Titanium Pipe for Seawater and Desalination Systems: Grade 2, Grade 12, ASTM and Buyer RFQ Guide

Titanium pipe for seawater is widely considered where chloride exposure, reliability and long equipment life matter more than the lowest initial material price. Seawater cooling loops, thermal desalination units, condensers, evaporators, offshore systems and chemical plants can all contain titanium piping or tubing. But a quotation request that says only “Grade 2 titanium pipe for seawater” still leaves important technical and commercial questions unanswered.

For an international buyer, the procurement task is to define the service conditions, select the correct product standard, identify whether Grade 2 or another approved titanium grade is required, and state the inspection and document package before comparing suppliers. This guide focuses on titanium pipe for desalination plants, seawater cooling systems and brine service. It is a procurement guide rather than a corrosion-design approval: the final grade and design limits must be confirmed by the project engineer, owner specification and applicable code.

Quick RFQ Summary: What to Send for Titanium Seawater Piping

Why Is Titanium Used in Seawater Systems?

Titanium develops a stable, tightly adherent oxide film that reforms in the presence of oxygen and water. That passive film is the reason commercially pure titanium has a long industrial history in seawater, brackish water, condensers and desalination equipment. Technical literature from the International Titanium Association describes strong general-corrosion performance of commercially pure titanium in seawater and points to localized crevice conditions—not uniform wall loss—as one of the more important design checks at elevated temperature.

For procurement teams, this distinction matters. A buyer should not simply ask whether titanium “resists seawater.” The useful question is whether the selected grade is approved for the project’s temperature, pH, oxygen condition, crevice geometry, chlorination, solids and galvanic design. The same material may perform very differently in a cool, well-aerated open line than in a hot, tightly gasketed and poorly aerated brine crevice.

Commercial reasons buyers consider titanium

• Corrosion allowance can often be reduced compared with materials that rely on sacrificial wall thickness, subject to the project design basis.
• Low density can reduce installed weight for large pipe, tube bundles and fabricated assemblies.
• High allowable seawater velocity in suitable designs can support compact piping and heat-transfer systems, although solids and impingement still require review.
• Long service experience in seawater condensers and desalination supports life-cycle purchasing decisions when downtime is expensive.
• Welded thin-wall products can be economically attractive in large heat-transfer surfaces and selected piping sizes.

Screening data in industry literature should not be used as a project design limit. The owner/EPC corrosion engineer should approve the grade, joint design, temperature and operating envelope.

Where Is Titanium Used in Desalination and Seawater Projects?

“Desalination” covers different process routes. Thermal plants and reverse-osmosis plants do not use the same materials in the same places, so a supplier needs to know the equipment tag and fluid duty rather than only the plant type.

Thermal desalination generally creates a stronger use case for titanium heat-transfer surfaces because hot seawater and brine contact large condenser and evaporator areas. Reverse-osmosis systems may use titanium more selectively. This is why an RFQ should identify the tag number, fluid and equipment function instead of using “desalination plant” as the only service description.

Grade 2 vs Grade 12 Titanium for Seawater

Grade 2 titanium (UNS R50400) is a commercially pure grade and is commonly used as a baseline material for seawater pipe, condenser tubing and general corrosion-resistant fabrication. Grade 12 titanium (UNS R53400) contains nickel and molybdenum additions and is often considered when the service has a more demanding localized-corrosion or crevice-corrosion envelope.

Grade 12 is not automatically “better” for every seawater purchase. If the owner specification approves Grade 2 for a cool, aerated seawater line, changing to Grade 12 can increase cost and reduce sourcing flexibility without solving a defined problem. Conversely, an elevated-temperature brine system with tight crevices, low pH or reduced oxygen should not be downgraded to Grade 2 simply to save purchase cost.

Industry corrosion literature reports that unalloyed titanium can become more sensitive to tight-crevice attack as temperature rises or pH falls, while Grade 12 extends the useful crevice-corrosion envelope in chloride brines. Treat such data as a screening tool, not a substitute for the project corrosion study.

For a broader grade comparison, see our Grade 2 vs Grade 12 titanium procurement guide.

Which ASTM Standard Should a Seawater Titanium RFQ Use?

One piping package can contain multiple titanium product forms, and each form can require a different standard. Using “ASTM titanium pipe” without identifying the standard is not sufficient.

As of September 2026, ASTM lists B861-24 for seamless pipe, B862-23 for welded pipe, B338-17(2026) for condenser/heat-exchanger tube, B363-23 for welding fittings and B381-26 for titanium forgings. The purchase order should identify the revision required by the project rather than assuming the supplier will choose it.

Pipe and heat exchanger tube are not interchangeable terms

One of the most common RFQ problems is asking for “titanium pipe” while providing a condenser tube size. If the product is installed as a heat-transfer tube bundle, ASTM B338 may be the correct purchasing route. If it is process piping, B861 or B862 may apply. The dimensional basis, tests and manufacturing route differ, so clarify the equipment function before quotation.

Service Data That Can Change Grade or Piping Design

A material supplier should not approve corrosion performance from one word such as “seawater.” A good buyer RFQ provides enough process data for the owner/EPC and supplier to identify questions before the purchase order.

1. Temperature and pH

General seawater corrosion resistance is only part of the design problem. Elevated temperature and lower pH can increase localized-corrosion concern in tight crevices. State the normal, maximum and design temperature, not only ambient conditions. For desalination brine, include both bulk pH and any chemical cleaning or dosing condition that can temporarily change pH.

2. Oxygen condition and stagnant crevices

Titanium’s passive film benefits from oxidizing conditions. Tight gasket faces, deposits, dead legs and stagnant zones can have a different local chemistry from the main flowing stream. If the system has long shutdown periods, low-flow operation or inaccessible crevices, include that information in the materials review.

3. Chlorination, oxidants and cleaning chemicals

Seawater systems often use chlorination or other treatment chemistry for biofouling control. Desalination plants can also use acid/alkaline cleaning chemicals. Give the dosing concentration, frequency, duration and maximum temperature. A cleaning cycle can be more aggressive than normal operation.

4. Suspended solids, sand and impingement

Titanium has strong erosion-corrosion performance in flowing seawater, but a pipe elbow receiving high-velocity sand-laden flow is not the same duty as a clean condenser tube. State the expected solids, particle size if known, velocity range and any direct-impingement location.

5. Galvanic interfaces

Titanium is relatively noble in seawater. When it is connected to less noble metals, the other metal can become the galvanic corrosion concern. The piping package should therefore identify mating flanges, tubesheets, valves, pumps, fasteners and electrical-isolation requirements. Do not leave material-interface decisions until installation.

6. Cathodic protection and hydrogen risk

Systems with impressed-current or sacrificial-anode cathodic protection require engineering review because excessive cathodic polarization can create hydrogen-related concerns for titanium under certain conditions. Include cathodic-protection data when the titanium is electrically connected to the protected system.

Dimensions, Lengths and End Preparation to Put on the PO

The product standard does not replace the dimensional purchase description. Buyers should define whether the requirement is based on NPS/schedule or exact OD × wall thickness, because titanium supply can be produced or stocked under different dimensional conventions.

Large welded titanium pipe, unusual wall thicknesses and long fixed lengths may be made to order. Give the supplier the complete size list at the RFQ stage so the quotation can reflect realistic mill yield, weld count, inspection and packaging.

QA, Testing and Documentation for Seawater Titanium

Inspection should be tied to the actual ASTM product standard and project quality plan. Adding generic phrases such as “100% NDT” without defining the method, acceptance criteria and reporting requirement can create commercial disputes.

• Material test certificate: require heat/lot identification, chemistry and mechanical properties applicable to the ordered specification.
• Traceability: define marking and transfer of heat/lot identity through cutting, forming and packaging.
• Dimensional inspection: specify the report format where OD, wall, length, ovality or fitting geometry must be documented.
• Pressure / NDT: use the tests required by the applicable standard and add project-specific supplementary examination only where needed.
• PMI: state whether positive material identification is required, for which items, and whether buyer/third-party witnessing is needed.
• Surface and cleanliness: define pickled, polished or as-manufactured surface where relevant; prevent carbon-steel contamination during handling and fabrication.
• Third-party inspection: specify agency, inspection level, hold/witness points and document approval timing before production.
• Certificate format: request EN 10204 3.1 or another certificate format only if required by the purchase specification.

ASTM B338 has product-specific test routes for welded and seamless heat-exchanger tubing, while B861 and B862 have their own pipe requirements. Do not copy a tube inspection clause into a pipe purchase order without checking applicability.

Complete RFQ Table for Titanium Pipe in Seawater or Desalination Service

Common Titanium Seawater Purchasing Mistakes

Ordering “Grade 2 pipe” without a product standard

This leaves seamless vs welded construction, inspection route and dimensional requirements unclear. Specify ASTM B861 or B862 for process pipe, or B338 when the product is heat exchanger tubing.

Using a general seawater claim as a corrosion guarantee

Temperature, crevices, oxygen, pH, chlorination, cleaning and galvanic design still matter. Material approval belongs in the project corrosion/materials review.

Automatically upgrading every line to Grade 12

Grade 12 can be valuable in more demanding service, but it should solve a defined corrosion/design requirement. An unnecessary alloy upgrade can increase purchase cost and lead time.

Ignoring fittings and flange material until after pipe quotation

A piping package should be reviewed as a system. Pipe, elbows, reducers, stub ends, flanges, gaskets and mating materials influence both procurement and corrosion design.

Comparing quotations with different QA scope

One supplier may price base ASTM testing while another includes third-party inspection, extra NDT and detailed reports. Normalize the inspection and document scope before comparing unit price.

Frequently Asked Questions

Related Titanium Products and Buyer Guides

Standards and revisions referenced in this article were checked for publication on September 9, 2026. Purchase orders should use the revision required by the project specification and verify current status before release.