Influence of process parameters on the forming results of large-sized cylindrical parts during counter-roller spinning

Abstract

As an advanced plastic-forming method, counter-roller spinning (CRS) is mainly applied to process large-sized, thin-walled cylinder for aerospace rocket engine. Medium carbon quenched and tempered steel 30CrMnSiA is a typical material for solid rocket motor due to its high strength, high toughness and good fatigue resistance. The determination of complex process parameters and the detection of multiple forming indexes are necessary for the study of CRS. In this paper, a finite element (FE) model for CRS of 30CrMnSiA cylinder with a diameter of 2.25 m was established and verified according to the experimental data. The effects of multiple process parameters on the forming results were studied and analyzed by orthogonal experiment. Results reveal that the thinning ratio is the most important process parameter for all the forming results. Larger thinning rate can improve production efficiency but reduce forming accuracy and require equipment to provide greater spinning force. The influence laws of process parameters on the forming accuracy and spinning force of the outside of the cylindrical parts are similar to that of the inside of the cylindrical parts. In addition, the forming accuracy error and spinning force of the inside of the cylindrical parts are smaller than that of the outside of the cylindrical parts. Thus, the forming force and positioning accuracy of the outer roller holder can be given priority when developing the CRS equipment. Based on the ANOVA results, a multivariate nonlinear regression analysis was performed on the forming results by selecting significant process parameters as independent variables. The optimal range of process parameters for obtaining good forming results was obtained by processing the regression equation.