Seamless Titanium Gr2 Pipe
What is a Seamless Titanium Gr2 Pipe?
Seamless Titanium Gr2 Pipe (UNS R50400, commercially pure titanium with 0.25 % maximum oxygen) is the workhorse of the titanium pipe family, produced from a solid billet without any welded seam. Its combination of outstanding seawater and oxidizing-acid resistance with a density 40 % lower than stainless steel is unmatched by any conventional alloy.
Grade 2 forms an extremely stable, self-healing titanium dioxide film that gives it near-total immunity to seawater, wet chlorine, hypochlorites, chlorine dioxide and oxidizing acids. It is also fully resistant to chloride stress-corrosion cracking and pitting — failure modes that plague stainless steels.
Manufactured to ASTM B338 (tube) and B861 (pipe), Titanium Gr2 seamless pipe is the reference material for seawater desalination brine lines, chlorine plant piping and offshore cooling systems where reliability over decades is required.
Titanium Grade 2 vs Grade 1 vs Grade 5 vs Grade 7: The Commercial-Purity Family
Commercially pure titanium grades differ mainly in interstitial content, which trades strength against ductility. Grade 2 is the balanced industry standard.
| Grade | Key Chemistry / Condition | Where It Fits |
|---|---|---|
| Grade 1 | lowest O (0.18 % max) | Most ductile and formable; lowest strength — used for deep-drawn and highly formed parts |
| Grade 2 | O 0.25 % max | The workhorse: ~345 MPa tensile with good formability and full seawater/oxidizing-acid resistance |
| Grade 5 (Ti-6Al-4V) | alloyed, ~895 MPa | Aerospace strength; less formable and lower crevice-corrosion performance than CP grades |
| Grade 7 | Gr2 + 0.15 % Pd | Gr2 mechanics with dramatically improved resistance in reducing acids |
Product Specifications
Specification data for Seamless Titanium Gr2 Pipe is compiled from the governing ASTM/ASME/EN standards and our routine production records; typical values are shown where a standard leaves a limit open.
| Category | Standard / Designation |
|---|---|
| Seamless Pipe | ASTM B861 / ASME SB861 |
| Seamless & Welded Tube | ASTM B338 / ASME SB338 |
| Welded Pipe | ASTM B862 |
| UNS Designation | R50400 |
| Werkstoff Number | 3.7035 |
Size and Weight Chart
| OD (mm) | Typical Wall (mm) | Weight (kg/m) |
|---|---|---|
| 6.35 | 0.9 | 0.07 |
| 9.53 | 0.9 | 0.11 |
| 12.7 | 1.0 | 0.17 |
| 16.0 | 1.2 | 0.25 |
| 19.05 | 1.2 | 0.3 |
| 25.4 | 1.65 | 0.56 |
| 31.75 | 1.65 | 0.7 |
| 38.1 | 2.0 | 1.02 |
| 50.8 | 2.5 | 1.71 |
| 63.5 | 2.5 | 2.16 |
| 76.2 | 3.0 | 3.11 |
| 101.6 | 4.0 | 5.53 |
The table lists typical production sizes with a common wall for each diameter; the full dimensional programme of the governing standard is available, and intermediate diameters, walls and lengths are cut to order.
Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| Titanium (Ti) | Balance | — |
| Oxygen (O) | — | 0.25 |
| Iron (Fe) | — | 0.30 |
| Carbon (C) | — | 0.08 |
| Nitrogen (N) | — | 0.03 |
| Hydrogen (H) | — | 0.015 |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength, min | 345 MPa (50 ksi) |
| Yield Strength (0.2 % offset), min | 275 MPa (40 ksi) |
| Elongation in 2 in. / 50 mm, min | 20 % |
| Hardness (typical) | 145 – 200 HBW |
| Condition | Annealed per ASTM B338/B861 |
Physical Properties
| Property | Value |
|---|---|
| Density | 4.51 g/cm³ |
| Melting Point | ≈ 1668 °C |
| Elastic Modulus | 103 GPa |
| Coefficient of Thermal Expansion (20–100 °C) | 8.6 µm/m·°C |
| Thermal Conductivity (at 20 °C) | 17.0 W/m·K |
| Electrical Resistivity | 54 µΩ·cm |
| Specific Heat Capacity | 523 J/kg·K |
Equivalent Grades
| Standard System | Designation |
|---|---|
| UNS | R50400 |
| Werkstoff Nr. | 3.7035 |
| DIN | Ti 2 |
| ASTM | B338 / B861 |
Why Grade 2 Is the Default Industrial Titanium
Grade 2 delivers the property combination that made titanium an industrial material: about 60 % the density of steel, a passive TiO2 film that is effectively immune to seawater, wet chlorine, hypochlorite and oxidizing acids, and a yield strength near 275 MPa that supports real pressure-part design. In chloride environments where 316 stainless pits and duplex grades struggle, Grade 2 operates for decades — which is why it dominates seawater and brine heat exchangers, chlorine-dioxide bleach washers and coastal power-plant condensers.
The seamless manufacturing route preserves these properties: vacuum double-melted billets, protected hot extrusion and cold pilgering followed by vacuum annealing keep interstitials low and the surface oxygen-free. Every length is certified to ASTM B338 (or B861) with full mechanical and NDT records.
Manufacturing Process
Our seamless production route for Seamless Titanium Gr2 Pipe follows these documented stages:
- Sponge Consolidation & Double Melting: High-purity titanium sponge is compacted with alloying additions and double- or triple-melted in vacuum consumable-arc furnaces for homogeneity.
- Billet Forging: Ingots are forged to extrusion rounds with ultrasonic inspection for internal defects.
- Hot Extrusion / Rolling: Billets, jacketed to protect against oxygen pickup, are hot-extruded or hot-rolled into tube shells.
- Cold Pilgering: Cold pilgering produces the final precision wall with excellent surface finish.
- Vacuum Annealing: Final annealing under vacuum (typically 650-800 °C) preserves the low interstitial content and bright surface.
- Testing & Certification: Tensile, hardness, flare/flattening, eddy-current and ultrasonic testing confirm conformity to ASTM B338/B861.
Surface Finish Options
- Vacuum-Annealed Bright: Standard condition; oxygen-free reflective surface.
- Pickled: For weld-prep and chemical service.
- Precision Ground / Polished: For instrumentation and specialty equipment.
Dimensional Tolerances
Delivered dimensions are verified against the tolerances below; tighter tolerances can be negotiated for instrumentation and precision applications.
| Dimension | Tolerance |
|---|---|
| OD, tube ≤ 25.4 mm (cold worked) | ± 0.10 mm |
| OD, tube 25.4 – 38.1 mm | ± 0.15 mm |
| OD, tube 38.1 – 50.8 mm | ± 0.20 mm |
| OD, hot-finished pipe ≥ 50.8 mm | ± 1 % of OD |
| Wall thickness | - 12.5 % under-tolerance (min-wall basis) |
| Straightness | ≤ 1 mm per metre |
| Cut length | + 10 / - 0 mm (fixed lengths) |
Common Industrial Applications
Because of its characteristic property profile, Seamless Titanium Gr2 Pipe is specified in the following industries and services:
- Desalination Plants: Brine, seawater intake and reject lines — Gr2 is the standard corrosion answer for multi-effect and RO plants.
- Chlor-Alkali & Chlorine Production: Wet-chlorine piping, cell covers and hypochlorite handling systems.
- Offshore & Coastal Power: Seawater cooling, condenser tubing and firewater piping immune to marine corrosion.
- Chemical Processing: Nitric acid, organic-acid and oxidizing-salt service where stainless steels pit.
- Pulp & Paper Bleaching: Chlorine-dioxide and hypochlorite bleach-wash piping.
- Food & Pharmaceutical: Corrosion-proof process piping with zero contamination risk.
Quality Assurance, Testing and Documentation
Every length of Seamless Titanium Gr2 Pipe passes through a documented quality-control chain before dispatch:
- Material Certification: EN 10204 3.1 mill test certificates are issued for every heat; 3.2 certification with third-party witness (TUV, SGS, BV) is available on request.
- Chemical & Mechanical Testing: Heat-level chemical analysis plus tensile, hardness and, where applicable, flattening, flaring and reverse-flattening tests per the governing standard.
- Non-Destructive Examination: 100 % eddy-current or ultrasonic testing and hydrostatic or pneumatic pressure testing in line with the standard's supplementary requirements.
- Dimensional & Visual Inspection: Full OD, wall thickness, ovality and length verification with visual surface inspection after pickling or finishing.
- Traceability & Marking: Heat numbers stenciled or banded on every length, maintaining complete melt-to-pipe traceability.
Export and Packaging
Pipes are bundled with steel strapping and fitted with plastic or steel end caps, then packed in seaworthy wooden cases or crates and secured in containers for long-distance ocean freight. Standard export documentation — commercial invoice, packing list, certificate of origin, mill test certificates and, where required, third-party inspection reports — accompanies every shipment. Container-load and bulk project orders receive priority production slots and consolidated shipping documentation.
Frequently Asked Questions
Q1. Why is titanium preferred over super duplex or 6Mo stainless for seawater piping?
A: Titanium is completely immune to pitting, crevice corrosion and SCC in seawater, while even premium stainless grades have velocity, temperature and crevice limits. Lifetime cost usually favors Gr2 despite the higher initial price.
Q2. Is Titanium Gr2 safe with dry chlorine?
A: No — dry chlorine reacts violently with titanium. Gr2 is exceptional with wet chlorine (above about 0.5 % water content) but must never contact completely dry chlorine gas.
Q3. What is the difference between Gr2 and Gr7 titanium pipe?
A: Gr7 adds 0.12–0.25 % palladium, extending corrosion resistance into reducing-acid environments (dilute hydrochloric and sulfuric acid) where Gr2 corrodes. Mechanically and in seawater they are equivalent.
Q4. Can titanium pipe be welded in the field?
A: Yes, by TIG with strict inert-gas shielding of the weld and both weld-root and face atmospheres; contamination by oxygen or nitrogen must be prevented to preserve ductility.
Ready to Request a Quotation?
Send us your size range, wall thickness/schedule, standard and quantity for Seamless Titanium Gr2 Pipe, and our engineering team will respond with a detailed technical and commercial offer within 24 hours. Custom sizes, third-party inspection and full export documentation are part of our standard service.
