On the basis of developing and perfecting the conventional process, a new process method has been developed to further improve the quality of castings, increase production efficiency, and expand the application range of investment casting. Foundry, 1978, No. 6, reported that the Beijing Oil Pump and Oil Nozzle Factory adopted the cage-type combined large module process. Each component of the cage ensures sufficient rigidity of the module and doubles as a gating system, increasing the utilization rate of molten steel by about 10%. Hebei Institute of Technology, etc. control the solidification time of castings, sprues and gate rods, so that M pieces ≤ M in ≤ M rods, and the solidification ends between the sprue and the gate rod, and the liquid in the gate rod Metal pours back into the hearth for gateless investment casting. In 1982, the second issue of "Foundry" reported that Tsinghua University and others used vacuum suction casting to fill and control the solidification time. When the sprue was solidified and the sprue was not solidified, the vacuum was released, and the liquid alloy in the sprue was returned to the furnace. This process has strong filling performance, produces thin-walled castings, and has high utilization rate of molten steel. The release of the suction casting vacuum is determined according to the thermal conductivity of the shell and the solidification time of the suction casting. The third issue of "Foundry" in 1984 published an article by Ye Shengyong introducing the electrophoretic shell making process. A conductive coating is dip-coated on the wax module, and a small amount of chain phosphate is added to the electrophoresis suspension as an electrolyte, so that the surface of the refractory material adsorbs cations. Electroosmosis occurs, forming a shell with a certain strength. The electrophoresis shell-making process is few, and the production cycle is short. The fourth issue of "Foundry" in 1984 reported that Northwestern Polytechnical University used hemihydrate gypsum, plus quartz powder, quartz glass, and clay as refractory fillers in the gypsum mold casting process to produce large and complex aluminum alloy castings. 621 uses hemihydrate gypsum and coal plaster as refractory fillers to reduce the shrinkage of the gypsum shell and reduce cracking. Titanium and its alloys are important aerospace and petrochemical materials. In the late 1970s, investment casting began to produce titanium alloy castings. my country is one of the five largest investment casting titanium alloy producers in the world. The second issue of "Foundry" in 1979 published the Shanghai Iron and Steel Research Institute's production process of titanium alloy investment casting by using propane to crack under high temperature and vacuum, and to vapor-deposit graphite on the surface of the corundum (ethyl silicate hydrolyzate shell). Beihang Materials The research institute uses phenolic resin as a binder, graphite powder (sand) as a refractory material to produce graphite shells, roasts in a vacuum resistance furnace, carbonizes resin binders, and produces shells with good strength and air permeability to produce titanium alloys High-speed pressurized blade. Shenyang Foundry Research Institute published an article in "Foundry" No. 3 in 1986, introducing the use of ZTS-1 resin and toner to prepare coating, p-toluenesulfonic acid as curing agent, and graphite sand and ethanol to prepare coated sand , making mold shell, mold shell through high temperature roasting and vacuum treatment to produce titanium alloy casting process. "Casting" published an article by Li Bangsheng in the seventh issue of 1987, using zirconia ceramic powder and zirconium sol as binder to prepare coatings , to prepare the shell, and to carry out research on the production of titanium alloy investment casting.
On the basis of developing and perfecting the conventional process, a new process method has been developed to further improve the quality of castings, increase production efficiency, and expand the application range of investment casting. Foundry, 1978, No. 6, reported that the Beijing Oil Pump and Oil Nozzle Factory adopted the cage-type combined large module process. Each component of the cage ensures sufficient rigidity of the module and doubles as a gating system, increasing the utilization rate of molten steel by about 10%. Hebei Institute of Technology, etc. control the solidification time of castings, sprues and gate rods, so that M pieces ≤ M in ≤ M rods, and the solidification ends between the sprue and the gate rod, and the liquid in the gate rod Metal pours back into the hearth for gateless investment casting. In 1982, the second issue of "Foundry" reported that Tsinghua University and others used vacuum suction casting to fill and control the solidification time. When the sprue was solidified and the sprue was not solidified, the vacuum was released, and the liquid alloy in the sprue was returned to the furnace. This process has strong filling performance, produces thin-walled castings, and has high utilization rate of molten steel. The release of the suction casting vacuum is determined according to the thermal conductivity of the shell and the solidification time of the suction casting. The third issue of "Foundry" in 1984 published an article by Ye Shengyong introducing the electrophoretic shell making process. A conductive coating is dip-coated on the wax module, and a small amount of chain phosphate is added to the electrophoresis suspension as an electrolyte, so that the surface of the refractory material adsorbs cations. Electroosmosis occurs, forming a shell with a certain strength. The electrophoresis shell-making process is few, and the production cycle is short. The fourth issue of "Foundry" in 1984 reported that Northwestern Polytechnical University used hemihydrate gypsum, plus quartz powder, quartz glass, and clay as refractory fillers in the gypsum mold casting process to produce large and complex aluminum alloy castings. 621 uses hemihydrate gypsum and coal plaster as refractory fillers to reduce the shrinkage of the gypsum shell and reduce cracking. Titanium and its alloys are important aerospace and petrochemical materials. In the late 1970s, investment casting began to produce titanium alloy castings. my country is one of the five largest investment casting titanium alloy producers in the world. The second issue of "Foundry" in 1979 published the Shanghai Iron and Steel Research Institute's production process of titanium alloy investment casting by using propane to crack under high temperature and vacuum, and to vapor-deposit graphite on the surface of the corundum (ethyl silicate hydrolyzate shell). Beihang Materials The research institute uses phenolic resin as a binder, graphite powder (sand) as a refractory material to produce graphite shells, roasts in a vacuum resistance furnace, carbonizes resin binders, and produces shells with good strength and air permeability to produce titanium alloys High-speed pressurized blade. Shenyang Foundry Research Institute published an article in "Foundry" No. 3 in 1986, introducing the use of ZTS-1 resin and toner to prepare coating, p-toluenesulfonic acid as curing agent, and graphite sand and ethanol to prepare coated sand , making mold shell, mold shell through high temperature roasting and vacuum treatment to produce titanium alloy casting process. "Casting" published an article by Li Bangsheng in the seventh issue of 1987, using zirconia ceramic powder and zirconium sol as binder to prepare coatings , to prepare the shell, and to carry out research on the production of titanium alloy investment casting.