In the brass alloy family, C28000 (Muntz Metal) and C36000 (Free-Cutting Brass) represent a fundamental fork in the road. Their selection defines the core manufacturing process for a part. C28000 is the champion of cold workability and strength, while C36000 is the undisputed king of high-speed machining. Understanding their stark differences is crucial for optimizing cost, performance, and production efficiency.
Chemical Composition
C28000 Brass (60/40 Brass): Contains 60.0-63.0% Copper and ≤ 0.30% Lead (typically <0.07%). It is classified as a low-lead or "lead-free" brass. The balance is zinc. Its structure is alpha-beta (α+β).
C36000 Brass (Free-Cutting Brass): Contains 60.0-63.5% Copper and a deliberately high 2.5-3.7% Lead. The lead exists as dispersed particles within the microstructure. The balance is zinc. Its structure is also alpha-beta but modified by lead.
Mechanical & Physical Properties
| Property | C28000 Brass (Low-Lead) | C36000 Brass (High-Lead) | Consequence for Design |
|---|---|---|---|
| Primary Attribute | Excellent Cold Workability | Exceptional Machinability | Defines the feasible fabrication method. |
| Machinability Rating | Fair (~40% of C36000) | Excellent (100% benchmark) | C36000 enables faster speeds, lower power, longer tool life, and better finish. |
| Chip Formation | Long, stringy, tough chips. | Short, broken, easily cleared chips. | C36000 is essential for automated, high-volume CNC machining. |
| Tensile Strength | Higher (Annealed: ≥ 370 MPa) | Lower (Annealed: ~ 310 MPa) | C28000 provides greater mechanical strength in the final part. |
| Ductility / Elongation | Good (~20% in annealed) | Very Poor (~15% in annealed) | C28000 can be severely bent, stamped, and drawn; C36000 is brittle and will crack. |
| Hot Workability | Excellent | Not Recommended | C28000 can be forged; C36000's lead causes "hot shortness" and melting. |
| Cold Workability (Bending, Stamping) | Excellent | Very Poor | C36000 is unsuitable for any significant post-machining forming. |
Performance & Regulatory Considerations
Corrosion & Environmental Resistance
Both offer similar baseline corrosion resistance in atmospheric conditions. However, C28000 often has an edge in certain aqueous environments due to its more homogeneous microstructure. The lead particles in C36000 can sometimes create galvanic sites.
The most significant difference is regulatory. C28000, with its very low lead content, is approved for use in potable water systems (subject to local standards like NSF/ANSI 61) and is compliant with strict regulations like the U.S. Safe Drinking Water Act and EU RoHS/REACH for many applications. C36000 is almost universally prohibited for any potable water contact and faces restrictions in consumer goods and electronics due to its high lead content.
Joining and Finishing
Welding/Brazing: C28000 can be welded and brazed with standard techniques for copper alloys. C36000 is very difficult to weld or brace; the lead liquifies and causes cracks, porosity, and toxic fumes.
Plating/Finishing: Both accept plating well, but the porous surface of machined C36000 sometimes requires special sealing processes to prevent plating solution entrapment.
Application Domains
C28000 Brass is the "Fabricator's Alloy":
Architectural & Decorative Hardware: Hinges, locks, door handles, decorative trim that require stamping and bending.
Heat Exchanger Components: Fins, plates, and tubes that are formed.
Electrical Components: Connectors, terminals, and spring contacts that are stamped and formed.
Plumbing Fittings: Where lead content regulations allow (using low-lead C28000).
Fasteners & General Hardware.
C36000 Brass is the "Machinist's Alloy":
High-Volume Precision Parts: Plumbing valves, pipe fittings, gear blanks, watch components, lock mechanisms.
Electrical Fittings: Nuts, connectors, terminals that are entirely machined.
Automotive Components: Fuel system parts, sensor housings.
Any part where the final shape is achieved primarily through material removal (turning, milling, drilling, tapping) on automated screw machines or CNCs.
Cost & Production Economics
Material Cost: C36000 often carries a small premium over C28000 due to the added lead and its status as a specialty machining feedstock.
Total Part Cost: This is where the decision is made. For a complex part:
If it can be stamped or formed from sheet/coil, using C28000 will be dramatically cheaper due to high-speed, low-waste production.
If the part requires complex 3D shapes, tight threads, or bored holes, machining it from C36000 rod will be far more economical than machining C28000. The savings in machining time, tool wear, and power consumption vastly outweigh the material premium.
Our product range
1. Pure Copper (Sheet, Tube, Wire)
Primary Grades: T1 (C11000), T2 (C10100). We prioritize C11000 (T1) for its excellent conductivity.
Standards: ASTM B152 (Sheet), ASTM B75/B88 (Tube), ASTM B1/B3 (Wire), EN, JIS, GB/T.
Typical Sizes:
Tube: OD 6mm – 200mm.
Sheet: Thickness 0.5mm – 50mm.
Wire: Diameter 1.0mm – 10mm.
2. Phosphorus Deoxidized Copper (Tube, Sheet)
Primary Grades: TP1 (C12000 / CW023A), TP2 (C12200). Ideal for welding and plumbing.
Standards: ASTM B188, ASTM B75/B88, EN 12451, JIS H3300.
Typical Sizes:
Tube: OD 8mm – 150mm.
Sheet: Thickness 1.0mm – 30mm.
3. Brass (Strip & Coil)
Primary Grades: H96, H68, H62 (CuZn37 / C28000). We strongly recommend H62 for its excellent balance of strength and machinability.
Standards: ASTM B36, ASTM B134, EN 1652, JIS H3100.
Typical Sizes:
Strip/Coil: Thickness 0.1mm – 3.0mm, Width up to 600mm.
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Our factory
Our facility is equipped with industry-advanced continuous casting and rolling production lines, precision rolling mills, multi-pass drawing units, and automated forming equipment, enabling efficient and stable transformation from copper rods to finished products. Our core machinery allows us to flexibly manufacture a full range of grades-including pure copper (e.g., C11000/T1), phosphorus deoxidized copper (e.g., C12200/TP2), and brass (e.g., H62)-in the form of sheets, tubes, rods, strips, and wires. We also provide tailored processing services such as cutting, slitting, and precision finishing.
