In piping systems, elbows are pipe fittings used to change the direction of the pipeline. Commonly available in 45°, 90°, and 180° angles, additional non-standard angles such as 60° elbows are also available based on engineering requirements. Elbow materials include cast iron, stainless steel, alloy steel, malleable cast iron, carbon steel, non-ferrous metals, and plastics.

Ways to connect pipes include direct welding (commonly used), flange connection, hot melt connection, electric melt connection, threaded connection, and socket welding connection, etc. They can be categorized by production process into welded elbows, stamped elbows, expansion elbows, cast elbows, and socket-welded elbows, etc. Other names: 90-degree elbows, right-angle elbows, etc.