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mixed-film lubrication

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Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390173
EISBN: 978-1-62708-459-8
... the friction and wear that occur in hot and cold rolling under hydrodynamic and mixed-film lubrication; the influence of viscosity, film thickness, rolling speed, interface pressure, pass reduction, and lubricant breakdown; and the effect of surface finish and defects. The chapter also provides best practices...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390241
EISBN: 978-1-62708-459-8
..., heat, strain, and distortion for different tooling configurations and geometries. It explains how to select and apply lubricants based on drawing speed, die design, and other factors and how to maintain sufficient film thickness for hydrodynamic, mixed, and solid-film lubrication conditions. It also...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390064
EISBN: 978-1-62708-459-8
... and fluid film regimes. Mixed lubrication is common in metal forming, because of the combined benefits of low friction and wear, and good control of surface finish ( Fig. 3.9 ). In mixed lubrication, 1 ≤ λ ≤ 3, and typical friction coefficient values are μ = 0.01 to 0.15. Hydrodynamic lubrication...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2012
DOI: 10.31399/asm.tb.smff.t53400089
EISBN: 978-1-62708-316-4
... lubrication Mixed-film lubrication Hydrodynamic lubrication As shown in Fig. 7.2 , the Stribeck curve illustrates schematically the onset of various types of lubrication mechanisms as a function of lubricant viscosity, η, sliding velocity, v , and normal pressure, p ( Ref 7.1 ). Fig. 7.2...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390145
EISBN: 978-1-62708-459-8
... discussions it is obvious that, for some variables, no compromise can be made at all: (a) The film parameter is often of paramount importance. Surface roughness greatly affects the formation of lubricant films and determines the amount of asperity contact in the mixed-film regime. Therefore...
Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390100
EISBN: 978-1-62708-459-8
... important when the process encourages hydrodynamic lubrication. When oils operate in the mixed-film regime, it is often difficult to determine whether or not the presence of a longer-chain fatty acid constituent improves boundary lubrication. Unsaturated compounds containing double or triple bonds ( drying...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390284
EISBN: 978-1-62708-459-8
... forms, and this angle increases with reduction ratio. It is essential, though, that no trace of a lubricant or contaminant film be present on the billet surface, because otherwise the sticking condition will be locally disturbed and the lubricant will be washed in below the product surface. This can...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390325
EISBN: 978-1-62708-459-8
... conditions over the entire interface. In contrast, in plane-strain compression, the deforming material flows out from between the anvils and in doing so carries with it a lubricant film ( Fig. 7.3c ). Thus full- or mixed-film lubrication can be maintained right up to the edge of the anvil, where...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 February 2005
DOI: 10.31399/asm.tb.chffa.t51040067
EISBN: 978-1-62708-300-3
.... Boundary Lubrication Boundary lubrication is governed by thin films (typically organic) physically adsorbed or chemically adhered to the metal surface. These films provide a barrier under conditions of large metal-to-metal contact where the properties of the bulk lubricant have no effect...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390039
EISBN: 978-1-62708-459-8
..., mainly due to workpiece surface roughening that would result ( Sec. 3.2 ). Therefore, in manufacturing, lubrication is mostly of the mixed-film or boundary type ( Sec. 5.2 ), and some reactions with the metal surface are not only tolerated but encouraged. In the course of sliding, some reaction products...
Series: ASM Technical Books
Publisher: ASM International
Published: 30 April 2021
DOI: 10.31399/asm.tb.tpsfwea.t59300391
EISBN: 978-1-62708-323-2
... and friction control, the relationship between viscosity and breakaway friction, and the factors that affect load-carrying capacity and service life. friction control industrial greases liquid lubricants solid-film lubricants DUNCAN DOWSON, a distinguished professor at the University...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390389
EISBN: 978-1-62708-459-8
... the free extension of the wall, but elastic springback helps to relieve the pressures and reduces friction. Liquid lubrication is generally of the mixed-film type, so that boundary and extreme pressure additives are essential. A rougher surface, indicative of hydrodynamic lubrication, is formed...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390019
EISBN: 978-1-62708-459-8
... a dull or matte appearance on a surface, often characterized by the surface gloss , or fraction of incident light reflected. The lubricant film thickness (see Sec. 5.2 ) is important in determining roughening behavior ( Fig. 3.9 ). With smooth tooling and boundary or mixed lubricant films...
Series: ASM Technical Books
Publisher: ASM International
Published: 30 April 2021
DOI: 10.31399/asm.tb.tpsfwea.t59300013
EISBN: 978-1-62708-323-2
... look like Fig. 2.1 . Fig. 2.1 A friction force recording illustrating stick-slip behavior Squeals from tribosystems are often due to stick-slip behavior between contacting surfaces. Separating films or changes in the sliding conditions (speed, force, lubrication) can alter or eliminate...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2000
DOI: 10.31399/asm.tb.ttg2.t61120085
EISBN: 978-1-62708-269-3
... of these films are less effective. Lubricant films or abrasion-protective films are applied over a silica-base coating. This process has the advantage of providing double protection against scratching and scoring. During hot forming operations and metal surface stretching, some voiding and penetration...
Series: ASM Technical Books
Publisher: ASM International
Published: 30 April 2021
DOI: 10.31399/asm.tb.tpsfwea.t59300047
EISBN: 978-1-62708-323-2
... in some way with lubricants; this section will also concentrate on the friction aspects of lubricated tribosystems. Fig. 3.12 Types of lubricants Solid film lubricants are just that—a film of some solid substance is deposited on a sliding or rolling surface in order to reduce friction...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2001
DOI: 10.31399/asm.tb.secwr.t68350043
EISBN: 978-1-62708-315-7
... are forced to move relative to each other. It is closely associated with any wear mechanisms that may be operating and with any lubricant and/or surface films that may be present, as well as the surface topographies. The heat generated as a result of the dissipation of frictional interaction may affect...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2003
DOI: 10.31399/asm.tb.cfap.t69780267
EISBN: 978-1-62708-281-5
... to estimate the film thickness of the lubricant for elastomer pressed against a metal ( Ref 41 – 43 ). The other example of the use of polymers in a lubricating environment is that of the knee/hip joint replacement using UHMWPE ( Ref 44 , 45 ). UHMWPE is widely used in making acetabular sockets for hip...
Series: ASM Technical Books
Publisher: ASM International
Published: 30 April 2021
DOI: 10.31399/asm.tb.tpsfwea.t59300079
EISBN: 978-1-62708-323-2
... rubbing surfaces. Of course, lubrication that effectively separates the rubbing surfaces mitigates the adhesive interactions. However, surface contact still occurs at start-up and shutdown of lubricated tribosystems. Full film separation of surfaces requires a critical sliding velocity (per Stribeck...
Series: ASM Technical Books
Publisher: ASM International
Published: 30 September 2023
DOI: 10.31399/asm.tb.stmflw.t59390001
EISBN: 978-1-62708-459-8
... were probably not too different from those found some fifty years ago, with sawdust, a thin smear of a heavy oil, or oil mixed with graphite serving as a lubricant. 1.1.2 Wire Drawing The argument on the earliest date of wire drawing is still not settled. Theophilus, the German monk writing...