RESEARCH OF THE ROLLING PROCESS WITH A SCREW WORKING SURFACE

Abstract

Recently, in Ukraine and in other countries, special attention is paid to the quality and technological heredity of finished products, which receive metal treatment by pressure. One of the important tasks in the production of parts is to ensure the high quality of the working surfaces and improve the physical and mechanical characteristics of the surface layer of their material. One of the most economical and effective ways of solving this problem is to strengthen details by surface plastic deformation (PPE), which allows to more fully realize the potential properties of structural materials in real details of complex structure and in details with stress concentrators. Using the methods of deformability theory, the value of the resource used and its dependence on the parameters of the process of surface plastic deformation is determined at the design stage. It is necessary to have information about the stress-strain state in the deformation cell and the laws of its change, depending on the parameters of the process of surface plastic deformation. The most effective direction for improving the technology of roughing roller is the choice of rational parameters of the geometry of the tool and process technology. Analyzing the obtained results it can be concluded that there is a significant nonmonotonic deformation due to the fact that there is a wave in front of the roller in which there is a stress tension, while under the roller there is a stressful state of comprehensive compression. In addition, when changing the direction of obstruction, the sign of tangential stresses, which contributes to the partial recovery of microcracks and, consequently, to reduce the value of the used resource of plasticity. According to the results of researches, it was established that the optimal mode is treatment, in which a tool with three turns is used and the routing is performed once in two opposite directions. This allows you to increase the hardness of the original workpiece almost twice and get a surface with a minimum roughness. The obtained results show the advantage of nonmonotonic deformation, as in these cases, with the same degree of deformation of the surface layer of the metal, the resource of plasticity in the first case is much smaller.