KR100270391B1 - Immersion depth control device of immersion nozzle and its control method - Google Patents

Abstract

PURPOSE: An apparatus and a method for controlling an immersion depth of an immersion nozzle are provided which measures and controls a real-time immersion depth of the immersion nozzle considering consistently changing mold level and facility conditions. CONSTITUTION: The apparatus comprises indicators each of which are installed at the upper part of a local panel and the upper part of the outer circumference of a tundish, a position detector detecting the ascending and descending positions of the tundish, a mold level detector detecting a mold level, a DCS (level 1 computer) (16) outputting the calculated immersion depth by calculating an immersion depth of an immersion nozzle after inputting position detected values of the position detector and mold level values of the mold level detector; and a tundish PLC (17) and a tundish up/down controller (18) controlling upper and lower levels of the tundish according to outputs of the DCS (16). The method comprises the processes of measuring an upper and lower transfer distance of a tundish with a position detector; correcting a facility constant per tundish car by detecting a mold level with a mold level detector; calculating immersion depths of an immersion nozzle per each strands with a DCS (level 1 computer) (16); and controlling an immersion depth of an immersion nozzle by controlling upper and lower transfer of the tundish with a tundish PLC (17) and a tundish up/down controller (18) depending on the calculated immersion depth of the immersion nozzle.

Description

Immersion depth control device of immersion nozzle and its control method

1 is a cross-sectional view of a tundish provided with an indicator and a position detector according to the present invention.

2 is a block diagram of the immersion depth control device of the present invention immersion nozzle.

3 is a structural diagram of a position detector according to the present invention.

4 is a view for explaining a method for calculating the immersion depth of the deposition nozzle according to the present invention.

Figure 5 is a flow chart of the operation of the immersion depth control device of the immersion nozzle of the present invention.

* Explanation of symbols for main parts of the drawings

1: tundish car moving unit 2: tundish car fixing unit

3: tundish 4: driving motor

5: mold 6: immersion nozzle

7: tundish shift wheel 8: local panel

9: piston 10: long nozzle

11, 12, 13: Indigate 14: position detector

15: mold level detector 16: DCS (Level 1 computer)

17: tundish PLC 18: tundish up / down controller

Detailed description of the invention

[Purpose of invention]

[Technical field to which the invention belongs and the prior art in that field]

The present invention relates to a method and apparatus for measuring and controlling the immersion depth of a immersion nozzle for supplying molten steel into a mold. In particular, the present invention relates to a immersion depth of a real time immersion nozzle in consideration of continuously changing mold level and equipment conditions. The present invention relates to an apparatus for controlling the immersion depth of a deposition nozzle for measuring and controlling the same, and a control method thereof.

Generally, the immersion nozzle is a refractory tube used to prevent molten steel reoxidation by the atmosphere during the movement of the molten steel between the tundish and the mold, and serves to supply the molten steel into the mold where the solidification starts.

Tubes, that is, molten steel injected into the mold through the immersion nozzle, are shaped according to physical characteristics such as temperature and composition of the molten steel, and the discharge port size and shape at both ends of the immersion nozzle, casting width, and immersion depth of the immersion nozzle. This is determined and acts as a direct factor in forming the inclusion stack during the solidification process. Although the forming elements of such molten steel can be measured and controlled in most cases except in abnormal operation such as clogging of nozzles, the immersion depth of the immersion nozzle has not been automated until now.

Therefore, the conventional method of managing the immersion depth of the immersion nozzle is that the operator descends to a predetermined position in the local panel (LOCAL PANEL) according to the reference value at the beginning of casting, and there is a high possibility of deviation between the operators and the tundish car (T / D CAR). When an error occurs due to characteristics, correction is difficult, and there is a possibility of malfunction due to manual operation. In addition, since the level of molten steel in the mold is continuously changed during casting, it is difficult to measure the immersion depth of the deposition nozzle which changes with time during casting. Therefore, when different mold level standards are set among workers, the immersion depth measurement deviation of the immersion nozzle becomes larger, and when the immersion depth standard that is generally managed is 160mm ~ 180mm, when the deviation occurs more than 10%, it is not meant to comply with the standard. As a result, quality improvement due to standardization of operations cannot be expected.

In addition, in the SLAG LINE correction work performed to prevent the dropping of the deposition nozzle due to the loss of the deposition nozzle, the manual operation using the local panel increases the variation among workers. The immersion depth optimization task makes it difficult to obtain accurate immersion depth measurement values of the immersion nozzles and makes it difficult to evaluate the quality of the product because of difficulty in taking into account the continuously changing mold surface level and the inability to detect deviations between workers. Even if the measured value of the hot water surface is taken into consideration, it is not possible to provide the self-correction means by the deterioration and deformation of the tundish car as described above, and to cover the front, rear, left and right flow of the tundish car itself. If the immersion depth value of the immersion nozzle is not measured, the measurement itself becomes meaningless due to an incorrect measurement value.

The present invention has been invented to prevent operation and quality deviation caused by the measurement of the immersion depth of the immersion nozzle by manual operation in consideration of the above circumstances, in consideration of the continuously changing mold level and equipment conditions immersion depth of the real time immersion nozzle It automatically reduces the work removal and work deviation by automatically setting the immersion depth of the initial immersion nozzle using the measured depth of immersion nozzle. An object of the present invention is to provide an apparatus for controlling the immersion depth of a deposition nozzle and a control method thereof.

Immersion depth control apparatus of the present invention immersion nozzle for achieving the above object is a tundish moving unit (1) and tundish cargo fixing unit (2), tundish (3), drive motor (4), mold (5), In the playing equipment provided with a immersion nozzle 6, a tundish moving wheel 7, a local panel 8, a piston 9 and a long nozzle 10, the upper part of the local panel 8 and a tundish The indicators 11, 12, and 13 provided on the outer periphery of (3), the position detector 14 for detecting the up-down position of the tundish 3, and the mold for detecting the mold level, respectively. DCS (Level 1 computer) which calculates and outputs the immersion depth of the deposition nozzle 6 by inputting the level detector 15, the position detection value of the position detector 14, and the mold level value of the mold level detector 15; ), A tundish PLC 17 and a tundish down / down controller 18 for controlling the up and down height of the tundish 3 according to the output value of the DCS 16.

In addition, the position detector 14 has a flow ring 20 is formed on the upper portion to absorb the left and right vibration of the position detector 14.

And the immersion depth control method of the immersion nozzle of the present invention measures the vertical movement distance of the tundish (3) with the position detector 14, and detects the mold level with the mold level detector (15) to determine the equipment constant for each tundish car The depth of immersion of the immersion nozzle 6 is calculated for each strand using a level 1 computer (DCS) 16, and then the turn of the tundish PLC (17) and the turn according to the calculated immersion depth of the immersion nozzle (6). The dish up / down controller 18 controls the up and down movement of the tundish to control the deposition depth of the deposition nozzle.

In addition, the immersion depth of the immersion nozzle 6 can be arbitrarily adjusted by the operator looking at the indicators (11), (12), (13) according to the pattern by steel type width and other operating conditions.

Hereinafter, with reference to the accompanying drawings will be described in detail the operation and effect of the present invention.

1 is a cross-sectional view of a tundish provided with an indicator and a position detector according to the invention, FIG. 2 is a configuration diagram of an apparatus for controlling depth of immersion of the present invention, and FIG. 3 is a structural diagram of a position detector according to the present invention. Figure 5 is a view for explaining the immersion depth calculation method of the immersion nozzle according to the present invention, Figure 5 is a flow chart of the operation of the immersion depth control device of the immersion nozzle of the present invention, the method for measuring the immersion depth of the immersion nozzle (6) The mold cover at the lower part of the tundish (3) when the tundish (3) is lowered to the lowest level as two factors that determine the immersion depth of (6), that is, the mold bath surface level and the tundish (3) up and down height and equipment deviation. (Mould Cover) This is calculated using the length to the top and the length of the deposition nozzle 6 itself (to the top of the discharge port).

By the way, the up and down height measurement of the tundish (3) can be obtained by measuring the amount of rotation of the tundish drive motor (4), but the tundish that can accommodate the volume to be expanded by the motor needs to be modified Due to the lack of space in the car, the present invention installs a rod type position detector 14 to detect the position of the tundish 3 and the installation position is a tundish car for seating the tundish 3. The sensor of the position detector 14 is fixedly installed at a fixed portion of the tundish car fixing part 2 to measure the vertical operating distance of the tundish 3.

As shown in FIGS. 1 and 2, the position detector 14 is positioned perpendicular to the moving direction of the tundish car, and the moving part 1 of the upper part of the tundish car is connected to the fixing part 2 of the lower part. If the moving part 1 of the upper portion of the tundish car is slipped in the advancing direction of the tundish 3 while the upper contact surface 19 is not fixed but only contacts, the sensor itself of the position detector 14 may be damaged. Can be. In order to prevent such sensor breakage, the left and right vibrations of the position detector 14 may be absorbed, and in order to prepare for the occurrence of front and rear flow, the upper portion of the position detector 14 may have a flow ring 20 as shown in FIG. As shown in FIG. 2, a control device for correcting the difference in the positional deviation of the tundish 3, which is restored at the end of the flow of the tundish 3, depends on the degree of deterioration of the tundish car. Is composed.

The hardware constituting such a device includes the above-described position detectors 14 and indicators 11, 12, and 13, as well as a converter and an analog output card (not shown) in a tundish car. 14) Use a high measurement accuracy (within ± 2mm), and install a protective film on the moving part to prevent the inflow of foreign substances such as dust. The apparatus further includes a DCS (Level 1 computer) 16 which calculates the immersion depth value of the immersion nozzle 6 by receiving the position detection value and the mold level value of the position detector 14, and performs deviation control with respect to the initial position of casting. It also has a tundish PLC.

Each computer shown in FIG. 2 is a computer that can instruct a standardized operation according to a simple one-dimensional numerical calculation and conditions, and is commercialized in a steel mill factory. The immersion depth value of the immersion nozzle 6, which is configured to transmit every second and is calculated at the same time, is linked to the upper level process computer (level 2 computer). , Minimum). This value is again connected to the FDDI network and finally stored together in a central data server that stores information on the degree and extent of defects on semi-finished and final products. The time required for transmission can be said to coincide with the occurrence of an event, and the completion time of the final product correction process is related to the delivery date of the product.

Such a central computer allows a user to analyze the quality influence of the operator by using a statistical analysis tool (Tool) for quality evaluation of the product, and standardizes the immersion depth value of the immersion nozzle (6).

The immersion depth value of the immersion nozzle 6 calculated as described above is calculated by using the position detection value and the facility constant value of the molten steel inside the mold 5 by the pre-installed mold level detector 15. That is, as shown in FIG. 4, the immersion depth D of the deposition nozzle is calculated by Equation 1 below.

[Equation 1]

D = A-B-C

Where A is the distance from the bottom of the tundish to the top of the discharge port of the deposition nozzle, B is the distance from the bottom of the tundish to the top of the mold, and C is the distance from the hot water surface of the molten steel to the top of the mold.

The immersion depth value of the immersion nozzle 6 measured during casting is transmitted to each upper level computer. Finally, the last operator correlates the defect with the appropriate immersion depth for each casting condition based on the preset product unit performance and defect occurrence performance. Through analysis, it is possible to standardize the appropriate deposition depth criteria for each steel type.

The initial casting operation is the level 0 of the water level in the mold 5 at the point of time when the PLC receives the autocomming signal (AUTOCOMMING signal) from the existing system where the position of the tundish car is automatically set to the casting position. The tundish is lowered to the set immersion depth set on the basis of the standard, and the operator can manually operate it if necessary, and it is possible to control different reference values according to the pattern according to the width and other operation conditions by steel type, thus eliminating the need for separate understanding of the standard. The management of the pattern can be performed by the DCS 16. Deviation control against the target value during casting is not controlled because the motor overload is expected due to the slow speed of the target value and excessive movement of the up and down tundish, and the indicators (11), (12), and (13) are not necessary. Unauthorized operation can be prevented by allowing reporters to make arbitrary adjustments. When the immersion depth error of the immersion nozzle 6 due to the deformation of the tundish car itself occurred, Equation 1 for calculating the immersion depth was corrected by the correction value, in which case the direct immersion nozzle 6 was Although it is necessary to follow the existing method of collecting and measuring, it can be regarded as semi-permanent correction value because the occurrence of tundish deterioration is changed over the long term by the device deformation of the tundish car itself. There may be a difference, but it is not a problem because it is possible to input the correction value for each car number (equipment deviation).

In other words, if there is an accurate input of the initial value at the time of configuration of the device, further modification is rarely necessary.

The immersion depth value of the immersion nozzle 6 can be monitored continuously by the position of the operator during the casting, that is, by the indicator located on the mold side part, and can be monitored on the upper part of the panel even when the manual operation by the local panel (LOCAL PANEL) is performed. By the indication, the operator's convenience was improved.

The configuration of the device for analyzing the quality impact of the product is applied to the device that predicts the degree of deterioration of quality according to the size of the deviation value compared to the immersion depth reference value of the immersion nozzle (6). In addition, the device is configured so as to standardize the depth of immersion by verifying the feasibility of setting the depth of immersion nozzle 6 through the evaluation of flaw defects and analysis of product unit defects. Accordingly, the control device is configured to lower the immersion depth value of the initial casting immersion nozzle 6 to a set value and feed back control, thereby contributing to the reduction of defects through standardization.

The quality evaluation device of the product using the immersion depth value of the immersion nozzle 6 is made by the interaction between the process computer (level 2 computer) and the central computer that manages the defect prediction standard and the defect tolerance standard. When the device is not running, it is possible to analyze the influence of quality against the immersion depth actual value that is expected to take excessive time within a short time with the operation of this quality evaluation device, and the casting time per cast is usually 7 to 8 minutes. When the trend of immersion depth change trend (TREND) is necessary for time, micro-determination of trend is possible through the data server of the central computer that stores the actual results in seconds for 3 months.

The present invention, which works as described above, continuously generates accurate and rapid measurement of elements directly affecting the generation and distribution of intervening defects occurring during the solidification of molten steel in a mold. It is possible to utilize the immersion depth of the immersion nozzle measured in the standardization work to minimize the distribution and amount of impurities, and to reduce the possibility of deviation between operators by automating the immersion depth set operation of the immersion nozzle. Automatic continuous operation has the advantage of improving work efficiency.

Claims (4)

The tundish moving part (1) and the tundish holding part (2), the tundish (3), the driving motor (4), the mold (5), the immersion nozzle (6), the tundish moving wheel (7), and the local panel ( 8) In the performance equipment provided with a piston 9 and a long nozzle 10, the indicators 11, respectively installed on the upper portion of the local panel 8 and the upper peripheral edge of the tundish 3; 12), 13, the position detector 14 for detecting the up-down position of the tundish 3, the mold level detector 15 for detecting the mold level, the position detection value of the position detector 14 and the mold DCS (level 1 computer) 16 which calculates and outputs the immersion depth of the deposition nozzle 7 by inputting the mold level value of the level detector 15, and the image of the tundish 3 according to the output value of the DCS 16. Immersion depth control device of the deposition nozzle, characterized in that consisting of a tundish PLC (17) and a tundish up / down controller (18) for controlling the height of the lower. The apparatus of claim 1, wherein the position detector (14) has a flow ring (20) formed thereon to absorb the left and right vibrations of the position detector (14). The position detector 14 measures the moving distance of the tundish 3 up and down, the mold level detector 15 detects the mold level, corrects the equipment constant for each tundish car, and level 1 computer (DCS) 16. The depth of deposition of the immersion nozzle 6 is calculated for each strand and then tundished with the tundish PLC 17 and the tundish up / down controller 18 according to the calculated depth of immersion nozzle 6. Immersion depth control method of the immersion nozzle, characterized in that to control the immersion depth of the immersion nozzle by controlling the vertical movement of the. The immersion depth of the immersion nozzle (6) according to claim 3, wherein the immersion depth of the immersion nozzle (6) can be arbitrarily adjusted by the operator looking at the indicators (11), (12), (13) according to the width and other operating conditions-specific patterns How to control the immersion depth of the nozzle.