White Metal Bearings
INTRODUCTION
White Metal or Babbitt Metal is a soft white, anti-friction alloy originally developed by Issac Babbitt in 1839 which mainly consisted of Tin, Copper and Antimony. Fast forward to today, and you will find quite a variety of white silvery alloys with varying characteristics.
DESCRIPTION
White metal is primarily used to line cast iron, steel and bronze bearing shells. White metal can be either a tin based or lead based alloy containing moderate amounts of copper and antimony. Tin based white metals are used for high load and high operating temperature applications. Tin based white metals have excellent corrosion resistance, high interface bond strength and a low tendency for separation of metallic phases and fusion to mating parts. Lead based white metals are inexpensive, but are limited to use in moderate load and moderate operating temperature applications, as they have less desirable chemical and mechanical properties.
APPLICATIONS
Mills | Pumps | Diesel Motors |
Compressors | Refrigeration | Turbines |
Electric Generators | Automotive | Gearboxes |
Electric Motors | Fans | Crushers |
COMMON WHITE METAL GRADES
ASTM B23 No. 2
The most commonly used tin based white metal which can be used for a large range of applications. Almost identical to Hoyts 11R, with the only difference being a lower cadmium content.
Sn | Sb | Cu | Pb | Fe | As | Bi | Zn | Al | Cd |
88 – 90 | 7 – 8 | 3 – 4 | 0.35 | 0.08 | 0.10 | 0.08 | 0.005 | 0.005 | 0.05 |
WM 11 / Mill F
The most commonly used lead based white metal which is normally used for large bearing surfaces subjected to moderate loads and temperatures.
Sn | Sb | Cu | Pb | Fe | As | Bi | Zn | Al | Cd |
7 – 8 | 15 – 16 | 0.7 | 74 – 76 | 0.01 | 0.50 | 0.02 | 0.001 | 0.001 | 0.50 |
Client Specified Composition
At Harfords we are able to determine the exact composition of the existing white metal on a component. We can then recommend a suitable, readily available alternative, or produce a custom batch of white metal to suit the client’s requirements.