Industrial Research on Broadening of Slab in Continuous Casting Process

 The broadening of slab was investigated on the basis of several industrial manufactures of continuous casting. The results show that slab broadening commonly exists in the process of continuous casting. It is found that there are few reports on it until now. In order to find out the reasons of slab broadening, we checked the effect of change of mold size, excepting technological parameters, conditions of soft reduction, and contraction of roll gap on slab broadening. Our examinations exclude the possibility of change of mold size, excepting technological parameters to be the causes of broadening of slab. The broadening of slab probably results from the static pressure of molten steel and the force from driving rolls. At the same time, online observations on three kinds of steel in the process of continuous casting reveal that the average objective ratio of slab broadening ranges from 1.27 % to 3.00 %, and even arrives at 4.4 %. In addition, the width of mold and formulas of calculating the broadening of slab was deduced.     

Analysis of the State of the Fine-Dispersive Precipitations in the Structure of High Strength Steel Weldox 1300 by Means of Electron Diffraction

The paper deals with investigations concerning the structure and state of dispersive precipitations of the phases consolidating in the high-strength steel Weldox 1300 after its high temperature thermomechanical treatment.Making use of transmission technique of electron microscopy (TEM) mainly the microstructure and morphology of martensite was analysed,as well as the state of dispersive precipitations of carbides and nitrides resulting from microadditives of such alloys as Nb,V,Ti or B,introduced into the steel.Observations revealed both a fine lathed and twin structure of the matrix of martensite in the investigated steel.By means of the method of electron diffraction particles of secondary strengthening phases of the M(C,N) type of a nanocrystalline size could be identified,and also non-metallic oxide inclusions,affecting the mechanism of strengthening of the investigated steel.     

High Purity Graphite And Multiple Aluminum Products Are Selected in the Key New Materials Application Demonstration List by MIIT

<正>On Dec., 26, 2018, Ministry of Industry and Information Technology released the announcement of printing and distributing Guidance List of The Application Demonstration of The First Batch of Key Materials (Version 2018). Based on the announcement, the printing and distributing of Guidance List of The Application Demonstration of The First Batch of Key Materials (Version     

Analysis Of Copper Processing Industry In China 2017

正I. Background1. Production of copper processed products and sub-varieties scores steady annual growth In 2017,the production of copper processed products in China reached 17.225 million tons,with a YoY increase of 4.5%,consisting of wire rods of 7.77 million tons,bars of 2.388 million tons, pipes of 2.6 million tons, strips of     

Effect of CaCl_2 on RDI and RI of Sinter

 On the premise of maintaining the reducibility of sinter unchanged, it is of great significance to reduce the RDI of sinter, which will improve the permeability of blast furnace burden column, so as to realize stable and smooth performance, and keep high yield and low consumption. Under laboratory conditions, a study was proposed on the RDI and RI of sinter, which was immersed with different types and concentrations of solutions. The results show that Cl- is the main factor for reducing the RDI of sinter, and the RDI and RI of sinter decrease with the increase of Cl- concentration. With comprehensive consideration of the RDI and RI of sinter, when the concentration of Cl- is 2%, the RDI of sinter will be significantly reduced and RI will not be affected. In order to study the mechanism of CaCl2 effect on the RDI and RI of sinter, analysis based on the methods of IR Spectra, SEM and chalcography was adopted.     

Effects of Roasting Pretreatment in Intense Magnetic Field on Phase Transition and Digestion Performance of Diasporic Bauxite

This paper investigates the changes of phase and apparent morphology under the combined effects of an intense magnetic field and temperature field.The effect of different roasting conditions on the digestion performance of roasted ore is also studied.The results indicate that roasting pretreatment under high magnetic fields can change the microstructure and digestion performance of bauxite.The Al phase changed faster of high iron bauxite than that of low iron bauxite.The digestion performance of low iron bauxite improved significantly through roasting pretreatment in intense magnetic field.But the digestion performance of bauxite get worse with the iron content in bauxite increase,because the high iron content of bauxite lead the shielding effect of magnetic field and make the crystal structure of bauxite stably,the surface area or low iron bauxite increased obviously during pretreatment.The optimal pretreatment condition of low iron bauxite is roasting temperature of 550℃,roasting time of 60min and magnetic field intensity of 6T,while for the high iron is roasting temperature of 500℃,roasting time of 60min and magnetic field intensity of 9T.     

Massive Mineral Reserves of Nonferrous Metals Found in Guangxi

According to news from the Department of Land and Resources of Guangxi Zhuang Autonomous Region, in 2011, more than 0.5 billion tons of mineral resources (including 127,000 tons of newly-added rare earth resources) were found in Guangxi.According to Liang Bing, vice head of the Department of Land and Resources of the autonomous region, on the basis of general     

New Regulations on Import and Export License Control Effected

On the basis of the Foreign Trade Law of thePeople's Republic of China and theRegulations on Import and Export GoodsControl of the People's Republic of China,theMinistry of Foreign Trade and EconomicCooperation(MOFTEC)and the GeneralAdministration of the Customs have recentlyissued the 2003 Catalogue of CommoditiesSubject to Import License Control and the 2003Catalogue of Commodities Subject to ExportLicense Control,which became effective onJanuary 1,2003.     

Research and Application of Tundish Casting Auto-Start Technology on Slab Casters

Based on introducing equipments and technology conditions of continuous casting plant of the 4th sub-factory of general steelmaking factory of WISCO, the operation of tundish casting auto-start, control of withdrawal straightening device drive start and control of mould level are analyzed, the critical effect of liquid level control is emphasized in this part. Through comprehensive industrial scale experiments, several relevant problems were solved in application process, which promoted the rate of auto-casting of the factory to beyond 98 percent stably from 39 at the beginning.     

Adaptive-filter technology for detecting steel-strip surface roughness

To address the shortcomings of traditional filtering methods that utilize the scattering method for the online detection of strip surface roughness and to improve the accuracy of the identification of strip surface roughness,in this paper,a regression-smoothing adaptive-filtering method was investigated for use in the online detection of surface roughness in the cold-rolled strip. The results show that by the use of robust locally weighted regression to perform noise-reduction preprocessing of the initial parameters in the online detection of surface roughness,followed by the establishment of a kernel function,the regression-smoothing adaptive-filtering method can update the weight based on the relative positions of historical and current data. When the changes in neighboring data exceed the established threshold value of 0. 75 μm,the width of the smoothing window is automatically reduced,thereby realizing adaptive variable-step regression-smoothing filtering of online roughness detection data. By the use of this regression-smoothing adaptive-filtering method,the accuracy of detecting the surface roughness of a cold-rolled strip can be improved and the requirements of downstream users better satisfied.     

Reviews and Prospects of Clean Steel Production Practices in Ansteel

It summarizes the recognition of clean steel through the reviews the historical development and production practices of clean steel of Ansteel in this paper.The technological characteristic,equipment,controlling capability and new exploratory of clean steel production of Ansteel are introduced.It has also made a new appraisal to the production line of different clean steel from the angle of high efficiency,stabilization and low-cost.The prospects of new production technology of clean steel are introduced at the end of the paper.     

INDUSTRIAL GROWTH UP 25% DURING FIRST HALF

During the first six months of 1993,theindustrial production of China wit-nessed an increase of 25.1 per cent oversame period of Iast year,the StateStatisties Bureau reported.In themonth of June,produetion ehalked lipareeord growth of 30.2 per     

Hydrogen Evolution on Binary and Ternary Cobalt Alloys Deposited With Superimposed Magnetic Field

The article presents results of electrodeposition of Co-Mo Co-Mo-C alloys in a magnetic field characterized by low overvoltage of hydrogen evolution.Addition of molybdenum and carbon was to lower the values of overvoltage of hydrogen evolution on cobalt.The influence of bath pH,bath composite,current density and magnetic field with different orientation on the deposits composition,structure and overpotential for hydrogen evolution reaction(HER)was determined.Electrocatalytic properties of the obtained alloy coatings within the range of hydrogen evolution were tested in a concentrated NaOH solution.The comparison of electrocatalytic properties of Co-Mo alloys with properties of Co-Mo-C ones enabled determining the influence of carbon presence in cathodic deposits on the overpotential values for hydrogen evolution.     

Effects of Plastic Warm Deformation on Cementite Spheroidization of a Eutectoid Steel

 The warm compression tests were performed on the eutectoid steel to investigate the evolution of cementite morphology. Several processing parameters, such as temperature, strain rate and reduction, were changed to analyze the effect of each parameter on spheroidization of cementite. The results showed that the warm compression promoted the fragmentize and the spheroidization of lamellar cementites. When the specimen was compressed with reduction of 50% at 700 ℃ and in the strain rate of 0.01 s-1, the excellent spheroidized cementite was obtained. The mechanism of fragmentation and spheroidization of lamellar cementites during compression was discussed by using transmission electron microscope. The formation of spheroidized cementite was related to the time of compression process. The fragmentize of lamellar cementites was due to the extension of sub-grain boundary in the cementite. The spheroidization of cementite depended on the diffusion of carbon atoms at the tip of bended and breakup cementite.     

Effect of Rare Earth on Microstructure of Eutectic A1-2 % Fe Alloy

Effect of La-rich rare earth on eutectic microstructure in A1-2? alloy was studied. When the addition of RE is small, a-A1 phase is in the form of cellular dendrite. With the increase of the addition of RE, the nucleation and growth of a-A1 dendrite are suppressed, and eutectic Al3Fe phase is refined.When the addition of RE gets to 0.6% (mass frac-tion), the size of eutectic Al3Fe increases. In addi-tion, mechanism of the effect of mixed RE on eutectic morphology of A1-2? alloy is explored.     

Activity model and its application in quarternary system CaO-FeO-SiO2-WO3

 The activity model of CaO-FeO-SiO2-WO3 quarternary system was established according to the coexistence theory of slag structure and the reduction thermodynamics of scheelite was discussed by applying this model. The activities of SiO2 and WO3 decrease, while that of CaO increases with increasing the basicity of slag. Among SiC, [C] and [Si] reactants, the reducing capability of SiC is the strongest, while that of [C] is the poorest at a high temperature (about 1873 K). It is advantageous to increase the yield of tungsten by increasing the content of [Si] or [C]. Oxidizability of slag has a significant effect on the yield of tungsten. Controlling of basicity and oxidizability of slag can prevent the oxidation loss of tungsten.     

Simulation of Thermodynamics and Kinetics for KR Desulphurization

This paper seeks to optimize parameters, reduce the cost of desulphurization and the consumption of operation about KR pretreatment of hot metal at the Stainless Steel Company, Baosteel Group. Based on the theoretical analysis of physical chemistry in metallurgy, simulation experiments of the KR desulphurization of hot metal were conducted in a laboratory and the composition of the desulphurization was optimized, by means of chemical analysis, DSC, SEM and EDS. The water modeling displays the fluid flow characteristics of KR desulphurization. Combination of the techniques and production at the Stainless Steel Company, Baosteel Group, the optimized parameters of the process are put forward.     

TEM Analysis on YBCO Composited Superconducting Tapes

The microstructures of the YBCO composited superconducting tapes with different J_c were analysed byTEM.The relationship between microstructure and J_c of the tapes is discussed in detail.It is demonstrated thatJ_c value of the tapes increases significantly with the decrease in the width of grain boundary,increase of the twindensity and the reducing of the amount of precipitates at grain boundary.At grain boundary of the tapes,howev-er,small amount of non-superconducting phases can-not be avoided.For the fabrication of high J_c YBCO com-posited tapes,it is very important to improve the microstructure of the superconductor perfectly.     

Electrochemical formation of Mg-Li-Y alloys by co-deposition of magnesium, lithium and yttrium ions in molten chlorides

An electrochemical approach for the preparation of Mg-Li-Y alloys via co-reduction of Mg, Li, and Y on a molybdenum electrode in LiCl-KCl-MgCl2-YCl3 melts at 943 K was investigated. Cyclic voltammograms (CVs) illuminated that the underpotential deposition (UPD) of yttrium on pre-deposited magnesium led to the formation of a liquid Mg-Y alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Y led to the formation of a liquid Mg-Li-Y alloy. Chronopotentiometry measurements indicated that the order of electrode reactions was as follows: discharge of Mg(II) to Mg-metal, electroreduction of Y on the surface of Mg with formation of ε-Mg24+xY5 and after that the discharge of Li+ with the deposition of Mg-Li-Y alloys. X-ray diffraction (XRD) indicated that Mg-Li-Y alloys with different phases were formed via galvanostatic electrolysis. The microstructure of different phases of Mg-Li-Y alloys was characterized by optical microscope (OM) and scanning electron microscopy (SEM). The analysis results of inductively coupled plasma atomic emission spectrometer (ICP-AES) showed that the chemical compositions of Mg-Li-Y alloys corresponded with the phase structures of the XRD patterns, and the lithium and yttrium contents of Mg-Li-Y alloys depended on the concentrations of MgCl2 and YCl3 .     

Microstructure Refinement and Precipitation Characteristics of TMCP-Processed Plates for Pipeline Applications

The influence of technological parameters of controlled rolling and accelerated cooling (TMCP-processing) on microstructure and mechanical properties of plates with thickness of 25 mm and more at the mill "5000" of OJSC "Мagnitogorsk Iron and Steel Works" were investigated.The necessity of formation of fine-grained ferrite-bainite microstructure without elongated areas of coarse lath bainite for achievement of DWTT properties is proved.Precipitation conditions and type of Nb(C,N) and (Nb,V)(C,N) particles with the size of less than 10 nm in the process of rolling and additional tempering are defined.