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

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    , Volume 16 Issue 2 Previous Issue    Next Issue
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    SPATIAL ORIENTATION DISTRIBUTION OF CRYSTALLITES IN COLD-ROLLED AND IN ANNEALED SHEETS OF DEEP-DRAWING PHOSPHORUS STEEL
    Hsun Hu U. S. Steel Research Laboratory
    Acta Metall Sin, 1980, 16 (2): 121-139. 
    Abstract   PDF (1551KB) ( 534 )
    The cold-rolling and annealing textures of a deep-drawing phosphorus steelhave been studied by he patial orientation distribution of the crystallites. Thecharacteristics of the orientation distribution unctions of the as-cold-rolled andof the annealed sheets were closely examined. The observed features uggest thatthe annealing texture is originated by microband or transition-band nucleation,followed by the rowth of recrystallized grains at the expense of the matrix de-formation textures. The crystallite rientation distribution of the annealed sheetof the deep-drawing phosphorus steel is clearly different from hat of the annealedsheet of deep-drawing aluminum-killed steels.
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    OBSERVATION OF THE FATIGUE FRACTURE SURFACE OF HIGH STRENGTH STEELS
    Sun Fuyu;Liao Chienchu;Lan Fenlan;Liu Caimu;Liu Jianhua Central Iron and Steel Research Institute; Ministry of Metallurgical Industry
    Acta Metall Sin, 1980, 16 (2): 140-251. 
    Abstract   PDF (3467KB) ( 751 )
    The fatigue fracture surfaces in specimens of two high strength steels havebeen examined by SEM nd discussed in terms of the propagation rate curve(log da/dN vs logΔK) of fatigue cracking. The results btained are as follows: (1) Fracture surfaces corresponding to the lower growth-rate exhibit three dis-tinctive zones of different appearance, showing that the propagation of cracks inthis region consists f hree stages, i.e. crack initiation, crack propagation, and atransition stage which dominated by both ransgranular striation growth and in-tergranular fracturing mechanisms. (2) In the intermediate growth-rate egion the propagation of fatigue cracksprincipally takes place by a striation mechanism, though the triation space (S) doesnot coincide with the macrocrack propagation rate (da/dN). (3) In the high rowth-rate region the rate propagation of fatigue cracks isgoverned by the striation growth mechanism as ell as by the dimple mechanism.The interaction between these two mechanisms and the pattern of the growth fdimples have been investigated quantitatively.
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    THE FORMATION OF Ni_5Hf AND THE SECONDARY CARBIDE IN HAFNIUM-BEARING CAST SUPERALLOYS
    Zheng Yunrong;Cai Yulin
    Acta Metall Sin, 1980, 16 (2): 151-253. 
    Abstract   PDF (3104KB) ( 853 )
    The Ni_5Hf phase in hafnium-bearing nickle-base cast superalloys has beenexamined. It was found hat the reactions occurring in this series of alloys mightbe described as follows:Ni_5Hf+γ(C)-MC)_(2)+γor '(Hf)+γ(C)-MC_(2)+γThe effects of these reactions on the stability of the alloys have been discussed.
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    A TITANIUM CARBOSULPHIDE PHASE IN ALLOY STEELS AND SUPERALLOYS
    Zhang Jushui;Chen Jiaguang Research Institute of Daye Steel Works
    Acta Metall Sin, 1980, 16 (2): 159-256. 
    Abstract   PDF (2928KB) ( 807 )
    The morphology, optical characteristics and composition of a titanium carbo-sulphide phase ccurred in certain low-alloy steels, stainless steels and superalloyshave been investigated by optical icroscopy, TEM and EPMA. Its crystallinestructure has been identified by selected-area electron diffraction echnique. Depend-ing on the mechanism of formation, this phase exhibits two different growthhabits: latelets formed directly from the molten alloy are distributed at cast grainboundries, while very thin aminae were precipitated at austenitic grain bound-aries during cooling from a high temperature. It appears hat the amount of thisbrittle phase in the alloys can be greatly diminished by the addition of smallamounts f rare-earth elements. The composition of this phase is found as:(Ti_(1-m)X_m)_2S(C_(1-n)N_n)
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    A STUDY OF THE STRESS CORROSION CRACKING OF SENSITIZED 1Cr18Ni9Ti STAINLESS STEEL IN HIGH TEMPERATURE HIGH PRESSURE WATER
    Chen Junming;Chou Fugen;Yu Fanghua Shanghai Institute of Metallurgy; Academia Sinica Shanghai Institute of Nuclear Research; Academia Sinica
    Acta Metall Sin, 1980, 16 (2): 165-257. 
    Abstract   PDF (2189KB) ( 624 )
    The corrosion behaviour of sensitized 1Cr18Ni9Ti stainless steel in high tem-perature water was nvestigated from the environment angle. Stress corrosion crack-ing would occur in an acidic or neutral high emperature water in the presenceof a definite concentration of Cl~- and/or O_2. SEM electron fractographic nalysisshowed that in Cl~- containing water cracking was intercrystalline, while in O_2bearing water, racking was of a mixed type, mainly as cleavage. The apparentand real corrosion kinetic curves of Cr18Ni9Ti n high temperature water weregiven. It was shown that corrosion consisted of both dissolution and wet xida-tion, chiefly the latter. The correlation between the structure of the oxide films andcorrosion has een studied by means of Mossbauer internal conversion electronspectroscopy. In the case of general orrosion, the film consisted predominantlyof Fe_3O_4, while in the case of stress corrosion, the film onsisted of a multi-layerstructure with Fe_2O_3 as a predominating layer overlapped with layers containingFe_2O_3 and Fe_3O_4. In a boron containing water, FeBO_3 phase might appear in theoxide film ocally, but it neither caused nor inhibited stress corrosion. This "inert"behaviour of boron is related to he non-stoichiometry of Fe_3O_4 in the film tomake it anion-selective in nature. Based on corrosion-electro hemistry, it may beconcluded that stress corrosion takes place between the passive and transpassive regions n the polarization curve. Increasing Cl~- or O_2 content shifts the potentialof the alloy toward the ranspassive region. The action of Cl~- and O_2 are tochange the anodic and cathodic polarization curve espectively. It was suggestedthat in the Cl~- containing water the rapid dissolution of TiC along boundary sthe main cause of stress corrosion, while in the O_2 bearing water, the selectivedissolution of Cr in the lloy is critical. After thoroughly reviewing the charac-teristics of stress corrosion, the authors were nclined to think that stress not onlyis one of the causes for the serious corrosion pits, but also induced ctive pathswhich accomodate, accelerate and help guide the metallic atoms in the pit in dis-solving egularly. Finally, a preliminary model of stress corrosion cracking of1Cr18Ni9Ti in high temperature high ressure water has been proposed.
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    STRESS CORROSION OF HIGH STRENGTH STEELS IN WATER MEDIUM
    Chu Wuyang;Li Shiqiong;Xiao Jimei (Hsiao Chi-mei);Wang Cheng Beijing Institute of Iron and Steel Technology
    Acta Metall Sin, 1980, 16 (2): 179-259. 
    Abstract   PDF (2031KB) ( 832 )
    A review was made of the modified WOL-type constant displacement speci-men for stress corrosion by which the _(Iscc) and da/dt of four high strength steels,as 30CrMnSiNi_2A, 40CrNiMoA, 30CrMnSiA and ZG-18 cast steel, in water me-dium were evaluated. Among these steels, the influence of heat treatment, thestrength and microstructure of 0CrMnSiNi_2 A on the K_(Iscc) and da/dt has beenstudied in detail. The K_(Iscc) obtained may be increased with decrease f heir ownstrength of specimens undergone same heat treatment. while the K_(Iscc) of specimens,which were isothermal uenched and tempered for structure of equal strength,may be much higher than specimens with both martensite and on-temperedbainite structures. The growth and extension of cracks may be changed whenthe tensile strength of steels σb=130-140 kgf/mm~2, in consequence, the K_(Iscc)increases markedly and da/dt decreases to greater extent. The threshold alues of stress corrosion cracking K_(Iscc)(ρ) was measured bymodified WOL-type notched specimens of various tip radius as follow:K_(Iscc)(ρ)={B ρ≤ρ_0 Aρ~(1/2) ρ>ρ_0where A and B are material constants. For ultra-high strength steel 0CrMnSiNi_2A, A=4170MPa, B=22MPa·m~(1/2) and ρ_0=1.027mm. This correlation conformsto theoretical treatment. According o the experimental results, the accidental failures of the fasteningscrew made of ultra-high strength steel 30CrMnSiNi_2 ere quantitatively ana-lyzed by linear elastic fracture mechanics. Therefore, the remedy to prevent thefailure of astening screw has been suggested.
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    ACTIVITY OF La_2O_3 IN LIQUID La_2O_3-CaF_2 AND La_2O_3-CaF_2-CaO-SiO_2 SLAGS
    Wang Changzhen;Zou Yuanxi (Chou Yuan-hsi) North-Eastern Polytechnical Institute Shanghai Institute of Metallurgy; Academia Sinica
    Acta Metall Sin, 1980, 16 (2): 190-194. 
    Abstract   PDF (369KB) ( 523 )
    The activity of La_2O_3 in liquid La_2O_3-CaF_2 and La_2O_3-CaF_2-CaO-SiO_2 slagshas been determined at 1500℃ y equilibrating the slags with liquid tin in agraphite crucible under one atmosphere of carbon monoxide. From the ctivitydata on the La_2O_3-CaF_2 system, the activity of CaF_2 has been obtained by Gibbs-Duhem integration. The activity ata on the above mentioned slags are briefly discussed on thebasis of ionic constitution of liquid slags.
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    THE LINEAR CONCENTRATION RULES AT CONSTANT PARTIAL MOLAR QUANTITY ■_O——THE EXTENSION OF THE TURKDOGAN'S AND THE ZDANOVSKII'S RULES
    Wang Zhichang Shanghai Institute of Nuclear Research; Academic Sinica
    Acta Metall Sin, 1980, 16 (2): 195-206. 
    Abstract   PDF (755KB) ( 507 )
    The Turkdogan's rule is a linear concentration rule of the solubility ofcarbon in the molten Fe-alloys, while he Zdanovskii's rule is that of the mixed elec-trolytes at isopiestic condition. Both are linear concentration rules at onstantchemical potential μ_0. In this paper, these two rules are expressed by three different concentration units(mole raction, molality and weight percent) and are extended to the general linearconcentration rules at constant partial molar uantity Ψ_0 applicable to all thermo-dynamic properties Ψ of any n-component (n≥3) solutions. It is pointed out thatthe Zdanovskii-type's rule is a special example of the Turkdogan's rule extendedto whole region of concentration at onstant Ψ_0. The above conclusions are verified by examining published data dealing withsuch properties as Gibbs free nergy, enthalpy, heat capacity or volume for solu-tions of liquid and solid alloys, molten salts, electrolytes or olymers.
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    A DATA HANDLING AND CORRECTING PROGRAM FOR QUANTITATIVE ELECTRON MICROPROBE ANALYSIS
    Wang Wenhao;Guan Ruonan Institute of Metal Research; Academia Sinica
    Acta Metall Sin, 1980, 16 (2): 207-217. 
    Abstract   PDF (879KB) ( 682 )
    A data handling and correcting program adaptable to a minicomputer(16k mem-ory) for use in quantitative lectron icroprobe analysis was written in FOR-TRAN. The program is applicable to all elements in the atomic number range from5(B) o 92(U) and has the capability to deal with 12 elements and 30 measuringpoints each time. The data handling sub-program llows the time and number ofmeasurements for each analysing point to be varied at will and gives the averageintensity atios K as the output. The correcting sub-program allows the correctionof atomic number, absorption and fluorescence ffects and can handle various el-ements at different accelerating voltages. All physical constants, except atomicweights hich are stored in the memory, are calculated in the program, so thatonly few input data are needed.
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    LOW-FREQUENCY "AMPLITUDE PEAKS" IN THE INTERNAL FRICTION ASSOCIATED WITH THE INTERACTION OF SUBSTITUTIONAL SOLUTE ATOMS WITH DISLOCA-TIONS IN ALUMINIUM ALLOYS
    Ge Tingsui (T. S. Kê) Institute of Metal Research; Academia Sinica
    Acta Metall Sin, 1980, 16 (2): 218-230. 
    Abstract   PDF (867KB) ( 462 )
    Low-frequency "amplitude peaks" and "temperature peaks" were observed inthe internal friction of dilute Al-Cu nd Al-Mg alloys around room temperature ata maximum surface-strain amplitude ranging from 5×10~(-7) to 1×10~(-5). This nom-alous internal friction showed a peculiar aging behaviour. An aging peak wasobserved in conjunction with the mplitude eak and the temperature peak. Suchpeaks have been observed repeatedly in: (1) heavily cold-worked specimens an-nealed ust rior to complete recrystallization; (2) fully annealed specimens cold-worked just after yielding; (3) fully annealed pecimens quenched from anelevated temperature. It is shown that the observed internal friction is associated with the nterac-tion of solute atoms (Cu and Mg in Al) with the mobile "fresh" dislocations pro-duced by cold-work or quenching. uch fresh dislocations contain a large numberof kinks. A modified dislocation atmosphere model was suggested in which thesolute atoms are assumed to be dragged along between two potential valleys dur-ing the to and fro sidewise motion of a ink under the action of the appliedalternating stress.
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    SOME ASPECTS IN THE TECHNICAL DEVELOPMENTS OF LD REFRACTORIES IN CHINA
    Zhong Xiangchong (Chung Heung-sung) Luoyang Institute of Refractory Research
    Acta Metall Sin, 1980, 16 (2): 231-261. 
    Abstract   PDF (2644KB) ( 714 )
    During the past two and a half years, lining lives of LD converters in Chinahave markedly increased with everal ampaigns exceeding 2000 heats. The averageLD lining life of the Capital Iron and Steel Company has surpassed 1000 heats.Improving the quality of refractory materials used has played a decisive role inthis increase. It has been proved hat natural dolomite and magnesitic dolomite are suitableraw materials for LD lining; the technical properties of bricks ade from them arequite satisfactory and high lining life can be achieved. A two-stage calcination process has been dopted or the preparation of highpurity dolomite (or magnesitic dolomite) clinker, by which the sintering tempera-ture can be owered 100--200℃. The clinker thus produced possesses uniform com-position and structure as well as improved ydration-resistant and slag-resistant pro-perties. Tar-impregnated burnt brick and tar-impregnated tempered block based n ighpurity clinkers have been developed for zoned lining and considerable increase inLD lining life has been attained. ased on the study of the wear mechanism of LD refractories by slags, it ispostulated that the process consists of ecarburization followed by chemical cor-rosion, which proceeds in two stages-attack by the initial acidic slag and then t-tack by the high ferrous slag at high temperatures. Slag resistance tests have shownthat synthesized magnesitic lomite xhibits superior resistance to both acidic andferrous-bearing slags.
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    THERMOGRAVIMETRIC STUDY OF DIRECT CARBURIZING BY NATURAL GAS
    Tan Zhicheng;Zhou Lixing;Tan Huiling;Mei Wenlin Dalian Institute of Chemical Physics; Academia Sinica Dept. of Metallurgy; Chongqing University
    Acta Metall Sin, 1980, 16 (2): 239-244. 
    Abstract   PDF (358KB) ( 627 )
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    AN ELECTRON DIFFRACTION STUDY OF γ" PHASE IN Ni-Fe-Cr-Nb ALLOY
    Li Yuqing;Liu Jingyan Research Institute of Daye steel Works
    Acta Metall Sin, 1980, 16 (2): 245-262. 
    Abstract   PDF (880KB) ( 521 )
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