In this paper, a Fe-Mn-Al-C austenitic steel with certain addition of Cr and N alloy was used as experimental material. By using the SETSYS Evolution synchronous differential thermal analysis apparatus, the scanning e...In this paper, a Fe-Mn-Al-C austenitic steel with certain addition of Cr and N alloy was used as experimental material. By using the SETSYS Evolution synchronous differential thermal analysis apparatus, the scanning electron microscope （SEM）, the electron microprobe （EPMA） and the X-ray diffraction （XRD）, the high-temperature oxidation behavior microstructure and the phase compositions of this steel in air at 600-1,000 ℃ for 8 h have been studied. The results show that in the whole oxidation temperature range, there are three distinct stages in the mass gain curves at temperature higher than 800 ℃ and the oxidation process can be divided into two stages at temperature lower than 800 ℃. At the earlier stage the gain rate of the weight oxidized in temperature range of 850 ℃ to 1,000 ℃ are extremely lower. The oxidation products having different surface microstructures and phase compositions were produced in oxidation reaction at different temperatures. The phase compositions of oxide scale formed at 1,000 ℃ are composed of Fe and Mn oxide without Cr. However, protective film of Cr oxide with complicated structure can be formed when the oxidation temperature is lower than 800 ℃.展开更多
Based on the rigid-plastic finite element method（FEM）, the shear stress field of deformation region for high manganese austenite steel during hot asymmetrical rolling process was analyzed. The influences of rolling ...Based on the rigid-plastic finite element method（FEM）, the shear stress field of deformation region for high manganese austenite steel during hot asymmetrical rolling process was analyzed. The influences of rolling parameters, such as the velocity ratio of upper to lower rolls, the initial temperature of workpiece and the reduction rate, on the shear deformation of three nodes in the upper, center and lower layers were discussed. As the rolling parameters change, distinct shear deformation appears in the upper and lower layers, but the shear deformation in the center layer appears only when the velocity ratio is more than 1.00, and the absolute value of the shear stress in this layer is changed with rolling parameters. A mathematical model which reflected the change of the maximal absolute shear stress for the center layer was established, by which the maximal absolute shear stress for the center layer can be easily calculated and the appropriate rolling technology can be designed.展开更多
基金supported by the National High Technology Research and Development Program of China (No. 2012AA03A508)the National Natural Science Foundation of China (No. 51271051)
文摘In this paper, a Fe-Mn-Al-C austenitic steel with certain addition of Cr and N alloy was used as experimental material. By using the SETSYS Evolution synchronous differential thermal analysis apparatus, the scanning electron microscope （SEM）, the electron microprobe （EPMA） and the X-ray diffraction （XRD）, the high-temperature oxidation behavior microstructure and the phase compositions of this steel in air at 600-1,000 ℃ for 8 h have been studied. The results show that in the whole oxidation temperature range, there are three distinct stages in the mass gain curves at temperature higher than 800 ℃ and the oxidation process can be divided into two stages at temperature lower than 800 ℃. At the earlier stage the gain rate of the weight oxidized in temperature range of 850 ℃ to 1,000 ℃ are extremely lower. The oxidation products having different surface microstructures and phase compositions were produced in oxidation reaction at different temperatures. The phase compositions of oxide scale formed at 1,000 ℃ are composed of Fe and Mn oxide without Cr. However, protective film of Cr oxide with complicated structure can be formed when the oxidation temperature is lower than 800 ℃.
基金Item Sponsored by National Natural Science Foundation of China(51274062)
文摘Based on the rigid-plastic finite element method（FEM）, the shear stress field of deformation region for high manganese austenite steel during hot asymmetrical rolling process was analyzed. The influences of rolling parameters, such as the velocity ratio of upper to lower rolls, the initial temperature of workpiece and the reduction rate, on the shear deformation of three nodes in the upper, center and lower layers were discussed. As the rolling parameters change, distinct shear deformation appears in the upper and lower layers, but the shear deformation in the center layer appears only when the velocity ratio is more than 1.00, and the absolute value of the shear stress in this layer is changed with rolling parameters. A mathematical model which reflected the change of the maximal absolute shear stress for the center layer was established, by which the maximal absolute shear stress for the center layer can be easily calculated and the appropriate rolling technology can be designed.
