Abstract: This paper discusses some geomechanics problems in block caving.In order to reduce the fluctuation of the RQD obtained in the same situ on a rock mass, a new NRQD（Normal Rock Quality Designation） is recommened, which is obtained by statistics of discontinuities carried out at the vertical direction to the main group of discontinuities.The statistics data on the discontinuities of a rock massare will not be in consistent with practical facts if the investigation is only carried out at horizontal level.The space investigation is recommended.A new supp-ositeion is presented that not only the size of rock and ore reduces,but their shap get more and more homogeneous in the course of caving and drawing as well.
Abstract: After analyzing the dynamic properties of vibrating drawing system, the loading capacity, unit energy comsumption and interfere strength of vibrated material have been put forwards as the indexes evaluating the loading effect of vibrating feeder.For both uniaxial and biaxial vibrating feeders, the optimization of operating parameters has been completed by means of the electronic computer.The results of our model tests show that the operating parameters optimized for the feeders and the formulas about them are dependable and easy to carry out.
Abstract: Based on the relation between the reaction rate and the residence time of the fluid in continuous reactor, a mathematical model is applied to simulate the Si-Nb selective oxidation of the Nb-bearing hot metal in continuous hot metal treatment process, predicting the behaviour of several components in metal and slag simultaneously and studying the effects of some important factors on the degree of the selective oxidation.The result of the calculation is in a good agreement with the experimental data.
Abstract: Late in 1960’s or early in 1970’s, Russian metallurgical workers started to investigate the electroslag melting of cast iron.It is obvious that the desul-furization, dephosphorization, inclusion removal and gas elimination of ESR or ESM have effects on making iron liquid purified and producing high quality casting.In particular, it would be possible to exert some electrochemical control either over the elimination of some harmful elements from the metal or over the pick-up of some alloying elements from the slag using do method. It is interesting that people attempt to make spheroidal-graphite cast iron directly by alloying and modifying under ESR or ESM condition without adding nodulizing agent. Althought the technological process of the ESR or ESM of cast iron is not perfect and some basic theories to accont for ESR or ESM applied to iron-melting are not yet satisfactory, the ESR br ESM of cast iron may well essentially improve the traditional process as a new technique for making high quality cast iron. This review collects the literatures and technological data on the ESR or ESM of cast iron in recent decaden and summarizes the researches and results on refining pig iron under ESR or ESM condition in foreign countries. onside-ring the natural resources and the characteristies of industrial development in our country, the suggestions that will develop the technological process and the theories of ESR or ESM for iron-metting are also presented.
Abstract: The effects of RE-complex modification on morphology of the carbide in-vanadium white iron was studied.After modification both the cubic-shape hyper eutectic Vc and strip-like eutectic Vc change into perfectly spheroidal carbide and the toughness and abrasion resistance of vanadium white iron is pronouncedly improved. The experimental results showed that to get spheroidal carbide a certain minimum content of vanadium in white iron is necessary.The sulphide and nitride with higher melting point formed during modification process are the substrate of heterogeneous nucleation of Vc and this is of great importance for carbide to grow in divorced eutectic.The desulphurizing and deoxidizing effects of rare earth elements raises the VC/melt interfacial tension and at the same time decreases the difference in the interfacial tension of advancing planes of different indices.Therefore the basal planes of growth pyramids advance at about equal speed, and finally the carbide grows as a spheroid.Furthermore,the higher interfacial tension makes the spheroidal surface of VC stable during growth process.
Abstract: The research and development of sheet metal forming is thought as a good way through which metallurgical industry will be developed to meet the needs of the revolution in material science and technology. Three stages of revolutionary developments in sheet metal forming industry have been differenciated. The mark of the first revolution is that sheet metal forming was operated with machines and dies in a factory instead of manual operation in a workshop) the second revolution is indicated by the assessment of process and formability derived from experiment,the study of theoritical formability and the foundation of cAE/FMS are the indications of the third revolutionary development in sheet metal forming. Since sheet metal forming, as a engineeing science, has got to marry sheet metal processing, a concept of SYSTEM ENGINEERING in sheet Metal （SESM） has been put forward,which covers: （a） sheet metal processing; （b） sheet metal forming;（c） coupling between metallugical processing（e.g. make-ing process, rollng process etc.） and forming process of metal. Computer-aided analysis of formability and computer-aided optimization and modelling of forming process are reviewed, and their schedules are illustrated. Furthermore, the comprehensive structure of sheet metal forming as a independent subject is presented.
Abstract: The existence of creep-corrosion interaction and the importance of investigation on it were demonstrated.The phenomena and mechanisms of environmental effect on creep deformation and creep fracture,and effect of stress and creep on corrosion were summarized and discussed.
Abstract: This paper systematically reviews the Landau theory and microscopic theory of incommensurate phase transitions and gives an outline of the methods of experimental researches on them.
Abstract: MgS and TiS2 were made at lab and the MgS-TiS2（2%） disks were sintered at high temperature. A sulfur sensor using the MgS-based solid electrolyte was prepared and the galvanic cell can be expressed by Mo |[S]Fe| MgS-TiS2（2%） |Mo, MoS2| Mo. The sulfur determination in liquid iron was carried out at 1375℃ without any protective atmosphere. The relation between the measured E and the chemical analysis [%S] can be shown as los[%S]=-0.3694-0.0077E（mV）（[%S], 0.003-0.134）. Also,the determination of the sulfur potential of the (u-Cu2S system shows that the partial electronic conduction parameter Pe’ is 6×10-4 Pa for the MgS-TiS2（2%） solid electrolyte at 1375℃.Pe’and fs were introduced for the correction of the E-[%S] relation.
Abstract: The resistance of 1 r13 stainless steel to crevice corrosion in 3.5% Nacl solution has been studied by the galvanostatic method, using acrevice assembly By analysis of the time dependence of potential, the rapid research on the initiation of crevice corrosion has been performed.The results indicate that the inhomogencity of the passive film and the conditions of solution within the crevice have a great effect on the initiation of crevice corrosion.
Abstract: The methods for the research on the electrochemical behaviors within stress corrosion cracks are reviewed, which consisted of pratical and modeled measurements and theoretical alalysis.Three important but unclear problems are also presented, these are processes of electrochemical kinetics at cracktips, the distributions of current and inpedence within cracks and the influence of polarization on the electrochemistry of crack tips.
Abstract: Stress Corrosion cracking （SCC） is the synergistic effect of applied stress and corrosion, and it widely occured in industries and engineering. Structure failure coursed by it is at least 15% per year. Among various relative factors, electrochemistry plays an important role, which is also a powerful tool in the researches of SCC processes. In this paper, a short review is given on this aspect.
Abstract: Stress Corrosion Cracking （SCC） is important in the corrosion problems, especially in industry and engineering, So more and more articles have been published in recent years concerning its possibie mechanisms, affecting factors,engineering failures and the methods to research. In this paper,a brief review is given mainly on the work of stress corrosion cracking in recent yeasr. Some researches on stainless steel and aluminium alloys are also induced.
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
