Investigation of the parameters affecting the hole flanging process of the sheet metal parts

Hole flanging process is a sheet metal forming method applied to joining of the parts by any method (riveting, welding, screwing), to determine as a reference plane, and to increase the strength of the hole circumference. In this method, it is aimed to obtain a flange structure with the desired height and wall thickness without cracking and tearing on the sheet material during the forming process. In this study, the effects of hole flanging process parameters on the flange structure were investigated experimentally and analytically. DP600 and DP800 dual-phase steel sheets which are widely used in the automotive industry due to their high strength values and easy forming properties were used with 1 mm and 1.5 mm thicknesses. At the beginning of the study, uniaxial tensile tests were applied to the sheet materials in 0°, 45°, 90° according to the rolling direction and the mechanical properties of the materials were determined. Chemical properties of the sheets used were determined by X-Ray Fluorescence (XRF) analysis. In the experiments, hole flanging operations were carried out by using three different punch forms as corner curved, spherical, and conical and the effects of punch form on flanging process were investigated. In addition, cracking, tearing, flange height and wall thickness changes in the specimens were investigated depending on the material thickness, material type, punch diameter and initial hole surface quality. It has been observed that the material and process parameters directly affect the flange structure obtained in the hole flanging process. The finite element analyses were carried out by using the same parameter values with the experiments. It has been determined that the experiments performed show great similarities with the analyses. The results obtained have been brought to the literature for practical use in industrial applications of hole flanging process.