Research On The Casting Process Of Automobile Wheel Bracket Based On MAGMA

Automobile hub bracket is an important part of automobile suspension system.It is mainly used to connect suspension frame,brake and shock absorber.It bears alternating impact load during driving,and therefore,the comprehensive mechanical properties of this part are required to be excellent.In this study,the casting process of the high strength and toughness hub bracket is studied.The professional casting simulation software MAGMA was used to simulate the filling and solidification process of castings,and the locations and causes of defects that may appear in the casting production process were predicted.In order to eliminate the defects in the castings,the casting process was optimized,and finally high-quality castings were obtained.With reference to the chemical composition of the existing national standard grade ductile iron QT450-10,using alloying methods by adjusting the content of Cu and Mn,the organization structure was optimized and the content of pearlite in the matrix increased,and the pearlite lamella was refined,a high-strength and toughness ductile cast iron with a tensile strength of 736.67 MPa and an elongation of 10.6%was obtained.According to the structural characteristics of the automobile wheel bracket castings,the casting process was designed,and the original scheme was numerically simulated with MAGMA software.The filling process and solidification process of the casting were studied by analyzing the simulation results of temperature,velocity,pressure,etc.The defect characteristics of shrinkage porosity inside the casting under this scheme were determined.The original process plan was improved from the perspective of changing the parameters of the feeder and the feeder neck and changing the pouring temperature.From the simulation results,it was found that when the pouring temperature was increased to 1425?,the height and diameter of the riser increased,and the length of the riser neck was shortened at the same time,the solidification time of the riser neck was prolonged,and the feeding capacity of the riser was enhanced,and the defects such as shrinkage porosity were reduced.However,due to the thickness of the casting over the area quite different,thick-walled parts have slow solidification speed and difficulty in feeding,so there was still a small amount of shrinkage.Therefore,cold iron was added to the thick-walled part to speed up the solidification rate of the part,promote the simultaneous solidification of parts with different wall thickness,also improve the hotspot of the section,so that the porosity completely transferred to the riser and gating,which completely eliminated the shrinkage porosity defects in the castings.