Standard Sleeve Bearings

Zincaloy™ ZA12 Series Sleeve Bearings

ZA12 bearing are the cost-effective alternative to traditional SAE-660 bronze sleeve bearing.

• RESILIENCE – Protects housings from deformation due to pounding.
• BETTER DRY RUNNING PROPERTIES – Resists damage to shaft if lubrication fails.
• LOW COEFFICIENT OF FRICTION
• BETTER MECHANICAL PROPERTIES – Especially strength, toughness and hardness.
• BETTER DAMPENING PROPERTIES – Absorbs impact energy well to reduce vibration.
• HIGHER TOLERANCE OF FOREIGN SUBSTANCES – Ability to absorb foreign particles to avoid shaft damage.
• LIGHTER WEIGHT – 32% Lighter.
• FREE MACHINING – Excellent surface finish.
• LONGER BEARING LIFE
• LEAD-FREE

ZA-12 Bearings are stocked in semi-finished state for fast delivery to specific sizes.

Stock sizes range from 0.625″ O.D. through to 9″ O.D. in 0.125″ increments for small diameters to 0.25″ increments for larger sizes.

As cast hollow stock sizes include a 1/8 inch machining allowance on the I.D. and O.D. i.e. a 5 x 6 inch hollow is actually 4-7/8 inches x 6-1/8 inches, which is designed to finish to 5 x 6 inches. The ZA-12 hollow sizes are listed in finished sizes.

ZA-12 Properties

ZA-12 Comparison

Bearing Pressure vs Sliding Speed

ZA-12 bearings can be substituted for SAE-660 bronze bearings in most cases without any design changes.

Guidelines only differ in relation to press fits and clearances at elevated temperatures.

ZA-12 stock is suitable for bearing use under the following operating conditions: Maximum pressure on the bearing at a low shaft rotation speed (less than 10 ft/min surface speed) should be kept between 4500 and 6000 psi. As shaft speed increases to 60 ft/min and beyond, the recommended operating pressure decreases to about a 1000 psi.

ZA-12 bearings can operate well at very high speeds under low loads as long as the heat generated does not exceed 100ºC (212ºF) and the bearings are well lubricated.

ZA – 1 2 Bearing Design Notes

Corrosion

Zincaloy™ bearings offer good resistance to atmospheric corrosion as well as a variety of plant environments. However, direct exposure to corrosive liquids and gases should be avoided. Contact liquids should have a pH of 6-11.5 to avoid corrosion problems. Zincaloy™ may experience bimetallic galvanic corrosion if in contact with other metals, however, under atmospheric conditions this is generally small and of no concern.

It can be of concern in a constantly wet environment or in sea water. Under these circumstances the material should be tested to determine its suitability

Dry Running

Most bearings perform best if lubricated, including Zincaloy™ bearings. However, under extreme conditions of dry running, Zincaloy™ is superior to bronze under such conditions because a thin film of Zincaloy™ is smeared over the shaft which protect it from wear and damage/

Zinc alloy metals generally do not spark when struck by rusted ferrous materials

Sleeve Bearing Lubrication

Standard grease groove designs for bronze bearings are suitable for Zincaloy™​. A small diameter bearing under 3 inches (75mm) usually requires no grooving. Groove edges should be rounded to prevent lubrication from being scraped from the shaft. Standard greases normally used for bronze are compatible with Zincaloy™. Acidic, alkaline or sulphur containing lubricants should be avoided to prevent corrosion.

The maximum recommended running temperature for a Zincaloy™ bearing is 100ºC (212ºF)

Grease grooves are available standard, Z1, through Z5.

Special groove configurations can be supplied based on operational requirements.

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