Thread rolling process of a standard bolt by finite element method

In this study, the thread rolling process of a standard ISO 4014 M30 bolt was modelled using the FEM and compared with experimental results. The aim of the study is to investigate the effects of zero adjustment and operation speed on product quality both numerically and experimentally, and to provide recommendations for the optimisation of process parameters. Modeling studies were carried out using Simufact Forming software. Simulations were performed for M30x200 bolts made of 42CrMo4 material, employing the Coulomb friction model and various die feed rates. In the experimental phase, bolts of the same dimensions and material were processed on an industrial flat die thread rolling machine. The results showed that zero adjustment plays a critical role in forming the thread profile in accordance with standards, while adjustment errors cause burr formation, contour distortion, and out-of tolerance dimensions. It was determined that deformation behavior becomes more aggressive and surface quality decreases at operating speeds above 1800 mm/s. A high correlation was achieved between the numerical modelling and the experimental findings, demonstrating the effectiveness of the FEM-based approach in process design.