In the process of production, elbow can be effectively divided into long radius thick wall elbow and short radius thick wall elbow. A long radius thick wall elbow has a radius of curvature equal to 1.5 times the outer diameter of the pipe, i.e., R=1.5D. A short radius thick wall elbow has a radius

There are mainly the following six methods of pipe bending in the pipe bending factory　　 Stamping method: Use a tapered core on the punch to expand the pipe end to the required size and shape.　　Rolling wheel method: Put a core in the tube, and push the outer circumference with a roller for round edg