Microstructure Evolution during Recrystallization of Newly Developed Low Ni High Mn-N Stainless Steels

Abstract

Low cost stainless steels where nickel is replaced in a conventional Fe-Cr-Ni stainless steel by manganese and nitrogen were studied. In this work, three new steels based on the system (mass %) Fe-18Cr-15Mn-2Ni-2Mo-XN were prepared and their microstructure after each treatment was evaluated by optical and scanning electron microscopy, and X-ray diffraction. A good correlation between texture and microstructure evolution during annealing was established. A randomization of the texture during recrystallization of the austenite was observed. Recrystallization starts at temperatures above 850°C, and after annealing for 0.5 h at 900°C, the austenite is completely recrystallized, reaching the orientation density a value near 1. Precipitation of σ - phase was observed in the samples annealed at temperatures ranging from 700 to 950°C.