Mengcun Butt Welded Elbow making way

To make long radius elbow, first to choose suitable pipe. How to give suitable pipe for a elbow,via theoretical calculation, normally rate is 33%-35%. OD 219mm Short radius rate is 50%. After choosing the raw pipe,then to cut pipe to correct length for a elbow. For example: 90 degree elbow, via calculate its curvity,you will get the figure that how long pipe is required.
Pushing elbow via forming machine is a simple producing way : Mandrel is important,mandrel shape is from small outside diameter to big outside diameter. Total pushing process is expanding pipe OD as well as bending. Connect mandrel with mandrel pole by careful welding.
Insert mandrel pole in front of machine to back machine,Elbow machine has support board to maintain mandrel pole does not fall down.
Put cuted raw pipes to the mandrel pole, back clamp will tight the mandrel pole and keep it fixed .Then tight the raw pipe at position of middle pushing board by clamp.Pushing board is driven by hydraulic system,or mechanical system,the system made pipe come to the front of machine and get a forming by mandrel under pushing force.