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Магистр ДонНТУ Овдиенко Александр Александрович

Ovdienko Alexandr Alexandrovich

Fiziko-metallurgical faculty

Chair of technical thermophysics

The Speciality: Industrial the heating engineer

The Theme of final work:

Research processes exchange of heat and weightout of furnac decontaminations steel in an electrostatic field

The Supervisor of studies:Zaharov Nikolai Ivanovich


Materials on the theme of master's work: Biography | Abstract | Library |

Research processes exchange of heat and weightout of furnac decontaminations steel in an electrostatic field


Introduction

In all industrially developed countries metallurgy is considered one of the major branches of economy. For last 50 years steel world production has increased from 200 million т. To 800 million т. Thus, the most essential changes have occurred in qualitative perfection of metal products. It became possible thanks to introduction of progressive technologies for savings of energy and resources, especially out of furnace metal processings. According to the National Program of development ГМК of Ukraine, out of furnace processing of metal and ladles metallurgy as a whole should become the major link of metallurgical technologies since quality of metal products which they raise, is one of major factors in a competition of the free market. It is characteristic, that consumers of metal and its production in the Far abroad pay extra for the metal processed out of furnace in the ways. It is no wonder therefore, that the overwhelming part of metal of these countries is exposed out of furnace to processing, expenses on which immeasurably below cost metal in ingots.

A theme Urgency

Ukraine is included into ten the largest manufacturers and exporters of a steel. At the same time profitability of the Ukrainian steel is known, and its export goes under the low world prices owing to the lowered level of properties necessary for metal. Therefore for Ukraine wide application combined processes for savings of energy and resources steel out of furnace decontaminations is actual.

The Purpose and work problems

Modelling difusion decontamination process on ПЭВМ and research processes exchange of heat and weight.

Practical value of results of work

To receive mathematical model of decontamination and graphic dependences processes exchange of heat and weight from decontamination time.

The Cores a part

The problem the steel decontaminations, connected with increase of its quality, for today remains actual. There is a perspectivity of use of an electrostatic field for carrying over of ions of deleted gas from steels in vacuum. It is known, that forces of interaction of these ions with a metal surface can be considerable. At the same time, association of ions in neutral molecules facilitates them десорбцию in vacuum space as the forces responsible for communication of neutral molecules with a mirror of metal (force В-Д-Ваальса), are rather insignificant. Some variants of use of vacuum with an electrostatic field in technology decontaminations from the hydrogen dissolved in it and nitrogen became possible. In the first of them are created intensity of this field, exceeding critical value Eкр at which on a mirror of metal by means of a considered field energy which exceeds energy of communication of ions with metal is informed positive ions of deleted gas. Occur failure of particles from interphase border motionless and an intensification of process of decontamination. It occurs at pressure 5-30 кВ at size of an interelectrode interval 1,7 Size Екр see, as is known, depends on a blanket structure, and also from character of interpartial communications. In the second variant in which at decontamination from hydrogen раскисленной steels portions pumping out the electric potential of a negative sign moved on an electrode of heating of the vacuum-chamber. Small intensity of an electrostatic field was led by intensifications of process of decontamination. At the same time, the electric current of hydrogen issue proceeding in a cavity вакууматора, is the indicator of relative completeness of process of decontamination. In this case refusal of the further continuation of this process after achievement in size of a current of certain small value (in comparison with its initial size) saves power resources. And, at last, the third possible variant of use of an electrostatic field at steel pumping out in a ladle considers the known fact of transition diffuzionno-adsorbtsionnogo limitations of process of decontamination of metal in kinetic on reaching some concentration of deleted gas in расплаве. Thus, if decontamination from the dissolved nitrogen which atoms experience known power difficulties of association in molecules on interphase border small enough concentration of these atoms on border "vacuum-metal" can complicate decontamination process is made. For an intensification at this stage connection of a source of a moderate electrostatic field of negative potential and corresponding intensity is perspective. The source should be localised in the vacuum-chamber. The external field redistributes ions of deleted nitrogen on a metal mirror, forming areas of clots of ions. Thanks to presence of clots of ions their probability in clots and the generated molecules in a cavity vakuumeishon increases. Thus process decontamination of steels can be is intensified. At the first stage of researches as theoretical study of a question the mathematical model difushion process in motionless steels is constructed at influence on it of vacuum with an electrostatic field on a way of pumping out in a ladle: