Evaluation of Deformability of Material of Preparations in Direct and Reverse Extraction by Rolling Stamping Method

Abstract

The article presents the results of development and research of various technological schemes of the process of stamping by rolling cylindrical and conical rolls to obtain complex profile workpieces. It is shown that the achievement of significant dimensions of the various elements of the workpiece is possible by providing a directed flow of metal by changing the relative position of the roll and the workpiece. The most effective rolling operations are landing, settling, unloading, reverse and direct extrusion. The paper focuses on the analysis of operations of reverse and direct extrusion to obtain complex profile blanks with developed, including thin-walled elements. Since the technological capabilities depend on the deformability of the material, the analysis of the stress-strain state of the workpieces was performed using the method of grids, hardness measurement and microstructural analysis. The main result of the analysis was the construction of ways to deform the particles of the workpiece material in the coordinates "deformation intensity - stress index". Zones of blanks that are deformed in the conditions of "rigid" stress state are established, therefore for these zones the deformability of metals was assessed using the criteria of phenomenological theory. In addition, the assessment of deformability was also performed for areas with the maximum degree of deformation of the material. The manufacture of thin-walled elements of the workpiece, using the operation of reverse extrusion, is accompanied by the appearance of significant contact stresses. To prevent the roll from being pushed out of the workpiece and forming elements with a constant thickness, support rollers should be provided. In the case of direct extrusion, the increase in contact stresses requires the application of additional measures to increase the strength of the tool.