Mass %, Copper Development Association: copper plus the named elements at least 99.7 %. Typical column: nominal analysis (62.5–63 Cu – 1.0 Si – 0.07 P).
| Element | Symbol | Min % | Max % | Typical % |
|---|---|---|---|---|
| Copper | Cu | 60.5 | 65.0 | 62.5–63 |
| Silicon | Si | 0.7 | 1.3 | 1.0 |
| Phosphorus | P | 0.01 | 0.10 | 0.07 |
| Lead | Pb | — | 0.10 | <0.1 |
| Tin | Sn | — | 0.30 | <0.2 |
| Iron | Fe | — | 0.20 | — |
| Nickel | Ni | — | 0.20 | — |
| Manganese | Mn | — | 0.20 | — |
| Antimony | Sb | — | 0.10 | — |
| Bismuth | Bi | — | 0.05 | — |
| Selenium | Se | — | 0.05 | — |
| Cadmium | Cd | — | 0.0075 | <0.0075 |
| Zinc | Zn | Balance | rem. | |
Physical properties are typical values; a range shows the spread of published data (reference: Copper Development Association). Strength depends on the supply condition.
| Property | Condition | Value | Unit |
|---|---|---|---|
| Density | at 20 °C | 8.24–8.3 | g/cm³ |
| Melting Range | solidus–liquidus | 865–880 | °C |
| Electrical Conductivity | at 20 °C | 16–16.5 | %IACS |
| Thermal Conductivity | at 20 °C | 73–74 | W/(m·K) |
| Thermal Expansion | 20–300 °C | 18–19 | ×10⁻⁶/K |
| Tensile Strength | as hot extruded, M30: minimum / typical | ≥421 / ~517 | MPa |
| 0.2 % Yield / Elongation | as hot extruded, M30 — typical | ~234 / ~10 | MPa / % |
| Hardness | as hot extruded, M30 — typical | ~75 | HRB |
| Tensile / Yield / Elongation | bar Ø20 mm, longitudinal — typical | 625 / 470 / 20 | MPa / MPa / % |
| Tensile Strength | supply conditions R450 / R480 / R540 (minimum) | ≥450 / ≥480 / ≥540 | N/mm² (MPa) |
| Machinability | CDA rating, C36000 = 100 | 80 | index |
Fabrication ratings: the Copper Development Association rating for C68370 and typical data for CW726R rod.
| Process | CDA (C68370) | CW726R — typical |
|---|---|---|
| Machinability | 80 (C36000 = 100) | 90 % (CuZn39Pb3 = 100 %); rated good |
| Hot working | Excellent — forgeability rating 120 (C37700 = 100) | Excellent — 550–650 °C; forgeability excellent (580–650 °C) |
| Cold working | Poor | Fair |
| Soldering | Excellent | Soft soldering good |
| Brazing | Good | Hard soldering good |
| Welding | Oxyacetylene, gas-shielded arc, coated metal arc, spot, seam and butt welding good | Resistance butt welding and inert-gas arc welding fair; gas welding poor |
| Annealing / stress relief | — | Soft annealing 450–500 °C (2–3 h); stress relief 200–300 °C (1–3 h) |
| Standard | Designation |
|---|---|
| UNS (USA) | C68370 — Copper Development Association (no ASTM specification listed) |
| EN (Europe) | CW726R / CuZn36Si1P — added to EN 12164:2024 (rod for free machining) and EN 12165:2024 (forging stock) |
| JIS (Japan) | none listed |
| Related lead-free grade | C69300 / CW724R — silicon brass with 73–77 % copper (CW724R: 75–77 %) |
C68370 is a lead-free brass that contains silicon instead of lead: 60.5–65.0 % copper, 0.7–1.3 % silicon, 0.01–0.10 % phosphorus and at most 0.10 % lead, balance zinc, with limits for tin, iron, nickel, manganese, antimony, bismuth, selenium and cadmium (Copper Development Association). In Europe it carries the number CW726R.
CW726R (CuZn36Si1P) is the European number of the same lead-free brass. It was added to the European product standards in their 2024 editions: EN 12164:2024 for free-machining rod and EN 12165:2024 for forging stock. EN 12164 notes a patent claim on the alloy.
Both are lead-free brasses with silicon, but C69300 / CW724R contains 73–77 % copper (CW724R: 75–77 %) and about 3 % silicon and is dezincification-resistant, while C68370 has 60.5–65.0 % copper and about 1 % silicon — close to ordinary brass. Its corrosion resistance is comparable with ordinary leaded brass, and it is not a dezincification-resistant grade. The machinability ratings are 80 for C68370 and 85 for C69300 (C36000 = 100).
Yes. Lead is limited to 0.10 %, within the 0.1 % RoHS threshold for lead in a homogeneous material, so no exemption is needed and the alloy counts as lead-free under RoHS and ELV. The same limit keeps the material within NSF/ANSI 372 (0.25 % weighted lead on wetted surfaces). For drinking water in the EU, the European positive list (Decision (EU) 2024/367) names CW724R, not CW726R.
Its machinability rating is 80 (C36000 = 100). The chips break at the β phase instead of at lead particles; where chips do not break, a higher feed and a lower cutting speed than for leaded brass help.
Yes — turned and milled to your drawing in Jamnagar. Whether bar certified to C68370 or CW726R is available for your quantity is confirmed at quotation; every shipment carries an EN 10204 3.1 mill certificate. Series lead time is 3–5 weeks from the approved drawing.
UNS C68370, or CW726R / CuZn36Si1P with the EN standard and edition your supplier certifies to.Primary source: Copper Development Association — UNS C68370.
Lead-free brass parts turned, milled and inspected in Jamnagar. ISO 9001:2015. Quote within 24 hours.
Request a QuoteComposition limits are those of the UNS registration (Copper Development Association); in Europe the alloy is specified as CW726R in EN 12164:2024. For procurement specification, always reference the current published edition of the standard.
Last reviewed: September 2026. UNS limits from the Copper Development Association; typical values are not specification limits. For safety-critical or contract-critical applications, verify against the current published edition of the standard. For project-specific deviations or supplier-specific composition windows, request a Type 3.1 mill certificate (EN 10204) with your order.
Brassland machines C68370 into brass turned parts and CNC machined components to your drawing in Jamnagar, India, including precision turned brass components on 28+ Swiss-type lathes, with an EN 10204 3.1 certificate on every shipment.