scholarly journals The Effect of a Gear Oil on Abrasion, Scuffing, and Pitting of the DLC-Coated 18CrNiMo7-6 Steel

Coatings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 2 ◽  
Author(s):  
Remigiusz Michalczewski ◽  
Marek Kalbarczyk ◽  
Anita Mańkowska-Snopczyńska ◽  
Edyta Osuch-Słomka ◽  
Witold Piekoszewski ◽  
...  
Keyword(s):  
Simple Model ◽  
Mineral Oil ◽  
Hardened Steel ◽  
Crn Coating ◽  
Gear Teeth ◽  
Hard Particles ◽  
Polyalkylene Glycol ◽  
Gear Oil ◽  
Gear Oils ◽  
Harsh Conditions

The transmissions of mining conveyors are exposed to very harsh conditions. These are primarily related to the contamination of the gear oil with hard particles coming from coal and lignite, which can cause intensive abrasive wear, scuffing, and even pitting, limiting the life of gears. One of the ways to prevent this problem is the deposition of a wear-resistant coating onto gear teeth. However, a proper choice of gear oil is an important issue. The abrasion, scuffing, and pitting tests were performed using simple, model specimens. A pin and vee block tester was employed for research on abrasion and scuffing. To test pitting, a modified four-ball pitting tester was used, where the top ball was replaced with a cone. The test pins, vee blocks, and cones were made of 18CrNiMo7-6 case-hardened steel. A new W-DLC/CrN coating was tested. It was deposited on the vee blocks and cones. For lubrication, three commercial industrial gear oils were used: A mineral oil, and two synthetic ones with polyalphaolefin (PAO) or polyalkylene glycol (PAG) bases. The results show that, to minimize the tendency forabrasion, scuffing, and pitting, the (W-DLC/CrN)-8CrNiMo7-6 tribosystems should be lubricated by the PAO gear oil.

scholarly journals Abrasive Wear, Scuffing and Rolling Contact Fatigue of DLC-Coated 18CrNiMo7-6 Steel Lubricated by a Pure and Contaminated Gear Oil

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7086
Author(s):  
Waldemar Tuszyński ◽  
Remigiusz Michalczewski ◽  
Edyta Osuch-Słomka ◽  
Andrzej Snarski-Adamski ◽  
Marek Kalbarczyk ◽  
...  
Keyword(s):  
Abrasive Wear ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Solid Particles ◽  
Rolling Contact ◽  
Lubricating Oil ◽  
Gear Teeth ◽  
Ball Rolling ◽  
Gear Oil ◽  
Gear Oils

Due to extreme working conditions of mining conveyors, which contaminate gear oil with solid particles, their transmissions are exposed to intensive abrasion, scuffing, and even rolling contact fatigue (pitting). These effects shorten gear life. To prevent their occurrence, a wear-resistant coating can be deposited on gear teeth. The resistance to abrasive wear, scuffing, and pitting was investigated and reported in the article. Simple, model specimens were used. Abrasive wear and scuffing were tested using a pin-and-vee-block tribosystem in sliding contact. A cone–three-ball rolling tribosystem was employed to test pitting. The material of the test specimens (pins, vee blocks, cones) was 18CrNiMo7-6 case-hardened steel. Two types of DLC (Diamond-like Coatings) coatings were tested, W-DLC and W-DLC/CrN. The vee blocks and cones were coated. Two industrial gear oils were selected to lubricate the specimens: one with a mineral and one with a synthetic PAO (polyalphaolephine) base, as pure oil or contaminated with solid particles from a coal mine. The results show that, to minimize the tendency to abrasion, scuffing, and pitting of specimens made of 18CrNiMo7-6 steel, the W-DLC/CrN coating should be deposited. This coating also gives very good protection when the lubricating oil is contaminated.

Formulation of a Biobased Gear Oil Utilizing Boron Technology

2012 ◽  
Author(s):  
Kenneth M. Doll ◽  
Glenn L. Heise ◽  
Malgorzata Myslinska ◽  
Brajendra K. Sharma
Keyword(s):  
Soybean Oil ◽  
Ring Opening ◽  
Effective Properties ◽  
Wear Test ◽  
Triacylglycerol Structure ◽  
Heat Treated ◽  
Natural Oil ◽  
Gear Oil ◽  
Gear Oils ◽  
Biobased Content

A new additive was produced from a natural oil and boron. The synthesis involves the use of the epoxidized form of soybean oil which then undergoes a catalytic ring opening to produce the additive material. Due to their remaining triacylglycerol structure, the products are highly compatible with bio-based lubricants and due to their covalent boron attachments, show effective properties for the reduction of wear. Some performance examples: Using a traditional Falex 4-ball wear test, the scar diameter observed in a soybean oil lubricant could be reduced from 0.61 mm to 0.41 mm by the inclusion of 1% or the additive. A second generation additive, while not as effective at reducing wear, was able to increase the oxidation onset temperature of soybean oil under pressurized oxygen by 14 °C. Next, these additives were tested in a formulation of biobased gear oil composed of heat treated soybean oil and synthetic esters. In the best formulation, these additives were able to surpass the oxidation onset of a gear oil that was formulated with commercially available additives, while giving nearly as good of performance by wear scar analysis. This oxidation onset value, of 258 °C, approaches that of off-the-shelf gear oils. Overall, these new additives are strong performers which can be made using simple chemistry. Their properties combined with their high biobased content are valuable assets in the search for biobased lubricants and gear oils.

Continuous as Against Intermittent Fling-Off Cooling of Gear Teeth

1974 ◽  
Vol 96 (4) ◽  
pp. 529-538 ◽  
Author(s):  
G. J. J. van Heijningen ◽  
H. Blok
Keyword(s):  
Experimental Data ◽  
Continuous Method ◽  
Main Subject ◽  
Gear Teeth ◽  
Naturally Occurring ◽  
Cooling Method ◽  
Oil Mist ◽  
Gear Oil ◽  
Design Calculations

The main subject of the present paper is the still relatively unknown fling-off cooling method through continuous supply of the gear oil to the roots of the tooth faces to be cooled, for instance through holes connecting with a manifold inside the tooth rim. The cooling potentialities of this continuous method are compared with those of the naturally occurring “intermittent” fling-off cooling treated previously by A. de Winter and H. Blok [1]. A third fling-off cooling method is again continuous but, in contrast to that by root supply, occurs naturally in that it is brought about by the impingement of comparatively cool droplets from the oil mist in the gear casing. This method will be treated only cursorily, lacking certain experimental data to be substituted in design calculations based on the pertinent theoretical relationships.

Gear oil influences on efficiency of gear and fuel economy of cars

2000 ◽  
Vol 214 (2) ◽  
pp. 189-196 ◽  
Author(s):  
W. J. Bartz
Keyword(s):  
Fuel Consumption ◽  
Fuel Economy ◽  
High Efficiency ◽  
Friction Reduction ◽  
Friction Modifiers ◽  
Oil Viscosity ◽  
Fuel Economy Improvement ◽  
Viscosity Grade ◽  
Gear Oil ◽  
Gear Oils

1. First of all, it should be considered that the fuel consumption of a car depends on a set of parameters only partly related to tribology. Their influence is much more pronounced than that of the lubricant. 2. Only the mechanical losses can be decreased by lubricant-related measures. Therefore, the fuel economy improvement that possibly might be realized is rather limited, especially when taking into account the rather high efficiency of gears. 3. When evaluating the influence of viscosity on fuel consumption, the so-called effective viscosity must be taken into account. This is most important for non-Newtonian oils. 4. Reducing the gear oil viscosity by one SAE viscosity grade will result in fuel consumption reductions of 0.2-1.5 per cent at high temperatures and 0.4-2.5 per cent at low temperatures. 5. Using friction modifiers in gear oils, fuel consumption reductions of between 1.0 and 6.0 per cent are realistic. 6. On the basis of a 50 per cent friction reduction maximum fuel consumption reductions between 1.0 and 5.1 per cent by other gear oils are possible, considering different driving programmes. 7. Tests with a real automobile gear resulted in fuel economy improvements of the order of magnitudes of 1 per cent by other gear oils. 8. The results of measurements confirm in principle the calculated estimations.

A Theoretical Discussion of Pitting Failures in Gears

1948 ◽  
Vol 158 (1) ◽  
pp. 317-326 ◽  
Author(s):  
R. Beeching ◽  
W. Nicholls
Keyword(s):  
General Solution ◽  
Theoretical Consideration ◽  
Hardened Steel ◽  
Contact Stresses ◽  
Theoretical Discussion ◽  
Principal Stresses ◽  
Core Strength ◽  
Line Load ◽  
Gear Teeth ◽  
Surface Failure

This paper is primarily concerned with the theoretical consideration of the stresses that cause surface failure of gear teeth. Methods of calculating the permissible line load between contacting cylindrical surfaces for static or cyclic conditions are considered, and the probable effects of friction are discussed qualitatively. Maximum permissible case thicknesses are suggested for case-hardened steel components of varying core strength when subjected to contact stresses of the type encountered in gears, rollers, and cams. In the Appendix is given an account of the derivation (from Hertz's general solution) of expressions for the principal stresses at any point in the neighbourhood of the zone of contact between parallel cylinders. These expressions, which lend themselves to ready computation, reduce to the same form as those derived by Thomas and Hoersch for stresses in the plane of symmetry, but they are more widely applicable.

Fling-Off Cooling of Gear Teeth

1974 ◽  
Vol 96 (1) ◽  
pp. 60-70 ◽  
Author(s):  
A. DeWinter ◽  
H. Blok
Keyword(s):  
Frictional Heat ◽  
Heavy Duty ◽  
Gear Teeth ◽  
Gear Oil

An exploratory theory shows even moderate rates of supply of the gear oil to the tooth faces to suffice for attaining the limiting coolant capacity that proves to be inherent in the conventional centrifugal fling-off process. However, in heavy-duty gears beyond a certain size and speed the conventional “intermittent” fling-off cooling can no longer take a substantial share in the withdrawal of the frictional heat generated in the meshing zone. Much greater cooling capacities are then realizable by the less known “continuous” fling-off process, to be dealt with in a followup paper.

The Scuffing Resistance of WC/C Coated Spiral Bevel Gears

2014 ◽  
Vol 604 ◽  
pp. 36-40 ◽  
Author(s):  
Remigiusz Michalczewski ◽  
Marek Kalbarczyk ◽  
Waldemar Tuszynski ◽  
Marian Szczerek
Keyword(s):  
Bevel Gear ◽  
Spiral Bevel Gear ◽  
Test Rig ◽  
Low Friction ◽  
Spiral Bevel Gears ◽  
Gear Teeth ◽  
Bevel Gears ◽  
Trade Name ◽  
Gear Oil ◽  
Spiral Bevel

One of the main problems with the operation of spiral bevel gears is related to very severe conditions in the contact of the meshing teeth; therefore, lubrication is very difficult, which increases the risk of scuffing occurrence. One of the ways to achieve better scuffing resistance is by the deposition of a low-friction coating on the bevel gears teeth. Gear scuffing tests were performed using a bevel gear test rig designed and manufactured at ITeE-PIB. The authorial bevel gear scuffing test was performed. Specially designed, spiral bevel gears were used for testing. Two material combinations were tested: uncoated pinion - coated wheel and, for reference, both gears without coatings. The a-C:H:W (trade name WC/C) coating of DLC type was deposited on the wheel teeth. A mineral, automotive gear oil of API GL-5 performance level was used for lubrication. It is shown that the resistance to scuffing may be significantly improved when the a-C:H:W coating is deposited on the spiral bevel gear teeth.

scholarly journals Influence of Contamination of Gear Oils in Relation to Time of Operation on Their Lubricity

2021 ◽  
Vol 11 (24) ◽  
pp. 11835
Author(s):  
Leszek Gil ◽  
Krzysztof Przystupa ◽  
Daniel Pieniak ◽  
Edward Kozłowski ◽  
Katarzyna Antosz ◽  
...  
Keyword(s):  
Solid Particles ◽  
Friction Reduction ◽  
Test Results ◽  
Oil Viscosity ◽  
Heavy Trucks ◽  
History Of ◽  
Gear Oil ◽  
Wear Products ◽  
Gear Oils ◽  
Time Of Operation

The quality and reliability of consumables, including gear oils, results in the failure-free operation of the transmission components in heavy trucks. It is known that oil viscosity is essential for all lubricated tribopairs for wear and friction reduction in all vehicles with a gearbox. Viscosity may be influenced by the contamination that wear products can impart on the oil. Oil contamination can also affect lubrication efficiency in the boundary friction conditions in gearboxes where slips occur (including bevel and hypoid gearboxes). The present research focused on this issue. An obvious hypothesis was adopted, where it was theorized that exploiting the contaminants that are present in gear oil may affect how the lubricating properties of gear oils deteriorate. Laboratory tests were performed on contaminants that are commonly found in gear oil using the Parker Laser CM20. The study was designed to identify a number of different solid particles that are present in oil. At the second stage, friction tests were conducted for a friction couple “ball-on-disc” in an oil bath at 90 °C on a CSM microtribometer. The quantitative contamination of the gear oils that contained solid particles and the curves representing the friction coefficients of fresh oils with a history of exploitation were compared. The test results were statistically analysed. Exploitation was shown to have a significant impact on the contamination of gear oils. It was revealed that the contamination and the mileage had no effect on the tested oils.

Power Loss in FZG gears lubricated with industrial gear oils: Biodegradable Ester vs. Mineral oil

2005 ◽  
pp. 421-430 ◽  
Author(s):  
R. Martins ◽  
J. Seabra ◽  
Ch. Seyfert ◽  
R. Luther ◽  
A. Igartua ◽  
...  
Keyword(s):  
Power Loss ◽  
Mineral Oil ◽  
Gear Oils

Water Soluble, Environmentally Acceptable Lubricants in Stern Tube Applications

2015 ◽  
Author(s):  
John V. Sherman
Keyword(s):  
Mineral Oil ◽  
Water Soluble ◽  
Normal Operation ◽  
Unique Combination ◽  
Tube System ◽  
Environmental Properties ◽  
Polyalkylene Glycol ◽  
Tube Application ◽  
The U.S ◽  
Specific Amount

Stern tube lubricants; used to lubricate the bearings that support the vessel propeller shaft in the stern tube, are continuously lost to the marine environment while the ship is moving under power. Although the specific amount of lubricant lost in a stern tube application is dependent on the particular stern tube system and vessel type, many reports support the fact that lubricant loss through vessel stern tubes is by far the greatest source of lubricant ingression into the environment of all vessel lubricant applications incidental to their operation. Historically, stern tube lubricants have been based on mineral oil but recently synthetic, environmentally acceptable stern tube lubricants have been made available. The U.S. EPA Vessel General Permit for Discharges Incidental to the Normal Operation of Vessels (VGP) revised in 2013, mandated the use of environmentally acceptable lubricants (EALs) for all oil-to-sea interface applications in vessels constructed on or after December 19, 2013 and all vessels built before December 19, 2013 unless technically infeasible. The VGP specifically defines stern tube lubrication as an oil-to-sea interface application. One type of EAL recommended by the U.S. EPA to replace mineral oil in all oil-to-sea interface applications is based on polyalkylene glycol (PAG) base stocks. PAG based lubricants offer a unique combination of performance and environmental properties.

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