Abstract: Two linear programming models are discussed for ore quality control in underground mine production planning. The models were solved by microcomputer and applied to Xishimen Iron Mine.
Abstract: The Nb extraction process in Baotou Steel Company is a process accompanied with the iron and steel-making process, in which the blast furnace smelting is one of the main step of extracting Nb. It was discovered by experiment that niobium oxide could be turned into niobium carbide(NbC) during carbonthermal reduction and the detained NbC layer exised at the metal-slag interface. The existence of tne detained NbC layer obstructs the entering of Nb into iron and has bad effects on the Nb recovery ratio. NbC can dissolve into liquid iron. Raising temperature is favourable for the increasing of the solubility of NbC in iron and the raising of Nb recovery ratio.
Abstract: By hydrodynamic model experiments, the effect of topblown gas, bottom blown gas and CO gas on bath stirring in 150 t top-bottom converter were studicdt According to method of orthogonal experiment design, the essetial factors and optimal amount of top and bottom gas were found. At high carbon range, compared with the stirring by CO, the stirring by top and bottom blown gas could be neglected; at low carbon range, the stirring by bottom blown gas was the main factor. The optimal gas amound was about 5 Nm3/h. The equations of mixture time and rate constant of mass transfer were established.
Abstract: The high toughness ductile cast iron directly obtained at as-cast state had been studied. It was found that the content of Si and Mn were the main factors affecting the amount of ferrite and the value of δ% under the good state of graphite spheroidization. The value of δ% raised with the increasing in amound of Si and the decreasing in amount of Mn. When the amount of Si was in the range of (2.90-3.20) wt% and Mn in the range of (0.15-0.40) wt%, the value of 6% reached (19-21)%. This kind of as-cast high toughness ductile cast iron has been successfuly used in producing heavy section castings and thin section castings.
Abstract: Some special temperature points of hypereutectic molten iron in cutectic reaction (for example, the lowest, the highest and the end eute-ectic reaction temperature) can be measured by the short respose time thermal analysis cup, when it solidifies into grey iron. The special points can be used to forecast the silicon. The forecast precision is high enough to guide the increasing in silicon in the blast furnace molten iron.
Abstract: On base oi some reasonable hypothesis and by connecting theorcli-eal inferring with experiment, a pipeline transportation mathematical model (including thixotropic-rheological model and energy loss model) of CWS has been built. Energy losses, frictional coefficient and the optimum economical pipeline diameter at different flow rate of CWS can be revealed by solving the model. Practical application of pipeline transportation of CWS has proved that this model is correct and reliable.
Abstract: A detailed fractographic analysis was performed on a nickel-based superalloy under complex loading with superimposed compressive peak overload at 700℃. The fatigue cracks were observed to be presented in semicircular striations with relatively wide spacing. The measured fatigue crack growth rate da/dN from the fractography was found to be related to ΔK in the way of paris formula. It also indicated that fatigue cracks were not propagated continuously by extending a long crack but by a successive process of "stimunated nucleation at the front of crack tip" and "jump connection" with the main crack. Under the effect of the superimposed Sp there were three different types of "step" morphologies observed on the fracture surface, a crystallographic orientation relationship in the morphologies were proposed. The mixed fatigue and creep morphology reflected the influence of their interaction at high temperature.
Abstract: The Ce and P cosegregation on the grain boundaries in a-iron was studied by Auger Electron Syectroscopy (AES) and computer modelling method. The result shows that in case of low P content in the alloys (P<0.07wt%), Ce reduces the grain boundary segregation of P, but in the high P alloys (P>0.10wt%), Ce enhances the segregation of P. The computer modelling of this phenomenon indicates that the segregation structure of Ce and P on the grain boundary varies with the change of P content on the boundary. The main reason of the change of the interaction between Ce and P on the grain boundary is that the lowest energy structure of Ce-P cosegregation varies.
Abstract: Structure of inclusions in isotropic pitch-based graphite fibers have been investigated by using TEM. The longitudinal sections of most inclusions are shoe-shaped, ellipsoidal or circular. These inclusions have layer structure which consists of a number of flaky crystallites. Theses flaky crystallites are parallel to each other and perpendicular to the fiber axis. Fissures which are perpendicular to the fiber axis have been found inside the inclusion.
Abstract: As an attemp, fuzzy cluster analysis in data treating of top-and bottom blowing steelmaking tests is applied. The relations between (%ΣFeO), Lp, La, of slag and the intensity of bottom blowing have been established qualitatively. It has been shown that those slag-indices are strongly enflueced by the intensity of bottom blowing.
Abstract: A new method for predicting the surface tension of ternary from biliary ones by using geometric solution model is given. Binary excess surface tensions are fitted by means of rational function method, and ternary excess surface tension are calculated using R-function method. That makes not only the calculaiton time to be less, but the results to be more accurate. This method was appliced to the Cu-Ag-Au system, and a good accordance was obtained between the calculated and reference values.
Abstract: The shape memory effect(SME) in Cu-Zn alloy was studied by the twisting deformation method and electric resistance methods. The results show that when the temperature above Ms, there is no thermoelastic mar tensite(TEM), but show perfect SME, so that the SME is entirely caused by stress-induced martensite (SIM). On the other hand, when the temperature below Ms, though there is TEM transformation, the SME is also mainly caused by the SIM.
Abstract: The variations of the saturation magnetostriction constant and the magnetization-flux of the metallic glass Fe39Ni39Si8Bl2Mn2 were studied using the tension-magnetization with a large angles rotation during aging at room temperature after charging hydrogen. The results show that with the decrease of saturation magnetization, the increase of anisotropic constant and the smaller value of saturation magneto-striction constant are induced by hydrogen in metallic glass.
Abstract: On the basis of Hasselstron and Chone's work, a new formula for calculating the liquid slag thickness between the slab and mold in continuous casting process is deduced in terns of the knowledge of fluid mechanics. In comparison with the former formula, more factors have been considered in the equation. Therefore, it is expected that this formula will give a better result in the determination of technical parameters and the selection of the slag compositions.
Abstract: The setting processes and phase compositions of four MgOMg-Cl2-H2O systems with mole ratios; 5:1:13, 3:1:11, 5:1:14.39, and 3.75:1:12.25 at different setting ages by using the X-ray Diffraction and Differential Thermal Analysis (DAT) methods are studied. The same results are shown that the system with different mole ratios leads to different setting processes; the 5Mg(OH)2MgCl2 8H2O phase may be in either stable state or metastable state, it depends on the existance of gel phase or other phases in the system.
Abstract: A magic square of order n is a n×n matrix whose elements are positive integes of 1 to n2 and such that sum over each row, each column or each diagonal is equal to n (n*n + 1)/2. A kind of method of magic squares construction is considered. From auxilliary matrix by so called half turning. We can get a magic square of order n though at most 4 steps.
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
