Abstract: The quality of the billet is associated with the technology parameters of Continuous caster. Under conditions of actual technology operation of Continuous Caster in Han dan steelwork, the external and internal quality of a square billet, and the mechnical proprety of the rolling products has been investigated in order to be able to minimize various defects and improve its quality.
Abstract: The influence of Si and Mn on the toughening and embrittlening of Si-Mn-Mo-V steels in the quenched and low temperature tempered condition has been studied in this paper. Experimental results indicate that the segregation of P at austenite grain boundaries is seriously promoted by the Mn addition in-the steel without Si. The segregation of P may be occured during the austeni tizing and subsequent cooling by the co-segregation of Mn and P.The steel at quenched and low temperature tempered condition is offen failed by intergran ular fracture, with low impact toughness because of P segregation.The segregation of P and Mn at the austenite grain boundaries is significantly decreased by the addition of Si in the steel which has been embrittled by Mn (about 2%).Auger Spectromicroscope analyses show there is an obvious segregation of Si at the austenite grain boundaries of the Si bearing steels.It is well known that Si and P have a nagative interaction coefficient,sip<0.For this reason,P was repelled away from the austenite grain boundaries where si has been alread segregated and then the concentration of P at the grain boundaries is decreased.For reasons given above,the grain boundar ombrittlernent and in-tsrgranular fracture are suppressed and then the impact touphnese is markedly increased. The effects of si and Mn on low temperature tempered embrittlement(LT-TE), or 350℃-embrittlement as it called, of Si-Mn-Mo-V steels have been a-Iso studied in this work. Experimental results indicate that the LTTE is associated both with the impurities segregation at grain boundaries and with the transition of epsilon carbide to cementite which usually precipitated as thin film at the austenite grain boundaries. The segregation of impurities, especially P and the carnbide transition are both significantly influenced by si and Mn. Therefore, the temperature and the intensity of LTTE occured in these steels are also strongly influenced by si and Mn.
Abstract: The mathematical model of transversal mill modulus of the cold rolling four high mill is established by the program which the structure of model is determined on the principle of beam on elastic foundation, and the correcting factor of model is obtained by statistical analysin of experimental data. Thu. combined with the studying of hot roll camber, the equation of transversa sheet profile after rolling is proposed, which can reflect the physical rule correctly, is simple in construction with certain accuracy and is permitted online application in strip flatness control system
Abstract: Hot saw has been extensivelg used in metallurgical plant.The question of clearly knowing the real reason of sawtooth failure and increasing the service life of saw disc still merits attention at present.Based on the investigation of the condition of saws service at home, various types of saw disc failure are summa-rized in this artical. The typical stress and strain fields of sawtooth is computed with finite element method in elasticity and the results may provide mechanical basis for analysis of mechanisum of the sawtooth failure and design of reasonable tooth shape. In this paper, the compatation by finite element method in plasto-elast-icity is applied to determine proper force-energy parameter of saw.
Abstract: The Editorial program is one of the basic software package in a computer system The paper deals with the main idea and structure of the screen oriented (visual) display editor, for convenience called Y-edit, developed at software Development Center, Peking University of Iron and Steel Tech. Y-edit written in C language is highly portable, running under unix operating system.It works at all kinds of visual terminals,by utilizing virtual terminal.The grammer between the control commands and corresponding control keys is defined, providing the user with the facility to define his own control commands and the corresponding control keys. The responsive speed is elevated by the use of Gap working-area structure and simplified input control command.The success of Y-edit has provided ample experience in designing a system pratical program.
Abstract: To be restricted in resource of a microcomputer system,especially in storage capacity on secondary memories and computation speed of microcomputers, system efficiency on a microcomputer information retrieval system is usually very low. In this paper Some new methods using for increasing the system efficiency has been introduced, a special one is the technique called "strictly inverted sorting" about binary sorting trees.These methods has been used for "MCDS" successfully.
Abstract: The cadmium plated high-strength steel 35CrMnSiA was studied using modified WOL and cantilever beam specimens.The hydrogen content in cadmium coating was determined as well as the content in steel. The cadmium plating is enriched with hydrogen.The degassing at 200℃ through bright, nonporous coating is very slow.Hydrogen content in the steel increases first during baking and reaches its maximum at about 2-2.5 hours, then decreases slawly.The delayed fracture properties of the steel depend on its hydrogen content.When the hydrogen content in steel is at its maximum, the KIscc of the steel reaches its minimum and da/dt reachs its maximum.In order to improve the mechanical prorepties, its necessary to take a prolonged degassing baking treatment.
Abstract: The alternate-current work characteristic and the direct-current magnetization of the magneto-elastic transducer with the transformer steel have been studied experimentally.The study shows that the orientation angle of the sheet pattern of the transducer has significant influences on its work characteristic and that its work mechanism is principally the process that domain walls are shifted under the external stress.
Abstract: Two different kinds of interphase precipitation of carbides at isotherm al decomposition of 1Cr13 stainless steel, "interphase precipitation" and fibre ca rbide formation, were studied by thin foil TEM, and the relationship between them is also discussed in this paper. The retarding effect of interphase precipitation of carbides on crack propagation was verified by the SEM observation on fractography of impact specimens and relevant microstructure at declined, surface.Finally,this phenomenon was also confirmed by the observation on primary crack propagation and simultaniously was compared with the specimens after quenching and tempering.
Abstract: The black structure, non-martensite structure in carb o-nitriding case, is easy to occure in boron steel, when the heat treatment process is out of control, which reflects the decline of hardenability of case material.There are two kinds of black structure, surface black structure and transition region black structure, ed respectively by the inner-oxidati on of alloying eleasucments and the formation of carbide and nitride at the surfact, and by the redistribution and variation of occurence state of boron thought-out the case. In order to prevent the both black structures high carbonitriding temperature, later supply of ammonia, large amount of kerosene and smmall amount of ammonia supplied in carbontriding stage, and rapid quenching after the treatment are recommended.
Abstract: The RMS algorithm was initiated by K.S.Chandra and M.V.Rao in[1]. But in[1] the possiblity of degeneration was neglected.In our paper,we construct a counterexample showing that degeneration may infer the non-convergence of the algorithm and we make some corrections to the algorithm so that we can prove the convergence of the corrected 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
