Titanium Gr2 Tubing (UNS R50400)

Titanium Gr2 tubing is OD-sized, round instrumentation tube drawn from commercially pure (CP) unalloyed titanium, UNS R50400 (W.Nr. 3.7035), the workhorse CP grade, roughly 99% titanium with controlled interstitials. It carries process fluid or gas between components and seats into a compression fitting's ferrule set to make a leak-tight, make-and-break joint. Crestflo supplies Titanium Gr2 tube seamless and welded to ASTM B338, in both imperial and metric sizes, shipped annealed so it bends and cones cleanly into a ferrule. You reach for Titanium Gr2 tube when a line runs seawater, brine, wet chlorine, hypochlorite, or an oxidizing acid, the chloride-driven service where even high-alloy stainless pits, crevice-corrodes, or stress-corrosion cracks along the wetted run. Titanium is a different metal system from stainless: it resists these media through a self-healing titanium-dioxide passive film, which makes it effectively immune to chloride pitting, crevice attack at moderate temperatures, and chloride stress-corrosion cracking. It is also light, about 4.5 g/cc, roughly 40% the weight of steel. Standard items ship from stock; specials are built to order, with delivery running 6-8 weeks. Request a quote to price your run.

Reviewed by the Crestflo Engineering Team

Swagelok® and Parker® are trademarks of their respective owners; Crestflo is not affiliated, and interchange is dimensional.

Why Specify Titanium Gr2 Tubing

Tube is the long, continuous wetted surface of an instrument hookup. Unlike a fitting or a valve, it has no dead legs or packing bores, but it has length, every inch of it exposed to the media, and it has to survive the cold work of bending and ferrule make-up without cracking. On a seawater or chloride line that rules out most of the stainless family: a stainless tube that pits, crevice-corrodes, or stress-corrosion cracks midway along a run is as dead as one that fails at the fitting, and on a long, buried, or jacketed line that is the most expensive place to find a failure.

Titanium Gr2 solves that through a mechanism fundamentally different from stainless. Stainless and nickel alloys resist chlorides through a chromium-molybdenum-nitrogen alloying balance; titanium resists them through a tenacious, self-healing titanium-dioxide (TiO₂) passive film that reforms the instant it is scratched. That film is why Grade 2 is effectively immune to chloride pitting, crevice corrosion at moderate temperatures, and chloride stress-corrosion cracking, not merely resistant, but outside the failure modes that govern a stainless tube in seawater. Because titanium does not rely on a stainless alloying balance, a PREN (Pitting Resistance Equivalent Number) does not apply to it; PREN is a stainless/duplex index and is not quoted for titanium.

Be precise about where Grade 2 sits, though. The film thrives in oxidizing and chloride-bearing conditions and is weakened by strongly reducing acids, so titanium is not universal, it is poor in dry chlorine (which can ignite titanium), in hydrofluoric acid (which attacks it aggressively; avoid entirely), and in hot concentrated reducing acids like hydrochloric and sulfuric unless they are dilute, inhibited, or oxidizer-bearing. The corrosion-by-media detail is in the table further down. Two other traits earn titanium its place on a tube. First, weight: at a density of about 4.51 g/cm³ it is roughly 40% the weight of steel, which adds up across a long run racked over a topside, a subsea jumper, or a shipboard panel. Second, it is non-magnetic, a reason to specify it where magnetic permeability matters. One honest caveat on strength: Grade 2 yields at about 275 MPa (40 ksi), comparable to an austenitic stainless rather than a duplex, so there is no thinner-wall advantage, the case for titanium tube is corrosion immunity and weight, not pressure-per-wall. Its low elastic modulus (~103-105 GPa, roughly half that of steel) also shows up as more springback at the bender, worth knowing at fabrication rather than a drawback in service.

The full metallurgical picture, composition ranges, mechanical and physical properties, corrosion-by-media data, and grade-to-grade comparison, lives on the Titanium Grade 2 alloy grade page. This page stays on the tube: how it's made, sized, tempered, finished, tested, and matched to the fitting.

Also Specified As: CP Titanium Tube, Grade 2 Seamless Tubing, UNS R50400 Tube

Buyers and specifiers call this tube several ways, and each one points to the same commercially pure titanium. A requisition might read "Titanium Grade 2 seamless tubing," "CP titanium tube," "Ti Gr2 instrument tube," "UNS R50400 tube," "3.7035 tube," or "Grade 2 titanium tubing," and every one of them lands here. The formal designations are UNS R50400 (the US number) and Werkstoff 3.7035 (the European one); DIN calls it Ti2 / Ti 40, JIS calls it Class 2, and the common trade name is "50A" (Ti-50A). UNS R50400 and Werkstoff 3.7035 describe one and the same alloy, and a tube labeled Titanium Gr2 is routinely certified across those designations at once.

Scope: this is round, OD-sized instrumentation and fluid-system tube for compression and tube-fitting connections. It is not oilfield coiled tubing for downhole well intervention, not structural or ornamental tube, and not pipe specified by nominal pipe size (NPS) and schedule. One caution worth keeping on the PO: Grade 2 is not Grade 5. Grade 5 (Ti-6Al-4V, UNS R56400) is an alloyed, high-strength titanium for structural and aerospace loads, a different metal with lower weldability and corrosion resistance than CP Grade 2. Crestflo supplies Titanium Gr2 in instrumentation tube, fitting, and valve forms only, not mill bar, sheet, plate, or pipe.

Seamless vs Welded Titanium Gr2 Tubing

Both constructions are built to the same titanium tube specification, and both accept a compression fitting the same way. Seamless Titanium Gr2 tube is cold-drawn from a hollow with no longitudinal weld, which makes it the default where you want maximum integrity for higher-pressure, cyclic, or critical service. Welded-and-drawn Titanium Gr2 tube is formed from strip, seam-welded, then cold-drawn to size; it is dimensionally consistent and cost-effective for general instrument and fluid-system work. Both are covered by ASTM B338, the standard for seamless and welded titanium and titanium-alloy tube for condensers and heat exchangers, with its matching ASME SB-338 designation. Because Grade 2 is a single-phase alpha grade, fully alpha CP titanium rather than a two-phase duplex, there is no ferrite-balance check to run on the weld, which is one fewer acceptance step than a 2205 or 2507 tube carries. The grade's excellent weldability keeps the seam-welded-and-drawn tube sound and corrosion-resistant through the weld.

Not sure which construction to call out? The deep dives on seamless tubing and welded tubing walk through the trade-off before you commit a spec.

Titanium Gr2 Tube Attributes at a Glance

Titanium Gr2 Tube Sizes: OD, Wall & Imperial/Metric

Instrument tube is specified by its actual outside diameter and wall thickness, given in both imperial and metric units, never by NPS and schedule. The common instrument range runs fractional 1/8″ to 1″ and metric 6 to 12 mm; smaller 1/16″ small-bore tube and larger diameters up to 2″ (50 mm) are available to order. Wall thickness is chosen to carry the pressure and to suit the ferrule, and both OD and wall are held to the tolerances of ASTM B338. Because Titanium Gr2 is a moderate-strength CP grade rather than a high-strength duplex, it earns no thinner-wall credit: size the wall to the same pressure math you would run for an austenitic stainless, not thinner. Working pressure is not a single blanket figure: it is calculated from OD, wall thickness, and the alloy's allowable stress by the ASME B31.3 method, so it is stated per size and wall rather than as one rating for the grade.

Values per applicable standard; customizable to requirement. For how to work back from a target pressure to a wall thickness, see the tube sizing and wall thickness guide, and for the full dimensional matrix across the range, the tubing size chart.

Temper & Hardness: Annealed for Bending and Ferrule Seating

The single most important mechanical property of instrument tube is not its peak strength but its workability. Grade 2 is a single-phase alpha grade that is not strengthened by heat treatment, so it comes in one working condition, annealed, and that condition is what lets the tube bend around a radius and cone down under a ferrule without cracking, so the joint seats and seals the way a compression fitting is designed to. In the annealed condition Titanium Gr2 carries a tensile minimum of 345 MPa (50 ksi) with a 0.2% yield of 275 MPa (40 ksi) and elongation of at least 20%, with hardness around 160 HB (~80 HRB). That hardness is read on the Brinell or Rockwell B scale rather than HRC, because CP titanium is too soft for the HRC range to read meaningfully. Being fully alpha, Grade 2 has no ferrite phase to balance, and it stays tough from cryogenic temperatures up through its service range. Two handling notes follow from the metallurgy: titanium's low elastic modulus means more springback than steel when the tube is bent, so bends are set accordingly, and because titanium galls, make-up against the mating fitting is where the galling question lives (covered below). Specify the condition or hardness to your own standard on the RFQ and it is confirmed on the certificate.

Finishes & Cleanliness: Pickled, Bright-Anneal, Electropolish & Oxygen-Clean

Titanium Gr2 tube ships pickled/descaled and annealed as standard. Titanium passivates naturally, its TiO₂ film forms on contact with air, so the corrosion protection is inherent in the metal rather than applied as a coating; a pickle or passivation treatment cleans and refreshes that film rather than creating it. For high-purity gas, analytical, and oxygen service, bright-annealing, electropolishing (EP), and oxygen/UHP cleaning with capped-and-bagged packaging are available. Electropolishing lowers surface roughness and smooths the inner diameter, which matters where particle generation, moisture dry-down, or deposit build-up is the concern. Standard UHP electropolish surface-roughness targets can be specified right on the RFQ to your own standard; electropolished tubing and oxygen and UHP cleaning cover the options in detail. Finish and cleanliness figures follow the applicable standard and are customizable to requirement.

Titanium Gr2 Tube Standards: ASTM B338, B337 & ASME B31.3

Titanium Gr2 tube is covered by the titanium tube specification, not the stainless austenitic specs such as ASTM A269 or A213. Seamless and welded tube both fall under ASTM B338 (seamless and welded titanium tube), with its matching ASME boiler-code SB-338 designation; the equivalent pipe specification is ASTM B337 (ASME SB-337), which applies to NPS-and-schedule pipe rather than OD-sized instrument tube. Allowable working pressure for a given size and wall is calculated by the ASME B31.3 method. Where sour or chloride service applies, titanium alloys are addressed as corrosion-resistant alloys within NACE MR0175 / ISO 15156, and Grade 2 is supplied to that basis where the application qualifies. Crestflo holds the standard approvals that apply to instrumentation tube and is ISO 9001 / 14001 / 45001 and PED certified.

The full family of Titanium Grade 2 product-form specifications, including bar (B348), sheet and plate (B265), welded fittings (B363), and forgings (B381), is set out on the Titanium Grade 2 grade page; for tube, B338 is the one that applies.

Working Pressure: Calculated by the ASME B31.3 Method, Not Assumed

There is no single pressure rating for "Titanium Gr2 tube," and any supplier who quotes one is skipping the engineering. ASME B31.3 sets the method, relating wall thickness to pressure, diameter, the allowable stress value S, the weld-joint quality factor E, and the coefficient Y. Seamless tube carries a higher joint factor than welded, which is part of why seamless is chosen for higher-pressure work. Titanium Gr2 is a moderate-strength CP grade, its yield of 275 MPa (40 ksi) sits near an austenitic stainless rather than above it, and it derates with temperature, so expect no duplex-style strength bonus or thinner wall for the same pressure. What it buys instead is chloride immunity and low weight, and the thin-wall instrument sizes still carry ample pressure for analyzer, sample, and injection duty. Give us the OD, wall, temperature, and medium on the RFQ and the engineering team returns the calculated working pressure. Values per the applicable standard; customizable to requirement.

Corrosion & Service: Seawater, Wet Chlorine, Oxidizing Acids: and the Honest Limits

What a tube actually sees along its wetted length is the whole reason to specify Titanium Gr2 over stainless. This alloy was built for seawater and chloride duty, and that is exactly where it earns its place, but titanium is not universal, and the table below is honest about both sides. These are the grade's published, standard-referenced characteristics, not a per-tube rating; the corrosion allowance and suitability for a specific stream stay the specifier's call.

As an unalloyed alpha grade, Grade 2 holds useful mechanical strength to roughly 315 °C (600 °F) for continuous service, with tensile and yield derating as temperature rises, and it performs well down to cryogenic temperatures. Where the governing threat is a hot reducing acid rather than chlorides, use a nickel alloy such as Hastelloy C-276 or Monel 400; where you need chloride resistance together with much higher strength-per-wall, super-duplex 2507 is the better fit; and where the chloride load is heavy but titanium's reducing-acid limits or cost are a problem, a 6-moly super-austenitic like 254 SMO is the alternative. For the side-by-side with stainless, see titanium vs stainless steel. Match the alloy to the media and don't over-specify.

Testing, NDT & Material Verification

Every length of Titanium Gr2 tube is verified before it ships. ASTM B338 requires each tube to pass either a hydrostatic test or a nondestructive (eddy-current) test, and dimensional checks confirm OD, wall, and straightness against the ordered tolerances. Positive material identification (PMI) confirms the alloy on the material, which matters on titanium above almost any other grade: a mis-supplied stainless tube looks similar once finished but has none of the chloride immunity, and it pits and cracks in the exact service titanium was chosen to survive. NDT is done in-house; destructive testing, where a job calls for it, goes to ISO/IEC 17025-accredited labs, and third-party inspection is available on request.

For sour and chloride service, Titanium Gr2 tube material is supplied to NACE MR0175 / ISO 15156, where titanium alloys are addressed as corrosion-resistant alloys, when the application qualifies. Confirm the specific environmental limits in the standard against your application, H₂S partial pressure, temperature, and chloride content, and note the sour-service requirement on the RFQ.

Straight Lengths & Coiled Titanium Gr2 Tube

Titanium Gr2 tube ships as straight lengths for racked and rigidly supported runs, and as continuous coils for heat-tracing, long analyzer and sample lines, and chemical-injection and hydraulic bundles where a joint-free run is the whole point. Coiled tube keeps the count of mechanical joints down, which on a seawater, chloride, or subsea line is one fewer place to leak, and titanium's chloride-SCC immunity makes it a natural choice for the sample and injection cores that run in seawater and brine. The low weight compounds the benefit on long offshore and topside runs. Both forms are supplied annealed; call out length or coil length on the RFQ. For long-run and tracing applications, see coiled tubing; for thicker-wall high-pressure control lines, hydraulic tubing.

Material Traceability & Certification

Every length of Titanium Gr2 tube carries its own heat/lot number, and each order ships with an EN 10204 MTC 3.1 certificate as standard, 3.2 available on request. PMI confirms the grade at the part level, every time. That documentation backs the audit trails that desalination, offshore, and chlor-alkali jobs demand, the kind of work where a mis-specified or substituted tube in a long run is an expensive thing to discover in commissioning. On titanium the specific risk is substitution: a tube quietly supplied as stainless looks similar once finished but pits and cracks in the chloride service titanium was chosen to survive. Full detail is on the traceability page.

Applications for Titanium Gr2 Tubing

Titanium Gr2 tube earns its place wherever chlorides and oxidizing media govern the wetted run, the seawater-grade duty where pitting, crevice attack, and chloride SCC defeat stainless, and where the light weight is a bonus:

• Desalination and seawater cooling, SWRO, MSF, and MED plant instrument, sample, and analyzer lines, and seawater cooling-water instrumentation, where raw chloride service defeats standard stainless and titanium is the long-service standard. See desalination and water.
• Offshore and marine, platform and subsea instrument hook-ups, hydraulic control-line tube, and shipboard systems exposed to seawater and salt spray, where corrosion margin and light weight both count. See offshore and marine.
• Chlor-alkali and wet chlorine, chlorine, hypochlorite, and chlorine-dioxide dosing and process lines, a defining titanium application (provided the chlorine stays wet).
• Coastal and chemical processing, oxidizing-acid and analytical service, and coastal plant instrument lines where the ambient environment alone is corrosive.
• Non-magnetic and cryogenic requirements, lines where low magnetic permeability or low-temperature toughness governs, both of which the CP titanium structure provides.
• Aerospace and defense topside, weight-sensitive fluid-system tube where titanium's strength-to-weight and corrosion resistance both matter.

Where the service steps past titanium, to a hot reducing acid, to HF, or to a duty that needs high strength-per-wall, see the step-up grades in the next section.

Where Titanium Gr2 Stops: Reducing Acids, HF & High Strength-per-Wall

Titanium Gr2 is the correct pick for seawater, wet chlorine, and oxidizing chloride service, and knowing where it stops is as important as knowing what it handles. Where the duty is a hot or concentrated reducing acid, hydrochloric or sulfuric, or any hydrofluoric acid at all, titanium is the wrong metal and a nickel alloy such as Hastelloy C-276 or Monel 400 is the answer. Where you need chloride resistance together with much higher strength-per-wall in a thin, high-pressure tube, super-duplex 2507 beats up-rating titanium. And where the chloride load is heavy but titanium's reducing-acid limits or cost are a problem, a 6-moly super-austenitic like 254 SMO is the middle-ground alternative. For the baseline comparison that drives most titanium decisions, see titanium vs stainless steel. Match the alloy to the media and don't over-specify.

Pairing Titanium Gr2 Tube With Titanium Gr2 Fittings and Valves

A tube is one part of the hookup, and the joint is only as corrosion-resistant as its weakest metal. For a matched instrument run, pair this tube with Titanium Gr2 tube fittings and Titanium Gr2 instrumentation valves so the whole assembly, tube, ferrules, and valve body, carries the same chloride immunity and the same traceability. Putting a titanium tube into a 316 fitting just moves the failure point to the ferrule, to the first crevice the seawater finds. Crestflo supplies the tube alongside compression fittings tested to ASTM F1387, so the ferrule set seats correctly on the exact OD and wall you ordered, and the joint is a dimensional match rather than a mix of two suppliers' tolerances. One titanium-specific point on make-up: titanium galls readily under the high contact pressure where a ferrule bites the tube and where threads make up under torque, so anti-galling measures, a silver-plated ferrule or dissimilar hardware on the mating fitting, are offered on request where repeated make-up or high torque is expected. That hardware lives on the fitting side; the tube itself is simply the annealed titanium the ferrule grips.

Drop-In Interchange and the Tube-Plus-Fitting System

Crestflo Titanium Gr2 tube is cut and finished to standard OD and wall, so it drops into the compression fittings you already run, and the matching Titanium Gr2 fittings are built as dimensional interchange / equivalent parts for the major brands, with the fitting ends qualified to ASTM F1387. These are not "compatible" or "intermix" parts. Swagelok® and Parker® remain trademarks of their respective owners, and Crestflo is not affiliated; the interchange is strictly dimensional. Moving a run off a major brand? Request your Swagelok®/Parker® cross-reference and the engineering team maps your tube and fitting part numbers to Crestflo Titanium Gr2 equivalents. We don't publish a part-number table.

Origin & US-Serving Positioning

Crestflo manufactures for the US market. Standard product is of Indian origin; US or European melt is available on request, with full material traceability. Tube is engineered as a US drop-in and ships in 6-8 weeks, well under the 20+ weeks typical of the majors. If a project calls for a specific melt origin or TAA/DFARS handling, specify it on the RFQ and we'll address it straight, no hedging. We never claim "made in USA." See the US-origin compliance page for how we document it.

Why Crestflo for Titanium Gr2 Tubing

Crestflo operates as the instrumentation division of an export house with four decades behind it and formal recognition from the Government of India, with a proven Middle-East delivery record. That backing grounds a focused instrumentation brand built on a handful of clear advantages:

• Lead time of 6-8 weeks versus 20+ weeks typical of the majors, on standard stock and made-to-order specials alike.
• A matched system, tube plus F1387-tested fittings and ferrules that seat on the exact OD and wall you ordered, with silver anti-galling on the fitting side where titanium make-up calls for it.
• Both seamless and welded Titanium Gr2 tube, in both imperial and metric, straight or coiled.
• Heat-number marking plus MTC 3.1/3.2 on every order, PMI-confirmed, the anti-substitution guard on a corrosion-critical titanium part.
• NACE MR0175 / ISO 15156 material where the sour- or chloride-service application qualifies.
• ISO 9001 / 14001 / 45001 & PED certified, cost-competitive after US duties and tariffs, with small MOQs and private-label available.

We Engineer Confidence.

Request a Quote for Titanium Gr2 Tubing

Give us the details: seamless or welded, OD and wall, straight length or coil, finish and cleanliness, and the line conditions (media, pressure, temperature, sour-service requirement). We'll calculate the working pressure, confirm the spec, and schedule the run.

• Request a quote, the fastest path to pricing and lead time.
• Request a sample for qualification.
• Request your Swagelok®/Parker® cross-reference and we'll map your tube and fitting part numbers.

Datasheets and CAD are available to customers on request. Reach Crestflo's US sales desk at sales@crestflousa.com or +1 346 594 9005 (Houston, TX). Round out the system with Titanium Gr2 tube fittings and Titanium Gr2 valves, browse the tubing pillar for other grades and constructions, and see where this tube serves in desalination and water and offshore and marine.

Frequently Asked Questions

Related Pages

• Titanium Grade 2 alloy grade & corrosion data
• Titanium Gr2 tube fittings · Titanium Gr2 instrumentation valves
• Tubing pillar · Instrumentation tubing · Seamless tubing · Welded tubing
• Titanium vs stainless steel · 254 SMO
• ASTM B338 · ASME B31.3 · NACE MR0175 · EN 10204 MTC · Desalination & water · Offshore & marine