What C44300 Admiralty Brass Is
C44300 is an Admiralty brass: a copper-zinc alloy with additions of tin and a small controlled amount of arsenic. Tin improves resistance to corrosion and erosion, particularly in moving water, and arsenic inhibits dezincification. It should not be confused with naval brass - a different, higher-tin family of copper-zinc alloys such as C46400 and C48500 - although the two are frequently confused in trade literature. C44300 is a copper alloy classed as a wrought copper-zinc alloy with tin, and it is used in tube, pipe and sheet form.
Round condenser tube in this alloy is produced to ASTM B111/B111M and ASME SB111. Square, rectangular and other non-round sections of seamless brass tube - including square pipe - are produced to ASTM B135/B135M, the specification for seamless brass tube. Welded brass tube in round, square and rectangular sections is covered separately by ASTM B587. Sheet and plate versions are supplied to ASTM B171 and tube for U-bend exchanger construction to ASTM B395.
Chemical Composition
| Element | C44300 Admiralty brass limits (ASTM B111 / B135) |
|---|---|
| Copper (Cu) | 70.0 - 73.0 % |
| Tin (Sn) | 0.9 - 1.2 % |
| Arsenic (As) | 0.02 - 0.06 % |
| Iron (Fe) | 0.06 % max |
| Lead (Pb) | 0.07 % max |
| Zinc (Zn) | remainder |
| System | Designation for the same alloy |
|---|---|
| ASTM / ASME | UNS C44300 |
| EN 12451 | CuZn28Sn1As (CW706R) |
| JIS H3300 | C4430 |
| GB/T 5231 | HSn70-1 and HSn72-1 |
| AS 1569 | C44300 |
Composition limits matter here: a copper content outside 70-73 %, or arsenic outside 0.02-0.06 %, changes the corrosion behaviour of the alloy. When reading supplier documents for Admiralty brass square pipe, verify that the tabulated composition corresponds to C44300 rather than to a copper-zinc section of an entirely different family.
Mechanical and Physical Data
| Property | Typical value for C44300 |
|---|---|
| Density | about 8.53 g/cm³ |
| Melting range | approximately 900 - 940 degrees C |
| Elastic modulus | about 110 GPa |
| Coefficient of thermal expansion | about 20 × 10-6 per degree C |
| Thermal conductivity | about 110 W/(m·K) |
| Hardness, annealed | approximately 75 HB |
| Tensile, yield and elongation | as specified for the ordered temper under ASTM B111 or B135 |
Mechanical property requirements are stated by the governing specification for the temper actually ordered - annealed tube for forming and expansion duty, or a harder temper where a stiffer section is wanted. The values that matter commercially are the certified results on the material test certificate, tested from the production heat.
Square and Rectangular Brass Pipe: Where It Is Used
Heat exchangers and feedwater heaters: square and rectangular elements, spacer sections and structural tube used within exchanger assemblies.
Condensers, evaporators and distiller tubing: round C44300 tube to ASTM B111 remains the classic application, with the alloy's good cold forming making bent and U-shaped elements practical.
Marine and industrial equipment: parts requiring a combination of good corrosion resistance and excellent heat transfer characteristics.
Architectural and decorative work: square brass sections for handrails, balustrades, frames and trim, where the alloy takes a bright or polished appearance and can be lacquered.
Plumbing, fittings and general hardware: square and rectangular brass hollow sections machined or fabricated into assemblies.
Fabrication, Joining and Installation Notes
Cold working: C44300 has excellent cold-working behaviour and is easily formed and bent, which is the characteristic that makes it practical for exchanger elements and decorative sections.
Annealing: soft annealing is carried out in the 500-650 degrees C region and stress relief at lower temperatures, in each case in a protective atmosphere to limit oxide pick-up.
Machining: the alloy machines readily and takes a good surface finish; sharp tooling and suitable lubricant are recommended for hollow sections.
Joining: brazing and silver soldering are the preferred methods for fittings. Where welding is required, procedures must account for zinc volatilisation in the brass.
Installation: avoid contact with ammonia and ammonium compounds; keep dissimilar metals separated or correctly protected against galvanic attack; do not leave standing water in sections before commissioning.
Inspection and Acceptance Points
Confirm the material certificate reports C44300 chemistry, with copper 70-73 %, tin 0.9-1.2 % and arsenic 0.02-0.06 %.
Verify dimensions of the square or rectangular section: side length, wall thickness, corner radii, length and straightness against the drawing.
Check the specified tests - eddy current examination for tube product, and mechanical tests for the ordered temper.
Inspect surfaces for draw marks, laps and heavy oxide, and confirm that both the bore and outside are clean and dry.
Confirm marking and heat number traceability, and pack to protect corners, which are the first part of a square section to suffer handling damage.
FAQ
Q: Is C44300 Admiralty brass the same as naval brass?
No. C44300 is Admiralty brass, a copper-zinc-tin alloy with arsenic. Naval brass is a different, higher-tin copper-zinc family such as C46400 or C48500, with different properties and applications.
Q: Which standard covers square brass pipe?
Seamless brass tube in square, rectangular and other non-round sections is produced to ASTM B135/B135M. Welded brass tube in these sections is covered by ASTM B587, and round condenser tube in the same alloy by ASTM B111/B111M.
Q: Why is arsenic present in Admiralty brass?
Arsenic at 0.02-0.06 % suppresses dezincification, the selective leaching of zinc that otherwise degrades brass in contact with water.
Q: Can C44300 square pipe be welded?
Brazing and soldering are the standard joining methods. Welding is possible but requires procedures that manage zinc volatilisation, so it is normally avoided for thin-wall sections.
Q: What are the typical applications of C44300?
Condenser, evaporator and distiller tubing, feedwater heater elements, heat exchanger components, and square or rectangular sections used in architectural, decorative and general engineering work.
Q: How should square brass pipe be stored?
Indoors, dry, on supports that keep the sections clear of the ground, with corner protection in place and end caps fitted. Ammonia-bearing atmospheres must be avoided because they attack copper alloys.
