CW617N Extruded Brass vs Lead-Free ECO Brass Alloys in Lock Cylinders
Engineering Overview: Metallurgical evaluation of CW617N leaded brass versus lead-free eco brass alloys (CW724R) for architectural lock cylinders adhering to RoHS/REACH.
Technical & Engineering Specifications
| Compliance | RoHS, REACH, California Prop 65 Compliant |
|---|---|
| Alloy Comparison | CW617N (Leaded) vs CW724R (Lead-Free Eco Brass) |
| Corrosion Rating | ISO 6509 Dezincification Resistant |
| Tensile Strength | 480 MPa (CW617N) vs 620 MPa (CW724R) |
| Machinability Index | 95% (CW617N) vs 65% (CW724R) |
Environmental Compliance & Metallurgy
Global environmental regulations (RoHS, REACH, and US Safe Drinking Water standards) increasingly restrict lead content. Lock manufacturers are evaluating Lead-Free Eco Brass (e.g. CW724R / CuZn21Si3P) as an alternative to standard CW617N (CuZn40Pb2).
Engineering & Machining Comparison
- CW617N (Leaded Brass): Contains 1.6%–2.5% lead, enabling 95% free-machining index, clean chip breaking, and high internal chamber concentricity.
- CW724R (Silicon Eco Brass): Replaces lead with silicon and phosphorus. It delivers higher tensile strength ($>600 ext{ MPa}$) and excellent dezincification resistance, but requires specialized carbide tooling to manage continuous stringy chips.
Summary
CW724R represents the future of green architectural hardware, while CW617N remains the global benchmark for high-speed precision pin broaching.
Frequently Asked Engineering & Selection Questions
Q1: What is the advantage of lead-free eco brass in lock cylinders?
It complies with strict international environmental regulations (RoHS/REACH) while providing higher tensile strength and corrosion resistance.