Butt weld Fittings FAQs by Sandco Metal Industries
What is a butt weld pipe fitting?
1) 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.
2) 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.
3) Other types of fittings can be threaded or socket welded.
What are advantages of butt welding over flanges?
1) Flanges connect pipes by bolting them together, whereas butt weld fittings connect pipes by welding them together.
2) Depending on size, butt weld fittings require 10% to 75% less material than a flanged connection, which means lower material cost and lower weight.
3) Welded construction permits greater freedom in designing a layout; this system uses less space, is more compact, and has greater strength.
4) Butt weld fittings provide optimum flow characteristics, without pockets or sharp corners, creating less frictional resistance, no pressure loss, less turbulence
What is a seamless butt weld fitting?
1) 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.
2) A seamless fitting has no welded parts by itself, a characteristic demanded in some critical applications.
3) By comparison, a regular butt weld fitting has one, two or more welds, depending on dimension, shape and manufacturing method.
4) No weld means less risk of weld yield and porosities.
What does 45 SR or 90 LR mean for pipe fittings?
1) 45 and 90 refer to angles for changing direction of pipe flows: 45 degrees or 90 degrees. Most elbows are 45˚ or 90˚.
2) SR means Short Radius; LR means Long Radius. Centerline radius of long radius (LR) elbows is smoother than of short radius (SR).
3) In SR fittings, radius equals nominal diameter size. A 6 inch pipe will have a 6 inch radius center-to-end, giving it a sharp curve.
4) In LR fittings, radius equals 1.5x nominal diameter size. A 6 inch pipe will have a 9 inch centerline radius, for a smoother curve than SR.
What does 3D or 6D mean for pipe fittings?
1) Larger numbers have smoother curves.
2) Centerline radius is calculated based on diameter and number that precedes it. For example, a 10″ 6D has a 60″ centerline radius.
3) Smoother curves are often used for applications with higher pressure, abrasion or corrosion.
What is a lateral pipe fitting?
1) A lateral separates one line into two; the second line branches at a 45˚ angle.
Why do manufacturers offer such a large variety of metals and materials?
1) Pipes and fittings are used in many applications and many industries that have widely different operating conditions.
2) To reach best performance (resistance to various types of corrosive fluids, operating temperature …) at acceptable costs, many metals have found unique niche applications in fittings.
