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How do you choose a heat exchanger tube material?
Short answer
Start with the more corrosive of the two fluids, usually the cooling water. Fresh water suits SS 304L or SS 316L, brackish water 2205 or 70/30 cupro-nickel, and seawater titanium, 90/10 cupro-nickel, 6Mo or super duplex. Then check the process side for acids, chlorides, temperature and fouling, and confirm velocity limits.
Key takeaways
In brief
- Cooling water decides a lot: Fresh water: SS 304L or SS 316L.
- Then the process side: Acids and sour fluids point to 825 or C276.
- Specify properly: Include OD, wall, length or U-bend radius, eddy-current testing and the specification (A213, A249, B338, B111, B163).
Cooling water decides a lot
Fresh water: SS 304L or SS 316L. Brackish water: 2205 or 70/30 CuNi. Seawater: titanium, 90/10 CuNi, 6Mo or super duplex.
Then the process side
Specify properly
Include OD, wall, length or U-bend radius, eddy-current testing and the specification (A213, A249, B338, B111, B163). See heat-exchanger tubes.
Five questions before choosing
- What is the chloride content and temperature of each fluid?
- What is the tube-side velocity, and does it stop for long periods?
- Is there sulphide, ammonia or other pollution in the cooling water?
- What is the tubesheet material, and will the tube be expanded or welded into it?
- What design life and cleaning method are planned?
Tube specifications by material
Related guides, comparisons and articles
Comparisons
Frequently asked questions
Is welded tube acceptable for heat exchangers?
Yes. Welded and annealed stainless tube to ASTM A249 is widely used and offers consistent wall thickness. Seamless tube is preferred for the highest pressures or where the specification requires it.
Which tube material resists biofouling best?
Copper-nickel alloys resist biofouling naturally. Titanium and stainless steels need cleaning or dosing to control fouling.
Should tubes be eddy-current tested?
Yes. Eddy-current testing of every tube is standard for heat-exchanger service and should be stated on the order.
Does Bright Tubes supply the materials discussed in this article?
Yes. Titanium Grade 2, Duplex 2205 Stainless Steel and related products are supplied from stock or mill-sourced, with EN 10204 certificates.
Can I get technical advice for my application?
Yes. Share your service conditions and specification, and our team can help shortlist suitable grades for your engineer to confirm.