Study On A Local-heating Rotary Thickening Process Of Disc-like Blanks

Building an environment-friendly and resource-conserving industrial system is the direction of modern manufacturing, among which optimization of the product structure, performance and production using advanced designing and manufacturing methods is very important. In this paper, a new local-heating rotary thickening process was proposed to produce a disc-like part with characteristics of a thin web plate and a thick rim, which is usually used as a flying wheel panel in mobile industry. Compared with the traditional stamping or machining methods, the structural stability and integral performance of the product can be improved concerning the merits of rotary stamping-forging and local heating methods combined in this near-net-shape forming process, and therefore meeting the demands of green manufacturing.In order to provide a reference for the heat input in this new process, a motion controlling model was built, as well as a power controlling model based on a Gaussian distributed flame heat source. FEM and experiments were used to analyze the forming results. In general, the local-heating rotary thickening process can be divided into two stages: preheating and thickening. In preheating, the heating zone remains unchanged in the rim part of the rotating disk. At the meantime, elastic deformation happens due to the feeding of the grooved roller. In thickening, the roller continues to feed and begins to extrude the blank rim part, during which plastic deformation dominates. Meanwhile, flame heaters start to move along with the roller and heat the deformation forefront continuously.The results of FEM show that the heating in both preheating and thickening processes makes the temperature field in the blank distributed in gradient, which will result different material strengths in sections with different forming needs. Compared with cold rotary thickening process, the stress concentration in the deforming section is improved and a more uniform stress field is found. Besides, the requiring forming force is decreased, which is good for stable thickening processes for large-sized blanks.Specific to the effects of flame heating on forming quality, the proper peak value of the preheating temperature should be no more than 500°C, and the target temperature of the deformation forefront in thickening process should be no less than 550 °C. In experiments, the corresponding temperatures were controlled around 450°C and 950°C, and the other parameters were kept the same as the simulation. As a result, the maximum rim thickening ratio in a single pass was found to be 2.72, which greatly improved the forming limit of the rotary thickening process.