Choosing the right Babbitt alloy helps to increase a bearing’s useful life
Reliable machine operation depends on a properly working bearing assembly. If there is a failure within the bearing, such as a decrease in lubrication, the resulting heat from friction can not only decrease the life of the bearing but also cause equipment to break down, racking up costly repair bills and unscheduled downtime. To ensure a bearing will have a long service life, it must be made of a material that can endure specific working conditions.
Babbitt alloys are a common choice for bearings. Isaac Babbitt created the first Babbitt alloy in 1839. It was made up of 89 percent Tin, 9 percent Antimony and 2 percent Copper and was closely related to ASTM B-23 Grade 2. When evaluating Babbitt alloys, companies should consider the surface speed of the shaft and the load the bearing will be required to carry. A high-Tin alloy should be used for highly loaded bearings and Lead-based alloys can be a more economical choice for slower-speed work and lighter loads. In cases where repair and rebuilding of existing bearings is needed, it is important to try to replicate the original Babbitt alloy.
For 90 years Jackson Wheeler has been manufacturing a wide variety of Tin-based and Lead-based Babbitt alloys. Belmont Metals acquired the company in 1996 and continues to manufacture the complete line of Jackson Wheeler products, including Tuftin and Tuftex.
Tuftin and Tuftex are trade names for families of Nickel-Copper-toughened Babbitt bearing alloys. Tuftin alloys are Tin-based, Lead-free, heavy-duty bearing materials. Applications for Tuftin include those where high pressure, heat and speed are factors, including heavy machinery, electric motors, steam locomotives and compressors. Tuftin alloys are manufactured by alloying Nickel and Copper into a Tin-Antimony matrix, resulting in a material that’s tough, malleable, corrosion and impact-resistant, and has a dense grain structure. Tuftin comes in several compositions to meet the needs of a variety of industries: Tuftin No. 73 Nickel Alloy, Tuftin Nickel Genuine No. 1, Tuftin Navytex for shock load applications in marine work and Tuftin Duratin.
Tuftex Rollite is a good choice for general-purpose applications. Rollite is composed of Nickel, Copper, Tin, Antimony and Lead—a combination that provides efficient operation and long wear. Another Tuftex alloy, Lubrite, is hardened and toughened with pure Nickel, which, along with Tin and Antimony, is alloyed into a Lead matrix. Lubrite has a fine, uniform grain structure and is best suited for bearings that will sustain heavy, steady loads under hot and gritty conditions, such as the ones found in cement machinery, conveyors, farm equipment and steel mill machinery. Tuftex alloys also include Tuftex Duratex, Tuftex Chipper Alloy, Tuftex 4x Alloy, and Tuftex Gib Shoe Alloy.
The formulations in modern Babbitt alloys are the result of years of research and testing. Because of these efforts, there are Babbitts available for a wide variety of bearing types. For comparison purposes, manufacturers can consult standards from the American Society for Testing and Materials, which catalogs eight grades of Babbitt alloys, in addition to collaborating with a metallurgist or trusted alloy manufacturer for technical support and advice.