Abstract: The fundamental parameters, the average chemical composition and the petrochemical models of the continental crust in North China are presented. The total mass of this crust is 1.5×1017t It is mainly composed of 13 elements, and the total weighted abundances of the silicon, aluminium and oxygen are 82.75%. The volumetrical abundance of oxygen is 94.2%. In each cubic kilometer of rocks in this crust, there are 210×106t aluminium, 132×106t iron, 8.7×106t titanium and 2.2×106t manganese. The calculation and usages of the petrochemical models shown by weighted abundance, volumetrical abundance and relative abundance respectively are also paid attention.
Abstract: By using dynamic photoelatic method, the dynamic stress field in semi-infinite elastic medium due to contact explosive loading was studied. More emphasis was placed upon the comparison of the transient stress distributions in a finite plate under two kinds of loading conditions: charges concentra ted on one side of the plate and charges symmetrically placed on two opposite sides of the plate. The test results indicated that when using same amount of charges, symmetrically placed charges could stimulate stress concentrations in certain parts of the plate and therefore cause the plate to fracture.
Abstract: Based on numerical methods, a mathematical model of two-dimensional unsteady heat transfer is developed to simulate the heat transfer of killed ingot, and verified by the experiment measurment in a factory. In the model, the temperature of the solidus is a metallurgical index, and the parameters of system and operation are considered. So it is possible to consider the effect of cap section, heat agent, and operation on killed ingot solidfiction in the whole.
Abstract: In accordance with the coexistence theory of slag structure, CaO-SiO2 and CaO-FeO-SiO2 phase diagrams and corresponding thermodynamic data, a calculating model of mass action concentrations for CaO-FeO-SiO2 melts at 1 600℃ has been deduced. The calculated contours of iso-mass action concentration NFeO are fairly identical with the contours of iso-activity αFeO measured. The apices of iso-NFeO contours are located at the range of slag basicity 1.703 to 1,778, so for the decarburization and precipitation deoxidation the slag basicity had better be kept in that range, and on the contrary for diffusion deoxi-dation the slag basicity had better be kept off that range. Similarity of iso-silicates mass action concentration contours to the corresponding iso-thermal contours of CaO-FeO-SiO2 phase diagram shows that silicates play an important role in the melting temperatures of slag system mentioned.
Abstract: For making powder alloy, the riscosity and surface tension of liquid alloy are analysed and determined. Different atomization processes are put into operation in laboratory scale. A complex process of argon atomization and air cooling showes to be suitable for that purpose. The product of rare earth alloy powder is with a sizes of 0.2mm~2.0mm and good fluidity. For analysing the mechanism of atomizing process, a high speed photographic technology is used.
Abstract: According to the finite element analysis of heat conduction with phase-change by using the enthalpy, an effective numerical method to eliminate the solution of iteration is presented. It overcomes the disadvantages of the former numerical methods, and it is shown from the new numerical results that this method has the characteristics of high accuracy and needs less calculating time.
Abstract: Cyclic stress-strain behavior in pearlitic and tempered sorbitic eutectoid rail steels has been studied by Incremental Step Test technigue. It is shown that tempered sorbite exhibits only cyclic softening and simultirieous cyclic softening and hardening are observed in pearlite throughout the entire range of strain amplitudes investigated. Cyclic stress-strain properties in coase structure and pearlite are better than those in fine structure and tempered sorbite respectively. Critical strain amplitude of pearlite has been defined. The effects of properties on critical strain amplitude, and the relationship between microstructures, incremental step strains and cyclic stress-strain parameters have been investigated.
Abstract: For the purpose on application of direct aging (DA) GH169 in production a comparison of direct ageing treatment and standard heat treatment following hot deformation is conducted. Direct ageing treatment can get higher tensile strengthes and raise smooth specimen stress rupture lives remarkably. However, both notched specimen stress rupture aud cyclic stress rupture lives decrease because of the low ductility. The creep damage during creep and fatigue interaction condition is also enhanced. The reason may be smaller amount δ precipitate distribution at grain boundaries and the grain boundary cohesive force can not perfectly match grain strength, then the strengthening and ductility improvemeat can not reach simultaneously. Grain refinement and dislocation configuration control at the hot deformation process are most important factors to control the suitable amount and distribution of δ-phase.
Abstract: The method combined numerical calculation of temperature field with modelling experiments was used to analyse and compare the internal temperature gradient distribution and the change of large forgings caused by air-cooling and spary water cooling in J. T. S. forging process. The optimum internal temperature distribution of large forgings and effective way to get the optimum temperature distribution were investigated.
Abstract: Presents a new method for synthesis of types of manipulators and determination of their structural parameters in mechanical system design of robots. The method which is called step-by-step sizing and optimazation contains a set of systematic procedures on the besis of objective consideration. It has been applied to new design of manipulator of robot and proved to be effective.
Abstract: The reconstruction of the roll eccentricity signal is completed by means of data sampling and statistic processing. The modification of the roll eccentricity signal is completed by way of iterative computation. An on-line detection and an on-line control method for the back-up roll eccentricity is realized. The construction of the control system and the result of simulation is given.
Abstract: The electric resistance behavior of pitch-base preoxidized fibers during the carbonization is measured. The conclusions have shown that the fiber's resistivities during the carbonization decrease from 1012 Ω-cm to 10-1 Ω-cm. And the quantitative relation between the fiber's resistivities and the carbonized temperatures is got. Using the relation of fiber's resistivities and the results of fiber's element analysis infers the constructive changes of the fiber during the carbonization. The example of the carbon fiber's electric conductivity used has been given.
Abstract: The kinetic effects of different rare-earth additives on the oxidation resistance of Ni80Cr20 electrical heating alloy at high temperature are studied through thermogravimetry under the condition that the residual content of rare-earth is fixed. The apparent activation energies and the rate constants of oxidation reaction are calculated in the range of 1 050-1 200℃. The mechanism of oxidation is discussed. The structure, composition, and the adhesion of the oxide films are investigated by X-ray, metallograph etc. The mechanism of the oxidation resistance of Ni80Cr20 alloys with different rare-earth additives is also discussed.
Abstract: The factors affecting the voltage-time transients of anodic electro-deposition of porous anodic films on aluminium in (NH4)2MoS4 solution at various constant current densities have been studied. EPMA analyses reveal that the deposited solid lubricant distributes in the whole pore profile and has higher content in the region near the outer surface of the film. It is suggested that the DC anodic deposition process is a reanodizing process. The thickness of barrier layer increases with the rise of the voltage during reanodizing. The ratio between the thickness of barrier layer and the applied voltage is in the range of 1.0~1.4nm/V. No initiation of larger pores and cells corresponding to the higher voltage was found in the newly developed barrier layer. The films with MoS2 deposition have lower friction coefficent and higher wear resistance, but its hardness is lowered.
Abstract: This paper studied corrosion behavior of plating foils depending upon the technic condition of amorphous Fe-Ni-P alloy electrodeposition. In acid solutions, the Tafel polarization curves were measured. The results indicated that the amorphous Fe-Ni-P alloy coating had better corrosion resistance behavior. After attached in HC1 solution, the electroplating foil was researched with AC impedance system for corrosion process.
Abstract: The experiment and numerical analysis of biaxial thermal stress fatigue under various stress ratio.The results show that the morphology of thermal fatigue cracks depend on both ratio of two principal stresses and ratio of two principal plastic stress, and the direction of straiight crack is perpendicular to the direction of maximum principal stress. Netty thermal fatigue crack will occurs when two principal stress and two principal plastic strains are approximately equal to each other.
Abstract: A VNi atomic model for 3D periodic structure is posed based on T polyhedrons which are introduced. The fourier transform patterns of the atomic model may explain the 12-fold symmetry in electron diffraction patterns of V60Ni40 alloy. This is the first satisfactory explanation since the V60Ni40 alloy has been reported.
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
