Rapid solidification is regarded as being an effective method to refine the microstructure and reduce or eliminate the segregation of alloying elements.In this study the microstructures of rapid solidified carbon stee...Rapid solidification is regarded as being an effective method to refine the microstructure and reduce or eliminate the segregation of alloying elements.In this study the microstructures of rapid solidified carbon steel droplets (cooled in silicone oil) with different C contents by drop tube processing were observed.The volumes of droplets were set to be 2 mm×2 mm×2 mm (TM) and 5 mm×5 mm×5 mm (FM).For most samples,the microstructures are nearly the same from the surface to the center region.The microstructures of the FM samples with higher C content are much finer than those of the TM samples,which is the opposite of the situation with the lower C content samples.The distribution of C along the diameter of each sample was detected.The segregation of C was observed in TM samples with higher C contents while not in FM samples.This is regarded as relating to recalescence and the diffusion of C atoms during the solidification process.展开更多
Low carbon steels with B and P additions were remelted by electromagnetic levitation and solidified in a vacuum drop tube. The droplet volumes were set to be 2 mm × 2 mm ×2 mm （TM） and 5 mm ×5 mm×...Low carbon steels with B and P additions were remelted by electromagnetic levitation and solidified in a vacuum drop tube. The droplet volumes were set to be 2 mm × 2 mm ×2 mm （TM） and 5 mm ×5 mm× 5 mm （FM）, respectively. The microstructure of rapidly solidified steel droplets （cooled in silicon oil） with P and both B and P addition was observed. The microstructures of B-bearing droplet samples were more uniform than those of B-free ones, for both TM and FM samples. The distribution of C and P along the diameter of each sample was detected. The well-distribution of C and P was detected in B-bearing droplet samples. So it could be deduced that B was also well distributed in the steels. It was B atoms that promoted the well-distribution of C and P, which further improved the uniformity of microstructure under the condition of rapid solidification. The micro-hardness of B- bearing samples was higher than that of B-free samples, and the hardening mechanism was discussed in detail.展开更多
Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in st...Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in steel plants, a novel approach to the recycle of CO2 separated from converter off-gas or other off-gas for the green slag splashing technique was developed, and the CO2 equilibrium conversion ratio of the green CO2 slag splashing under different technological conditions was calculated by the program of enthalpy （H）, entropy （S）, and heat capacity （C）, i.e. HSC software. Furthermore, the experiments of CO2 injected into molten converter slag were carried out, and the influencing factors of the green slag splashing technique using CO2 were analyzed. The experimental results showed that the carbon content for smooth slag splashing using COs was about 4.0%.展开更多
基金financially supported by the National Natural Science Foundation of China,Project No.51074210
文摘Rapid solidification is regarded as being an effective method to refine the microstructure and reduce or eliminate the segregation of alloying elements.In this study the microstructures of rapid solidified carbon steel droplets (cooled in silicone oil) with different C contents by drop tube processing were observed.The volumes of droplets were set to be 2 mm×2 mm×2 mm (TM) and 5 mm×5 mm×5 mm (FM).For most samples,the microstructures are nearly the same from the surface to the center region.The microstructures of the FM samples with higher C content are much finer than those of the TM samples,which is the opposite of the situation with the lower C content samples.The distribution of C along the diameter of each sample was detected.The segregation of C was observed in TM samples with higher C contents while not in FM samples.This is regarded as relating to recalescence and the diffusion of C atoms during the solidification process.
基金the National Natural Science Foundation of China (No.51074210)the Open Foundation of Key Laboratory of Materials Forming and Microstructure & Properties Control,Colleges and Universities in Liaoning Province (USTLKL2012-01)
文摘Low carbon steels with B and P additions were remelted by electromagnetic levitation and solidified in a vacuum drop tube. The droplet volumes were set to be 2 mm × 2 mm ×2 mm （TM） and 5 mm ×5 mm× 5 mm （FM）, respectively. The microstructure of rapidly solidified steel droplets （cooled in silicon oil） with P and both B and P addition was observed. The microstructures of B-bearing droplet samples were more uniform than those of B-free ones, for both TM and FM samples. The distribution of C and P along the diameter of each sample was detected. The well-distribution of C and P was detected in B-bearing droplet samples. So it could be deduced that B was also well distributed in the steels. It was B atoms that promoted the well-distribution of C and P, which further improved the uniformity of microstructure under the condition of rapid solidification. The micro-hardness of B- bearing samples was higher than that of B-free samples, and the hardening mechanism was discussed in detail.
基金Sponsored by Science and Technology Plan Projects of Tianjin of China(07ZCKFGX03800)Science and Technology Plan Projects for CAS Supporting Tianjin Construction of China(TJZX1-YW-09)
文摘Converter off-gas, an important energy resource for steel industries, is one of the weak points in the recov ery and utilization of secondary energy resources. To improve the level of recycling converter off-gas in steel plants, a novel approach to the recycle of CO2 separated from converter off-gas or other off-gas for the green slag splashing technique was developed, and the CO2 equilibrium conversion ratio of the green CO2 slag splashing under different technological conditions was calculated by the program of enthalpy （H）, entropy （S）, and heat capacity （C）, i.e. HSC software. Furthermore, the experiments of CO2 injected into molten converter slag were carried out, and the influencing factors of the green slag splashing technique using CO2 were analyzed. The experimental results showed that the carbon content for smooth slag splashing using COs was about 4.0%.
