The thirteen mother alloys,C%+1/3Si%=4.45%,differing in their Si,Ce,Sb and Sn contents,were prepared.Seventy grams of these alloys was remelted in a high purity alumina crucible at 1,450oC under an Ar atmosphere,and t...The thirteen mother alloys,C%+1/3Si%=4.45%,differing in their Si,Ce,Sb and Sn contents,were prepared.Seventy grams of these alloys was remelted in a high purity alumina crucible at 1,450oC under an Ar atmosphere,and then cooled at 30 K/min for obtaining their cooling curves.Their graphite morphologies were observed using an optical microscope and an SEM.Their three-dimensional graphite shapes were observed by the SEM using the samples whose matrices were etched off with an acid-aqua solution,to confirm the chunky graphite.For discussing the influence of the Si and Ce contents on the chunky graphite formation,two experiments were carried out.In the first one,the Si contents were changed from 0 to 4% in the 0.15%Ce alloys,and for the second one,the 3.5%Si and 4%Si samples that differed in the Ce contents of 0.1 and 0.2% were used.In the third experiment,the influence of Sb and Sn on the chunky graphite formation was investigated by using the 4%Si and 0.1%Ce samples.The results showed that with the increase of the Si content,the volume fraction of the chunky graphite increases,while the volume fraction of the ledeburite decreases,and the chunky graphite volume fraction in the 0.2%Ce samples is higher than that of the 0.1%Ce samples.The effect of the Sb and Sn additions on the prevention of chunky graphite formation cannot be confirmed due to their high Si contents.Therefore,further studies will be needed in this field.展开更多
Applied technologies of magnetohydrodynamics(MHD)have been widely used in steelmaking based on their characteristics of clean and remote control of liquid metal.Generally,phenomena are quite complex and coupled among ...Applied technologies of magnetohydrodynamics(MHD)have been widely used in steelmaking based on their characteristics of clean and remote control of liquid metal.Generally,phenomena are quite complex and coupled among hydrodynamics,electromagnetism and thermodynamics,so numerical simulations play important roles in various applications of MHD for equipments design and control parameters decision.In the simulation,it is preferable to use one package calculation rather than coupled analyses such as the one between finite element method(FEM)and finite difference method(FDM)with the data conversion caused by different schemes.For the resolution,a three-dimensional finite volume approach for MHD is established based on scalar and vector potential and magnetic induction equation treated as transport equations.In this paper,results of the analyses of various MHD phenomena in EPM application to steelmaking process are described with some examples such as plasma heating and electromagnetic flow control tools.展开更多
Removal of non-metallic inclusions in molten steel is important from the viewpoint of improvement of quality, property and yield of the products. As a removal method of inclusions from molten metal, gas bubble flotati...Removal of non-metallic inclusions in molten steel is important from the viewpoint of improvement of quality, property and yield of the products. As a removal method of inclusions from molten metal, gas bubble flotation adhering inclusions is well known. Gas bubbling is particularly effective for the removal of fine inclusions. Water model experiment is reported the quantitative analysis of the removal ratio of dispersed particles removed from water by gas bubbles.展开更多
文摘The thirteen mother alloys,C%+1/3Si%=4.45%,differing in their Si,Ce,Sb and Sn contents,were prepared.Seventy grams of these alloys was remelted in a high purity alumina crucible at 1,450oC under an Ar atmosphere,and then cooled at 30 K/min for obtaining their cooling curves.Their graphite morphologies were observed using an optical microscope and an SEM.Their three-dimensional graphite shapes were observed by the SEM using the samples whose matrices were etched off with an acid-aqua solution,to confirm the chunky graphite.For discussing the influence of the Si and Ce contents on the chunky graphite formation,two experiments were carried out.In the first one,the Si contents were changed from 0 to 4% in the 0.15%Ce alloys,and for the second one,the 3.5%Si and 4%Si samples that differed in the Ce contents of 0.1 and 0.2% were used.In the third experiment,the influence of Sb and Sn on the chunky graphite formation was investigated by using the 4%Si and 0.1%Ce samples.The results showed that with the increase of the Si content,the volume fraction of the chunky graphite increases,while the volume fraction of the ledeburite decreases,and the chunky graphite volume fraction in the 0.2%Ce samples is higher than that of the 0.1%Ce samples.The effect of the Sb and Sn additions on the prevention of chunky graphite formation cannot be confirmed due to their high Si contents.Therefore,further studies will be needed in this field.
基金Part of this report provides the results of theenergy saving projects of Nippon Steel Corporation,financially supported by the Ministry of Economy,Trade and Industry of Japan
文摘Applied technologies of magnetohydrodynamics(MHD)have been widely used in steelmaking based on their characteristics of clean and remote control of liquid metal.Generally,phenomena are quite complex and coupled among hydrodynamics,electromagnetism and thermodynamics,so numerical simulations play important roles in various applications of MHD for equipments design and control parameters decision.In the simulation,it is preferable to use one package calculation rather than coupled analyses such as the one between finite element method(FEM)and finite difference method(FDM)with the data conversion caused by different schemes.For the resolution,a three-dimensional finite volume approach for MHD is established based on scalar and vector potential and magnetic induction equation treated as transport equations.In this paper,results of the analyses of various MHD phenomena in EPM application to steelmaking process are described with some examples such as plasma heating and electromagnetic flow control tools.
文摘Removal of non-metallic inclusions in molten steel is important from the viewpoint of improvement of quality, property and yield of the products. As a removal method of inclusions from molten metal, gas bubble flotation adhering inclusions is well known. Gas bubbling is particularly effective for the removal of fine inclusions. Water model experiment is reported the quantitative analysis of the removal ratio of dispersed particles removed from water by gas bubbles.
