Abstract: A new way for making industrial pure iron is put forward. It includes three steps-hot metal granulation,solid state decarbonization and electric furnace melting down. The influence of time, temperature, mixture gas composition and granulated pig iron size on decarbonization ratio has been stuided. The optimum decarbonization index is obtained. The qualified industrial pure iron whose carbon content is below 0.025% has been made in laboratory. This new technique has evident economic benifit and provides a new way to explore new product for medium and small scale iron and steel works.
Abstract: Discusses the noise and its frequency band produced both by a 5t magnetic mirror bi-electic DC EAF and the same size three-phase AC EAF during melting period in the steelmaking workshop of Beijing Heavy Machine Plant, as well as the stable-constant magnetic field produced by a magnetic mirror coil. Compared with the three phase AC EAF, the DC EAF is an idel steel-melting equipment of steelmaking. The noise, which is mainly composed of high frequency,has been decreased by 15dB during melting period. Has used a DC EAF, artificial stiring is not necessary in whole operation because of its high stiring strength in melting pool. The arc is stable and has a certain direction in burning so the temperature in melting pool can be increased with a high speed (4-6)℃/min.
Abstract: The analysis of heat transfer situation of pulverized coal before pyrolysis was made inside the blast tube, and a math model was developed and solved with computer. The results show:(l)The situation of heat transfer before pyrolysis (espcially the radiation) is very important for quick pyrolysis of coal, (2) Pulverized coal lower than 300 μm is favorable, (3)The pulverized coal should not be regarded as thin wall.
Abstract: It is described the study of hardenability of 86Cr3 steel by useing Gleeble-1500 thermal simulator. This study has made a contrast test between jominy test and thermal simulate test. The result showed that the method of measuring the hardenability of a high hardenability steel by useing Gleeble-1500 thermal simulator is clearer and more useful than that by jominy test. The cost and test period are low and short respectively. So it can be used as new method for study of hardenability of high hardenability steel.
Abstract: The influence of alloy composition and microstructure on the yield-point elongation of continuous annealing cold-rolled dual phase sheet steel has been investigated. The experimental results denoted that the yidld-point elongation of cold-rolled dual phase sheet steel decreases with increasing the manganese equivalence and the Martensite volume fraction in alloy. In order to prevent the yield-point elongation occurring the manganese equivalence in alloy must exceeds 1.61%, and the threshold value of Martensite volume fraction is 7%.
Abstract: The relations between the magnetostrictive properties and microstructure, iron content.x of the alloy Tb0.27Dy0.73Fex(x=1.65-2.0) in as-cast have been studied. The matrix phase of this alloy has MgCu2 type structure. When x=1.90, the alloy in as-cast with small amount of second phase possesses a maximum values of λ11,λ11-λ and (dλ/dH)m. When x is equal to or large than 1.95, the RFe3 phase with Widmantanten-type morphology apppears, which leads to the decrease of magnetostrictive properties of the alloys. When iron content x is less than or equal to 1.85, the divorce eutectic structure or the two eutectic structure is observed, which causes the drop of the magnetostrictive properties of the alloys.
Abstract: A method of surface metallization of diamond, temper powder diffusion heat treatment, was developed. A powder mixture of elemental Cu (or Co), carbide-forming element Ti (or Cr) and diamond was heat-treatmented under vacuum. Carbide and metal film were formed on the diamond surface through solid diffusion reaction or diffusion reaction in presence of liquid phase. The bonding strenth of matrix material and the diamond was improved by using coated diamond. The bending strenth of matrix material with coated diamond was 9%-12% higher than that of matrix material with uncoated diamond.
Abstract: In order to use the technology of Computer Aided Roll Pass Design(CARD) to reform old steel plants, a computer aided roll pass diagnosis system was developed. Based on the Software Engineering, the system can diagnose all kinds of requirements in roll pass design and revise the wrong pass schedules. The practice showed that the diagnoses were correct, the revising was fast.
Abstract: Through the analysis on the rub characters between rolls of 4-high strip mill, the co-operation of small convexes between the backup and work roll is discussed. The axial displacement models are established on the touching surface between the rolls and between the work roll and rolling piece. With the predisplacement theory, the effect of the surface roughness of rolls, resistance to deformation and viscosity of rolling piece on axial force of rolls is analyzed. The theory formulas for axial force of the roll system of rolling sheep mills are obtained under the condition of symmetry rolling, and more complex axial force of work rolls is discussed. The axial force theory has been verified.
Abstract: Mechanical model of the drill carriage with rotation and vibrating hammer for the new type taphole drill is established. The natural frequencies and mode shapes of the model are calculated. The main parameter-push force, hardness of the material drilled, bit shapes and whether or not vibrating hammer, which affect the drilling speed and the relationship among the parameters are studied on the basis of experiment.
Abstract: The paper expounds that there is elastic press flat between the roller and workpiece during the wedge cross rolling and the flat will accumulate with the rolling continuity. The area of the press flat is attemptly calculated and some exprimental analysis to prove the theory of the accumulating effect of elastic press flat is made.
Abstract: Due to the application of the theory of artificial intelligence and knowledge engineering, the traditional system for trouble shooting has become the deep knowledge-based expert system. This expert system and expert system for machine design use the same object model, stratum structure and functional frame to make inferences of design, explore the optimization for design plan and in terms of deep knowledge to acquire causality for trouble shooting, looking for troubles of equipments and their generating reasons. Thus the two kinds of expert systems which were independently existing and proceeding in the past time can be in perfect harmony and has become the intergrative expert system for trouble shooting and machine design.
Abstract: An envelope method based on the theory of envelope with double-parameter is detailed. When the boundary surface of the work-space is determined, process of its forming is divided into two parts. The method is intuitive and easy to use graphically. Finally, an example to illustrate the method is introduced.
Abstract: The design and implementation of φ450mm narrow hot strip mill looper height computer control system is discussed. It involves the control principle, hardware and software of the computer system, dynamic structure diagram, control algorithm and other several special problemes related to looper height control.
Abstract: Adding a resonance link to the traditional PWM inflexible switching circuit, a voltage-source inverter of high frequency and no switching less was formed. Compared with current PWM inverters, this circuit has the advantages of high frequency, low noise, low switching-loss, little system volume, low electromagnetic interference, quite good output wareforms and no need of damping circuit.
Abstract: The equations describing the limit current in the normal diffusion region or knudsen diffusion region are estabished from the viewpoint of thermodynamics and kinetics. The factors, which influence the limit current in above regions, that is, oxygen concentration, temperature, gas diffusion coeffience, pressure, and geometric parameters (area and length) of the diffusion hole are theoretically considered. The response time equation of the sensor is formulated as well.
Abstract: The surface electric resistivity of composite coatings of CF-varnish, surface treated CF-varnish and Cu-plated CF-varnish is measured. The relationship of surface resistivity with CF contens in coating and the number of coatings is determined. Micro-morphology of above-mentioned three types of coating is observed and their electric conduction mechanism is discussed.
Abstract: The interlayers of chemical vapour deposition (CVD) of TiN on three iron and steel samples were studied. It noted that the interlayers were formed by diffusion of Ti and N which could penetrate into iron and steel across the TiN coatings. Carbon, contained in steels, also diffused towards the outer coatings, and this process could increase the depositing rate of TiN. Because the diffusing rate of N in γ-Fe was much higher than that of Ti, Fe2N+x-Fe and Fe2N+Fe2Ti+TiN+x-Fe were formed while TiN was depositing on pure iron.
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
