Description
Manganese bronze alloys incorporate minor augmentations of manganese, iron, and aluminum, along with the inclusion of lead to enhance lubrication, prevent seizing, and promote adhesion. Similar to aluminum bronze alloys, they offer a unique amalgamation of high tensile strength and superior resistance to corrosion. Manganese bronze bearings are capable of functioning effectively at elevated speeds while bearing heavy loads, yet they necessitate shafts with elevated hardness and operating environments devoid of abrasiveness.
Chemical Composition
| Elements | Min (%) | Max (%) |
| Cu | 57.00 | 60.00 |
| Pb | 0.30 | 1.20 |
| Si | – | 1.00 |
| Mn | 1.50 | 2.50 |
| Sn | – | 0.50 |
| Fe | – | 0.50 |
| Al | 1.50 | 2.30 |
| Total Others | – | 0.50 |
| Zn | Remainder |
Mechanical Properties According To SAE J463 C67400 (As Per Temper HO2)
| Range (MM) |
From |
To |
UTS Min (Mpa) |
PS Min (Mpa) |
ELo Min (%) |
Hardness Min (HRB) |
Hardness Max (HRB) |
| Round (Dia) |
8 | 75 | 630 | 370 | 8 | 170 | 210 |
| Hex (A/F) |
8 |
70 |
630 |
370 |
8 |
170 |
210 |
| Square |
8 |
60 |
630 |
370 |
8 |
170 |
210 |
| Rectangle (Thickness) |
8 |
50 |
630 |
370 |
8 |
170 |
210 |
Physcial Properties
| Melting Point – Liquidus°F | 1625 |
| Melting Point – Solidus°F | 1590 |
| Density lb/cu in. at 68°F | 0.292 |
| Specific Gravity | 8.08 |
| Electrical Conductivity % IACS at 68°F | 23 |
| Thermal Conductivity Btu/ sq ft/ ft hr/ °F at 68°F | 58 |
| Coefficient of Thermal Expansion 68-57210⁻⁶ per °F (68 – 572°F) | 11 |
| Specific Heat Capacity Btu/ lb /°F at 68°F | 0.09 |
| Modulus of Elasticity in Tension ksi | 16000 |
| Modulus of Rigidity ksi | 6000 |
Fabrication Properties
| Technique |
Suitability |
| Soldering | Fair |
| Brazing | Good |
| Oxyacetylene Welding | Not Recommended |
| Gas Shielded Arc Welding | Fair |
| Coated Metal Arc Welding | Not Recommended |
| Spot Weld | Good |
| Seam Weld | Good |
| Butt Weld | Good |
| Capacity for Being Cold Worked | Poor |
| Capacity for Being Hot Formed | Excellent |
| Forgeability Rating | 100 |
| Machinability Rating | 30 |
