Study on Precipitation in 1Cr22Mnl5N Stainless Steel

摘要

Influence of temperature and time on precipitation of nitrides and carbides, which occurs in solution treatment and aging process of 1Cr22Mnl5N stainless steel, was investigated by the use of metallography and electron microscopy analysis. The results show that Cr_(23)C_6 precipitates in 1Cr22Mnl5N stainless steel, growing from grain boundaries into intragrain, show various morphologies in the investigated temperature range, including granular-like, worm-like, layer by layer and chrysanthemum-like. In contrast, a-phase precipitates are just granular-like particles. The corresponding isothermal precipitation kinetics curves of nitrides and carbides have been measured respectively. The nose-top temperature for Cr_(23)C_6 precipitation is about 850℃ with incubation time of 90～ 120 s. Precipitates were seldom observed over 950X3 or when the cooling rate is higher than 3.3℃ /s. Most of precipitates are Cr_(23)C_6. With the increasing ageing time, the size and volume fraction of Cr_(23)C_6 precipitates increases and a small amount of σ-phase also starts to precipitate out. Nitrogen is either to form Cr_(23)(C,N)_6 and or solute in matrix as supersaturated interstitial atoms.