Research On Preparation Of WE43 Magnesium Alloy Piston Semi-solid Extrusion

The use of heat-resistant rare-earth magnesium alloy semi-solid forming process can not only bring the advantages of reduced fuel consumption,low emissions and low noise to the engine,but also make the piston structure after forming small and good mechanical properties.In this paper,the WE43 magnesium alloy is selected as the experimental material and preparation of semi-solid billet by electromagnetic stirring method,and optimize process parameters.Through experimental and simulation,the following results can be got:Firstly,The effects of electromagnetic stirring parameters on the microstructure and properties of WE43 magnesium alloy semi-solid forming.Electromagnetic.Investigate the effects of different electromagnetic stirring parameters 0A,90 A,120A,150 A at 10 Hz on microstructure and mechanical properties of WE43 magnesium alloy.It is found that the grain size rang is 114?m-150?m;The tensile strength rang is 141MPa-165MPa;The elongation rang is 2.8%-5.2%,suitable process parameters are electromagnetic stirring frequency 10 Hz,current 150 A,respectively,billet grain size 114?m,tensile strength 165 MPa,elongation 5.2%.Using the thermocouple analysis method to obtain the solidification curve of the blank prepared under the condition of electromagnetic stirring parameter of 10 Hz 150A,which shows the range between solidus and liquidus of WE43 magnesium alloy is 525°C-640°C.The secondary heating temperature is 610°C and the temperature is kept for 45 minutes to obtain a semi-solid slurry of WE43 magnesium alloy.Under such conditions,?-Mg rose-type primary phase can be obtained.The finite element simulation software is used to simulate the mold temperature,billet reheating temperature,filling method extrusion casting process.the distribution of temperature field in the filling process of different forming methods of the piston is analyzed,predicted the possible location and type of piston defects.It is found that piston complete without gate extrusion at mold temperature 300?,billet reheating temperature 610?,maximum extrusion pressure.Finally,the structure observation and mechanical property test of the piston formed by semi-solid squeeze casting showed that the grain size is significantly refined after semi-solid extrusion,in which the grain size is significantly refined to 10?m,and tensile strength and elongation rise up to 215 MPa and 7.15%,respectively.