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

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    INVESTIGATION OF AN Fe-Mn-Al-Cr AUSTENITIC HEAT-RESISTING STEEL 37Mn31A13Cr2MoVWNbB
    ZHANG Yansheng; ZHANG Futian (Institute of Metal Research; Academia Sinica; Shenyang); GAO Hueiyou (Fushun Steel Works; Liaoning); WANG Genyuan (Hudong Ship Building Yard; Shanghai) (Manuscript received 10 March; 1983; revised manuscript 20 July; 1983)
    Acta Metall Sin, 1984, 20 (1): 1-8. 
    Abstract   PDF (1083KB) ( 587 )
    An attempt was made to develop a new austenitic heat-resisting steel of FeMn-Al-Cr system. An experimental steel 37Mn31A13Cr2MoVWNbB has been investigated. It was resulted that the alloy phases such as V_4C_3, NbC and M_3B_2 are found in the steel after treatment under 1150℃ 1h, W.Q.+790℃ 20h, A. C. Among them, the V_4C_3 contributes markedly to the strength of the steel toward such extent that its high temperature strength approached that of A-286. Its resistance to oxidation is obviously improved due to a less addition of Cr combined with Al. Cr can also promote the precipitation of X-phase if the steel aged for a long period up to 500h at 650℃ besides the Laves-phase. Some blades made of this steel were equipped on a turbosupercharger which has been successfully operated in a seagoing vessel for several thousands hours. It may be predicted that the developing austenitie heat-resisting steel of Fe-Mn-Al-Cr system seems to be quite a hopeful onefar certain industrial applications.
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    PRECIPITATION OF NbC IN FERRITE AND ITS EFFECT ON PRECIPITATION-STRENGTHENING OF MICROALLOY STEELS
    YONG Qilong; ZHENG Lu (Central Iron and Steer Research Institute; Ministry of MetaZlurgical Industry; Beijing) (Manuscript received 20 September; 1982; revised manuscript 4 June; 1983)
    Acta Metall Sin, 1984, 20 (1): 9-16. 
    Abstract   PDF (1406KB) ( 708 )
    The precipitation of NbC in ferrite and its effect on the precipitation-strengthening of the microalloy steels containing 3 different percentages of Nb, i.e. 0.24, 0.15 and 0.08%, have been studied. The critical NbC nucleus size, the rate of homogeneous nucleation, the temperature of the maximum rate of homogeneous nucleation and the time for complete precipitation were estimated in agreement between the calculated and experimental results. The precipitation-strengtheningseems to have optimum effect on the steels by isothermal precipitation for 1 h at about 600℃. Moreover, an improvement of the formula for the yield strength increment by the platelike NbC precipitates was also made. It is shown that, even the size of NbC precipitates down to 2.6nm, the mechanism of the precipitation-strengthening is still that of the Orowan's.
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    论文
    VOID NUCLEATION IN TENSILE DEFORMATION PROCESSES OF C-Mn STRUCTURAL STEEL——Ductile Fracture Mechanisms in a Structural Steel (Ⅰ)
    SHI Yaowu (Xi'an Jiaotong University); BARNBY J.T. (University of Aston; Birmingham; U.K.) (Manuscript received 21 March; 1983)
    Acta Metall Sin, 1984, 20 (1): 17-142. 
    Abstract   PDF (2468KB) ( 791 )

    Various methods which might be used to reveal the voids in the steel were compared. Using a series of the interrupted smooth tensile specimens with an incremental plastic strain, the void nucleation was investigated in a C-Mn structural steel with lower sulphur content. Based on the analysis procedure proposed in this work, the critical nucleation strain and relative void volume at the critical nucleation strain were determined.

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    ON THE VOID GROWTH OF C-Mn STRUCTURAL STEEL DURING PLASTIC DEFORMATION——Ductile Fracture Mechanisms in a Structural Steel (Ⅱ)
    SHI Yaowu (Xi'an Jiaotong University); BARNBY J. T. (University of Aston; Birmingham; U.K.) (Manuscript received 21 March; 1983)
    Acta Metall Sin, 1984, 20 (1): 24-33. 
    Abstract   PDF (1240KB) ( 605 )
    A procedure was proposed to establish a void growth relation with the plastic strain and stress triaxiality during the ductile fracture of a C-Mn structural steel. A multiplying factor on void growth was determined using smooth tensile specimen tests and pre-cracked side-grooved three-point bend bar tests. The factor was expected to be available to a rather wide range of the constraint. Based on the experimental void growth relation, the real void growth rate in the structural steel is slower than that determined by the Rice-Tracey's void growth theory, when the stress triaxiality, σ_m/(?), is larger than about 1.2. However, when the σ_m/(?) value is smaller than about 1.2, the void growth predicted by the Rice-Tracy's theory trends to sightly underestimate the void growth in the steel. Moreover, the variations of the plastic strain, relative void volume and stress triaxiality were measured and evaluated ahead of the blunting crack tip in the pre-crackcd side-grooved three-point bend specimens, when the ductile tearing initiated.
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    EFFECT OF ZIGZAG GRAIN BOUNDARY ON CREEP RUPTURE OF A 10Cr-15Co-Ni-BASE WROUGHT SUPERALLOY
    YE Ruizeng; GE Zhangying (Beijing University of Iron and Steel Technology); WANG Yueyi; DU Baoquan; LIAO Zhongyt; LI Lijia (Xindu Machine Works; Chengdu) (Manuscript received 23 December; 1982; revised manuscript 30 May; 1983)
    Acta Metall Sin, 1984, 20 (1): 34-144. 
    Abstract   PDF (2513KB) ( 655 )
    Investigation was made of the effect of the zigzag or straight grain boundary, which may be obtained by two different schemes of heat treatment, on the creep rupture of a 10Cr-15Co-Ni-base wrought superalloy, especially, on the reason whyits strength and plasticity at elevated temperature can be improved by the zigzaggrain boundary. It is shown that the zigzag grain boundary may delay the initiation, growth and propagation of crack, as well as may also influence the crack morphology and the fracture mode markedly. Furthermore, the zigzag grain boundary may intensively inhibit the grain boundary sliding and retard the crack joining, thus, force the bulk-grains to take part in more deformation. It displays an important role in the tertiary stage of creep. The creep life to failure of the alloy tested with zigzag grain boundary was increased by a factor of 1/4, and the plasticity was also improved slightly.
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    RELATIONS BETWEEN FAILURE BEHAVIOUR AND MICROSTRUCTURE IN TEMPERING STRUCTURE STEELS
    YU Xuejie (Shanghai Iron and Steel Research Institute) (Manuseript(?)eceived 16 August; 1982; revised manuscript 14 March; 1983)
    Acta Metall Sin, 1984, 20 (1): 41-146. 
    Abstract   PDF (2463KB) ( 655 )
    The relations between the microstructure and failure behaviour have been investigated in two structure steels by means of TEM etc. The results show that the appearance and disappearance of qusicleavage fracture after tempering are related to the precipitation and the distribution of Fe_3C. When tempering at 250℃, the carbide precipitated is ε-carbide. At the same time the fracture is dimple only. When tempering temperature is raised beyond 350℃, the Fe_3C precipitates and the qusi-cleavage of fracture also appears. The proportion of qusi-cleavage fracture reaches the maximum after tempering at 450℃. If the tempering temperature is raised again, the particles of Fe_3C coalesce and the fracture become dimple alone in 60Si2Mn steel after tempering at 550℃. However, the coalescence tendency of Fe_3C particles is relatively less in the 37SiMnCrNiMoV steel, so the qusi-cleavage fracture still exists after tempering at 550℃. Observation of microcracks retained in failure samples reveals that the microcracks always propagate along the twin boundaries of twinned martensites and along the lath boundaries of lath martensites. So it is suggested that these boundaries that were already made brittle may be the cleavage planes of qusi-cleavage fracture. The reason why they become brittle is due to precipitation and continuous distribution of Fe_3C along these boundaries.
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    EFFECT OF ESR ON CONSTITUTION NEARBY GRAIN BOUNDARY IN A Co-BASE SUPERALLOY
    DAI Tongfu; WANG Shuhe; SHI Changxu (Institute of Metal Research; Academia Sinica; Shenyang) (Manuscript received 2 August; 1982; revised manuscript 25 January;1983)
    Acta Metall Sin, 1984, 20 (1): 47-148. 
    Abstract   PDF (2013KB) ( 452 )
    The effect of the electroslag remelting (ESR) on the constitution nearby the grain boundary in a Co-base superalloy, Co-22Ni-22Cr-14W, during 760℃ aging has been investigated by Auger electron spectrum. Results show that the segregation of alloying elements toward the grain boundary is of various extents by the influence of ESR: the segregation of La may be decreased, and of P and S more markedly; That of Cr may also be decreased, but not obviously yet of W. At the beginning of aging, the segregation of C toward the vicinity of the grain boundary may be obstructed by ESR, and with the prolongation of aging time, it might be accelerated.
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    EFFECT OF Cu ON PRECIPITATION AND STRUCTURAL PARAMETERS OF Al-Zn-Mg ALLOY
    LIN Zhaoqi; ZHU Jiliang; SUN Guijing; YANG Shengkun (Northeast Institute of Technology; Shenyang) (Manuscript received 4 March; 1983; revised manuscript 12 July; 1983)
    Acta Metall Sin, 1984, 20 (1): 54-61. 
    Abstract   PDF (1160KB) ( 597 )
    The effect of a trace of Cu, about 0.19 wt-%, on the precipitation, the critical nucleation temperature, T_c~′, as well as the microstructural parameters of a commercial purity Al-S.0Zn-1.75Mg alloy has been studied by means of hardness test, optical microscopy and TEM. It was resulted that Cu, in contrast to Cr, is an element by which its homogeneous precipitation is promoted, the T_c~′ is raised from 150—160℃ to 170—180℃ and the hardness is increased, but the grain size is not yet refined and the recrystallization is not yet inhibited. Under the experimental condition of 120—200℃ aging, the grain boundary precipitation, the matrix precipitation and the precipitation-free zone of the Cu-contained alloy are minor to that of Cu-free one. All of these alteration may be monotoneous with elongation of aging time and elevation of aging temperature. Thus, it was proposed that the effect of Cu added on the precipitation and the structural parameters may he explained by a nucleation model which a complex cluster of the vacancy-tetrahedron combined with the segregated solute atoms, such as Zn, Mg and Cu, acts as a nucleus of GP zone.
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    INFLUENCE OF QUENCHING TEMPERATURE ON STRESS CORROSION IN 4330M STEEL——The Role of Impurity Segregation in Stress Corrosion Cracking of High Strength Steel
    LIN Dongliang (T. L. Lin); WU Jiansheng (Shanghai Jiaotong University) (Manuscript received 7 August; 1982)
    Acta Metall Sin, 1984, 20 (1): 62-152. 
    Abstract   PDF (4934KB) ( 1062 )
    The effect of quenching temperatures on the rate of stress corrosion crack propagation of 4330M steel in distilled water has been investigated. The rate of crack propagation, da/dt, decreased rapidly as the increase of quenching temperature in the range of 870—1100℃, while increased slightly from 1100 to 1200℃. The fracture mode changed from intergranular separation along prior austenite grain boundary in the specimens quenching at 870 and 1000℃ to transgranular quasicleavage in that quenching at 1100℃ and 1200℃. The segregation concentration of P at prior austenite grain boundaries has been measured with selective etching and found to be related to quenching temperature fitting McLean's theory of equilibrium segregation. The change of propagation rate with quenching temperature was found to be mainly due to the P segregation at prior austenite grain boundaries and can be rationalized with an interactional effect between H_2 and grain boundary P segregation. It is concluded that stress corrosion cracking of 4330M steel without grain boundary impurity segregation in distilled water is transgranular,while intergranular cracking is a result of impurity segregation at the grain boundraies.
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    KINETICS OF Mg EVAPORATION OF A Ni-BASE SUPERALLOY DURING VIM
    CHEN Enpu; SU Zhaoqian (Changcheng Steel Works; Jianyou; Sichuan); FU Jie; WANG Hui; WANG Di (Beijing University of Iron and Steel Technology) (Manuscript received 19 November; 1982)
    Acta Metall Sin, 1984, 20 (1): 71-77. 
    Abstract   PDF (530KB) ( 697 )
    The kinetics of Mg evaporation of a Ni-base superalloy, Ni-10Cr-15Co-6W-6Mo-4Al-2Ti, during VIM has been studied. It was indicated that the rate of Mg evaporation is simultaneously controlled by the diffusion of Mg through the liquid boundary layer and by the evaporation of Mg at the metal pool/atmosphere interface, rather than its diffusion through the gas boundary layer, when the furnace Ar pressure kept under 100—400 mmHg. The transfer coefficient of Mg evaporation K_(23) is 10~(-1)—10~(-2) cm. s~(-1) and K_4 is about 140cm. s~(-1). A simple mathematical model for Mg evaporation during VIM was proposed. This model provided that the predicted Mg contents are in excellent agreement with those analyzed in the experimental and industrial alloys. Thus, it is possible that the optimum Mg content may be accurately controlled by certain smelting parameters, such as, the amount of Mg added into the metal pool, the Ar pressure, the temperature and time of evaporation, etc.
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    EXPERIMENTAL STUDY OF CONDITION FOR BINARY AMORPHOUS ALLOYS FORMATION BY LIQUID QUENCHING
    LIU Zhiyi(Institute of Physics; Academia Sinica; Beijing)(Manuscript received 2 August; 1982; revised manuscript 19 November; 1982)
    Acta Metall Sin, 1984, 20 (1): 78-86. 
    Abstract   PDF (809KB) ( 593 )
    An experimental study was carried out on the formation condition of the amorphous state of binary alloys of transition metals. Intermediate phase (incongruent-melting compounds of lower melting temperature and congruent-melting compounds of lower melting temperature)might affect the formation of the amorphous state. A so called "deep eutectic gorge" composition tends more strongly to form an amorphous state. A new amorphous state of binary alloys Hf-Pd has been prepared.A typical structure of amorphous state in binary alloys Sm-Fe was obtained.
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    THE STRUCTURE RELAXATION SPECTRUM OF METALLIC GLASS
    DEN Deguo; YU Jian(Institute of Precious Metals; Ministry of Metallurgical Industry; Kunming) (Manuscript received 24 January; 1983; revised manuscript 30 June; 1983)
    Acta Metall Sin, 1984, 20 (1): 87-93. 
    Abstract   PDF (463KB) ( 601 )
    A proposed method for determining the structure relaxation spectra of five metallic glasses of Cu-Zr system has been carried out by measuring the electric resistance at constant heating rate. Three separate peaks of the activation energy with varied frequency factors were shown on the spectrum obtained, The frequency factor influences the shape, range, location and continuity of the peak. The Zr content in the Cu-Zr metallic glasses may affect considerably each own structure relaxation spectrum. Their variaty behaviour has also been discussed.
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    "SINGLE GRAIN" OSCILLATING CRYSTAL METHOD FOR ULTRAMICROANALYSIS BY X-RAY(Ⅱ)
    WU Qixing(Research Institute of Daye Steet Works)(Manuscript received 7 March; 1983; revised manuscript 30 June; 1983)
    Acta Metall Sin, 1984, 20 (1): 94-104. 
    Abstract   PDF (913KB) ( 528 )
    Three methods for the use of "single grain" oscillating crystal identification when the spots on the film were lacking or "residue" have been suggested, It makes the identification for superfine grains more exact and more accurate by finding out the matrix equation about the orientations in space and indices of crystallographic planes; by measuring the angles between the planes that can be represented by the spots on the film; and by taking down the number of the spots which belong to the same d value, in order to find out whether the "single grain" consists of a few crystals or of a multiphase substance. Attempts have also been made to revealing the presence of α-SiO_2 by these methods as well as to further verifying the proposed formulae and figures.
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    A NEW METHOD FOR DETERMINATION OF DIFFRACTION LINE POSITION
    ZHANG Lixin; LI Liguang (Institute of Metal Research; Academia Sinica; Shenyang)(Manuscript received 29 December; 1982; revised manuscript 25 April; 1983)
    Acta Metall Sin, 1984, 20 (1): 105-110. 
    Abstract   PDF (417KB) ( 483 )
    A new method for the determination of the diffraction line position was developed without relation to the diffraction profile. The precision in determination may approach to △θ±0.01°. It seems to be applicable to the precise determination of the lattice constants under the condition of broadening diffraction profile symmetrically.
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    ELLIPSOMETRIC ANALYSIS OF ION-IMPLANTED SURFACE LAYER ON METAL
    SUI Senfang; CHEN Heming (Qinghua University; Beijing)(Manuscript received 5 February; 1982; revised manuscript 22 July; 1983)
    Acta Metall Sin, 1984, 20 (1): 111-116. 
    Abstract   PDF (707KB) ( 681 )
    An ellipsometric method is prcscnted for the analysis of the ion-implanted surface layer on metal. Experimental results indicate that the variation of the pseudo-imaginary part of the dielectric function can give the information about the transformation from the crystalline into amorphous state of the surface layer on rectal by ion implantation.
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    PROPOSAL FOR A DIFFERENTIAL EQUATION OF TENSION IN TANDEM ROLLING
    WANG Guodong (Northeast Institute of Technology; Shenyang)(Manuscript received 23 April; 1983)
    Acta Metall Sin, 1984, 20 (1): 117-122. 
    Abstract   PDF (378KB) ( 537 )
    A differential equation of tension in tandem rolling was proposed as: dσ_(fi)/dt=E/(h_i integral from n=0 to L (dx)/(h(x)))(v_(i+1)~′-v_i) It seems to be satisfied for those rolling processes of both uniform and variant strip section. The equation may be simplified to one for uniform strip section if it operated through the stands uniformly. Based on the derivation and discussion of the equation an approach to applying the conventional tension differential equation for the computation of the rolling process of variant gage without introducing any error would be incorrect.
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    THE KINETICS OF SULPHURIC ACID LEACHING OF SYNTHETIC γ-NiS UNDER OXYGEN PRESSURE
    FANG Zhaoheng; XIA Guangxiang; CHEN Jiayong(CHEN Chiayung)(Institute of Chemical Metallurgy; Academia Sinica; Beijing)(Manuscript received 21 November; 1982; revised manuscript 4 May; 1983)
    Acta Metall Sin, 1984, 20 (1): 123-130. 
    Abstract   PDF (603KB) ( 400 )
    The kinetics of oxygen leaching of synthetic γ-Nis, or milerite, in dilute H_2SO_4 solution under oxygen pressure, below 4900 kPa, at the temperature range from 110 to 160℃ was studied. The leaching rate can be described by an unreacted shrinking core with no solid product formed on the surface. The rate of reaction can be reflected by the following equation: 1-(1-α)~(1/3)=(k/ρr_0)t=Kt The rate Constant K in the above equation can be expressed as: K=1.45×10~5(4.55+1/(?)_0)P_(O_2)~(1/2)[H~+]~(?)e~(-11720/T) The reaction rate will be retarded by tbe Cu and Ag ions in solution.
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    AN ACCURATE MATHEMATICAL MODEL OF ROLL FLATTENED ARC LENGTH
    SU Fengxi; JIANG Jinmei; CHEN Tianqen (Beijing University of Iron and Steel Technology)(Manuscript received 7 January; 1982; revised manuscript 27 May; 1983)
    Acta Metall Sin, 1984, 20 (1): 131-140. 
    Abstract   PDF (680KB) ( 580 )
    A method, so called "method of contact", was developed for accurately measuring the total length of roll flattened arc l', and the sectional length from the enter and exit to the centre line between the roll x_1 and x_0. An analysis has been made between the previously allied theories and the experimental results by the authors. It is verified that the less systematic error is resulted to compare with which increases as the decreasing reduction ε in Hitchcock' s formula. Because the error of arc length predicted from theoretical formula is mainly concentrated in x_0, its accuracy may be improved by correcting the calculation of this region. On the basis of consideration of the elastic displacements of rolls and strip, the equation of the roll flattened arc length may be geometrically determined and the correction factor for x_0 may be estimated by statistical analysis of the experimental data. Thus, a more accurate model of the roll flattened are length is proposed as: l'=(RΔh+(Ax_0)~2)~(1/2)+Ax_0 The prediction from this model together with the simplified Stone's formula to solve the roll flattened are length and separating force seems to be of superior accuracy.
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