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Boron nitride based composite shell for titanium alloy investment casting precision casting
In the titanium alloy investment casting process, graphite shell was applied relatively early, and the refractory material used was graphite. The binder was also carbonaceous, usually resin or colloidal graphite.
Tungsten coated ceramic shell is a shell system developed by Rem Corporation in the United States. The characteristic of this process is to use metal organic compounds, zirconium and hafnium halides or colloidal metal oxides as binders, and tungsten powder as the surface layer refractory material.
Oxide ceramic shell is an advanced technology widely used both domestically and internationally. The surface refractory material is refractory metal oxides such as ThO2, ZrO2, or Y2O3, and the binder is refractory metal oxide colloids or metal organic compounds. Adhesive is the key to manufacturing this type of shell. This type of shell has high room temperature strength and high temperature strength, with a small shrinkage rate, which can ensure that the titanium castings poured have high dimensional accuracy and low surface roughness. Can cast large titanium castings, complex titanium castings, and thin-walled titanium castings. Oxide ceramic shells are a promising type of shell, with a tendency to replace graphite shells and tungsten coated ceramic shells.
Titanium is an extremely active chemical element [13] that has strong affinity with N, C, and O. A small amount of these atoms can reduce the ductility of titanium alloys. Current research indicates that liquid titanium undergoes varying degrees of chemical reactions with almost all molding materials, which can increase the brittleness of titanium castings, increase the thickness of the oxygen rich layer and the alpha brittle layer. However, these defects seriously affect the mechanical properties of titanium castings and bring great difficulties to the casting of titanium alloys. Seeking new molding materials with weak reaction with liquid titanium is a direction that titanium alloy casting workers have been striving for. This molding material can be used for both shell manufacturing and crucible manufacturing for melting titanium alloys
In the titanium alloy investment casting process, graphite shell was applied relatively early, and the refractory material used was graphite. The binder was also carbonaceous, usually resin or colloidal graphite.
Tungsten coated ceramic shell is a shell system developed by Rem Corporation in the United States. The characteristic of this process is to use metal organic compounds, zirconium and hafnium halides or colloidal metal oxides as binders, and tungsten powder as the surface layer refractory material.
Oxide ceramic shell is an advanced technology widely used both domestically and internationally. The surface refractory material is refractory metal oxides such as ThO2, ZrO2, or Y2O3, and the binder is refractory metal oxide colloids or metal organic compounds. Adhesive is the key to manufacturing this type of shell. This type of shell has high room temperature strength and high temperature strength, with a small shrinkage rate, which can ensure that the titanium castings poured have high dimensional accuracy and low surface roughness. Can cast large titanium castings, complex titanium castings, and thin-walled titanium castings. Oxide ceramic shells are a promising type of shell, with a tendency to replace graphite shells and tungsten coated ceramic shells.
Titanium is an extremely active chemical element [13] that has strong affinity with N, C, and O. A small amount of these atoms can reduce the ductility of titanium alloys. Current research indicates that liquid titanium undergoes varying degrees of chemical reactions with almost all molding materials, which can increase the brittleness of titanium castings, increase the thickness of the oxygen rich layer and the alpha brittle layer. However, these defects seriously affect the mechanical properties of titanium castings and bring great difficulties to the casting of titanium alloys. Seeking new molding materials with weak reaction with liquid titanium is a direction that titanium alloy casting workers have been striving for. This molding material can be used for both shell manufacturing and crucible manufacturing for melting titanium alloys
