Predictions of formability parameters in tube hydroforming process

Abstract

Abstract The objective of this study is to improve the bulging and minimize the thinning ratio to enhance manufacturing of components in Industries. Tube hydroforming is an advanced manufacturing technology used for making intricate and complex tubular parts which required less cycle time. This research focuses on hydroforming process, formability and process parameters design to replace the conventional tube bending, welding and cutting operations. The prediction of parameters is done by applying numerical and experimental approach. During experimentation the pressurized fluid is used to deform the tubes in a plastic deformation. In this study, two types of grade materials are used such as AISI304 and AISI409L of 57.15 mm external diameter with 1.5 mm thickness in the form of electric resistance welded tubes to measure stain path, thinning and bulge height. However, it is observed that the internal pressure and L/D ratio are effective parameters in both numerical analysis and experimentation. In axial feed condition, it is observed that 16.3% thinning in weld region and 44.6% thinning in base metal region, whereas, in fixed feed condition, it is observed that 7.7% thinning in weld region and 18.6%thinning in base metal region for L/D = 1 and L/D = 3 respectively. The numerical analysis with experimental results shows a very good match. It is seen that the axial feed leads to better formability with fixed feed condition because in axial feed condition material supplies towards the center of the bulge tube. The feasibility of the hydroforming process for manufacturing of AISI304 and AISI409L grade material as per the requirements of the industries is also checked. The maximum bulging is observed in L/D = 2 by comparing with the other ratios. This process can be effectively used for AISI304 grade material because the formability is better than AISI409L. Article highlights The strain path measured and predicted at necking point for ERW tube in both weld and base metal. Thinning is measured during bulging of tube under the axial and fixed feed condition. For L/D = 1 ratio observed strain distribution in unidirectional and L/D = 2, 3 observed in plane strain and bidirectional respectively.