Effect of nitrogen on the phase composition and physical and mechanical properties of stainless austenitic-pearlitic steels

1. Being an austenite-forming element, nitrogen (up to 0.36%) hardens austenite into austenitic-ferritic steels, but significantly reduces the amount of ferrite — from 65 to 35%. The overall effect of this influence of nitrogen is to reduce the strength properties of the steels under investigation. 2. A reduction in the amount of α-phase in the structure of dual-phase steels with the introduction of nitrogen is accompanied by pronounced enrichment of the ferrite with ferrite-forming elements, primarily with chromium and molybdenum, and its impoverishment with austenite-forming elements. This contributes to the formation of σ-phase, which leads to embrittlement of the steel.