JPS6080720A - Measuring method of amount of molten metal - Google Patents

Abstract

PURPOSE:To reduce an installation cost without marring precision of a titled measuring method by catching optically the boundary of immersed part and nonimmersed part of a metallic rod for detecting a height of molten metal surface which is immersed in the molten metal in a vessel and is pulled up therefrom, and obtaining the height of said metal surface. CONSTITUTION:A holder 5 supporting a round-steel rod 6 for detecting a height of molten steel surface above a ladle 2 stored a molten steel 3 is connected with a drum 7 driven by a motor 8 via a wire, and the pulse of a pulse generator 9 fitted to the drum 7 is supplied to a counter 12. Furthermore, an image sensor 10 is arranged in the ascent and descent ragne of the rod 6 to detect a bright part of high temp. immersed in the molten steel 3, and a detection signal of the bright part is outputted to an arithmetic circuit 13 and a timer 15 via a control part 11. By said method, the height from the molten steel surface up to the detection position of the bright part of the rod 6 is obtained by the counted value of the counter 12, and the height of the molten steel surface is calculated by the circuit 13, furthermore the amount of molten steel is calculated to display said amount on a display device 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for determining the amount of molten metal by detecting the molten metal scene height within a vessel.

The method for measuring the weight of molten steel in the ladle is to place the ladle 2 on a weighing machine 20 installed on the steel receiving cart 1 as shown in Fig. 1, measure the total weight of the ladle, and calculate the total weight of the ladle from this measured value. The most common method is to subtract the ladle weight.

In this case, there is no problem with the measurement technique, but equipment such as a weighing machine is expensive and its maintenance is somewhat difficult.

For this reason, various reports and proposals have been made on measurement methods that utilize the differences in the physical properties of the self-melting steel in the ladle and the slag that floats on top of it, as a method that requires low equipment costs and is easy to maintain.

These methods detect the molten steel level in the ladle, that is, the height of the molten steel surface, and measure the weight of molten steel based on the ladle condition at that time, the specific gravity of the molten steel, etc. There are methods that use the electrical resistance difference and temperature difference between the slag and molten steel, or change the impedance between the slag and molten steel using an eddy current coil. However, in these cases, the reproducibility of the /8 steel scene height detection value is poor, and therefore the measurement error of the molten steel weight is large.

The present invention has been made in view of the above circumstances, and its purpose is to provide a method for measuring the amount of molten metal in a container that has good reproducibility, is inexpensive in equipment cost, and is easy to maintain.

The method for measuring the amount of molten metal according to the present invention is a method of measuring the amount of molten metal by detecting the height of the molten metal in a container, in which a metal surface height detection rod is immersed in the molten metal in the container from above. The boundary between the molten metal immersed part and the non-molten metal immersed part of the detection rod is optically captured, and the scene height is calculated based on the height at which the detection rod is pulled up when the detection rod is captured. It is characterized by measuring the amount of molten metal from the content per unit height of the molten metal.

The present invention will be explained below based on the drawings. FIG. 2 is a schematic diagram showing the implementation state of the present invention, and 2 in the figure shows a ladle placed on the steel receiving truck 1. Molten steel 3 is stored in the ladle 2, and slag 4 with a small specific gravity is floating above it.

A detection rod 6 for detecting the height of the molten steel of round steel is supported by a holder 5 above the ladle 2, and the holder 5 is connected via a wire to a drum 7 for winding the wire, and the drum 7 can be moved up and down. The boulder 5 is rotated by the drive of the motor 8.
and raises and lowers the detection rod 6. A hals generator 9 is attached to the drum 7, and the pulse generator 9 emits pulses according to the rotation angle of the drum 7,
Send to 2. As a result, the amount of rotation of the drum 7 and the detection KS6
It is possible to measure the lifting and lowering position of the A horizontally arranged one-dimensional image sensor 0 is installed at a position facing the elevation area of the detection rod 6.

The output signal from the image sensor 10 is given to the control unit 11, and the control unit 11 outputs a bright area detection signal to the arithmetic circuit 13 and the timer 15 when the image sensor 1o detects a bright area. On the other hand, the counter 12 is manually reset when the detection rod 6 is immersed in molten steel, and counts the number of pulses sent from the pulse generator 9 when the detection rod 6 is raised. When the bright area detection signal is input, the arithmetic circuit 13 takes in the counted value from the counter 12, calculates the /8 steel scene height from the taken counted value based on a preset formula, and further calculates the weight of molten steel. The calculated value is displayed on the display 14. The timer 15 starts operating when a signal is input from the control section 11, and stops the lifting motor 8 after a predetermined period of time has elapsed.

Next, the measurement details of the present invention will be explained based on the flowchart shown in FIG. A ladle 2 storing molten steel 3 to be measured is placed on a steel receiving truck 1 and transported. The steel receiving cart 1 stops when it reaches a predetermined position. An unused detection rod 6 attached to a holder 5 in advance is suspended above the ladle 2.

When preparations for measurement are completed, the operator drives the lift motor 8 to lower the detection rod 6, and when the lower end of the detection rod 6 is immersed in the molten steel 3, the operator stops the lift motor 8.

At this time, the counter 12 is reset to zero. After a predetermined period of time has elapsed, the operator drives the lifting motor 8 to raise the detection rod 6. The counter 12 counts the pulse signals sent from the pulse generator 9.

The part of the lower end of the detection rod 6 that is immersed in the molten steel 3 has solidified high-temperature base metal adhering to it, and the base metal part is red.

In contrast, the area immersed in the slag is dark. Therefore, when the detection rod 6 is pushed upward and the upper end of the bare metal, which becomes red or bright, is sensed by the image sensor 10, the image sensor 10 gives its output signal to the control section 11. Control unit 11
outputs a bright area detection signal based on the input signal and sends it to the arithmetic circuit 13 and timer 15. When the arithmetic circuit 13 receives the bright area detection signal, the arithmetic circuit 13 takes in the counted value from the counter 12 when it is manually operated. This count value is measured by the detection rod 6 from the molten metal surface.
This is a numerical value representing the height (hx) to the bright area detection position.

The following formulas (11 and f21) are preset in the arithmetic circuit 13 to obtain the molten steel scene height h and the molten steel type 1w, respectively.

h=H, -hx...(1) However, Ho: Height from the bottom of the ladle to the detection position of the image sensor W-ρ・h・CV (h)+α]...(2) However, ρ 2l'8 Steel density v (h) : Ladle content per unit height of each ladle α : Ladle content increase value per unit height determined by the number of times the ladle is used Note that the molten steel density ρ is I Temperature measurement value Use the value corrected by the type of steel receiving steel. V (h) is the inside shape of the ladle, where the top is wider than the bottom. This is a function in which the scene height h used as a variable is used to accurately express it.Also, α is a value for correcting V (h) since the ladle will melt and wear out depending on the number of times it is used.

The arithmetic circuit 13 calculates the molten steel scene height h using the count value taken in from the counter 12 and the fl1 formula, and calculates the height h of the molten steel surface,
The weight of molten steel is calculated using the formula (2), the ladle number, the number of times the ladle is used, the measured value of the receiving steel temperature, and the receiving W4 steel type, and the calculation result is displayed on the display 14.

On the other hand, the timer 15 starts operating when a bright area detection signal is input from the control section 11, and after a predetermined period of time has elapsed, the lifting motor 8 is stopped and the holder 5 and the detection rod 6 are returned to a predetermined position.

In addition, although the above description shows the case of FG steel, the present invention is of course not limited to this, and can be carried out similarly even when using other molten metals, especially molten pig iron.

Next, the effects of the present invention will be explained. First, regarding reproducibility, the steel receiving cart 1 is moved to measure the same /8 steel 3 in the ladle 2 10 times, and the molten steel scene height is We measured the

FIG. 4 shows the measurement results, with the horizontal axis representing the number of measurements (times) and the vertical axis representing the height of the molten steel (fl ). From this figure, in the case of the present invention, the measurement error of the f4 steel scene height is ±251'm with respect to the molten steel scene height of about 2500 m.
It was found that the reproducibility was good.

Furthermore, the error between the /g steel weight calculated by the present invention and that actually measured using a weighing machine was determined by measuring the gravity of molten steel in the ladle for 10 charges. Note that the melting temperature was 1680 to 1730°C.

Figure 5 shows the measured weight (T) on the horizontal axis and the calculated weight (T) on the vertical axis.
This is a graph showing the measurement results of T), and the solid line in the figure represents the case where there is no error between the measured weight and the calculated weight. From this figure, it can be seen that the measurement error in the calculated weight according to the present invention is within ±200 kg with respect to the measured weight (approximately 70T), which indicates that the measurement accuracy is extremely high.

Therefore, the molten steel weight calculated by the present invention has little error,
Therefore, when casting an ingot using the ingot casting method, the weight of the molten steel in the ladle can be calculated accurately, so there is no shortage of hot water.Also, even when using the continuous casting method, the weight of the molten steel can be accurately calculated, so the weight of the molten steel inside the tundish can be accurately calculated. It is possible to prevent slag from flowing out when pouring molten steel into the molten steel, thereby making it possible to stably carry out the operation of the next process, and also to prevent quality deterioration due to slag.

In the case of the present invention, repeated and accurate measurements are possible by replacing the detection rod, and maintenance is easy.

As detailed above, the present invention measures the weight of molten metal with less measurement error because the detection rod is immersed in molten metal and pulled up, and the adhering metal is optically captured to determine the height of the molten metal. Therefore, excellent effects such as stable operation in the next process and prevention of quality deterioration are achieved.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the measurement contents of the conventional method, Fig. 2 is a schematic diagram showing the implementation state of the method of the present invention, Fig. 3 is a flowchart showing the measurement contents of the present invention, Figs. Figure 5 is a graph showing the effects of the present invention. 2... Ladle 3... F4 & ¥4 6... Molten steel level height detection rod lO... Image sensor patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono

Claims (1)

[Claims] 1. In the method of measuring the amount of molten metal by detecting the height of the molten metal in the container, a metal height detection rod is dipped into the molten metal in the container from above and pulled up, and the molten metal on the detection rod is measured. The boundary between the immersed metal part and the non-molten metal immersed part is optically captured, the scene height is determined based on the height at which the detection rod is pulled up when the boundary is captured, and the scene height and the content per unit height of the container are calculated. A method for measuring the amount of molten metal in a container, the method comprising: measuring the amount of molten metal in a container.