摘要:
An exemplary metal structure (10, 30) includes a base portion (14, 34), a flange (122, 322), and an edge portion (1241, 3241). The base portion defines a circular flanged hole (12, 32). The flange extends from a top surface of the base portion and the flange surrounds the circular flanged hole. The edge portion is configured for connecting an inside surface of the flange and the top surface of the base portion. The edge portion includes an edge surface, and a ratio of a radius of the edge surface (1242, 3242) of the edge portion with respect to a thickness of the base portion is less than 0.4. A method for making a circular flanged hole in a metal sheet (15) is also provided.