摘要:

This paper discusses piston ring wear data obtained from operating a single cylinder internal-combustion engine fitted with an irradiated standard chromium plated top compression ring. A brief description of the engine equipment, the constantly-monitored lubricating oil flow system, the dual-channel gamma spectrometer and an outline of test method are included. The author stresses the development of a technique which permits a separate simultaneous record of the wear occurring on the face and on the side of the radioactive piston ring. Results are presented from constant speed engine operation with a series of different lubricating oil additive formulations.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Toronto, Canada, October, 1957.

ISSN:0569-8197    

DOI:10.1080/05698195808972318

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

The occurrence of galling when unlubricated surfaces are slid together is shown through an energy balance to he determined by the parameter WKcot θ/p, where WKis the work of adhesion of the system, θ the average slope of the surface, and p the flow pressure of the softer metal. For lubricated surfaces, it is shown that only lubricants made up of very small molecules can be energetically stable on hard metal surfaces, and hence successful lubricants must form solid surface films. At the melting point of the lubricant film a transition takes place and the lubricant loses much of its effectiveness, while a second transition occurs at a higher temperature and leads to galling. This second transition is caused by desorption of the lubricant accompanied by a rise in WKbut varies widely for different metals, being influenced by their flow pressure.Contributed by the ASLE Technical Committee on Lubrication Fundamentals and presented at the Annual Meeting of the American Society of Lubrication Engineers held in Detroit, Michigan, April 1957.

ISSN:0569-8197    

DOI:10.1080/05698195808972319

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

An experimental study of the role of oxidation due to frictional heating in unlubricated high speed (13000 ft/min) sliding of metals is discussed. Detailed results for steel on steel have been described in another paper (1). This paper discusses a general picture correlating the results for several metal combinations and also a bonded metal carbide. The results indicate that the oxidation gives considerable protection against surface damage. With copper on copper (previously run-in), copper on steel, and bonded tungsten carbide on bonded carbide relatively little tearing of the metal (or carbide) is observed at light loads. The oxidation should increase with increasing load, and these combinations behave like steel on steel in that on at least one of the surfaces there is, if anything, even less metallic tearing at high load. At low loads wear is mild, in harmony with the oxide protection, but at higher loads severe wear is attributed to disintegration within the oxide itself. With nickel on nickel the oxidation fails to prevent fairly severe metallic tearing even at high loads. Some consequences of these phenomena in the variation of friction, wear and surface damage with load, speed and sample geometry are described.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Toronto, Canada, October, 1957.

ISSN:0569-8197    

DOI:10.1080/05698195808972320

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Some experiments are reported on the sliding behavior of synthetic sapphire against certain fairly pure metals as a function of temperature. The initial selection of the sapphire-metal couple was determined on the basis of thermodynamic and physical consideration so as to produce, theoretically, a weak interfacial contact, region. It was observed that this basis for selection of desirable sapphire-metal couples needed to be modified to include the effect of the surrounding atmosphere. For example, the couple sapphire-nickel should exhibit theoretically a low wear rate, weak adhesion and low friction. It was found, however, that the adhesion effects for this couple were highly sensitive to the presence of oxygen, and unless the oxygen was completely excluded, high friction and metal transfer occurred. The couple sapphire-gold, on the other hand, exhibited low friction and metal transfer regardless of atmosphere and elevated temperature. Hence, it would appear that the resistance to oxide formation by the metal is an important criterion for good sliding characteristics in metal-ceramics couples in sliding contact.

ISSN:0569-8197    

DOI:10.1080/05698195808972321

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Most carbon-type seal materials contain graphitic carbon as the minor constituent. Materials having graphite carbon as the major constituent were studied as possible seal materials at 10,000 feet per minute sliding velocities, in most experiments the temperature of the mating surfaces was 500°F. Carbon materials made graphitic by electro-graphitization were too soft; they gave high wear and high friction. Bodies molded with high-graphite-content materials and made hard by improved molding methods and impregnation gave acceptable friction and wear properties.

ISSN:0569-8197    

DOI:10.1080/05698195808972322

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

The behavior of several solid film lubricants has been experimentally established as a function of temperature. These films are formed of a suspension of lubricant particles (graphite, molybdenum disulfide) in a thermosetting resin baked onto a hard surface. The test consists of heating such a layer and continually observing the friction coefficient until failure. Sliding conditions of high unit loading and low rubbing velocity were chosen to provide a comparison between the films. They were evaluated as to the highest temperature for which the friction coefficient remained low and subsequently as to the number of load cycles sustained at temperature before an abrupt increase in friction. Results for all films were similar in that failure was caused by a breakdown of the binder rather than the lubricating particles and that the minimum friction coefficient (∼ 0.03) was observed just before the film failure at temperatures as high as 1200° F.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Toronto, Canada, October, 1957.

ISSN:0569-8197    

DOI:10.1080/05698195808972323

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

The conventional model of orthogonal cutting with type 2 chip is modified to include the effect of deformation of the work-piece at the immediate vicinity of the tool-tip. The cutting velocity condition for optimal force of deformation is examined in the light of two alternate criteria: recrystallization temperature and melting temperature. It is shown that a critical cutting velocity exists. Furthermore, it is concluded, in part, that proper metallurgical treatment and/or preheating the work-piece (hot machining) will improve cutting.Contributed by the ASLE Technical Committee on Lubrication Fundamentals and presented at the Annual Meeting of the American Society of Lubrication Engineers held in Pittsburgh, Pa. April 1956.

ISSN:0569-8197    

DOI:10.1080/05698195808972324

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

The initiating step in cutting-tool wear is postulated as a temperature-dependent migration of chip metal into the tool. The migrated metal softens the tool, which allows wear particles to adhere to the moving chip and be carried away. The kinetics of these processes are developed quantitatively to yield an expression which explains the Taylor equation in terms of the fundamental parameters of cutting. The action of cutting-oils is regarded as a competition between the rate of alloying and softening of the tool by migrated chip metal and the rate of reaction of the migrated chip metal with the cutting-oil additive. The kinetics of these competing processes are then developed quantitatively to explain the behavior of the Taylor equation when metal is cut in the presence of cutting-oil.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Toronto, Canada, October, 1957.

ISSN:0569-8197    

DOI:10.1080/05698195808972325

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

Various material combinations are investigated in the form of thrust bearings in such fluids as sodium-potassium eutectic, xylene and spindle oil. It is found that with these fluids certain material combinations can be made to perform satisfactorily as hydrodynamic bearings by a process of wearing-in. With these unique combinations it is possible to obtain film thicknesses of the order of 10 × 10−6inches by extreme wear-in. The characteristics of bearings worn in to this degree are reported and mechanisms for the observed effects discussed.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Toronto, Canada, October, 1957.

ISSN:0569-8197    

DOI:10.1080/05698195808972326

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor

摘要:

An investigation was conducted to determine the friction and oil feed characteristics of the cotton waste pack used for railroad journal bearing lubrication. The investigation also included wool and nylon fiber materials. An apparatus was constructed in which the pressure force between the waste pack and journal could be controlled and measured and the journal friction torque determined. A scraping technique was devised to measure the oil film thickness on the journal.

ISSN:0569-8197    

DOI:10.1080/05698195808972327

出版商:Taylor & Francis Group    

年代:1958

数据来源: Taylor