Effects of Rigid Mandrel and Lubrication on the Process of Elbow Parts by Cold Push-Bending

The push-bending process to prepare SS304 elbow was simulated with Dynaform software. We firstly investigated the effects of rigid mandrels on the curvature variation of the intrados, extrados and the ring direction of SS304 elbow. Then, we discussed that the friction coefficient between die and tube blank played an important role in thickness distribution, and we studied the face reflection result and ring direction thickness distribution for the different section lines. Subsequently, the practical push-bending was performed based on the simulation results with the aid of special lubrication coatings of lower friction coefficient. It was obviously indicated that the simulation results agreed well with the experimental ones in geometry size and wall thickness distribution. The results indicated that the qualified SS304 elbow could be obtained by using the extended mandrel and the lubricant with lower friction coefficient.