Evaluation of the measurement of metal flow and strain distribution in bulk metal forming

A measuring method, using rings of screw threads is proposed in order to solve the difficulties associated with measuring the strain and flow distributions during die forging processes. This method does not use a substitute material to measure the magnitude of the three-dimensional plastic deformation and it can therefore be used in quantitative analysis. Using the proposed method, the strain and four flow lines of typical sections were measured and analysed during the deformation of a coupled model. A distribution rule for the stress-strain relationship is presented. The proposed method is shown to be able to measure and analyse the metal flow during die forging. It can be used to study material flow and to predict strain distribution in general bulk metal forming processes such as extrusion.