Titanium Grade 12 Flanges

Titanium Grade 12 (F-12, UNS R53400) Flanges to ASTM B381 and ASME B16.5

Dinesh Tube India supplies and exports titanium Grade 12 flanges from Mumbai for desalination, salt, chlor-alkali and chemical piping in India and abroad. Grade 12 flanges are machined from forgings to ASTM B381 / ASME SB381 Grade F-12 (UNS R53400, Werkstoff 3.7105), with dimensions to ASME B16.5, and are supplied with EN 10204 3.1 mill test certificates.

Grade 12 (Ti-0.3Mo-0.8Ni) resists crevice corrosion in hot chloride brines far better than Grade 2 and is about 40% stronger, at lower cost than Grade 7. A flange joint is a built-in crevice under the gasket, so in hot-brine service the flange should be the same grade as the Grade 12 pipe and Grade 12 fittings. For all grades, see our titanium flanges page.

Table of Contents

Grade 12 Flange Types
Specification & Sizes
Lap-Joint Option
F-12 vs F-2 vs F-7
Chemical Composition
Mechanical Properties
Applications
FAQs

Titanium Grade 12 F-12 flanges to ASTM B381

Titanium Grade 12 Flange Types

Weld Neck Flange

Butt-welded to the pipe; the best choice for higher pressure and cyclic service.

Slip-On Flange

Slides over the pipe and is fillet-welded; for lower-pressure lines.

Blind Flange

Closes pipe ends, nozzles and vessel openings.

Socket Weld Flange

For small-bore lines, usually 2" NPS and below.

Threaded Flange

For small-bore, low-pressure lines where welding is not possible.

Titanium Grade 12 ring type joint flange

Lap Joint & RTJ

Lap-joint flanges with stub ends, and ring-type-joint faces on request.

Lap-Joint Option: Grade 12 Stub End with Backing Flange

A solid Grade 12 flange is not always needed. In a lap-joint assembly, only the stub end touches the process fluid, so it is made in Grade 12 while the loose backing flange can be carbon steel, coated steel or stainless steel. This is the usual low-cost way to flange titanium piping, and the loose flange also makes bolt-hole alignment easier.

Stub end: Grade 12 (WPT12) to ASTM B363, long or short pattern. See Grade 12 pipe fittings.
Backing flange: lap-joint flange to ASME B16.5 in a cheaper material.
When to use solid F-12: where the flange face or bore is wetted, for blind flanges, or where the specification requires it.

F-12 vs F-2 vs F-7 Flanges

Point	F-2 (Grade 2)	F-12 (Grade 12)	F-7 (Grade 7)
Min. tensile / yield	345 / 275 MPa	483 / 345 MPa	345 / 275 MPa
Crevice corrosion under gaskets in hot brines	Fair	Excellent	Excellent
Dilute reducing acids	Poor to fair	Good	Best
Cost	Lowest	Moderate	Highest
Use with	Grade 2 pipe	Grade 12 pipe	Grade 7 pipe

Titanium Grade 12 Flange Chemical Composition (ASTM B381 F-12, %)

Element	F-12
Molybdenum (Mo)	0.2–0.4
Nickel (Ni)	0.6–0.9
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 12 Flange Mechanical Properties (Minimum)

Tensile Strength	Yield Strength (0.2%)	Elongation (4D)	Reduction of Area	Density
483 MPa (70 ksi)	345 MPa (50 ksi)	18%	25%	4.51 g/cm³ (0.163 lb/in³)

Check the current ASTM B381 edition (B381-26) and the mill certificate for governing values.

Why Use Grade 12 Flanges?

Gasket crevices: the area under a gasket is a tight crevice. Grade 12 resists crevice attack there in hot chloride brines where Grade 2 can fail.
Higher strength: about 40% higher minimum tensile than Grade 2.
Lower cost than Grade 7: no palladium, with similar crevice resistance in most brines.
Weight: about 57% of the weight of a steel flange of the same size.

Grade 12 is not suitable for hydrofluoric acid, fluorides or dry chlorine gas. For strongly reducing acids, Grade 7 is the better choice. See our Grade 12 sheets and plates page for more corrosion detail.

Need Grade 12 titanium flanges? Send the flange type, NPS, class, facing, bore schedule and quantity to kamlesh@dineshtube-india.com or call +91 83559 10913. You can also send an enquiry.

Marking, Gaskets and Bolting

Marking: a typical flange marking reads maker's mark, ASTM B381 F-12, size, class, facing, bore schedule and heat number.
Gaskets: use chloride-free gaskets such as PTFE-based types; avoid graphite in seawater service.
Bolting: choose bolt material for the outside environment; isolate dissimilar metals where seawater can bridge the joint.
Welding: GTAW with full argon shielding and internal purge, using ERTi-12 filler.

Titanium Grade 12 Flange Applications

Desalination brine and seawater piping
Salt evaporator and chlor-alkali brine lines
Hot-chloride process piping and vessel nozzles
Pulp bleaching and chlorine dioxide systems
Geothermal and hot seawater service

Desalination, brine and chemical uses of titanium Grade 12 flanges

Titanium Grade 12 Flanges: FAQs

Which standard covers titanium Grade 12 flanges?

The flange material is covered by ASTM B381 (ASME SB381) Grade F-12, the specification for titanium forgings. Flange dimensions follow ASME B16.5, with B16.47 for sizes above 24" and EN 1092-1 on request.

What is F-12 titanium?

F-12 is the ASTM B381 forging grade of titanium Grade 12 (UNS R53400, Werkstoff 3.7105), an alloy of titanium with 0.2–0.4% molybdenum and 0.6–0.9% nickel.

Which types of Grade 12 flanges are available?

Weld neck, slip-on, blind, socket weld, threaded and lap-joint flanges, with raised face, flat face or ring-type-joint facing.

Do I need a solid Grade 12 flange, or will a lap-joint flange do?

In many lines a Grade 12 stub end with a carbon-steel or coated lap-joint backing flange is enough, because only the stub end touches the fluid. Use a solid F-12 flange for blind flanges, wetted flange faces or where the specification calls for it.

Why use Grade 12 flanges instead of Grade 2?

The area under a gasket is a crevice. Grade 12 resists crevice corrosion in hot chloride brines far better than Grade 2 and is about 40% stronger, at lower cost than Grade 7.

What is the price of titanium Grade 12 flanges?

The price depends on flange type, NPS, class, facing, quantity and certification. Send your requirement to kamlesh@dineshtube-india.com or call +91 83559 10913 for a current quote.

Which certificates come with Grade 12 flanges?

Every supply comes with an EN 10204 3.1 mill test certificate showing heat number, chemical analysis and mechanical properties to ASTM B381. EN 10204 3.2 certificates and third-party inspection can be arranged on request.

Export Destinations for Titanium Grade 12 Flanges

We supply titanium Grade 12 flanges across India, including desalination, salt and chlor-alkali projects in Gujarat, Tamil Nadu, Maharashtra and Andhra Pradesh, and export to the Middle East (UAE, Saudi Arabia, Qatar, Oman, Kuwait, Bahrain), Asia (Bangladesh, Sri Lanka, Singapore, Malaysia, Vietnam), Africa (Egypt, South Africa) and Europe on request.