What is babbitt? Manufacturer, price, brand + Photo and Video

Babbit is a created alloy of metals in artificial conditions, which has different chemical properties. The alloy is based on metals that are similar to each other by a low melting point.

These metals include tin, antimony, lead and arsenic.

Since these components differ slightly in density (some are softer, others are harder), an interesting alloy is obtained with a specific composition and properties that allow to reduce the coefficient of friction (antifriction properties), differ in durability and wear resistance.

What is babbitt?

The invention of this type of alloy was not purposeful, and is the result of a scientific curiosity, when the product of the inventor's activity turned out to be far from the treated result.

The invention of alloys, which are used in many movements, belongs to Isaac Babbitt, who was a professional goldsmith.

He patented his invention back in 1841 and even received a prize for this from the US Congress, which at that time was simply unimaginable - $ 20,000. Six years later, he appeared in Russia.

Classification

To date, the following brands have been worked out and well studied:

• Lead.
• Pewter.

• Calcium.

They are produced in accordance with GOST. For example, calcium babbits must be made according to GOST 1209-90, and lead and tin ones according to GOST 1320-74.

Each of the brands has a certain classification, which is marked with capital letters and numbers:

• Tin babbits have markings B83, B88, B83S, SAE11, ASTM2, SAE12.
• Lead babbits have markings B16, BS6, BN, SAE13, ASTM7, SAE14.

• Calcium babbits have markings BKA, BK2 and BK2Sh.

Main characteristics of babbits and composition

The properties of the above-mentioned brands are evaluated based on the following characteristics:

1. The composition of the alloy and the chemical elements that are included in it.
2. Physical characteristics of an alloy.
3. Foundry and technological characteristics.
4. Mechanical properties.

5. Operating modes and maximum permissible operating limits.
6. Area of ​​use of the alloy.

In terms of chemical composition, alloys differ in what metal is taken as the basis. For example, tin babbit B83 contains up to 85% tin, 12% antimony, and a little copper in the remainder. Lead babbit B16 contains 87% lead and almost everything else is antimony.

The main metal in calcium alloys is lead and can reach up to 96%, and calcium is often added to it.

Reference: To give babbits the required properties, solid elements are added to their composition. These include almost all the elements of rare earth metals such as tellurium, cadmium, antimony, etc.

In terms of physical characteristics, the most interesting are density, specific gravity and resistance to current.For alloys, these indicators are not particularly different from each other, since they are very close.

Of the casting and technological characteristics, the temperature at which the alloy is poured into the bearing and the melting point are of great importance. It varies depending on the chemical additives. For example, the melting point of B83 tin babbit is 365 degrees, and when pouring, the temperature should not be lower than 440 degrees. Alloy grade B16 when melted is 405 degrees, and when pouring it is not less than 480 degrees. Such examples are illustrative and show that when pouring the alloy temperature must always be higher.

At the moment, on an industrial scale, babbits are produced from ore of base metals, or from secondary raw materials that have been sent for processing. For technological expediency, babbits are produced in the form of an ingot. Each ingot weighs 22 kg. In order to combat clandestine production and to organize accounting systems, each ingot is stamped with the manufacturer's trademark. The serial number of the heat according to the factory accounting is also indicated there.

The ingots are then used to pour them into the bearings.

Among the mechanical properties, it is worth highlighting the tensile strength of the casting under short-term load, permissible dimensions, impact strength, hardness and elongation.

Attention! Evaluation of permissible operating modes is carried out according to the following characteristics: part rotation speed, permissible load, permissible heating temperature of the part, shaft rotation hardness.

The scope of one or another type of babbit is determined by such characteristics as specific pressure, work intensity, type of load and maximum operating temperature.

Scope

Depending on the properties that are individual for each type of babbitt, any variety is used strictly as intended.

The purpose can be for mechanisms or for machines, but in general they are used to fill the side walls of the shaft where the bearing is attached. This will help to reduce the coefficient of friction and will inhibit normal rotation.

Due to the low melting point, it is possible to create an excellent effect when gradually grinding rotating parts. This reduces wear on the elements and increases their service life. In addition, when rotating, microchannels appear in the babbit.

All rotating parts are lubricated through them.

Each brand of babbitt has its own area of ​​application. In tin, this is an increase in the wear resistance of parts at high rotation speeds. Those grades that help to provide viscosity, the required temperature indicators and a low coefficient of friction are in great demand.

"Excellent corrosion resistance makes it possible to use babbits even in water and simply in high humidity conditions"

For example, the above example of Babbit B83 is used in bearings that work at high speed and increased dynamic loads.

Real examples of such devices are diesel high-orbit engines, the lower parts of the crackhead bearings of diesel engines with low rpm. In addition, they are used in frame and butterfly bearings, as well as in those that support the propeller shaft on a ship.

In overheating conditions, lead babbits are best. They are used in diesel engines of cars, excavators and tractors. B16 babbit is used for bearings, which are placed in electric locomotive engines.

They are installed on track machines, as well as on equipment that is needed for heavy engineering.

Calcium babbits are used for railway transport, as well as diesel locomotives, passenger and freight cars.

Advantages and disadvantages of alloys

All the alloys described above have their advantages and disadvantages. Of the advantages, we single out:

• Antifriction properties at a high level (they can resist the reciprocating movements of mechanisms).
• High level of anti-corrosion resistance.

• Wear resistance.
• Increased toughness.
• Low melting point (varies from 240 to 340 degrees).
• Increased softening factor of the alloy (at +100 degrees it corresponds to the normalization of HB 9-24).
• Increased impact toughness.

• It takes a little time to run in parts.

There are fewer disadvantages, but they are still there:

• Low strength (in comparison with other alloys).
• The need to use durable casings (steel, cast iron and copper).
• Low fatigue resistance (reduces the performance of the element and shortens the service life).
• High level of thermal conductivity.

• Presence of additives from bismuth and arsenic (not suitable for secondary use, only disposal).
• When using tin babbits, the final cost of the bearing is sometimes very high.

Results

Despite the fact that these alloys of babbitt have certain disadvantages, they have gained recognition and are used in many areas of mechanical engineering. The positive properties of such compounds make it possible to solve even the most complex engineering problems.