Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the co...Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.展开更多
Solidification structure is critical in the control of the mechanical properties and quality during the continuous casting process. The thermo-physical properties of 13 Cr steel added some rare metals, such as Mo, V, ...Solidification structure is critical in the control of the mechanical properties and quality during the continuous casting process. The thermo-physical properties of 13 Cr steel added some rare metals, such as Mo, V, Nb, are measured to better understand the solidification structure of 13 Cr bloom. A computational model using CA-FE(cellular automation-finite element) method coupled with heat transfer model is developed to describe the solidification structure in continuous casting process. It is found that the calculated solidification structure is in good agreement with the observed data. The influence of casting speed and superheat on the solidification structure of the bloom is studied in detail. In order to obtain more equiaxed crystal ratio and low degree of the segregation in the bloom, the optimized casting speed 0.6 m/min and superheat less than 25 °C are determined for the caster. Using the optimized manufacturing parameters, these samples are 60% with the equiaxed zone ratio of 8%–10% and below the degree of segregation 1.05.展开更多
基金Project(50474083) supported by the National Natural Science Foundation of ChinaProject supported by the Baoshan Iron & Steel Co. Ltd. of China
文摘Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.
基金Projects(51274057,51474057) supported by the National Natural Science Foundation of ChinaProject(2012AA03A508) supported by the High-tech Research and Development Program of China
文摘Solidification structure is critical in the control of the mechanical properties and quality during the continuous casting process. The thermo-physical properties of 13 Cr steel added some rare metals, such as Mo, V, Nb, are measured to better understand the solidification structure of 13 Cr bloom. A computational model using CA-FE(cellular automation-finite element) method coupled with heat transfer model is developed to describe the solidification structure in continuous casting process. It is found that the calculated solidification structure is in good agreement with the observed data. The influence of casting speed and superheat on the solidification structure of the bloom is studied in detail. In order to obtain more equiaxed crystal ratio and low degree of the segregation in the bloom, the optimized casting speed 0.6 m/min and superheat less than 25 °C are determined for the caster. Using the optimized manufacturing parameters, these samples are 60% with the equiaxed zone ratio of 8%–10% and below the degree of segregation 1.05.
