The role of tool geometry and process parameters during fly shearing in hot rolling of steel

Sheet metal shearing takes place immediately after hot rolling of steel. Due to the extreme operating conditions, flying shear blades suffer from severe wear and need frequent repair, significantly increasing the maintenance costs for steel producers. In order to optimise the shearing process and increase the tool lifetime, a finite element model was applied for performing a systematic variation of the blade geometry and process parameters. In the model, friction is taken into account by implementing a hybrid friction equation, which is suitable for the simulation of metal forming processes. Tool geometry and process parameters such as the vertical overlapping between the two shearing blades were varied in the simulation, in order to identify optimum process parameters. The results obtained show in particular that the variation of the vertical overlapping between both blades has a limited influence on the maximum calculated stresses, leading to the assumption that no significant changes in tool wear may be achieved by modifying it. On the other hand, it was found that higher cutting edge radii lead to significantly lower stresses for both flying shear blades, thus suggesting the possibility of decreasing tool wear through increasing values of the cutting edge radius. © (2014) Trans Tech Publications, Switzerland.