COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF UNS C64200 ALUMINUM SILICON BRONZE FASTENERS
UNS C64200, commonly known as Aluminum Silicon Bronze, is a revolutionary engineering alloy designed to solve one of the greatest modern metallurgical challenges: achieving high-speed machinability without the use of toxic lead. By alloying Copper with precisely 6.3% to 7.6% Aluminum and 1.5% to 2.2% Silicon, the metal develops hard, microscopic silicide particles within its crystalline matrix. During CNC turning, these silicon particles act as natural "chip breakers," granting the alloy an outstanding 60% Machinability Rating while remaining fully lead-free.
Beyond its manufacturing advantages, C64200 is a powerhouse of physical durability. It boasts high tensile strength (up to 90,000 psi), exceptional resistance to marine corrosion, and an incredibly low coefficient of friction. Because it strictly complies with the Safe Drinking Water Act (SDWA) and global RoHS directives, C64200 is the ultimate, uncompromising choice for municipal water valve stems, high-wear marine turnbuckles, and precision electromechanical fasteners where lead contamination is strictly prohibited.
■ Product Overview & Specifications
| Material Classification | Lead-Free Free-Machining Bronze (Aluminum-Silicon) |
|---|---|
| UNS Designation | C64200 |
| Microstructure | Alpha-Beta Matrix with Hard Silicide Precipitates |
| Magnetic State | Completely Non-Magnetic |
| Density | 7.69 g/cm³ (0.278 lb/in³) |
| Size Range | Metric: M4 to M36 | Imperial: #8 to 1-1/2" |
| Primary Attribute | High Machinability (60%) combined with SDWA Lead-Free Compliance |
■ Proprietary Datasheet Download (GATED)
UNS C64200 Aluminum Silicon Bronze — Complete Technical Datasheet
Contains detailed CNC turning feed rates for lead-free tooling, official Safe Drinking Water Act compliance certificates, and dynamic friction (galling) limits for valve stem assemblies.
⬇ DOWNLOAD DATASHEET■ MTC Integration Section
In potable water and highly regulated industries, proving the absence of heavy metals is legally mandatory. Ananka ensures that every lot of C64200 bar stock is backed by stringent, third-party verified chemical traceability to guarantee its "lead-free" status.
- EN 10204 Type 3.1: Validates the critical <0.05% Lead cap, verifies the precise Aluminum and Silicon strengthening additions, and guarantees the structural integrity of the half-hard temper.
- EN 10204 Type 3.2: Available upon request for municipal wastewater facilities, naval shipyard contracts, or food-processing plant infrastructure requiring independent testing oversight.
■ Chemical Composition
C64200 achieves its unique properties without relying on toxic heavy metals. The Aluminum provides high tensile strength and oxidation resistance, while the Silicon dramatically improves fluidity during casting and forms the chip-breaking silicide particles necessary for high-speed automated machining.
| Copper (Cu) | Aluminum (Al) | Silicon (Si) | Iron (Fe) | Lead (Pb) | Zinc (Zn) |
|---|---|---|---|---|---|
| Balance (~89.0) | 6.30 – 7.60 | 1.50 – 2.20 | 0.30 Max | 0.05 Max (Lead-Free) | 0.50 Max |
■ Mechanical Properties
| Mechanical Property | Typical Limits (HR50 / Half-Hard Temper) |
|---|---|
| Tensile Strength | 75,000 - 90,000 psi (515 - 620 MPa) |
| Yield Strength | 35,000 - 45,000 psi (240 - 310 MPa) |
| Machinability Rating | 60% (Lead-Free Benchmark standard) |
| Hardness (Rockwell B) | 75 - 85 HRB |
■ Equivalent Grades & Designations
| Standard / System | Designation |
|---|---|
| ASTM Specifications | ASTM B150 (Rod, Bar, and Shapes), ASTM F467/F468 |
| Common Trade Names | Aluminum Silicon Bronze, Alloy 642, Lead-Free Bronze |
| European Equivalent | EN CW301G / CuAl7Si2 (Approximate) |
| Military / Marine Std | MIL-B-46118 |
■ Applications & Industries
- Potable Water & Plumbing: Threaded valve stems, water meter fasteners, and pump hardware legally required to be 100% lead-free under the Safe Drinking Water Act.
- Marine & Naval Architecture: High-strength, non-magnetic deck hardware, turnbuckles, and propeller retaining nuts that require superior anti-galling properties in saltwater.
- Aerospace & Heavy Electromechanical: Precision CNC-turned gears, cams, and high-wear structural fasteners that demand high strength but cannot suffer from the brittle fracturing associated with leaded brasses.
■ Compatible Fastener Assemblies
| Mating Bolts/Studs/Valve Stems | Internal Threads (Nuts) | Washers |
|---|---|---|
| C64200 CNC Turned Screws & Bolts | C64200 Custom Machined Nuts | C64200 or Silicon Bronze Flat Washers |
■ Torque & Installation Guidelines
C64200 is specifically praised for its anti-galling properties. The unique Aluminum-Silicon matrix creates a naturally lubricious surface that severely reduces friction when tightening. While it resists "cold welding" far better than pure Silicon Bronze or 316 Stainless, standard anti-seize is still recommended for large-diameter marine assemblies.
| Nominal Diameter | Threads Per Inch (UNC) | Max Target Torque (in-lbs) | Max Target Torque (ft-lbs) |
|---|---|---|---|
| 1/4" | 20 | 75 - 85 | ~ 6.5 |
| 3/8" | 16 | 210 - 230 | ~ 18 |
| 1/2" | 13 | 450 - 500 | ~ 40 |
| 3/4" | 10 | 1450 - 1550 | ~ 125 |
■ Frequently Asked Questions
1. How does it achieve "Free-Machining" without using Lead?
In traditional alloys like C36000 or C54400, microscopic drops of Lead act as chip breakers to stop the metal from gumming up cutting tools. Because Lead is toxic, C64200 uses an entirely different mechanism. The Silicon in the alloy reacts to form hard, microscopic "silicide" particles. When a cutting tool hits these hard particles, the metal chip cleanly snaps off. This allows manufacturers to run CNC machines at very high speeds completely lead-free.
2. Is C64200 safe for commercial drinking water systems?
Absolutely. It is the premier alloy for this exact purpose. Due to modern revisions of the Safe Drinking Water Act (SDWA) and the European RoHS directives, heavily leaded brasses and bronzes have been banned from components touching potable water. C64200 caps lead at an ultra-low 0.05% maximum, making it fully compliant and safe for municipal water grids.
3. Does Aluminum Silicon Bronze suffer from "Dezincification"?
No. Dezincification is a specific type of corrosion that destroys alloys containing high amounts of Zinc (like standard 60/40 brass) when exposed to seawater. C64200 contains a maximum of 0.50% Zinc, relying instead on Aluminum and Silicon for its structural base. Because of this, it is entirely immune to dezincification, making it phenomenally stable in ocean water.
