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Brass vs Copper: Which Metal for Fittings, Valves and Electrical?
Brass vs Copper: Which Metal for Fittings, Valves and Electrical?
Brass and copper are both red metals, but they are engineered for different jobs. Copper is pure, soft and conductive — the default for electrical and thermal applications. Brass is a copper-zinc alloy, แข็งแกร่งขึ้น, harder and easier to machine — the default for fittings, valves and hardware. This guide explains when to choose which.
The Core Difference
ทองแดง (C11000 ETP) is 99.9 % pure copper. It conducts electricity at 101 % IACS and heat at 391 W/ม·เค, but it is soft (220 แรงดึง MPa) and dents easily. ทองเหลือง (C26000, C28000) เพิ่ม 30 - 40 % zinc, raising tensile strength to 330 - 450 MPa and making it machinable, but conductivity drops to 25 - 28 % ไอเอซีเอส. ในระยะสั้น: copper carries current and heat, brass carries load and threads. ดูของเรา C11000 copper plate และ C12200 copper tube.
| คุณสมบัติ | ทองแดง (C11000) | ทองเหลือง (C36000) |
|---|---|---|
| Composition | 99.9 % ลูกบาศ์ก | 60 % ลูกบาศ์ก, 39 % สังกะสี, 1 % Pb |
| Electrical conductivity | 101 % ไอเอซีเอส | 26 % ไอเอซีเอส |
| ความต้านทานแรงดึง | 220 - 360 MPa | 330 - 450 MPa |
| ความสามารถในการแปรรูป | ยากจน (gummy) | ยอดเยี่ยม (free-cutting) |
| ความต้านทานการกัดกร่อน | ยอดเยี่ยม (atmospheric) | ดี (dezincification risk) |
| การใช้งานทั่วไป | Busbars, หลอด, wire | ฟิตติ้ง, วาล์ว, ฮาร์ดแวร์ |
When to Use Which
Use copper for electrical busbars, transformer windings, grounding, water supply tube, refrigeration lines and heat exchangers. If the part carries current or heat, choose copper. Use brass for threaded fittings, valve bodies, pump components, เกียร์, bushings and decorative hardware. If the part needs to be machined to tight tolerances, hold a thread, or resist mechanical wear, choose brass. For plumbing, the tube is copper (C12200 DHP) but the fittings and valves are brass — that is the standard combination because the brass fitting is threaded and the copper tube is brazed onto it.
Common Mistakes
The most common error is using brass for electrical conductors because it looks “stronger.” Brass at 26 % conductivity runs hot and wastes energy — always use pure copper for current-carrying parts. The reverse error is using pure copper for valve bodies because it is “more corrosion resistant.” Pure copper is too soft to hold threads under pressure, and it will deform over time. The other risk with brass is dezincification: in aggressive water, the zinc leaches out, leaving porous copper that crumbles. For potable water, specify dezincification-resistant brass (DZR, C352) or use bronze instead.
