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 |
| Property | Condition | Value | Unit |
|---|---|---|---|
| Tensile Strength | by temper & section | 530–700 | MPa |
| Yield Strength | by temper & section | 300–450 | MPa |
| Elongation | by temper | 15–30 | % |
| Machinability | vs C36000 = 100 | ~75–80% | — |
| Hot Forgeability | vs C37700 = 100 | ~95 | — |
| Density | — | 8.30 | g/cm³ |
| Standard | Designation |
|---|---|
| UNS / ASTM (USA) | C69300 — ASTM B371 |
| EN — equivalent | CW724R / CuZn21Si3P |
| ASTM silicon sibling | C6802 / CuZn17Si4 |
| 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.