ASTM B861 Titanium Seamless Pipe: Grades, Schedules & Piping Guide
ASTM B861 Titanium Seamless Pipe: Process Piping, Schedules & Specification Guide
Table of Contents
- 1. What Is ASTM B861?
- 2. B861 vs. B338: Pipe vs. Tube — Know the Difference
- 3. Common B861 Grades for Piping
- 4. Pipe Schedules, OD & Wall Thickness
- 5. Pressure Ratings & Temperature Derating
- 6. Hydrostatic, Pneumatic & NDT Requirements
- 7. How to Write an ASTM B861 RFQ
- 8. Common Piping Specification Mistakes
- 9. Our Titanium Pipe Supply & Fabrication
- 10. FAQs
- 11. Related Standards
1. What Is ASTM B861?
ASTM B861 is the standard specification for titanium and titanium alloy seamless pipe. Unlike B338 (which covers heat exchanger tubes), B861 covers pipe intended for pressure piping systems — process lines, seawater transport, offshore risers, chemical transfer, and utility piping.
The ASME version is SB-861, referenced in ASME B31.3 (Process Piping), B31.1 (Power Piping), and Section VIII pressure vessel piping attachments.
Rule of thumb: If it carries fluid from point A to point B under pressure and is sized by nominal pipe size (NPS), you want B861 — not B338.
2. B861 vs. B338: Pipe vs. Tube — Know the Difference
| Parameter | ASTM B861 (Pipe) | ASTM B338 (Tube) |
|---|---|---|
| Primary use | Process piping, fluid transport | Heat exchangers, condensers, evaporators |
| Sizing system | NPS (Nominal Pipe Size) + Schedule | Actual OD × Wall (mm or inches) |
| Common sizes | NPS ½" to NPS 24" | OD 6 mm to 114 mm |
| Wall thickness | Sch 5S, 10S, 40S, 80S | 0.4 mm to 6 mm (exact) |
| Ends | Plain end, beveled end (PE/BE) | Plain cut, square cut |
| Code reference | ASME B31.3, B31.1, B31.4 | TEMA, HEI, customer exchanger spec |
Mixing these up is the #1 reason titanium piping projects get delayed. Pipe is for piping; tube is for heat transfer.
3. Common B861 Grades for Piping
| Grade | UNS | Key Advantage | Typical Piping Service |
|---|---|---|---|
| Gr.2 | R50400 | Best all-round corrosion resistance & weldability | Seawater, brine, chlorinated water, general chemical |
| Gr.7 | R52400 | Ti + Pd, resists reducing acids | HCl, H₂SO₄, phosphoric acid, bleach plants |
| Gr.9 | R56320 | Ti-3Al-2.5V, 20% stronger than Gr.2 | High-pressure hydraulic, aerospace ground support |
| Gr.12 | R53400 | Crevice corrosion resistance at elevated temp | Geothermal, FGD, hot chloride, sour service |
| Gr.5 | R56400 | Ti-6Al-4V, highest strength | High-pressure manifolds, structural piping |
For most chemical and seawater piping, Gr.2 Sch 10S or Sch 40S covers 70%+ of applications. When in doubt between Gr.2 and Gr.12, check the operating temperature and chloride concentration.
4. Pipe Schedules, OD & Wall Thickness
ASTM B861 pipes are available in standard stainless/titanium schedules:
| NPS | OD (mm) | Sch 5S WT (mm) | Sch 10S WT (mm) | Sch 40S WT (mm) | Sch 80S WT (mm) |
|---|---|---|---|---|---|
| ½" | 21.3 | 1.65 | 2.11 | 2.77 | 3.73 |
| 1" | 33.4 | 1.65 | 2.77 | 3.38 | 4.55 |
| 2" | 60.3 | 1.65 | 2.77 | 3.91 | 5.54 |
| 4" | 114.3 | 2.11 | 3.05 | 6.02 | 8.56 |
| 6" | 168.3 | 2.77 | 3.40 | 7.11 | 10.97 |
| 8" | 219.1 | 2.77 | 3.76 | 8.18 | 12.70 |
| 12" | 323.8 | 3.05 | 4.57 | 10.31 | 17.48 |
Sch 5S = minimum weight, low pressure; Sch 10S = general service; Sch 40S = standard pressure; Sch 80S = high pressure / mechanical strength.
5. Pressure Ratings & Temperature Derating
Titanium's allowable stress changes with temperature. Below is a simplified pressure reference for Gr.2 Sch 40S:
| Temp (°C) | Allowable Stress (MPa) | Sch 40S 2" Pipe MAWP (bar) |
|---|---|---|
| 20 | 138 | ~102 bar |
| 100 | 117 | ~87 bar |
| 200 | 103 | ~76 bar |
| 300 | 93 | ~69 bar |
Note: Values are approximate. Always calculate per ASME B31.3 paragraph 304.1 using the latest allowable stress tables.
Titanium's corrosion allowance is effectively zero — you don't need to over-thicken for wall loss over 20 years of service.
6. Hydrostatic, Pneumatic & NDT Requirements
ASTM B861 requires one of the following per ASTM B861 Section 8:
- Hydrostatic test: minimum 5 MPa (725 psi) or 1.5 × design pressure, whichever is greater
- Pneumatic test: permitted with purchaser approval, typically 1.1–1.2 × design pressure
- Ultrasonic test (UT): per ASTM E213 as alternative to hydrostatic (must be specified)
- Eddy current test: per ASTM E426, optional unless specified
Additional acceptance checks:
- Tensile test (UTS / YS / elongation)
- Flattening test (for seamless pipe)
- Flaring test (for smaller sizes)
- Chemical analysis with heat-number traceability
- EN 10204 3.1 MTR (3.2 with third-party witness)
7. How to Write an ASTM B861 RFQ
Weak: "Titanium pipe 2 inch, Grade 2"
Strong: ASTM B861 / SB-861 Gr.2 seamless pipe, NPS 2" Sch 40S, BE ends, 6096 mm RL, annealed, pickled, hydrostatic 10.3 MPa, EN 10204 3.1, heat no. traceable
Must specify:
- Standard: ASTM B861 or ASME SB-861
- Grade: Gr.2 / Gr.7 / Gr.9 / Gr.12
- NPS & Schedule: e.g., NPS 2" Sch 40S
- Ends: PE (plain) / BE (beveled 30°+37.5°)
- Length: RL (random 4–7 m) or fixed
- Surface: pickled / bright annealed
- Test: hydrostatic / UT / ET
- Certificate: EN 10204 3.1 / 3.2
8. Common Piping Specification Mistakes
| Mistake | Consequence | Fix |
|---|---|---|
| Writing "tube" when you mean "pipe" | Supplier quotes wrong product form | Use NPS + Schedule terminology for piping |
| No end condition specified | Plain ends on high-pressure line | Write "BE" (beveled end) for welded piping |
| Sch 40S where Sch 5S suffices | Unnecessary cost (titanium is expensive) | Review pressure calc; Sch 5S/10S often adequate |
| Mixing Gr.2 pipe with carbon-steel flanges | Galvanic corrosion at flange joint | Specify titanium or compatible alloy flanges |
| No post-weld heat treatment note | Field assumes stress relief needed | Gr.2 does NOT require PWHT; clarify on drawing |
9. Our Titanium Pipe Supply & Fabrication
- ASTM B861 / SB-861 Gr.2, Gr.7, Gr.9, Gr.12, Gr.5
- NPS ½" through NPS 24", Sch 5S to Sch 80S
- Plain end (PE) or beveled end (BE) preparation
- Hydrostatic test, UT, ET per customer specification
- Spool fabrication: pipe + flange + fitting pre-assembled
- Orbital welding support and procedure qualification (WPS/PQR)
- Pickled, passivated, VCI-wrapped, end-capped for export
- Full MTR + dimensional inspection report
We supply installation-ready titanium piping, not just bare pipe.
10. FAQs
Q: Can ASTM B861 pipe be used for cryogenic service?
Yes. Gr.1 and Gr.2 retain excellent toughness down to -250°C, making them suitable for LNG, liquid nitrogen, and cryogenic chemical transfer lines.
Q: What's the difference between B861 and B862 for my project?
B861 = seamless pipe (higher cost, better for high-pressure/critical). B862 = welded pipe (lower cost, suitable for larger diameters and less critical service). For NPS 8" and above, B862 is often specified to control cost.
Q: Does titanium pipe need insulation?
For personnel protection and energy conservation, yes. But unlike carbon steel, titanium does NOT need insulation for corrosion prevention — it won't rust from external moisture.
Q: Can I thread titanium pipe?
Threading is possible but rarely recommended. Titanium galls easily. Use butt-welding, flanged joints, or grooved couplings instead.
Q: Is post-weld heat treatment required for B861 Gr.2?
No. Commercially pure titanium Gr.2 does not require PWHT after welding. Stress relief (480–595°C) is optional and only needed for dimensional stability in precision assemblies.
11. Related Standards
Request ASTM B861 Titanium Pipe Quote
Send us:
- Grade & NPS (e.g., Gr.2, NPS 4")
- Schedule (5S / 10S / 40S / 80S)
- End condition (PE / BE)
- Length & quantity
- Test requirements (hydrostatic / UT)
- Certificate level (3.1 / 3.2)
We reply within 4 business hours with mill-direct pricing and lead time.
- Read titanium wire and titanium alloy wire: diameter classification
- Titanium wire: from brand selection to manufacturing process (2026 r
- Read titanium tube and titanium alloy tube: OD classification + comm
- Titanium pipe knowledge·tee + reducer selection 5 steps
- TA series vs TC series comparison: pure titanium vs titanium alloy s
Contact Person: Wang Xiaoning
Tel: +86-917-355-7966
Email: sales@sxqytd.com
WhatsApp: +86 188 2967 9311
Company: Shaanxi Qianyi Tuoda Technology Co., Ltd
Address: Floor 4, Building 4, No. 188 Gaoxin Avenue, High-tech Zone, Baoji City, Shaanxi Province, China