The growth dynamics of austenite grain was investigated in steel 9Cr2 Mo with different rare earth(RE)element addition.The results show that austenite grains of steel 9Cr2 Mo can be refined and their growth can be res...The growth dynamics of austenite grain was investigated in steel 9Cr2 Mo with different rare earth(RE)element addition.The results show that austenite grains of steel 9Cr2 Mo can be refined and their growth can be restrained by adding a certain amount of RE.According to the results,the n and Q were calculated and the mechanism of the refinement of austenite grains was discussed.展开更多
The intergranular cracking of 9% Ni cast steel seems mainly to relate to the segregation of contaminates H,S and P along boundaries.An addition of rare earth may eliminate the seg- regation of these contaminates along...The intergranular cracking of 9% Ni cast steel seems mainly to relate to the segregation of contaminates H,S and P along boundaries.An addition of rare earth may eliminate the seg- regation of these contaminates along grain boundaries and improve the binding force among boundaries,so as to reduce remarkably the intergranular cracking.展开更多
The microstructure, composition and shape of precipitated phase under as-cast and finished product state of 5Cr21Mn9Ni4N steel with different rare earth （RE） amount were studied. Mechanical properties of 5Cr21Mn9Ni4...The microstructure, composition and shape of precipitated phase under as-cast and finished product state of 5Cr21Mn9Ni4N steel with different rare earth （RE） amount were studied. Mechanical properties of 5Cr21Mn9Ni4N steels withont RE addition and with RE added by 0. 2% in mass percent were tested respectively. The results indicate that the solid solution amount of RE is about 10^-6 -10^-5 order of magnitude in 5Cr21Mn9Ni4N steel. Dendrite of as-cast condition is refined obviously and dimension of interstitial phase is shortened when RE is added by 0.10%-0.20%. But the microstructure will be coarser if surplus RE is added. Precipitated phase under finished product state distributes evenly in nearly same size with RE added by 0. 2% which leads to a largely improved high temperature mechanical property.展开更多
The oxidation resistance of 5Cr21Mn9Ni4N steel micro-alloying by RE at 700 - 900 ℃ was investigated. The results indicate that oxidation exponent n and oxidation activation energy are increased, and oxidation velocit...The oxidation resistance of 5Cr21Mn9Ni4N steel micro-alloying by RE at 700 - 900 ℃ was investigated. The results indicate that oxidation exponent n and oxidation activation energy are increased, and oxidation velocity constant kp is decreased when 0.2% RE is added in 5Cr21Mn9Ni4N steel. The addition of RE elements does not alter phase constitution of oxidation scale, however it improves the configuration of oxidation scale, and increases thermal stability and adhesivity of oxidation scale, which results in the raise of oxidation resistance of 5Cr21Mn9Ni4N steel at high temperature. The oxidation scale constitutes of refractory steel transfer from manganic oxide mostly to ferric oxide mostly with the increase of temperature, which leads to descend of compactness and desquamation resistance of oxidation scale. The mass increase of ferric oxide in the oxidation scale and the looseness of oxidation scale are the main reason to descend the oxidation resistance of refractory steel.展开更多
文摘The growth dynamics of austenite grain was investigated in steel 9Cr2 Mo with different rare earth(RE)element addition.The results show that austenite grains of steel 9Cr2 Mo can be refined and their growth can be restrained by adding a certain amount of RE.According to the results,the n and Q were calculated and the mechanism of the refinement of austenite grains was discussed.
文摘The intergranular cracking of 9% Ni cast steel seems mainly to relate to the segregation of contaminates H,S and P along boundaries.An addition of rare earth may eliminate the seg- regation of these contaminates along grain boundaries and improve the binding force among boundaries,so as to reduce remarkably the intergranular cracking.
文摘The microstructure, composition and shape of precipitated phase under as-cast and finished product state of 5Cr21Mn9Ni4N steel with different rare earth （RE） amount were studied. Mechanical properties of 5Cr21Mn9Ni4N steels withont RE addition and with RE added by 0. 2% in mass percent were tested respectively. The results indicate that the solid solution amount of RE is about 10^-6 -10^-5 order of magnitude in 5Cr21Mn9Ni4N steel. Dendrite of as-cast condition is refined obviously and dimension of interstitial phase is shortened when RE is added by 0.10%-0.20%. But the microstructure will be coarser if surplus RE is added. Precipitated phase under finished product state distributes evenly in nearly same size with RE added by 0. 2% which leads to a largely improved high temperature mechanical property.
文摘The oxidation resistance of 5Cr21Mn9Ni4N steel micro-alloying by RE at 700 - 900 ℃ was investigated. The results indicate that oxidation exponent n and oxidation activation energy are increased, and oxidation velocity constant kp is decreased when 0.2% RE is added in 5Cr21Mn9Ni4N steel. The addition of RE elements does not alter phase constitution of oxidation scale, however it improves the configuration of oxidation scale, and increases thermal stability and adhesivity of oxidation scale, which results in the raise of oxidation resistance of 5Cr21Mn9Ni4N steel at high temperature. The oxidation scale constitutes of refractory steel transfer from manganic oxide mostly to ferric oxide mostly with the increase of temperature, which leads to descend of compactness and desquamation resistance of oxidation scale. The mass increase of ferric oxide in the oxidation scale and the looseness of oxidation scale are the main reason to descend the oxidation resistance of refractory steel.
