ASTM B702 Tungsten-Copper Electrical Contact Material
- Grade: Class A (WCu 50/50), Class B (WCu60/40), Class C (WCu70/30), Class D (WCu 75/25), Class E (WCu 80/20)
WCu 55/45, WCu 56/40, WCu 65/35, WCu 68/32, WCu 68/32 HT, WCu 75/25 HT, WCu 78/22, WCu 85/15, WCu 90/10 - Shapes: Plate, Sheet, Rod, Bar, Tube, Wire
ASTM B702 Tungsten-Copper Electrical Contact Material
Golden Sunbird Metals supplies premium ASTM B702 tungsten-copper electrical contact material (WCu) in five standard classes — Class A (50/50), Class B (60/40), Class C (70/30), Class D (75/25), and Class E (80/20) — plus additional high-performance grades manufactured by powder metallurgy for superior arc erosion resistance and thermal management. Available in plate, sheet, rod, bar, tube, and wire forms with custom dimensions (plate up to 50 mm thick × 1000 mm wide; rod up to 100 mm diameter; wire from 0.01 mm), these materials combine the high conductivity of copper with the high melting point and hardness of tungsten, delivering excellent electrical and thermal performance, low thermal expansion, and outstanding machinability. Ideal for switchgear components, circuit breakers, relays, EDM and resistance-welding electrodes, heat sinks, semiconductor base plates, and medical X-ray tube parts. Our ASTM B702-compliant tungsten-copper products meet the highest industry standards with full EN 10204 3.1/3.2 mill test certification. Request a quote today for custom compositions, dimensions, and fast global delivery.
Chemical Composition (wt.%) of Tungsten-Copper
| Elements | Class A | Class B | Class C | Class D | Class E |
| Copper, % | 48–52 | 38–42 | 28–32 | 23–27 | 18–22 |
| Tungsten, % | balance | balance | balance | balance | balance |
| Additives (Individual or total), max, % | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
Physical Properties of Tungsten-Copper
| Hardness, Rockwell B | 69–83 | 77–90 | 85–98 | 89–102 | 94–106 |
| Density, Mg/m³ at 96% theoretical | 11.7 | 12.7 | 13.7 | 14.3 | 15 |
| Electrical Conductivity, C % IACS | 56–64 | 49–57 | 44–52 | 41–48 | 38–45 |
| Electrical Conductivity, D % IACS | 38–56 | 34–49 | 29–43 | 27–41 | 25–37 |
| Tensile Strength, ksi (MPa) | 50–60 (344–413) | 55–65 (379–448) | 75–85 (516–585) | 85–95 (585–654) | 90–100 (620–689) |
| Modulus of Rupture, ksi (MPa) | 75–85 (517–586) | 110–120 (758–827) | 130–140 (896–965) | 140–150 (965–1034) | 150–160 (1034–1103) |
| Coefficient of Expansion, in./in. | 7.2 x 10-6 | 6.6 x 10-6 | 5.7 x 10-6 | 5.3 x 10-6 | 4.9 x 10-6 |
| °F m/m·K | 13 x 10-6 | 11.9 x 10-6 | 10.3 x 10-6 | 9.5 x 10-6 | 8.8 x 10-6 |
Features
- ASTM B702 copper-tungsten electrical contact material manufactured by powder metallurgy for high-performance contact components.
- Available in Class A to Class E, with copper content ranging from 48–52% down to 18–22%, and tungsten as the balance.
- High electrical conductivity and high thermal conductivity for efficient current transfer and heat dissipation.
- Excellent arc erosion resistance, high melting point, and low thermal expansion for stable performance under heavy electrical load.
- Good mechanical strength and machinability for precision contact parts and custom components.
- Available in plate, sheet, rod, bar, tube, and wire forms for different fabrication needs.
Technical Specifications
| Specification | Value |
| Standard | ASTM B702 Copper-Tungsten Electrical Contact Material |
| Grade | Class A (WCu 50/50), Class B (WCu60/40), Class C (WCu70/30), Class D (WCu 75/25), Class E (WCu 80/20) WCu 55/45, WCu 56/40, WCu 65/35, WCu 68/32, WCu 68/32 HT, WCu 75/25 HT, WCu 78/22, WCu 85/15, WCu 90/10 |
| Type | Plate, Sheet, Rod, Bar, Tube, Wire |
| Finish | Clean, smooth surface finish |
| Dimension | Plate Thickness: 1-50 mm x Width: 50-1000 mm x Length: 50-2000 mm Sheet Thickness: 0.5-10 mm x Width: 50-1000 mm x Length: 50-2000 mm Rod Diameter: 2-100 mm x Length: 50-2000 mm Bar Width: 5-200 mm x Thickness: 5-100 mm x Length: 50-2000 mm Tube OD: 5-150 mm x WT: 0.5-10 mm x Length: 50-2000 mm Wire Diameter: 0.01 – 20mm |
| Manufacturing Process | Plate and Sheet: Hot-rolled, Cold-rolled |
| Rod and Bar: Hot-rolled, Cold-rolled | |
| Inspection Certificate | EN 10204 Type 3.1 (Mill Test Certificate), EN 10204 Type 3.2 (Witness Testing or 3rd Party Inspection) |
| Tests | Chemical analysis, tensile test, hardness test, and other non-destructive test (Hydrostatic, Pneumatic, and Ultrasonic tests) |
Applications
- Switchgear components such as circuit breakers, relays, and switches.
- EDM electrodes and resistance-welding electrodes.
- Heat sinks, base plates, and thermal-management parts for power modules and semiconductor devices.
- Busbars, conductors, and high-current power-distribution contacts.
- X-ray tube components and other medical-device parts that need good thermal control.
