Specific weight of Babbitt, its properties, grades and value table

Babbitt is an antifriction alloy based on lead and tin. The main purpose of this type of material is to use it as a layer sprayed or cast onto the surface of a plain bearing liner. This material was named after its creator, Isaac Babbitt.

Table of the specific weight of Babbitt

Since Babbitt is a complex material, it is not possible to calculate its specific weight independently in field conditions. These calculations are carried out in special chemical laboratories. However, the average specific weight of Babbitt is known and ranges from 7.3 to 10.1 g/cm³.

To simplify the calculations, below is a table with the values of the specific weight of Babbitt, as well as such a parameter as the weight of Babbitt depending on the units of calculation.

Properties of Babbitt

By chemical composition, Babbitt is divided into three groups depending on the percentage ratio of components:

• The composition of the first group is 10 percent copper and 90 percent tin
• The composition of the second group is 4 percent copper, 7 percent antimony and 89 percent tin
• The composition of the third group is 5 percent tin, 15 percent antimony and 80 percent lead

The first two groups, with a predominance of tin, are used to produce antifriction material with increased viscosity and a low coefficient of friction. Tin-based Babbitt, compared with lead-based Babbitt, is characterized by high wear resistance, corrosion resistance and thermal conductivity.

The third lead-based group is used for bearings in rolling mills, diesel engines and other heavily loaded sliding units. Operating limits depend on the grade, load, sliding speed, cooling and lubrication, so lead-based and tin-based Babbitts should be compared by the specific material specification.

To give the necessary properties, alloying additives such as copper, arsenic, antimony, nickel, tellurium, sodium, cadmium, calcium and magnesium may be used. The melting temperature of Babbitt ranges from 300 to 440 °C.

Babbitt can be produced with the addition of calcium for use in railway transport bearings.

The main disadvantage of all groups of Babbitt alloys is low fatigue resistance, because of which products made from this material often lose their operating performance. Trying to compensate for this drawback, manufacturers use it only when creating bearings with a bronze or cast-iron-and-steel housing.

The service life of the product depends on the thickness of the Babbitt layer: the thinner the layer, the longer such a product will last.

Grades of Babbitt

There are three main grades of Babbitt:

• Babbitt grade B-83. This grade is an alloy with the following ratio of elements: copper - 6 percent, antimony - 11 percent, tin - 83 percent. The main purpose of this grade is to create bearings for medium loads with an allowable operating pressure from 10 to 15 MPa.
• Babbitt grade B-16. This grade is an alloy with the following ratio of elements: copper - from 1.5 to 2 percent, antimony - from 15 to 17 percent, tin - from 15 to 17 percent, and the rest is lead. The main purpose of this grade is to create bearings for parts of steam locomotives, electric locomotives and track machines, as well as other types of heavy engineering, with an allowable operating pressure of 10 MPa.
• Babbitt grade SOS6. This grade is an alloy with the following ratio of elements: zinc - from 5.5 to 6.5 percent, antimony - from 5.5 to 6.5 percent, and lead - the remaining percentage. The main purpose of this grade is to create bearings for high loads with an allowable operating pressure of 20 MPa and a temperature of more than 300 °C.