Finite Element Simulation and Experiment of Six-Axis Free Bending & Twisting Forming (6fbtf) of 304 Stainless Steel Square Tube Spiral Component

Stainless steel square tube components with complex spatial shapes are widely used in the fields of vehicles, ships, construction machinery and construction. Due to these components tend to be diversified in shape, the ordinary three-axis free bend-ing technology can not keep up with the high-quality forming requirements of com-plex square tube components. Therefore, based on the principle of six-axis free bending & twisting forming (6FBTF) technology, an analytical model of bending die trajectory of eccentric structure was established, which can continuously change the eccentricity direction of the component and realize the one-time forming of the square tube spiral component by adding additional cross-section twist angle in the bending forming process. The error between the results of the finite element model established based on the analytical model and experiment is less than 4.06%, which confirms the correctness and reliability of the analytical model and finite element simulation. On this basis, the stress–strain, wall thickness distribution and cross-section distortion law during the forming process of the 304 stainless steel square tube helical axis member are also studied. The results showed that the equivalent stress on the edge of the square tube was greater than the equivalent stress on the surface during forming, the wall thickness reduction on each cross-section only oc-curred on the outer side of the bending, and the distortion of the inner and outer sec-tions of the twist was much larger than that of the inside and outside of the bending. The results of this study have guiding significance for the 6FBTF of complex square tube components