Study On Investment Casting Technology For Large Magnesium Alloy Castings

Magnesium alloy is known as the "21st Century Green engineering material." Its density is small,and it is the lightest metal structural material.Magnesium alloy has become an important structural material in many important fields,such as aerospace,automotive,electronic communication,and other industrial fields.In developed countries such as Europe and the United States,the relevant research and industrialization departments that bind up in large-scale magnesium alloy casting precision casting technology systems are moving towards standardization.Through strict manufacture Process design,the use of precision-manufactured mold tooling,the selection of high-quality molds and casting materials,the use of high-quality alloy-specific Process equipment to obtain larger size,thinner wall thickness,large,complex,thin-walled magnesium alloy castings with higher precision and longer life for use in all types of spacecraft.And china to implement a strict technical blockade.This paper takes the precision molding system of magnesium alloy construction for spacecraft with some characteristics such as large,complex,and thin-wall structural as the research object,and designs for large thin-walled magnesium alloy melt in the Gating system for the casting of fluff,holes,and other defects of the effective control.The selection of the appropriate for large magnesium alloy melt the wax mold casting materials and casting materials,optimization of the large ceramictype housing production process;analysis of anti-gravity casting the influences the casting size error mechanism,a large magnesium alloy casting melt cast-precision control for new ideas and new ways to improve large magnesium alloy construction for the finished product rate provides strong security.In this paper,Procast software is used to construct a simulation model for casting magnesium alloy under the condition of Anti-Gravity filling.Using three coordinate measuring instruments to measure the key dimensions of the pressed wax mold under different process parameters,combined with the experimental data and simulation method,the corresponding model of the size difference and deformation of the wax molds was established the optimal waxing process parameters were obtained.A rotary viscometer measured the rheological properties of the slurry,and the formula was optimized.The basic properties such as mechanical properties and air permeability of the shell were characterized,and the shell's material system was optimized.An experimental method was used to verify the flame retardant effect of surface layer material on magnesium alloy casting.The surface roughness of the shell layer and the casting surface roughness is obtained by the surface roughness measuring instrument.By optimizing the shell material and using wire binding,the shell's performance against cracking and surface peeling is improved.Through the mechanical properties,phase,and other basic physical and chemical properties of the shell,and the measurement of the shell's size before and after roasting,the computer simulation method was adopted.The parameters' influence model on the size deviation and deformation of the shell cavity was established,and the optimal parameters of the shell were determined.Based on castings' structural characteristics and the basic properties of the shell materials,Procast software is used to simulate the size of castings under different solidification and cooling conditions.