What C23000 Red Brass Thick Wall Pipe Is
C23000 is the UNS designation of the alloy known commercially as red brass or 85/15 brass, in which roughly 85 % copper is balanced by zinc. Unlike single-phase high-copper water tube grades, red brass is a solid-solution copper-zinc alloy: it gives up part of the copper content in exchange for higher strength, better machinability and a warmer reddish-gold colour that is often left visible in architectural work.
Thick wall construction turns that alloy into pipe rather than thin-wall tube. Where a tube is commonly specified by wall thickness in millimetres, pipe is ordered by nominal pipe size and schedule, so the wall becomes the primary pressure-retaining element. Heavy walls also add stiffness, allow rolled or cut threads without collapsing, and provide corrosion allowance for long-term water and marine service.
Typical mill supply covers seamless drawn pipe in the standard red brass schedules together with straight lengths and coils of tubing for plumbing and condenser duty. Chemistry and mechanical acceptance follow the applicable copper alloy pipe and tube specifications, so each heat is verified before dispatch.
Chemical Composition
The alloy is a simple two-element copper-zinc system with tightly restricted impurity limits, which is what gives red brass its reliable dezincification behaviour in water service.
| Element | Cu | Zn | Pb | Fe | Other elements |
|---|---|---|---|---|---|
| Weight % | 84.0 - 86.0 | Remainder | 0.05 max | 0.05 max | 0.10 max |
Low lead and low iron limits keep the structure single-phase alpha brass. The narrow copper range is important: below 84 % copper the alloy becomes more prone to selective attack in aggressive waters, while above 86 % the strength advantage over pure copper is lost.
Physical and Mechanical Properties
| Property | Typical value |
|---|---|
| Density | 8.7 - 8.8 g/cm³ |
| Melting range (solidus to liquidus) | approx. 970 - 1030 °C |
| Electrical conductivity (annealed) | 28 - 32 % IACS |
| Thermal conductivity at 20 °C | approx. 120 W/(m·K) |
| Modulus of elasticity in tension | approx. 110 - 117 GPa |
| Coefficient of thermal expansion (20 - 300 °C) | approx. 18.5 × 10-6 / °C |
| Temper | Tensile strength | Yield strength | Elongation |
|---|---|---|---|
| Annealed, O61 | 280 - 345 MPa | 95 - 150 MPa | 40 % min |
| Half hard, H02 | 380 - 430 MPa | 280 - 350 MPa | 20 % min |
| Hard, H04 | 450 - 520 MPa | 380 - 450 MPa | 8 - 15 % |
The annealed temper is used for bending and flaring operations; half hard and hard tempers are chosen where the pipe must resist deformation in service. Because red brass retains useful ductility across the range, heavy-wall pipe can be bent, swaged and threaded without intermediate anneals in most shop conditions.
Size Range and Wall Thickness Options
| Form | Outside diameter | Wall thickness | Length |
|---|---|---|---|
| Seamless pipe, standard schedule | 6 - 159 mm | 1.0 - 15 mm | Straight 1 - 6 m |
| Seamless pipe, extra heavy schedule | 6 - 108 mm | 2.0 - 15 mm | Straight 1 - 6 m |
| Tubing for plumbing runs | 10 - 150 mm | 0.8 - 5 mm | Straight or coils up to 50 m |
Dimensional tolerance, ovality and straightness are agreed at order stage. Threaded ends, beveled ends, plain ends and caps are available; for marine pipe runs a heavy schedule is normally quoted so that sacrificial wall thickness remains after threading.
Plumbing and Marine Applications
Potable water service lines, risers and distribution pipe in commercial buildings
Marine and offshore plumbing, deck wash and cooling water lines
Condenser and heat exchanger shells, water boxes and connecting pipework
Pipe nipples, fittings blanks and threaded couplings
Architectural exposed pipework and rainwater goods where the red-gold finish is retained
Industrial process water, pump lines and instrument piping
In seawater and brackish duty the alloy is chosen for its resistance to dezincification and seasonal cracking rather than for absolute inertness; correct wall allowance and clean installation practice remain decisive for service life.
Joining, Bending and Installation Notes
Soldering and brazing are the preferred joining methods and both rate excellent for this alloy. Gas shielded arc welding is workable, while coated metal arc welding and seam welding are not recommended because the zinc constituent volatilises under high heat input. Bending is carried out cold for small radii on annealed stock and hot formed where large deformation is needed; the practical hot working window lies in the region of 700 - 800 °C, followed by a controlled cooling.
Annealing after severe cold work is performed in the range of 450 - 600 °C to restore ductility. Cutting tools should be sharp and lubricated, because red brass work-hardens readily and dull tooling promotes galling on the cut face. Support spacing for exposed marine runs should follow the pipe schedule and expected vibration rather than the lighter spacing used for thin-wall copper tube.
Inspection Points Before Dispatch
Chemistry certificate confirming copper within 84.0 - 86.0 % and low lead and iron
Hydrostatic or pneumatic test of the finished pipe and tube
Eddy current or ultrasonic examination for wall defects on heavy-wall stock
Dimensional check of outside diameter, wall thickness, ovality and length
Visual inspection for drawing marks, roll marks and surface oxides
FAQ
Q: What does C23000 mean in a pipe specification?
C23000 is the UNS number for red brass, an 85 % copper and 15 % zinc alloy. When it appears on a pipe order it identifies both the chemistry family and the standard temper options available for that product.
Q: Why choose red brass instead of pure copper pipe?
Red brass offers higher strength, better machinability and improved resistance to dezincification and seasonal cracking in aggressive waters, at a slightly lower conductivity than high-copper grades.
Q: Can thick wall red brass pipe be threaded?
Yes. Threading up to standard pipe sizes is routine, and the heavy wall schedule is normally selected so that adequate wall remains under the thread roots.
Q: Is red brass pipe suitable for seawater?
It performs well in seawater and brackish water when the wall thickness includes a corrosion allowance and the installation avoids stagnant, aerated pockets that accelerate selective attack.
Q: Which standards apply to this product?
Seamless red brass pipe is ordered to ASTM B43, seamless brass tube to ASTM B135, welded brass tube to ASTM B587 and copper alloy heat exchanger tube to ASTM B111 or ASME SB111.
Q: What wall thickness should be quoted for a plumbing riser?
Wall thickness is driven by design pressure, water chemistry, expected vibration and the thread depth required. Specify the nominal pipe size, schedule and temper so the mill can confirm the wall allowance.
