Assessment of the deformation of the billet material in the direct expression by the roll stamping method

Abstract

Mikhalevich V., Matviychuk V., Kolisnyk M. Assessment of the deformation of the billet material in the direct expression by the roll stamping method

The article presents the results of the development and research of the technological scheme of direct extrusion by the method of stamping by rolling with a conical roll for obtaining complex profile blanks. Since the technological possibilities depend on the deformability of the material, the stress-strain state of the workpieces was analyzed using the mesh method, hardness measurement, and microstructural analysis. The main result of the analysis was the construction of the paths of deformation of the parts of the material of the workpieces in the coordinates "intensity of deformations - an indicator of the stressed state". Zones of workpieces that are deformed under the conditions of a "hard" stress state have been identified, so it is precisely for these zones that an assessment of the deformability of metals has been carried out. To assess the deformability of the material of the workpieces, a damage accumulation model was built based on V.А. Ogorodnikov's criteria and a certain technique for constructing the approximation of the limit deformation curve. From the results of the study of the deformability of the workpiece material, it follows that, compared to the linear principle of accumulation of damage, the calculation based on the model based on V.A. Ogorodnikov's criteria reduces the calculated value of the ultimate deformation. At the same time, setting the non-linearity parameter of damage accumulation to values  that satisfy the condition leads to an increase in the calculated value of the limit strain compared to the linear principle of damage accumulation.