Study on the nitrogen alloying process of nitrogen-contained 316 L stainless steel

The influences of liquid steel temperature and nitrogen partial pressure on the nitrogen solubility in 316 L stainless steel under normal atmosphere and vacuum were studied. The nitrogen solubility increased with decreasing the liquid steel temperature or increasing the nitrogen partial pressure. A thermodynamic model was developed to calculate the nitrogen solubility in 316 L stainless steel, and the calculated results were in coincidence with the measurement results under different nitrogen blowing processes. At 1 773 to 1 873 K, the nitrogen partial pressure must be over 6-28 kPa to produce 316LN (N:0.05%-0.10%, mass fraction, so as the follows), and must be over 22-101 kPa to produce 316 LN (N:0.10%-0.40%). The nitrogen content was over 0.01% in the condition of nitrogen blowing for 10 min under normal atmosphere.