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Metal bearings suffer from the elements and in corrosive environments. PolyLube composite bearings feature resin and fibers that are both highly corrosion resistant and reduce the need for seals. Additionally, PolyLube composite bearings never need greasing, making your equipment maintenance free.

  • Being permanently greaseless due to a PTFE bearing liner, there is no need to worry about water contamination in a lubricant.
  • PolyLube is not prone to expansion like thermoplastic bearings are in submerged applications.
  • PolyLube composite bearings use engineered resins reinforced with high strength continuous fibers for a product with higher load capacities than bronze bushings and a much longer wear life than metal-backed bearings.

Many highly corrosive environments are prime candidates for Polylube:

  • Agricultural equipment with exposure to Ammonium Nitrate
  • Material handling equipment exposed road salt and sand
  • Water and oil pumping, especially when submerged
  • Marine applications where salt exposure occurs

Technical Considerations

Pin corrosion will affect the surface finish of the pin as well as the running clearance. As a pin corrodes, there are a number of consequences to the operation of the joint. The three main problems introduced into the joint are increased pin OD, rougher surface finish, and oxide material contamination. The increased pin diameter could result in an interference fit and increased torque needed to turn the pin. The increased roughness of the pin surface will serve to additionally increase the torque required to operate the joint as well as increase the rate of wear. The addition of contaminates, in the form of the metal oxide, will further degrade the pin and bearing. Protecting the pin and bearing from contamination will lead to long term predictable wear regardless of the frequency of operation of the equipment.

Polygon recommends a corrosion resistant surface treatment for pins used in dry running applications. Many years of success have been experienced with customers using Hard Chrome, Electroless Nickel, and Nitrocarborization. Pins with these surface treatments will have hardness in excess of the Polygon recommendations for moderate to highly contaminated environments. Thickness or depth of the treatment should be determined based on the chosen materials. Typical values are 0.0005 inches for both thickness and white layer depths. These values are not intended as recommendations, only as examples to allow designers a value to begin a conversation with pin suppliers.

Softer surface treatments are also in use with Polygon bearings. Yellow Zinc Dichromate (YZD) is a cost effective alternative to the previous treatments given. YZD can be thought of as metal paint. The coating will be removed in the contact area by the bearing very quickly. The break-in period between the bearing and the base material will begin after the YZD has been worn away. There will be some added wear resulting from worn away YZD acting as contamination. Equipment seasonal in nature will also have a possibility of pin corrosion at the contact area. The transferred PTFE will act as a corrosion inhibitor if a sufficient amount has been transferred during the first season operation. The main purpose most designers state when using YZD is corrosion protection for the surface not in contact with the bearing. The result is a decrease in the migration of metal oxide particles into the joint compared to an untreated pin.


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Disclaimer

Any ratings are typical for design purposes. Your design parameters may affect final ratings. Consult with a Polygon sales engineer for guidance. Final testing and approval is the customer's responsibility for their application. This information is derived from our testing and published data. There is no assurance of these properties, or warranty provided that these products are suitable for any particular purpose or operational situation.

Polygon certifies that their product will be free from material defect. Polygon will not accept any liability for loss, damages, or costs from use or misuse of our products.

Specifications are subject to change, and may be affected by our continual process of improvement. Changes may be made without prior announcement.

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