ISSN 0412-1961
CN 21-1139/TG
Started in 1956

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    , Volume 16 Issue 3 Previous Issue    Next Issue
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    SELECTIVE FLOATATION OF BERYL AND ITS SEPARATION FROM SPODUMENITE
    Zhou Weizhi Guangzhou Institute of Non-Ferrous Metals Research; Ministry of Metallurgical Industry
    Acta Metall Sin, 1980, 16 (3): 249-262. 
    Abstract   PDF (977KB) ( 563 )
    The selective floatation of beryl, especially its separation from spodumenite,has been investigated. For floatation of beryl and separation from gangue mineralsin alkaline medium, the reasonable adjustment between the activating factor, Ca~(2+),and the depressing factors, such as CO_3~(2-) etc., was ascertained. Thus, the unfavour-able effects of "unavoidable ions" in slurry and in hard water on floatationwere remarkably eliminated. As a result, it is developed a "flow-sheet of selectivefloatation of beryl and its separation from spodumenite" which is entirely possibleto floate beryl or spodumenite and even their complex ores with various naturalwaters. This seems to be advantageous to no washing for deslime or other specialtreatments, easy supply of reagents, less expansive, as well as simple, adaptableand flexible operation. Commercial tests verified that beryl concentrate assaying9.2-10.8% BeO with recovery of 88-80% has been yielded from ore containing 0.3%BeO, and also that beryl or spodumenite concentrate assaying 8.5% BeO or 6.0%Li_2O with recovery of 69% or 88% respectively from a complex ore containing0.055% BeO and 0.93% Li_2O. The flow-sheet has been carried into industrial millswith great success.
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    A STUDY OF THE EFFICIENCY OF PERCUSSIVE PENETRATION BY WAVE THEORY
    Zhao Tongwu Changsha Institute of Mining and Metallurgy Research
    Acta Metall Sin, 1980, 16 (3): 263-275. 
    Abstract   PDF (840KB) ( 440 )
    Using uni-dimentional stress wave theory, the penetration function of arbitra-rily incident stress has been derived. For any given long rod-hard rock penetrationsystem with single or double cylindrical piston, the coefficient of the penetrationdepth of each step (u_k) is a linear transform of a pulse-shape vector (ψ_k), andcan be expressed by means of matric or recurrent formula as: (u_k)=(α_(kp))(ψ_k) oru_k=u~(k-1)e~(-λ)+ψ_k, therefore, the penetration efficiency isη=4θ(1-e~(-λ))~2 (max u_k)~2where (α_(kp)) is the characteristic square matrix of system: λ and θ are constants. Attempts have been made to compute the penetrating efficiency of the doublecylindrical piston with different cross-section characteristics by a digital computer,with the shake to head length ratio j=4 or 5, which is the normal value forengineering design. The single cylindrical piston may be regarded as a particularcase of the double one. Owing to the fact that all arbitrary specific incident stress pulse can be ap-proached by a step function with a sufficiently short period Δt, this method maybe applicable to the calculation of the efficiency of penetration with arbitrarystress pulse.
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    THREE-DIMENSIONAL ORIENTATION ANALYSIS FOR COLD-ROLLED 08Al STEEL SHEET
    Liang Zhide;Xu Jiazheng;Wang Fu North-Eastern Institute of Technology
    Acta Metall Sin, 1980, 16 (3): 276-282. 
    Abstract   PDF (479KB) ( 600 )
    An ALGOL-60 program is written for the calculation of the ODF for cubicmetals. Using this program the cold-rolled texture of 08Al steel sheet has beendetermined. It is shown that this texture is composed of two branches: the weakerone is concentrated {001}〈110〉, other has a stronger {111} fiber component anda strong {211} 〈011〉. In this program the ODF is expanded in a series of generalized sphericalharmonics truncated at l=16 and is inversed from two pole figures of the sample.The weights α_l~i have been introduced in the calculation of the coefficients W_(Imn) ofthe series for l=4,6,8,10,14. It has been proved that a_l~i is determined by the ?_i,Φ_i and l, and is independent of the orientation distribution of the plane i in thesamples. Furthermore, the numerical values of Z_(lmn)(ξ) are calculated by a simplerecurrence relation. The program, as a whole, is rather simple and time-saving.
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    A STUDY ON THE INITIAL CARBIDES FORMED DURING ISOTHERMAL DECOMPOSITION OF AUSTENITE IN CHROMIUM STEEL
    Liu Qing Shanghai Jiaotong University
    Acta Metall Sin, 1980, 16 (3): 283-289. 
    Abstract   PDF (550KB) ( 618 )
    Carbides formed initially during isothermal decomposition of austenite in sevenchromium steels have been studied by X-ray diffraction method. The relationshipsexisting between Cr/C ratio and types of initial carbides formed have been con-firmed and re-explained by a new concept. It was also found that the carbidesforming process is dependent on the decomposition temperature of austenite. Withdifferent Cr/C ratios and decomposition temperatures, the types of the initialcarbides formed are different. Transition regions possibly exist between any twoadjacent single phase regions in all diagrams.
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    STUDIES ON THE KINETICS OF Ni DISSOLUTION IN AQUEOUS AMMONIACAL SOLUTION
    Xia Guangxiang;Chen Jiayong (Chen Chia-yung) Institute of Chemical Metallurgy; Academia Sinica
    Acta Metall Sin, 1980, 16 (3): 290-301. 
    Abstract   PDF (919KB) ( 450 )
    Studies have been carried out on the kinetics of Ni dissolution in aqueoussolution of NH_3 and (NH_4)_2CO_3 with O_2 present. It is shown that the NH_3 andNH_4~+ salt dissolution of Ni is an electrochemical reaction accompanied by surfaceoxidation of Ni by O_2. The reaction rate may be either in the NH_3 concentrationcontrol region or in the O_2 concentration control region depending on the ratio ofthe concentration of NH_3 and that of O_2. In the NH_3 controlling region, the surface of Ni will be passivated rathereasily with the formation of oxide film. The dissolution reaction will then beinterrupted. In the O_2 controlling region, the rate of reaction will be controlled bythe rate of O_2 transfer through the liquid film around the Ni surface. It can becorrelated with the equation of the rate of O_2 mass transfer.
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    AN INVESTIGATION ON THE THERMAL STABILITY OF Ti-679 ALLOY
    Zhou Yigang North-West Engineering Institute
    Acta Metall Sin, 1980, 16 (3): 302-372. 
    Abstract   PDF (1927KB) ( 623 )
    The effect of specimen shape, degree of deformation by forging, surface contam-ination of O_2, chemical composition and microstructure on the brittle fracture ofTi-679 alloy subjected to creep test at 450℃ for 100h have been studied. Thethermal stability of the alloy close to α-region was not only related to the alloycomposition, but also to the microstructure formed in the process of deformation.The appearance of the rolled β structure was regarded as the main cause in dete-riorating the thermal stability of this alloy.
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    AN INVESTIGATION ON THE VAPOUR PHASE EPITAXY OF DOPED GaAs
    Peng Ruiwu;Sun Shangzhu;Shen Songhua Shanghai Institute of Metallurgy; Academia Sinica
    Acta Metall Sin, 1980, 16 (3): 308-373. 
    Abstract   PDF (1399KB) ( 672 )
    Epitaxial layers of doped GaAs have been prepared from a Ga/AsCl_3/H_2 systemin an improved epitaxial apparatus and the vapour-phase doping process of the GaAshas been investigated. The quality of these layers thus obtained was found to besatisfactory and they are used in making microwave devices such as variators andswitches. Discussions on a variety of factors including surface morphology, growthrate, electronic mobility, breakdown voltage, doping uniformity across a wafer,doping profile, defects and reproducibility of the epitaxy were made.
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    THE ENVELOPING METHOD OF DETERMINING CROSS ROLLER SHAPE——A Discussion on "A Mathematical Treatment on Cross Roller Design"
    Ma Xiangfeng Beijing Institute of Iron and Steel Technology
    Acta Metall Sin, 1980, 16 (3): 318-324. 
    Abstract   PDF (519KB) ( 717 )
    According to practices, a general equation for the determination of the crossroller shape has been derived on the basis of the mutual relation between movingstocks and rollers which is further considered as the relation between generatingand enveloping surfaces. It appears that this is applicable to the designing calcula-tion of cross roller shapes with either helical or revolving surfaces.
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    AN INVESTIGATION OF THE CARBON MIGRATION PROCESS IN THE WELDED JOINT OF A 12AlMoV STEEL
    Ni Ruicheng;Li Chengxiu Shonghai Institute of Materials Research)and Shanghai № 3 Steel Works
    Acta Metall Sin, 1980, 16 (3): 325-374. 
    Abstract   PDF (1200KB) ( 652 )
    An investigation of the first kind migration process of carbon has been carriedout on the welded joints of a 12AlMoV steel by means of microscopy, EPMA anddilatometry. It is shown that this carbon migration is caused by the existance ofa significant activity gradient of carbon between the two sides of fusion line. Thismay take place as a result of the earlier precipitation of pro-eutectoid ferrite onone side of the fusion line within a temperature range that rapid diffusion ofcarbon atoms occurs. This confirms the activity reasoning proposed by the authorfor carbon migration. The difference of the activity coefficient of carbon caused by different crystalstructures is larger than that caused by different compositions of the alloys forthese welded joints. Hence, it is the main thermodynamic condition accountingfor this kind of carbon migration. From kinetic point of view, the degree ofcarbon migration increases with the duration under certain temperatures. Changingthe composition as well as modification of welding technology have been proposedso as to retard or suppress the carbon migration in the welded joints of the steel.
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    SOME FACTORS AFFECTING THE WELDED JOINT FRACTURE IN HOT-ROLLED SILICON STEEL COIL
    Qi Lian;Pu Shaokang;Yin Biqun Research Institute of Wuhan Iron and Steel Company
    Acta Metall Sin, 1980, 16 (3): 331-377. 
    Abstract   PDF (2054KB) ( 505 )
    An investigation of the relationships between cold bending plasticity and micro-structures of welded joints in hot-rolled silicon steel coil in welded and heat-treatedconditions has been carried out by optical microscopy, TEM, SEM, and stressanalysis. It is shown that the martensite and carbide formed in weld junctionsand overheated zones as well as the coarse grains in the overheated zones are themain factors responsible for the welded joint fracture. The intersection of numerousdeforming twins in the overheated zones during deformation and their impactagainst phase boundaries also leads to an initiation of cracks. thus promoting thebrittle fracture of the welded joints.
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    AN ETCH METHOD OF REVEALING CARBIDES IN W CONTAINING ALLOY CAST IRON
    Jiang Xiaoxia Institute of Metal Research; Academia Sinica
    Acta Metall Sin, 1980, 16 (3): 336-378. 
    Abstract   PDF (1292KB) ( 521 )
    The electrochemical behaviour of the carbides in W containing alloy cast ironhas been investigated in the basic solution. As a result, the potentiostatic electro-lytic and chemical etch method for differentially revealing various carbids in thisalloy is proposed.
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    CALCULATION OF THE α CORRECTION FACTORS FOR ELECTRON MICROPROBE ANALYSIS OF OXIDES AND ITS APPLICABILITY
    Guan Ruonan Institute of Metal Research; Academia Sinica
    Acta Metall Sin, 1980, 16 (3): 341-348. 
    Abstract   PDF (679KB) ( 530 )
    The correction factors for electron microprobe analysis of 14 oxides at anaccelerating potential of 20kV and a take-off angle of 18° have been calculatedusing a computer program written in FORTRAN language. The C/K vs C curve wasshown to be non-linear. The errors caused by the supposition of a linear C/K vsC relationship and the use of these α correction factors have been discussed.
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    EFFECTS OF Pb AND Mg ON THE PROPERTIES OF LONG TERM AGING Zn-4Al ALLOY
    Wang Zuochen Changchun Institute of Optical and Fine Machines; Academia Sinica
    Acta Metall Sin, 1980, 16 (3): 349-379. 
    Abstract   PDF (1709KB) ( 751 )
    Tests were made of the effects of Pb and Mg on the property changes ofZn-4Al alloy in 20 years natural aging. It appears to that Pb is favourable tothe phase transformation of alloy which is remarkably caused its volume change.Mg dissloves in the Zn alloy with in its certain maximum solubility only. Thisseems to be independent of Pb contaminated. The optimum addition of Mg maythen be chosen properly. Furthermore, the influence of presence of Cu was alsodiscussed.
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    MICROSCOPIC IDENTIFICATION OF AIN
    Zhang Detang
    Acta Metall Sin, 1980, 16 (3): 354-382. 
    Abstract   PDF (2821KB) ( 432 )
    A microscopic observation on AIN phase is made together with EPMA, X-rayor electron diffraction analysis. Its crystalline structure as well as chemical andmechanical properties are presented, and its original colour or optical feature isshown in colour photos.
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    ON THE WETTABILITY OF CARBON ELECTRODES BY MOLTEN CRYOLITE-ALUMINA ELECTROLYTE
    Qiu Zhuxian and Wei Chingbin
    Acta Metall Sin, 1980, 16 (3): 357-361. 
    Abstract   PDF (1411KB) ( 494 )
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    ELECTROMIGRATION PHENOMENON IN TUNGSTEN
    Wu Yunzhong Shanghai Institute of Metallurgy; Academia Sinica
    Acta Metall Sin, 1980, 16 (3): 362-383. 
    Abstract   PDF (1287KB) ( 487 )
    Hairpin tungsten filaments showed premature failure in conducting directcurrent. The cause of this failure was interpreted as the superposition of theelectromigration and the Soret effect. An effective method has been proposed toimprove the life-time of the filament.
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    EFFECTS OF CONCENTRATION AND AVERAGE VALENCE OF TITANIUM SUBCHLORIDES ON THE ELECTRO-CRYSTALLIZATION OF TITANIUM
    Yang Qiqin;Liu Guankun;Fang Beilong Zhongshan University
    Acta Metall Sin, 1980, 16 (3): 365-384. 
    Abstract   PDF (1159KB) ( 660 )
    The effects of concentration and average valence of titanium subchlorides onthe electrocrystallization of titanium in a NaCl-KCl melt have been investigated.When the Ti ion concentration was about 2% and the average valence was nothigher than 2.4, the crystals obtained were coarse. A possible explanation of thisphenomenon is as follows: In NaCl-KCl melts, complex ions of Ti will form, andchemically, the Ti~(2+) complex ions are less stable as compared to the Ti~(3+) complexions. This will lead to comparatively small overpotential in electrodeposition. There-fore, lower average valence is conductive to the formation of rather coarsercrystals. With a view to improving the current efficiency and the quality of Tiin the electrolysis of TiCl_4 by basket cathode, measures which can raise theconcentration of titanium subchlorides as well as lower the average valence, suchas adding Ti to the gas-melt interface in the basket should be adopted.
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    GLIDE DEFORMATION OF METALLIC GLASSES UNDER CONCENTRATE LOADING
    Patu;Su Huihe Institute of Metal Research; Academia Sinica
    Acta Metall Sin, 1980, 16 (3): 368-386. 
    Abstract   PDF (2212KB) ( 477 )
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