Copper, Brass and Bronze Alloys

Copper alloys are chosen for what steel and aluminum cannot do: carry current and heat (pure copper is second only to silver), run against steel without galling (bronze bearings), machine faster than any other metal (free-cutting brass), resist seawater biofouling, and spark less. Alloying with zinc gives brass, with tin, aluminum or silicon gives the bronzes, and a little beryllium or chromium gives spring and electrode alloys with the strength of steel. Density is heavy — 10 % more than steel — and raw copper is priced like a commodity, so the family is used where its properties, not its bulk, do the work.

Copper alloys by group

Pure & oxygen-free copper≥ 99.3 % Cu · C110, C101, C102, C12210132 – 1,070Bus bars, windings, heat sinks, vacuum and RF hardware — 100 % IACS conductivity; soft, gummy to machine, excellent to form and braze.

High-copper alloys≥ 96 % Cu + Be, Cr, Zr, Te · C172, C182, C145, CuCrZr3180 – 1,000Springs, connectors, resistance-welding electrodes, mold inserts, non-sparking tools — steel-like strength while keeping 20–85 % of copper's conductivity.

C16200
C16500
C17000
C17200
C17300
C17410
C17450
C17460
C17465
C17500
C17510
C18100
C18400
C18600
C18700
C18900
C18980
C19000
C19010
C19020
C19025
C19100
C19200
C19210
C19400
C19410
C19500
C19700
C19800
CuCrZr
CuNi2SiCr

BrassCu + 5–40 % Zn (± Pb, Sn) · C260, C360, C464, C3856675 – 415Fittings, valve bodies, gears, fasteners, decorative and musical hardware — the most machinable metal (C360) and the most formable copper alloy (C260 cartridge brass).

Phosphor bronzeCu + 1–10 % Sn, P · C510, C519, C521, C54414140 – 585Springs, electrical contacts, bellows, fasteners, bearing strip — high fatigue strength and low friction; C544 (leaded) for machined bushings.

Aluminum bronzeCu + 5–11 % Al, Fe, Ni · C630, C642, C954, C95529165 – 855Marine shafts, propellers, pump impellers, heavy-duty bearings, forming dies — the strongest wrought bronzes, excellent in seawater and against galling.

Silicon bronze & copper-nickelCu + Si, Mn · C655 · Cu + 10–30 % Ni · C706, C71568105 – 1,000Marine fasteners, architectural welds, hydraulic lines, seawater piping and condenser tubes — weldable, non-biofouling, resistant to salt and stress corrosion.

Cast bronzes & brassesSn-Pb bearing bronze, red brass, Mn bronze · C932, C936, C836, C86315862 – 1,035Bushings, thrust washers, worm gears, pump and valve bodies — cast to near-net shape; C932 (SAE 660) is the universal bearing bronze.

Choose a copper alloy for

Bus bars, terminals, heat sinks and welding electrodes (pure and high-copper grades); fittings, valves, gears and decorative hardware in volume (brass, the fastest-machining metal there is); bushings, wear plates and worm gears running against steel (tin and aluminum bronze); springs and connectors that flex millions of times (phosphor bronze, beryllium copper); and pump, propeller and seawater hardware (naval brass, aluminum bronze, silicon bronze).

Look elsewhere when

Weight matters (copper alloys are three times as dense as aluminum), strength per dollar matters (steel), the part sees ammonia, sulfides or acidic condensate (brass dezincifies and stress-cracks), the temperature exceeds ~250 °C under load, or the environment forbids copper ions (some food, potable-water and electronics-clean-room specs). Lead-free requirements also rule out the classic C360 free-cutting brass — ask for C693 / ECO BRASS or C27450 instead.

Yield strength against electrical conductivity, every copper alloy grade

No materials in view have both of these properties.

Loading the library…

Copper Alloy by application

Carry current or heat: C110 for bus bar and terminals; C101 / C102 oxygen-free for vacuum, cryogenic and RF parts; C182 (Cu-Cr) and C175 where the conductor also needs strength or runs hot.
Fast machined parts in volume: C360 is the 100 % machinability reference; C353 for stampings that are also machined; C544 when the part is a bushing; C145 (tellurium copper) for machinable conductors.
Bushings, bearings and worm gears: C932 (SAE 660) against hardened steel shafts; C936 for higher loads with poor lubrication; C954 aluminum bronze for heavy, slow, shock-loaded bearings and forming dies.
Springs and connectors: C510 for most stamped springs and contacts; C521 / C524 for higher stress; C172 beryllium copper when the spring must be small, hot or cycle indefinitely.
Seawater and marine hardware: C464 naval brass for shafts and fittings; C630 / C955 for propellers, pump parts and shafts under load; C655 for fasteners and welded assemblies.
High strength, non-sparking, anti-galling: C630 and C642 for hardware that must not gall or spark; C863 manganese bronze for the heaviest cast gears and bearings; C172 for the strongest springs and tooling.
Deep-drawn and formed parts: C260 (70/30 cartridge brass) is the deep-drawing standard; C122 DHP copper for tube and spun parts; C220 commercial bronze for coinage-color trim.
Architectural and decorative: C385 extrusions for handrails and storefronts; cast red brass for hardware and plumbing; patinas and lacquer control the finish.

FabAgentAI

AI suggestions — verify with an engineer before ordering. Estimates are indicative; the quote page prices your exact geometry.

Manufacturing notes

CNC machining

Feed per tooth mm/tooth

Ø6 mm · 3-flute carbide end mill

Distance the cutter advances between successive teeth (chip load). Published per material; independent of tool diameter.

n = 1,000 v_c / (πD)v_f = f_z × z × nD = 6 mm · z = 3 flutes · diagram not to scale

Brass C360 cuts faster than any other metal and holds tight tolerances with no burr — ideal for screw-machine and Swiss work. Bronzes are slower but still easy. Pure copper is the difficult one: gummy, smears, and needs sharp positive tools and high speed; use C145 tellurium copper if a conductor must be machined in volume. Beryllium copper requires dust control.

Sheet metal and stamping: C260 cartridge brass and C110 copper deep-draw and form superbly; phosphor bronze C510 is the spring-stamping standard. Bend leaded brass only at large radii — it cracks. Annealed tempers form, hard tempers spring.
Joining: Copper alloys braze and solder better than any other family — silver brazing is the default joint. TIG welding works for silicon bronze, aluminum bronze and copper-nickel; brass welds poorly (zinc fume), leaded alloys not at all. Pure copper needs very high heat input because it conducts the heat away.
Heat treatment: Most copper alloys strengthen only by cold work — the H temper on brass and bronze is a rolling temper, not a hardness after heat treatment. Beryllium copper (C172, C175) and chromium copper (C182, CuCrZr) are the exceptions: machine in the soft condition, then age at 315–480 °C.
Finishing: Bright dip, tin or silver plate (for contacts), nickel or chrome (for wear and color), lacquer or patina for decorative work. Passivation with benzotriazole slows tarnish. Copper alloys are not anodized; brass parts for potable water may need lead-free grades or a lead-leach treatment.

Most-quoted copper alloy grades

Grade	Group	Yield, MPa	Tensile, MPa	Density, g/cm³	Machinability	Weldability	Best for
C11000	Pure & oxygen-free copper	69	221	8.94	Poor	Fair	Bus bars, conductors, heat sinks
C36000	Brass	310	385	8.5	Excellent	Poor	High-volume machined fittings
C26000	Brass	105	325	8.53	Poor	Fair	Deep-drawn and formed parts
C51000	Phosphor bronze	140	340	8.86	Poor	Fair	Springs and contacts
C17200	High-copper alloys	260	490	8.26	Fair	Fair	Highest-strength springs, tooling
C63000	Aluminum bronze	415	760	7.58	Poor	Good	Marine shafts, anti-galling wear parts
C93200	Cast bronzes & brasses	125	240	8.93	Very good	Poor	Bushings and bearings
C46400	Brass	172	380	8.41	Fair	Fair	Seawater fittings and shafts
C35300	Brass	345	420	8.47	Very good	Poor	Standard screw-machine brass
C48500	Brass	280	470	8.41	Very good	Poor	High-strength marine brass

Finishes for copper alloy

All 111 finishes

76 of our 111 surface finishes take copper alloy: 26 recommended outright, 28 with process care, 22 in limited cases. Each finish opens to its datasheet — thickness, hardness, salt-spray hours, spec codes and the copper alloy-specific notes — and the configurator prices it on the grade you pick.

Finish	Group	On copper alloy	Thickness, µm	Hardness, HV	Salt spray, h	Cost
Electropolishing	Anodizing, conversion & passivation	Limited	removes 5–25	—	—	$$$
Copper Plating	Plating & metallizing	Yes	5–30	50–250	—	$$
Decorative Nickel-Chrome Plating	Plating & metallizing	Yes	0.3–1	700–1,000	96–500	$$$
Electroless Nickel Plating	Plating & metallizing	Yes	5–75	450–1,000	100–1,000	$$$
Cerakote	Paint, powder & polymer coatings	With care	20–30	—	500–1,000	$$$
Conductive Coating	Paint, powder & polymer coatings	With care	15–50	—	—	$$$
Electrophoretic Coating	Paint, powder & polymer coatings	With care	15–35	—	500–1,000	$$
Aluminum Chromium Nitride PVD	PVD, CVD & thermal spray	Limited	1–5	2,900–3,400	—	$$$$
Aluminum Titanium Nitride PVD	PVD, CVD & thermal spray	Limited	1–5	3,200–3,800	—	$$$$
Chromium Nitride PVD	PVD, CVD & thermal spray	Limited	1–5	1,600–2,000	—	$$$$
Bead Blasting	Mechanical finishing & post-processing	Yes	0	—	—	$
Brushed Finish	Mechanical finishing & post-processing	Yes	0	—	—	$$
Deburring	Mechanical finishing & post-processing	Yes	0	—	—	$
Chemical Etching	Marking, decoration & colour	Yes	5–100	—	—	$$$
Embossing and Debossing	Marking, decoration & colour	Yes	200–1,000	—	—	$$$
Mechanical Engraving	Marking, decoration & colour	Yes	50–500	—	—	$$

60 more finishes accept copper alloy — see the full material × finish matrix →

Copper Alloy — frequently asked

Brass or bronze — what is the difference?

Brass is copper alloyed mainly with zinc; bronze is copper alloyed with tin, aluminum, silicon or manganese (historically tin). Brass is cheaper, yellower and machines faster; bronze is stronger, harder-wearing and more corrosion resistant, which is why bearings, propellers and bells are bronze while fittings, valves and decorative hardware are brass.

Which copper alloy has the best conductivity?

Oxygen-free C101 and C102 (101 % IACS) and electrolytic-tough-pitch C110 (100 % IACS). Every alloying element lowers it: C145 tellurium copper keeps ~93 %, C182 chromium copper ~80 %, C175 beryllium copper ~45 %, brass C260 ~28 %, aluminum bronze ~7 %. Pick pure copper for conductors and a high-copper alloy only where the conductor also needs strength.

Why is brass the easiest metal to machine?

The lead (or in lead-free grades, silicon or bismuth) forms tiny soft particles that break the chip into short segments, and the zinc keeps the alloy from smearing. C360 free-cutting brass is the 100 % reference on the machinability scale — parts cut two to three times faster than aluminum 6061 and five times faster than steel, with a mirror surface and no burr.

What is the best bronze for a bushing?

C932 (SAE 660) bearing bronze for most shafts: it embeds dirt, tolerates poor lubrication and runs against hardened steel. C936 for higher loads with marginal lubrication, C954 aluminum bronze for heavy slow loads and shock, and oil-impregnated sintered bronze where the bushing must run dry.

Which copper alloys survive seawater?

Copper-nickel (90/10 C706, 70/30 C715) for piping and condensers, aluminum bronze (C630, C955) for shafts, propellers and pump parts, silicon bronze (C655) for fasteners and welded work, and naval brass (C464) for fittings. Ordinary yellow brass dezincifies in seawater and should be avoided below the waterline.