| High nitrogen steels have the nature of high strength, good tenacity, uniform corrosion resistance and local corrosion resistance (corrosive pitting, corrosion seam); there is no doube about its excellent nature. It is difficult to add nitrogen into the steel in smelting process. According to Sieverts law, high pressure can increase the nitrogen content, and using subaeration of nitrogen makes it feasible to gain high nitrogen steels by high pressure in theory with short time. Nitrogen is the only gaseous alloy element and it is also the most low-cost alloy element. Substituding nickel with nitrogen is a new important technology in the research of producing nitrogen steels.This paper researches the solution process of nitrogen into steel and analyses the influencing factor of thermodynamics to solution process. It is confirmed that it is feasible to add nitrogen into steel. It modifies the primary experimental equipments of the high temperature and high pressure reaction kettle and crucible for smelting and produces high nitrogen austenite stainless steels with nickel-free and more than 0.9% nitrogen content. By controlling the high pressure and bottom-blown nitrogen, orthognal experiments are done and analyzed the thermodynamic factors of different pressures, temperatures and the content of different alloy for the nitrogen content at the smelting. To prevent the nitrogen bubble's fleeing when high nitrogen steels is solidification, it should keep a high pressure all the time when solidified. Expereimental and thermodynamic analysis results have good consistency.The results indicates that among the influencing factors which influence the nitrogen solubility, pressure is the uppermost influencing factor; The content of alloy(Cr,Mn) takes the second place, and the influence of Cr is stronger than Mn; Temperature takes the third place. It also indicates that the nitrogen content increases as the pressure rises when the pressure is 0.5MPa |
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