Titanium Tube and Pipe Range: Grades, Standards and Selection

Titanium Tube and Pipe Basics

Titanium tubing is the most widely specified titanium product form after plate, because it combines corrosion resistance with strength at low density for heat exchangers, condensers, hydraulic lines, exhaust systems and process piping. The terms tube and pipe are used slightly differently: pipe is dimensioned by nominal bore and wall schedule and used mainly for fluid transport, while tube is dimensioned by outside diameter and wall thickness and used for heat-transfer and precision applications. Both are available seamless and welded, and the choice between them is governed by the standard, the service and the economics of each project.

Seamless vs Welded Construction

Seamless tube is produced from a forged or extruded hollow, then reduced by cold pilgering and drawing to final dimensions. It has no weld seam, uniform wall thickness and the best fatigue and pressure performance, which is why pressure piping (ASTM B861) and most heat-exchanger tubing (ASTM B338) specify seamless. Welded tube is roll-formed from strip and welded longitudinally (TIG or plasma, often with the weld zone cold-worked), and is a cost-effective alternative for lower-pressure, non-code service (ASTM B862 covers welded pipe). For most corrosion service, a properly welded and tested titanium tube performs equivalently to seamless; the deciding factors are code requirements, availability of thin-wall sizes, and cost.

Grades and Governing Standards

Titanium tube and pipe are specified by grade plus standard, for example Grade 2 to ASTM B338 or Grade 12 to ASME B861. The key standards are:

ASTM B338 / ASME SB338 - seamless and welded tube for condensers and heat exchangers (Grades 1, 2, 3, 7, 9, 11, 12 and 5 in some revisions).

ASTM B861 / ASME B861 - seamless pipe for pressure service.

ASTM B862 / ASME B862 - welded pipe for pressure service.

ASTM B337 - the older seamless and welded pipe standard, still referenced in some regions and projects.

The grades most often ordered for tube are Grade 2 (general corrosion service), Grade 9 (stronger, formable tubing for aerospace and hydraulic lines), Grade 12 (hot chlorides and crevice environments) and Grade 7 (reducing acids). Grade 5 tube is available for high-strength applications such as racing exhausts and structural tubing, welded with care because of its stricter welding window.

Product Forms and Dimensional Range

The range of titanium tube products reflects the variety of service conditions:

Round tube - the dominant form; OD typically 3-150 mm seamless and up to 200 mm or more welded, wall 0.5-10 mm, length up to 6 m or coil for long runs.

Thin-wall tube - wall 0.5-2.0 mm for heat exchangers, condensers and capillary applications; supplied straight, as U-bends or in coils.

Thick-wall pipe - for high-pressure process piping and structural columns.

Square and rectangular tube - for architectural, marine and structural frames.

Threaded and instrument tube - for plumbing, instrumentation and hydraulic connections.

Coil tube - long continuous lengths for instrument lines and downhole applications.

Tolerances on OD, wall and length follow the governing standard, with tighter options (for example h8-h11 on OD) available for precision assemblies. Ends are supplied plain, beveled or threaded, and finishes include annealed and pickled, bright annealed, polished and sandblasted.

Manufacturing and Finishing

Seamless titanium tube is made by extrusion or piercing, cold pilgering, and drawing, with intermediate annealing in vacuum or inert-gas furnaces to restore ductility. The surface must be free of alpha-case - the oxygen-enriched, brittle layer formed during hot working in air - which is removed by pickling in an HF-HNO3 bath or by machining. Welded tube is formed from certified strip and welded with automatic TIG; the weld seam may be cold-rolled to match wall thickness. Final operations are straightening, cutting, surface treatment and 100% inspection. Because titanium work-hardens and conducts heat poorly, both forming and welding require equipment and procedures specific to titanium, which is a key reason to source from a specialist mill or processor.

Application-Based Selection

The fastest way to choose is by service:

Testing and Quality Assurance

Certified titanium tube is tested for chemistry, tensile properties and dimensional accuracy, plus hydrostatic (or pneumatic) pressure testing, eddy-current or ultrasonic inspection, and mechanical tests such as flattening, flaring and bend tests where the standard requires them. Each length is marked with standard, grade, OD, wall and heat number, and delivery includes a material test certificate to EN 10204 Type 3.1 with full chemistry and mechanical results. For code projects, third-party inspection and full traceability are available. Buyers should treat the certificate as part of the product - titanium tubing without certification is not an acceptable substitute in any pressure or corrosion-critical service.

FAQ

What is the difference between titanium tube and titanium pipe?

Tube is dimensioned by outside diameter and wall thickness and is used for heat exchangers and precision lines; pipe is dimensioned by nominal bore and schedule and is used for fluid transport. The product forms overlap, but the governing standards differ (ASTM B338/B861/B862).

Which titanium grade is best for heat-exchanger tubes?

Grade 2 for most seawater, brine and oxidising services, and Grade 12 where hot chlorides or crevice corrosion are a risk. Grade 7 is specified for reducing acids such as dilute hydrochloric acid.

Is welded titanium tube as good as seamless?

For most corrosion service, yes, when the weld is properly produced and tested. Seamless is required for pressure codes, high fatigue loads and thin-wall heat-exchanger tubes; welded pipe (ASTM B862) is the economical choice for larger diameters and lower pressures.

What wall thicknesses are available for titanium tube?

Typically 0.5-10 mm wall on 3-150 mm outside diameter seamless, with thinner capillary and thicker pressure-wall options on request. Wall tolerance is defined by the governing standard and can be tightened for precision applications.

Can titanium tube be supplied in coils?

Yes. Small-diameter, thin-wall Grade 2 (and some Grade 9) tube is available in coil form for instrument lines, hydraulic bundles and long continuous runs, with the annealed condition maintained for bendability.

What certificates should titanium tubing come with?

A material test certificate to EN 10204 Type 3.1 with chemistry, tensile results, test reports (hydrostatic, eddy current or ultrasonic) and heat numbers, plus markings on each length. Code projects may also require third-party inspection.