When a "superequilibrium" amount of nitrogen (0.9 - 1.3%) is introduced int
o corrosion-resistant low-carbon steel with about 18% chromium, the structu
re of the steel becomes completely austenitic after cooling to room tempera
ture without alloying with austenite-forming elements (Ni, Mn, Cu, Co). The
structural transformations in cooling and heating such alloys, and hence t
heir properties, can be controlled by changing the nitrogen content.