Yang Jinsong and Yu Lihua of Huazhong University of Science and Technology have studied the process of sand core of complex hydraulic valve body.They proposed that adding phenolic resin to the coated sand and using selective laser sintering system, high strength and complex hydraulic valve body coated sand cores can be sintered in a short time, and smooth inner flow path and qualified size valve body cast iron parts can be produced without coating; reasonable control of manufacturing parameters of laser sintering can result in high strength sand cores.The buoyancy of molten iron can be withstanded without placing core bones. This method successfully solves the problem that coated cores made by sintering can not place core bones.
Li Bin,Wen Houlin et al. of Guizhou University simulated flow field, temperature field and solid fraction during filling and solidification of two casting schemes of integral multi-way valve by casting simulation software ProCAST and Anycasting. In order to ensure that the sand core would not be deflected by impact of metal liquid, integral frame type was used for positioning the sand core and production experiments were carried out to verify the results.Adding the blank-holder riser can avoid the defects such as shrinkage and shrinkage holes in the multi-way valve body during the casting process, and the inner flow path of the casting is smooth; the integral frame type can ensure the positioning accuracy, improve the strength of the sand core and the accurate position of the casting flow path.
Wang Zhiping, from Lanzhou University of Technology, simulated the filling and solidification process of EPC with computer and carried out orthogonal test to analyze and compare the influence of casting mode, type of casting system and section shape of inner gate on the quality of castings, so as to determine the optimal design scheme of casting system.Wang Zhiping and Xiao Zhenrong used MAGMAsoft casting numerical simulation software to simulate flow field, temperature field and stress field during filling and solidification of valve body castings.Based on the simulation results, the casting defects that may occur during the casting process are accurately predicted, the causes of the defects are analyzed, the casting quality is evaluated and the optimized improvement scheme is put forward to eliminate and control the defects so that the casting can meet the quality requirements.