Abstract: CaZrO3 containing the highest CaO colltellt of compounds in system CaO-ZrO2 is a potential refractory material. A satisfactory CaZrO3 raw material as formed from equimolar proportions of CaCO3 and ZrO2 subjected to two-stage synthesis:preparing first at 1450℃ and then refiring to 1 600℃. A close approach to theoretical density specimen was obtained with finely ground the raw material at 1700℃ sintering. By SEM the grains of CaZrO3 with perfect morphology was found to be linking closely in it.
Abstract: The behaviour of kyanite decomposing into mullite and SiO2 in different temperatures, different medium conditions and different grain sizes was studied. The experiments showed that the decrease of grain sizes can largely decrease the decomposing temperature and increase the decomposing speed. When the kyanite is contacting with a melt which produced in decomposing process, the decomposing temperature can be significantly dicreased and the decomposing speed can be largely increased.
Abstract: Mass flow process has been analysed in the zone of Blast Furnace and Converter. Three stages and two kinds of layout have been put forward about the development of it. The working procedure functions have been discussed. The changes of the zone layout and the importance of the joining and matching have been elaborated. The necessity and nature on the zone development have been summarized.
Abstract: The reduction of the synthetic and practice blast furnace slags with carbon at high temperature was carried out. Over 2123 K and 2173 K the SiO2 and MgO can all be reduced respectively, but at 2 273 K the Al2O3 will be reduced only 63%. In the increasing of MgO at constant basicity of the synthetic slag, SiC and SiO formed by reducing SiO2 in the slag can be increased and decreased respectively at the relative high tempeyature and enough carbon. By increasing the temperature and well mixing the practice slag and carbon, the reduction of oxides in the slag and Al2O3 in the reduced slag will be increased, SiC and MgO in the reduced slag will be decreased. The MgO in the slag can all be reduced at relative high temperature.
Abstract: The oxidation and decarbonisation behavior of high speed steel W9, M2, M2Al and D606 heated in the air were studied. The results showed that the weight loss by oxidation and depth by oxidation of four high speed steel increase in the air, When the temperature and times increase. The reasons of oxidation and decarbonisation behavior were analyzed. Influence of Si, W, Al elements on oxidation and decarbonisation of high speed steel were discussed.
Abstract: Process factors to effect of stability of electro-slag induct continuous casting of unidirectional solidification have been researched. Results declared that, position of solid-liquid surface is an impotrant target in measuring process stability, and process factor affected the process stability by this target. There are two key factors in process progressing steadily. The first is positive taper cavity of mold; the second is temperature distribute in mold wall.
Abstract: ZnO-Al2O3 spinel and the spinel-containing ceramics have been synthesized by sintering, the mixture of zinc oxide and alumina fine powder in various molar rations under about 1600℃. The contact angles between copper melt and the sintered ceramic samples of different compositions have been measured at the temperatures of 1200℃ and 1300℃. It can be shown from the result that the addition of ZnO into Al2O3 improves the wettabriity of copper melt on Al2O3 ceramic.
Abstract: Changes of oxygen and inclusion during electroslag remelting (ESR) of bearing steel have been investigated. Although the oxygen content in ESR steel is higher than that of continuous casting (CC) steel, the fatigue life of ESR steel is higher than the latter because of its less large size and well dispersed inclusions.
Abstract: In order to improve the adhesion of the diamond to the WC-6%Co insert substrate, boronizing approach from solid powder was adopted the first time to deal with the surface cobalt of the substrate. A layer of the CoB and CoB, intermetallic compounds chemically bonded to the substrate was yielded during boronizing at 1 000℃×4 h, and the layer can effectively prevent the diffusion of the cobalt up to the surface during diamond deposition; the layer can relieve residual styesses at the diamond-carbide interface too. The diamond coating on the substrate by boronizing pretreatment shows a further significant adhesion improvement.
Abstract: A method used to describe the stress-strain curve is firstly put forward. In this method, the influence of microstructure evolution is considered. On this basis, a new simulation method of microstructure evolution during hot deformation is also raised. Some key factors, such as the minimum local microstuucture volume and the minimum deformation incremental step are determined too. The prediction of mechanical properties after cooling is discussed subsequently. Finally, the two pass upsetting process of Q235 low carbon steel is simulated, and the test results agree well with that of the simulation.
Abstract: On the base of finite element simulation for one stand of 152.5BR passes system in stretchreducing mill, the distribution of equivalent plastic strain and tube wall thickness along the section is uneven. The position of maximum is located at the gap of roll. After changing the position at gap and root of roll and adding up, it results in polygonization of the wall thickness. Rolling tests for 152.5BR passes systems validate the result of finite element simulation.
Abstract: Effect of vanadium on continuous quenching bainite ductile cast iron and its existing condition have been studied. Effect mechanism of Vanadium on structure and mechanical property of bnainite has been discussed. It has found that vanadium exists in the forms of both solid solution and dispersion carbide in continuous quenching bainite ductile cast iron. Addition of vanadium to ductile cast iron can increase the nucleation rate of bainite efficiently, facilitate the bainite transformation, refine and strengthen the matrix structure, and raise its hardness. It showed that the vanadium can be used to replace Mo,Ni and B to produce BDI.
Abstract: The effect of total finish-rolling strain and pass strains on the precipitating behavior of TiC has been discussed, using the thermomechanical simulation technique. Results show that the total finish-rolling strain and pass strains have an important effect on precipitation behavior of TiC particles, and proper match of them would be benefit to get a sparse dispersion of coarse TiC particles.
Abstract: The exchange fields of NiO/NiFe bilayer have been investigated, and the NiO film is deposited by dc magnetron reactive sputtering.It has been shown that exchange field is relation to the ratio of Ar/O2 (Volume ration), total sputtering pressure and the roughness of substrate.The Ni and O ion in NiOx is analyzed by means of XPS.The spin-vavie Ta/NiO/NiFe/Cu/NiFe/Ta pinned by NiO is deposited, and its magne-toresistance reaches 2.2% and pinning field is 10.48 KA/m.
Abstract: With the aid of FE code MARC/Autoforge, a thermo-mechanical analysis of the tube round during two-roll rotary rolling process was studied. From the simulation, the field of strain and stress and the distribution of temperature are respectively obtained. The W-shaped distribution pattern of deformation on the longitudinal section of the round, which was obtained from physical simulation experiments, is further verified and the reason causing the W-shape is discussed in detail. Some divergences of views in the mechanism of center-crack forming are clarified, and a new distribution feature is discovered. The hydrostatic pressure in the center of the round is of positive larger value.
Abstract: The negative thermal expansion (NTE) in some complex oxides has been attributed to transverse thermal motion of A-O-M linkage composed of two-coordinate Oxygen bridge bond, and the librations and tilts of essentially rigid polyhedral blocks in open framework structure. The isotopic NTE materials have been finding more substantial applications in composites and other relative technique fields.
Abstract: Interference effect is used to improve solar performance of Al-N-O selective absorbing surface. Through experiments the film structure of two Al-N-O sublayers with different thickness and metal volume fractions is established. Compared with the graded films, the bi-sublayer films have lower emittance and better thermal Stability. The new films have been used in the mass production of heat pipe evacuated tubular collectors. High solar performance (α=0.93~0.95, ε(353 K)=0.04~0.06) have been obtained on the surface of the absorber.
Abstract: Two kind of the methods of realizing the corresponding supply of domestic cold-rolled sheet steel used for punch-formed car component were introduced, and the metrics and faults of them were analyzed. The modification measure was offered.
Abstract: On the basis of thermodynamic analysis, O'-Sialon-ZrO2-SiC composites were prepared. XRD and TEM were used to analyze experimental results,verify the thermodynamical calculation. The study on microstructure showed that the main crystalline phase is O'-Sialon which forms an interwoven structure and the interwoven structure is strengthen by ZrO2 and SiC for O'-Sialon-ZrO2-SiC composites.
Abstract: The hardness versus time curves during aging at 450-650℃ of Cu-Nb steels with various copper content have been measured. The precipitation of ε-Cu, Nb carbonitfide and Cr carbide found during aging contributes to the hardening. The result indicates that the Cr carbide hardness peak emerges after long time aging. The more is the copper content the earlier the hardness peak of ε-Cu occurs. In high copper steel the hardness peaks of ε-Cu and Nb carbonitride separates and in low copper steel they overlaps.
Abstract: The tension leveling process of the elastic-perfect plastic metal strip on the first bending roll is investigated. The conditions to form different patterns of stress distribution, the conditions to allow the metal strip Undergo plastic elongation, the calculation formula of the plastic elongation and the relationship among the elongation, tension and bending curvature or radius are discussed and clearly expressed.
Abstract: A kind of model of the optimum distribution of loads being holpful to shape control has been introduced on the base of the analysis of models used in tandem cold mills at present. And a simulating program has been built. The result of this program has been tested by the industrial experment.
Abstract: Based on the summarizing and analyzing of the theory of knowledge discover in database and the actuality of technological method, the trend of knowledge discovery in discussed and introduced the mechanism of total data mining process, researching in expansible structure and algorithm of KDD, and serially developing of software, according to the thetory of double base cooperation.
Abstract: A new fast learning algorithm for recurrent neural networks is proposed. By introducing the signal flow graphs technique, it overcomes the disadvantage of complexity of the gradient of the error function. And for more fast convergence, the BFGS method is used. Simulation results show that the proposed algorithm converges faster than the traditional algorithm.
Abstract: Given the change of characteristic parameters of the control object, the deterioration will be produced in the dynamic response qualities of the main drive system of a hot finishing mill. The optimization of PI parameters of the speed controller in a two-loop control system was studied, which is adjusted by iterative genetic algorithm. The digital simulation results show the efficiency and rationality of the algorithm.
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
