Research On Single-Point Incremental Hot Forming Limit Of AZ31B Magnesium Alloy Sheet

As people pay more and more attention to environmental pollution,magnesium alloy materials have become a new type of material that reduces energy consumption,protects the environment,and sustains development.The types of magnesium alloy sheet forming processes have become more and more extensive.Single-point incremental forming technology is a new type of sheet metal forming process.As a forming technology without a mold or using simple molds,it makes up for the long production cycle,high manufacturing cost and manufacturing process of stamping forming technology in the process of making molds.The shortcoming of low precision of parts,can produce parts of different shapes in a short period of time,suitable for individualized production of parts and small batch flexible production.Therefore,the single-point incremental forming process of magnesium alloy sheet has been extensively studied by many scholars,and it also has broad application development prospects.In this article,the magnesium alloy material is selected as AZ31B magnesium alloy,which has good mechanical properties and is often used as a deformable material.Because AZ31B magnesium alloy has poor formability at room temperature,this article will select the physical properties of AZ31B magnesium alloy at high temperature.The finite element simulation is used to study the forming limit depth of straight-walled cylinder under single-point incremental hot forming of AZ31B magnesium alloy.Firstly,obtain the main physical parameters of the metal materials such as the density,Poisson’s ratio,and barlat constant of AZ31B magnesium alloy at 250℃ by consulting the data,and then pass the uniaxial tensile test of the AZ31B magnesium alloy sheet and calculate the corresponding values to obtain the rolling The elastic modulus,thickness anisotropy index,strain hardening index,strain hardening coefficient in the 0°,45°,and 90° directions are averaged,and the measured physical parameters are substituted into the selected Barlat three-parameter yield model.This model As a finite element model of AZ31B magnesium alloy single-point incremental hot forming.Secondly,using the Box-Behnken sampling experiment in the response surface method,the finite element numerical simulation of the first pass of the straight-walled cylindrical forming part was carried out,and the tool head diameter,downward pressure,feed speed and forming were studied.The influence of the angle on the minimum wall thickness of the formed part,a set of process parameters for the best forming performance in the AZ31B magnesium alloy single-point incremental hot forming is obtained,that is,the tool head diameter is 10 mm,the downward pressure is 1mm,and the feed speed is 1200mm/min,the forming angle is 40°.Then,through the conventional tool path from top to bottom and from outside to inside,a boss will appear on the straight-walled cylindrical part.Aiming at this problem,the tool path is optimized.The study found that the first pass and the third When the pass is formed clockwise from top to bottom,from outside to inside,the second pass is formed from bottom to top,from inside to outside counterclockwise,and the third pass is formed with a forming distance of 1mm,the final forming performance is the best.Finally,use a set of parameters that are optimal for forming performance to explore the ultimate depth of the straight-walled cylindrical part that can be formed by changing the forming angle of each pass,and find the influence of the forming angle of each pass on the forming limit depth of straight-walled cylindrical parts.