Babbitt is a family name for soft bearing alloys rather than one fixed composition. Tin-base and lead-base grades have different chemistry and melting ranges, and supplier grade names must be matched to the supplier’s actual specification. This table summarizes selected Belmont Metals product data. It is a product comparison, not a complete standard specification or a bearing design allowable.

Babbitt White Metal Bearing Alloy Compositions

Compare the base-metal families

The selected Grade 1, Grade 2, and Grade 3 products are tin-base alloys. Their listed tin content ranges from 84% to 91%, with antimony and copper making up the other principal additions. Grades 8, 13, and 15 are lead-base alloys with different amounts of tin and antimony; Grade 8 also lists arsenic. The percentages are by weight and describe the manufacturer’s named products, not every alloy that may be sold using a similar grade label.

The listed solidus and liquidus values mark the lower and upper parts of the melting interval. The interval is not a recommended pouring temperature. A foundry process needs its own temperature control, equipment, and procedure. The difference between the two temperatures varies across these products, so one grade’s process setting should not be copied to another grade without supplier confirmation.

Do not treat grade names as interchangeable

A familiar designation does not prove that two sources use identical limits or chemistry. Compare the supplier, product code, composition range, certificate, and applicable purchase specification. Belmont’s page lists the shown product codes with its composition and temperature data. For procurement, request current certification and verify the delivered lot against the drawing and governing standard.

ASTM B23 covers white-metal bearing alloys, but the rows here are only a selected supplier subset. The table is not a full reproduction of the standard and does not provide every permitted composition, mechanical property, or application limit. Use the current edition of the applicable standard and the supplier documentation for acceptance. Confirm whether the bearing design calls for a tin-base or lead-base material and whether the specified grade is supported by the foundry process.

Composition does not determine bearing performance alone

Alloy composition is only one input to a bearing decision. The backing material, bonding method, lining thickness, shaft finish, clearance, lubrication regime, load, speed, start-stop duty, temperature, contamination, and alignment all matter. A composition table cannot predict fatigue life or establish a safe load. Use the bearing designer’s calculations and the supplier’s engineering data for the actual application.

For an existing bearing, identify the material from traceable records rather than appearance alone. A repair or relining operation should preserve the required bond and geometry, and the responsible engineer should approve the material substitution. If a product name or code has changed, ask the supplier for written confirmation of equivalency and retain the supporting certificate with the maintenance record.

Handle lead and arsenic with controls

Several rows contain substantial lead, and the Grade 8 listing includes arsenic. These substances can create serious exposure and environmental hazards during melting, pouring, machining, cleanup, and disposal. Facilities should follow applicable occupational exposure rules, use appropriate ventilation and personal protective equipment, control contaminated dust, and manage waste under local requirements. A material comparison should never be used as a substitute for a site-specific hazard assessment.

When selecting a product for new equipment, consider whether the application permits a lead-bearing alloy and whether an alternative material is technically and legally suitable. Do not assume that a lower listed lead percentage automatically makes an alloy safe to handle without controls.

References

• Belmont Metals: Babbitt Metals product listings
• ASTM B23-20(2025), Standard Specification for White Metal Bearing Alloys

Use current supplier certification and the applicable standard for material acceptance. Confirm the bearing geometry, service conditions, and exposure controls before production or repair.