Abstract: In this paper, the standard Gibbs energy of formation of liquid FexO was determined by using the oxygen probe with solid electrolyte and the error analysis of the method was done. The formula for measuring △G° of FexO was introduced, which is in good agreement with interature data.
Abstract: The Oxidized relation between Mn and P in pretreatment of hot metal containing low Si, high Mn and mid P by using lime-based flux was investigated. The results show that when﹝%Mn﹞ is above 0.32, Mn is more preferential oxidized than P, and when﹝%Mn﹞is low 0.32, the result is contrary to one above mentioned at 1573-1623K. The Mn content which is low 0.3% in hot metal is necessary in order to obtain the sufficient dephosphorization.
Abstract: This paper introduces experimental results of the ESM of cast iron in the laboratory and pilot-plant based on predecessor's work. The results show that the desulfurization, inclusion removal and gas elimination of the ESM have obvious effect on making iron liquid purified and producing high quality casting, and indicate that the ESM of cast iron may essentially improve the traditional process of cast molten iron melting as a new technique for making high quality spheroidal-graphite cast iron.
Abstract: The nodualization effect of cast iron treated by rare earth alloys was compared with ones treated by magnesium alloys. As the ratio of residual rare earth content to residual Mg in cast iron is 3:1, the same nodu-alization effect will be obtained. A proper composition for rare earth sphe-ro idual graphite cast iron is as C ≤ 4.0%, E.C ≥ 5.0%, S<0.01%, RE ≥ 0.1%. and there is no defference in chilling tendency between RE-SG and Mg-SG.By means of injecting rare earth powder, the speed of reaction of desulphurization is higher, and the limit of dcsulphurization is close to the thermodynamic equilibrium. If the amount of RE to be added into liquid iron is properly controlled, desulphurization,nodualization and inoculation can be finished at a time
Abstract: The thesis focused attention on structure and property of the wedge horizontal rolling motor axis which made of medium carbon microalloy steel (35MnVN). The fine ferrite-pearlite structure in motor axis was obtained in air-cooled treatment after the rolling. The main properties are:σb=870-900MPa, σs (ie σ0.2)=759-796MPa, ak=69-13d J/cm2.
Abstract: The materials investigated were a 40Si2Mn2Mo steel and two kind of 40Si2Mn2Mo steels with different molybdenum content. By means of TME and physicchemical phase analysis technique, it has been found that there exists a transition from e-carbide to cementite in the tempering temperature range corresponding to TME in 40Si2Mn2 steel.Nevertheless, the cementite precipitated at this stage of tempering is not platelets as generally observed in other steels, but is fine dispersive particles. The correspondence between the fine dispersive carbide and TME is confirmed in 40Si2Mn2Mo steels. It ha.s been concluded that a large amount of line dispersive cementite precipitating during tempering is a primary factor for TME in medium carbon Si-Mn steels.
Abstract: Support Syftem of sink Field Theory (3SFT) for process modclling of stamping deformation is developed. It includes simplified date-base, modelbase, functionbase and control language. By using 3SFT, the modelling computation on deep drawing process of reentrant contour shell has been operated, Blank contours, strain rate distribution and computer modelling of deep drawing process is obtaind in blueprint.
Abstract: Picture analysis method is used to measure and analyze the carbide distribution in the high-speed steel shaped by radial forging machine. The method can remarkablly reduce the error caused by using the comparing pictures of carbide degree to appraise the quality of high-speed steel. Following four factors are measured:(1) area percentage; (2) average area of grain; (3) average free distance; (4) length-width ratio. Based on these factors, the process of radial forging is discussed and the relationships between the factors and accumulated deformation degree, or the final deformation temperature, are oblained. The increase of the accumulated deformation degree and a reasonable amount decrease of the final deformation temperature (860-910℃) are favourable for the fineness of carbide.
Abstract: As of the characters of 3-roll stand, and through relation of geometry, applied formula of the pass designs and parameters of oiling force and touque for 3-roll stands are deriven.
Abstract: The analysis of tension AGC system in the tandem cold mill shows that it is a time-varing dynamic system, so that the minimum variance self-tuning regulator is used. After the system is identified and simulated, the results how that the control effect of self-tuning regulator is better than that of PID regulator and the recursive least square with forgetting factor is a better identification algorithm. The application of self-tuning regulator in an actual tention AGC system shows that the gauge deviations of the controlled strip are greatly decreased.
Abstract: A new way for detecting gear fault by signal processing is proposed, which is called TFF (Transient Frequency Fluctuation) analysis. The technique is based on the Time Domain Average and Hilbert Transform. Much analysis is made oa the modulation of gear vibration signal due to defects. Through FM demodulation, the frequency modulation signal TFF (t) can be extracted which is consistent in relation to gear defects. Experimental results show that the proposed approach can give earlier indication of gear malfunction than other conventional methods.
Abstract: Using electron microscopy and X-ray diffraction techniques, the structure changes of Fe-Cr-Al alloy being used at low temperature for a long time were investigated. The results demonstrated that increase in embri-ttlement for the alloy was mainly caused by grain growth and α'-phase precipitation which contained 75 at% Cr; as usual, Small amount σ-phase and carbide Gr23C6 precipitated at grain boundaries.
Abstract: The effects of the deposition temperature on the chemical vapor deposition (CVD) rate, the bulk hardness value of TiN deposite and the hardness and the dimension of the steel base were investigated. TiN film obtained at temperatures between 950 and 1000℃, were stoichiometric composition, golden-yellow in color, and the high hardness (Hv1≈2000N/mm2). The hardness and dimension of the steel base depend on the deposition temperature. The variety of dimension for the steel base is less than 0.0005 if it is tempered after deposition.
Abstract: A computer program has been developed for calculating the phase diagrams of predominance areas (LOGPo2-LOGPs2, LOGPo2-LOGPso2 diagrams) by the use of the method of linear programming. The concrete equilibrum relationships of thermodynamics between substances in the LOGPo2-LOGPs2, LOGPo2-LOGPso2 diagrams has been described mathematically and all the problems of thermodynamics have been changed to the problems of linear programming completely, The general computer program of the calculation for the LOGPo2-LOGPs2, LOGPo2-LOGPso2 diagrams has been written by the use of the Revised Simplex Method which is employed for the computer to solve the problems of linear programming. This method is considerably simpler, more clear and reliable in mathematical model than previously reported methods and make use of the method of linear programming to determine the predominance areas of substances.
Abstract: This report studies on polarization behaviour and A.C impedance character of pure chrome in nuetral solution of H3BO3-Na2B4O7 and in redox solution of H3BO3-Na2B4O7 + K3Fe(CN) 6/K4Fe(CN) 6 by means of polarization curve and impedance techniques. A discussion on electrode reaction and electro-model of passive film are completed.
Abstract: In this paper, the equation between the heat of fusion of the pure metals and its particle size are deduced by means of the thermodynamic method. The size effect on the heat of fusion is formulated. The equation has been proved by a series of calculatioas from the thermodynamic data of some metals. The heat of fusion of metal powder of the high dispersity is smaller than that of non-dispersity.
Abstract: In this note we extend Marcinkiewicz interpolation theorem to the case of operators from Lp(Lq) to LP, and then use it to extend Hardy-Littlewood maximal theorem to Lp(Lq) spaces.
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
