Work

Precipitation behavior of the Cr23C6 and Cr2(C, N) phase within the medium-nitrogen austenitic stainless steel and its mechanism of induced formation of thin film at grain boundaries

Year: 2026

Type: article

Abstract: In the global shortage of nickel resources, it is imperative to optimize the production process of nickel-saving stainless steel and further improve the quality of its products. Among the various types of nickel-saving stainless steel, Cr-Mn-N stainless steel has the widest application range. This study investigates a novel as-rolled medium-nitrogen austenitic stainless steel (A-ss-N). Annealing treatments were conducted at 800℃, 850°C, 900℃, and 1000℃ for 30 minutes. The microstructures of as-rolled and heat-treated A-ss-N were characterized, its tensile properties were tested. Results demonstrate that annealing at 800°C/850°C for 30 minutes induces substantial precipitation of granular Cr23C6 and Cr2(C, N) precipitates at grain boundaries. The low intragranular Cr content facilitates nucleation and growth of Cr-rich thin films adjacent to these precipitates, forming interconnected thin film along grain boundaries that develop into continuous network structures. However, annealing at 900°C/1000°C for 30 minutes eliminates the thin film, while Cr23C6 and Cr2(C, N) precipitates gradually dissolve. Mechanical tests indicate that after 900°C annealing to eliminate the network structure, the room-temperature tensile properties of A-ss-N were significantly enhanced, with its elongation increasing from 29.5% to 67.5%, and the strength-ductility product improving from 23.01 GPa·% to 61.56 GPa·%.

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2026.04.140