Drawing No. EH–MT–006 // Engineering Materials
Brass Properties
Reviewed September 2026
C26000 Cartridge Brass (about 70% Cu, 30% Zn) in H01 quarter-hard condition is used as the representative brass. It offers good formability, corrosion resistance and machinability with much lower thermal conductivity than pure copper.
Representative properties
Switch units without changing the underlying material reference.
What changes these properties?
Engineering variability
- Mechanical values are explicitly tied to H01 quarter-hard flat-product data.
- The displayed Poisson ratio is derived from CDA Young’s and shear moduli.
- Zinc content and cold work strongly influence strength and ductility.
- Thermal and corrosion properties depend on composition and environment.
Selection note
Useful for formed parts, fittings, hardware and heat-transfer components where copper-like corrosion behavior and good manufacturability are useful.
Do not combine strength from one grade/condition with modulus, thermal data or temperature limits from another without checking compatibility. Where the overview shows a range, it is intended to expose variability—not establish allowable bounds.
Brass in practice
A copper-zinc alloy chosen for machinability and cost, with one failure mode that governs nearly every specification decision.
Where it is specified
Plumbing fittings, valve bodies, gas fittings, instrument bodies, electrical terminals and connectors, locks and keys, marine hardware, musical instruments, and decorative architectural work.
The composition splits the family. Alpha brasses below about 37% zinc (C26000 cartridge brass, 70/30) are ductile and cold-formable — used for drawn shells and deep-formed parts. Duplex alpha-beta brasses around 40% zinc (C38500 free-cutting brass, CW614N) are hot-forgeable and outstandingly machinable, which is why they dominate turned fittings.
Chosen over what
Against bronze: brass is cheaper and much easier to machine; bronze (copper-tin, aluminium bronze) is better in seawater and for bearing duty.
Against stainless: far better machinability and no galling, at lower cost, but lower strength and vulnerable to ammonia and to dezincification.
Against plastic fittings: brass tolerates heat, UV, mechanical abuse and sealing loads that polymers do not, which is why it persists in plumbing despite cheaper alternatives.
How it fails
Dezincification is the defining failure. In stagnant, soft, chlorinated or acidic water, zinc leaches selectively and leaves a porous, spongy copper residue that retains the part's shape but almost none of its strength — a fitting can look sound and fail at a touch. The remedy is a dezincification-resistant (DZR / CR) grade with arsenic addition, such as CW602N, and many water authorities mandate it.
Season cracking — stress-corrosion cracking in ammonia or amines, historically discovered in cartridge cases stored in stables. Residual drawing stresses plus a trace of ammonia is sufficient, and the fix is a stress-relief anneal after forming.
Erosion-corrosion in high-velocity water, as with copper.
Lead leaching. Free-machining brasses have historically contained 2–3% lead for chip breaking, and drinking-water regulation has progressively forced a move to low-lead and lead-free grades, which machine less well.
Fabrication notes
Machinability is the best of any common metal — free-cutting brass C36000 is the 100% reference against which all other machinability ratings are quoted. It produces short broken chips at high speed with minimal tool wear, which is why high-volume turned parts default to it.
Hot forging of alpha-beta grades at 650–750 °C is fast and cheap and is how most valve bodies are made.
Joining is by soldering or brazing; fusion welding is uncommon because zinc volatilises at welding temperature, producing porosity and zinc oxide fume — a genuine health hazard (metal fume fever) requiring extraction.
Stress relief after cold forming is routine where the part will see moisture or ammonia, typically 250–300 °C.
Specifications and standards
ASTM B16 (free-cutting bar), B36 (sheet/strip), B283 (forgings); EN 12164/12165 for rod and forging stock; BS EN 12502 for dezincification guidance; NSF/ANSI 61 and the EU Drinking Water Directive for potable-water contact; AS/NZS 2345 for dezincification resistance testing.
References
Copper Development Association publications on dezincification and DZR alloys; ASM Handbook Vol. 2; EN 12502-2 on copper alloy corrosion in water systems.
Property interpretation
Stiffness vs strength
Young’s modulus controls elastic deformation. Yield or fracture strength controls how far the material can be stressed. These are separate material characteristics.
Thermal response
Thermal conductivity controls temperature gradients, specific heat contributes to thermal inertia, and expansion controls thermally induced strain when movement is restrained.
Temperature transition
The final property card is deliberately labeled “melting / transition.” Metals often have a solidus–liquidus range; amorphous polymers and glass use softening or glass-transition concepts; concrete and wood decompose instead of exhibiting one clean melt point.
Technical sources
Source hierarchy favors manufacturers, industry associations, standards bodies and government engineering references. Strength data must still be reconciled with the exact procurement specification.