Multiphysics numerical modelling of backward flow forming process of AISI 5140 steel

Flow forming is a cold working process that makes it possible to produce high-precision thin -walled rotational symmetric parts leading to increased mechanical properties. The backward flow forming process is numerically modelled with the finite element method (FEM) based on FORGE (R) NxT 3.2 software, which is used in this work. In order to obtain all elasticity, thermal, physical, and plasticity properties of the AISI 5140 steel material, JmatPro Software is used. The obtained material parameters are defined in FORGE (R) NxT 3.2 software. For this purpose, microstructural characterization, hardness properties, stress distribution, and strains of samples are figured out. The experimental results are compared with the FEM. The thermomechanical properties and power distributions are carried out in this work. It is well understood that the plastic deformation mechanism plays a significant role in the workpiece temperature during the flow forming process. The hardness and mechanical properties of the AISI 5140 preform increase significantly after flow forming. The grain direction in the longitudinal direction with grain refinement is also observed. The results show that Arbitrary Lagrangian Eulerian (ALE) formulation is a very efficient method for providing very high accurate hardness properties of the workpiece during the flow forming process simulation. The stress distribution, mechanical properties, process temperature, strain rate, dimensional changes, radial, and axial forces are investigated using ALE formulation. In order to validate the FEM results, the same forming process parameters are experimentally per-formed on annealed AISI 5140 steel tube with a 65% flow forming reduction ratio. Furthermore, axial and radial forces are compared between experimental and simulation. The results show that the final part hardness difference is around 1.5%, and reaction forces error is less than 10% for both radial and axial directions.

Automated summary

This paper investigates the plastic deformation mechanism, hardness and mechanical properties, stress distribution, and strain of AISI 5140 steel during flow forming process through experimental and numerical simulation. The results show significant improvement in hardness and mechanical properties of the part after flow forming.