DE2363451A1 - Adding aluminium to the mould in continuous casting of steel - using tachometer on guide rolls to control aluminium addn. - Google Patents

Abstract

The device is for feeding an addn. into a metal being cast, and esp. for the feeding of wire or strip into the mould on a continuous casting machine, where the wire is fed from a coil using a switchable, continuously adjustable, motor-driven and thyristor-controlled wire feeder. The novelty is that a controller is used for the automatic adjustment of the wire feed rate in accordance with the casting speed. A tachometer is pref. mounted on the slab guide rolls of measuring the casting speed and supplying a voltage to the controller for regulating the wire feeder. Three potentiometers are included in the thyristor control circuit, a fourth potentiometer being used for hand operation of the controller. Used for adding aluminium to the mould for killing the steel being cast, e.g. into a slab. A consistent percentage of Al can be added at all times.

Description

Gerhard Kroger welding technology

Device for feeding an additional material to a base material in the casting process

The invention relates to a device for feeding a Additional material to a base material in the casting process, in particular in continuous casting by means of a permanent mold and one Continuous casting machine j wherein the additional material is preferably used when the base material is poured into the mold in the form of wire or Strip material is cast from a reel through a switchable and continuously adjustable, motor-driven and Thyristor controllable wire feed gear is fed in front of the mold.

When casting. In particular cast steel, the liquid base material in a. Manifold filled. Openings are provided in the bottom of the distributor, the tandish. Any of these Openings are arranged above a mold into which the casting flows. The bottom of the mold can be opened locked. When casting on, the water-cooled mold is included. filled with the material to be potted and, after a certain filling level has been reached on its underside open in full cross-section. The opening takes place by that the stopper closing the opening, which is usually attached to a chain, is pulled out of the opening. The casting that has now become doughy in the lower part of the mold, that has connected to the stopper becomes the Chill pulled. By continuously pouring on the filling side and conveying the on the underside accordingly

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the strand emerging from the mold in the first phase by means of the chain driven by the continuous casting machine and subsequently by the also driven by the continuous casting machine Slab conveyor rollers and the dead weight of the strand a continuously running continuous casting is achieved, the casting being correspondingly cooled in the mold.

It is known here. " to be located at the continuous casting machine a speedometer _t indicating the running speed of strand and the casting speed electrically by changing voltage. In the usual designs of the continuous casting plants, the cross-section of the mold is given, so that the volume of the casting can be calculated arithmetically when the casting speed is displayed and is specified in a diagram. The maximum achievable casting speed corresponds to the maximum tachometer voltage. When casting steel, the steel must now be calmed by adding aluminum. Here it is already known to feed the additive material to the liquid steel in the ladle. In this case, the proportion of the additional material supplied can be determined proportionally precisely, but the output of the additional material is low and hardly controllable, since the additional material floats in the casting.

When the casting material is poured into the mold, a very strong turbulence in the casting, which can be used advantageously for alloying. It is now known for Calming the cast aluminum in wire form the cast when pouring to move into the mold. The wire feed takes place via an adjustable gear, whereby to determine the alloy content, the wire feed speed set by hand can be. The disadvantage of this design is. the manually adjustable feed speed of the additional material terials, since the amount of aluminum supplied must be dosed in exact percentages. and this with a manually

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operable gear shift due to the different flow speed of the casting is not possible. Although this method brings a very high output of the additional material, however, different steel grades are produced.

The object of the invention is now to provide a device to find the casting continuously when pouring into the mold depending on the amount of steel flowing through, supplies the required aluminum proportion for calming.

This object "is achieved according to the invention with a device. of the type mentioned at the outset, in that the gear unit unwinding the wire from a reel is preceded by a control device which automatically regulates the wire feed speed as a function of the casting speed

For this purpose - according to the described embodiment of the invention, the strand exiting at the axis of the mold conveying slab conveyor rollers driven by the continuous casting machine licked speedometer machine is used, by means of whose voltage fluctuations the wire feed via the control unit transmission is adjustable., ■

For a given cross-section of the mold is the. The amount of aluminum wire to be fed depends on the casting speed. The Gießgesehviindigkeit in turn is decisive for the running speed of the slab conveyor rollers. The voltage fluctuations in the slab conveying rollers indicating attracted speedometer machine so indicate precisely the casting speed. By utilizing these voltage fluctuations, a precisely dosed quantity of aluminum wire is achieved through transmission via the control device, the voltage fluctuations automatically causing a faster or slower wire feed.

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In this case, a first potentiometer, which is coupled to a first Rießgerät and adjustable to the maximum voltage that can be generated by the speedometer machine, is arranged in the control device, with a second potentiometer connected to the first and a third potentiometer coupled to a second measuring device connected to the second The thyristor control of the geared motor acts, the maximum voltage of which corresponds to the setpoint of the thyristor control of the geared motor "at the highest power, and the voltage reduction zx'fl see the set maximum voltage of the first and the maximum voltage of the third potentiometer via the second, '' the first and third potentiometer is compensable.

By reducing the voltage of the third potentiometer with the set maximum voltage of the first potentiometer and- the set equalizing voltage of the second potentiometer, the maximum desired wire feed can be regulated.

At the first potentiometer, the maximum voltage of the speedometer machine is that of .fall zu. Wall, is different and can normally be up to 60 V, adjustable. The third potentiometer acting on the thyristor control may, due to the capacity of the thyristor, deliver 6 V. The interposed potentiometer compensates for the voltage difference in such a way that regardless of the level of the existing maximum voltage of the tachomachine, which is set on the first potentiometer, the third potentiometer delivers 6 V at / full power and thus the highest power of the wire feeder can be achieved. By reducing the power of the third potentiometer, the maximum amount of wire fed can be set.

In the control unit, a connection and a circuit for initiating a replacement voltage is provided, through which the of

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the Stranggußmas machine over the speedometer machine delivered maximum voltage can be introduced into the control unit simultaneously, which means that the potentiometers can be adjusted. This can be advantageous the control unit can be set before the casting process, so that the automatic Regulation of the wire feed is available.

A fourth potentiometer and a circuit through which the remaining potentiometers are provided is provided in the control unit can be switched off and the fourth potentiometer is coupled to the second Keßgerät and the thyristor control of the Gear motor is done by hand via the fourth potentiometer. This control is used to regulate the wire feed during Casting on the mold, i.e. with the speedometer machine at a standstill.

Details of the invention are explained in drawings using an exemplary embodiment. . · '

It show: ■.

1 shows a schematic representation of a device according to the invention; ·

FIG. 2 shows the control plate of the device according to FIG. 1;

Fig. 3 is the circuit diagram of the control of the device according to FIG Λ.

Fig. M- the diagram of the dependence of the wire feed on the output voltage of the device of FIG.

As shown in Fig. 1, the device according to the invention consists of the control device 1, the reel 2 and the wire feed gear 3- A metal tube 4- is arranged on the wire feed gear 3, which carries the wire unwound from the reel feeds the melt. The wire feed gear 3 is off? management example designed in four stages, with the individual. Stages can be connected upstream manually. A motor 5 is blocked on the wire feed gear 3, its speed is thyristor controllable. '

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Essential parts for the invention and for setting the Control device 1 are the first potentiometer 6 with the first Measuring device the second potentiometer 8 and the third potentiometer 9 with the second measuring device 10. The potentiometers 6, 8-and-9 are connected in series, the input voltage being introduced into the first potentiometer and the third Potentiometer 9 the control voltage .for the thyristor control of the motor 5 is removed. A transformer 11 is also provided, Via which a substitute voltage for the input voltage can be introduced into the control unit 1. The equivalent voltage of the transformer 11 corresponds to the maximum occurring input voltage, which is 60 V at the most.

To switch on the control device, an on / off switch 12 is actuated. Then the control voltage of the third Set potentiometer 9. A preselection button is used for this 13 pressed, which the equivalent voltage from the transformer 11 in the control unit .introduces. On the first potentiometer. 6 is now the known -Ilaximal voltage of the speedometer machine Continuous casting machine discontinued. The set voltage can be read on the first heater 7. Then the third potentiometer 9 set to full power and the voltage gradient via the second, interposed potentiometer 8 between the first potentiometer 6 and the third potentiometer 9 regulated so that on the third potentiometer 9 whose maximum voltage is equal to 6 V .; On that but the third potentiometer is the output voltage for the motor 5 of the wire feed gear 5 to the desired Maximum wire feed reduced. The wire feed gear is in its maximum output and via the step switching designed in such a way that an excess of wire feed can be achieved 13 the backup voltage is switched off. The default of the Control unit 1 is thus completed.

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In the illustrated embodiment, the potentiometers 6, 8 and 9 as a Hegel potentiometer. In a not shown second Ausiührungsbeispiel the invention, the second potentiometer 8 is designed as a digital potentiometer, to a pre-programmed one with repetitive casting speed. Allow pre-setting.

In the control device 1 there is another, via the switch 15 fourth potentiometer which can be coupled to the second measuring device 10 16 arranged, via which the thyristor control of the motor 5 of the wire feed gear 3 can be done by hand. Of the Switch 15 has the switch position "fixed" and "automatic" where in the "fixed" switch position the control of the wire feed via the fourth potentiometer 16 and in the Switch position "automatic" via the first, second and third potentiometer 6, 8 and 9 takes place. This switch is also via a transmitter line 17 by a pulse transmitter on the control panel of the continuous casting machine switchable; when the continuous casting machine is switched on, the switching is carried out by the pulse generator takes place automatically from "fixed" to "automatic". The application of the control unit 1 from the speedometer machine takes place via the control line 18. Is on the control unit further connected the work sstromleiturig 19 that once via the transformer. 11 generates the equivalent voltage and on the other hand the motor 5 of the wire feed gear 3 with the interposition of the control unit 1 and the thyristor control via the Working power line 20 drives.

Before the mold is cast on, the control unit 1 is controlled via the Switch 12 switched on, the fixed adjustable feed first becoming effective, so that when filling the Kxfkille the wire feed via the fourth potentiometer 16 and the thyristor control acted upon by it takes place because the continuous casting machine still stands still and no control current over the Speedometer machine is delivered. The fourth potential

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meter 16 taking place. Wire feed or the wire feed speed is set according to empirical values. When the mold is opened, that is when the continuous casting machine is switched on control unit 1 is switched to "strand down" by the. Impulse contact via the encoder line 1? automatic to "automatic" switched. This switching state is retained until the end of the casting process. ·

If the input voltage fluctuates,. From the speedometer machine, the indicates a changed casting speed, the voltage present at the output of the third potentiometer 9 drops in the extreme case when the speedometer machine is at a standstill, which indicates a pouring stop, to zero. The wire feed is in this pall. The entire range from zero to maximum is thus available at the output of the control device or of the third potentiometer 9: casting speed equal to zero up to the set controlled variable for the control of the Hotors 5 cLes wire feed gear J for Disposal. The ratio of the voltage at the output of the third potentiometer 9 to the casting speed falls and increases linearly as in I? ig. 4- shown.

Claims

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Claims (7)

Claims 1. Device for feeding an additional material to a Base material in the casting process, especially "in continuous casting by means of a permanent mold and a continuous casting machine, the additional material preferably when pouring the base material into the mold in the form of wire or strip material Casting from a reel through a switchable and continuously adjustable, motor-driven.and. thyristor-controlled praht feed gear is fed in front of the mold, characterized in that the wire unwinding from a reel (2) Gear (3) is preceded by a control unit (1) that controls the wire feed speed as a function of the casting speed regulates automatically. 2. - Device according to claim 1, characterized in that to the slab conveyor rollers which are driven by the continuous casting machine and which convey the strand emerging from the mold in a known manner a tachometer for measuring the casting speed is blocked by means of their voltage fluctuations The wire feed gear (3) can be regulated via the control unit (1). 3. Device according to claims 1 and 2, characterized in that in the control device (1) a first, with a first measuring device (7) coupled to the maximum voltage generated by the speedometer adjustable potentiometer (6) is arranged that the first a second potentiometer (8> and the second a third potentiometer (9) coupled with a second measuring device (10) is connected, which acts on the thyristor control of the geared motor and whose maximum voltage ■■ corresponds to the setpoint of the thyristor control of the geared motor Joel highest power and that about the second, the first _. 2 509827/0345 and third potentiometer (6 and 9) interposed potentiometer (8) the voltage reduction between the set maximum voltage of the first and the maximum voltage of the third potentiometer (6 or 9) can be compensated. 4-. Device according to claims 1 to 3? marked in that by reducing the voltage of the third potentiometer (9) when the maximum voltage of the first potentiometer is set (6) and the set compensation voltage of the second potentiometer (8) the maximum desired wire feed is adjustable. 5. Device according to claims 1 'to 4-, characterized in that a connection and a circuit for introducing an equivalent voltage are provided in the control unit (1), over the ones from the continuous casting machine over the speedometer machine The maximum voltage output can be fed into the control unit (1) simultaneously which means that the potentiometers (6, 8 and 9) can be preset. ■ 6. Device according to claims 1 to 5 »characterized in that a fourth potentiometer (16) and a circuit through which the remaining Potentiometers (6, 8 and 9) can be switched off and the fourth potentiometer (16) with the second measuring device (10) is coupled and the thyristor control of the geared motor is carried out by hand via the fourth potentiometer (1 (5)). 7. Device according to claims 1 to 6, characterized in that the circuit of the fourth potentiometer (16) is connected to a pulse generator on the control panel of the continuous casting machine ₃ whereby when the continuous casting machine is switched on, the fourth potentiometer (16) can be switched off and the circuit for the first three potentiometers (6, 8 and 9) can be switched on. ■ -. 509827/0345 , ■ ^J 1 -ι. Blank page