Stainless Steel Threaded Fittings: Types and Applications

Threaded fittings are the parts used to join, turn, reduce or close pipelines without welding. Because they are easy to install and can be removed when needed, they are widely used in industrial plants on water, air and auxiliary media lines. In this article we group stainless steel threaded fittings by function and explain what each one does.

When Are Threaded Connections Preferred?

Threaded connections offer fast installation without welding equipment, easy removal during maintenance and a practical solution on small-diameter lines. On the other hand, thread roots and joint gaps can trap product residue, so hygienic process lines in direct contact with the product generally use clamp, union or welded hygienic connections. Threaded fittings are the typical choice for utility, service and auxiliary lines.

Changing Direction and Branching

• Threaded elbow: Turns the line by 90°. Both ends have female threads.
• Street elbow: One end has a female thread and the other a male thread, so it changes direction without an extra nipple.
• Threaded equal tee: Takes a third branch of the same size off the line.
• Cross: Joins the line in four directions at the same size.

Joining: Sockets and Nipples

• Socket: A female-threaded part that joins two male-threaded pipes end to end.
• Double nipple: Male threads on both ends; connects two female-threaded parts.
• Hexagon double nipple: The hexagon in the middle makes it easy to tighten with a spanner.
• Weld nipple: Threaded at one end and plain for welding at the other; provides the transition from a welded line to a threaded connection.
• Hose nipple: Connects a threaded line to a hose.

Detachable Connections: Unions

Unions allow two parts to be separated without dismantling the whole line. Placing unions before and after equipment that needs maintenance, such as valves, pumps or strainers, makes that equipment easy to remove.

• Conical union: Gasketless design; sealing is achieved by conical seating surfaces.
• MF union: A gasketless union with a male thread on one end and a female thread on the other.

Reducing and Closing

• Hexagon bushing: Larger male thread outside, smaller female thread inside; joins threaded connections of different sizes.
• Threaded cap: A female-threaded cap with a hexagon body that closes a male-threaded pipe end.
• Blind plug: A male-threaded plug with a hexagon head that closes female-threaded openings.
• Half socket: Welded onto a pipe or tank surface to create a threaded connection port; used for sensor, valve or drain connections.

Choosing the Right Threaded Fitting

• Thread size and type: The thread size (from 1/8" to 4") and thread standard of the parts must match. State the thread standard used on your line when ordering.
• Male or female: Whether the two ends to be joined are male or female determines the choice between a socket, a nipple or a street elbow.
• Maintenance needs: Using unions next to equipment that is removed often shortens maintenance time.
• Material: Our threaded fittings are mainly made of AISI 304 stainless steel. The material of each product is given on its product page.
• Sealing: Use a thread sealant suitable for the application and do not over-tighten the parts during installation.

Technical Information and Quotes

The dimension tables and technical drawings of all threaded fittings are available on the related product pages. You can browse our other products, including welded fittings and flanges, in the Industrial Products category. For valves used on threaded lines, see our ball valve and check valve guides. To request a quote, get in touch with us.