Study On Casting Technongy Of ZL205A Aluminum Alloy Plate

China’s Long March 5 carrier rocket has a main core diameter of 5 meters and a single wall panel of some storage tanks 5000 ×3000×10(mm).The processing equipment used in the process requires a flat plate of 5200×3200×280(mm),which must have good mechanical properties,high tissue compactness,and small internal stress is not easy to deform.According to the service conditions and mechanical properties,as-cast ZL205 A is used for this condition.By calculation,the weight of the flat plate casting reaches 10 t,which i s a thin-walled structure with a large difference in wall thickness and a large number of thermal joints.It is difficult to achieve sequential solidification,and it is easy to produce shrinkage and shrinkage defects.A three-dimensional modeling software was used to build the model,and gravity resin casting was used to select the resin sand shape,with a height of 200 mm,a tilt of 3.5 degrees,and 32 pouring risers.The casting process was simulated and analyzed by Pro CAST.The casting temperature was set at 730°C.It was affected by the prefabricated steel pipe,there are some separate areas.Through optimization analysis to increase the number of runners,using 5 straight runners,the pouring time was shortened to40 s,and cold iron was used for chillin g.Which have achieved good results in eliminating shrinkage and shrinkage.Without increasing the size of the riser,properly canceling the setting of the riser neck has certain effects on improving the riser’s shrinkage effect and controlling the shrinka ge shrinkage and loosening defects.The casting mold is made of phenolic resin with 2% resin of and 1.5%curing.The mold is dried with natural gas and the degassing time is 20 minutes.The actual casting temperature is 740 ° C.The outer riser adopts a th ermal riser,and the verification part is poured.By taking microstructure observation and X-ray fluoroscopy,no shrinkage and shrinkage defects.It is concluded that the proper increase of the pouring temperature and the use of the thermal insulation riser can effectively reduce the occurrence of shrinkage and shrinkage holes.The different positions microstructure of the large-size plate were investigated to verify simulation results of ZL205 A alloy.It can be seen that the as-cast structure of the ZL205 A alloy flat plate at nudifferent positions is the matrix α(Al)phase,the equiaxed crystal structure.The microstructures of the center and edge sections are different,but the differences are not significant.The comparison of mechanical properties experiments found that the mechanical properties of aluminum alloy flat castingsheat treatment tensile strength,elongation of 178.2 MPa and 4.56% of the as-cast state.After the T6 treatment,tensile strength,elongation of 500 MPa and 8.94%.Vibration experiments were performed using a spectrum synchronous transmission type vibration aging system.Two vibrations were implemented,the vibration aging parameters were set to 7150 rpm and 7150 rpm.The blind hole method was used to verify the actual effect of vibrat ion aging.Six stress test points were arranged on the symmetrical points of the verification piece.The average of measured elimination rates is 43%,and the elimination effect was obvious.