Description
Manganese bronze alloys incorporate minor amounts of manganese, iron, and aluminum, along with the inclusion of lead to enhance lubrication, prevent seizing, and promote bonding. Similar to aluminum bronzes, manganese bronze alloys effectively blend high tensile strength with outstanding resistance to corrosion. Manganese bronze bearings are capable of performing efficiently at elevated speeds and while bearing heavy loads. However, it’s essential to note that they necessitate high shaft hardness and must operate under nonabrasive conditions to maintain their performance.
Chemical Composition
| Elements | Min (%) | Max (%) |
| Cu | 56.00 | 60.00 |
| Pb | 0.50 | 1.50 |
| Sn | 0.60 | 1.10 |
| Fe | 0.30 | 1.25 |
| Mn | 0.50 | 2.00 |
| Al | – | 0.20 |
| Total Others | – | 0.50 |
| Zn | Remainder |
Mechanical Properties According To 6912 FHTB1 (As Per Temper HB)
| Range (mm) |
From |
To |
UTS Min (MPa) |
PS Min (MPa) |
Elongation Min (%) |
Hardness Min |
Hardness Max |
| Round (Dia) | 1.5 | 75 | 430 | 180 | 15 | – | – |
| Hex (A/F) | 3 | 70 | 430 | 180 | 15 | – | – |
| Square (A/F) | 3 | 60 | 430 | 180 | 15 | – | – |
| Rectangle (Thickness) | 3 | 50 | 430 | 180 | 15 | – | – |
Physical Properties
| Melting Point – Liquidus°F | 1630 |
| Melting Point – Solidus°F | 1590 |
| Densitylb/cu in. at 68°F | 0.302 |
| Specific Gravity | 8.36 |
| Electrical Conductivity% IACS at 68°F | 24 |
| Thermal ConductivityBtu/ sq ft/ ft hr/ °F at 68°F | 61 |
| Coefficient of Thermal Expansion 68-57210⁻⁶ per °F (68 – 572°F) | 11.8 |
| Specific Heat CapacityBtu/ lb /°F at 68°F | 0.09 |
| Modulus of Elasticity in Tensionksi | 15000 |
| Modulus of Rigidity ksi | 5600 |
Fabrication Properties
| Technique |
Suitability |
| Soldering | Excellent |
| Brazing | Excellent |
| Oxyacetylene Welding | Good |
| Gas Shielded Arc Welding | Fair |
| Coated Metal Arc Welding | Not Recommended |
| Spot Weld | Good |
| Seam Weld | Fair |
| Butt Weld | Good |
| Capacity for Being Cold Worked | Poor |
| Capacity for Being Hot Formed | Excellent |
| Forgeability Rating | 80 |
| Machinability Rating | 30 |
