Abstract:
In order to reduce the defects of porosity,inclusion,insufficient pouring,shrinkage cavity and porosity of the shell produced in the sand casting process and improve the qualification rate of the shell cast,three kinds of casting process schemes were designed according to the process characteristics of the shell cast.The effects of pouring temperature and velocity on filling,solidification process,the volume of shrinkage and porosity of sand casting were studied by using computer simulation software.The effect of pouring temperature and velocity of the third process scheme on the volume of shrinkage and porosity was studied by orthogonal experiments.Finally,the optimized process parameters of pouring temperature and velocity were verified by experiments.The results show that both the first and second process schemes have the defects of insufficient pouring on the top of the castings,and the volume of shrinkage and porosity of the third process scheme were significantly reduced in the third process scheme.Therefore,the third scheme was better.The optimized pouring temperature and velocity were 1 560 ℃and 1.6 m/s.Under this process parameters,the volume of shrinkage cavities and porosity of the shell casting has the smallest value of 1.416 cm3.According to the calculation result,the qualification rate of the casting is 96%,and the microstructure and mechanical properties of castings meet the requirements.The third scheme can shorten the trial production cycle,reduce the production cost and improve the economic benefits.This study can provide reference for the design of sand casting technology of shell steel castings.
