Structural integrity of multipart torispherical cylindrical head shells made by the incremental sheet forming
The paper presents the results of testing the mechanical properties and evaluating the integrity of cylindrical head shells, which were obtained by the welding process and shaped by the cold process of gradual local deformation, i.e. the process of incremental deformation. Cylindrical head shells of pressure vessels are made from one part, but the standards also allow production in a welded version when the dimensions of the floors are larger than the standard dimensions of the sheets for production. Geometric shape and measurement tolerances are defined by a series of recommendations. The required mechanical properties and acceptance criteria for installation in pressure equipment are prescribed by PED 68/2014/EC and the BAS EN 13445 recommendation. The mechanical properties of the welded joint and the deformed material in the torospheric zone of the head shells, such as toughness, hardness and crack toughness, or their values are input parameters for determining the integrity of the floor structure. Using fracture mechanics criteria, detected faults can be categorized and evaluated with regard to the acceptability of the head shells for installation in pressure equipment or continued operation. The aim of the test is to determine the influence of the type of material, thickness and diameter of the head shells on the mechanical properties (ReH, Rm, A5 and KIc) and on the integrity of the cylindrical head shells.