Buttweld elbows are typically joined to the pipes through a butt welding process. This involves welding the elbow directly to the end of the pipes, creating a smooth, continuous connection.

Buttweld elbows are available in different angles to suit various piping system requirements. The most common angles are 90 degrees, 45 degrees, and 180 degrees.
A 90-degree elbow is used for a sharp turn, a 45-degree elbow provides a more gradual turn, and a 180-degree elbow reverses the direction of the pipe.

Buttweld elbows can be made from various materials, including carbon steel, stainless steel, alloy steel, and other materials depending on the requirements of the application.

They come in different sizes to accommodate various pipe diameters. The size is specified by the nominal pipe size (NPS) and the schedule (wall thickness).

Buttweld elbows find application in a wide range of industries, including oil and gas, petrochemical, chemical processing, power generation, water treatment, and more.
They are used to navigate around obstacles, change the direction of the pipeline, and ensure a smooth flow of fluids or gasses.

The two primary types of buttweld elbows are short radius and long radius elbows. Short radius elbows have a tighter bend radius, while long radius elbows have a larger bend radius, providing a more gradual turn.

ASTM A234 / A234M:

This standard covers wrought carbon and alloy steel buttweld fittings of seamless and welded construction. It includes 90-degree elbows among other fittings.
Common grades within ASTM A234 include WPB (carbon steel), WPC, WP11, WP22, WP91 (alloy steel), and others.

ASTM A403 / A403M:

This standard covers the standard specification for wrought austenitic stainless steel piping fittings. It includes 90-degree elbows made of stainless steel.
Common grades within ASTM A403 include WP304, WP304L, WP316, WP316L, and others.