摘要:

AbstractThe design and operation of two closely‐related pieces of apparatus which allow the acquisition of Raman spectra from lubricant fluids ‘in lubro’ in an elastohydrodynamic contact are reported. Spectroscopic sensitivity was not sufficient to allow a detailed structural interpretation of the spectra under these extreme conditions. However, the systems have been used in a novel way to obtain profiles and maps of the pressure distribution, as experienced by the fluid in the working elastohydrodynamic co

ISSN:0954-0075    

DOI:10.1002/ls.3010010402

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractIn fatigue tests of plain carbon steel specimens in air, fatigue life is taken up mainly by the life in which a crack propagates from its initial size up to about 1 mm. This means that the behaviour of a small crack in the oil environment must be known in order to evaluate the effect of oils on fatigue life.In this paper, using a series of base oils of different viscosity grades, the effects of oils on fatigue damage are investigated in rotating bending fatigue tests of annealed 0.34% carbon steel plain specimens. Successive detailed observations of the specimen surface are made in order to study the fatigue processes of micro‐crack initiation and small crack propagation. The physical background of the effect of oil environments on fatigue behaviour is shown, and a method for predicting fatigue life in oil environments is discusse

ISSN:0954-0075    

DOI:10.1002/ls.3010010403

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractEngine oil additives generally fall into one of two general categories: those that affect bulk oil properties and those that affect the surface properties of lubricated parts. Interactions among surface‐active additives can lead to less‐than‐expected lubricant performance. Laboratory friction and wear test results are presented to illustrate the changes in lubricant performance that interactions among additives can cause. Some possible explanations are pro

ISSN:0954-0075    

DOI:10.1002/ls.3010010404

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractPreventing valve train wear in automotive engines is one of the most important properties of an engine oil. However, the influence of engine oil additives on valve train wear has not been sufficiently clarified.In this investigation, the antiwear performance of additives (such as ashless dispersants, metallic detergents and zinc dithiophosphate ‐ ZDTP) and the influence of the interaction of the additives were evaluated.Secondly, metallic detergents were considered. An overbased calcium sulphonate and an overbased phenate were found to have good anti‐scuffing performance when evaluated in engine tests and in Falex wear tests. However, from the results of four‐ball tests, these additives did not appear to have many extreme pressure properties. From surface analyses, it was determined that a calcium carbonate film was formed on the sliding surface of the Falex test piece, and this film provided good protection against wear.Finally, the interaction of ZDTP, succinimides and calcium detergents and their influence on valve train wear were studied. The decomosition temperature of ZDTP increased with certain additives. including the succinimide. As a result, scuffing was more prone, at temperatures below those increased temperatures. Also, changes in additive concentration on the sliding surface, due to competitive adsorption, altered the antiwear performance of th

ISSN:0954-0075    

DOI:10.1002/ls.3010010405

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThis paper is presented as an introduction to various specific problems associated with metalworking additives, especially that related to their modes of action. It describes various chemicals used as specific additives for metalworking lubricants. The introductory part of the review deals with general lubricant types for both metal‐forming and metal‐cutting processes. The section dealing with types of additives used for metalworking lubricants is followed by a section on the chemistry of these additives. The detailed review is connected with boundary lubrication additives for water‐based liquids and oil‐based lubricants. Corrosion and antimicrobial agents are discussed as well. Other additives are described more ge

ISSN:0954-0075    

DOI:10.1002/ls.3010010406

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0954-0075    

DOI:10.1002/ls.3010010401

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY