C109 / CW118C /Tellurium Copper
C109 / CW118C is a free machining tellurium containing alloy that retains the high conductivity values associated with pure copper. The machining characteristics of the copper are significantly improved by alloying it with approximately half per cent of tellurium, while the electrical and thermal conductivity are only slightly reduced.
The tellurium forms a small precipitate that is evenly distributed throughout the microstructure and acts as a chip breaker causing the swarf to break into short pieces. The alloy offers a machinability rating of ~90% (free cutting brass = 100) versus a standard copper machinability rating of ~20%. This allows the C109 / CW118C to be machined at a much higher speed with lower tool wear, giving machinists and designers a more cost effective product.
Tellurium copper is manufactured by refining, melting and casting the material in to billets for the manufacture of the final product. It is essential that any oxygen is eliminated at this stage to give a resistance to hydrogen embrittlement and prevent any oxygen combining with tellurium that would make the copper brittle.
Chemical Composition
Copper |
Rem |
Tellurium |
0.4–0.7% |
Phosphorus |
0.003-0.012% |
Total Imps |
0.1% max |
Related Specifications
C109 |
C14500 |
CW118C |
CuTe |
DIN 2.1546 |
|
Key Features
- Excellent Electrical Conductivity
- Free Machinability
- Freedom from Hydrogen Embrittlement
- Very Good thermal conductivity
Typical Physical Properties
Melting Point |
1081°C |
Density |
8.9 g/cm³ |
Specific heat |
385 J/Kg °K |
Thermal conductivity |
370 W/m°C |
Thermal expansion coefficient (20-200°C) |
17.0 x 10-6 |
Electrical conductivity |
94 % IACS |
Electrical resistivity |
0.0187 microhm m |
Modulus of elasticity |
12500 Kg/mm² |
Fabrication Properties
Hot Working Temperature Range |
725-825°C |
Hot Formability |
Good |
Cold Formability |
Good |
Cold reduction between anneals |
70% max. |
Machinability rating (free cutting brass = 100) |
85-90% |
Joining Methods
Soldering |
Excellent |
Brazing |
Good |
Oxy-acetylene welding |
Not Recommended |
Gas-shielded arc welding |
Fair |
Resistance welding: Spot and Seam Butt |
Not recommended
Fair |
Typical Uses:
Traditional uses for C109 / CW118C Tellurium Copper are electrical components that require extensive or intricate machining including electrical switches for power semi-conductors, transformer and circuit breaker terminals, gas cutting nozzles, contacts, clamps, electrical connector pins, bolts, nuts, studs and other components requiring free machinability.
This technical information is given by John Hood & Co.without charge and the user shall employ such information at their own discretion and risk. For more detailed technical advice on temper selection, fabrication, joining, machining, physical and mechanical data please contact us as space does not permit the listing of every feature of the material.