Abstract: Spraying mechanism of cooling water using 3/8" BD3 type nozzle in continuous casting machine is investigated. Theoretical formula of the effect of the nozzle structure on angle of spray cooling water is induced. The result obtainted from the formula agree well with practical ones. Based on discussing influence of the nozzle structure on angle of spray cooling water, the method to increase volume of the cooling water is proposed.
Abstract: The effect of changing the fluidized-bed temperature, fluidizing velocity and the bed height on performance is discussed in detail in this paper. Measured performance characteristics include gas rate, steam conversion, volumetric gasification intensity and gas quality. The distribution of contents of gas and the distribution of temperature along the height of fluidized-bed are achieved under different operating conditions.
Abstract: Some typical aerodynamic flow patterns that related to industrial furnaces have been successfully photographed by using the helium bubble tracing technique. The apparatus and the bubble solution are made in the laboratory of BUIST. By using a multi-exposure method more stream lines were catched in the focus, it is especially useful for studying the air flow pattern mainly affected by the jet from a coal water slurry burner, or a RK type oil burner.
Abstract: Iron-base GH132 and nickel-base GH33A were selected as two typical superalloys to study creep and stress rupture under complex stress condition at 650℃ and 750℃ respectively. Cyclic stress rupture tests indicate weakening of two superalloys. Cyclic stresses superimposed at creep tests decrease creep fracture lives of both superalloys, but secondary creep rates are generally still controlled by means of stresses at dynamic creep tests, when the amplitudes of superimposed cyclic stresses are not very high.
Abstract: Cyclic creep tests were conducted in an iron-base superalloy GH132 at 650℃ and constant maximum stress （46kg/mm2） with different minimum stresses（10,23 and 43kg/mm2）. Deformation at cyclic creep is complicated. Beside elastic and plastic deformation, an elastic deformation occurs at cyclic creep. Deformation behaviour at cyclic creep depends on stress amplitudes and minimum stresses.
Abstract: The effect of iron（0-25%）on the sigma phase preciptate kinetic and properties of a Ni-Cr-Mo-Al-Ti alloy by different heat treatment has been investigated. It was shown that sigma phase formation is related to iron content. Iron as alloying element could change the partitioning ratios of alloying elememts between γ-γ’ phases and increase average electron vacancy number Nv, and thus promote sigma phase to precipitate. Stress rupture strength of alloy is decreased in increase of iron content, but its effect on tensile properties is little.
Abstract: In this paper, annealing effects on the curie temperature （Tc） in amorphous Fe-Cr-B-Si alloy have been investigated by using the curie temperature measurement apparatus specially for straight ribbon samples. Logarithmic dependence of the increment of Tc upon annealing time（t）has been obtained from computer fitting, and two processes in structural relaxation causing changes in Tc have been discussed.
Abstract: In this paper, the influence of adding Mo,Cr3C2 and C on the structure and properties of WC-Fe/Co/Ni hard metal has been investigated. The paper has also discussed the effect of heat treatment on the structure of binder phase and the properties of the alloy. The experimental results showed that the properties of WC-Fe/Co/ Ni alloy can be improved by closely controlling the composition of the alloy and the addition of alloying elements and by heat treatment. The combination propeties of WC-Fe/Co/Ni alloy was better than that of the WC-Co alloy.
Abstract: This article has studied that both of the finish rolling temperature and cooling speeds after hot-rooling influence on the microstructure and mechanical properties. Experimental results demonstrate:1) appropriately reducing finish rooling temperature will improve mechanical properties of 16Mn steel plate. 2) as cooling speeds increasing after hot-rooling, strength of steel increases obviously,when cooling speeds between 5℃/s and 22℃/s. The plasticity and ductility come up to the standard value, at cooling speed of 5℃/s, 15℃/s and 38℃/s, yield-strengths make the grade of 35kgf/mm2, 40kgf/mm2 and 45kgf/mm2; respectively. Therefore controlled cooling after hot rooling is an effective method for increasing strength-ductility of 16Mn steel.
Abstract: In this paper, mathematical model is proposed for describing the flow field in liquids or melts agitated by a symmetrically placed impinging gas jet. The problem is formulared by the statement of the axi-symmetrical turbulent Navier-Stokes equations using k-e model for the eddy viscosity. The differential equations are solved numerically using a technique described by Gosman and Spalding et al. and the computed results are shown to be in satisfactory agreement with experimental data both in previous and present investigations. Due to the improvements made in the model, the predicted results are closer to the than those in the previous study by Li Yuzhang et al. Experimental data, furthermore, the present model may be used to describe the fluid agitated by an impinging gas jet with more extensive range of gas flow rate. In general, this paper may be considered as a continuation and extension to the work which has been done by the previous investigators.
Abstract: The studies ot copper-tin intertnetallic compounds growth rates at the interface of the copper substrate and tin or lead-64-76% tin coating were conducted in this paper. The thickness of intermetallic compound layers formed with a variety of aging time at 100±1℃ and 155±2℃ had been measued. The dependences of the intermetallic compound thickness on time and temperature were shown. It had experimentally been observed that the growth rate of compound in lead-tin coating at near eute-ctic point is faster than that in purely tin coating. The compound layers have not been detected on the leader which had been stored at room temperature for about a year. In addition, the relationship between the remaining coating and the solderability of leader was also discussed.
Abstract: In this paper, several sufficiency condions to determine asymptotic stability of a large-scale system with variable coefficients are psented,i. e theorems 1,2 and 3 by using the norm of vector and matrix and scalar Liapunov functions. Then the stability parameter regions of theirs are compared with each other and the proof is given theoretically.
Abstract: In this paper, we presented that the obvious differences between the fracture angle of the complex fatigue crak and that of the brittle fracture crack are not only superficial but also substantive,especially in some particular crack states,for instance, some fatigue cracks don’t propagate along the direction of their original cracks in the condition of pure type I （K11=0）.On the contrary, they do so in the condition of complex type （K11≠0）. Besides, the growth rates da/dN of the crack between complex fatigue and pure type I fatigue have different regularities. It appeared that their criterions shoudn’t be identical.
Abstract: The Sulfatization of manganese ore from Dongxiangqiao Region was investigated in a small quartz reactor with synthetic gas mixture of air and sulfur dioxide. The influence of temperatu re, reaction time, fineness of the ore, addition, concentration of sulfur dioxide in the gas mixture, etc. On the recovery of Mn, Co and Ni was studied systematically. It is recommended that the ore be milled to 95%-200 mesh and pilletized with 2-3% sodium sulfate, heated for one hour at 400#: and two hour at 700# in the gas mixture and the cooled mass be digested with water. Under these conditions mentioned above, the recovery of Mn, Co and Ni was above 90%, 80% and 60% respectively.
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
