Research On Micro-drawing Deformation Behavior And Numerical Simulation Of SUS304 Stainless Steel

In the past ten years,with the rapid development of science and technology,microelectromechanical systems have been widely used in industrial production,so there is a great demand for the processing and manufacturing of micro-formed parts.At present,there are many methods for processing micro parts,including precision and ultra-precision machining,ion etching,laser technology,LIGA and micro-EDM technology.The relatively high manufacturing cost has been unable to meet the needs of product production.Therefore,microplastic forming technology began to develop,which is a plastic manufacturing process for producing parts in the sub-millimeter range in at least two directions.It combines the method of macro plastic processing technology,which has high processing efficiency,low production cost and can generate complex shapes in batches.Features of molded parts.However,due to the reduction of the size of the production parts,a phenomenon different from the macroscopic plastic forming will occur in the processing process.Therefore,it is one of the problems to be solved urgently to study the influence of the size effect in the microplastics on the formed parts.The main contents and conclusions of this study are as follows:(1)Firstly,50μm thick SUS 304 stainless steel foil was annealed and heat treated.The annealing temperature was 950℃,1050℃ and 1100℃ to obtain different grain sizes.The particle sizes were: 10.9 μm,20.5 μm and 35.4 μm,respectively.And the flow stress of the material shows a decreasing trend with the increase of the internal grain size of the material.(2)The micro-drawing die is designed,and the forming cup is obtained through experiments.By analyzing the stroke force-displacement curve of the drawing process,the surface quality of the forming cup and the cross-sectional analysis of the cup mouth and side wall.It is concluded that the material after annealing at 1050℃ has the best effect when forming;the thickness of the formed cup is the largest at the corner of the cup bottom,and the thickness is the smallest,and the material accumulates at the cup mouth,causing the cup mouth to thicken.(3)A micro-drawing model was established in ABAQUS finite element software,and the simulation results showed that the material was prone to stress concentration at the corners of the cup bottom.And based on voronoi mathematical theory and crystal plasticity finite element,a polycrystalline model of SUS304 stainless steel is established by neper software,and it is concluded that in the direction of plate thickness,when the grain size is the same,the smaller the characteristic size of the material,the weaker the plasticity of the material,confirming that The "smaller is weaker" size effect is in line with the HALL-PETCH formula.