Lead-Free Eco Brass CW724R (CuZn21Si3P) Broaching Mechanics and Tool Wear
Engineering Overview: Machinability guide on precision CNC broaching and rotary transfer drilling of CW724R silicon eco brass lock cylinder bodies.
Technical & Engineering Specifications
| Standard | RoHS / REACH / California AB 1953 |
|---|---|
| Alloy Grade | Lead-Free Eco Brass CW724R (CuZn21Si3P) |
| CNC Tooling | Coated Solid Carbide Tools with High-Pressure Coolant |
| Lead Content | < 0.05% Pb (100% Compliant) |
| Tensile Strength | > 600 MPa Ultra-High Yield |
Eco Brass Machinability Science
To comply with strict California Prop 65 and European drinking water lead bans, lock foundries specify CW724R (CuZn21Si3P) silicon brass.
Tooling & Broaching Adjustments
- Silicon Strengthening: High silicon content (2.7%–3.5%) forms hard kappa-phase micro-particles that increase abrasive cutter wear by 40%.
- Tooling Solution: Solid sub-micron carbide broaching bars with TiAlN PVD coatings and high-pressure oil coolant maintain $\pm 0.005\text{ mm}$ pin chamber concentricity.
Frequently Asked Engineering & Selection Questions
Q1: What tooling is required to machine lead-free eco brass cylinders?
Coated solid sub-micron carbide broaches and drills with high-pressure coolant to manage the abrasive silicon particles in the alloy.