Shevtsov S. Improvement of production technology of balloons on the basis of a combination of rotational spinning by a friction tool with bottom upsetting

Dissertation for the candidate of technical science degree, specialty 05.03.05 – Processes and Machines of plastic working. Donbass State Engineering Academy, Kramatorsk, 2018. The dissertation is directed on the solution of the actual scientific and technical task of improving the technological processes of manufacturing bottoms of balloons on the basis of combining the spinning and upsetting of spherical bottoms by a friction tool, which ensure the receipt of high-quality hollow products with high continuity of a bottom wall. The simulation of the processes of spinning and upsetting of spherical bottoms carried out by of finite elements method, which made it possible to establish an effective geometry of the processed workpieces, the temperature of the heating, the size of the feed and the degree of bottom upsetting. The methodology and recommendations for designing of technological pro-cesses for spinning and upsetting the bottoms, which consist in determining the thickness of workpiece wall before deformation, the heating temperature of the workpieces, the determination of the feed magnitude and the degree of upsetting the spherical bottom, is developed. The received recommendations are confirmed in the production conditions. The spinning and upsetting of spherical bottoms should be made from pipes with a relative wall thickness (D / s) in the range of 15 ... 20, the homo-heating temperature should be 0,8, the relative feed workpiece to the tool 0,925, and the degree of upsetting of the bottom 15 ... 20 %. Approbation of the obtained relations in the production conditions confirmed the received recommendations on the modification of spherical bottoms in the process of spinning and upsetting by friction tool. According to the results of the research, a new technology of rotational spinning and upsetting of spherical bottoms by friction tool was introduced. As a result, the gap was reduced by 20 ... 30% and the mechanical properties of the bottom wall were increased by 9 ... 14%. The solutions established in the work have expanded the technological capabilities of the rotational spinning of the bottoms and increased their quality.