摘要
Microstructures of casting samples of Fe-9%Cr steel and samples subjected to different heat treatments were investigated to determine their formation and evolution mechanism. The results show that there is no macroscopic segregation in the casting Fe-9%Cr steel. During cooling from solidification temperature to room temperature, 6-ferrite → austenite transformation is obviously influenced by cooling rate, while subsequent transformation of austenite does not obviously depend on the cooling rate. In the casting; samples, a great number of precipitates distribute inside martensitic laths while there are almost no precipitates inside δ-ferrite. When the casting samples were reheated to and isothermally held at 800 ℃, the original precipitates and the lath boundaries disappeared gradually. Meanwhile, new precipitates nucleate and grow at the prior lath boundaries.
Microstructures of casting samples of Fe-9%Cr steel and samples subjected to different heat treatments were investigated to determine their formation and evolution mechanism. The results show that there is no macroscopic segregation in the casting Fe-9%Cr steel. During cooling from solidification temperature to room temperature, 6-ferrite → austenite transformation is obviously influenced by cooling rate, while subsequent transformation of austenite does not obviously depend on the cooling rate. In the casting; samples, a great number of precipitates distribute inside martensitic laths while there are almost no precipitates inside δ-ferrite. When the casting samples were reheated to and isothermally held at 800 ℃, the original precipitates and the lath boundaries disappeared gradually. Meanwhile, new precipitates nucleate and grow at the prior lath boundaries.
基金
supported by the National Magnetic Confinement Fusion Program (No. 2011GB108002)
the National Natural Science Foundation of China (No. 51071021)
