Investigation On Alumina-spinel Castable For Nickel-based Superalloy Smelting

With the rapid development of science,technology,and industrial construction,the requirements for quality and production of superalloy are becoming higher and higher.Refractory crucibles are indispensable in the smelting process of superalloy.The degree of interfacial reaction between refractory materials and alloys determines the purity of superalloy,and the service life of refractory materials also indirectly affects the superalloy’s yield.Therefore,the seat drop method was used to research the high-temperature wettability and interface characteristics between Nickel-based superalloy and different refractory materials in this study.Among the six types of refractory materials,fused white alumina,sintered Mg Al₂O₄ spinel,magnesium oxide stabilized zirconia,yttrium oxide stabilized zirconia,magnesia,and chromium oxide,the fused white alumina and sintered Mg Al₂O₄ spinel were selected as the main raw materials for the crucible for Nickel-based superalloy smelting.A series of research work had been conducted on the conventional physical properties,high-temperature performance,and corrosion and permeability resistance of alumina-spinel castables.The following conclusions were reached:（1）Fused white alumina had the best wetting resistance and corrosion resistance to Nickel-based superalloy,but it was deeply penetrated;Sintered Mg Al₂O₄ spinel had good wetting resistance with Nickel-based superalloy,it was slightly corroded,and had shallow penetration;The wetting angles between magnesium oxide stabilized zirconia,yttrium oxide stabilized zirconia,magnesia,chromium oxide with superalloy were small and the superalloy may be contaminated by them.Therefore,fused white alumina and sintered Mg Al₂O₄ spinel were selected as the main raw materials for preparing refractory crucibles for Nickel-based superalloy smelting.（2）The distribution of different elements penetrating into the refractory of Nickel-based superalloy was different.Among them,the distribution of Cr element is shallow,the distribution of Ti element was in the middle,and the distribution of Nb element was wide and deep.（3）Through a comprehensive evaluation of conventional physical properties,high-temperature performance,and corrosion resistance permeability,Secar 71 cement was selected as the binder for alumina spinel castables,with fused white alumina and sintered Mg Al₂O₄ spinel at a ratio of 8:2 as the optimal raw material ratio and 1400℃×5h was the preheating treatment process.（4）After adding Zr O₂（Y₂O₃）,Y₂O₃,Cr₂O₃,or CA₆ to the optimal formula,the corrosion and penetration resistance of the crucible sample to Nickel-based superalloy wasn’t improved significantly.Further experiments are needed to find additive that can improve the corrosion and penetration resistance of the crucible.