Research On The Hydroforming Technology Of Small Diameter Bellows

One of the extensive application of the tube hydroforming is bellow hydroforming technology, which is also the difficulty of hydroforming technology. Due to the excessively-large strain of the very complicated forming process,its analysis in theory is very difficult and the research for bellow hadroforming is not popular in domestic.In this study, according to the technical parameter of the automatic bellow forming machine developed by ourselves,the bellow hydroforming technology and forming process was researched with using the finite element simulation software and the hydraulics theoretics.In this thesis,the hydroforming process of the bellow hydroforming technology was studied principally.Based on the explanation of the bellow hydroforming process,four influencing factors were analyzed,and the computational method and computational solution of the technological parameters of bellow hydroforming were given, which provided the initial data for the simulation of the bellow hydroforming process used the finite element analysis software.The ABAQUS,finite element simulation software, was used to simulated the forming process,and the results were anlayzed.To contrast the simulation results with the different loading paths used in the simulation, the conclusion was obtained that the thinning trend of the tube well was delayed with the increase of the extrusion punch moving speed, based on the constant forming pressure, whereas the height of wave ridge reduced.Both the internal pressure and the extrusion punch moving speed were indispensable to the bellow hydroforming,and their matching relation influenced the forming process evidently.The optimal loading path for the internal pressure and the extrusion punch moving speed was the key for perfect bellow hydroforming process and the best quality of the bellow product.In this study, the304stainless steel tube with0.3mm well thickness was used in the simulation for bellow hydroforming process,with using3.0MPa forming pressure,18.5mm/s feed speed and1.5mm fillet radius of the transition region.Finally, the automatic bellow hydroforming machine was developed according to the technological parameters above-mentioned.And the solve projects of the hermetic closure for the internal pressure and forming technique were present.The equipment worked steadily, the bellow product quality was well and the technical order of the bellow hydroforming was achieved.