Kinetics of the precipitation and the structure of dispersed phases in hot-worked austenite

Abstract

1. We investigated the kinetics of precipitation and the characteristic changes in the structure of dispersed phases in steel of the Kh18N10T type in the process of postdeformation holding. It was found that the dispersed phases consist of titanium carbonitride, carbide of the M6C type, and intermetallic χ and σ phases. 2. Deformation promotes formation of particles of excess phase of small size and accelerates the precipitation process: The holding time for intensive precipitation is shorter in deformed than in undeformed austenite. 3. Precipitation of excess phases inhibits not only recrystallization but also softening in the prerecrystallization but also softening in the prerecrystallization stage; there is even a slight increase in the hardness of austenite — precipitation hardening. 4. Oriented acicular precipitates inhibit all stages of recrystallization much more than equiaxed precipitates of rounded form. 5. We determined the effect of titanium as a strong carbide-forming element on the kinetics of recrystallization: The beginning of recrystallization in the steel with titanium is delayed more than 30 times at 900° and 15 times at 1000°.