Low-beryllium copper C17510 – UNS C17510
High-conductivity precipitation-hardening copper-nickel-beryllium alloy
Low-beryllium copper alloy (0.2 – 0.6% Be with ≈ 2% Ni) combining electrical conductivity of ≈ 45 – 50% IACS with tensile strength of ≈ 700 – 800 MPa after aging. It conducts heat about twice as well as C17200. It is the classic choice for resistance welding electrodes (RWMA Class 3) and mold inserts that must extract heat quickly.
Designations and equivalents
| System | Designation |
|---|---|
| UNS | C17510 |
| W.Nr./EN | CW110C – CuNi2Be |
| DIN | 2.0850 (CuNi2Be) |
| Trade names | Alloy 3 (Materion), CuNi2Be, RWMA Class 3 |
| Others | MIL-C-81021 (strip); SAE J461/J463 |
Standards by product form
| Form | Standard |
|---|---|
| Bar | ASTM B441 |
| Plate | ASTM B534 (plate, strip and rolled bar) |
| Forging | ASTM B870 (forgings and extrusions) |
| Tube | ASTM B937 (seamless), B944 (welded) |
Tolerances and HS codes
- Forged bars (round and square): machining allowance from 2 mm (Ø 6–16 mm) to 24 mm (Ø 400–500 mm) on the diameter. E.g. Ø 100–125 mm finished: +7 mm, tolerance +6 / −0 (length up to 3,500 mm).
- Forged discs: allowance of 4 to 9 mm on the diameter and 3 to 11 mm on the height, plus-only tolerance.
- Cutting and machining: band saw −0 / +5 to +15 mm on length; waterjet +10 % of thickness on the diameter (min. 2 mm); machined parts −0 / +2 to +5 mm on the diameter. See the full tables (INF 002 and INF 003, the same for every alloy).
| Form | NCM (Brazil, 8 digits) | HS (international, 6 digits) | HTS (USA, 10 digits)* | CN (European Union, 8 digits)* |
|---|---|---|---|---|
| Forged bar | 7407.29.10 | 7407.29 | 7407.29.5000 | 7407 29 00 |
| Hot-rolled bar | 7407.29.10 | 7407.29 | 7407.29.5000 | 7407 29 00 |
| Plate (> 10 mm, width ≥ 600 mm) | 7409.90.00 | 7409.90 | 7409.90.1030 | 7409 90 00 |
| Seamless pipe | 7411.29.10 | 7411.29 | 7411.29.1000 | 7411 29 00 |
| Welded pipe | 7411.29.10 | 7411.29 | 7411.29.5000 | 7411 29 00 |
| Flange and fitting | 7412.20.00 | 7412.20 | 7412.20.0090 | 7412 20 00 |
Tariff class: other copper alloys (beryllium copper) (by chemical composition, under the Chapter 72 Notes and Section XV Note 5).
*: US and EU codes for reference. NCM per current legislation (General Rules of Interpretation, Notes to Chapters 72, 74 and 75 and Section XV Note 5). Confirm the final code with your customs broker according to the item size and finish. HS = first 6 digits of the NCM.
Chemical composition (%)
ASTM B441 (UNS C17510)
| Element | Range (%) |
|---|---|
| Ni | 1.4 – 2.2 |
| Be | 0.2 – 0.6 |
| Co | ≤ 0.3 |
| Fe | ≤ 0.10 |
| Al | ≤ 0.20 |
| Si | ≤ 0.20 |
| Cu | balance (Cu + named elements ≥ 99.5) |
Mechanical properties
typical, bar (CDA)
| Property | Value |
|---|---|
| Solution treated (TB00): tensile strength | ≈ 310 MPa |
| Aged (TF00): tensile strength | ≈ 760 MPa |
| Aged (TF00): yield strength (0.5%) | ≈ 620 MPa |
| Aged (TF00): elongation | ≈ 18% |
| Cold worked and aged (TH04): tensile strength | ≈ 795 MPa |
| Hardness, aged (TF00 / TH04) | ≈ 96 – 98 HRB |
Typical physical properties
| Property | Value |
|---|---|
| Density | 8.77 g/cm³ |
| Melting range | 1,029 – 1,068 °C |
| Modulus of elasticity | 132 GPa |
| Electrical conductivity (aged) | ≈ 45 – 48% IACS |
| Thermal conductivity (20 °C) | ≈ 208 W/m·K |
| Thermal expansion (20–200 °C) | 17.6 µm/m·K |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | Keeps hardness up to ≈ 300 – 400 °C in intermittent service, as in welding electrodes*; in continuous use under load, consider ≈ 250 °C*. |
| Heat treatment | Solution treatment at ≈ 845 – 925 °C with water quench. Precipitation hardening at ≈ 455 – 480 °C for ≈ 3 h, air cooling*. Hot working between ≈ 650 and 955 °C. |
| Welding | Good brazing and soft soldering. Fusion welding possible (TIG/MIG), with loss of hardness in the heat-affected zone. Oxyacetylene welding not recommended. Caution: dry machining, grinding and sanding generate beryllium-containing dust; work with coolant and local exhaust. |
| Machining | Machining similar to high-strength copper; best in the aged condition. Sharp tool, positive rake and coolant. Caution: dry machining, grinding and sanding generate beryllium-containing dust; work with coolant and local exhaust. |
Typical applications
- Electrodes, tips and electrode holders for resistance welding (RWMA Class 3)
- Seam and butt welding wheels and dies
- Injection mold inserts and cores needing fast heat transfer
- High-current electrical connectors and contacts
- Pressure and heat components in power equipment
Alternatives: C17200 when strength is the priority; chromium-zirconium copper C18150 when even higher conductivity (≈ 80% IACS) with lower hardness is needed; chromium copper C18200 as a more economical option for electrodes.
Frequently asked questions
What is the chemical composition of Low-beryllium copper C17510?
Per ASTM B441 (UNS C17510): Ni 1.4 – 2.2; Be 0.2 – 0.6; Co ≤ 0.3; Fe ≤ 0.10; Al ≤ 0.20; Si ≤ 0.20.
Which standards cover Low-beryllium copper C17510?
Bar: ASTM B441. Plate: ASTM B534 (plate, strip and rolled bar). Forging: ASTM B870 (forgings and extrusions). Tube: ASTM B937 (seamless), B944 (welded).
Up to what temperature can Low-beryllium copper C17510 be used?
Keeps hardness up to ≈ 300 – 400 °C in intermittent service, as in welding electrodes*; in continuous use under load, consider ≈ 250 °C*.
Which materials can replace Low-beryllium copper C17510?
C17200 when strength is the priority; chromium-zirconium copper C18150 when even higher conductivity (≈ 80% IACS) with lower hardness is needed; chromium copper C18200 as a more economical option for electrodes.
