THERMAL-STABILITY OF MANGANESE-STABILIZED STAINLESS-STEELS

Previous work on experimental high-manganese reduced-activation austenitic stainless steels demonstrated that they had improved tensile properties relative to type 316 stainless steel (316 SS) in both the annealed and 20% cold-worked conditions. Seven steels were tested, which included an Fe-20Mn-12Cr-0.25C (in wt%) base composition, and this composition with various combinations of Ti, W, V, P, and B. Tensile tests have now been completed on these steels after thermal aging to 5000 h at 600 degrees C. Thermal stability varied with composition, but the alloys were as stable or more stable than 316 SS. After aging to 5000 h at 600 degrees C, the strength of the annealed steels increased slightly, and the strength of the cold-worked steels decreased. In both conditions, a steel with a combination of all the alloying elements had the best strength after thermal aging. Despite having higher strength than 316 SS after aging, the ductility of the strongest alloy was still as good as that of 316 SS.