티타늄 용탕의 산화칼슘 및 흑연과의 반응 및 기포 결함의 형성에 미치는 압력의 영향

The Reactions of the Ti Melt with CaO and Graphite and the Effect of Pressure on the Formation of Gas Porosity

Titanium was melted in the CaO-coated alumina crucible and the reaction between the melt and the coating layer was negligible. The volume fraction of the gas porosity was decreased with increasing pressure and the sound bar castings with no porosity was obtained under the Ar atmosphere of the pressure of $300kN/mm^2$. The surface of the casting obtained from CaO-coated graphite mold was slightly rougher than that from graphite without coating. The reaction product of titanium melt with the layer of CaO was mainly titanium oxide and that with graphite crucible was titanium cabide with small amount of titanium nitride.