The tubes inside a heat exchanger do some of the hardest work in the system. They carry fluid, transfer heat and are exposed to pressure, temperature, flow velocity and chemistry. In harsh environments, especially marine and industrial cooling applications, the choice of tube material can determine how reliably the exchanger performs over time.
Non-ferrous tubes are widely used where corrosion resistance, thermal performance or compatibility with cooling water conditions is critical. These materials are especially important in seawater, brackish water and chemically challenging services.
What are non-ferrous tubes?
Non-ferrous metals are metals that do not contain iron as their main component. In heat exchanger tube applications, common non-ferrous choices can include copper alloys, brass, aluminium brass, cupro-nickel and titanium.
Each material behaves differently. A tube that is suitable for one cooling water system may be unsuitable for another. This is why tube selection should consider the full operating environment, not just the original drawing.
Key factors in tube material selection
When reviewing a heat exchanger for repair, retubing or replacement, several factors influence the right tube material:
- Cooling medium, such as fresh water, seawater or treated water
- Water velocity through the tubes
- Risk of erosion or impingement
- Chloride content and corrosion potential
- Fouling and cleaning requirements
- Operating temperature and pressure
- Compatibility with tube plates, end covers and gaskets
- Required service life and maintenance access
The aim is not simply to choose the strongest or most expensive material. The aim is to choose the material that is best matched to the duty.
When like-for-like replacement may not be best
Many heat exchangers are repaired using the same tube material originally fitted. In some cases, this is exactly the right approach. If the original unit has delivered good service life and the operating conditions have not changed, a like-for-like repair can be efficient and reliable.
However, operating conditions often change over time. Water treatment may differ from the original specification. Equipment may be working harder. Fouling may be more severe. A cooler may be used in a location or duty that was not part of its original design.
Signs that tube material should be reviewed include:
- Repeated tube leaks
- Localised corrosion or pitting
- Erosion at tube inlets
- Short service life after previous repairs
- Changes in cooling water source
- Increased cleaning frequency
- Tube failures concentrated in specific areas
In these cases, AMI Exchangers can assess whether an alternative tube material or revised design would provide better reliability.
Retubing and replacement support
Retubing can be a cost-effective way to extend the life of an existing heat exchanger, particularly when shells, covers or tube plates remain serviceable. It can also be an opportunity to improve reliability by reviewing materials and construction details.
For older or obsolete equipment, a replacement bundle or complete replacement exchanger may be more practical. AMI can work from drawings, sample units, site measurements or available equipment information to support the enquiry.
Practical engineering, not guesswork
The best tube material decision is based on operating evidence. If a cooler has failed, the failure pattern often tells a useful story. Location of leaks, deposits, corrosion markings and tube condition can all help identify whether the issue is material selection, flow behaviour, cleaning practice, water quality or age.
AMI Exchangers combines heat exchanger manufacturing experience with practical repair and replacement knowledge. Our team can help customers make informed decisions for tube material, retubing and exchanger replacement work.
If you need support with non-ferrous tubes, retubing or repeated tube failures, contact AMI Exchangers on +44 (0) 1429 860187 or email sales@ami-exchangers.co.uk.
