Numerical simulation study on the cold thread rolling forming of Ti-6Al-4V alloy fasteners with external threads and their defects.

Abstract A three-dimensional numerical finite element model for cold rolling forming of external threads on Ti-6Al-4V alloy fasteners for aerospace applications was established using DEFORM-3D. This model was employed to investigate the characteristics of the cold rolling forming process and analyze the defects associated with the rolling operation. The stability of the ratio between torque and tangential load at the radius value of the rolling wheel (72.5) validates the accuracy of the model. The research results indicate that due to the unevenness of the extrusion force, the metal flow velocity is higher adjacent to the tooth-shaped surface compared to the central position. This causes the metal on both sides to accumulate and squeeze towards the middle position at the tooth top, ultimately resulting in tooth top folding defects.