304 stainless steel elbow: A pipe fitting used in piping systems to connect two pipes with the same or different nominal bore sizes, allowing the pipeline to make a certain angle turn.

Elbow: A pipe fitting in a piping system that connects two pipes of the same or different nominal diameters, allowing the pipeline to bend at a certain angle.

Elbow classification: Commonly used angles include 45°, 90°, and 180°, with additional non-standard angles like 60° available as per engineering requirements.

Ways to connect pipes include: direct welding (a common method), flange connection, threaded connection, and socket and spigot connection, etc.