Weight %. Silicon replaces lead: ~3% Si forms a kappa-phase that breaks chips during cutting and suppresses dezincification — no arsenic inhibitor needed.
| Element | Symbol | Min % | Max % | Typical % |
|---|---|---|---|---|
| Copper | Cu | 73.0 | 77.0 | 75.0 |
| Zinc | Zn | Balance | ~21 | |
| Silicon | Si | 2.7 | 3.4 | 3.0 |
| Phosphorus | P | 0.04 | 0.15 | 0.07 |
| Lead (max) ✓ | Pb | — | 0.09 | ≤0.05 |
Note: ASTM/UNS C69300 caps lead at ≤0.09%, while the EN twin CW724R (EN 12164) allows ≤0.10% — a genuine (small) difference between the twin standards, not an inconsistency.
| Property | Condition | Value | Unit |
|---|---|---|---|
| Tensile Strength | by temper & section | 530–700 | MPa |
| Yield Strength | by temper & section | 300–450 | MPa |
| Elongation | by temper | 10–25 | % |
| Hardness | half-hard, typ | 80–90 | HRB |
| Machinability | vs C36000 = 100 | ~80% | — |
| Hot Forgeability | vs C37700 = 100 | ~95 | — |
| Density | — | 8.30 | g/cm³ |
| Thermal Conductivity | — | ~38 | W/(m·K) |
| Melting Range | solidus–liquidus | 855–880 | °C |
| Standard | Designation |
|---|---|
| UNS / ASTM (USA) | C69300 — ASTM B371 |
| EN — equivalent | CW724R / CuZn21Si3P |
| Lead-free bismuth alt. | C6802 — bismuth brass |
| Chemical designation | CuZn21Si3P |
| Trade name | Lead-Free Silicon Brass |
C69300 is a lead-free silicon brass (CuZn21Si3P) with 73–77% copper, ~3% silicon, and lead held at or below 0.09%. The silicon kappa-phase gives it chip-breaking machinability (~75–80%), intrinsic dezincification resistance, and the highest strength of any grade in our library — the standard choice for low-lead potable-water components.
C69300 is the UNS twin of CW724R — both are CuZn21Si3P. The same bar stock typically certifies to either designation; we confirm the certificate wording your market requires at quotation.
The material meets NSF/ANSI 372 (weighted Pb ≤0.25%) and is dezincification resistant per ISO 6509-1, making it suitable for potable-water components in the US, Canada, UK and EU. Note that end-product approvals (NSF 61, WRAS, KTW, etc.) attach to the finished product and are held by the product maker — we machine components to your approved drawing.
Expect roughly 75–80% of the C36000 benchmark: slightly higher cutting forces and tool wear, but well-broken chips and excellent surface finish on sliding-head CNC machines. It is significantly harder than leaded brass, so feeds and tooling are adjusted — send your drawing for a quote within 24 hours.
Lead-free, DZR, NSF/ANSI 372 — no exemption required. ISO 9001:2015. Quote within 24 hours.
Request a QuoteComposition ranges, mechanical properties, machinability ratings and regulatory data on this page are cross-referenced against the publishers below. Tolerances and minimum values are taken from the relevant published standard at the time of writing — for procurement specification, always reference the current published edition.
Last reviewed: June 2026. EN/ISO/ASTM standards are updated periodically. This datasheet reflects the editions listed; for safety-critical or contract-critical applications, always 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 C69300 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.