Grade 12 Titanium Alloy
ASTM B338 / ASME SB338 covers welded and seamless titanium and titanium alloy tubing for condensers and heat exchangers. Grade 12 (UNS R53400) is a near-alpha titanium alloy alloyed with 0.2–0.4% molybdenum and 0.6–0.9% nickel. The Mo-Ni addition improves elevated-temperature strength and - most importantly - resistance to crevice corrosion in hot chloride, seawater, and mildly reducing acid media, where commercially pure grades can suffer crevice attack.
Grade 12 retains the excellent fabricability and weldability of CP titanium while extending the service envelope, which is why it is specified for shell-and-tube exchangers, condensers and process piping in chemical plants, desalination trains, offshore platforms and pulp mills. Its German material number is 3.7105.
Chemical Composition (ASTM B338 Grade 12)
| Element | Composition Limit (wt%) | Element | Composition Limit (wt%) |
|---|---|---|---|
| Molybdenum (Mo) | 0.2 – 0.4 | Iron (Fe) | 0.30 max |
| Nickel (Ni) | 0.6 – 0.9 | Oxygen (O) | 0.25 max |
| Carbon (C) | 0.08 max | Nitrogen (N) | 0.03 max |
| Hydrogen (H) | 0.015 max | Titanium (Ti) | Balance |
Mechanical Properties and Condition
| Property | Value (min unless noted) |
|---|---|
| Tensile strength (Rm) | 483 MPa (70 ksi) |
| Yield strength, 0.2% offset (Rp0.2) | 345 MPa (50 ksi) |
| Elongation in 2 in (50 mm) | 18% (size-corrected per B338) |
| Density | 4.51 g/cm³ |
| Melting point | 1,668 °C (3,034 °F) |
| Supply condition | Annealed (stress-relieved or annealed per B338) |
Grade 12 is a near-alpha alloy and is supplied annealed. It is not strengthened by solution treatment and aging; strength comes from the Mo-Ni solid-solution effect, not from precipitation hardening.
Dimensional Range and Forms
ASTM B338 Grade 12 tubing is produced in both welded and seamless forms. Typical stock and production ranges:
| Form | Outside Diameter | Wall Thickness | Length |
|---|---|---|---|
| Seamless tube | 6.0 – 114.3 mm (custom to 219 mm) | 0.5 – 10.0 mm | Up to 12 m (random or cut lengths) |
| Welded tube | 6.0 – 219.1 mm | 0.6 – 6.0 mm | Up to 12 m |
| Heat-exchanger tube (U-bend / straight) | 12.7 – 38.1 mm (1/2" – 1-1/2") | 0.889 – 2.108 mm (BWG 20–14 typical) | As per tube-sheet layout |
Standard lengths, end finishes (plain, deburred, swaged) and tolerances are agreed per B338 and the exchanger drawing. U-bend tubes for shell-and-tube exchangers can be supplied with bend radii and straight-leg lengths per the fabrication drawing.
Inspection and Testing per ASTM B338
Tension test (room temperature) with values reported on the mill certificate.
Flattening test and flaring test (or ring-expansion for welded tube) to verify ductility and weld integrity.
Hydrostatic test (or pneumatic test when agreed), with non-destructive examination - eddy current or ultrasonic - for welded and seamless tube as specified.
Material test certificate per EN 10204 3.1 / 3.2, third-party inspection available.
Typical Applications
Shell-and-tube heat exchangers and condensers in chemical and petrochemical plants.
Desalination evaporators and brine heaters (hot seawater / brine contact).
Offshore oil & gas coolers and water-injection systems.
Pulp and paper bleach-plant heaters (chlorine dioxide and hypochlorite service).
Process piping and heater bundles handling hot chlorides and dilute reducing acids.
Why Choose Grade 12 over Grade 2 for Heat Exchangers?
Grade 2 CP titanium is adequate for many seawater and oxidizing chloride duties. Where the medium combines elevated temperature, crevice geometries, or reducing acid excursions, Grade 12's Mo-Ni addition resists crevice corrosion initiation that CP grades may experience, while providing roughly 40% higher yield strength. If crevice conditions are borderline, many specifiers step up to Grade 7 (Pd-alloyed) instead; Grade 12 remains the cost-effective middle ground for hot-chloride exchanger duty.
FAQ
Can Grade 12 titanium tubing be heat treated to higher strength?
No. Grade 12 is supplied annealed and is not heat-treatable to higher strength. Its strength advantage comes from the molybdenum-nickel solid-solution alloying.
What is the difference between ASTM B338 Grade 12 and Grade 2 tubing?
Grade 2 is commercially pure titanium (99.2% Ti minimum); Grade 12 adds 0.3% Mo and 0.8% Ni for higher strength and improved crevice-corrosion resistance in hot chloride and reducing-acid service. Grade 12 costs more but extends service life in aggressive exchanger duty.
Products Description
|
GR12 Titanium Tube |
ASTM B337 Gr12 Titanium Tube |
High Purity GR12 Titanium Tubing |
|
Ti-0.3Mo-0.8Ni Tube |
GR12 Titanium Heat Exchanger Tube |
Gr12 Titanium Hydraulic Tube |
|
Titanium Alloy Gr12 Pipe |
Titanium Alloy 12 Chemical Processing Pipe |
Cold Worked GR12 Titanium Tubing |
|
Seamless GR12 Titanium Tubing |
GR12 Titanium Pipe Supplier |
Precision GR12 Titanium Pipe |
|
Welded Titanium Gr12 Pipe |
GR12 Titanium Capillary Tube |
Titanium Gr12 Pipe Stock |
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