Research On Numerical Simulation Technology Of Solidification Process Of Melt Casting Charge

The casting charge is a process method of melting the explosive into a projectile or mold and cooling and solidifying into a pharmaceutical column,which is a complex thermophysical process from liquid solidification to solid.However,because the explosives are easy to form embellishment defects such as shrinkage,shrinkage holes,surfaces,cracks,etc.during the solidification process,and the detection of the quality of the charge is generally through trial production and destructive tests,which not only cannot guarantee the quality of the charge of the drug column,but also leads to long trial production cycle,high cost,low efficiency and other issues.After orthogonal optimization,the best process parameters are: pouring temperature 85 °C,explosive viscosity 5 c P,ambient temperature 30 °C,mold temperature 50 °C,through reasonable matching of process parameters,although the size of shrinkage,shrinkage holes and stress extremes can be reduced,but can not completely eliminate the charging defects.In order to further improve the quality of the drug column and reduce charge defects,the pressurized coagulation process and the hot core rod process were simulated.Through the change of the temperature of the explosives in the mold,it can be seen that applying a certain pressure to the explosives helps to improve the melting point of the explosives,shorten the solidification time,and thus improve the quality of the charge;Compared with the conventional charge casting process,under the condition of the hot core rod process,the explosives at the neck of the mouth and the shrinkage channel below it have been in liquid phase,so that the explosives in the mouth funnel can fully replenish the explosive center,which can greatly reduce the occurrence of shrinkage and shrinkage defects in the drug column.On the basis of the above charging process,a new solidification process combining pressurization + hot mandrel is further designed,and the three key process parameters of hot mandrel insertion cavity depth,hot mandrel heat temperature and applied pressure are simulated.The results show that the applied pressure has the most obvious effect on the shrinkage and shrinkage holes,and the greater the applied pressure,the fewer defects;The rise in the temperature of the hot core rod will slightly increase the shrinkage and shrinkage defects,so it cannot be ignored;Shrinkage and shrinkage defects are almost unaffected by the depth of the hot mandrel inserted into the bullet chamber,but the premise is that the insertion depth of the hot mandrel must run through the repair channel of the drug column to ensure that the shrinkage channel is completely unblocked during the operation of the hot mandrel.The research results of this paper can provide a reference for the design of the melt casting charge process.