|GROSMAN Franciszek||Silesian University of Technology|
|Spoluautoři TKOCZ Marek|
It has been scientifically and practically proved that severe plastic deformation of a workpiece can be caused by induction of cyclic changes of the strain path during metal forming operations. Considerable grain refinement and resulting improvement of functional properties of a product can be obtained this way. Reduction of the required load is possible as well. There are two different loading combinations that can be used in forging practise to achieve the effect of cyclic changes of the strain path: simultaneous compression and oscillatory torsion of a die and compression coupled with transverse, reciprocating motion of a die. Application of this additional die motion causes torque (or force) that acts in the orthogonal direction to the compression force. This force induces additional shear stress in a workpiece. Both loading combinations can find the practical application. The first one would be used to produce round-shaped forgings (e.g. wheels) while the latter would be more advantageous for manufacturing of square or rectangular forgings with ribs, bosses and recesses. Based on the results of numerical simulations, the possible benefits and drawbacks coming from application of additional motion of a die during closed-die forging of the selected aircraft part are discussed in the paper.