Effect on lubrication regimes with silicon nitride and bearing steel balls

2017 ◽  
Vol 116 ◽  
pp. 403-413 ◽  
Author(s):  
Muthunilavan N. ◽  
Rajaram G.
Keyword(s):  
Silicon Nitride ◽  
Bearing Steel ◽  
Lubrication Regimes ◽  
Steel Balls

scholarly journals Fatigue Life of High-Speed Ball Bearings With Silicon Nitride Balls

1975 ◽  
Vol 97 (3) ◽  
pp. 350-355 ◽  
Author(s):  
R. J. Parker ◽  
E. V. Zaretsky
Keyword(s):  
Fatigue Life ◽  
Silicon Nitride ◽  
High Speed ◽  
Bearing Steel ◽  
Rolling Element Bearing ◽  
Ball Bearings ◽  
Rolling Element ◽  
Low Mass ◽  
Element Bearing ◽  
Steel Balls

Hot-pressed silicon nitride was evaluated as a rolling-element bearing material. This material has a low specific gravity (41 percent that of bearing steel) and has a potential application as low mass balls for very high-speed ball bearings. The five-ball fatigue tester was used to test 12.7-mm- (0.500-in-) dia silicon nitride balls at maximum Hertz stresses ranging from 4.27 × 109 N/m2 (620,000 psi) to 6.21 × 109 N/m2 (900,000 psi) at a race temperature of 328K (130 deg F). The fatigue life of NC-132 hot-pressed silicon nitride was found to be equal to typical bearing steels and much greater than other ceramic or cermet materials at the same stress levels. A digital computer program was used to predict the fatigue life of 120-mm- bore angular-contact ball bearings containing either steel or silicon nitride balls. The analysis indicates that there is no improvement in the lives of bearings of the same geometry operating at DN values from 2 to 4 million where silicon nitride balls are used in place of steel balls.

Effects of structural inhomogeneities on the steel balls resistance to loading

2020 ◽  
pp. 29-38
Author(s):  
O. B. Berdnik ◽  
I. N. Tsareva ◽  
L. A. Krivina ◽  
S. V. Kirikov ◽  
S. I. Gerasimov ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Bearing Steel ◽  
Metallographic Analysis ◽  
Structural Factors ◽  
Steel Shkh15 ◽  
Maximum Hardness ◽  
High Shock ◽  
Steel Balls ◽  
Plasticity Coefficient ◽  
Microstructure Of The Material

When conducting impact tests of protective glasses, nonunique cases of destruction of balls made of bearing steel ShKh15 were recorded. The causes of their destruction were determined. The state of the material was studied by fractographic and metallographic analysis, hardness and microhardness measurement. In the structure of the metal of all the balls, no critical defects were found such as flockens, shells and microcracks, but adverse factors were detected in the microstructure of the material, namely, the presence of fineneedle martensite with excessive carbides. It is established that the detected structural factors lead to liability to brittle fracture, an increase in the hardness of the material, a decrease in plasticity. To prevent brittle fracture of the balls and provide a reserve of plasticity of steel ShKh15 at high shock loads assessment calculations of ductility coefficient were made; and it was recommended to limit the maximum hardness of the material critical value HV=5.70 HPa (54 HRC), with the corresponding plasticity coefficient equal to 0.8.

Friction Torque Measurement in Partial Hybrid S-C Angular Contact Ball Bearings

2014 ◽  
Vol 658 ◽  
pp. 339-344
Author(s):  
Viorel Paleu ◽  
Ioan Damian ◽  
Cristel Stirbu
Keyword(s):  
Silicon Nitride ◽  
High Speed ◽  
Equilibrium Temperature ◽  
Friction Torque ◽  
Ball Bearings ◽  
Self Healing ◽  
Testing Device ◽  
Torque Measurement ◽  
Steel Balls ◽  
Partial Hybrid

To monitor the friction torque evolution in tandems of angular contact ball bearings, a new testing device is developed. New partial hybrid bearings from 7206C series are obtained by combining 8 steel balls with 4 silicon nitride balls of the same diameter equally spaced in the cage, these bearings being denoted hereafter as 8S-4C type. For comparison, tests are carried-out also on conventional all-steel bearings and hybrid bearings with all the steel balls replaced by silicon nitride balls. The equilibrium temperature of the all-steel, hybrid and 8S-4C ball bearings is determined by tests. At high speed and light axial load, the 8S-4C ball bearings withstand to an oil shut-off test of one minute, while the similar all-steel bearings seized. The 8S-4C partial hybrid ball bearings can be an advantageous solution comparative to more expensive all hybrid bearings, avoiding the scuffing due to the self-healing effect induced by the higher hardness of the silicon nitride balls.

scholarly journals TiC/a-C Nanocomposite Coatings for Low Friction and Wear Resistance

2005 ◽  
Vol 475-479 ◽  
pp. 3655-3660 ◽  
Author(s):  
Y.T. Pei ◽  
Damiano Galvan ◽  
Jeff T.M. de Hosson
Keyword(s):  
Wear Resistance ◽  
Friction And Wear ◽  
Ambient Air ◽  
Bearing Steel ◽  
Nanocomposite Coatings ◽  
Columnar Microstructure ◽  
Low Friction ◽  
Micro Cracks ◽  
Steel Balls ◽  
Wear Tests

TiC/a-C:H nanocomposite coatings have been deposited by magnetron sputtering and are composed of 2-5nm TiC nanocrystallites well separated by amorphous hydrocarbon (a-C:H) of about 2nm separation width. A transition from columnar to glassy microstructure has been observed with increasing substrate bias or carbon content. Micro-cracks induced by nanoindentation or wear tests readily propagate through the column boundaries whereas the coatings without a columnar microstructure show supertough behavior. The nanocomposite coatings exhibit hardness of 5~20 GPa, superior wear resistance and strong self-lubrication effects with a friction coefficient of 0.05 in air and 0.01 in nitrogen under dry sliding against uncoated bearing steel balls. Especially, the transitions from low to ultralow friction or the reverse are repeatedly switchable if the atmosphere is cycled between ambient air and nitrogen. The lowest wear rate is obtained at high humidity.

Wear mechanisms in oil-lubricated and dry fretting of silicon nitride against bearing steel contacts

Wear ◽  
1997 ◽  
Vol 210 (1-2) ◽  
pp. 27-38 ◽  
Author(s):  
M. Kalin ◽  
J. Vižintin ◽  
S. Novak ◽  
G. Dražič
Keyword(s):  
Silicon Nitride ◽  
Wear Mechanisms ◽  
Bearing Steel

Investigation of the wear of engine journal bearings approaching severe lubrication conditions using a microabrasion tester

2019 ◽  
Vol 233 (12) ◽  
pp. 1939-1949 ◽  
Author(s):  
Andys Hernández-Peña ◽  
Leonardo I Farfan-Cabrera ◽  
Ezequiel A Gallardo-Hernández
Keyword(s):  
Boundary Lubrication ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Mineral Oil ◽  
Constant Load ◽  
Journal Bearings ◽  
Engine Operation ◽  
Lubrication Regimes ◽  
Actual Use ◽  
Steel Balls

Ideally, engine journal bearings are expected to operate under hydrodynamic lubrication regime to limit wear and promote minimal friction by sliding. Nevertheless, engine journal bearings fail since wear caused by severe conditions in actual engine operation, such as start/stop, misalignment, lubricant degradation, overheating, and debris contamination, producing a transition from hydrodynamic to mixed and boundary lubrication regimes and wear increased in both engine journal bearings and crankshaft. Thus, this work aims to study the influence of boundary lubrication, engine mineral oil aging, and debris contamination on wear of engine journal bearings. An adapted microscale abrasion tester using a ball-on-concave flat configuration was used to reproduce boundary lubrication under controlled conditions. Steel balls having a similar surface than crankshafts and concave flat samples cut from actual engine journal bearings were tested. The tests were run under boundary lubrication at a constant load, speed, and sliding distance at 26 ℃ and 100 ℃ using separately clean fresh and aged engine mineral oil, and then, tests were conducted using the oils contaminated with hard abrasive particles. The engine mineral oil was degraded by a laboratory aging process approaching oxidation of an engine mineral oil used in actual use conditions. Oxidation, additives depletion and changes in viscosity were evaluated. The wear volumes and scar morphologies of engine journal bearing samples were analyzed. The results suggested that high temperature was the main contributor for wear increase in engine journal bearings, while oil aging and debris did not influence considerably on the wear. However, the oils contaminated with hard particles produced a wear decrease in engine journal bearing samples but increased wear in rotary balls.

Comparative Study on the Tribological Performance of HFCVD Diamond and DLC Films under Water Lubricating Condition

2011 ◽  
Vol 487 ◽  
pp. 155-159
Author(s):  
Bin Shen ◽  
Fang Hong Sun ◽  
Zhi Ming Zhang
Keyword(s):  
Silicon Nitride ◽  
Friction Coefficient ◽  
Tungsten Carbide ◽  
Ball Bearing ◽  
Arc Discharge ◽  
Bearing Steel ◽  
Tribological Performance ◽  
Vacuum Arc ◽  
Dlc Film ◽  
Ball Bearing Steel

The tribological performance of conventional microcrystalline diamond (MCD) film and diamond-like carbon (DLC) film is investigated comparatively under water lubricating condition. The MCD and DLC film are deposited on cobalt cemented tungsten carbide (WC-Co) substrate using the hot filament chemical vapor deposition (HFCVD) method and the vacuum arc discharge with a graphite cathode respectively. Scanning electron microscopy (SEM), white light interferometer, and Raman spectra are employed to characterize as-deposited MCD and DLC samples. The friction tests are carried out on a ball-on-plate reciprocating friction tester, where the sliding process is conducted under water lubricating condition. Silicon nitride, tungsten carbide, ball-bearing steel and copper are used as counterpart materials. The results indicate that DLC film always exhibits lower friction coefficient than MCD film under water lubricating condition, except the case of sliding against the silicon nitride, in which DLC film is worn out very rapidly and thus leads to the high friction coefficient. The wear resistance of DLC film under water lubricating condition is significantly poorer than that of MCD film. While sliding against silicon nitride, tungsten carbide, ball-bearing steel and copper, its wear rate is calculated as 3.67´10-7mm3N-1m-1, 9.31´10-9mm3N-1m-1, 3.54´10-7mm3N-1m-1, and 4.97´10-8mm3N-1m-1respectively. Comparatively, no measurable wear track can be found on the worn surface of MCD films.

Wear Mechanism of Ceramic Materials in Dry Rolling Friction

1986 ◽  
Vol 108 (4) ◽  
pp. 522-526 ◽  
Author(s):  
S. S. Kim ◽  
K. Kato ◽  
K. Hokkirigawa ◽  
H. Abe´
Keyword(s):  
Silicon Nitride ◽  
Wear Rate ◽  
Contact Area ◽  
Ceramic Materials ◽  
Rolling Friction ◽  
Bearing Steel ◽  
Rolling Contact ◽  
Hertzian Contact ◽  
Real Contact Area ◽  
Wear Process

Wear tests in dry rolling contact were carried out at room temperature on five ceramic materials, such as silicon nitride, silicon carbide, cermet, titania, and alumina. The results showed that wear rate of silicon nitride was smaller than any of the other ceramic materials and bearing steel. Observations of worn surface and wear debris revealed that ceramic materials have two types of wear, one related to real contact area and another related to Hertzian contact area. It was also found that brittle fracture dominates the wear process of ceramic materials in dry rolling contact. Based on the experimental results, wear rate of ceramic materials was expressed with a new nondimensional parameter.

Bearing Vibration and Oil Film Thickness in Relation to Sphericity of Bearing Steel Balls

1992 ◽  
Author(s):  
F. Itoigawa ◽  
T. Nakamura ◽  
K. Funabashi
Keyword(s):  
Film Thickness ◽  
Three Dimensional ◽  
Large Error ◽  
Bearing Steel ◽  
Rotational Axis ◽  
Ball Bearings ◽  
Elliptical Cross ◽  
Oil Film ◽  
Bearing Vibration ◽  
Steel Balls

Abstract The relationship between the bearing vibration and the sphericity of the steel balls used for ball bearings is experimentally investigated in consideration of the oil film in between the steel balls and raceways. The experiments are carried out on angular contact ball bearings (7208C and 7010C) under only thrust load. First, it is confirmed that the oil film thickness, which is measured on this bearing, virtually agrees with the value calculated by EHL theory. And even if there exists a considerably large error in the ball shape, it does not always necessarily rupture the oil film if it is sufficiently thick. Second, in a simple two-bearing-shaft system, the even-order undulation of form error of ball, especially, second-order undulation, can cause bearing vibration. Furthermore, when the ball has a three-dimensional shape like a rugby ball, with elliptical cross-sections, the ball determines its own rotational axis.

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