C11000 ETP Copper: Electrolytic Tough Pitch for Electrical Use vs C36000 Free-Cutting Brass: The Machinability Standard
Side-by-side engineering comparison of C11000 ETP Copper: Electrolytic Tough Pitch for Electrical Use (ASTM B152/B187) and C36000 Free-Cutting Brass: The Machinability Standard (ASTM B16/B116). Compare mechanical properties, chemical composition, density, yield strength, international equivalents, and typical applications to select the right material for your project.
Quick Verdict
Choose C11000 ETP copper when maximum electrical or thermal conductivity is the primary requirement — bus bars, wiring, heat exchangers, and grounding systems. Choose C36000 free-cutting brass when you need machinability, strength, and cost-effectiveness for mechanical components — screw-machine parts, fittings, valve stems, and hardware....
Maximum electrical and thermal conductivity
Machinability, strength, and cost for mechanical components
Quick Comparison
| Property | C11000 ETP Copper: Electr | C36000 Free-Cutting Brass |
|---|---|---|
| Standard | ASTM B152/B187 | ASTM B16/B116 |
| Category | Copper Alloy | Brass & Bronze |
| Density | 8.94 g/cm³ | 8.50 g/cm³ |
| Yield Strength | 69 MPa (10 ksi) annealed; 310 MPa (45 ksi) hard | 124 MPa (18 ksi) annealed; 310 MPa (45 ksi) hard |
| Tensile Strength | 220 MPa (32 ksi) annealed; 380 MPa (55 ksi) hard | 338 MPa (49 ksi) annealed; 469 MPa (68 ksi) hard |
| Key Applications | C11000 Electrolytic Tough Pitch (ETP) copper is the most common commercially pure copper grade, containing ≥99.90% Cu wi... | C36000 free-cutting brass (61.5% Cu, 35.5% Zn, 3% Pb) is the standard against which all other metals' machinability is m... |
International Equivalents
| C11000 ETP Copper: E Equivalents | C36000 Free-Cutting Equivalents |
|---|---|
| EN Cu-ETP | EN CuZn36Pb3 |
| CW004A | CW603N |
| JIS C1100 | JIS C3601 |
| T2 Copper | HPb59-1 |
| ISO Cu-ETP | ISO CuZn36Pb3 |
How to Choose
| Choose C11000 ETP Copper: Electr when... | C11000 ETP copper delivers 101% IACS conductivity—the standard for electrical bus bars and wiring. |
| Choose C36000 Free-Cutting Brass when... | C36000 free-cutting brass provides 100% machinability rating with 3× higher tensile strength, ideal for screw-machine parts and plumbing fittings. |
Decision Checklist: Which Is Right for You?
| Criterion | C11000 ETP Copper: E | C36000 Free-Cutting |
|---|---|---|
| Maximum Electrical And Thermal Conductivity | ✓ | |
| Machinability, Strength, And Cost For Mechanical Components | ✓ | |
| Higher yield strength | ✓ | |
| Conductivity — C11000 provides 101% IACS electrical conductivity vs on... | ✓ | |
| Machinability — C36000 has a 100% machinability rating (industry bench... | ✓ | |
| Strength — C36000 provides 460 MPa tensile strength vs 150 MPa for ann... | ✓ |
Selection Guide
Choose C11000 ETP copper when maximum electrical or thermal conductivity is the primary requirement — bus bars, wiring, heat exchangers, and grounding systems. Choose C36000 free-cutting brass when you need machinability, strength, and cost-effectiveness for mechanical components — screw-machine parts, fittings, valve stems, and hardware. C11000 conducts electricity 3.6× better; C36000 machines 5× faster.
Key Decision Factors
- Conductivity — C11000 provides 101% IACS electrical conductivity vs only 28% IACS for C36000; this 3.6× difference makes copper irreplaceable for electrical applications
- Machinability — C36000 has a 100% machinability rating (industry benchmark); pure copper is gummy and difficult to machine (20% rating) due to work hardening and ductility
- Strength — C36000 provides 460 MPa tensile strength vs 150 MPa for annealed C11000; brass is 3× stronger for mechanical load-bearing
- Cost — C36000 typically costs 20-30% less than C11000 per kg due to zinc being cheaper than copper; brass parts are also cheaper to machine
When to Use Each
Use C11000 ETP Copper: E for:
C11000 delivers 101% IACS conductivity — the benchmark for electrical conductivity. No brass alloy approaches this; for bus bars, switchgear, and power connectors, pure copper is mandatory.
C11000's thermal conductivity (391 W/m·K) is among the highest of any engineering metal — ideal for heat exchanger tubes, CPU heat spreaders, and solar thermal collectors.
C11000 copper conductors are required by NEC and UL 467 for electrical grounding — its conductivity and corrosion resistance in soil ensure reliable fault-current paths for decades.
Use C36000 Free-Cutting for:
C36000 has a 100% machinability rating (the industry benchmark) due to 3% lead content — it machines 5× faster than pure copper with excellent chip breakage and tool life.
C36000 provides 460 MPa tensile strength (3× copper's 150 MPa) with good corrosion resistance in freshwater — standard for faucet bodies, valve stems, and compression fittings.
C36000's zinc content (35%) is cheaper than copper, lowering material cost while the free-machining lead content reduces manufacturing cost — making it the economical choice for mass-produced brass parts.
Frequently Asked Questions
What is the main difference between C11000 ETP Copper: Electrolyti and C36000 Free-Cutting Brass: The?
C11000 ETP Copper: Electrolytic Tough Pitch for Electrical Use (ASTM B152/B187) provides 69 MPa (10 ksi) annealed; 310 MPa (45 ksi) hard yield strength at 8.94 g/cm³ density, while C36000 Free-Cutting Brass: The Machinability Standard (ASTM B16/B116) delivers 124 MPa (18 ksi) annealed; 310 MPa (45 ksi) hard at 8.50 g/cm³. The choice depends on whether your application prioritizes maximum electrical and thermal conductivity or machinability, strength, and cost for mechanical components.
Can C11000 ETP Copper: Electrolyti be substituted for C36000 Free-Cutting Brass: The?
Direct substitution is generally not recommended as these materials belong to different categories (Copper Alloy vs Brass & Bronze) with fundamentally different properties. Consult a materials engineer for application-specific guidance.
Why does C36000 brass machine so well?
C36000 contains 3% lead, which acts as an internal lubricant and chip breaker. The lead particles coat the cutting tool, reducing friction and enabling high-speed machining (3-5× faster than lead-free brass or copper). Chips break cleanly into small pieces rather than forming long, tangled strings. This is why C36000 is the industry's 100% machinability benchmark — all other copper alloys are rated relative to it.
Is C36000 brass safe for drinking water?
Concern exists due to the 3% lead content. In the US, the Reduction of Lead in Drinking Water Act (2014) limits lead in wetted surfaces of plumbing fixtures to 0.25% weighted average. C36000 exceeds this limit and cannot be used for potable water contact surfaces. Use lead-free brass grades (C27450, C69300, or C89550) for drinking water applications. C36000 is still permitted for non-wetted plumbing components like external trim and decorative hardware.
Can C11000 copper be hardened?
C11000 is a single-phase pure metal and cannot be precipitation-hardened. It can only be strengthened by cold work (work hardening) — cold-rolled C11000 reaches 265-380 MPa tensile strength in 'hard' temper. Annealing (200-400°C) restores full softness and conductivity. For higher-strength copper applications, use alloyed grades like beryllium copper (C17200, 1200 MPa) or chromium copper (C18200, 470 MPa).
Why is pure copper so expensive?
Copper prices fluctuate with global commodity markets but typically run $8-10/kg — driven by limited mine supply, energy-intensive extraction (smelting and electrorefining), and growing demand from electrification (EVs, renewable energy, grid expansion). Brass is cheaper because zinc (the primary alloying element at 35%) costs roughly $2.50-3/kg, reducing the weighted raw material cost. The price difference is more pronounced during copper supply constraints.
What is dezincification and does it affect C36000?
Dezincification is selective leaching of zinc from brass in corrosive water conditions, leaving a porous copper residue that weakens the part. C36000 (60% Cu, 35% Zn, 3% Pb) is susceptible to dezincification in warm, stagnant, or slightly acidic water. For plumbing applications prone to dezincification, specify DZR (dezincification-resistant) brass grades containing arsenic (C35330 or CW602N) per BS EN 12164/12165. C11000 copper is immune to dezincification because it contains no zinc.