End Preparation of ASME B16.9 BW Fittings

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 t is less than 5 mm [0.19″] for carbon steel or ferritic alloy steel and 3 mm [0.12″] for austenitic steel or nonferrous alloys, the fitting shall be furnished with cut square or slightly chamfered ends. It is often called “plain end”.
• 

  Illustration A – the plain bevel end for ASME B16.9 butt welding fittings.

  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.

• 

  Illustration B – the compound bevel end for ASME B16.9 butt welding fittings.

  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.