Design of forming rolls for a high strength steel automotive body part with locally variable cross-section

摘要

study on the applicability of a variable section roll forming process to the economical manufacture of an automotive body part of HSS sheet has been carried out. In this study, a part with locally variable cross-section has been selected as an example. The corresponding forming rolls have been designed considering the sheet thickness and part shape using the CATIA software. The crosssection shape of the part to be formed at each station were obtained, translated and rotated. The transformed shapes were then interpolated to generate the surfaces of forming rolls. In the original shapes of forming rolls, lots of interference between the rolls and the sheet have been found. After carefully investigating the interferences at each station using CATIA's assembly function, the rolls have been modified to remove the interferences until the clearance between the upper and lower rolls becomes larger than the sheet thickness. To verify that the desired geometry of the part can be manufactured without any defects, elasto-plastic FE analysis was performed using a general purpose FEM software MARC. The results of the analysis are satisfactory and it is found that the roll forming process of variable section is applicable to the manufacturing of the selected part.