Forming Mandrils for elbow forming machine 1. Mandril is for Elbow Forming Machine. 2. Materials of mandrels: 2520,2530,2535,M17 3. Working element: The mandril will welding with a steel rod,and put it into Elbow Making Machine,via the heating induction by Intermediate Frequency Power, raw pipe will be pushed forward to front by hydraulic force ,and finish a elbow forming through the mandril.