Three different types of abrasive particles were tested and compared. It was found that types of abrasive particles do not significantly affect the SR as all of them produced an average SR of 8–10nm on the ground sample. It was further observed that a stable oxide layer was formed on the ELID ground sample as anticipated by the researchers that enhances the surface characteristics of the ground sample. In addition, it was found very interestingly that the wettability of the processed surface varies with different method and wheel grit materials. Therefore, researchers proposed that by varying the processing conditions and grinding wheel one can possibly control the surface behavior including hydrophilicity of the surfaces. is a high carbon, chromium containing low alloy through hardening steel. This steel has high hardness , high wear resistance , and rolling fatigue strength, which makes it specially adapted for roll bearings.
This alloy provides a significant lower cost way to fight wear and galling compared to Nickel or Cobalt based alloys. The corrosion resistance of Armco NITRONIC 60 Stainless Steel falls between that of types 304 and 316. However, experience shows that in a wear system, a galling or siezure failure occurs first, followed by dimensional loss due to wear, and finally corrosion. Galling and wear must be the first concerns of the design engineer. Corrosion tests are not normally performed with NITRONIC 60 High Strength. To determine if the bearing condition was stable or deteriorating, lube oil contamination parameters were monitored and tracked regularly, as shown in Figure 12. This allowed the unit to operate until after the severe weather had passed. The failure occurred during an operating period with record cold temperatures. The unit needed to be available for full-load operation and had to run regardless of the suspected bearing condition.
When properly designed, they can be both economical and highly functional. Their manufacturing method consists of briquetting the metal powder mixtures to the proper density. Subsequently, they are sintered for different duration subject to the temperatures. Sintered bearings are then sized to obtain the required dimensional characteristics. This is followed by inspection and impregnation with a lubricating oil. Proper running clearance for bearings depends to a great extent on the particular item. Only minimum recommended clearances for oil impregnated bearing used with ground steel shafting are listed. As in all bearings, satisfactory operation of porous-metal bearings require suitable clearances between shaft and housing. While guidelines depend on the materials used and the nature of the application, a representative chart showing recommended bearing clearances for porous-bronze and porous-iron bearings is given in Figure 1. Most engineering data relating to the PV factor lists an upper limit, of the factor, i.e. a value which should not be exceeded for satisfactory bearing operation.
Compositions vary, but most modern bronze is 88% copper and 12% tin. Bronze may also contain manganese, aluminum, nickel, phosphorus, silicon, arsenic, or zinc. Stainless steel is the ideal material for machinery in the Food/Beverage/Pharma industries because it has the corrosion resistance to tolerate frequent water washowns, sanitizing agents, acid/alkali exposures. It also offers the rust-resistance to avoid contamination of the product. However, most bearings in stainless steel machinery are made of carbon steel due to mechanical ductility. These carbon steel bearings corrode much more easily than the equipment itself, especially under the constant cleaning/water exposure. If your rebuilder can’t tell you what grade and composition of babbitt he is using, or what temperature he is pouring at, it is time to find another rebuilder! The same is true if you find out he is using lead-based babbitt rather than tin-based babbitt for crankshaft main and connecting rod bearings. Actually both lead and tin based white metal bearing alloys were commonly and commercially known as ‘Babbitt’, and that is a fact that exists to this day, as seen in the current ASTM specification which covers all grades of both classes. Porous-metal bearings are used widely in instruments and general machinery, in which their self-lubricating characteristics and load-carrying ability is very desirable.
Three different types of abrasive particles were used for comparison. All three abrasives produced a similar surface roughness of 8–10 nm. Also, ELID ground surface was compared with normal polished surface (P-series). Further, the observation suggests that the ELID mirror surface grinding process produced a stable oxide layer on the workpiece surface, and also that the abrasive elements of the grinding wheel penetrated and diffused into the workpiece. In addition, it was found very interesting that the wettability of the processed surface varies with different methods and wheel grit materials. Therefore, authors proposed that by varying the processing conditions and grinding wheel, one can possibly control the surface potential characteristics and even hydrophilicity of the surfaces.
We offer reliable partnerships based on trust, compassion, determination, collaboration and respect. GGB tribological solutions move the industrial world one step closer to the future. Our products are used in tens of thousands of critical applications every day—around the planet. Our goal is to provide reliable, maintenance-free surface solutions for almost any application—no matter where those demands take our products. SBE 70 composite is a coarse weave cotton fabric impregnated with a modified phenolic/alumina resin formulation made in a red color for easier inspection of bearing surfaces. Composite bearings achieve their finished dimensions using traditional machining systems. This gives the designer a high degree of flexibility to produce a finished part which is perfectly aligned to the application in question. Together with you, we translate technical challenges into tailor-made solutions. Extensive material knowledge is linked to a broad experience in specific applications. A competitively priced offer and high-quality components and assemblies.
The PTFE surfaces of the bearings shall be maintained clean and free from grit, dirt or grease. The sliding surfaces shall be a nominal 3/32” glass-filled virgin PTFE factory-bonded with a tested epoxy to a steel back-up plate. The bonding shall be done in a heated bonding press under a controlled time, temperature and pressure. The coefficient of friction shall average .06 under a compressive load of 2000 psi. The compressive creep shall be a maximum of 2% at 2000 psi and 70° F. Our engineers can provide guidance in selecting the right type of steel balls for your application, including size, materials, and quantities.
The grease composition described in the above-mentioned or , designed for rolling bearings. There is proposed a lubricant comprising as the antistatic agents an ionic liquid and a lithium compound (JP A). Generally, the grease composition uses as the base oil mineral oils such as paraffinic oils and naphthenic oils or synthetic oils such as ester-based synthetic oils, synthetic hydrocarbon oils, ether-based synthetic oils and the like. Those base oils themselves show considerably high volume resistivities. Therefore, it is known that the bearing or mechanical part filled with a grease composition containing any of the above-mentioned base oils becomes an insulator, thereby being electrically charged by the actions of rotation or sliding. The present invention relates to a grease composition and a mechanical part.
British Admiralty gunmetal, with its nominal composition 88% copper, 10% tin, and, 2% zinc, was thus developed. Similar specifications also became standard, the French ordnance alloy being Cu-90%, Sn-6% Zn-4%, and the U.S. Ordnance alloy Cu-88%, Sn-8% Zn-4%, this latter specification being now covered by G2-C. Mobil Infinitec 152 far exceeds the requirements of the ASTM D 4950 GC-LB grease classification for automotive wheel bearing and chassis applications. Mobil Infinitec 152 was specifically designed to meet the demand for better durability and enhanced high-temperature lubrication in four-wheel drive truck and sport utility vehicle wheel bearings. After extensive testing, a major bearing manufacturer has approved Mobil Infinitec 152 for factory fill in their new high-performance automotive wheel bearings. Mobil Infinitec 152 super-long-life grease, recommended for a wide range of automotive and industrial applications, represents a major advance in lithium-complex grease technology. Developed and patented by ExxonMobil Research and Engineering, the proprietary technology of Mobil Infinitec 152 has set a new standard for lithium-complex grease high-temperature performance.
I happened on some large roller bearings and am trying to figure out their composition. These tools got a workout during WWII in the US Steel machine shop fitting bearings to shafts. My father ran the horizontal press that put bronze bearings on ship shafts and if there were no shafts in the shop they worked on bearings. The majority of the Liberty ship shafts came through this shop. It consists of two metallic rings known as inner ring and outer ring. The inner ring is mounted on the shaft with its lower surface and the outer surface of it has the groove made centrally all over the circumference known as inner race.
A small amount of effort is required to force the bearing inset into place during assembly. Grooved bearings should never be used on the lower half of the bearing shell. Again, maintaining the load-carrying capacity of the hydrodynamic wedge via proper clearances and oil pressure is the primary goal. Rod bearings are not grooved because they are fully loaded all the way around. Where available, full property information can be viewed for materials including chemical composition, mechanical properties, physical properties, advanced property data and much more. G3 alloy, particularly in the sand-cast condition “as cast”, shows improved tensile strength, elongation, compressive strength, hardness and impact resistance compared with Admiralty Gunmetal G1. However, its production is slightly more difficult and calls for special care of techniques of manufacture. These mechanical properties can be improved still further by heat treatment but at the expense of some impact resistance and ductility. TECAPEEK® PVX is an ultra high performance bearing material with wear enhancing additives.
Examples of the second type of bearing are Oilites and plastic bearings made from polyacetal; examples of the third type are metalized graphite bearings and PTFE bearings. [psi sfm (MPa m/s)]Graphalloy−450–750 °F or −268–399 °C750 psi or 5 MPa75 (0.38 m/s)12,000 (0.42 MPa m/s)Graphite???? Unalloyed graphite bearings are used in special applications, such as locations that are submerged in water. Integral bearings are not as common because bushings are easier to accommodate and can be replaced if necessary. Depending on the material, an integral bearing may be less expensive but it cannot be replaced. If an integral bearing wears out, the item may be replaced or reworked to accept a bushing.
There are many sizes and gauges used in a variety of applications. The composition of claim 1 wherein the overbased calcium sulfonate grease further comprises from about 30 weight percent to about 80 weight percent solvent neutral oil. The amount of colorant required in the compositions of the invention is desirably a minor amount that is effective to produce a readily identifiable color in the resultant bearing cleaning composition. Water functions very similarly as hexylene glycol, which is to provide a polar environment to facilitate the conversion of the original Newtonian fluid to a grease-like composition. A particularly preferred range of water content is from about 4 weight percent to 5 weight percent, by weight of the combined reactant. Where the amount of water approaches the low end of the stated range, or about 1 weight percent, the phase transition will be slow or even incomplete. After stirring the resultant mixture for at least 10 minutes, the alkylbenzene sulfonic acid is added, followed by another 20 minutes of stirring.