What is Buttweld Pipe Fittings?

Buttweld pipe fittings are used to connect and join pipes with a welded seam. A buttweld fitting is a weldable pipe fitting that allows for change of direction of flow, to branch off, reduce pipe size or attach auxiliary equipment. Forged Steel buttweld fittings are manufactured in accordance with ANSI / ASME B16. 9.

Buttweld pipe fittings are typically made of the same material as the pipes that they are used to connect, and are welded onto the end of the pipe using a butt-welding process.

Buttweld pipe fittings come in a variety of shapes and sizes, including elbows, tees, reducers, caps, and stub ends. Elbows are used to change the direction of the flow of fluid or gas, while tees are used to split the flow into two or more directions. Reducers are used to connect pipes of different sizes, while caps are used to seal the end of a pipe. Stub ends are similar to caps, but are used in conjunction with flanges to make it easier to connect and disconnect sections of pipe.

Buttweld pipe fittings are commonly used in a variety of industries, including oil and gas, petrochemical, and power generation. They offer a strong and reliable connection that can withstand high pressures and temperatures, making them ideal for use in harsh environments.

When selecting buttweld pipe fittings, it is important to consider factors such as the diameter and thickness of the pipes being connected, as well as the requirements of the application in which they will be used. Proper installation and maintenance of buttweld pipe fittings is also important to ensure their performance and longevity.

Buttweld pipe fitting are devices that influence the characteristics of the flow in the system. The Buttweld Pipe Fittings are produced via the hot or cold rolling process. Here they are bent or molded in their correct shape. The versatile Butt Weld Fittings are bevelled at each end of the fitting to match similar ends of a pipe. The fitting have excellent strength and good tolerances in different conditions.

buttweld fittings types

What are the different Buttweld Pipe Fittings?

Buttweld fittings are available in multiple shapes (elbows, tees, reducers, crosses, caps, stub ends), material grades (carbon, high-yield carbon, low-alloy, stainless, duplex, and nickel alloys), and dimensions (2 to 24 inches in seamless execution, and welded for larger pipe sizes).

What is the difference between Buttweld and socket weld?

A socket weld fitting fits over the outside of the pipe it is being welded to whereas a butt weld is the welding of two of the same sized diameters joined end to end. A socket weld fitting fits over the outside of the pipe it is being welded to. No beveling is needed as the socket weld forms a fillet weld.

What is the standard Buttweld end?

The ends of all buttweld fittings are bevelled, exceeding wall thickness 4 mm for austenitic stainless steel, or 5 mm for ferritic stainless steel. The shape of the bevel depending upon the actual wall thickness.

Buttweld Carbon Steel and Stainless Steel Pipe Fittings

Buttweld pipe fittings comprises of long radius elbow, concentric reducer, eccentric reducers and Tees etc. Butt weld stainless steel and carbon steel fittings are an important part of industrial piping system to change direction, branch off or to mechanically join equipment to the system. Buttweld fittings are sold in nominal pipe sizes with specified pipe schedule. BW fitting’s dimensions and tolerances are defined as per ASME standard B16.9.

Butt welded Pipe fittings such as carbon steel and stainless steel offer many advantages compared to threaded and socketweld fittings. The later are only available up to 4-inch nominal size whereas butt weld fittings are available in sizes from ½” to 72”. Some of the benefits of weld fittings are;

  • Welded connection offers more robust connection
  • Continuous metal structure adds to the strength of the piping system
  • Butt-weld fittings with matching pipe schedules, offers seamless flow inside the pipe. A full penetration weld and properly fitted LR 90 Elbow, Reducer, Concentric reducer etc. offers gradual transition via welded pipe fitting.

 All buttweld pipe fittings have beveled ends as per ASME B16.25 standard. This helps create full penetration weld without any extra preparation needed for the butt weld fitting.

Butt weld pipe fittings are most commonly available in carbon steel, stainless steel, nickel alloy, aluminum and high yield material. High yield butt weld carbon steel pipe fittings are available in A234-WPB, A234-WPC, A420-WPL6, Y-52, Y-60, Y-65, Y-70.  All WPL6 pipe fittings are annealed and are NACE MR0157 and NACE MR0103 compatible.

Trupply is one of the largest distributors of pipe flanges and fittings. We handle hundreds of requests every day. Some of the common misconceptions people have are;

  • They call BW fittings in A105 material: Most common carbon steel buttweld fitting material is A234WPB. It is equivalent to A105 flanges, however there is no such thing as A105 or A106 butt weld fitting
  • They request “Normalized” butt weld fittings: This is also a misconception since flanges are available in A105 and A105 N, where N stands for normalized. However, there is no such thing as A234WPBN. Some manufactures normalize their butt weld fittings as a standard procedure and such request require checking individual MTRs to verify if normalized heat treating process was done. Customer needing “normalized” butt weld fittings should request WPL6 fittings which are high yield and are normalized as a standard procedure
  • They forget to mention pipe schedule: Buttweld fittings are sold as per pipe size but pipe schedule must be specified to match the ID of the fitting to the ID of the pipe. If no schedule is mentioned, we will assume a standard wall is requested.
  • Differentiate between SCH 40 and True Schedule 40: Pipe fittings 12 inch or larger require specifying if fitting is standard wall (most commonly referred to sch 40) or a true schedule 40 is required. This is needed since schedule 40 do NOT correspond to standard wall for pipe sizes 12” and bigger. A true sch 40 will be thicker than standard wall for pipe fittings 12” or bigger.
  • Stainless Steel butt weld pipe fittings are available in schedule 10s: Customer should specify if they need standard wall (sch 40s) or a thinner wall sch 10s stainless steel butt weld fitting. See pipe chart to clarify how the wall thickness for stainless steel pipes correlated to different pipe schedules.
  • They forget to mention welded or seamless butt weld fitting: Butt weld fittings are available in both welded and seamless configuration. A seamless butt weld carbon steel or stainless steel fitting is made of seamless pipe and is generally more expenses. Seamless pipe fitting is NOT common in sizes bigger than 12”. Welded pipe fittings are made of ERW welded carbon steel or stainless steel pipe. They are available in sizes ½” to 72” and are more affordable than seamless fittings.

What does Short Radius (SR) or Long Radius (LR) means?

You will often hear SR45 elbow or LR45 elbow. The 45 or 90 refers to the angle of the bend for butt weld fitting to change the direction of flow. A long radius elbow (LR 90 Elbow or LR 45 elbow) will have a pipe bend that will be 1.5 times the size of the pipe. So, a 6 inch LR 90 has bending radius that is 1.5 x nominal pipe size. A short radius elbow (SR45 or SR90) has pipe bend that is equal to the size of fitting so a 6” SR 45 has bending radius that is 6” nominal pipe size.

What is a 3R or 3D elbow pipe fitting?

First, the term 3R or 3D are used synonymously. A 3R butt weld elbow has bending radius that is 3 times the nominal pipe size. A 3R elbow is smoother than SR or LR fitting.

  •  A concentric reducer buttweld fitting is symmetrical: both ends are aligned along the center.
  • An eccentric reducer butt weld fitting is not symmetrical: ends are off center of one another.

Plain End Vs Bevel End Fitting

A plain end fitting is a fitting which is 90 degree perpendicular to the running direction. These ends are very common and don’t have any special finish on them. The bevel end fitting are not perpendicular to the pipe but are bevelled at an angle of 37.5 degrees. These ends are used for creating Steel Buttweld Fittings joints.