Butt-Weld Elbow 90°

A butt-weld 90° elbow changes the flow direction at a right angle in a welded pipeline. Its ends are prepared to the same OD and wall thickness as the pipe it joins and are butt-welded to the pipe. Per ASME B16.9, it is available in long radius (LR — centerline radius 1.5 times the nominal size) and short radius (SR — equal to the nominal size) versions.

It is used in process and utility lines at chemical and food processing plants, in ship and shipyard piping, in the stainless steel lines of fire suppression systems, and in the large-bore suction and return lines of hydraulic power units.

• A long-radius elbow gives lower pressure loss; short radius should be chosen only where space is limited.
• The elbow wall thickness (Schedule) must be the same as the pipe it joins; a different wall thickness creates a step at the weld bevel.
• Bevel angle and root gap are prepared according to the welding process to be used.

Installation note: Check alignment before welding. On stainless steel lines, back purging with a root shielding gas to prevent oxidation of the inner surface, post-weld surface cleaning and visual inspection are recommended.