C23000 Red Brass Tubes with a Polished Finish
C23000 is red brass, nominally 85 % copper and 15 % zinc, and its warm reddish-gold colour distinguishes it from the pale pink of high-copper tube. A polished finish turns that colour into a design feature: the tube is buffed to a uniform surface that can be left exposed or clear coated, while the alloy beneath continues to provide the corrosion performance expected of red brass in water service.
Polished tube is supplied for water supply systems, architectural trim, plumbing fittings and decorative hardware. The same product is also bought for low-voltage electrical components, since annealed red brass still conducts in the region of 28 - 32 % IACS, which is adequate for connectors and terminals.
Material Identity and Composition
| Element | Cu | Zn | Pb | Fe | Other elements |
|---|---|---|---|---|---|
| Weight % | 84.0 - 86.0 | Remainder | 0.05 max | 0.05 max | 0.10 max |
Composition is controlled so that the structure stays single-phase alpha brass, which is the basis of resistance to dezincification in water. Limited lead and iron also help the polished surface take and hold a uniform lustre, because inclusions show up as pits or streaks after buffing.
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 |
| Specific heat capacity | approx. 377 J/(kg.K) |
| 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 % |
Annealed tube is the usual choice for water supply because it can be bent and flared on site. Half hard and hard tempers are selected for exposed trim and fittings that must keep their shape without support.
Surface Finish Options and Dimensions
| Finish | Description | Typical use |
|---|---|---|
| Mill finish | As drawn, light oxide removed | Concealed pipework, further processing |
| Polished | Buffing to a uniform bright surface | Exposed water supply tube, trim |
| Polished and clear coated | Protective lacquer over the polished surface | Architectural and decorative use |
| Parameter | Range |
|---|---|
| Outside diameter | 10 - 150 mm |
| Wall thickness | 0.8 - 15 mm |
| Straight length | 1 - 6 m |
| Coils | up to 50 m |
Applications
Water supply and distribution tube in domestic and commercial plumbing, including valves and fittings
Architectural trim, door hardware, handrail inserts and lighting fixtures
Low-voltage connectors, switch components and terminals
Decorative marine hardware and non-critical fittings in freshwater environments
Industrial bushings, fasteners and stamped parts
Restoration work where period-appropriate reddish-gold metalwork is required
Processing Considerations
Annealing after cold working is carried out at 450 - 600 °C to restore ductility; the polished surface is produced after the last forming operation so that no processing marks remain. Machining uses sharp tooling and coolant to prevent material build-up on the cutting edge. TIG welding and soldering are both used with red brass, and overheating must be avoided because it vaporises zinc and can roughen or discolour the surface. Where appearance is critical, a protective clear coating is applied after polishing so that handling marks and tarnish are limited in service.
Because the finish is the visible selling point, packing matters as much as processing: tubes are sleeved, capped and separated so that the polished surfaces do not rub in transit.
Inspection Points
Chemical certificate confirming copper inside 84.0 - 86.0 % and low lead and iron
Surface inspection under even lighting for buffing marks, scratches and residual oxide
Dimensional check of diameter, wall, ovality and length
Pressure test and, where specified, eddy current examination
Cleanliness check of the bore before capping
FAQ
Q: Does polishing affect the corrosion resistance of the tube?
No. Polishing removes surface oxide and improves appearance; the corrosion behaviour depends on the alloy composition and the water chemistry, not on the finish itself.
Q: Why does polished red brass turn darker over time?
Copper alloys form a natural oxide film in air and water. A clear coating slows the change, and a light non-abrasive polish restores the original appearance when needed.
Q: Is polished tube suitable for buried water lines?
Buried lines are normally supplied mill finish, since the polished surface is not visible and may be damaged during installation. The alloy itself is well suited to water service.
Q: What temper is recommended for water supply work?
Annealed tube is preferred because it bends and flares easily. Half hard and hard tempers suit exposed trim and fittings that must hold their form.
Q: Which standards apply to this product?
Seamless brass tube is ordered to ASTM B135, welded brass tube to ASTM B587 and seamless red brass pipe to ASTM B43, with mechanical and dimensional requirements verified on each lot.
Q: How is polished tube protected during transport?
Tubes are cleaned, capped, sleeved and packed so that polished surfaces remain separated, which prevents rubbing marks in transit and storage.
