K Abrinia - Engineering Department, College of Engineering, University of Tehran
H.R Farahmand - Engineering Department, College of Engineering, University of Tehran

A process simulation of the reshaping of thick square tubes from round pipes has been presented based on a theoretical analysis developed in this paper. The theoretical work is based on the upper bound theory which is in common use for solving metal forming problems. In order to formulate the theory the deforming zone was divided into two distinct regions; one which was called the free region where the material was not in contact with the rolls and the other the contact region where the material was in contact with the rolls. Formulations defining a moving particle during the material flow were derived. Velocity and strain rate fields were obtained based upon which the upper bound on power was calculated. The process of reshaping or shape rolling of a circular pipe into a square tube under the influence of four identical rolls was simulated. The effect of various process parameters such as the initial geometry of the pipe and the roll speed were investigated. The effect of these parameters on the power dissipated during the process, the thickness of the final product and the corner radius of the final product were studied. Theoretical results obtained from the simulation were compared with the experimental observations made by the authors and excellent agreement between the two was observed.

shape rolling, square section, simulation, upper bound, tube, pipe