Titanium Grade 7 Tubes

Titanium Grade 7 (Ti-0.15Pd, UNS R52400) Welded and Seamless Heat Exchanger Tubes to ASTM B338

Dinesh Tube India supplies and exports titanium Grade 7 tubes from Mumbai for heat exchangers, condensers and evaporators in acid and severe hot-chloride service. Our Grade 7 (UNS R52400, Werkstoff 3.7235) tubes are made to ASTM B338 / ASME SB338, welded or seamless, sized by outside diameter and wall thickness, and supplied with EN 10204 3.1 mill test certificates.

Grade 7 is commercially pure titanium with 0.12–0.25% palladium. It has the same strength as Grade 2, but the palladium keeps titanium passive in dilute reducing acids such as hydrochloric and sulphuric acid, and in the tightest hot-brine crevices at tubesheet joints. It is the most corrosion-resistant of the common titanium grades, and the most expensive. For all grades and condenser sizes, see our titanium tubes page.

Table of Contents

Specification & Sizes
OD × BWG Weight Table
Welded vs Seamless
Grade 7 vs Grade 12 vs Grade 2
Chemical Composition
Mechanical Properties
Why Grade 7 Tubes in Acid Service
Grade 7 Heat Exchanger Package
Applications
FAQs

Titanium Grade 7 heat exchanger tubes to ASTM B338

Titanium Grade 7 Tube Weight Table (kg/m)

OD	BWG 22 (0.71 mm)	BWG 20 (0.89 mm)	BWG 18 (1.24 mm)	BWG 16 (1.65 mm)
15.88 mm (5/8")	0.153	0.189	0.257	0.333
19.05 mm (3/4")	0.185	0.229	0.313	0.407
25.40 mm (1")	0.248	0.309	0.425	0.555
31.75 mm (1¼")	0.312	0.389	0.536	0.704
38.10 mm (1½")	0.376	0.469	0.648	0.852

Weight (kg/m) = (OD − wall) × wall × 0.01417, using titanium density 4.51 g/cm³. Other OD and wall combinations on request.

Welded vs Seamless Grade 7 Tube

Point	Welded Tube	Seamless Tube
How it is made	Formed from Grade 7 strip, TIG or plasma welded, annealed	Pierced or extruded hollow, cold pilgered or drawn
Typical use	Heat exchangers and condensers	Higher-pressure and small-bore tubing
Wall uniformity	Very uniform, ideal for thin walls	Good
Cost and lead time	Lower	Higher; both are mostly made to order in Grade 7

Titanium tube is welded by TIG or plasma arc, never by the ERW process used for carbon-steel tube.

Grade 7 vs Grade 12 vs Grade 2 Tube

Point	Grade 2	Grade 12	Grade 7
Min. tensile / yield	345 / 275 MPa	483 / 345 MPa	345 / 275 MPa
Seawater condensers	Excellent; standard choice	Excellent	Excellent (rarely needed)
Crevice corrosion in hot brines	Fair	Excellent	Excellent
Dilute reducing acids (HCl, H₂SO₄)	Poor to fair	Good	Best
Palladium	None	None	0.12–0.25%
Cost	Lowest	Moderate	Highest

If the main problem is hot-brine crevice corrosion rather than acid, Grade 12 tube is usually enough and costs less. Grade 16 (Ti-0.05Pd) has about a third of the palladium of Grade 7 and is sometimes accepted as a lower-cost alternative; check your specification first.

Titanium Grade 7 Tube Chemical Composition (ASTM B338, %)

Element	Grade 7
Palladium (Pd)	0.12–0.25
Iron (Fe), max	0.30
Oxygen (O), max	0.25
Carbon (C), max	0.08
Nitrogen (N), max	0.03
Hydrogen (H), max	0.015
Titanium (Ti)	Balance

Titanium Grade 7 Tube Mechanical Properties (Minimum)

Tensile Strength	Yield Strength (0.2%)	Elongation	Density
345 MPa (50 ksi)	275 MPa (40 ksi)	20%	4.51 g/cm³ (0.163 lb/in³)

Check the current ASTM B338 edition (B338-17, reapproved 2026) and the mill certificate for governing values.

Why Grade 7 Tubes in Acid Service?

Stable passive film: palladium keeps titanium's protective oxide stable in dilute hydrochloric and sulphuric acid, where Grade 2 tubes corrode.
Tubesheet crevices: the joint between tube and tubesheet, and deposits on the tube, form crevices where acid concentrates. Grade 7 resists attack there at higher temperatures than Grade 2.
Thin walls, good heat transfer: Grade 7 forms and welds like Grade 2, so thin-wall welded tube is practical.
Limits: not suitable for hydrofluoric acid, fluorides or dry chlorine gas, and not intended for hot concentrated HCl or H₂SO₄, where zirconium or tantalum may be needed.

Grade 7 Heat Exchanger Package

In acid service, the tubesheet, channel and connecting piping should also be Grade 7, so the joints do not become the weak points. We can supply:

Grade 7 Plate

B265 Grade 7 plate for tubesheets, channels and linings, or as cladding.

Grade 7 Pipes

B861 seamless and B862 welded pipe for nozzles and process lines.

Grade 7 Flanges

F-7 flanges to ASTM B381, with WPT7 fittings to ASTM B363.

Need Grade 7 titanium tubes? Send the OD, wall (BWG or mm), length, welded or seamless, straight or U-bent, quantity and process media to kamlesh@dineshtube-india.com or call +91 83559 10913. You can also send an enquiry.

Fabrication Notes

Tube-to-tubesheet joints: expanded, seal-welded or strength-welded; GTAW with full argon shielding and matching ERTi-7 filler where welded, so the weld keeps its acid resistance.
U-bending: allow for wall thinning on tight bends; stress relieving of bends may be specified.
Iron contamination: keep titanium tubes away from carbon-steel tools and work areas.
Lead time: Grade 7 tube is mostly made to order; plan for longer delivery than Grade 2.

Titanium Grade 7 Tube Applications

Heat exchangers handling dilute hydrochloric or sulphuric acid
Chlor-alkali and chlorine dioxide plant exchangers
Hydrometallurgy leach-liquor heaters and coolers
Severe hot-brine evaporators and brine heaters
PTA, acetic acid and fine-chemical process exchangers

Acid, chlor-alkali and chemical heat exchanger uses of titanium Grade 7 tubes

Titanium Grade 7 Tubes: FAQs

Which standard covers titanium Grade 7 tubes?

Titanium Grade 7 tubes for condensers and heat exchangers are made to ASTM B338 (ASME SB338), which covers seamless and welded titanium tube sized by outside diameter and wall thickness.

What is titanium Grade 7?

Grade 7 (UNS R52400, Werkstoff 3.7235) is commercially pure titanium with 0.12–0.25% palladium. It has the same strength as Grade 2, with much better resistance to dilute reducing acids and crevice corrosion.

Why use Grade 7 tubes instead of Grade 2?

Grade 7's palladium keeps titanium passive in dilute hydrochloric and sulphuric acid and in the tightest hot-brine crevices at tubesheet joints, where Grade 2 tubes can corrode. For ordinary seawater condensers, Grade 2 is enough.

Should I choose Grade 7 or Grade 12 tubes?

Grade 7 is best where reducing acids are present. Grade 12 is stronger and lower cost and is usually enough for hot brines without acid. The tubesheet should match the tube grade.

Are Grade 7 tubes welded or seamless?

Both are available to ASTM B338. Welded tube is the usual choice for heat exchangers because of its uniform thin wall and lower cost. Grade 7 tube is mostly made to order.

How much does a titanium Grade 7 tube weigh?

Weight in kg/m = (OD − wall) × wall × 0.01417, with OD and wall in mm. For example, a 19.05 × 0.89 mm (BWG 20) tube weighs about 0.23 kg/m.

What is the price of titanium Grade 7 tubes?

Grade 7 costs more than Grade 2 and Grade 12 because of its palladium content. The price depends on OD, wall, length, welded or seamless, U-bending, quantity and certification. Send your requirement to kamlesh@dineshtube-india.com or call +91 83559 10913 for a quote.

Export Destinations for Titanium Grade 7 Tubes

We supply titanium Grade 7 tubes across India to heat-exchanger fabricators and chemical, chlor-alkali and hydrometallurgy plants in Gujarat, Maharashtra, Tamil Nadu and Andhra Pradesh, and export to the Middle East (UAE, Saudi Arabia, Qatar, Oman, Kuwait, Bahrain), Asia (Japan, South Korea, Singapore, Malaysia, Vietnam, Bangladesh), Africa (Egypt, South Africa) and Europe on request.