Experimental and Numerical Analysis of Stainless Steel Microtube in Flaring Process

This study, with experiments and comparisons, aims to analyze the difference of stainless (SUS316L) microtubes in the flaring forming among dies with various semicone angles (35°, 40°, 45°, 50°, and 55°). The flow rule by Prandtl-Reuss combined with the finite element deformation theory and updated Lagrangian formulation (ULF) is applied to establish the finite element analysis equation for an incremental elastoplastic deformation to simulate the microtube flaring process. The broad algorithm is utilized in the forming process for the elastoplastic state and die contact. The simulation data allow acquiring the deformation traceability, the relationship between punch load and punch stroke, the distribution of stress and strain, the distribution of the thinnest thickness resulted from dies with different semicone angles, and the distribution of flaring radius caused by dies with distinct semicone angles in the forming process. The experimental result presents similar results to the relationship between punch load and punch stroke and the simulation of the coefficient of friction , revealing the analysis being suitable for the analysis of microtube cone angle flaring process. The analysis and experimental results show that the thinnest thickness of the microtube increases with increasing semicone angles of dies and the maximal flaring radius of microtubes increases with increasing semicone angles of dies.