Butt Weld Fittings

Butt weld fittings get their name from the method for which they attached to a piping system.  Each end of a butt weld fitting is beveled, and it is attached by butting the fitting up to the adjoining pipe and welding along the bevel.  This connection is both stronger and smoother than threaded or socket weld connections, making butt weld fittings the preferred product for critical applications.

A butt weld pipe fitting is designed to be welded on site at its end(s) to connect pipe(s) together and allow change in direction or pipe diameter, or branching or ending. This fitting then becomes part of a system for transporting fluids (oil, gas, steam, chemicals, …) in a safe and efficient manner, over short or long distances. Other types of fittings can be threaded or socket welded.

What are advantages of butt welding over Flanges?

Flanges connect pipes by bolting them together, whereas butt weld fittings connect pipes by welding them together. Depending on size, butt weld fittings require 10% to 75% less material than a flanged connection, which means lower material cost and lower weight. Welded construction permits greater freedom in designing a layout; this system uses less space, is more compact, and has greater strength. Butt weld fittings provide optimum flow characteristics, without pockets or sharp corners, creating less frictional resistance, no pressure loss and less turbulence.

What is a seamless butt weld fitting?

A seamless butt weld pipe fitting is made directly from a section of seamless pipe material, by applying heat and pressure to transform pipe directly into an elbow or other shape. A seamless fitting has no welded parts by itself, a characteristic demanded in some critical applications. By comparison, a regular butt weld fitting has one, two or more welds, depending on dimension, shape and manufacturing method. No weld means less risk of weld yield and porosities.

Types of Butt Weld Fittings

Tees: Tees are butt weld fittings used to combine or divide process flow, and Reducing Tees additionally allow for butt weld fittings size change.  The run outlets of the tee are the two in-line outlets, and the branch is the third outlet.  The branch outlet is the reducing outlet in a reducing tee.

Butt Weld Fittings

Elbows: An elbow is a butt weld fitting is used to change the direction of flow in a piping system, usually at the 90° or 45° angle. Like a reducing tee, reducing elbows also exist to simultaneously change flow direction and reduce flow diameter.  90 degree elbows are also available in both short radius and long radius patterns, whereas 45 degree elbows are only available as long radius.  

Butt Weld Fittings

Who decides on standards and specifications for butt weld fittings?

Manufacturers of butt weld pipe fittings have to meet specifications and requirements of many organizations, to assure quality, compatibility and performance of their products. Key national and international standards organizations focus on materials and end-user industries, including American Society for Testing and Materials (ASTM), American Society of Mechanical Engineers (ASME), International Organization for Standardization (ISO) & Norway’s NORSOK.

Some international organizations also focus on quality standards across all industries, such as International Organization for Standardization (ISO). Large industrial end-users also have their own programs to certify individual manufacturing plants as meeting their criteria to be listed on their Approved Manufacturers List (AML). All these certifications and approvals are valid for a specific period, and must be renewed regularly.

About Us

MSI Supply is a Houston, TX based full-line distributor of pipe, valves, fittings, flanges, stud bolts, gaskets, and fasteners, serving price-conscious customers who desire quick deliveries and consolidation of their material needs. With a large inventory of carbon and stainless pipe, cast and forged steel valves, tubing, and the thousands of fittings and fasteners required to put it all together, MSI can meet the needs of virtually any piping, fastener, or instrumentation project.

Also MSI is a full-line distributor of gate valves, globe valves, and check valves, with a large portfolio of: carbon steel, stainless steel, and exotic alloy. End connections for each gate valve, globe valve, and check valve include: flanged, threaded, and socket weld. With sizes ranging from 1/4” to 36", and pressure classes ranging from 150# - 2500#, MSI can supply the gate valves, globe valves, and check valves to meet the requirements of virtually any piping project.