2019 Pittsburgh AISTech

Study on Phase Transition and Precipitation Behavior of FeCrAl Stainless Steel During Equilibrium Solidification (Room 412)

08 May 19
8:00 AM - 8:30 AM

Tracks: Metallurgy - Processing, Products & Applications

Speaker(s): Zhenqiang Deng, University of Toronto; Jianhua Liu, University of Science & Technology Beijing; Yindong Yang, University of Toronto; Alexander McLean, University of Toronto; Yang He, University of Science & Technology Beijing

The phase transitions and precipitation behavior of FeCrAl stainless steel during equilibrium solidification and cooling were studied using phase diagrams derived from Factsage calculations together with results from thermal expansion experiments. Based on the Factsage calculations, the following phase transformations were confirmed: Liquid→α→α+(Fe,Cr)7C3→α+(Fe, Cr)23C6 → α+α’+(Fe, Cr)23C6 with no transformation of ferrite to austenite. The expansion test results agree with the phase fraction diagrams. The average linear expansion coefficient of FeCrAl alloy is decreased by the presence of the α' phase and increased by the precipitation of (Fe, Cr)23C6. According to the vertical sections and isothermal cross-sectional graphs, (Fe, Cr)7C3 can only precipitate if the C content is high enough during solidification. A decrease in Al content or an increase in Cr content can reduce the phase stability range of (Fe, Cr)7C3 and increase the temperature for the precipitation of (Fe, Cr)23C6.