Brass is not a single material but a family of copper-zinc alloys, each with distinct properties suited to different applications. For B2B buyers specifying CNC machined brass components, understanding these alloy differences is crucial for making informed procurement decisions.
C360 Free-Cutting Brass (The Industry Standard)
C360 brass, also known as free-cutting brass, dominates the CNC machining landscape with a 100% machinability rating—the benchmark against which all other materials are measured. Its composition (61.5% copper, 35.4% zinc, 3.1% lead) creates an optimal balance of strength, corrosion resistance, and exceptional chip formation during machining [2].
The lead content in C360 is the key to its superior machinability. Lead acts as a chip breaker, allowing for higher cutting speeds, reduced tool wear, and smoother surface finishes. This translates to 5x faster machining cycles compared to steel and significantly lower per-unit production costs for high-volume orders.
C260 Cartridge Brass (70/30 Brass)
With 70% copper and 30% zinc, C260 offers excellent cold working properties and superior corrosion resistance compared to C360. However, its machinability rating drops to approximately 30%, making it less economical for complex CNC operations. C260 is preferred for applications requiring extensive forming after machining, such as deep-drawn components or parts requiring significant bending.
C464 Naval Brass (Marine-Grade)
C464 contains 60% copper, 39.2% zinc, and 0.8% tin. The tin addition provides exceptional corrosion resistance in saltwater environments, making this alloy the standard for marine hardware, offshore oil & gas components, and coastal infrastructure applications. Machinability is moderate (around 60% of C360), but the corrosion resistance justifies the premium for marine applications.
C385 Architectural Bronze
Despite its name, C385 is actually a brass alloy (57% copper, 40% zinc, 3% lead). It's prized for decorative applications—door hardware, architectural trim, lighting fixtures—where aesthetic appeal matters as much as mechanical properties. The alloy takes polish exceptionally well and develops an attractive patina over time.
Brass Alloy Comparison: Properties, Machinability & Typical Applications
| Alloy Designation | Composition | Machinability Rating | Key Properties | Primary Applications | Cost Relative to C360 |
|---|
| C360 (Free-Cutting) | 61.5% Cu, 35.4% Zn, 3.1% Pb | 100% (Benchmark) | Excellent machinability, good strength, fair corrosion resistance | Electrical connectors, terminal blocks, valve components, gears, fasteners | 1.0x (Baseline) |
| C260 (Cartridge) | 70% Cu, 30% Zn | 30% | Excellent cold working, superior corrosion resistance, lower machinability | Ammunition casings, deep-drawn parts, springs, corrosion-resistant fittings | 1.2-1.5x |
| C464 (Naval) | 60% Cu, 39.2% Zn, 0.8% Sn | 60% | Exceptional marine corrosion resistance, moderate machinability | Marine hardware, offshore components, pump parts, propeller shafts | 1.3-1.6x |
| C385 (Architectural) | 57% Cu, 40% Zn, 3% Pb | 90% | Excellent polishability, attractive patina, good machinability | Door hardware, architectural trim, lighting fixtures, decorative elements | 1.1-1.4x |
| C482/C485 (Leaded Naval) | 59% Cu, 39% Zn, 1-2% Pb, 0.8% Sn | 80% | Marine corrosion resistance + improved machinability | Marine valves, fittings, pump components requiring both properties | 1.4-1.7x |
Source: PTSMake Brass CNC Machining Guide, 3ERP Brass Grades Reference. Cost multiples vary by order volume and geographic region. For B2B buyers on Alibaba.com, C360 offers the best balance of performance and cost for most applications
[2].
Material Selection Decision Framework
When specifying brass alloys for CNC machined components, B2B buyers should consider:
Machining Complexity: Complex geometries with tight tolerances favor C360 due to its superior chip formation and dimensional stability during cutting.
Environmental Exposure: Marine, chemical, or high-humidity environments warrant C464 naval brass despite higher costs. The corrosion resistance prevents premature failure and reduces warranty claims.
Post-Machining Operations: If parts require extensive bending, forming, or cold working after CNC machining, C260's superior ductility becomes valuable.
Aesthetic Requirements: Decorative applications where surface finish and long-term appearance matter benefit from C385's polishability and patina development.
Regulatory Compliance: Lead content restrictions (such as EU RoHS for certain applications) may require lead-free alternatives like C377 or C385, though machinability will be reduced.
For merchants selling on Alibaba.com, offering multiple alloy options with clear technical specifications demonstrates expertise and helps buyers make confident decisions. Product listings should explicitly state alloy designation, composition range, and relevant certifications.
