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| Research of process of cooling and crystallization of cast-iron grinding bodies of ellipsoid form on a konveyerno-kokilnoy machine |
Development of the guided process of crystallization of grinding bodies
Grinding bodies are the basic type of materials, which are used for growing of iron-stone and ores of the coloured metals,
cement clinker shallow, uglya, build materials.The stake of grinding bodies from total expenses on growing of raw material
shallow arrives at 30%.
At the Makeevskom casting plant are developed and made the cast-iron grinding bodies of ellipsoid form. The grinding
bodies of ellipsoid form provide more effective process of growing of raw material shallow, conditioned by the greater
total area of surface of ellipsoids on comparison with balls at the same mass, possess promoted wearproof related to more
high by a volume hardness of cast-iron grinding bodies, allow to lower the expense of grinding bodies on the ton of the
ground down material and lower expenditures at making.
One of lacks of opened kokiley is the rapid cooling of metal in overhead part of founding due to the radiation of heat
in surrounding one space. On the assignment clauses of heat intensity of cooling of the opened mirror of liquid metal is
proportional to the fourth degree of temperature, and intensity of taking of heat by heat conductivity from founding to
kokilyu is proportional to the first degree of temperature of metal. A wide difference in speeds of cooling results in
a volume, that a hard crust appears on the surface of mirror of metal, while central part of founding remains liquid.
It results in considerable difficulty of taking
of gases from the liquid of the good poured off in an atmosphere and is instrumental in formation of gas shells and usadochnoy
friability into founding.
With the purpose of improvement of terms of gazovideleniya from a liquid metal in the process of crystallization a new
structural element is offered – mirror reflector which provides the management by the process of consolidation and crystallization
of founding in kokile, that results in the rise of their eksplutatsionnih descriptions. Mirror reflector of semicylindrical
form with a well reflecting internal surface.
At passing of kokiley speed of cooling of the opened surface of liquid metal being found in the cells of kokilya due to
the reflection of thermal stream from the concave mirror surface of reflector back onto all overhead part of opened kokilya
with located in him cells with a liquid metal diminishes under a mirror reflector. The increase of duration of stay of
mirror of metal in the liquid state is instrumental in more complete deleting of gases from all volume of metal and removal
of defect of foundation of founding.
For determination of optimum sizes of mirror reflector computations of speed of consolidation of grinding bodies during setting
of mirror reflector above locomotive kokilyami on leaving on a horizontal area with the use of mathematical model of process
of crystallization were produced. Computations were executed for the grinding body of the type T9 with the diameter of foundation
60 mm at the initial temperature of the inundated cast-iron 14000C .The best results are got at length of mirror reflector of making 0,20-0,25 lengths of horizontal part of conveyer. The place
of setting of reflector on length of horizontal area of conveyer relies on the temperature of the inundated cast-iron. In
production terms the temperature of cast-iron before the inundation in kokil can change from 1320 to 14000C. As computations show, on the developed mathematical model at the minimum temperature of cast-iron a reflector must be found
near a zalivochnoy bowl, and at a maximal temperature – in the distance from a zalivochnoy bowl, making 2/3 lengths of conveyer.In practice the management by position of reflector will be automated on a signal from the sensor of temperature
of cast-iron.
Application on the operating konveyerno-kokilnoy machine of the guided process of crystallization of cast-iron grinding bodies
with the use of mobile reflector (thermostat) will allow to lower the internal defects of the cast-iron founding and povisit
their operating properties, such as udarostoykost and wearproof.
V.L. Gyk, S.I. Ginkul, A.I.Tuyahov, A.V.Melnik, A.I. Yarmolenko, A.V.Nepochaev
The mathematical model of crystallization of cast-iron grinding bodies of ellipsoid form is developed taking into account temperature expansion in the system “metalloforma-grinding body”. Computations of dynamics of consolidation of cast-iron in the cell of metalloformi grinding body are executed. The developed mathematical model can be used for the improvement of technological process at production of grinding bodies on konveyerno-kokilniy machines.
V.Ŕ. Ignatov, A.A. Pahomov, A.A. Trojan, V.L. Gyk, A.I. Tuyahov, A.I. Yarmolenko
The results of researches of application of cast-iron grinding bodies of the improved form as ellipses which are used in mining industry for crushing of gelezorudnih materials are expounded. Their advantages are shown on comparison with katannimi and the poured balls at cost making and efficiency of crushing of materials at identical external environments on the operating equipment.
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