Abstract: A method of producing castellated beam. A first continuous cut 18 is made along the web of a universal beam, and a second cut 20 is then made along the web on a path differing from the path of the first cut. The cuts are such as to define rectilinear sections (24, 26) lying on alternate sides of the centerline of the web and at least partly curvilinear sections (25, 27) joining the closest ends of adjacent rectilinear sections. The cut halves of the beam are separated and are then welded together (at 28) in regions formed by juxtaposition of rectilinear sections of the two halves. Beams, having circular, elliptical or other curvilinear openings can thus be made.