阅读说明：本技术 一种连铸中间包等离子加热的等电位控制装置及方法 (Equipotential control device and method for plasma heating of continuous casting tundish ) 是由 宋景欣 王勇 李京社 杨树峰 于 2018-09-04 设计创作，主要内容包括：本发明涉及一种连铸中间包等离子加热的等电位控制装置及方法,属于金属板坯连铸的工艺设备技术领域。一种连铸中间包等离子加热的等电位控制装置,装置由PLC控制系统控制,中间包内含有渣层和钢液,包括预埋在中间包的耐火材料层之间的钢线,钢线连接至PLC控制系统的零电位采样点,钢线的一端在中间包的底部漏出约3~5mm,钢线的另一端连接有镀锌圆钢,并与中间包外壳可靠连接,镀锌圆钢连接有绝缘软导线,绝缘软导线连接有电极,电极安装在升降装置上,PLC控制系统连接并控制升降装置。本发明通过钢液升高或降低时的液面变化,PLC系统能够及时进行反馈和调节,控制电极的升高或降低,以保障电弧长度的有效变化,保证了加热的稳定。(The invention relates to an equipotential control device and method for plasma heating of a continuous casting tundish, belonging to the technical field of process equipment for continuous casting of metal slabs. The utility model provides an equipotential controlling means of package plasma heating in middle of continuous casting, the device is controlled by PLC control system, contain slag blanket and molten steel in the middle package, including pre-buried copper wire between the refractory material layer of package in the middle of, the copper wire is connected to PLC control system's zero potential sampling point, the one end of copper wire spills about 3~5mm in the bottom of package in the middle, the other end of copper wire is connected with the galvanized round steel, and reliably be connected with middle package shell, the galvanized round steel is connected with insulating flexible conductor, insulating flexible conductor is connected with the electrode, the electrode mounting is on elevating gear, PLC control system connects and controls elevating gear. According to the invention, through the liquid level change when the molten steel rises or falls, the PLC system can feed back and adjust in time and control the rise or fall of the electrode, so that the effective change of the arc length is ensured, and the heating stability is ensured.)

1. The utility model provides a package plasma heating's equipotential control device in middle of continuous casting, the device is controlled by PLC control system, contain slag blanket and molten steel in the middle package, its characterized in that, including pre-buried the copper wire between the refractory material layer of middle package, the copper wire is connected to PLC control system's zero potential sampling point, the one end of copper wire is in the bottom of middle package spills about 3~5mm, the other end of copper wire is connected with the galvanized round steel, and with middle package shell is reliably connected, the galvanized round steel is connected with insulating flexible conductor, insulating flexible conductor is connected with the electrode, the electrode is installed on elevating gear, PLC control system connects and controls elevating gear.

2. The plasma-heated equipotential control device for a continuous casting tundish according to claim 1, wherein: the electrode comprises an anode and a cathode, the electrode is connected with an external power supply, a resistor and an ammeter are connected in series between the electrode and the insulated flexible lead, and the resistor is connected with a voltmeter in parallel.

3. The plasma-heated equipotential control device for a continuous casting tundish according to claim 1, wherein: the tundish is positioned above the molten steel and is provided with a fixed position point A, and the height of the position point A relative to the inner bottom of the tundish is recorded as H_AThe liquid level of the molten steel is provided with a position point B, and the height of the position point B relative to the inner bottom of the tundish is recorded as H_B。

4. A method of rectifying a deviation according to the apparatus of claim 3, characterized by performing the steps of:

the method comprises the following steps: the lifting device controls the electrode to descend;

step two: when the electrode contacts the molten steel, the voltmeter indicates that the voltage is approximately 0V;

step three: the PLC control system calculates the distance D of the electrode descending from the position point A to the position point B_ABAccording to the formula: h_B=H_A- D_AB；

Step four: during the plasma arc starting process of the tundish; when the anode is positioned at a position point A, the PLC control system assigns a coordinate value of the position point A to the anode, and the voltmeter indicates that the voltage is more than 100V;

step five: the lifting device controls the electrode to descend until the electrode is close to a slag layer, when the anode is contacted with the surface of the slag layer, the anode is conducted with the slag layer and the molten steel in a heat radiation state of high-temperature molten steel at 1500 ℃, the voltage of the anode is rapidly reduced and is only about 5-10V, and because of serial partial pressure, the voltage drop on the resistance of the slag layer is only 5-10V;

step six: the voltage corresponding to the cathode at high level will increase by about one time while the anode is close to the steel level, the voltmeter indicating above 200V;

step seven: the lifting device continuously controls the electrode to descend, the cathode gradually descends from a high position at the moment, and when the cathode reaches a position point A, the PLC control system assigns the coordinate value of the position point A to the cathode;

step eight: the cathode continuously and slowly descends, and when the cathode is about 3mm away from the slag layer, the cathode discharges the slag layer to generate a plasma arc in a 1500 ℃ environment;

when plasma arcs are generated, the voltage corresponding to the cathode is rapidly reduced, the current is rapidly increased and reaches a preset working current, and the heating power is rapidly increased from 0;

step nine: then controlling the cathode to automatically lift upwards by the lifting device, wherein the cathode voltage display is gradually increased, and the electrode is in a stable state after the set arc length is reached;

step ten: in a heating state, the lifting device controls the motor to ensure the length of the electric arc;

presetting the arc length corresponding to the unit voltage drop of the electrode as L_Sheet；

Step eleven: here, the arc voltage of the anode is set to U_{Yang (Yang)}The length of the anode plasma arc (namely the height distance of the anode electrode tip from the liquid level of the steel) is D_{Yang (Yang)}Arc voltage of the cathode is U_{Yin (kidney)}The length of the cathode plasma arc (namely the height of the cathode electrode head from the molten steel) is D_{Yin (kidney)}According to the formula:

D_{yang (Yang)}= L_Sheet* U_{Yang (Yang)}；

D_{Yin (kidney)}= L_Sheet* U_{Yin (kidney)}；

Step twelve: when the liquid level of the molten steel rises, the distance between the electrode and the liquid level of the molten steel is smaller and smaller, meanwhile, the arc length of the electrode is shortened, the arc voltage is reduced, the PLC control system automatically adjusts according to the arc voltage fed back, the electrode is lifted, the arc voltage is increased, and the arc length is always stabilized in a set range; and in a similar way, when the liquid level of the molten steel descends, the arc length of the electrode can be lengthened, the arc voltage can also rise, and the PLC control system controls the electrode to descend and enables the arc voltage to be reduced.

Technical Field

The invention relates to an equipotential control device and method for plasma heating of a continuous casting tundish, belonging to the technical field of process equipment for continuous casting of metal slabs.

Background

The tundish is a key device which is used as a buffer device before liquid metal is solidified and formed on a continuous casting machine, has the functions of linking up the supply of molten metal, improving the cleanliness of the molten metal and the like, and plays a decisive role in the quality and the production efficiency of steel products.

Pouring of molten metal in a tundish at constant temperature is an important target in continuous casting production, and is a necessary condition for ensuring the quality of continuous casting billets and stable and smooth production. In the existing tundish plasma heating equipment, the temperature of molten metal in a tundish is difficult to ensure to be stable under the condition of no external supplement, and the fluctuation range of the molten metal reaches 40 ℃. In order to keep the temperature of the molten metal in the tundish constant in the production process, plasma arcs are generated by electrodes to heat the molten metal. In order to achieve stable heating, a reasonably reliable control method needs to be adopted.

Disclosure of Invention

The invention aims to solve the technical problem that aiming at the defects of the prior art, the invention provides a control device and a control method which are more reliable, stable and reasonable when a tundish is heated by plasma at present.

In order to achieve the purpose, the technical scheme adopted by the method is as follows: the utility model provides a package plasma heating's equipotential control device in middle of continuous casting, the device is controlled by PLC control system, contain slag blanket and molten steel in the middle package, including pre-buried be in the copper wire between the refractory material layer of middle package, the copper wire is connected to PLC control system's zero potential sampling point, the one end of copper wire is in spill about 3~5mm in the bottom of middle package, the other end of copper wire is connected with the galvanized round steel, and with middle package shell is reliably connected, the galvanized round steel is connected with insulating flexible conductor, insulating flexible conductor is connected with the electrode, the electrode is installed on elevating gear, PLC control system connects and controls elevating gear.

The further improvement of the technical scheme is as follows: the electrode comprises an anode and a cathode, the electrode is connected with an external power supply, a resistor and an ammeter are connected in series between the electrode and the insulated flexible lead, and the resistor is connected with a voltmeter in parallel.

The further improvement of the technical scheme is as follows: the tundish is arranged above the molten steelThere is a fixed position point A, the height of the position point A relative to the inner bottom of the tundish is marked as H_AThe liquid level of the molten steel is provided with a position point B, and the height of the position point B relative to the inner bottom of the tundish is recorded as H_B。

The deviation rectifying method of the device comprises the following steps:

the method comprises the following steps: the lifting device controls the electrode to descend.

Step two: when the electrode contacts the molten steel, the voltmeter indicates that the voltage is approximately 0V.

Step three: the PLC control system calculates the distance D of the electrode descending from the position point A to the position point B_ABAccording to the formula: h_B=H_A- D_AB。

Step four: during the plasma arc starting process of the tundish; when the anode is at a position point A, the PLC control system assigns the coordinate value of the position point A to the anode, and the voltmeter indicates that the voltage is more than 100V.

Step five: the lifting device controls the electrode to descend until the electrode is close to the slag layer, when the anode is in contact with the surface of the slag layer, the anode is conducted with the slag layer and the molten steel in a heat radiation state of high-temperature molten steel at 1500 ℃, the anode voltage is rapidly reduced and is only about 5-10V, and because of serial partial pressure, the voltage drop on the resistance of the slag layer is only 5-10V.

Step six: the voltage corresponding to the cathode at high will increase by approximately a factor of two while the anode is close to the steel level, the voltmeter indicating above 200V.

Step seven: and the lifting device continuously controls the electrode to descend, the cathode gradually descends from a high position at the moment, and when the cathode reaches the position point A, the PLC control system assigns the coordinate value of the position point A to the cathode.

Step eight: and the cathode continuously and slowly descends, and when the cathode is about 3mm away from the slag layer, the cathode discharges the slag layer to generate a plasma arc in a 1500 ℃ environment. When the plasma arc is generated, the voltage corresponding to the cathode is rapidly reduced, the current is rapidly increased and reaches the preset working current, and the heating power is rapidly increased from 0.

Step nine: then the lifting device controls the cathode to automatically lift upwards, the cathode voltage display is gradually increased, and when the set arc length is reached, the electrode is in a stable state.

Step ten: and in a heating state, the lifting device controls the motor to ensure the length of the electric arc. Presetting the arc length corresponding to the unit voltage drop of the electrode as L_Sheet。

Step eleven: here, the arc voltage of the anode is set to U_{Yang (Yang)}The length of the anode plasma arc (namely the height distance of the anode electrode tip from the liquid level of the steel) is D_{Yang (Yang)}Arc voltage of the cathode is U_{Yin (kidney)}The length of the cathode plasma arc (namely the height of the cathode electrode head from the molten steel) is D_{Yin (kidney)}According to the formula:

D_{yang (Yang)}= L_Sheet* U_{Yang (Yang)}；D_{Yin (kidney)}= L_Sheet* U_{Yin (kidney)}。

Step twelve: when the liquid level of the molten steel rises, the distance between the electrode and the liquid level of the molten steel is smaller and smaller, meanwhile, the arc length of the electrode is shortened, the arc voltage is reduced, the PLC control system automatically adjusts according to the arc voltage fed back, the electrode is lifted, the arc voltage is increased, and the arc length is always stabilized in a set range; and in a similar way, when the liquid level of the molten steel descends, the arc length of the electrode can be lengthened, the arc voltage can also rise, and the PLC control system controls the electrode to descend and enables the arc voltage to be reduced.

The invention has the following beneficial effects: through the liquid level change when the molten steel rises or falls, the PLC system can feed back and adjust in time, and the rising or the falling of control electrode to guarantee the effective change of electric arc length, guaranteed the stability of heating.

Drawings

The invention will be further described with reference to the accompanying drawings.

FIG. 1 is a schematic structural view of an equipotential control device for plasma heating of a continuous casting tundish according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of the circuit structure of fig. 1.

Detailed Description

The following description of the embodiments with reference to the accompanying drawings will provide further detailed description of the embodiments of the present invention, such as the mutual positions and connection relationships between the related parts, the functions and working principles of the parts, and the operation and use methods, to help those skilled in the art to more completely, accurately and deeply understand the concept and technical solutions of the present invention.