SU1284654A1 - Method and apparatus for automatic control of process of continuous metal-casting - Google Patents

Abstract

The invention relates to continuous casting of metals. The purpose of the invention is to increase productivity and increase yield. During the casting process, sensors 1 measure the temperature of the working walls of the mold. The signals from the sensors 1 are fed to the inputs of the algebraic adder 2, the signal from the output of which is equal to the half-sum of the input signals is compared with the signal of the setpoint 3 on the algebraic adder 4. When the temperature of the walls drops below a predetermined level, the metal level in the crystallizer is increased, and when it is increased, it is lowered with help In the actuator 6, the position of the stopper. 2 sp.f-ly, 1 ill.

Description

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The invention relates to metallurgy, namely to continuous casting of metals.

The aim of the invention is to improve the performance of the metal casting and increase the yield.

The drawing shows a diagram of an apparatus for implementing the method.

The device contains sensors 1 of the temperature of the working walls, the first algebraically-10 admissible. Increasing the temperature adder 2, setting unit 3 temperature rounds of the copper walls of the mold in the zone

ry working walls, the second algebraic adder 4, power amplifier 5, the actuator 6, which regulates the flow of metal from the bucket.

As sensors of temperature, a 3: 1 leads to the formation of spider-walls of the mold on the ingot can be surface cracks, reduce the use of chrome-coel thermocouples embedded in the wall, reducing the temperature of the algebraic adders and the power amplifier — 20, the introduction of copper particles with the size of a conventional device of the same functional — 12–19 µm into the surface of a continuous

from the AKESR instrument complex. As an executive measure below the set point, the metal level rises again.

Studies have shown that during continuous casting, the highest density of heat flow through the walls of the mold is observed on the horizon 5-15 mm below the metal meniscus. At this level, the working wall temperature reaches maximum values and, under certain casting conditions, it exceeds the liquid metal flow rate higher than 210-230 ° C under conditions of increasing pull force of the ingot from the mold over 3.5-10.5 tons for ingots with an aspect ratio of more than

quality and yield of the metal. The reason for the formation of these cracks is the splicing in the meniscus zone as a result of increased diffusion, heated over 210-230 ° C of copper in these conditions. At the same time, the technological allowable coefficient of friction between the ingot and the copper walls of the mold, 0.47-0.55, increases, for example, for an ingot 280X 1650 mm to 0.62-7, while maintaining the operating speed of 0.8-0.9 m / Min

A servomotor associated with the stopper of the intermediate bucket can be used.

The device works as follows.

Temperature sensors 1 produce signals that are summed in the first algebraic adder 2. A signal from its output equal to the sum of the input signals, comparing with the signal of the setpoint generator 3 of the working wall, passes to the output of the second algebraic adder 4. The difference signal is amplified in the power amplifier 5 and arrives at the actuator 6, controlling the regulating stopper.

Example. On a curved continuous casting machine, steel 2SP is poured into a 1200 mm long copper mold with a section of 1550 × 250 mm at a drawing speed of 0.8 m / min.

The temperature sensors, which are copper-constantan thermocouples, the copper electrode being the working wall, are installed at a depth of 5 mm from the wall surface facing the extruded ingot, at a level of 0.1 m from the upper increase in its flow rate from the ladle. Maxi edge of the mold. At some moment of the heat sink, again you can avoid overheating of the working walls in the meniscus area by changing the metal level, controlling the temperature of the working walls and comparing it with the specified value. When the temperature of the walls of a given value is exceeded, the metal level should be lowered, reducing its consumption from the ladle and, thus, contacting the melt with the overheated surface of the working wall. The heat sink maximum then moves below where the temperature of the walls begins to rise. At the same time, the temperature of the walls above the new metal level rapidly decreases due to the coolant. As soon as the wall temperature drops below a predetermined value, the metal level should be raised by

 as permissible. Increasing the temperature of the copper walls of the mold in the zone

its lower than the specified value, the metal level rises again.

Studies have shown that during continuous casting, the highest density of heat flow through the walls of the mold is observed on the horizon 5-15 mm below the metal meniscus. At this level, the temperature of the working wall reaches maximum values and, under certain casting conditions, it exceeds the maximum permissible value. Increasing the temperature of the copper walls of the mold in the zone

 3: 1 leads to the formation of spider-like surface cracks on the ingot, reducing the liquid metal above 210-230 ° C under conditions of increasing efforts to extract the ingot from the crystallizer over 3.5-10.5 t for ingots with an aspect ratio of more

 The introduction of 12–19 µm particles of copper into the surface of a continuous

quality and yield of the metal. The cause of these cracks is

increase its consumption from the bucket. The maximum heat dissipation at the same time again remixing in the meniscus zone as a result of increased diffusion heated over 210-230 ° C of copper in these conditions. At the same time, the technological allowable coefficient of friction between the ingot and the copper walls of the mold, 0.47-0.55, increases, for example, for an ingot 280X 1650 mm to 0.62-7, while maintaining the operating speed of 0.8-0.9 m / Min

Overheating of working walls in the area of the meniscus can be avoided by changing the level of the metal, controlling the temperature of the working walls and comparing it with a predetermined value. When the temperature of the walls of a given value is exceeded, the metal level should be lowered, reducing its consumption from the ladle and, thus, contacting the melt with the overheated surface of the working wall. The heat sink maximum then moves below where the temperature of the walls begins to rise. At the same time, the temperature of the walls above the new metal level rapidly decreases due to the coolant. As soon as the wall temperature drops below a predetermined value, the metal level should be raised by

time, the temperature of the walls at the place of installation of thermocouples exceeds 180 ° C. The temperature of the working surface of the wall reaches 200 ° C. A further increase in the wall surface temperature is unacceptable. The signal from the temperature sensors, passing through the blocks of the device, causes a decrease in the level of the metal in the mold by reducing its flow from the ladle. As the metal meniscus drops below the thermocouple level, the wall temperature at this level decreases. While decreasing

extends toward the upper edge of the mold. The temperature of the walls that have cooled down in a step of lowering the level begins to rise again. The frequency of level fluctuations in this case is 0.001-0.01 Hz, and the amplitude is 0.05-0.3 m.

The technical advantage of the invention lies in the possibility of stabilizing the heat transfer rate in the mold at a given level without reducing the casting speed, which allows increasing the casting performance of the metal and increasing the yield.

Claims (2)

Invention Formula . The method of automatic control of the process of continuous casting of the metal, including the regulation of the level of the metal in the mold by varying its flow rate from the ladle, characterized in that, in order to increase the performance of the metal casting and increase the yield of the suitable metal, the temperature of the working walls of the crystallizer is measured at a distance equal to 0.5-0.2 of the height of the working walls below the upper edge of the mold, at a depth equal to O-0.15 of the thickness of the working wall from the surface facing the extruded ingot, compare it with a given, and with a decrease in the temperature of the walls below a given one, the level of the metal in the mold is increased, and with an increase, it is lowered until the temperature of the working walls of the crystallizer is set to a given value. 2. Device for automatic control of the process of continuous casting of metal, containing temperature sensors of the working walls of the mold, temperature setter, two algebraic adders, the outputs of temperature sensors connected to the inputs of the first algebraic adder, the output of which is connected to the input of the algebraic adder, the second input of which is connected to the output of the setter temperature, characterized in that, in order to improve the performance of the metal casting and increase the yield, it is equipped with the power unit and the actuator position of the stopper in the bucket, with the input of the power amplifier connected to the output of the second algebraic adder, and the output to the input of the actuator.