Abstract: Why and how the operations of ferrous metallurgical system should be optimized were studied based on the analyses of the current situation and the tendency of hot metal pretreatment technology in China4 The methods of system optimization were summarized and the application to ‘Blast Furnace-Hot Metal Pretreatment-Basic Oxygen Furnace ‘system and’ Raw Materials-Blast Furnace-Hot Metal Pretreatment-Basic Oxygen Furnace’ system optimized by means of dynamic programming were introduced.
Abstract: The tuyere annulus of hot metal pretreatment process was often blocked up by deposit carbon when light oil was used as coolant and the operation of tuyere cooling was very unstable. A new method was studied in which N2 and CO2 was blown with oil simultaneously, in order to prevent the carbon deposition from annulus and improve the stability of the tuyere cooling. This method is very effective for stable tuyere cooling.
Abstract: It is compared that dephosphorization reactions, slagmaking pa-thes, temperature curves, stoppings of combined blowing process under various blowing conditions in theory. On the basis of aboved, the most rational blowing rule fitting for current operating conditions is produced of Nanjing Iron and Steel Works.
Abstract: The wink net diagrams of cupola can be measured with fuzzy method, and the cupola was controlled with change searching blast steps. The investigation indicates that the control system is simple, has fast searching speed and good control effect.
Abstract: A mathematical model of air-water spraying cooling heat transfer in film boiling region is set up. With this model the heat flux and heat transfer coefficient can be calculated, when the air-water nozzle's water flux, droplet size and droplet velocity are given. The calculated results have a good agreement with the experimental datum.
Abstract: The phenomenological theory for the thermoelastic martensitic transformation suggested by the authors before is applied for Cu-29% Zn-3% Al alloy. The free energy function as well as the friction quasi-enthalpy and friction quasi-entropy, are obtained in SI units. Comparing with the clastic theory, the free energy can be broken into three parts: the chemical free energy, the interfacial energy and the elastic strain energy. In the range of 20%-70% M in the alloy, the interfacial energy per unit martensite formation is constant and the elastic strain energy per unit martensite formation is a linear function of martensite percent.
Abstract: This paper try to predict the formation of σ phase on the basis of thermodynamic equilibrium calculation. A power series model was chosed to express the excess free energy of multi-component non-ideal phase. All data including the interaction coefficient in binary and ternary alloy system were obtained by phase diagram fitting method. New method has the ability to predict phase formation correctly and enough precisely for all Ni-Co-Cr base sup-eralloys.
Abstract: The microstructure and properties of non-heat treated vanadium alloyed steel-40MnVS after controlled rolling have been investigated. The results showed that the strength and toughness are increases with accelerating cooled (from 0.1℃/s to 11℃/s) after rolling, because of ferrite grain refinement. The effects of finish-rolling temperature (from 850℃ to 1050℃) on the strength and ductility is unnoticeable, but the toughness is decreased clearly. When cooled speed is slower than 1℃/s, the toughness at room temperature are controlled by ferrite grain and its volume fraction.
Abstract: The mechanism and law of consolidation of the internal cavities of large forgings in J.T.S forging process were systematically investigated by high temperature modelling technique. The effect of J.T.S forging process on internal structure and mechanical properties was given. The resuts proved that this process could greatly improved the properties of large forgings.
Abstract: This paper gives an analytic method to determine the bending moment at the root of the gear teeth which may be looked upon as a cantilever plate with finite length acted by a concentrated load at arbitrary point of the plate face. The analytic method consists of the superposition of six cases ofplate-bending results which is more accurate than the traditional method-themoment-image method.
Abstract: In order to ensure that the rolling mill can produce high precision sheet strip with ±4μm thickness tolerence, the advanced control idea and method of all hydraulic push-up, censiant roll gap contrcol and computer synthesis are applied. The measures to take according to the various factors that cause thickness tolerence are discribed. At last, the curve of thickness tolerence in practical rolling process is given.
Abstract: A general relationship among the Gibbs free energies of intermediate compounds has been theoretically derived for n (≥2) -component systems. Accordingly it has been reached that the Gibbs free energies of intermediate compounds vary with the molar fractions of components in a certain regulation. In a binary system, the regulation is a quosi-parabola. In a ternary system, it is a quosi-paraboloid, and in n (≥4) -component systems, generally their regulations can not be geometrically descriced.
Abstract: A suggest has been advanced on using simultaneously the electrical conductivity and chemical and electrochemical stability of polyaniline for protecting metal conductive materials. The conditions for polymerizing compact and conductive polyaniline films were explored by electrochemical methods on a stainless steel anode in acidic aqueous solution. The polyaniline films obtained don't dissolve in NaOH or NaCl aqueous solution. The corrosion resistances of the polyaniline modified stainless steel were measured through polarization curves. In comparing polyaniline modified stainless steel specimens with unmodified ones the corrosion potentials in 3% NaCl and H2SO4 aqueous solution remarkably moved about 0.2-0.7 V towards the positive direction and were positive vs. saturated calomel electrode. The corrosion current densities were lower than those of 304 stainless steel and carbon steel about three orders of magnitude. The polyaniline layer would dissolve and fall off because of over-oxidation when the potential arose to 0.65V (in 3% NaCl aqueous solution) or 0.9V (in 0.5mol/l H2SO4). In 1mol/l HCl aqueous solution the polyaniline film was not able to offer protection for stainless steel specimens.
Abstract: The pitting corrosion of austenite stainless steels and alloy 800 in sodium chloride aqueours has been studied by the rapid scratch technique. The critical potential of the bare metal surface (Ec) obtained by the rapid scratch technique is an accurate potential value. The mechanism of pitting corrosion on the bare metal surface has been discussed and the physical sense of Ec has been proposed. Ec changes linearly with the logarithm of chlorion concentration. Ec is compared with breakdown potential (Eb) and protection (Ep) obtained by potentiodynamic technique. Ec and Eb change in the same way within a large pH range. In order to explain it, the coefficients of repassivation are measured.
Abstract: By means of the differential neck method, not only the effect of surface tension on the measurement of density can be solved completely, but the surface tension and density of melt can be simultaneously obtained in one experiment. A formula of this method is given. It is proved to be very correct by applying this method to water-alcohol solution and glycerol. The satisfactory result of the density of melt at higher temperature has been obtained.
Abstract: After comparing the sensitizing effect of various mixed surfactants on the chromophoric reaction of gallium （Ⅱ） with orthochlorophenylf luorone, it has been found that the mixed micelle of cetyltrimethylammonium bromide and Tween-80 is most suitable. In the presence of this mixed micelle, not only both the sensitivity and stability improve markedly, but also a wider pH range is tolerable for the colour-development. From the study on the optimum conditions for the formation of the coloured coordination compoundin the system of 《Ga （Ⅱ）——o-Chlorophenyl fluorone-catyltrimethylammo-nium bromide——Tween-80》 and its main characters, a spectrophotometricmethod, by which sensitivity and reproducibility are higher than those of ternary systems of gallium（Ⅱ） has been developed. When it is combined with the dual-wavelength method, the molar absorptivity can be improved to 2.33×105 l·mol-1·cm-1,which is higher than that of most of other systems ever shown in the literatures; moreover the linear range is extended. From the determination of microamount of gallium in the copper minerals, the result is proved to be acceptable.
Abstract: A new algorithm of solving integer linear programming is introduced in which the coefficients of the objective function are rational. This algorithm is called the modelling algorithm. In this algorithm, first of all, it can transform (ILP) into a special programming, then solve the special programming using a kind of special algorithm. The basic ideas of the algorithm is due to concentrating of the brance-bound and the cutting-plane, but it decreases the number of the branch and simplifies the technique of the cutting-plane.
Abstract: An excet frequency equation and formula of mode shapes for the beam restrained by any translational and rotational springs at its ends is derived. Many results in the past publication can take as the degenerate case of this equation and formula. The general formula also including several new results of elastically restrained beams.
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
