Experimental and numerical investigation of U profile production process from bimetallic strip by roll forming

This study investigates the fabrication of bimetallic strips comprised of Al 1050 aluminum alloy and 304 stainless steel through the roll bonding technique, followed by their transformation into U-profiles employing roll forming methods. This study concentrates on the experimental and numerical evaluation of manufacturing defects, particularly longitudinal bowing and edge waviness, which occur during the U-profile forming process. Initially, the surfaces of Al 1050 and 304 stainless steel plates were prepared through acetone cleaning and polishing, subsequently undergoing annealing and roll bonding processes. The resulting bimetallic strips were subsequently roll-formed into U-profiles. The central focus of the study was to methodically alter essential machine setting parameters, specifically the bending angle increment and the inter-station distance, in order to assess their impact on the aforementioned defects. The results demonstrate that the increase in bending angle is the most critical factor influencing both longitudinal bowing and edge waviness. Moreover, a suitable limit for the distance between stations was determined; distances falling below this threshold led to inconsistent increases in strain values, while variations exceeding this limit did not produce additional enhancements in the quality of the profile section. The experimental results have been verified by means of Finite Element Analysis (FEA), showing a strong correlation between the empirical and numerical data. This study provides essential insights into the optimization of roll forming parameters aimed at minimizing defects in bimetallic U-profiles.