Hole flanges are commonly manufactured in mass production by conventional press-working. In an industrial context, the process limits are usually evaluated by means of the Limiting Forming Ratio (LFR), which defines the maximum attainable diameter of the flange related to the initial pre-cut hole. Nevertheless, the LFR does not provide enough information about material deformation, thickness distribution or the expected onset and type of failure. In this sense, a systematic investigation using the Forming Limit Diagram (FLD) is needed. Under these circumstances, the aim of this work is to provide a better understanding of the deformation process in conventional hole flanging, analysing the effect of the punch edge radius as well as the influence of the strain distribution along the hole flange on formability. An experimental campaign on 1.6 mm thickness AA7075 annealed sheet was completed using cylindrical punches with different profile radii. In addition, numerical modelling of the process using finite elements was developed. The results allow better understanding of the physical mechanisms governing material deformation and process formability in very ductile materials. In this regard, this research work contributes to the current state of the art in conventional hole flanging by establishing the modes of failure that prevail in the process and the influence of the bending induced by the tool radius in the flange formability. In addition, the limitations of using conventional FLD for providing a limiting threshold for the strain states attained in the flanges deformed with different punch profiles are also identified.

孔法兰通常通过常规冲压加工成批生产。在工业环境中，通常通过极限成型比（LFR）来评估工艺极限，该极限比定义了与初始预切孔相关的法兰的最大可达到直径。尽管如此，LFR没有提供足够的有关材料变形，厚度分布或预期的起因和破坏类型的信息。从这个意义上讲，需要使用成形极限图（FLD）进行系统研究。在这种情况下，这项工作的目的是更好地了解常规孔翻边中的变形过程，分析冲头边缘半径的影响以及沿孔凸缘的应变分布对可成形性的影响。使用具有不同轮廓半径的圆柱冲头完成了对1.6毫米厚AA7075退火板的实验。此外，还开发了使用有限元对过程进行数值建模的方法。结果使人们更好地了解了在韧性非常高的材料中控制材料变形和过程可成型性的物理机制。在这方面，这项研究工作通过建立过程中普遍存在的失效模式以及由刀具半径引起的弯曲对法兰可成形性的影响，为传统的孔翻边技术提供了最新的技术。此外，还确定了使用常规FLD为通过不同冲头轮廓变形的法兰中获得的应变状态提供极限阈值的局限性。这项研究工作通过建立过程中普遍存在的失效模式以及由刀具半径引起的弯曲对法兰可成形性的影响，为传统的孔翻边技术提供了最新的技术。此外，还确定了使用常规FLD为通过不同冲头轮廓变形的法兰中获得的应变状态提供极限阈值的局限性。这项研究工作通过建立过程中普遍存在的失效模式以及由刀具半径引起的弯曲对法兰可成形性的影响，为传统的孔翻边技术提供了最新的技术。此外，还确定了使用常规FLD为通过不同冲头轮廓变形的法兰中获得的应变状态提供极限阈值的局限性。