Admiralty brass earned its name in Royal Navy condensers. The job hasn't changed in a century: cooling steam with raw water that would eat plain copper alive, which a small tin addition, backed by arsenic inhibition, lets this alloy survive while keeping most of copper's conductivity. USA Piping Solution supplies admiralty brass fin tubes, typically C44300 base tube with integral low fins, for power plant and refinery condenser duty in brackish and seawater cooling. For fresh water and HVAC service where inhibited brass isn't needed, our Copper Finned Tubes page covers the standard option.
Specifications
| Specification | Details |
|---|---|
| Alloy | C44300 arsenical admiralty brass (C44400 antimonial / C44500 phosphorized variants on request) |
| Standard | ASTM B111 / ASME SB111 (condenser and heat-exchanger tube, incl. integral low-fin per B111's finned-tube provisions) |
| Construction | Integral low fin rolled from the tube wall; plain (bare) admiralty condenser tube also available |
| Typical OD | 15.9 – 31.8 mm (5/8" – 1-1/4") condenser sizes |
| Fin Geometry | Low fin, typically 19 – 26 fins per inch, to design |
| Tempers | Annealed (O61) standard for condenser service |
The Alloy Is the Product
| Element | C44300 Content | What It Does |
|---|---|---|
| Copper (Cu) | ~70–73% | Carries the thermal conductivity that makes the fin worth having |
| Zinc (Zn) | Balance (~27%) | Strength and cost; also the alloy's vulnerability, see arsenic below |
| Tin (Sn) | 0.9 – 1.2% | The “admiralty” addition: erosion and impingement resistance against flowing raw water |
| Arsenic (As) | 0.02 – 0.06% | Inhibits dezincification, the selective leaching of zinc that destroys uninhibited brass in seawater |
Uninhibited brass fails in salt water by dezincification: zinc leaches out, leaving a porous copper sponge with no strength. The arsenic addition in C44300 shuts that mechanism down, and the tin handles the mechanical side, impingement attack where water strikes the tube. That two-part defense is the entire reason this alloy still owns steam-surface-condenser duty a century on.
Applications
- Steam Surface Condensers: power plant condensers cooled by river, brackish, or seawater, the alloy's defining duty. See Condenser Tubes for the wider condenser range.
- Refinery Overhead Condensers: process condensing against raw cooling water.
- Feedwater Heaters & Coolers: low-pressure heaters in raw-water-cooled cycles.
- Marine Heat Exchangers: shipboard condensing and cooling duty.
For severely polluted or high-chloride seawater beyond admiralty's comfort zone, copper-nickel is the next step; see Copper Nickel 90/10 Pipes & Tubes.
Retubing a Condenser? Send the Tube Sheet Spec →
Testing, Certification & Availability
Tube is supplied to ASTM B111 with mill certification, eddy-current and hydrostatic testing per the standard, and full heat traceability; our Quality Policy page covers the program. Condenser retube orders move on tube-sheet drawings: send OD, gauge, fin spec, length, and quantity for availability.
Related Products
- Finned Tubes (all types)
- Copper Finned Tubes
- Condenser Tubes
- Copper Nickel 90/10 Pipes & Tubes
- Heat Exchanger Tubes & Pipes
Frequently Asked Questions
Why admiralty brass instead of plain copper for condenser fin tube?
Raw cooling water, river silt, brackish estuary, seawater, attacks plain copper by erosion and impingement at condenser velocities. Admiralty's tin addition resists that mechanical attack and its arsenic stops dezincification, at only a modest conductivity penalty versus pure copper.
Is C44300 suitable for ammonia service?
No. Copper alloys, admiralty included, are attacked by ammonia and ammonium compounds; stress corrosion cracking is the specific risk. Specify stainless or steel for ammonia-side duty.
Can you match an existing condenser's tube specification for a retube?
Yes, that's the most common admiralty order we see. Send the original tube sheet specification or a sample tube's measurements, OD, wall gauge, fin count, length, and we'll quote against it.