용강 내 복합 탈산 및 질화물 형성에 관한 연구

Abstract

본 연구에서는, 용강 내 Al, Si 및 N에 대한 열역학 관계를 질화물 평형법을 이용하여 1823~1923K 온도범위에서 조사하였다. Wagner’s formalism을 이용하여 용강 내 질소 용해도에 대한 Al과 Si의 영향과 용강 내 AlN 형성에 대한 평형상수값을 측정하였다. Fe-Al과 Fe-Al-Si-N 용강 내에서 질소 용해도와 AlN 생성을 측정하기 위해 다양한 질소 분압 하에서 고주파 유도로를 이용하여 샘플링 방법을 사용하였다. Wagner’s formalism을 이용하여 질소 용해도에 미치는 Al과 Si의 1차, 2차 영향을 측정하였다. 또한, 용강 내 AlN 형성 평형상수를 1823~1923K의 온도 범위에서 측정하였다. 용강 내 AlN의 용해도적에 미치는 Si의 영향은 Al과 Si간 열역학적 관계를 결정하기 위해 측정하였다. Fe-Al-N, Fe-Si-N 계에서 얻어진 열역학 데이터를 이용하여 Al에 미치는 Si의 활동도 계수를 1.5%Si 농도의 Fe-Al-Si-N 합금조성에서 측정하였으며 측정한 Al과 Si간의 열역학 관계를 Al-Si 복합 탈산 평형실험을 통해 실증하였다.|In the present study, thermodynamic relations among silicon, aluminum and nitrogen in liquid iron were studied using the metal-nitride-gas equilibration technique in the temperature range from 1823 to 1923K. The nitrogen solubility and aluminum nitride formation in liquid Fe-Al and Fe-Si-Al alloys were measured by the sampling method using a high frequency induction furnace under various nitrogen partial pressures. Using Wagner’s formalism, the first- and second-order effects of aluminum and silicon contents on nitrogen solubility were determined. The effect of silicon on solubility product of AlN in liquid iron was measured in order to determine the thermodynamic relation between aluminum and silicon. Using thermodynamics data obtained from Fe-Al-N and Fe-Si-N system, the first-order effect of silicon on activity coefficient of aluminum was determined in liquid Fe-Si-Al-N alloys containing up to 1.5 mass% Si. The reliability of data obtained in the present study was checked by carrying out Al-Si complex deoxidation equilibrium experiment for liquid iron.; In the present study, thermodynamic relations among silicon, aluminum and nitrogen in liquid iron were studied using the metal-nitride-gas equilibration technique in the temperature range from 1823 to 1923K. The nitrogen solubility and aluminum nitride formation in liquid Fe-Al and Fe-Si-Al alloys were measured by the sampling method using a high frequency induction furnace under various nitrogen partial pressures. Using Wagner’s formalism, the first- and second-order effects of aluminum and silicon contents on nitrogen solubility were determined. The effect of silicon on solubility product of AlN in liquid iron was measured in order to determine the thermodynamic relation between aluminum and silicon. Using thermodynamics data obtained from Fe-Al-N and Fe-Si-N system, the first-order effect of silicon on activity coefficient of aluminum was determined in liquid Fe-Si-Al-N alloys containing up to 1.5 mass% Si. The reliability of data obtained in the present study was checked by carrying out Al-Si complex deoxidation equilibrium experiment for liquid iron.