Optimization technique of the matrix channel for twist extrusion

Submicrocrystalline formation condition in billets of metals and their alloys is possible by intensive plastic deformation (IPD) by twist extrusion. Successful implementation of IPD for alloys of different classes can be set at the optimum combination of process parameters. Attempts to implement IPD prismatic billets made of titanium alloys empirically often led to the blanks destruction or inadequate level of fragmentation patterns. The purpose was to develop and test methods of numerical modeling of the stressstrain state of billets during IPD twist extrusion. Developed technology describes the basic steps of the numerical simulation state blanks depending on important parameters such as the geometry of the preform and the amount of back pressure of the screw channel twist law, and others. Its implementation allows to set the operating parameters of the process in which there is a uniform structure throughout the fragmentation amount of timber without destroying it. Determined by the energy required to implement IPD billets depending on their geometry, temperature, geometry of the screw channel and a number of process parameters, can count on the need to strengthen the stem press. The simulation results allow to determine the degree of pre-strain for parts made from deformed screw extrusion billets, depending on their place of scraps given the uneven deformation of the cross section of prismatic billets. On the example of blanks square and rectangular cross-section shows the distribution of the shear and equivalent stresses along the screw channel in different sections. The results of modeling the fields of stress and strain distributions in different sections of the billets are obtained. Thus, modeling method in conjunction with the methods of experimental design and optimization of the objective functions was developed, enables the optimization of operating parameters of IPD pieces of metallic materials in order to obtain submicrocrystalline structure.