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boundary lubrication

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Published: 01 January 2002
Fig. 1 Schematic of the transition from inadequate (boundary) lubrication at start-up to hydrodynamic lubrication at full speed. (a) Steady load at start-up. (b) Steady load at full speed More
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Published: 30 August 2021
Fig. 4 Schematic of the transition from (a) inadequate (boundary) lubrication at startup to (b) hydrodynamic lubrication at full speed, h is minimum separation More
Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006806
EISBN: 978-1-62708-329-4
... provides an overview of bearing materials, and then presents the various lubrication mechanisms: hydrostatic, hydrodynamic, boundary lubrication, elastohydrodynamic, and squeeze-film lubrication. The article describes the effect of debris and contaminant particles in bearings. The steps involved in failure...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.mech.c0009190
EISBN: 978-1-62708-225-9
... occurs low on the pinion tooth near the lowest point of single-tooth contact (LPSTC), where h min is 0.053 pm (2.1 pin.). The specific film thickness, based on R q of 0.5 pm (20 pin.) for both profiles, is X = 0.073. Figure shows that the gears operate in the boundary lubrication regime...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006789
EISBN: 978-1-62708-295-2
..., and contact fatigue damage is by spalling, because the maximum stress is in the subsurface region. When Λ is low, mixed or boundary lubrication is present, and contact fatigue damage is by pitting, because friction shifts the maximum contact stress toward the surface. In spalling, the fatigue life is higher...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c9001717
EISBN: 978-1-62708-217-4
... thermal treatment. These large grains offered less resistance to fatigue and SCC. In addition, evidence of titanium-carbo-nitrides was detected at the grain boundaries of this material that was prohibited according to the governing specification. This phase is formed at higher thermal treatment...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003524
EISBN: 978-1-62708-180-1
... mechanics fracture modes fracture surface lubricants macroscopic examination mechanical testing microscopic examination nondestructive inspection sampling simulated-service testing stress analysis wear failure ANALYZING the inevitable failures that occur during testing, manufacturing...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006791
EISBN: 978-1-62708-295-2
... and contacts operating in the mixed- and boundary-lubrication regimes, due to insufficient lubrication supply, inadequate viscosity, incorrect internal clearances, incorrect installation, or misalignment. Adhesive wear also can cause rapid and sometimes catastrophic failures ( Ref 2 ). This can occur in metal...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0001809
EISBN: 978-1-62708-180-1
...) , with a minimum separation h. The fluid-film pressure builds behind the location of minimum separation between the shaft and bearing, taking the shaft surface as the reference. Fig. 1 Schematic of the transition from inadequate (boundary) lubrication at start-up to hydrodynamic lubrication at full speed...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006911
EISBN: 978-1-62708-395-9
... to dominate over contact forces. There are three major lubrication regimes which describe the lubricated sliding surface interactions: boundary lubrication, mixed lubrication, and hydrodynamic lubrication ( Ref 11 ). In boundary lubrication ( Fig. 4 ), asperities on the sliding interface are fully...
Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006834
EISBN: 978-1-62708-329-4
... losses ≥1 Fluid if extremely clean and no other influences Pollution? Temperature? Environment? 0.4 ≥ κ > 1 Mixed lubrication Pollution? Temperature? Environment? Additives? Aging of the medium and chemical life of the lubricant? <0.1 Boundary lubrication Severe wear For κ...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001783
EISBN: 978-1-62708-241-9
... of Lubrication an Tribology . Vol 1 : Application and Maintenance, 2nd edn. CRC Press , Boca Raton ( 2006 ) 12. Sullivan J.L. , Wong L.F. : Wear of aluminium bronze on steel under conditions of boundary lubrication . Tribol. Int. 18 , 275 – 281 ( 1985 ) 10.1016/0301-679X(85)90106-9...
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001836
EISBN: 978-1-62708-241-9
... in the crack vicinity. After etching the sample, the presence of copper is observed at the grain boundary. This shows the possibility of copper diffusion during pipe bending at high temperature ( Fig. 2 ). Fig. 2 Microphotographs of cracks in unetched and etched conditions SEM–EDS Analysis...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.rail.c9001719
EISBN: 978-1-62708-231-0
... detailing intergranular fracture with copper wetting the surface support this conclusion. Historical evidence that has examined failures of this type has supported similar conclusions. The bronze friction bearing melts when the lubrication has failed and liquid copper penetrates at the grain boundaries...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003565
EISBN: 978-1-62708-180-1
... with lubrication, it is probable that asperity contact will be frequent, except for combinations of low-contact pressure, high-viscosity oils, and low surface roughness. It is likely, therefore, that the contact will be boundary lubricated, in which case the surface shear stresses will not differ substantially...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0001822
EISBN: 978-1-62708-180-1
... the surface inward, the fracture surface was rough, indicating the depth of copper penetration. The central portion was smooth, indicative of a fatigue fracture that ultimately led to failure. Color photomicrographs revealed a yellow grain-boundary copper phase. It was pointed out that adequate lubrication...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.chem.c9001408
EISBN: 978-1-62708-220-4
... in temperature. The material was a steel in the normalized condition with a 0.35% C content. It appears probable that deficient lubrication of the gland resulted in overheating of the rod due to friction. The presence of a sprayed-metal coating was probably an additional factor in promoting failure, as it would...
Series: ASM Failure Analysis Case Histories
Volume: 2
Publisher: ASM International
Published: 01 December 1993
DOI: 10.31399/asm.fach.v02.c9001335
EISBN: 978-1-62708-215-0
... performed on an embrittled section and on a section from a different lot that did not crack during forming. The failed section showed an intergranular fracture path. Examination of the fracture surfaces revealed the presence of tellurium at the grain boundaries. The source of the tellurium was thought...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.power.c9001620
EISBN: 978-1-62708-229-7
... revealed finely spaced striations on the crack surfaces, supporting a diagnosis of fatigue cracking. Crack initiation in the pulverizer shafts started as a result of fretting fatigue. Greater attention to lubrication was suggested, combined with asking the manufacturer to consider nitriding the splined...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006793
EISBN: 978-1-62708-295-2
... of low-contact-pressure, high-viscosity oils and low surface roughness. It is likely, therefore, that the contact will be boundary lubricated, in which case the surface shear stresses will not differ substantially from the dry case. Thus, a boundary-lubricated, normal-impact contact is essentially quasi...