Butt welding pipe fittings manufactured in accordance with ASME B16.9 may be furnished with three types of welding ends depending on its nominal wall thickness, t:
When 5 mm [0.19″]≤ t ≤ 22 mm [0.88″] for carbon steel or ferritic alloy steel, or 3 mm [0.12″]≤ t ≤ 22 mm [0.88″] for austenitic steel or nonferrous alloys, plain bevel ends shall be furnished as shown in Illustration A.
When t is more than 22 mm [0.88″], compound bevel ends shall be furnished as shown in Illustration B.
Moreover, unless otherwise specified by the purchaser, transitions from the welding bevel to the outside surface of the fitting and from the root face to the inside surface of the fitting shall be lying within the maximum envelope, which is usually at the manufacturer’s option. Both A and A’ zones in Illustration A and B are known as the transition contours.
|ASME B16.9 Butt Welding Fittings|
|Elbow L/R||Reducing Elbow||Return L/R|
|Elbow S/R||Return S/R||3D Elbow|
|Tee & Cross||Reducing Tee||Reducing Cross|
|End Bevel||Tolerance||Wall Thickness|