Abstract: Nitrogen loss was primal problem during solidification process of HNS (High Nitrogen Steel). Based on thermodynamic analysis and near equilibrium experiment, the effects of wire steel composition and cooling rate on nitrogen content in melt pool were researched. Under the present conditions, it came to the following conclusions. When the nitrogen mass fraction in wire steel increase from 0.15 % to 0.90 %, the nitrogen content in pool was increased by more than two times. It will be useful to increase ratio of nitrogen in shielding gas. More and more nitrogen were kept in pool as solid-solution state rather than nitrogen bubble with increasing of cooling rate. The nitrogen content increased by more than 30 % under forced cooling design developed in the present study. The results of this paper will provide theoretical guide for controlling the escape of nitrogen element in HNS.

Key words: high nitrogen steel；solidification behavior, nitrogen loss；forced cooling