Abstract: By using the quantitative image analyzer, EPMA, SEM et al, the effects of the size, inter-distance, homogeneity and number of non-metallic inclusions mainly in Ca-S free cutting structure steel on tool life were studied.The results show that the critical length of non-metallic was 8 μm under this experimental conditions. A mathematical model describing the relation between the parameters of non-metallic inclusions and tool life was set up: T=α·Hβ·Neγ According to the model, the tool life(T) dePends mainly on effective number(Ne) and homogeneity(H) of non-metallic inclusions in steels.
Abstract: Using spheroidal graphite cast iron to produce the. casting which resistance to high-presure is an advanced technique. It is a key Problem of producing spheroidal graphite that feeding is difficult, especially Producing thin and complicated presufe-resisting casting causing sisPer-sed shrinkage at hot sPot,which result in the leakage of fluid infiltrates. To solve the problem, the exothermic riser for compensating volume contraction of spheroidal graphite cast iron can be used.The results show that the rate of heat dissipation through the exothermic riser decreases by about 53% as compared with sand head, the modulus of exthermic riser is twice as much as the geometric modulus, 50-80% of riser metal can be saved. The exthermic riser can solve the feeding problem above mentioned but the sand riser can't do so.
Abstract: The set uP of the continuous casting computer control system in the guarantee for continuous casting productive automation. In order to Improve and Perfect the function of this system, it is very important to analyse and study, using simulation method, the mathematic model of continuous casting solidified heat transfer Process by means of comPuter-aided-design. This Paper mainly introduces the set uP. of the mathematic model, the mathematic choice of simulation algorithm, the content of the computer simulation software package'and the analysis for its applicated results.
Abstract: The quantitative influence of interphase Precipitation on the Y.S. and ITT of steel are investigated in three Nb-V steels. The strengthening mechanism of interphase Precipitation is studied also.
Abstract: The microsegregation characteristic with which structure of rapidly solidified Powders of maraging steel is accompanied has been studied. The experimental results are as follows:with increasing cooling rates, segregation characteristic changed as the structure changed from dendritic→cellular-dendritic→cellular→pisolitic morphology. Microsegregation extent decreased obvious.It is found that nosegregation occurs when the microstructure is Pisolitic structure.
Abstract: White cast iron powder containing 2.875 Pct. C, l.3pct Cr was obtained by rapid solidification technology. The fully densified compact mat erial for testing has been prepared by the warm isostatic pressing (WIP) method at 720℃ for three hours with pressure of 150 MPa. The structure consisting of 1 to 3 μm in size ferrite grains and Cementite part-ides smaller than 3.5 in size was developed after WIP-uPsetting at 63 pct. strain. Superplastic behavior of the materials after WIP and WIP + upsetting were investigated in the temperature range 670-770℃ at strain rates from 3×10-4 to 1 s-1. At low stresses, the superplastic white cast iron exhibited a high strain rate sensitivity exponentm of 0.42 attemperature 720℃ arid ε=3.10-3~3.10-2S-1, it could develop a new proc eessing routes for new industrial applications.
Abstract: The effects of instability in repetitive signals acquired from rotatingmachines, can be critical in the extraction of Periodic signatures by cepstrum analysis for diagnostic applications. In this Paper, the rePetit-ive signal is decomposed into two components, i. e. waveform an'd rePeti-tive Pulse series. The effects of instability are represented by the levels of magnitude modulation, phase modulation, wave deformation and background noise. Based on the theory of deconvolution, a discussion on Perio dic signature analysis through cePstrum is Presented, which shows that Periodic signatures can be represented by the harmonics in cepstrum which only have relationship with the level of instability. This results can be very helpful for practical applications.
Abstract: A GTO cascade equipment of saving energy is a modem tyPe of rec-tifire equipment.The Power factor of this equipment is improved greatly. The application of this system will have more important significance for economy of energy. In this Paper the principles and methods of improv-ing the power factor are discussed. Performance curves of the power fac for of a wound-rotor induction motor, a SCR cascade and a GTO cascade equipment are shown also. These Curves are drown from a experime-ntal equipment developed, by us. The comparison between these curves can be used to explain the advantage of the high power factor of a GTO cascade equipment.
Abstract: This paper develoPs the concepts of a pair of trees and their distance in a linear graph. The necessary and sufficient conditions for a maximally and minimally di'stant tree pair and the algorithms for finding a maximally and minimally distant tree pair are given. This paper also disccuses the applications of maximally and minimally distant tree pairs in equal parameter graphs in the electrical network analysis, and Presents the dual algorithm of Principal partition algithm 1 and the algrithm of oPtimal harmonious decomposition of electrical networks.
Abstract: A start-tyPe flying shear controlled by the micro-computer control system can complete the works of cut head and tail, cut-to-length and cut-to-average length for high speed continuous hot rod mill.Based on the Principle, it can descride the shearing errors and the method of improving accuracy.The hardware figures and softwares block diagrams of the system are Presented in this Paper. It has been proved by the industrial scale experiment that the shearing eorror was decreased greatly.
Abstract: Caβ"-Al2O3 is a fast ion conductor of divalent cation conducting. It can be used to determine the activity of CaO in slag directly and be made a probe for determining the low oxygen in iron. The fabrication of Polycrystalline Caβ"-Al2O3 ceramic tube by slip casting are introduced and the effect of medium,Powder size and temperature on the quality of the tube are described too. For the slip casting, methanolic slips and powder molds were used. The high density (97% theoretical density) and heavy textured fired tubes were obtained after sintering for 2 hours at 1670℃. For checking the electrochemical properties of Caβ"-Al2O3 a Galvanic cell to determine the high temperature thermodynamic properties of the. La-O-F system was constructed in this work. The activities of calcia in. Caβ"-Al2O3 at 1113-1333 K were measured by the following cell Pt|CeO2 (s), CeF3 (s),CaF2 (s), CaO (β") CSZ|O2 (air)|Pt.
Abstract: The dissolved rare earth content in iron was determined by means of electrolysis of the sample in the organic electrolyte at low temPera-ture and radioassay technique. The oxygen activity in the molten iron was measured by solid electrolyte sensors made of ZrO2 (MgO) tube. The dissolved sulphur content was determined by aid of H2S evolution method. The relationship between the Y-O equilibrium constant in molten iron and temPerature at 1560-1600℃ and the Y-S equilibrium constant in molten iron at 1600℃ were determined. The interaction coefficients of eOY, eSY and other thermodynamic data were also determin-ed.
Abstract: The equation between the melting temperature of the material andits high-dispersity are deduced by means of thermodynamic method. The results are suitable for the particles which are circular or non-cir cular. These equations describe quantitatively the fact that the melting emperature of material is lowered with the increaes of its dispersity.d The result of calculation for pb is more agreeable to the experimental tata, obtained by Coombes, than the theoretical data obtained by M. Hasegawa et al.
Abstract: In this paper the law is proved that the symbol of the mixing enthalpy △${\rm{H}}\frac{{\rm{E}}}{{{\rm{mix}}}}$ is the same as that of the mixing extra-enthropy △${\rm{S}}\frac{{\rm{E}}}{{{\rm{mix}}}}$ in the atom state solution systems, based on the theory of the formation of solution and a lot of experimental facts. A means that criticize the reliability of experimental data, △${\rm{S}}\frac{{\rm{E}}}{{{\rm{mix}}}}$, △${\rm{G}}\frac{{\rm{E}}}{{{\rm{mix}}}}$ and △${\rm{H}}\frac{{\rm{E}}}{{{\rm{mix}}}}$ is obtained.
Abstract: The process of crevice corrosion of 1Cr13 stainless steel in neutral 3.5% NaCl solution has been studied by the AC impedance measurement technique. A special impedance measurement device was designal for this purpose.Through the imPedenCe measurement in situ of corrosion process, we have gained a new insight into the state of the samples interface within the crevice such as the adsorptional effect of the chloride ions etc.From the results,an anodic dissoluson equation was given as follows: Me2++mH2O+nCl-→MeCln (OH)m+mH+.
Abstract: A Process for preparing industrial grade manganese carbonate frommanganese mud-a waste from potassium permanganate factory-ispresented. The process comprises three steps:(1) Reducing and leaching the manganese mud with waste pickle liquor as well as precipitating iron, (2) Purification of Pregnant solution, (3) Precipitating manganese carbonate by adding ammonium bicarbonate. In the first step, if the ratio[H+]/(Fe++] in pickle liquor is welladjusted, the leaching of manganese and precipitation of iron may be proceed simultaneously so that the ammount of alkaline used in precipitating iron can be reduced greatly. Na2S is added to remove other heavy metals.Ammonium bicarbonate is used for producing manganese carbonate in order to avoid the contamination byCa++ ion from the water. The pollution of the waste in this process is rather less than that of the pickle liquor and. manganese mud.
Abstract: Integral inequality involving Stieltjes integral in two independent variables is obtained in this paper. It is a generalization of integral inequality of Gollwitzer tyPe in two independent variables.
Abstract: In this paper, both symmetrical press and press-shear deformation are analyzed by means of rigid plastic finite element method. The calculation results are in good agreement with experiments It shows that the press-shear deformation can lower the normal pressure on the die-specimen interface and rnake the inside deformation more homogen eous.
Abstract: Five kinds of specimens of the Pure iron containing phosphorus were used in this work. After having removed carbon and nitrogen, we measured internal friction of these specimens at a temperature range from 300℃ to 800℃ with the inverted torsion Pendulum at low freguency·Consqu ently five specimens containing phosphorus contents at a range from 0.007 wt% to 0.28wt% show two internal friction peaks at about 580℃ and about 470℃ respectively. The activation energy of this peak at about 580℃ is 2.13ev, the another is 1·80ev. After quenching at high temPeratur e, two Peaks disappeared. Based on the results mentioned above, the Peak at about 580℃ is likely the Fe-P Peak (SS Peak) and the another is Probably the Pure iron Peak (PMPeak). Finally, the specimen of Fe-Ce-P alloy containing a small amount of rare earth element Ce was made a experiment. Three Peaks were found at about 703℃, 601℃ and 500℃ respectively. We have a tentative idea that these three peaks are the Fe-Ce SS peak, the Fe-P SS peak and the Pure iron peak (PM peak) respectively. It is remarkable that the PM peak temperature in the Fe-Ce-P alloy is higher than that one in the Fe-P alloy. The work, which a small amount rare earth element affects the internal friction of Fe-P alloys, is being perfected.
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
