Methods are proposed for intensifying mass transfer in blow of steel in a ladle using acoustic vibrations. Industrial tests of blowing metal in a ladle using a lance and imposition of acoustic vibrations generated by an external acoustic radiator are described. An acoustic blow plug (ABP) containing a resonator of jet-acoustic vibrations is proposed for argon blow of steel in the ladle. Model studies and theoretical estimates of factors that contribute to intensification of mixing and decrease in the blow plug erosion are described. The results of industrial testing of blowing steel in a furnace-ladle plant using the ABP at the Severskii Pipe Works are presented.
Methods and devices that produce effective actions on different objects in the course of steel production through the use of acoustic and pulsating vibrations are considered. Data on the results of the use of blowing tuyeres, devices for cleaning blowing tuyeres, a method of generating structuro-acoustic effects in the furnace workspace, and a device for acoustic blasting of the lens of radiation pyrometers are presented.The need to increase the quality of steel has grown substantially in recent years. Ladle furnaces, vacuum furnaces, and other devices that involve argon blow of metal or blow with alternative gases have been used. Nevertheless, the studies related to learning how to increase the service life of blowdown devices and increase blow efficiency require further work. Of no little importance are questions related to dust extraction in performing this process. From this standpoint it is of interest to review the work of OAO Severskii Pipe Factory gained in joint studies with GOUVPO Ural State Technical University -UPI and OAO Dinur on the development and practical application of acoustic and pulsating devices in the production of steel. In particular, the following methods and devices have either undergone pilot-plant tests or have been in long-term use:-ladle treatment of steel with an inert gas with the use of acoustic vibrations; -application of pulsating vibrations of an argon blast ("pulsars") in blowing of metal; -a device for use in cleaning the blowing tuyeres of steel-teeming ladles;-the use of an acoustic blast method of dust precipitation in casting furnaces;-the use of acoustic vibrations to protect the lens of radiation pyrometers against becoming clogged with dust.Note that a number of other methods and devices that employ acoustic and pulsating vibrations are also at the developmental stage. LADLE TREATMENT OF STEEL WITH AN INERT GAS USING ACOUSTIC VIBRATIONSExperience gained by the OAO Severskii Pipe Factory in argon blow of steel has been previously described in detail in a number of studies [1 -9]. It was noted that a comparative analysis of the data of pilot-plant tests and trial smelting by acoustic blow has demonstrated that in terms of a number of indicators, including the number of inner and outer skins on the tubes, level of contamination of the metal with nonmetallic inclusions as well as ordinary and corrosive-active inclusions, and the content of nitrogen in the metal, trial smelting and ordinary smelting yielded roughly identical results. The content of the ordinary type of nonmetallic inclusions and of corrosion-active nonmetallic inclusions in both the trial and ordinary ladles satisfied the technological conditions. The content of oxygen in the metal in ordinary blow amounted to 9 ppm and in acoustic blow, 6.4 ppm, i.e., it fell by 28.8% in acoustic blow. The specific consumption of argon decreased slightly in acoustic blow, while the specific consumption of electiricty was reduced by 7.5%. It was also noted that after 40 smelting events with ordinary blow, the height of th...
This article presents the results of the study of the effect of annealing on the sheet resistivity and temperature coefficient of resistance (TCR) of resistive films obtained from targets of the Cr–Ni–Si system using magnetron sputtering. A diagram of the composition–sheet resistivity of the Cr–Ni–Si system films with a thickness of 100 nm is proposed. It was established that resistive films of the Cr–Ni–Si system deposited by magnetron sputtering on silicon semiconductor plates with a SiO2 sublayer with a thickness of 100 nm, have sheet resistivity up to 350 Ω/square. It is shown that it is necessary to determine their eutectic compositions for the manufacture of targets by casting. Calculations were carried out and it was established that eutectics of the Cr–Ni–Si system contain 36.4 and 38.5 at.% Ni, which is 4 to 6 times higher than in the PC series alloys of this system. Due to the high content of Ni sheet resistivity films of eutectic compositions with a thickness of 100 nm is in the range from 100 to 200 Ω/square. It was noted that it is necessary to develop new four-five-component alloys based on the Cr–Ni–Si system with the introduction of refractory (Mo, Nb) and rare-earth (La, Y) elements into it, in order to increase the sheet resistivity of films and to decrease the melting temperature of alloys.
Residual stress distribution in multilayer semiconductor structure is complicated and has a significant impact on device characteristics and yield, therefore their study is one of the actual tasks of modern device engineering. Purpose of the present work was to develop methods of estimation of actual residual stress distribution at the whole area of semiconductor structure and its elements as well.The estimation of residual stress distribution at the area of semiconductor structure was carried out on the basis of determining of local deformation of some areas of the structure by Makyoh topography. This method is based on consequent measurements of intensity of Makyoh image elements of the structure along the chosen direction followed by calculation of micro-geometrical profile and curvature radius.The estimation of residual stress of topological elements Si–SiO system was carried out by means of calculation of interference pictures obtained in a film-substrate gap after separating of film edge from substrate along open window perimeter.Analytical expressions relating semiconductor structure image characteristics with their deformation were developed by means of finite elements method. The expressions allow determining of local residual stress of chosen area of the structure. The examples of stress calculations in real structures are given.Proposed residual stress calculation methods allow to take into consideration character and curvature form of substrate, and also to estimate their magnitude in real topological elements of semiconductor circuits.
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