ASTM B862 — Titanium and Titanium Alloy Welded Pipe
Engineering reference for ASTM B862-21, the standard specification for welded titanium and titanium alloy pipe. Covers dimensions, chemical composition, mechanical properties, weld qualification, and inspection requirements.
TLDR
ASTM B862-21 is the ASTM International specification for welded titanium and titanium alloy pipe. It is the primary standard referenced when titanium pipe is required in chemical processing, marine, and desalination service where corrosion resistance is critical and a welded (rather than seamless) construction is acceptable.
Quick Answer
What does ASTM B862 cover?
ASTM B862-21 specifies the requirements for welded titanium and titanium alloy pipe manufactured from sheet, strip, or plate that is formed and welded by an autogenous (no filler) or matching-filler process. It covers chemical composition, mechanical properties, dimensions, weld quality, hydraulic testing, and inspection. The standard is the dual of ASTM B861 (seamless pipe) and ASTM B337 (withdrawn, replaced by B861/B862).
Scope
ASTM B862 applies to welded pipe in nominal sizes NPS 1/8 through NPS 12 (and larger by agreement), in schedules 5S, 10S, 40S, and 80S, in titanium grades 1, 2, 7, 9, 11, 12, 16, 17, 26, and 27.
Key parameters covered:
- Outside diameter: 1/8 in to 12 in NPS (and larger by agreement)
- Wall thickness: schedules 5S, 10S, 40S, 80S (and special by agreement)
- Length: random, specified, or as-rolled
- Weld process: autogenous GTAW (TIG), plasma, or laser; filler metal permitted if matched to base
- Weld quality: 100 % radiographic or eddy-current per ASME Section V
- Surface finish: as-welded, pickled, polished, or as-agreed
Chemical Composition Requirements
Each grade covered by ASTM B862 has its own composition envelope. The most common grades and their key composition points:
| Grade | UNS | Key Alloying Elements |
|---|---|---|
| Grade 1 | R50250 | CP — softest, best formability |
| Grade 2 | R50400 | CP — most common, balanced properties |
| Grade 7 | R52400 | Grade 2 + 0.12–0.25 % Pd — enhanced corrosion resistance |
| Grade 9 | R56320 | Ti-3Al-2.5V — moderate strength, weldable |
| Grade 12 | R53400 | Ti-0.8Ni-0.3Mo — improved crevice corrosion resistance |
| Grade 23 | R56407 | Ti-6Al-4V ELI — medical and fracture-critical |
Mechanical Properties
| Grade | Tensile Strength (min) | Yield Strength (min) | Elongation (min) |
|---|---|---|---|
| Grade 1 | 240 MPa (35 ksi) | 170 MPa (25 ksi) | 24 % |
| Grade 2 | 345 MPa (50 ksi) | 275 MPa (40 ksi) | 20 % |
| Grade 7 | 345 MPa (50 ksi) | 275 MPa (40 ksi) | 20 % |
| Grade 9 | 620 MPa (90 ksi) | 483 MPa (70 ksi) | 16 % |
| Grade 12 | 483 MPa (70 ksi) | 345 MPa (50 ksi) | 18 % |
| Grade 23 | 860 MPa (125 ksi) | 759 MPa (110 ksi) | 10 % |
Weld Requirements
- Weld process qualification. Per ASME Section IX or AWS D17.1 (for aerospace).
- Weld inspection. 100 % radiographic per ASME Section V Article 2, or 100 % eddy-current per ASTM E309.
- Weld reinforcement. Flush or crowned within ±10 % of nominal wall, no undercutting.
- Post-weld cleaning. Pickle (HF/HNO₃) and passivate (per AMS 2700) to restore corrosion resistance in the heat-affected zone.
- Weld repair. Permitted with documented procedure; full re-inspection after repair.
Inspection and Testing
- Hydrostatic test. Required per ASTM B862 § 11 — typically held at 1.5× design pressure for 5 seconds.
- Pneumatic test. Permitted as alternative for thin-wall pipe; pressure relief mandatory.
- Dimensional inspection. OD, wall, length, ovality, straightness.
- Visual inspection. Surface defects, weld profile, ID accessibility.
- Chemical analysis. Per ASTM E120 or equivalent; reported on MTR.
- Mechanical testing. Tensile per ASTM E8, flattening per ASTM A370.
Surface Treatments
B862 pipe is commonly supplied with one of:
- As-welded — black mill scale, requires downstream pickling
- Pickled — HF/HNO₃ pickle, light grey matte surface
- Sandblasted — uniform matte texture, used as preparation for further coating
- Mechanically polished — for sanitary / food / pharmaceutical service
- Electropolished — sub-micron Ra for ultra-high-purity (UHP) service
Typical Applications
- Chemical processing: Reactor coil, heat-exchanger U-tubes, acid transfer lines
- Marine / desalination: Seawater cooling, brine heaters, evaporator shells
- Oil & gas: Downhole chemical injection, subsea umbilicals (Grade 29 / 12 hybrid)
- Power generation: Condenser tubes, auxiliary cooling
- Aerospace: Hydraulic lines (Grade 9), fuel and pneumatic systems
- Pharmaceutical: UHP water systems (electropolished)
Related Materials
- Grade 2 Titanium — Most common B862 pipe; chemical and marine service
- Grade 7 Titanium — Pd-stabilized for reducing acid service
- Grade 12 Titanium — Improved crevice corrosion in chloride / acid
- Grade 9 Titanium — Higher strength, aerospace hydraulic
Related Standards
- ASTM B861 — Seamless titanium pipe (companion standard)
- ASTM B337 — Withdrawn; replaced by B861/B862
- ASME B31.3 — Process piping code (typically invoked alongside B862)
- ASME Section IX — Welding qualification
- AMS 2700 — Passivation of welded-and-pickled pipe