Abstract: The precise control of nitrogen content of high nitrogen stainless steel is the key control factor of production. Taking Mn18Cr18N high nitrogen steel as an example， this paper studies the relationship between steel composition， temperature， nitrogen pressure and nitrogen content control in pressure induction melting process by using metallurgical principle， factage thermodynamic software and thermal state experiment and detection analysis methods.The results show that the reliability of the "composition temperature pressure" relationship equation based on the theoretical data is high， and the theoretical and predicted values of nitrogen pressure in the three heats experiment are in good agreement with the actual control values. The thermal experiment finds that when the contents of Mn and Cr remain unchanged， increasing the nitrogen partial pressure can increase the N content in the ingot， but when the nitrogen reaches about 1%， the effect of increasing the nitrogen content by increasing the nitrogen partial pressure decreases.When the content of Mn or Cr is low， the nitrogen content can be increased by increasing the nitrogen partial pressure. Reducing the content of C and Si in steel is beneficial to the alloying and stable control of high nitrogen content in steel. It is advisable to control the melting temperature of the pressure furnace at 1 500-1 550 ℃ and the nitrogen pressure at 0.225-0.325 MPa when the nitrogen content in Mn18Cr19N steel is necessary to be controlled ≥ 0.8%.

Key words: Mn18Cr18N, High Nitrogen Steel, Pressure Melting, Thermodynamics, Nitrogen Content

摘要： 高氮不锈钢中氮含量的精准控制是生产关键控制要素。以Mn18Cr18N高氮钢为研究对象，利用冶金学原理、Factsage热力学软件及热态实验与检测分析等方法，对加压感应熔炼过程钢种成分、温度及氮气压力与氮含量控制的关系进行研究。结果表明，基于理论数据的“成分-温度-压力”关系方程可信度高，3炉实验的氮气压力理论值、预测值与实际控制值吻合度良好。热态实验验证发现，Mn和Cr含量不变时，依靠提高氮分压可以提高钢锭中N含量，但是w［N］达到约1%时，通过提高氮分压增加氮含量的效果降低。Mn或Cr含量低时，可以通过提高氮分压达到提高氮含量的目的。降低钢中C和Si含量有利于钢中高氮含量的合金化及稳定控制。当需要控制Mn18Cr19N钢中的w［N］≥0.8%时，宜控制加压炉熔炼温度在1 500～1 550 ℃，氮气压力在0.225～0.325 MPa。

关键词: Mn18Cr18N, 高氮钢, 加压熔炼, 热力学, 氮含量