Experimental and Numerical Investigation of Die Filling and Thickness Distribution for Producing Bended Tubes with Non-Uniform Bending Radius and Diameter in Hydroforming Die with Moveable Bushes

Achieving sharp corners in hydroforming process is difficult or impossible in experimental producer. Also, augmenting pressure for producing sharp corner and filling the die is caused local thinning and fracture in the corners of tubes. Then, the corner of tubes has the less thickness compared with the other parts. In new dies which leads sharpen corners, tube forming contains two phases, bulge and forming. In current paper, a new die for producing bended SS-316L tubes with non-uniform bending radius and diatreme has been offered by considering experimental tests and finite element modelling. Having two movable bushes for producing completely filled steps is one of the merits of new die. Movement of movable bushes can omit the friction between die and bushes while the specimen is feeding. Another advantage of this die is having less forming pressure and non-complicated die structure. In addition, thickness distribution of tubes which was produced in this die is more uniform than the previous dies.