Law of Metal Flow of Thin-Walled Conical Part With Variable Section During Spinning

Due to the influence of the loading mode of the spinning wheel and the shape of the formed part, the law of metal flow of conical thin-walled part with variable section during spinning is relatively complicated. The flange is prone to be unstable because the metal in the flange part still has a flow tendency after the unloading of the spinning part, resulting in wrinkling and other defects. In this paper, the variable cross-section conical part of superalloy GH1140 is taken as the research object, and the spinning forming process is numerically simulated by using Simufact Finite Element software. The metal flow velocity of 20 points along the axial distribution after the end of the forming process and after the unloading of the rotary is compared, and the metal flow in each stage of the forming process is analyzed. When the rotate wheel rotates anticlockwise relative to the sheet metal, the metal is affected by the tangential force anticlockwise and the radial force pointing to the center of the circle. Therefore, the whole metal flows in the clockwise direction and moves in the negative direction of the rotary wheel feed, showing a spiral downward trend. The first 40% of the forming stage is shear spinning, and the last 60% of the forming stage is conventional spinning. The flow velocity shows an annular distribution as a whole because the metal flowable area increases as the increase of the cone diameter. The metal near the center of the circle flows more slowly, while the metal away from the circular flange flows more quickly. The area with the highest flow speed is the end point of the rotary wheel feed. The velocity of metal flow decreases gradually in the direction of thickness, which is affected by the collective effect of the core mold speed and the feed ratio of the spinning wheel. Under the feeding action of the spinning wheel, the metal in front of the spinning wheel is subjected to axial tensile stress, tangential and radial compressive stress, resulting in a strain state of one-way tension and two-way compression. The metal moves along the negative direction of the rotary wheel feed, resulting in the increase of sheet wall thickness. The correctness of the model in this paper is further verified by spinning experiments. The results of the research provide a theoretical basis for analyzing the mechanism of forming defects and improving the quality of spinning forming of conical thin-walled parts with variable sections.