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What is babbitt metal

What is babbitt metal?

Babbitt metal is a tin based and lead based bearing alloy with antifriction properties, which was invented by Babbitt. Because of its white, also known as white alloy. The main composition of babbitt alloy is tin, lead, antimony and copper. Antimony and copper are used to improve the strength and hardness of the alloy.

Babbitt is used to make plain bearings.
There is strong friction between sliding bearing and high-speed and heavy-duty shaft, so the microstructure of sliding bearing alloy is required to have two kinds: hard point on soft matrix and soft point on hard matrix. Soft base can bear impact and vibration, good running in; hard point can reduce the contact surface with the shaft, reduce the friction coefficient, reduce wear, good wear resistance. The concave convex gap between the soft substrate and the hard point is also conducive to the storage of lubricating oil.

Babbitt alloy belongs to hard point structure with soft matrix. Copper based and aluminum based bearing alloys are commonly used in hard matrix and soft texture.

Types of babbitt alloys

Babbitt alloys can be divided into tin based and lead based:

Tin-base babbitt metal 

Tin based babbitt alloy is based on tin, adding a small amount of antimony and copper. The soft matrix of tin based bearing alloy is the solid solution of antimony in tin, and the hard point is the metal compound SnSb, cu3sn, etc. The code of tin based bearing alloy is composed of ZcH (the first and last Chinese pinyin of “cast bearing”), chemical symbols of basic elements, chemical symbols of main additive elements and average percentage value of main additive elements. For example, zchsnsb11-6 is a tin based cast bearing alloy with antimony content of 11% and copper content of 6%.

Tin based Babbitt alloy has good plasticity and thermal conductivity, low friction coefficient and expansion coefficient, but low fatigue strength and low allowable working temperature. It is mainly used for casting bearing bush of large machine, such as high-power high-speed steam engine, main shaft bearing of steam turbine and high-speed large machine tool.

Common tin based Babbitt alloys

Tin base bearing alloy No.1


Tin base bearing alloy No.2


Tin base bearing alloy No.3


Tin base bearing alloy No.4


Lead base babbitt alloy

Lead base babbitt alloy is a bearing alloy based on lead with tin, antimony, copper and other alloying elements added. The soft substrate of lead-based bearing alloy is a solid solution with antimony in lead, and the hard point is metal compounds SnSb, Cu3Sn, etc. The code name of lead-based bearing alloy is similar to that of tin-based bearing alloy and consists of ZCH, base element symbol, main addition element symbol and element content number. For example, ZCHPBSB16-16-2 represents a lead-based bearing alloy with main element antimony WSB =16%, auxiliary element Sn WSN =16% and copper WCu =2%.
Lead base babbitt alloy performance is not as good as tin base babbitt alloy, friction coefficient is larger, impact resistance is not high, but the price is low, so it is generally used in the working temperature is not more than 120℃, medium speed and medium load without obvious impact load, such as motor, crusher, compressor and vacuum pump bearings. There are five kinds of commonly used lead-based bearing alloys, No.1 ~ No.5.
Whether tin base or lead base babbitt alloy, strength is relatively low, can not withstand large pressure, so it is often cast in the steel bearing bush (08 steel) by centrifugal casting method, forming a thin and uniform lining (<0.1mm).

Source: China Metal Flanges Manufacturer – Yaang Pipe Industry (

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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