When nickel, titanium or zirconium alloys are not enough...

• Immune to numerous acids and chemicals (corrosion tables)
• Better corrosion resistance than nickel alloys, titanium or zirconium
• High strength and stiffness in vacuum and inert gas up to 2000°C (3600°F)
• Can become brittle when used in oxygen above 300°C
• High purity and biocompatibilty
• Tantalum grades, specifications and chemistry
• Datasheet for tantalum
• Socket weld flange features and benefits

Tantalum socket weld flanges are best known for its unmatched corrosion resistance and chemical inertness. Tantalum socket weld flanges have a similar corrosion resistance to that of glass, but all of the typical mechanical and electrical properties of a metal.

Tantalum socket weld flanges are also extremely stable at high temperatures, since tantalum has a melting point around 3000°C. High temperature applications require vaccum or inert gas since tantalum may embrittle when used in oxygen rich environments above 250°C.  Tantalum socket weld flanges are also one of the most bio-compatible metals available and is also radio-opaque due to its high density (16.68 g/cm3).

All tantalum socket weld flanges are available in the form of a tantalum loose linings or with the Ultra-Metal tantalum diffusion surface on select flange styles. Due to the cost and limited mechanical properties of tantalum, solid tantalum socket weld flanges are rarely used. 

Contact our engineers to learn if tantalum socket weld flanges are right for your application.

Resources: Tantalum Torque Spec, Flange Dimensions, Flange Bolting Chart

Flange Types Available: Blind Flanges, Lap Joint Flanges, Slip On Flanges, Socket Weld Flanges, Threaded Flanges, Weld Neck Flanges

Tantalum Grades, Specifications and Chemistry

Tantalum (Commercially Pure)

Commercially pure tantalum metal is 99.95% pure tantalum has some o the best corrosion resistant properties of any metal. While its corrosion resistance is exceptional, it is relatively soft and mechanically similar in strength to copper.

Tantalum Specifications: UNS R05200, ASTM B521, B708

Tantalum 2.5% Tungsten (Ta-2.5W)

This grade of tantalum alloyed with 2.5% tungsten provided better overall strength while maintaining its exception corrosion resistant properties. For tantalum fastener applications this is usually preferred.

Tantalum 2.5% Tungsten Specifications: UNS R05252, ASTM B521, B708

Physical Properties

• Density 16.6 g/cc
• Melting Point 3290 K, 2996°C, 5462°F
• Boiling Point 5731 K, 6100°C, 9856°F
• Coefficient of Thermal Expansion (20°C) 6.5 x 10(-6) / °C
• Electrical Resistivity (20°C) 13.5 microhms-cm
• Electrical Conductivity 13% IACS
• Specific Heat .036 cal/g/°C
• Thermal Conductivity .13 cal/cm(2)/cm°C/sec

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Tantalum Tensile Data

Tantalum Iso-Corrosion Curves

Tantalum Corrosion Resistance Table

Socket Weld Flange Features & Benefits

Similar to a slip on flange, an tantalum socket weld flange has an added shoulder inside the bore hole. The socket weld flange is designed so that a pipe can be inserted into the socket of the flange until it hits the shoulder of the socket. The pipe is then backed away from the shoulder approximately 1/16 inches before being welded to the flange hub. This internal weld provides this type of flange added strength. In addition, by grinding the internal weld smooth, turbulence and flow restriction are minimized. Tantalum socket weld flanges are most commonly used on small diameter applications (1/2" through 4") and high pressure piping systems.

Socket Weld Flange Benefits

• Best for small size, high pressure applications
• Static strength equal to a slip on flange yet boasts a fatigue strength 1.5 times that of the slip on design
• Employs both a backside hub weld and an internal shoulder weld for increased strength
• Socket weld flanges delivers a lower risk of leakage than threaded flanges
• Socket weld pipes do not have to be beveled for weld preparation
• Butt-welded joints are easily fitted and no special machining

Socket Weld Flange Disadvantages

• The expansion gap and internal crevices left in socket welded systems can promote crevice corrosion.
• Socket weld flanges have two welds which makes them stronger yet more labor intensive to install. Due to the increased welding, it has become the practice to weld only at the hub of the flange, which is not recommended.

Installation Tips
The socket weld pipe fittings should allow for expansion gap of 1/16 inch (1.6 mm) between pipe and the shoulder of the socket.