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
• Weld neck flange features and benefits

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

Tantalum weld neck 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 weld neck 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 weld neck 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 weld neck flanges are rarely used. 

Contact our engineers to learn if tantalum weld neck 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

Tantalum Weld Neck Flange Features & Benefits

Tantalum weld neck flanges are best for hazardous, high pressure applications. Weld neck flanges are easily identified by their long tapered neck. The inside of the flange is bored to match the inside diameter of the pipe in order to ensure there is no restriction in flow and also to prevent turbulence at the joint. The tapered neck provides thicker metal at the flange joint, while the neck narrows down gradually to meet the pipe where it is butt welded to the pipe. This design helps to transfer stress from the flange to the pipe, as well as diminish stress concentration at the base of the flange connection.

Tantalum weld neck flanges are ideal for critical applications involving high pressure, sub-zero and elevated temperatures, as well as in conditions where fluctuations cause pipe expansion/contraction.

Key Feature: Ideal for high presure applications.

Weld Neck Flange Advantages

• Ability to withstand high pressure – since pipe is welded to the neck of the flange, stress is transferred to the pipe.
• The beveled end that, when connected to a pipe, creates a trough for a strong weld.
• Most versatile flange in the ASME stable of flanges.

Weld Neck Flange Disadvantages

• More advanced welding skill is needed for installation. The inside weld must be smooth to reduce friction and the outside weld must meet code criteria.

Uses

• Severe conditions that include high-pressure, high-cyclic and hazardous fluid applications.
• Fitting-to-fitting fabrication where the flange is welded directly to a fitting, such as an elbow, without the need for a short piece of pipe, as would be required with a slip-on flange.