PVC elbow in pipe system, elbow is the pipe that changes the direction of pipeline. According to the angle, there are 45 degrees and 90 degrees 180 degrees which are most commonly used, and other abnormal angle elbows such as 60 degrees are also included according to the needs of the project. Elbows are made of cast iron, stainless steel, alloy steel, calcinable cast iron, carbon steel, non-ferrous metals and plastics. Connection with the pipe are: direct welding (the most commonly used way) flange connection, hot melt connection, electric melt connection, threaded connection and socket connection. According to the production technology, it can be divided into: welding elbow, stamping elbow, pushing elbow, casting elbow and so on. Other names: 90 degrees elbow, right angle bend, love and bend. National Standard Process Flow of Sinopec Standard Pipe Fittings Implementation Standard.