Apparatus and method for controlling horizontal oscillation of an edge dam of a twin roll strip caster
An apparatus and method for controlling the horizontal oscillation of an edge dam of a twin roll strip caster is provided. The apparatus includes an oscillation unit which horizontally oscillates an oscillation plate in accordance with an oscillation waveform so that an edge dam refractory coupled to the oscillation plate horizontally oscillates, a servo valve which outputs the oscillation waveform to the oscillation unit, and a control unit which applies the oscillation waveform to the servo valve, thus controlling the horizontal oscillation of the oscillation unit. The amplitude, frequency and waveform of the oscillation are variably controlled depending on casting conditions. The edge dam horizontally oscillates, using the servo valve and a hydraulic cylinder, thus rapidly removing edge skull and suppressing the generation and growth of skull, thereby preventing a casting roll or edge dam from being damaged.
1. An apparatus for controlling horizontal oscillation of an edge dam of a twin roll strip caster, the apparatus comprising:
an oscillation unit horizontally oscillating an oscillation plate in accordance with an oscillation waveform so that an edge dam refractory coupled to the oscillation plate horizontally oscillates;
a servo valve outputting the oscillation waveform to the oscillation unit to perform the horizontal oscillation; and
a control unit applying the oscillation waveform to the servo valve, thus controlling the horizontal oscillation of the oscillation unit,
wherein the control unit comprises:
an oscillation information collector collecting from an HMI (Human Machine Interface) information about an ON/OFF status of the oscillation, and an amplitude, a frequency and a waveform of the oscillation;
an oscillation waveform generator generating, using the information received from the oscillation information collector, a reference of the oscillation waveform having an amplitude and a frequency that are required to control the horizontal oscillation; and
a horizontal oscillation controller controlling the servo valve both using the information about the oscillation waveform received from the oscillation waveform generator and using information about a position of the oscillation unit that is received from an oscillation-unit-displacement measuring device, thus controlling the horizontal oscillation of the oscillation unit.
2. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 1 , wherein the oscillation unit comprises:
a main body installed with a hydraulic line;
a hydraulic cylinder fastened to the main body;
a cylinder rod placed through the hydraulic cylinder so as to be movable to opposite sides of the hydraulic cylinder; and
a support connecting opposite ends of the cylinder rod to opposite ends of the oscillation plate.
3. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 1 , wherein the control unit further comprises a ramping unit varying at constant rates the amplitude and the frequency of the reference of the oscillation waveform generated from the oscillation waveform generator.
4. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 3 , wherein the amplitude of the oscillation waveform ranges from 10 μm to 1,500 μm, and the frequency ranges from 0.1 Hz to 20 Hz.
5. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 1 , wherein the control unit further comprises an oscillation-unit-center measuring device transmitting information about a center position of the oscillation unit to the horizontal oscillation controller.
6. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 1 , wherein the oscillation-unit-displacement measuring device transmits information about a real time position of the oscillation unit to the control unit.
7. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 6 , wherein the oscillation waveform comprises a sine wave, a rectangular wave or a triangular wave.
8. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 6 , wherein the amplitude of the oscillation waveform ranges from 10 μm to 1,500 μm, and the frequency ranges from 0.1 Hz to 20 Hz.
9. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 1 , wherein the oscillation waveform comprises a sine wave, a rectangular wave or a triangular wave.
10. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 9 , wherein the amplitude of the oscillation waveform ranges from 10 μm to 1,500 μm, and the frequency ranges from 0.1 Hz to 20 Hz.
11. The apparatus for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 1 , wherein the amplitude of the oscillation waveform ranges from 10 μm to 1,500 μm, and the frequency ranges from 0.1 Hz to 20 Hz.
12. A method for controlling horizontal oscillation of an edge dam of a twin roll strip caster, the method comprising horizontally oscillating an oscillation plate using a servo valve and a cylinder in accordance with an oscillation waveform so that an edge dam refractory coupled to the oscillation plate horizontally oscillates, thus eliminating a zone which does not oscillate, and reducing edge skull, wherein the horizontally oscillating comprises:
an operation of selecting information about an ON/OFF status of the oscillation, and an amplitude, a frequency and a waveform of the oscillation using an HMI (Human Machine Interface) monitor;
a slow loop operation of collecting the information selected using the HMI monitor and transmitting the information to a medium loop;
a medium loop operation of generating, using the information received from the slow loop, a reference of the oscillation waveform having an amplitude and a frequency that are required to control the horizontal oscillation, and transmitting the reference to a fast loop; and
a fast loop operation of controlling the servo valve both using the information about the reference of the oscillation waveform received from the medium loop and using information about a position of an oscillation unit received from an oscillation-unit-displacement measuring device, thus controlling horizontal oscillation of the oscillation unit.
13. The method for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 12 , wherein the horizontally oscillating further comprises horizontally oscillating the oscillation plate such that at an initial stage of casting, an amplitude of the oscillation is maintained within a range from 500 μm to 1,200 μm, and after the initial stage has passed, the amplitude is maintained within a range from 200 μm to 600 μm, and at a final stage of the casting, the amplitude is maintained within a range from 400 μm to 700 μm.
14. The method for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 13 , further comprising reducing the frequency of the oscillation waveform or changing the oscillation waveform from a sine wave into a rectangular or triangular wave, thus minutely controlling the amplitude of the oscillation waveform.
15. The method for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 12 , further comprising reducing the frequency of the oscillation waveform or changing the oscillation waveform from a sine wave into a rectangular or triangular wave, thus minutely controlling the amplitude of the oscillation waveform.
16. The method for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 12 , wherein the medium loop operation comprises varying the amplitude and frequency of the reference of the oscillation waveform at constant rates, and transmitting the information about the reference of the oscillation waveform to the fast loop.
17. The method for controlling the horizontal oscillation of the edge dam of the twin roll strip caster according to claim 12 , wherein the fast loop operation comprises controlling the horizontal oscillation of the oscillation unit in a period of 0.001 or less.