Research On Rotary Piercing Process Of AZ31 Magnesium Alloy Seamless Tube

Magnesium alloy material is known as the "21st century green engineering material",which has many excellent performance and has been applied in chemical industry,electronic industry,transportation,aerospace and other industries.the development of magnesium alloy applications has become inevitable trend.Rotary piercing technology as the first step of seam pipe production,which has significant influence on the quality of the capillary.Magnesium alloy has poor plastic deformation and large resistance to deformation at room temperature.In this paper,an exploratory research on seamless AZ31 tube perforation is carried out by warm rolling method.Firstly,in order to determine the temperature rolling deformation properties of the material,first,the isothermal compression test was carried out on the Gleeble-1500 D thermal simulator.The influence of different deformation conditions on the high temperature deformation behavior and the rheological stress of the AZ31 magnesium alloy was analyzed.The constitutive model and dynamic recrystallization model of AZ31 magnesium alloy were established,which provided theoretical basis for finite element simulation and metal deformation during perforation.Secondly,the BP neural network is used to predict the rolling force of AZ31 magnesium alloy in the diagonal rolling deformation zone,and the error is analyzed and compared.The maximum error is 5%,the average error is 2.4%,the minimum error is 1.4%,and the precision of the BP network is quite higher,which can meet the demand of production and provide theoretical support for the improvement of the process.Thirdly,combined with the characteristics of plastic deformation of magnesium alloy,the finite element simulation of AZ31 magnesium alloy slant rolling piercing is carried out.The effect of stress,strain,rolling force,rolling torque,damage and other deformation parameters on the wall thickness of the tube during the perforation process is analyzed.Finally,the cross rolling perforation experiment is carried out for the purpose of comparing the experimental results with the simulation results,and verify the feasibility of AZ31 magnesium alloy cross rolling piercing.It is finally determined that the rolling temperature is 400 degrees centigrade,the head extension is 20 mm,the selected feed angle 7~9 degrees,the diameter of the head diameter of 30,the diameter of the hole and throat and the roller speed 170 rpm can smooth through the magnesium alloy tube.