C75200 nickel silver is also known as 65-18-18 nickel silver or German silver. It comprises 65% copper, 18% nickel, and 18% zinc. The small amount of lead added to the alloy improves its machinability. The alloy has a silver-white colour and is often used in applications where a silver-like appearance is needed.
| Element | Content (%) |
|---|---|
| Cu | 65 |
| Zn | 17 |
| Ni | 18 |
C75200 nickel silver has a density of 8.8 g/cm³ and a melting point of 1050°C. It has a coefficient of thermal expansion of 18.4 x 10-6/K and a thermal conductivity of 24 W/m.K. The alloy has excellent electrical conductivity, making it a popular material for producing electrical and electronic components.
| Properties | Metric | Imperial |
|---|---|---|
| Density | 8.73 g/cm³ | 0.315 lb/in³ |
| Melting point | 1070°C | 1960°F |
C75200 nickel silver has high strength and good ductility. Its ultimate tensile strength is 620 MPa, and its yield strength is 340 MPa. The alloy's elongation at break is 35%, making it easily formable. It also exhibits good fatigue resistance, making it a reliable material for applications that experience cyclic loading.
| Properties | Metric | Imperial |
|---|---|---|
| Tensile strength | 386-710 MPa | 56000-103000 psi |
| Yield strength (depending on temper) | 172-621 MPa | 24900-90100 psi |
| Elongation at break ( in 76.2 mm) | 45% | 45% |
| Elasticity modulus | 117 GPa | 17000 ksi |
| Poisson's ratio | 0.34 | 0.34 |
| Machinability (UNS C36000 (free-cutting brass) = 100) | 20 | 20 |
| Shear modulus | 47 GPa | 6820 ksi |
| Properties | Metric | Imperial |
|---|---|---|
| Thermal expansion co-efficient (@ 20-300 °C/680-572°F) | 16.2 µm/m°C | 9.00 µin/in°F |
| Thermal conductivity (@ 20°C/68°F) | 33 W/mK | 229 BTU in/hr.ft².°F |
C75200 nickel silver is used in various applications, including tableware, musical instruments, jewellery, and decorative items. It also produces electrical and electronic components like connectors, switches, and relays. The alloy's aesthetic appeal and excellent corrosion resistance make it popular in producing architectural hardware, such as door handles, locks, and hinges.
C75200 nickel silver has a hardness of 140-180 HV. The alloy can be hardened by cold working, which improves its strength and wear resistance. However, the alloy's ductility decreases as its hardness increases.
C75200 nickel silver can be annealed to improve its ductility and machinability. The alloy should be heated to 650°C and then cooled slowly in the air. This will eliminate any residual stresses in the material and improve its formability.
C75200 nickel silver can be welded using resistance welding or gas welding. However, the alloy's lead content can release toxic fumes during welding, making it important to use proper ventilation and protective equipment.
C75200 nickel silver has excellent corrosion resistance in both freshwater and seawater environments. The alloy's high copper content provides natural antimicrobial properties, making it popular in cooking kitchen utensils and medical equipment. However, the alloy is unsuitable for acidic or strongly oxidizing.
