STANDARD SLEEVE BEARINGS
Zincaloy ZA12 Series
ZA12 bearings are the cost effective alternative to traditional SAE-660 bronze sleeve bearings
ZA-12 Bearings are stocked in semi-finished state for fast delivery to specific sizes.
Stock sizes range from 0.625″ O.D. throught to 9″ O.D. in 0.125″ increments for small diameters to 0.25″ increments for larger sizes.
As cast hollow stock sizes inclide 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.
ZA12 Properties
ZA12 Comparison
ZA12 Bearings are reliable alternatives to Bronze and Aluminum Bronzes with very low sensitivity to pounding, lack of lubrication and contamination.
Bearing Pressure vs Sliding Speed
ZA12 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.
Bearing Pressure vs Sliding Speed
ZA12 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. ZA12 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-12 Zinc Alloy Bearing Design Notes
Corrosion
ZincaloyTM 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. ZincaloyTM 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 ZincaloyTM bearings. However, under extreme conditions of dry running, ZincaloyTM is superior to bronze under such conditions because a thin film of ZincaloyTM 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 ZincaloyTM. Small diameter bearings under 3 inches (75mm) usually require no grooving. Groove edges should be rounded to prevent lubrication from being scraped from the shaft. Standard greases normally used for bronze bearings are compatible with ZincaloyTM. Acidic, alkaline or sulphur containing lubricants should be avoided to prevent corrosion.
The maximum recommended running temperature for ZincaloyTM bearings is 100oC (212oF).
Standard grease grooves are available, Z1, through Z5. Special groove configurations can be supplied based
on operational requirements.
For sizes greater than 9″ diameter and for technical support please contact Canadian Babbitt Bearings for your engineered bearing solutions at: