Modeling and experimental verification of tubular product formation during spray forming

A mathematical model is formulated to predict the shape evolution and the final geometry of a tubular product prepared by spray forming. The effects of several important processing parameters on the shape evolution of the tube are investigated. The model is validated against experiments of spray formed large diameter tubes. The experimental and the modeling results show that there are three distinct regions in the preform, i.e., the left transition region, the middle uniform diameter region and the right transition region. The results show that the atomization parameters as and bs, traversing speed v of the substrate, the outer diameter D0 of the substrate, and the initial deposition distance d0 play important roles in the contour and the wall thickness of the spray formed tube. But the angular velocity ω of the substrate has little effect on the buildup of the deposit. After a certain time from the beginning of the process, the deposit will come into a steady growth state. In addition, an equation is provided to estimate the wall thickness of the deposit under the steady growth state based on the mass conservation.