Tungsten Alloy W80Cu20-SI
Heat-treated state · default condition
also CuW80
SI = pressed, sintered and copper-infiltrated
Default commercial condition for EDM electrodes, contacts and heat spreaders; best balance of density, hardness and conductivity.
Values for the SI condition
Other W80Cu20 tempers and conditions
W80Cu20 is listed in 5 conditions; see the grade overview at W80Cu20.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solid-state pressed and sintered | Lower-cost route for large blanks and non-critical parts; slightly lower density and conductivity due to residual porosity. | 420 | 540 | 2 | 14 HRC | 30 % IACS |
RWMA Class 12 | Specify when buying to RWMA/ANSI classification for projection-welding inserts, flash-welding dies and facing electrodes. | 450 | 600 | 2 | 18 HRC | 29 % IACS |
SIDefaultThis page Pressed, sintered and copper-infiltrated | Default commercial condition for EDM electrodes, contacts and heat spreaders; best balance of density, hardness and conductivity. | 470 | 630 | 3 | 18 HRC | 34 % IACS |
Fine-grain EDM electrode grade | Fine, uniform tungsten grain size for low electrode wear and mirror-quality EDM finishes in carbide and hardened steel. | 490 | 650 | 3 | 19 HRC | 34 % IACS |
Hot isostatic pressed | Choose for vacuum interrupter contacts and high-reliability electrodes where residual porosity and gas content must be minimised. | 520 | 720 | 4 | 220 HB | 36 % IACS |
What is W80Cu20-SI?
W80Cu20-SI is W80Cu20 heat treated to SI — default commercial condition for EDM electrodes, contacts and heat spreaders; best balance of density, hardness and conductivity. W80Cu20-SI has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 630 MPa (91.4 ksi) — weaker than 94% of tungsten alloy grades. Elongation at break is 3% and the elastic modulus is 260 GPa (37.7 Msi). W80Cu20-SI has a density of 15.25 g/cm³ (0.551 lb/in³), lighter than 81% of tungsten alloy grades. It melts at 1,083°C (1,981 °F).
Advantages
- Low embodied carbon — 14 kg CO₂/kg, better than 100% of tungsten alloy grades
- Conducts heat well — 190 W/m·K (109.8 BTU/hr·ft·°F), better than 95% of tungsten alloy grades
- High electrical conductivity — 34 % IACS, better than 95% of tungsten alloy grades
- Easy to machine — 30/100, better than 86% of tungsten alloy grades
- Lightweight — 15.25 g/cm³ (0.551 lb/in³), better than 81% of tungsten alloy grades
Limitations
- Low stiffness — 260 GPa (37.7 Msi), worse than 95% of tungsten alloy grades
- Low strength — 470 MPa (68.2 ksi), worse than 94% of tungsten alloy grades
W80Cu20-SI properties
Typical room-temperature values for W80Cu20-SI; 24 are specific to this condition. Other listed values are W80Cu20 reference data and may not represent this condition. Bars are the position among tungsten alloy grades.
Physical3
W80Cu20-SI has a density of 15.25 g/cm³ (0.551 lb/in³), lighter than 81% of tungsten alloy grades. It melts at 1,083°C (1,981 °F).
Mechanical17
W80Cu20-SI has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 630 MPa (91.4 ksi) — weaker than 94% of tungsten alloy grades. Elongation at break is 3% and the elastic modulus is 260 GPa (37.7 Msi).
Thermal5
W80Cu20-SI is rated for continuous service to 500°C (932 °F). It conducts heat at 190 W/m·K (109.8 BTU/hr·ft·°F), better than 95% of tungsten alloy grades. Thermal expansion is 8.3 µm/m·K (4.61 µin/in·°F).
Electrical3
W80Cu20-SI conducts electricity at 34 % IACS, better than 95% of tungsten alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 62% of tungsten alloy grades.
Sustainability4
Producing a kilogram of W80Cu20-SI takes about 190 MJ of energy and emits 14 kg of CO₂ — less than 100% of tungsten alloy grades. Typical recycled content is 30%.
Manufacturability7
W80Cu20-SI's machinability is poor (30/100, better than 86% of tungsten alloy grades); weldability not recommended (10/100); formability not recommended (5/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with W80Cu20-SI
Is W80Cu20 easy to machine?
Turn/mill with sharp carbide or PCD tooling at low feed, flood coolant; grinding, wire EDM and sinker EDM are the preferred finishing routes for tight tolerance.
Can W80Cu20 be welded?
Not fusion weldable — join by silver-copper brazing or resistance backing to a copper holder; avoid overheating that sweats copper out of the skeleton.
Can W80Cu20 be formed, bent or molded?
No cold or hot forming; parts are made near-net by pressing/sintering/infiltration and finished by machining or EDM.
What surface finishes work on W80Cu20?
Degrease and pickle lightly, then nickel or silver plate for solderability and tarnish resistance; surfaces polish well but porosity in sintered-only grades can retain fluids.
W80Cu20 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 |
|---|---|---|
| Wsintered tungsten skeleton | 78 – 82 | 80 |
| Impurities (total)Fe, Ni, C, O per GB/T 8320 | ≤ 0.5 | 0.2 |
| Cuinfiltrant, balance | ≥ 18 (balance) | — |
W80Cu20-SI — frequently asked
What is W80Cu20-SI used for?
W80Cu20-SI is typically used for EDM electrodes for hardened dies, vacuum interrupter contacts and rocket nozzle throat inserts. In short: harder than CuW70; high arc-erosion resistance; fine-detail EDM electrode.
What is the yield strength of W80Cu20-SI?
W80Cu20-SI has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 630 MPa (91.4 ksi) — weaker than 94% of tungsten alloy grades. Strength varies by condition: see the 5 listed tempers.
Is W80Cu20-SI easy to machine?
Not especially — machinability is rated poor (30/100, better than 86% of tungsten alloy grades). Turn/mill with sharp carbide or PCD tooling at low feed, flood coolant; grinding, wire EDM and sinker EDM are the preferred finishing routes for tight tolerance.
Can W80Cu20-SI be welded?
Not readily — weldability is rated not recommended (10/100). Not fusion weldable — join by silver-copper brazing or resistance backing to a copper holder; avoid overheating that sweats copper out of the skeleton.
What surface finishes work on W80Cu20-SI?
Degrease and pickle lightly, then nickel or silver plate for solderability and tarnish resistance; surfaces polish well but porosity in sintered-only grades can retain fluids.
Can W80Cu20-SI be formed, bent or molded?
No cold or hot forming; parts are made near-net by pressing/sintering/infiltration and finished by machining or EDM.
What is the maximum service temperature of W80Cu20-SI?
W80Cu20-SI is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between W80Cu20-SI and W80Cu20-HIP?
SI is the default condition — default commercial condition for EDM electrodes, contacts and heat spreaders; best balance of density, hardness and conductivity. HIP: choose for vacuum interrupter contacts and high-reliability electrodes where residual porosity and gas content must be minimised. Yield strength is 470 MPa in SI versus 520 MPa in HIP.
Sources
- GB/T 8320 (2003)
- ASTM B702 / RWMA Class 10-13 Copper-Tungsten Electrode Materials — ASTM / RWMA (2017)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Copper-tungsten (W-Cu) composite datasheets — Plansee / / (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.