The beneficial influence of high Nitrogen alloying of different Stainless Steel (FINS) grades, leading to increasing corrosion and mechanical resistances has been well established by many laboratories and R-D centers. The present paper aims to show that nitrogen alloying is also resulting in many innovations for steel technologies such as steel making, thermomechanical treatments, tool steels, bainitic and TRIP steels. Because interstitial elements such as H, C, N,... play a key role on alloys properties, revisited basic research on nitrogen alloying such as those performed by atomic scale simulations contribute to a much deeper understanding of micromechanisms controlling properties of steels and therefore should participate to increasing performances of steel.