JPS6383625A - Method for measuring temperature of high temperature object - Google Patents

Abstract

PURPOSE:To attain the continuous measurement of an average temperature with high responsiveness, by performing the temperature measurement of a high temperature object to be measured, for the measurement of the propagating time of an ultrasonic wave emitted from an ultrasonic wave transmitting/receiving element, and a temperature-sound speed characteristic in a molten metal. CONSTITUTION:Ultrasonic coupling bars 3 and 4 interposing a molten metal 2 in a vessel 1 are manufactured of a heat resistant material, etc. Each one end of the bars 3 and 4 is brought into contact with the molten metal 2, and the ultrasonic wave transmitting/receiving elements 5 and 6 mounted on the other ends are connected to an ultrasonic wave transmitter/ receiver 7. At this time, when the ultrasonic wave is transmitted from the element 5, a part of it is reflected on an end face 3-1, and is received by the element 5, and the propagating time in the bar 3 is recognized by the timer of the transmitter/receiver 7. A part of the ultrasonic wave is received by the element 6 through the end face 3-1, the molten metal 2, and the bar 4, and the propagating time during that time can be obtained. Furthermore, when the ultrasonic wave is transmitted from the element 6, the respective required times can be obtained similarly. A computing element 7 measures the average temperature continuously from the propagating time of the ultrasonic wave in the molten metal obtained by a prescribed equation, and the stored temperature-sound speed characteristic of the molten metal 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring the temperature of a high-temperature object, such as molten metal, and for measuring the average temperature of molten steel contained, for example, in a tundish in a converter or continuous casting equipment. This invention relates to a temperature measurement method suitable for continuous measurement of temperature.

[Conventional technology]

It is generally known that in blowing operations in a converter furnace, managing and controlling the temperature of molten steel in the furnace in real time is an important requirement for adjusting the blowing temperature. In addition, in cases where steel is continuously cast, a tundish is used as an intermediate container between the casting pot and the mold, and the casting conditions include accurately controlling the temperature of the molten steel in the tundish.
It is generally known that this is an important requirement that determines the casting work and the properties of the finished slab.
Therefore, various efforts have been made in the past to strictly perform such temperature control.

That is, conventional methods for measuring the temperature of molten steel include the spot temperature measurement method using a consumable thermocouple, or, for example, the method disclosed in Japanese Patent Application Laid-open No. 1986-
11329, there are continuous thermostats with built-in thermocouples in the protective tube, but all of them have drawbacks.

[Problem that the invention seeks to solve]

The spot temperature measurement method is a commonly used method, but in this method, the measurer immerses a consumable thermocouple in molten steel, so the temperature measurement is spot-time.
In addition, the measurement variation is large depending on the immersion position, and the average temperature in molten steel cannot be measured. Moreover, a consumable thermocouple is consumed for each measurement, increasing running costs.

In addition, in the continuous temperature measurement method in which a thermocouple is built into a protection tube, the thermocouple protection tube is expensive and easily damaged, resulting in a considerable increase in running costs. There is a time lag in measurement. Also, like consumable thermocouples, the average temperature in molten steel cannot be measured.

The present invention provides a method for accurately, responsively and continuously increasing the average temperature of a hot object, such as a molten metal.

[Means for solving problems]

The present invention will be described in detail as an example of temperature measurement of molten metal with reference to the drawings.

In the drawings, particularly in FIG. 1, 1 is a container, and 2 is molten metal, such as molten steel, contained in the container 1.

Reference numeral 3.4 denotes an ultrasonic coupling rod, which is provided facing each other with the molten metal 2 in the container 1 interposed therebetween. The ultrasonic coupling rods 3 and 4 are made of a heat-resistant material that is resistant to melting damage against molten steel and other molten metals, and has slag resistance and spalling resistance in cases where slag is present, and at the same time has ultrasonic propagation performance. Or made of refractory material (can be metal or non-metallic). The ultrasonic coupling rods 3 and 4 are used to enable ultrasonic transmission and reception between the high-temperature molten metal 2 and the molten metal 2 using ultrasonic transmitting and receiving elements with low heat resistance, and one end is in contact with the molten metal 2. , ultrasonic transmitting and receiving elements 5 and 6 are attached to the other end.

These ultrasonic transceiver elements 5 and 6 are electrically connected to an ultrasonic transceiver 7, and are capable of both transmitting and receiving ultrasonic waves. For example, when an ultrasonic wave is transmitted from the ultrasonic transmitting/receiving element 5, a part of the ultrasonic wave is reflected by the end face 3-1 of the ultrasonic coupling rod 3 and is received by the ultrasonic transmitting/receiving element 5, and half of the elapsed time t1 during this period is The time required for propagation in the acoustic wave coupling rod 3 is t2. This propagation time t2 is the ultrasonic transceiver 7
This is determined by the timer installed in the.

A part of the ultrasonic wave propagates through the end face 3-1, the molten metal 2, and the other ultrasonic coupling rod 4, and is received by the ultrasonic transmitting/receiving element 6.
The required propagation time t3 during this period is obtained.

Further, when an ultrasonic wave is transmitted from the ultrasonic transmitting/receiving element 6, a portion of the ultrasonic wave is reflected by one end 4-1 of the ultrasonic coupling rod 4, as described above.
It is received by the ultrasonic transmitting/receiving element 6, and the elapsed time t4 during this time
half of the time required for propagation in the ultrasonic coupling rod 4.

Therefore, the time t required for ultrasonic propagation in molten metal is t =
t 3-t 2-t 5 ・・・・・・
(3) can be easily obtained. That is, the ultrasonic coupling rod 3
When measuring the ultrasonic propagation time in the molten metal 2 using the ultrasonic transmitter/receiver element 5.6, the propagation time in the ultrasonic coupling rod changes depending on the temperature change of the ultrasonic coupling rods 3 and 4. measures the time required for the ultrasonic wave to propagate through the coupling rod in real time as described above, and inputs this to the calculator 8.

The computing unit 8 is a computing unit that computes equations (1) to (4), stores temperature-sound velocity characteristics as shown in FIG. 3, and outputs the temperature. The arithmetic unit 8 calculates the above (11(2)
) (By calculating using Equation 31, the ultrasonic propagation time in the molten metal can be accurately determined.

Here, if the length between the end surfaces 3-1.4-1 of the ultrasonic coupling rods 3 and 4 is kept constant, the average sonic velocity dust V in the molten metal existing between the end surfaces 3-1.4-1 is is required.

However, the average sound speed of most molten metals 2 is between -0.2 and -0.
, 6m/s/''C. This varies depending on the type of molten metal 2 and the temperature range, but since the temperature-sound velocity characteristics of the target molten metal 2 are stored in advance,
The average temperature of the molten metal 2 can be continuously measured from the average sonic velocity dust (2) in equation (4). In addition, in terms of measurement response, extremely fast measurements are possible because only the sound waves are propagated through the substance to be measured.

Note that 9.10 is a water-cooled box for preventing heat from being transmitted to the ultrasonic transmitting and receiving elements 5 and 6 through the ultrasonic coupling rods 3 and 4.

The molten metal 2 whose temperature is measured may be not only molten steel but also other molten metals, and the present invention is also applicable to these. Further, it can be similarly adopted for molten liquid high temperature slabs and the like.

Further, the ultrasonic coupling rods 3.4 can be installed vertically facing each other as shown in FIG.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to measure the average temperature of a high-temperature object continuously and with extremely fast response, which is extremely effective industrially.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention, Fig. 2 is an explanatory diagram showing another embodiment of the invention, and Fig. 3 is a temperature-sound velocity characteristic of a high temperature object to be measured, which is stored in advance in a computing unit. This is a chart showing an example. 1: Container, 2: High temperature object, 3.4: Ultrasonic coupling rod,
5.6: Ultrasonic transceiver element, 7: B sonic transceiver,
8; Computing unit applicant Minoru Aoyagi, patent attorney representing Nippon Steel Corporation Figure 1 Figure 2 Temperature (0C) Figure 3

Claims (1)

[Claims] Ultrasonic waves are emitted from ultrasonic transmitting/receiving elements installed between the high-temperature object and the high-temperature object via ultrasonic coupling rods, and the propagation time in the high-temperature object is measured. A method for measuring the temperature of a high-temperature object, comprising measuring the average temperature of the high-temperature object based on the length between the ultrasonic coupling rods of the object and a temperature-sound velocity characteristic stored in advance.