Description
C31400 Leaded Commercial Bronze is a type of free-machining brass known for its exceptional electrical and thermal conductivity. This alloy also exhibits resistance to corrosion. Notably, it contains 2.00% lead, which imparts excellent free-cutting properties, making it well-suited for applications where ease of machining and good electrical and thermal conductivity are required.
Chemical Composition
| Elements | Min (%) | Max (%) |
| Cu | 87.50 | 90.50 |
| Pb | 1.30 | 2.50 |
| Fe | – | 0.10 |
| Ni | – | 0.70 |
| Total Others | – | 0.40 |
| Zn | Remainder |
Mechanical Properties According To C31400 ASTMB 140 (As Per Temper HO2)
| Range (Inch) |
From |
To |
UTS Min (ksi) |
PS Min (ksi) |
Elongation Min (%) |
Hardness Min |
Hardness Max |
| Round (Dia) |
0.059 |
0.500 |
50 |
30 |
7 |
– |
– |
| 0.500 |
1.000 |
45 |
27 |
10 |
– |
– |
| 1.000 |
2.953 |
40 |
25 |
12 |
– |
– |
| Hex (A/F) |
0.118 |
0.500 |
50 |
30 |
7 |
– |
– |
| 0.500 |
1.000 |
45 |
27 |
10 |
– |
– |
| 1.000 |
2.756 |
40 |
25 |
12 |
– |
– |
| Square (A/F) |
0.118 |
2.362 |
40 |
25 |
12 |
– |
– |
| Rectangle |
Thickness |
0.118 |
1.000 |
40 |
25 |
12 |
– |
– |
| Width |
0.157 |
2.000 |
| Thickness |
1.000 |
1.968 |
40 |
25 |
12 |
– |
– |
| Width |
1.000 |
2.756 |
| Range (mm) |
From |
To |
UTS Min (MPa) |
PS Min (MPa) |
Elongation Min (%) |
Hardness Min |
Hardness Max |
| Round (Dia) |
1.5 |
12 |
345 |
205 |
7 |
– |
– |
| 12 |
25 |
310 |
185 |
10 |
– |
– |
| 25 |
75 |
275 |
170 |
12 |
– |
– |
| Hex (A/F) |
3 |
12 |
345 |
205 |
7 |
– |
– |
| 12 |
25 |
310 |
185 |
10 |
– |
– |
| 25 |
70 |
275 |
170 |
12 |
– |
– |
| Square (A/F) |
3 |
50 |
275 |
170 |
12 |
– |
– |
| Rectangle |
Thickness |
3 |
25 |
275 |
170 |
12 |
– |
– |
| Width |
4 |
50 |
| Thickness |
25 |
50 |
275 |
170 |
12 |
– |
– |
| Width |
50 |
70 |
Physcial Properties
| Melting Point – Liquidus°F |
1900 |
| Melting Point – Solidus°F |
1850 |
| Density lb/cu in. at 68°F |
0.319 |
| Specific Gravity |
8.83 |
| Electrical Conductivity% IACS at 68°F |
42 |
| Thermal Conductivity Btu/ sq ft/ ft hr/ °F at 68°F |
104 |
| Coefficient of Thermal Expansion 68-57210⁻⁶ per °F (68 – 572°F) |
10.2 |
| Specific Heat Capacity Btu/ lb /°F at 68°F |
0.09 |
| Modulus of Elasticity in Tension ksi |
17000 |
| Modulus of Rigidity ksi |
6400 |
Fabrication Properties
| Technique |
Suitability |
| Soldering |
Excellent |
| Brazing |
Good |
| Oxyacetylene Welding |
Not Recommended |
| Gas Shielded Arc Welding |
Not Recommended |
| Coated Metal Arc Welding |
Not Recommended |
| Spot Weld |
Not Recommended |
| Seam Weld |
Not Recommended |
| Butt Weld |
Fair |
| Capacity for Being Cold Worked |
Good |
| Capacity for Being Hot Formed |
Poor |
| Machinability Rating |
80 |
