W75Cu25 FG
Grade
ASTM B694
FG = fine-grain / high-uniformity EDM electrode grade
Choose the 1–3 µm fine-tungsten infiltrated grade for precision EDM electrodes and micro cavities: the uniform structure polishes to a mirror finish, at 190 W/m·K and 3% elongation.
Values for the FG condition
Other W75Cu25 grades and fills
W75Cu25 is listed in 4 conditions; see the grade overview at W75Cu25.
Compare all 4 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
INFDefault Press-sinter-infiltrated | Pick the press-sinter-infiltrated standard contact grade (ASTM B702 Class 75W) when arc erosion resistance must balance 200 W/m·K conduction, for HV switch contacts and general EDM electrodes. | 380 | 620 | 5 | — |
Activated press-and-sinter | Use the lower-cost Ni/Co-activated press-and-sinter route when 650 MPa strength matters more than conduction; activator dissolved in the copper cuts thermal conductivity to 165 W/m·K. | 420 | 650 | 3 | — |
Hot isostatic pressed | Pick hot isostatically pressed stock for microwave tubes, IGBT and laser heat sinks and package bases: closed porosity below 0.5% gives the best conduction (215 W/m·K) and hermeticity. | 420 | 680 | 6 | — |
FGThis page Fine-grain / high-uniformity EDM electrode grade | Choose the 1–3 µm fine-tungsten infiltrated grade for precision EDM electrodes and micro cavities: the uniform structure polishes to a mirror finish, at 190 W/m·K and 3% elongation. | 450 | 700 | 3 | — |
What is W75Cu25 FG?
W75Cu25 FG is W75Cu25 in the FG grade — choose the 1–3 µm fine-tungsten infiltrated grade for precision EDM electrodes and micro cavities: the uniform structure polishes to a mirror finish, at 190 W/m·K and 3% elongation. W75Cu25 FG has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 74% of composite grades. Elongation at break is 3% and the elastic modulus is 255 GPa (37 Msi). W75Cu25 FG has a density of 14.9 g/cm³ (0.538 lb/in³), heavier than 101% of composite grades. INF is the default condition FabDigit quotes; FG is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 85/100, better than 99% of composite grades
- Conducts heat well — 190 W/m·K (109.8 BTU/hr·ft·°F), better than 97% of composite grades
- Good UV / weathering resistance — 100/100, better than 93% of composite grades
- Stiff — 255 GPa (37 Msi), better than 88% of composite grades
- High service temperature — 400°C (752 °F), better than 78% of composite grades
Limitations
- Heavy — 14.9 g/cm³ (0.538 lb/in³), worse than 101% of composite grades
- Needs corrosion protection — 50/100, worse than 92% of composite grades
W75Cu25 FG properties
Typical room-temperature values for W75Cu25 FG; 15 are specific to this condition. Other listed values are W75Cu25 reference data and may not represent this condition. Bars are the position among composite grades.
Physical1
W75Cu25 FG has a density of 14.9 g/cm³ (0.538 lb/in³), heavier than 101% of composite grades.
Mechanical11
W75Cu25 FG has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 74% of composite grades. Elongation at break is 3% and the elastic modulus is 255 GPa (37 Msi).
Thermal6
W75Cu25 FG is rated for continuous service to 400°C (752 °F). It conducts heat at 190 W/m·K (109.8 BTU/hr·ft·°F), better than 97% of composite grades. Thermal expansion is 9.5 µm/m·K (5.28 µin/in·°F).
Electrical2
W75Cu25 FG has an electrical resistivity of 4.2×10⁻⁸ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 92% of composite grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of W75Cu25 FG takes about 280 MJ of energy and emits 18 kg of CO₂ — more than 63% of composite grades. Typical recycled content is 20%.
Manufacturability2
W75Cu25 FG's machinability is poor (28/100, worse than 57% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with W75Cu25 FG
Is W75Cu25 easy to machine?
The tungsten phase is strongly abrasive; use sharp carbide or PCD tooling at low speed with a heavier feed and ample coolant. Deep cavities and precision forms are better produced by wire EDM or form grinding.
Can W75Cu25 be welded?
Not fusion weldable — the copper phase melts out and the tungsten does not melt. Braze with BAg silver-copper or Cu-P fillers in vacuum or hydrogen, or resistance-braze onto copper or steel carriers.
Can W75Cu25 be formed, bent or molded?
No cold forming capability. Parts are made net-shape by powder metallurgy (press, sinter, infiltrate), with complex geometry produced by machining or by the PM die shape.
What surface finishes work on W75Cu25?
Ni, Ag or Au plating improves joinability and corrosion resistance. EDM electrode faces are ground or lapped to Ra below 0.4 µm; the material is not suitable for anodizing.
W75Cu25 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Wtungsten skeleton, about 58 vol% | 73 – 77 | 75 |
| Nisintering activator, activated-sintered (PS) grades only | 0 – 0.5 | — |
| Feimpurity | 0 – 0.2 | — |
| other impurities (total)total of C, O, Si and other impurities | 0 – 0.5 | — |
| Cuinfiltrated copper phase, balance | ≥ 23 (balance) | — |
W75Cu25 FG — frequently asked
What is W75Cu25 FG used for?
W75Cu25 FG is typically used for circuit breaker contacts, EDM electrodes, vacuum interrupter contacts and welding electrode tips. In short: arc-erosion contact material; standard EDM electrode grade; very high density.
What is the yield strength of W75Cu25 FG?
W75Cu25 FG has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 74% of composite grades. Strength varies by condition: see the 4 listed tempers.
Is W75Cu25 FG easy to machine?
Not especially — machinability is rated poor (28/100, worse than 57% of composite grades). The tungsten phase is strongly abrasive; use sharp carbide or PCD tooling at low speed with a heavier feed and ample coolant. Deep cavities and precision forms are better produced by wire EDM or form grinding.
Can W75Cu25 FG be welded?
Not fusion weldable — the copper phase melts out and the tungsten does not melt. Braze with BAg silver-copper or Cu-P fillers in vacuum or hydrogen, or resistance-braze onto copper or steel carriers.
What surface finishes work on W75Cu25 FG?
Ni, Ag or Au plating improves joinability and corrosion resistance. EDM electrode faces are ground or lapped to Ra below 0.4 µm; the material is not suitable for anodizing.
Can W75Cu25 FG be formed, bent or molded?
No cold forming capability. Parts are made net-shape by powder metallurgy (press, sinter, infiltrate), with complex geometry produced by machining or by the PM die shape.
What is the maximum service temperature of W75Cu25 FG?
W75Cu25 FG is rated for continuous use to about 400°C (752 °F), and briefly to 1,000°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between W75Cu25 INF and W75Cu25 FG?
INF is the default condition — pick the press-sinter-infiltrated standard contact grade (ASTM B702 Class 75W) when arc erosion resistance must balance 200 W/m·K conduction, for HV switch contacts and general EDM electrodes. FG: choose the 1–3 µm fine-tungsten infiltrated grade for precision EDM electrodes and micro cavities: the uniform structure polishes to a mirror finish, at 190 W/m·K and 3% elongation. Yield strength is 380 MPa in INF versus 450 MPa in FG.
Sources
- ASTM B702 — Copper-Tungsten Electrical Contact Material — ASTM International (2016)
- ASM Handbook Vol.7: Powder Metallurgy (infiltrated W-Cu) — ASM International (2015)
- Tungsten-Copper (W-Cu) material data — Plansee / Mi-Tech Metals (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.