C36000 Free-Cutting Brass: Machinability Rating 100% — Precision Turned Parts Standard
ASTM B16 / AMS 4610 / EN CW603N · Published: 2026-05-31 · Updated: 2026-05-31
C36000 free-cutting brass (61.5% Cu, 35.5% Zn, 2.5-3.7% Pb) is the benchmark alloy for machinability — it defines the 100% machinability rating against which all other copper alloys (and many steels) are measured. The lead addition forms discrete...
C36000 free-cutting brass (61.5% Cu, 35.5% Zn, 2.5-3.7% Pb) is the benchmark alloy for machinability — it defines the 100% machinability rating against which all other copper alloys (and many steels) are measured. The lead addition forms discrete soft particles that act as chip-breakers and internal lubricants during machining, enabling cutting speeds up to 300 m/min with carbide tooling on automatic screw machines. C36000 produces small, easily cleared chips (Type 6 per ISO 3685 — short, comma-shaped) rather than long stringy chips that tangle around tools and workpieces. It is the standard material for high-volume precision turned parts: plumbing fittings, valve bodies, pneumatic connectors, clock and watch components, and electrical terminals.
Quick Facts
| Category | Brass & Bronze |
| Standard | ASTM B16 / AMS 4610 / EN CW603N |
| Density | 8.50 g/cm³ |
| Yield Strength | 124-310 MPa (18-45 ksi) depending on temper |
| Tensile Strength | 338-469 MPa (49-68 ksi) depending on temper |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN CuZn36Pb3 | Compare |
| JIS C3601 | Compare |
| GB HPb59-1 | Compare |
| DIN 2.0375 | Compare |
| BS CZ124 | Compare |
🧮 Material Weight Calculator
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Frequently Asked Questions
Is C36000 being phased out due to lead content?
Yes — the EU Drinking Water Directive (2020/2184) and U.S. Safe Drinking Water Act Amendments (Reduction of Lead in Drinking Water Act, 2011) effectively ban lead-containing brass (>0.25% Pb wetted surface) for potable water applications. For plumbing components, lead-free alternatives have been developed: C27451 (bismuth-replacing-lead), C69300 (silicon brass EcoBrass®), and C87850 (low-lead silicon brass). For non-potable industrial applications (pneumatic fittings, hydraulic adapters, electrical terminals), C36000 remains legal and widely used because no alternative matches its machinability and cost-effectiveness. C36000 is likely to remain available for industrial (non-water-contact) applications for decades, but its use in potable water components is now prohibited in most jurisdictions.
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu