A review of flow forming processes and mechanisms

After years of purely academic interest and niche applications, today the flow forming process is increasing demand in aerospace, automotive and defense industries. This review surveys academic paper of last fifty years, in order to evaluate the current state-of-the-art for academic and practitioner. Theoretical and experimental approaches are collected and compared by evaluating their prediction models. As a result, several knowledge gaps are identified, for example stress and strain tensors evolutions are not determined for workpiece, due to high computational cost and uncertainty about the correct finite elements approach to adopt. Similarly although, the final microstructure is often evaluated for specific cases, study of its evolution during plastic deformation has not been reported. Residual stress and final material proprieties, such as corrosion behavior, have been not studied numerically or experimentally. Tool path impact and alternative geometries are not deeply explored. Particular attention is given to process experimental optimization and characterization through Design of Experiment, which is still limited to a few papers and sometimes not well developed. The results of this review will help define a research agenda for future developments.