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Procofev Vladimir
Faculty:Phisicimetallurgy
Speciality:Metallurgy of ferrous metals
Specialization: electrometallurgy and production of ferro-alloies.
Leader of work: doc Dumnich Anatoliy Haritonovich
Theme of master's work:: Research of thermal work of lining of ladles
Master's work
Thermal losses of metal in a ladle.
Mathematically is represented and numerically problem of a variable thermal conduction in lining of a ladle for want of availability in it(him) of metal is decided(solved). The quantitative influence of parameters to decrease(reduction) of temperature of metal in a ladle is remarked.
Temperature of metal on issue from the converter is the important parameter influencing to technological and economic parameters melt. For want of to high temperature of the issue is essentially increased oxidabilityof metal and slag, that entails decrease(reduction) of stability(resistance) of lining of the converter, increase of an intoxication of iron and alloying. In a consequence the quality of metal is worsened at the expense of the increased contents of gases and unmetal inclusions.
The main articles of losses of heat by metal in the indicated period are:
- Heat radiation of a surface of a jet of metal for want of it issue from the converter in a ladle;
- Thermal losses by a radiation from a mirror of metal in a ladle;
- Loss of heat through lining of a ladle;
The losses of heat through lining include warmly of heat of lining and òåïëîîòäà÷ó from a surface of a casing(cover) in an environment.
However, till now there are no datas on an evaluation of influence each from these sources on general(common) losses of metal from the issue up to an extremity having pour..
In the given work the attempt by a theoretical way with use of experimental data was undertaken to evaluate losses of heat by metal through lining on an example of 350 tons of a ladle used at factory "Àzovsteel" in converter workshop.
The transfer of heat through lining of a ladle should be considered as non-stationary process of a thermal conduction through two stratums with various physical properties. Therefore this process can be described by a system of differential partial equations.
For a solution of the delivered problem it is necessary to accept boundary conditions. For want of choice of boundary conditions it is necessary to emanate from the following:
· Non-stationary thermal conductivity in lining it is necessary to consider as periodic process;
· Temperature of metal after the issue from the converter continuously is changed;
· Before submission of a new ladle on having pour. it(he) passes operation baking and reference temperature is changed;
· The losses of heat from a surface of a casing(cover) are value a variable.
In various points of lining the thermocouples with the help of which were built the temperature fields in different instants were determined.
The distribution of temperature in a working stratum satisfactorily is described empirically by the equation of a kind:
For want of it the coefficient of correlation makes To = 1,0.
For of a reinforcing stratum the temperature field is described by the equation:
With allowance for of time the equation aproccimation in the equation
oc
The thermal cycle of work of a ladle consists of two periods:
· Heat of lining in time stay of metal in a ladle;
· Cooling of lining between having pour..
For period of cooling of a ladle the entry conditions is the distribution of temperature in the worker and reinforce stratums obtained in an extremity of period of heat.
The experience with use of the following physical datas were conducted:
· Temperature of metal on issue from the converter (1650 oc)
· Time of a determination of metal in a ladle (9720 ñ)
· Thickness of stratums of lining (0,2ì; 0,1ì)
· Volume of a working stratum of lining (23,78 ì3)
From the analysis of outcomes of account of temperature fields it is possible to tell the following:
· With magnification of number pouring in of a ladle temperature in lining will increase till 10-15 pouring in is not then changed;
· Hardly temperature varies on depth (0,05-0,08) ì
With use of datas of distribution of temperature in lining the accounts of an amount of heat were executed which is accumulated by(with) lining during stay of metal in a ladle. It has allowed to evaluate decrease(reduction) of temperature of metal in an outcome absorption of heat by lining of a ladle.
The sharp decrease(reduction) of temperature of metal is observed in the beginning of operation ñòàëåðàçëèâî÷íîãî of a ladle (10-15 pouring in).
Conclusions
· For decrease(reduction) of temperature of metal on issue from an aggregate it is necessary to increase frequency of use of a ladle. It is necessary to reduce an amount of ladles simultaneously were in work.
· For not the derivings " of cold metal " before having pour. should be increased it temperature and to use "young" ladles.
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