Jung-Mock Jang

Nitrogen solubility in high manganese-aluminum alloyed liquid steels

The nitrogen solubility in liquid Fe-Mn and Fe-Mn-Al alloys has been measured by the gas-liquid metal equilibration technique utilizing a high frequency induction furnace under the nitrogen partial pressures of 0.1 to 0.8 atm in the temperature range of 1773 to 1873 K. The variation of the nitrogen solubility with the addition of manganese was measured by sampling and in-situ analysis of nitrogen content. Manganese significantly increased nitrogen solubility in liquid Fe-Mn and Fe-Mn-Al alloys. The nitrogen dissolution followed the Sieverts’ law for liquid Fe-Mn alloys contained manganese up to 26 mass%. Using the Wagner’s interaction parameter formalism, the experimental results were thermodynamically analyzed to determine the first- and second-order interaction parameters of manganese and aluminum on nitrogen in high Mn-Al alloyed liquid steels. No temperature dependence of these values was observed in the temperature range of 1773 to 1873 K. eNMn = −0.023, rNMN = 0 rNMn,Al = 0 (Mn≤26 mass%, Al≤0.4 mass%, 1773–1873 K).

Nitrogen Solubility in Liquid Mn-Fe-Si-C Alloys

The nitrogen solubility in liquid Mn-Si, Mn-Si-Fe, Mn-Si-C and Mn-Si-Fe-C alloys has been measured by the gas-liquid metal equilibration technique in the temperature range of 1673–1773 K. The additions of silicon, iron and carbon significantly decreased the nitrogen solubility in liquid manganese alloys. The experimental results were thermodynamically analyzed by the Wagner’s formalism to determine the first- and second-order interaction parameters of silicon, iron and carbon on nitrogen in liquid manganese. The thermodynamic parameters can be used to predict the nitrogen solubility in ferromanganese and silicomanganese alloy melts as functions of the melt composition and temperature at given nitrogen partial pressures.