Age-Hardening Behavior in High-Nitrogen Stable Austenitic Stainless Steel

抄録

Age hardening in stable austenitic stainless steel wires with a chemical composition of Fe–18%Cr–12%Ni and different N contents was investigated to clarify the role of N. Age hardening could be enhanced by increasing the drawing ratio and N content. The highest age-hardening effect was observed at 800 K in the N-bearing specimens. In addition, severe drawing induced low-temperature age hardening at 450–600 K. Differential scanning calorimetry (DSC) analysis revealed that age hardening at 800 K may be attributed to particle dispersion strengthening by Cr₂N. Meanwhile, the exothermic peaks observed at 450–600 K were controlled by the pipe diffusion of N. However, nitride precipitates and clusters could not be detected by 3D atom probe analysis, which implies the formation of atomic-scale N products, such as I-S pairs, at the dislocations.

 

This Paper was Originally Published in Japanese in J. Jpn. Soc. Heat Treat. 61 (2021) 112–118. Result and Discussion are slightly modified.

Fig. 2 Variation in hardness as a function of aging temperature in solution-treated and 30%, 50%, and 80% cold-drawn 0.2N steel aged at different temperatures for 1.8 ks.