Abstract: By optical microscopic analysis, electron probs micro-analysis and M?ssbauer effect, the existing state of Mgo and its effecf on the properties of sinter and pellet were studied, from optical microscopic observation, it was shown that as the Mgo content in sinter increased, the content of hematite and calciumferrite obviously decreased, when it reached more than 4%, some magnesiosilicate salt minerals in sinter slag was occured It was also found by electron probe micro-analysis that the Mgo mainly presented in iron oxide compound except hematite,such as magnesiomagnetite in sinter and magnesioferrite in pellet, and a small part of Mgo existed in slag phase. Large amount of Mg2+ entered in octahedron sites of magnetite of pellet of Hangchow stael works during induration period has been examined by use of Mossbausr effect which was ascertaind the mechanism of Mgo concentrated into iron oxide compound and changed the mineral constitasnts of iron ore agglomerates from avove investigation the effect of Mgo on the metallurgical properties of iron ore agglomerates was abtained.
Abstract: A one-dimensional mathematical modei was developed for describing a moving bed reactor in which iron oxide pellets are reduced to me ta 1 lie iron with hydrogen and/or carbon monoxide in a counter-current flow a-rrangement.The model uses the "three-interface shringking core model" as the expression of single-pellet reaction kinetics.The model consists of the reaction rate equations of iron oxides and the heat and mass balance equations for both of the gas and the solid streams.The model shows the longitudinal distribution of the process variables such as degree of pellets recuction,and composition,pressure as well as temperature of the gas stream. For the purpose of investigating the reduction process of pellets in a moving bed and checking the correctness of the model, a bench-scale moving bed reactor was established. The experiments were carrieb out until the steady state was reached.The calculating results based on the model s-how reasonable agreement with the experimental measurements.The model can be used for describing an industrial shaft furnace,and shows a difference characteristic between the reduction process of iron ore in a shaft furnace and the reduction process of iron ore under fixed conditions in laboratory.
Abstract: In practice using sand open risers and pouring hot molten metal into it once or twice every 20~25 minutes after pouring to compensate the volume contraction of spheroidal graphite cast iron rolls is very common.This method consumes a large quantity of metal for riser which is about 15% of the gross weight of the rolls.In order to save metal and to improve the quality of the upper edge of the roll barrel, we make use of the riser covered with Al-exothermic compound, in combination with insulating sleeve instead of previous procedure in which straw-ash heat insulator was used to cover the dry-sand open riser.The results of experiment show;that the eutectic transformation time of spheroidal graphite cast iron elongates by 33~62%;shrinkage cavity transformas from conical-shape to basin-shape.The hight of denser part increases, and the riser hight may be decreased by about 25~50%. As a result, the riser metal can be saved up to 20~50%. It can be coucluded that using the exothermic-insulating riser is most efficient and advantageous for the production of spheroidal graphite cast iron rolls.
Abstract: A discrete system simulation mathematical model describing the steel ingot process from teeming to rolling has been developed in this article a-ccording to the source material which was abstracted from on month is recording data and production schedule of a blooming mill. A good many simulation calculations and procedure research have been made with this model on the computer. The simulation results are agreement with the practical data. It is cleavthat this model is satisfactory with the steel ingot process. The mathematical simulation model and its simulation results can supply a decision basis for technicians of production schedule and m-anagement in rolling mill, and also can prouide refrence for system researcher of process control.
Abstract: Ln this work,the fluid flow field in a bath caused by imping gas jet are studied by means of experiment with a physical model together with numerical solution of the mathematic model. Velocity distribution of the fluid flow in the bath is measured by laser Doppler anemometer. The mathematic model consists of the kinematic and dynamic equations of turbulent flow,one equation model of turbulence and newly defined boundary equa tions. The mathematic model is numerically solved implicitly using method Solving recirculating flow problems developed by Prof.Spalding, so that, the flow pattern,the distribation of velocity,vorticity,turbulent kinetic energy, and turbulent viscosity are obtained.The results computed agree well with those measurd in experiments.
Abstract: The amount of four phase in GH220 alloy with high contents of Molyb denum and Tungsten at different heat treatment was determined by guantit-ative X-ray phase analysis. X-ray diffraction method has identified the M6C and μ phase,those are Very difficult to determine by chemical phase analysis. The result of thus research has Provided the basic data fo define the optimum Content of Wand Mo in GH220 alloy.
Abstract: The reversible change and irreversible change in coercivity and mioros-tructure for sintered SmCo5 and Sm(Co, Cu, Fe, Zr)7.0 alloy were studied by magnetic measurement, transmission electron microscopy (TEM) and X-ray diffractions.The causes which lead to these reversible changes have be en discussed.
Abstract: Baysed on the investigation of experimental data in the differential dual drive semi-continuous bar mill φ250mm×6, the following works have been studied: 1,The D. D. D technique may be one effective way in reforming the old rolling mill in our country .2,The load parameters which are needed for reinforcing the machinery design of the differential case have been proposed. 3,The rolling torqus and power mathematical model for steel angles have been proposed. It is denoted that the optimal roll pass design, the mill set-up system and the flow control system should be studied in order to further develop the continuous shape rolling technique.
Abstract: Hysferesis error is one of the most important factors by which the precision of the magnetoelastic effect force transducer is affected. For the s-ake of investigating the origin of the hysferesis error, a 3%Si-Fe cold rol- led single oriented electric sheet sample was used. In the mesurement region of the sample, there was only one crysial. The results showed that bot-h of the magnitude and the type of the hysferesis error of the sample varied with θ,the angle between the[100] of the crystal and the direction of the stress a.There were two kinds of hysteresis error,one of which was positive and the other negative. In this article the authors analysised the processes of the change in magnetic domains distribution of the sample. It seems that the variation of the magnitude and type of hysteresis error of the sample is due to the interactions between domain walls and crystal defects, particularly dislocations.
Abstract: A Ag/AgCl reference electrode with pyrex glass and porcelain diaphr agm for use in LiCl-KCl-NaCl molten salt system at 480°-600℃ is described.In order to ensure a long periodic stability of the reference electrodefor hygroscopic molten salts a pyrex glass or porcelain tube conductive to sodium ions should be used as a diaphragm;besides,the water arid the oxygen in the molten salts should be removed thoroughly and the assembled electrode should be sealed perfectly.The experimental results show that EMF of the reference electrode with pyrex glass diaphragm was stable and reproducible to within 5 mv,as well as temperature and current-reversible cycling over a period of 110 hours.The inflenence of temperature and cdncentrat-on of AgCl to the electrode potential also has been discussed.It is shown that the concentration of AgCl chosen within 2-4 mol% may be better.
Abstract: Using the theory of absolute reacte rate and statistation mechanics for Chemical vapor deposition (CVD) of tantalum has been Constructed model of Chemical reaction.Experement presented, the agreement between measured and Calculabd data is good The fact seems to prove, rate model which using the absolute reacte rate obtained is correct and the rate-limiting step is the surfacl chemical reaction for Chemical Vapor deposition
Abstract: This paper developed a new type hour-glass worm enveloping by a variable P angle of the generating plane, and obtainned all of the equations of the worm. The drive by this worm will improve its profile in appearance sharp-pointed or undercut under the small velocity ratio.This paper was theorized about with the "Methodology of Envelope" devised by Beijing University of Iron and Steel Technology,
Abstract: The solidification process of steel ingots is simulated with an aqueous solution of NH4Cl-H2O system. The temperature distribution in ingots during solidification and the laws governing solidification process is studied with the solidification experiment of NH4Cl-H2O system, The resulfs of the experiment generally conforns to the theoretical calculations. Both the fluid flow pattern in the simularing mould and the formation process of the channels of macro-segregation are observed adopting colouring method. Meanwhile,the conclusion is reached that the utilization of Argon-blowing into the mould may affects the structure of the 2-phare zone and the formation of the Segregation channels.
Abstract: The accuracy of quantitative analysis of thin foils in The energy dispersive x-ray spectrometer, EDAX9100, has been measured with samples of known composition.The results indicate that at 100KV, a relative error of 5-10% Can be achived using The EDAX9100 program when K-K or L-L x-ray Lines of elements with close atomic number are being analyzed. The relative error becomes progressively worse,up to abont 20% to 50% if The difference in atomic number between The two analyzed elements increaces, and the different x-ray lines are analgzed. The absorption of thin film specimens has been studied The results indicate that x-ray absorption within the sample must be Considered when there is a significant difference in The energy of The Characteristic x-raysAt lower voltages a correction must be applied to the K factor in the EDAX9100 program. The EDAX9100 program must be Corrected for using iines from different x-rag shells.Reasonable equations for calculating the lonization cross section and fluorescence yields have been Chosen, and the ratio of coefficients of K, L and M shell lines have been calculated to be qK:bL:bM=0.35:0.35:0.24. The relative error after correcting the program for absorption,voltage,and different x-ray shells, is less than 10% for all x-ray lines analyged.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
