SU1717277A1 - Process for continuous casting of metal band - Google Patents

Abstract

The invention relates to foundry and can be used in the process of continuous casting metal strip. The purpose of the invention is to improve the quality of a metal tape and simplify its production technology. The method consists in continuously measuring the current quality of the induction heater with sensors 7 and 8 during the casting process. The reducer 10 controls the gas pressure applied to the surface of the liquid metal in proportion to the quality factor of the induction heater. 1 il.

Description

The invention relates to foundry and can be used in the technological process of continuous casting of metal tape.

The purpose of the invention is to improve the quality of the metal tape and simplify the technology for its production.

The drawing shows a schematic diagram of a device that implements the method.

The device comprises an alternating current generator 1, a load oscillating circuit 2, formed by a battery of compensating capacitors 3 and an induction heater consisting of an inductor 4 and a sealed crucible 5 with metal, a measurement unit 6 with sensors 7 and 8 of the current of the load oscillating circuit current generator. control unit 9, controlled gearbox 10 and cooling rapidly rotating surface 11.

The method is based on the dependence of the quality factor of an induction heater with a crucible filled with metal on the amount of metal in the crucible. An induction heater with metal system can be considered as a classic example of a parallel oscillatory circuit, the inductor of which has a ferromagnetic or paramagnetic core. Inductor - an inductor for melting metal in a crucible. The column of molten metal in the crucible is the core. The process of metal release from the crucible is similar to the extension of the core from the inductor, which significantly changes the quality factor of the parallel oscillatory circuit.

This makes it possible to use the induction heater itself directly as a sensor and not to introduce a special sensor as in the known one, which simplifies the installation design and allows the crucible to be fixed rigidly. metal, thereby eliminating the possibility of both vertical oscillations of the crucible and oscillations of the jet of metal released from the crucible, which improves the quality of the resulting metal strip.

The device operates as follows.

During the technological process of metal release and obtaining a metal strip, sensors 7 and 8 continuously measure the current quality factor of the induction heater. The quality factor of the induction heater is equal to the quality factor of the load oscillating circuit 2 formed by the inductor 4 with a battery of compensating capacitors 3, and characterizes the relative amount of energy stored in the oscillatory circuit and the energy spent in the loss resistance of this circuit for one period. The quality factor is equal to the ratio of the wave impedance to the loss resistance of this circuit and is determined by the expression q = A = ^ω ° ^L = ¹

Rn Rn Шо C Rn where Q is the quality factor of the circuit;

p is the wave impedance of the circuit;

L is the inductance of the circuit;

C is the capacitance of the capacitor bank; Rn is the loop loss resistance;

ω ₀ is the frequency of natural oscillations of the circuit.

With a high degree of accuracy, the quality factor of the oscillatory circuit can be defined as the ratio of the magnitude of the loop current to the magnitude of the current consumed from the source, i.e. at resonance, the loop current is Q times the current consumed from the generator.

Block 6 measurements with sensors 7 and 8 measures the value of the current quality factor of the induction heater. As the metal is released, the quality factor increases, since the losses in the circuit decrease. The signal from the measurement unit 6 is supplied to the control unit 9 of the gearbox 10. The gearbox 10 controls the gas pressure applied to the surface of the molten metal in proportion to the quality factor of the induction heater.

Block 6 measurements is a classic phase-sensitive rectifier, the signal of which is proportional to the phase shift between the output current of the alternator 1 and the current of the load oscillating circuit 2.

The output signal of the measuring unit 6 is input to the control unit 9. One of the options for constructive execution of the control unit 9 may be a well-known technical solution, made on the basis of executive electric motors with a drive.

The control unit 9 functionally consists of an input signal amplifier and an actuator, which is used as an actuator. The motor shaft is connected to the shutter of the controlled gearbox. As the flow of liquid metal from the sealed crucible 5, the quality factor of the load oscillating circuit 2 increases. This leads to an increase in the output signal of the measuring unit and an increase in the acting signal on the actuator motor, the rotation speed of which is proportional to the value of the output voltage (signal). In this case, the executive electric motor opens the controlled gearbox, increasing its cross-section and thereby increasing the gas pressure in the crucible. Thus, an increase in the quality factor leads to an increase in gas pressure in an airtight crucible.

Claims (1)

Claim A method of continuous casting of a metal strip, comprising melting the metal with an induction heater in an airtight crucible equipped with a nozzle, draining the metal through the nozzle onto the moving surface of the cooling element by changing the gas pressure on the surface of the liquid metal and producing a thin ribbon during fast cooling, 5 characterized in that In order to improve the quality of the tape and simplify the technology of its production, in the process of metal discharge, the current quality factor of induction heating is continuously monitored10 scrap and change the gas pressure on the metal surface in proportion to the quality factor of the induction heater with the metal.