Sep 18 2012
Topics Covered
IntroductionChemical CompositionPhysical PropertiesMechanical PropertiesThermal PropertiesFabrication and Heat Treatment Machinability Welding Hot Working Cold Working Annealing
Introduction
Pure copper has good electrical and thermal conductivity. More than 400 varieties of copper alloys are available. The UNS C78200 leaded nickel silver copper alloy has high corrosion resistance, and good formability.
The following datasheet gives an overview of UNS C78200 copper alloy.
Chemical Composition
The chemical composition of UNS C78200 copper alloy is given in the following table.
| Element |
Content (%) |
| Cu |
65 |
| Pb |
2 |
| Zn |
25 |
| Ni |
8 |
Physical Properties
The physical properties of UNS C78200 copper alloy are tabulated below.
| Properties |
Metric |
Imperial |
| Density |
8.69 g/ cm3 |
0.314 lb/in³ |
Mechanical Properties
The following table shows the mechanical properties of UNS C78200 copper alloy.
| Properties |
Metric |
Imperial |
| Tensile strength |
362-627 MPa |
52500-90900 psi |
| Yield strength (depending on temper) |
159-524 MPa |
23100-76000 psi |
| Elongation at break (in 76.2 mm) |
40% |
40% |
| Elastic modulus |
117 GPa |
17000 ksi |
| Poisson’s ratio |
0.34 |
0.34 |
| Machinability (UNS C36000 (free-cutting brass) = 100) |
60 |
60 |
| Shear modulus |
44 GPa |
6380 ksi |
Thermal Properties
The thermal properties of UNS C78200 copper alloy are outlined in the following table.
| Properties |
Metric |
Imperial |
| Thermal expansion co-efficient (@ 20-100°C/68-212°F) |
18.5 µm/m°C |
10.3 µin/in°F |
| Thermal conductivity (@ 20°C/ 68°F) |
48.0 W/mK |
333 BTU in/hr.ft.°F |
Fabrication and Heat Treatment
Machinability
The machinability rating of UNS C78200 copper alloy is 60.
Welding
UNS C78200 copper alloy can be welded using brazing, soldering, and butt welding techniques. Gas shielded arc welding, oxyacetylene welding, spot welding, coated metal arc welding, and seam welding techniques are not suitable for welding this alloys.
Hot Working
UNS C78200 copper alloy has poor hot forming capacity.
Cold Working
UNS C78200 copper alloy has good cold working capacity.
Annealing
Annealing of UNS C78200 copper alloy can be performed at temperatures ranging from 500 to 622°C (930 to 1150°F).