Titanium is one of the few structural metals that essentially does not corrode in seawater. Its passive oxide film reforms on contact with water and oxygen, so pitting and general attack are absent in ambient seawater, and long-term exposure programs show no measurable corrosion after many years. This guide covers why titanium resists salt water, where the temperature and crevice limits sit, which grade to pick for desalination and offshore service, and which form and standard to order.
Beiyu Titanium supplies Grade 2, Grade 7 and Grade 12 titanium for seawater and marine service as tube, pipe, plate, sheet and bar, to ASTM B338, B861, B862, B265 and B348. Where the seawater-service order requires EN 10204 3.1 documentation and heat or lot traceability, define the reporting fields in the RFQ for quotation-stage confirmation.
Does titanium rust in salt water?
No. Titanium does not rust, and it does not suffer the pitting or general corrosion that attacks stainless steel and copper alloys in salt water. A thin, stable titanium dioxide (TiO2) film forms instantly on the surface and reforms the moment it is scratched, as long as moisture and oxygen are present. That self-healing film is why titanium is used for marine engineering hardware, seawater heat exchangers and desalination plant, where chloride attack is the main failure mode for other metals. In ambient-temperature seawater, titanium’s corrosion rate is effectively zero.
How well does titanium resist flowing and turbulent seawater?
Many marine failures come from erosion-corrosion, where fast or turbulent flow strips the protective film off a metal. Titanium keeps its film under high flow: it resists seawater velocities up to roughly 120 ft/s (about 37 m/s), far beyond the point where copper-nickel and other alloys erode. It also tolerates sand-laden and aerated seawater, and is not attacked by marine biofouling or the chlorination used to control it. For pumps, condenser inlets and high-velocity piping, that erosion resistance is often the deciding factor, not just static corrosion.
Where the seawater system also includes cathodic-protection or electrolytic hardware, review platinum-plated titanium anodes and ruthenium-iridium titanium anodes against the electrolyte, current-density and coating-life requirements.
At what temperature does seawater crevice corrosion start?
In open seawater at ambient temperature, titanium is effectively immune. The one mechanism to design against is crevice corrosion in tight gaps, such as under gaskets, deposits or tube-to-tubesheet joints, in hot seawater or brine. Grade choice sets that temperature ceiling:
| Grade | UNS | Seawater/brine crevice resistance | Typical use |
|---|---|---|---|
| Grade 2 (CP) | R50400 | Resists crevice attack to about 175°F (80°C) | Ambient and warm seawater, condensers, desalination |
| Grade 7 (Ti-0.15Pd) | R52400 | Extends crevice resistance to roughly 300°F (150°C) | Hot brine, reducing conditions, aggressive crevices |
| Grade 12 (Ti-0.3Mo-0.8Ni) | R53400 | Improved crevice resistance in hot concentrated brine | Hot brine and high-temperature chloride service |
Grade 2 commercially pure titanium covers the great majority of seawater service. When the service runs hot enough for crevice corrosion, such as concentrated or heated brine, tight sealed joints above roughly 80°C, the palladium-bearing Grade 7 or the Grade 12 alloy raises the ceiling. Beiyu supplies all three against the same documentation chain, so a project can step up a grade without changing supplier or paperwork.
For the full grade-by-duty breakdown across Grade 2, Grade 7, Grade 12 and the higher-strength alloys, see the seawater and marine grade-selection guide before freezing the material callout.
For crevice corrosion in hot chlorides, compare the temperature window with how Grade 12 is used in hot brine and crevice-prone chloride service when Grade 2 is near its seawater ceiling.
Which titanium grade do you pick for desalination and offshore service?
The application drives the grade. Match the service to the grade before you specify:
- Seawater condensers and coolers, ambient to warm: Grade 2 is the standard choice, supplied as thin-wall tube. It is the same commercially pure workhorse used across chemical industry corrosion service.
- MSF and RO desalination heat recovery and brine heaters: Grade 2 for the cooler stages; hot brine-heater sections and tight crevice zones may call for Grade 7 or Grade 12.
- Offshore platform seawater systems, firewater, cooling and injection: Grade 2 piping and plate, with Grade 7 where hot crevice conditions apply.
If you are choosing between commercially pure grades on strength and cost rather than corrosion, see our guide to choosing a CP titanium grade. Corrosion resistance is essentially identical across CP Grades 1 to 4, so the choice within CP is a strength and formability decision, not a corrosion one.
If part of the loop also sees reducing acids, treat that condition separately and compare it with Grade 7 for reducing-acid titanium service rather than assuming seawater performance covers the whole circuit.
Which form and standard do you order for seawater components?
Marine and desalination builds pull different mill products. Match the form and standard to the component:
| Component | Titanium form | Standard |
|---|---|---|
| Condenser and cooler tubing | Seamless or welded tube | ASTM B338 |
| Seawater process piping | Seamless or welded pipe | ASTM B861 / B862 |
| Tubesheets, vessel and box coolers | Plate and sheet | ASTM B265 |
| Pump shafts, fittings, valve parts | Bar and billet | ASTM B348 |
Beiyu supplies titanium across all of these forms, so a seawater heat exchanger or offshore build can source Grade 2 titanium tube, tubesheet Grade 2 titanium sheet and plate and piping against one grade and one documentation chain. For tube wall, tolerance and test detail, see our ASTM B338 titanium tube guide; for general chemical and heat-exchanger service, see Grade 2 titanium for chemical and heat-exchanger service.
If the buyer is still comparing metals rather than just titanium grades, the side-by-side guide to titanium, stainless and copper-nickel in seawater helps frame when titanium earns the higher purchase price.
For structures that need a steel load-bearing base with a corrosion-facing titanium layer, titanium-clad steel plate is another form to evaluate instead of specifying solid titanium through the full section.
How do you specify and certify titanium for seawater service?
A marine or desalination RFQ should state grade, form, standard and dimensions, plus the service so the mill can confirm fit:
- Grade and standard: Grade 2, 7 or 12 to ASTM B338 (tube), B861/B862 (pipe), B265 (plate) or B348 (bar).
- Dimensions: OD and wall for tube; thickness for plate; diameter for bar.
- Service: seawater temperature, flow velocity, and whether hot brine or sealed crevices are involved, so the grade ceiling is confirmed.
- Certification: EN 10204 3.1 mill test certificate with chemistry and mechanical results tied to the heat number.
Beiyu reviews each line against mill capability and supplies titanium for seawater, offshore and desalination corrosion service, documented by heat number.
Frequently asked questions
Does titanium rust in salt water?
No. Titanium does not rust and does not pit in salt water. A titanium dioxide film forms on the surface and self-heals whenever moisture and oxygen are present, so corrosion in ambient seawater is effectively zero, and long-term exposure shows no measurable attack. This is why titanium is a standard material for seawater condensers, offshore systems and desalination plant.
Which titanium grade is best for seawater and desalination?
Grade 2 commercially pure titanium is the standard choice for most seawater and desalination service. For hot concentrated brine or tight sealed crevices above about 80°C, Grade 7 (Ti-0.15Pd) or Grade 12 extends the crevice-corrosion ceiling.
What is the temperature limit for titanium in seawater?
Titanium is effectively immune in open seawater at all normal service temperatures. The practical limit is crevice corrosion in hot seawater or brine: Grade 2 resists it to about 175°F (80°C), while Grade 7 extends that to roughly 300°F (150°C).
Can titanium handle high-velocity and sandy seawater?
Yes. Titanium resists seawater flow to roughly 120 ft/s (37 m/s) and tolerates sand-laden and aerated seawater without erosion-corrosion, which is why it suits pumps and high-velocity condenser inlets.
Request a quote for titanium for seawater service
Before sending the enquiry, use the titanium RFQ checklist to confirm the grade, standard, dimensions, tolerance, quantity and certificate fields.
To quote titanium for seawater, offshore or desalination service, Beiyu needs: grade (2, 7 or 12), form (tube, pipe, plate, sheet or bar), standard, dimensions (OD and wall, or thickness), quantity, and the service (seawater temperature, velocity, and any hot-brine or crevice conditions). Send the drawing or spec and we review each line against mill capability before quoting, with EN 10204 3.1 MTC and heat-number traceability by order scope. Contact Beiyu Titanium for an RFQ.