Abstract: Flotation Process on silica sand wtfhout using fluoride was studied and summarized in this paper.Some, practicable flowsheets were suggested.It Was stressed that fresh surface of minerals, reasonable value of pH and suitable time of conditioning pulp were all very important. It was considered that using some amine salt (e.g. R-o-(CH2)3-NH2) as collector either alone or mixed with sodium petroleum sulfonate would result in obviously separating feldspar from guartz. The reason for it might be related to the characters of cationic activation group of the collector.
Abstract: The selection of cut-off draw-grade is closely related to the resource reco-vory, profit and annual output of concentrate, thus it is concerned with the-composite, technical-economic effect. This paper is only to discuss emphatically one of them, that is the profit index. This paper suggests three knids of profit index to evaluate the economic effect, they are:1) the profit per ton of the write off recoverable reserve; 2) the profit per ton of recovered orc; 3) profit-cost ratio. The relationship between marginal benefit and mean profit is analyzed from the point of view of marginal benefit, so that the criteria of maximum value of the above mentioned profit indexes can be deduced respectively. To use these criteria and the two break-oven points, the draw process can be divided into severed section and each of them has diffeient benefit leved, which provide economical bisis for final dcsision of cut-off draw-grade.
Abstract: For the sake of further realizing the characteristic of the EOF slag of Pan-Zhi-Hua Steel Works we have drawn and tested the CaO-SiO2-V2O5, FeO-SiO2-V2O5 and CaO-FeO-V2O5 ternary phase diagrams which are based upon six binary phase diagrams, and using these diagrams to explain some specific properties of the vanadium bearing slag. The behaviour of the vanadium bearing slag in smelting process has been discussed. The influence of some common oxides on the property of slag as well as on the saturation of MgO in slag have also been calculated and illustrated.
Abstract: The speed of the decay of the jet stream discharged from the five-orifice lance nozzle has been measared. The result shows that the speed of the decay of the central and the peripheral jet's velocity isn't identical which is caused by the difference of the jet's surrounding condition. When the diameter of the central orifice(C.O)is equal to the diamefer of the peripheral orifice(P.O), the velocity of the central jet is twice as fast as the velocity of the peripheral jet, in the condition of the common lance height. In order to make fuller use of these jets to agitate effectively and homogeneously the molten bath, the velocity of the central jet should be equal to, or slightly greater than, that of the peripheral one at the surface of the molfen bath. In order that this object can be obtained, the design of the five-orifice nozzle ought to make the area of C. O(Ac) less than that of each P. 0(Ap). According to the measured result, Ac/Ap should be equal to 0.6~0.8.
Abstract: The effects of ce on the solidification and the dendritic segregation of 35CrNi3MoV and 20CrMoV steels have.been studied by means of thermal ana, lysis, metallographic examination and electron microprobe. The results indicate that addition of cerium into steel decreases the undercooling of liguid-solid transformation of the steel,delays the peritectic reaction, refines primary grains of steel, refines secondary dendrite arm spacings of equ-iaxed crystals and decreases the dendritic segregation of Cr, Mo, V, Mn,Si,Ni etc, in different degrees.
Abstract: Stable austenite cell structure in high manganese casting steel was obtained by strictly controlled directional solidification technique. The experimental results have shown that when cerium content increases the cell structure changes into dendrites and then into separated crystals.The influence of cerium on manganese segregation in cells, in columnar crystals and dendrites was studied by ele-ctronprobe analysis. on the basis of some previous work of other authors and with the consideration of solute diffusion in solid state, a formula which describes manganese distribution in high manganese steel was derived. By analysis of the experimental data, it has been shown that the solute equilibrium partition coefficient Ko is the determinative factor which influences dendritic segregation.
Abstract: Heating process of ingots has been simulated by a computer, and a developed mathematical model has been solved numerically. In this way, it is possible to calculate different parameters nelated fo various charging conditions and heating operations, such as the relationship between temperatures and fuel consumptions and heating time, the most suitable length of time at different, periods of heating. It is also possible to calculate fuel consumptions, productivities of soaking pits and so on. The calculation can be used to study heating regulations of soaking pits,and estabish a mathematical model for control of soaking pits with computers.
Abstract: The continuous cooling transformation diagrams and hardenability of 40. 40Si2,40Mn2 and 40Si2Mn2 steels have been determined by the end-quenching method.At the same time,the influence of Si or Mn on the hardenability of Si-Mn-Mo-V steels has been investigated and the multiple hardenability factors for half-martensite content in the center of the ideal critical diameters were also calculated.These results semi-quantitatively shows the relationship between hardenability and the Si and Mn contents in the steels. These experiment results also show that Si raises the temperatures of pro-eutectoid ferrite transformation and pearlite transformation to higher temperatures and also moves the transformation diagram slightly to the right. When Mn or Mo, especially Mn, was added to the carbon steel, the temperature of bainitic transformation is lowered and time of transformation markedly increased.The influence of Si and Mn on the transformation114 diagrams and hardenability is much more pro Bounced when they are added together than added singly.In this case,the transformation diagram will be moved towards the lower-right direction.The effectiveness of alloying elements on increasing hardenability decreases according to the order of Mn Mo and Si.However the hardenability of 40Mn steel can be hardenability of greatly increased by Si addition.The combined effect of Si and Mn on the steel is not on additive basis,but on multiple One.So that in order to keep 40SiMnMoV steel having sufficient hardenability,more than 1.5%Mn,1.3% Si and proper amount of Mo must be added.
Abstract: WC-Fe/Co/Ni hard metal Can be produced With Conventional process of hard metals. Experiments Show that Fe/Co/Ni alloy in an effective binder alloy for hard metals. Cost of hard metal Can be reduced by using Fe/Co/Ni binder. The Paper also discussed the effects of Composition. Content and Struture of binder Phase on the Properties of hard metal.
Abstract: A Can Plastometer Was used to Compress Cylindrical specimens. There are hollows on the cross-section of one end of the specimens and the hollows were filled up with glass powder with various fusion temperatures. A heat keeping device was used to assure uniform and constant temperature during the experiment. The experimental results concern with the resistance to deformation of ten types of steel at elevated temperature and high strain rates. The experimental conditions were as follows:temperature 850-1200℃, Strain rate 5-80S-1 and reduction up to ln2(e=ln1hH). In this paper the experimental method has been described and influences of temperature of strain rates and of reduction on the resistance to deformation hsave been analysed. By linear and non-linear regression analysis of the exper mental data, a formula for calculating resistance to deformation which may be preferable for either computer-controll model or engeneering practice was recommended. The formula is: $\sigma ={\rm{EXP(}}\frac{{{{\rm{U}}_1}}}{{\rm{T}}}{\rm{ + }}{{\rm{U}}_2}{\rm{)\cdot(}}\frac{{\rm{u}}}{{10}}{{\rm{)}}^{{{\rm{U}}_3}{\rm{T + }}{{\rm{U}}_4}}}{\rm{\cdot}}\left({{{\rm{U}}_6}{{(\frac{{\rm{e}}}{{0.4}})}^{{{\rm{U}}_5}}}-({{\rm{U}}_6}-1)\frac{{\rm{e}}}{{0.4}}} \right)$ here:T=$\frac{{{\rm{t}} + 273}}{{1000}}$ U1-U6 are coefficients determined by the properties of the experimental steel.
Abstract: The morphologg of ferrite of deep drawing scel 20A after different treatment has been studied by optical microscope and electron microscope. It was found that the morphology of ferrite is related to the cooling mode and the cooling rate.The morphology is in reasonable agreement with Dubes Classification. The mechanism of the nucleation and growth of ferrite was discussed.
Abstract: The embrittlement tendency of deep drawing shell steel 15A which hao two different morphologies of ferrite (W-ferrite and mass ferrite) has been studied by means of two methods, i.e,impact test with sharp notch at room temperture and high speed tensile test with notch at -80℃. The resulfs showed that the specimens with mass ferrite were more brittle than those with W-ferrite when the grain size of the prior Austenite is the same,These results haoe been further discussed.
Abstract: The process of boron segregation to austenite grain boundary has been inv-erstigated by particle-tracking autoradiography of Jominy bar of a medium carbon boron steel (0.54%C, 0.75%Mn and 0.0027% acid soluble boron) quenched from different temperatures (800-1150℃) after heating to a same high austen-itizing temperature (1150℃). It has been shown that the boron segregation to austenite grain boundary in quenched specimens increases with increasing quenching temperature and is related to and dominated by a process other than equilibrium adsorption. In the present work, it has been found that at any position of the Jominy bar, the grain boundary segregation develops continuously during cooling and the final extent of segregation varies with Jominy distance. The grain boundary segregation intensifies as the cooling rate decreases and changes from continuous boron-enriched networks to discontinuous aggregation and even to discrete precipitation of boron constitutents. The developing rate of grain boundary segregation increases with increasing quenching temperature. The boron concentration profiles and the widths of boron-depleted zone have been experimentally measured, and the developing rate of grain boundary segregation estimated and related to the hardenability of boron steel. Under a given quenching temperature, the width of the boron-depleted zone X is inversely proportional to $\sqrt {\rm{A}} $, where Ai is the cooling rate or X=H(Ti)/$\sqrt {\rm{A}} $.H (Ti) increase with increasing quenching temperature and is a reflection of the rate of grain boundary segregation and effects of composition and other structural factors. It is suggested that the effect of boron on the ha-rdenability depends on the relative rate of segregation to austenite grain boundary and the incubation of the austenite decomposition, and is at its best when the correlation of both rates is optimum.
Abstract: An apparatus was designed to measure the temperature of the grnding spot in a grinding process. The dimension of the target area is about 0.4 × 0.6mm8 Its measuring temperature range is from 600℃ to 1700℃.Thus,this apparatus can be used for many other purposes. The principle and structure of this infrared thermometer were briefly stated. The situations of it's application in the grinding experiments were also mentioned.
Abstract: The deposition temperature can be hold below 570℃ by using pure ammonia durnig CVD of TiN on the surface of iron and steel parts. After deposition quenching is not necessery for the tools nmade of high speed steel. The preparation of pure ammonia used for deposition and the optinum condition for deposition at lower temperature were investigaled. The deposition rate is 2.5/μm/hr, the hardness of the layer of deposition is about 1700kg/mm2, X-Rays diffraction indicates that the product of deposition on the surface is TiN.
Abstract: In this paper, according to the rigid-plastic finite element method we have analized the three dimenssional flow of metal in the rolling by 20 nodals curved hexahedron isoparametric element.The three dimenssional flow velocity fi-eed of metal in the rolling and the deformed Shape of workpiece in steady-state flow have been obtained. The results got from computation have compared with the experiments.
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
