274 Int. J. Manufacturing Research, Vol. 11, No. 3, 2016 Copyright © 2016 Inderscience Enterprises Ltd. Modelling and simulation of single and multi-pass flow forming to investigate the influence of process parameters on part accuracy Mithun Haridas Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham (University), Amrita Nagar P.O. 641112, Coimbatore, India Gopi Gopal Defense Research and Development Laboratory (DRDL), Kanchenbagh, Hyderabad – 500058, Andhra Pradesh, India Ajith Ramesh* Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham (University), Amrita Nagar P.O. 641112, Coimbatore, India Email: r_ajith@cb.amrita.edu *Corresponding author Ramesh Kumar Katta Defense Research and Development Laboratory (DRDL), Kanchenbagh, Hyderabad – 500058, Andhra Pradesh, India Abstract: Flow forming is an incremental forming process used for making long, thin-walled seamless tubes with high strength and dimensional accuracy. This is carried out by compressing the pre-formed tube using one or more rollers, leading to the plastic flow of material in the radial, axial, and tangential directions. This ultimately results in reduction in thickness and elongation of the tube. In order to achieve the required accuracy and to reduce the shop floor costs, a better understanding of the influence of process parameters on part geometry, deformation mechanism, and stress-strain patterns will be required. This paper describes the development of a detailed finite element model, using Abaqus/Explicit, to accurately simulate the flow forming process for AISI-1045 MC-Steel, and attempts to predict the influence of process parameters like axial stagger, feed ratio, and percentage reduction, on output parameters like ovality, diametral growth, and spring back. The effect of multi-pass on surface finish is also investigated. [Received 26 August 2015; Revised 1 July 2016; Accepted 12 July 2016]