SU1342589A1 - Method of controling metal casting in electric magnetic field - Google Patents

Abstract

The invention relates to metallurgy and is intended to control the continuous and semi-continuous casting of metal, predominantly with the formation of an ingot by the inductor electromagnetic field. The purpose of the invention is to improve the accuracy of the size of the ingot. The essence of the invention is that during the casting process the current of inductor 2 is measured by sensor 6 and the current of RL-chain by sensor 7, the phase difference between the indicated currents in phase meter 8 is determined. The voltage of the inductor 2 varies sweat using the control unit 9 and the converter TO, depending on the value of the signal at the output of the meter, phase 8. 1 il. $ d // x

Description

one

The invention relates to ferrous and non-ferrous metallurgy and can be used in pouring metals in an electromagnetic crystallizer.

(zmk).

The purpose of the invention is to improve the accuracy of the size of the ingot.

The drawing shows a block diagram of a device implementing the method.

The metal ingot 1 is located in the EMC inductor 2, in parallel to which are connected a compensating capacitor 3 and an auxiliary RL chain, consisting of chokes 4 and a variable resistor 5, B branch, inductor and auxiliary RL depochka, current and current sensors B and 7, signals from which a phase converter 10 connected in parallel with the capacitor 3 is connected to the phase meter 8 connected to the unit 9,

The process control system for casting metal ingots in an EMC with the stabilization of a given ingot size, d works as follows.

When the system is preset in inductor 2 of the crystallizer 30, an ingot with a desired size dp is found. In this case, the inductance of the inductor with a metal 9 e active resistance Rjjo. When applied to the inductor 2, the voltage U from the power source 10 gg

but

the inductor flows the current of the first ory is determined by the formula

cool,

phase

Cf arctg

R

BUT

HO

(one)

where QO is the angular frequency.

At the same time, an auxiliary current flows through the auxiliary RL-n, eno4Ke. The inductance L is chosen for reasons of reducing losses by an order or several orders of magnitude greater than the inductor with a metaplate (for example, Ln LHO), while the variable resistance R is chosen so that the quality factor of the auxiliary circuit is equal to the quality factor of the inductor,

R n R

but

In this case, the phase

auxiliary circuit

arctg- 1-kip

(2)

This adjustment point is determined by the coincidence of the phases of the signals.

13A25892

coming from sensors 6, the input of the meter 8 phase, and the signal at its output.

When casting, if there is a deviation of the ingot diameter d

d from given

d, for example, the diameter increases (d dj,), then the inductance of inductor 2 with metal 1 decreases, and the resistance increases. The phase of the inductor current in this case

arctg

"About LH,

R

HI

M

but j

and the phase of the auxiliary circuit current remains almost unchanged. Co, C of the phase meter 8 in this case receives the signal M HI О to the converter control unit 9, leading to an increase in the output power of the converter 10, an increase in the voltage on the inductor 2 and, consequently, to an increase in the crimping force of the EMC field.

The ingot diameter is reduced to a value of do. At no other diameter of the ingot phase (Jf × K are equal to each other, since with a change in the diameter of the ingot, the inductance of the inductor with the metal Lj increases or decreases, and the active Resistance R, on the contrary, decreases or increases, respectively. Consequently, their ratio is

TO,

can not

to repeat. Each diameter of the ingot corresponds to its good quality circuit

inductor

LV,

-but

R

To

and c,

.four

8SP

In this case, the phases of the current of the inductor and the auxiliary circuit are equalized and the signal at the output of the phase meter 8 is again absent.

If the ingot diameter is less than dg, the inductance of the inductor 2 becomes unstable, and the active resistance decreases (the phase of the current and) of the inductor c increases and curnaJT from the output of the phase meter

H Vsp - H

ig

0

1342589

arriving at the output of control block 9

converter 10, leads to a decrease in the output power of the converter, a decrease in the voltage on the inductor and a decrease in crimping force of the 3MKi field

The ingot diameter increases to. dp. In this case, n - Ch n - - The advantage of the method is the invariance to the cause of the change in the diameter of the ingot (metal overflow or fluctuation of the mains voltage). Unlike the known method (in the proposed method, changing the frequency of the voltage on the inductor does not change the control signal, therefore, does not introduce an error in the adjustable diameter of the ingot, since the frequency is included in both signals

CjLa, -n

H .sp arctg

R

vsp

)

cf arctg

coLi

L

vsp

Bh

with equality of relations- s

Q / .n

Vsp

main circuit and at any frequency.

.- l-H

 arctp

 Bh

R

ecn

does not depend on frequency.

Editor P.Geershi Order 4549/8

Compiled by A.Abrosimov

Tehred And, Popovich Proofreader A.T.

Circulation 740 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

The method of controlling continuous and semi-continuous casting of metals was tested in an induction-thyristor casting complex during casting of round ingots of small diameter.

0

five

0

five

0

five

As a power source, frequency-controlled transducers 6 and

the applicant is 1ShCh-20-2.4.

7 - TICHL2 current transformers and phase difference meter F2-13.

I

The deviation of the diameters of the cast ingots is less than 0.2 mm.

Claims (1)

Invention Formula The method of controlling the casting of a metal in an electromagnetic field is mainly with a resistance-inductance circuit connected in parallel to the inductor, including measuring the current of the inductor, determining the phase difference and controlling the voltage of the inductor as a function of the measured size of the ingot, characterized in that ingot, in addition, the current in the circuit is the resistance - inductance, the phase difference between the current of the inductor and the current in the circuit is determined - the resistance - inductance, and the voltage inductance The orifices are changed according to the phase difference between the inductor current and the current in the resistance-inductance circuit.