About Buttweld Pipe Fittings
Buttweld fittings (also know as welded pipe fittings) in carbon steel and stainless steel are the joining components that make possible the assembly of valves, pipes and equipment onto the piping system. Butt welded fittings compliment pipe flanges in any piping system and allows;
- Change direction of flow in a piping system
- Connect or joint pipes and equipment
- Provide branches, access and takeoffs for auxiliary equipment
Manufacturing standards are governed under ANSI/ASME B 16.9. Butt weld is to connect pipes and fittings ends by butt welding process. Also known by welded pipe fittings. It has ends in beveled or plain, dimensions normally from 3/4” to 24”. Unlike the socket weld fittings sizes below NPS 2”, butt weld fittings size can reach to a specific range, you will find that the butt weld fittings range in size from 1/2” to 72”. They are manufactured according to ASME B16.9; material in carbon, alloy and stainless steel. Butt-Weld Fittings are available in variety of kinds such as tees, caps, elbows, reducers and outlets. These fittings are the most common type of welded pipe fitting and are specified by nominal pipe size and pipe schedule. 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.
There are many different types and shapes in the market.
- There are different parameters to be considered before purchasing and that is the size of the pipe fittings in diameter, thickness of the wall to be according to the pressure in the pipes, materials, shape and many others.
- Buttweld fittings use seamless or welded pipe as the starting material and are forged (through multiple process) to get the shape of elbows, tees and reducers etc. Just as the pipe is sold from Schedule 10 to Schedule 160, butt weld pipe fittings are sold the same way. Welded butt weld fittings are more common in stainless steel due to cost advantage. Sch 10 fittings are also more common in stainless steel butt weld fitting. A common example using welded pipe fitting is a pipe reduced by concentric reducer, welded to a weld neck flange and connected to an equipment.
- Other types of fittings can be threaded or socket welded.
Standards and Specifications for Butt Weld Pipe Fittings
|Standard||Grade and Specification|
|ASME||ANSI B16.9, ANSI B16.28, MSS-SP-43|
|DIN||DIN2605, DIN2615, DIN2616, DIN2617, DIN28011|
|ASTM A403 – ASME SA403||Standard Specification for Wrought Austenitic Stainless Steel Piping Fittings|
|ASME B16.9||Factory-Made Wrought Fittings Buttwelding|
|ASME B16.25||Buttwelding Ends|
|ASME B16.28||Wrought Steel Short Radius Elbows and Buttwelding Returns|
|MSS SP-43||Wrought and Fabricated Butt-Welding Fittings for Low Pressure, Corrosion Resistant Applications|
Materials and Grades for Butt Weld Pipe Fittings
|Carbon Steel||WPB, WPC, WPL6|
|Chrome Moly||WP5, WP9, WP11, WP12, WP22|
|Stainless Steel||304/304L, 316/316L, 304H, 316H, 309, 310S, 317L, 321/321H, 347/347H, 904L, DUPLEX 2205 / SUPER DUPLEX 2507|
|High Yield Carbon Steel||WPHY42, WPHY52, WPHY65|
|Nickel Alloys||Alloy 20, 200, 201, 400, 600, 625, 800H/HT, 825, 254SMO, AL6XN, C276, C22, B3, HAST-X|
|Standard Materials||Carbon, Stainless, Chrome Moly, High Yield, Low Temperature, Aluminum|
|Types||Elbows, Tees, Reducers, Caps, Stub Ends, Crosses, Laterals, Olets, Return Bends|
|Sizes||Standard 1/2″ to 48″ (special order larger O.D. fittings)|
|Wall Sizes||Schedule 20 thru XXH, and Special Wall Sizes|
|Specialty Items||3D & 5D Bends, Galvanizing, 100% X-ray Testing|
Butt Weld Dimensions
- Butt Welded Pipe Fittings Dimensions refer to pipe size standards ANSI B36.10 and B36.19.
- Diameter range: 1″, 2″, 3″, 4″, 6″, 8″ and maximum 72″.
- Thickness range: Schedule 10, Schedule 40, Schedule 80, XS, XXS and SCH 160
- In the case of involving mounting dimensions of butt welded fittings, this will include the diameter in the NPS and the thickness in the schedule.
Types of Butt Weld Pipe Fittings
- Pipe Elbows – Steel elbow is used to be installed between two lengths of pipe or tube allowing a change of direction, usually these carbon steel elbows distinguished by connection ends.
- Pipe Bending – Pipe bend can be made of variety materials, like carbon steel, alloy steel, stainless steel, low temperature steel or high-performance steel, etc.
- Pipe Tees – We can provide seamless tube tees and welding tube tees, which can also be divided into straight tees and reducing tees. Usually, the pipe tees have the same inlet and outlet sizes.
- Pipe Cross – A pipe fitting, having four openings in the same place, at right angles to each other. A pipe cross is a kind of pipe fitting. It is used in the place where four pipes meet together. The pipe cross may have one inlet and three outlets, or three inlets and one outlet.
- End Caps – End Cap, Carbon Steel cap, Stainless Steel Caps, ANSI, ISO, JIS and DIN Standards, Measures 1/2 to 56 Inches. Based on different materials, pipe caps include carbon steel cap, stainless steel cap, and alloy steel cap etc.
- Pipe Reducer – Pipe reducer are tube fittings that are widely used in a number of industries in order to providing greatest connection flexibility in connecting fractional tubes in various installations.
- Stub End – Stub Ends are fittings used in place of welded flanges where rotating back up flanges are desired. They are also called Lap Joints and Vanstone Flared Laps. A rotating back up flange seats itself against the back surface of the Stub End.
- Coupling Fittings – Coupling fittings are used for fluid conduits in which each end portion of two tubes to be connected is provided with a swaged-on adapter carrying the necessary means to connect or disconnect the tubes without disturbing the swaged-on adapter.
Advantages of Butt Weld Pipe Fittings
- Various turning options and easy to weld.
- Butt weld saves more cost than socket weld or threaded.
- Allow thin thickness as SCH 10 or SCH 10S.
- Compatible with different sizes from 1/4 inch to 24 inch and up to 72 inch.
- Continuous metal structure increases the strength of the piping system.
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, less turbulence.
- The welded connection would help to get more robust connection.
- Continuous structure of metal would add to the strength of the piping system.
- When butt weld fittings would be matched with the appropriate pipe schedules, they would help to offer a seamless flow inside the pipe.
- It provides the option of various turn radius by using Long Radius, Short Radius, or 3R elbows.
- Found to be cost effective compared to the socket weld or threaded counterparts.
- These fittings would be available in Schedule 10, thus allowing for a thinner wall option.
- These fittings have been found to be more common in the configuration of Schedule 10 and Schedule 40.
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.
Applications of Butt Weld Pipe Fittings
Fittings are used wherever liquids, gases, chemicals and other fluids are created, processed, transported, or used. Range of industries is very wide, as shown below:
- Energy related – Oil and gas industries, including upstream (exploration and production), midstream (transportation by ships, pipeline, rail, trucks; storage and wholesale) and downstream (refining into fuels or chemicals; marketing and distribution). Power plants using fossil or nuclear fuels. Geothermal energy for harnessing heat from the earth.
- Food and beverage production – From basic ingredients to elaborate desserts. From milk, to juices and other beverages. Cold chain to keep produce fresh, drinks and frozen foods at a set temperature. Desalination plants to transform seawater into drinking water for arid areas and various tropical islands.
- Pharmaceuticals and biotech production – Medicines and vaccines that treat illnesses and help restore bodies and minds to their top conditions.
- Semiconductor manufacturing – Microchips that go into all electronics, including smartphones, tablets, computers, television sets, telecom networks.
- Pulp and paper production – Newsprint, glossy paper, cardboard boxes, books, writing paper.
- Production of construction materials and plastics – From roofing materials, to glassmaking for windows, to copper wiring for transporting electricity, and various plastics throughout houses and office buildings.
How are Buttweld Pipe Fittings Manufactured?
Key steps in manufacturing process are as follows:
- Planning: based on fitting specifics and client requirements; includes creating part identification in manufacturing system.
- Selection of raw material: metal; plate or pipe.
- Welding: for fittings that are not simple elbows, returns, bends, reducers or caps.
- Inspection and tests: according to standards and client requirements.
- Coating (if required).
- Preparation of documentation.