The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz<= f<=25000 Hz and 0.1 T< =Bm <=1.0 T for three main original magnetic states in five sorts of Fe-base...The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz<= f<=25000 Hz and 0.1 T< =Bm <=1.0 T for three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys. The measured and calculated results showed that the total power loss per cycle clearly exhibited a nonlinear behavior in the range below 3 kHz～5 kHz depending on both the magnetic state and the value of Dm, whereas it showed a quasi-linear behavior above this range. The total loss was decomposed into hysteresis loss, classical eddy current loss and excess loss, the obvious nonlinear behavior has been confirmed to be completely determined by the dependence of the excess loss on frequency. It has been indicated that the change rate of the excess loss per cycle with respect to frequency sharp decreases with increasing frequency in the range below about 3 kHz～5 kHz, wherease the rate of change slowly varies above this range, thus leading to the quasilinear behavior of the total loss per cycle. In this paper, some linear expressions of the total loss per cycle has been given in a wider medium-frequency segment, which can be used for roughly estimating the total loss.展开更多
In order to increase the reaction rates between the molten steel and the slag and cut down the reduction time when the top slag of manganese ore is added into the molten steel,a method of directly alloying manganese o...In order to increase the reaction rates between the molten steel and the slag and cut down the reduction time when the top slag of manganese ore is added into the molten steel,a method of directly alloying manganese ore has been experimented in a 500-kg induction furnace.The results show that the manganese yield is greater than 90%when the wire feeding method is used.The manganese yield is 43.26%within 1 min.In contrast,the manganese yield for the top-slag adding process is only 10.98%for the same duration.The mass transfer rate of the manganese is greater in the molten steel than in the slag,and the limiting factor is the mass transfer rate of the manganese in the slag in the period of 10-30 min.The slag composition area is closer to the area of high melting point for the wire feeding method than for the top-slag adding process.During the slagging process,refining slag composed of C a O and SiO:is formed after 15 min;after 25-30 min,refining slag with a high basicity is formed and consists of CaO,SiO2 and Al203.展开更多
文摘The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz<= f<=25000 Hz and 0.1 T< =Bm <=1.0 T for three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys. The measured and calculated results showed that the total power loss per cycle clearly exhibited a nonlinear behavior in the range below 3 kHz～5 kHz depending on both the magnetic state and the value of Dm, whereas it showed a quasi-linear behavior above this range. The total loss was decomposed into hysteresis loss, classical eddy current loss and excess loss, the obvious nonlinear behavior has been confirmed to be completely determined by the dependence of the excess loss on frequency. It has been indicated that the change rate of the excess loss per cycle with respect to frequency sharp decreases with increasing frequency in the range below about 3 kHz～5 kHz, wherease the rate of change slowly varies above this range, thus leading to the quasilinear behavior of the total loss per cycle. In this paper, some linear expressions of the total loss per cycle has been given in a wider medium-frequency segment, which can be used for roughly estimating the total loss.
基金This research has been financially supported by the National Key R&D Program(2017YFB0304000)the Beijing Natural Science Foundation(2172057)in China+1 种基金the State Key Laboratory of Refractories and Metallurgy Foundation(G201804)the National Natural Science Foundation of China(51704080,51874102).
文摘In order to increase the reaction rates between the molten steel and the slag and cut down the reduction time when the top slag of manganese ore is added into the molten steel,a method of directly alloying manganese ore has been experimented in a 500-kg induction furnace.The results show that the manganese yield is greater than 90%when the wire feeding method is used.The manganese yield is 43.26%within 1 min.In contrast,the manganese yield for the top-slag adding process is only 10.98%for the same duration.The mass transfer rate of the manganese is greater in the molten steel than in the slag,and the limiting factor is the mass transfer rate of the manganese in the slag in the period of 10-30 min.The slag composition area is closer to the area of high melting point for the wire feeding method than for the top-slag adding process.During the slagging process,refining slag composed of C a O and SiO:is formed after 15 min;after 25-30 min,refining slag with a high basicity is formed and consists of CaO,SiO2 and Al203.
文摘在低碳钢表面采用明弧堆焊的方法制备了不同氮含量的Fe-Cr-C-B-N系堆焊合金.借助X射线衍射仪(XRD)、光学显微镜(OM)、扫描电子显微镜(SEM)、洛氏硬度计和湿砂磨损试验机对堆焊层的组织和性能进行分析.结果表明,堆焊层的显微组织为马氏体+奥氏体+BN+M23(C,B)6+M3(C,B)+M2B.随着氮添加量的增多,组织中有BN生成,初生奥氏体向针状马氏体转变,枝晶间共晶组织的数量减少;堆焊层硬度增加,磨损量出现先减少后增加的趋势.当堆焊层中氮的含量为0.17%时,基体组织与硬质相之间匹配良好,堆焊层的综合性能达到最佳,其硬度值为62.7 HRC,而磨损量仅为0.054 2 g.
