measurements were performed for a five-ring polyphenyl ether isomeric mixture on M-50 steel in a dry nitrogen atmosphere. Two different techniques were used: (1) a tilting-plate apparatus, and (2) a sessile drop apparatus. Measurements were made for the temperature range 25 to 190°C. Surface tension was measured by a differential maximum bubble pressure technique over the range 23 to 220°C in room air. The critical surface energy of spreading (γc) was determined for the polyphenyl ether by plotting the cosine of the contact angle (θ) versus the surface tension (γLV). The straight line intercept at cos θ = 1 is defined as γc. γcwas found to be 30.1 dyn/cm for the tilting-plate technique and 31.3 dyn/cm for the sessile drop technique. These results indicate that the polyphenyl ether is inherently autophobic (i.e., it will not spread on its own surface film until its surface tension is less than γc). This phenomenon is discussed in light of the wettability and wear problems encountered with this fluid.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981687

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor