JP2006064444A - Method of measuring flow velocity of molten metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring correctly a flow rate of a surface of molten steel in casting mold of, e.g. continuous casting facility. <P>SOLUTION: For measuring the flow rate, pressure received by a pressure receiving rod immersed into molten metal is received by two strain gauges fixed at a position perpendicular to each other separated into two components. In addition, for a electromagnetic flow meter, a pair of strain gauges are fixed at a position perpendicular to each other for detecting the pressure to be received by a magnet or a coil separately in two components. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molten metal flow velocity measurement method suitable for measuring the surface flow velocity of molten steel in a mold in a continuous casting facility for steelmaking, for example. In addition, below, it demonstrates for the molten steel which is a typical example of a molten metal.

As a method for measuring the molten steel surface flow velocity in the mold in the conventional continuous casting equipment, a method is generally used in which a pressure-receiving rod made of refractory is immersed in molten steel and the pressure applied to the pressure-receiving rod is measured ( For example, see Patent Document 1).
In addition, as a non-contact measurement method, a method of using a permanent magnet or generating a DC magnetic field in an electromagnetic coil is described in Patent Document 2, and a method of generating an AC magnetic field using an electromagnetic coil is described in Patent Document 3. Each is listed.
Japanese Patent Laid-Open No. 4-178525 JP-A-7-181195 JP-A-9-33554

  Now, the detection of the force generated from the conventional fluid, that is, the pressure when immersing the pressure-receiving rod and the Lorentz force when using a permanent magnet or electromagnetic coil, is usually performed using a strain gauge. It is. For example, the method for measuring the flow velocity of molten steel is to attach a strain gauge to a metal thin plate that is integrated with the detection site (a pressure receiving rod for detecting pressure and a magnetic material for detecting Lorentz force). The flow rate signal is obtained by measuring the generated strain with this strain gauge. However, since the actual molten steel flow is a vector quantity having a size and a direction, the measurement is limited to the flow velocity component in the direction perpendicular to the metal thin plate, and there is a disadvantage that high-precision measurement cannot be expected.

  An object of the present invention is to solve the above problems and provide a method for accurately measuring the flow velocity of the molten steel surface in a mold of a continuous casting facility, for example.

  In order to solve the above-mentioned problems, the present invention uses two strain gauges for detecting pressure or Lorentz force, and attaches them at positions orthogonal to each other, thereby separating the flow velocity signal into two components and measuring accurately. It is something that can be done.

That is, the gist of the present invention is as follows.
(1) When detecting the pressure received by the pressure receiving rod immersed in the molten metal and measuring the flow velocity of the molten metal, two strain gauges are attached to the pressure receiving rod at positions orthogonal to each other, and the pressure received by the pressure receiving rod is measured. A method for measuring a flow rate of molten metal, characterized by separating and detecting two components.

(2) The electromagnetic force received from the molten metal flow is detected through a permanent magnet or an electromagnetic coil, and when measuring the flow velocity of the molten metal, the two strain gauges are placed at positions orthogonal to each other on the permanent magnet or the electromagnetic coil. A method for measuring a flow rate of molten metal, characterized in that a Lorentz force generated in an attachment, permanent magnet or electromagnetic coil is separated into two components and detected.

  In the present invention, the flow rate of molten steel can be measured as a two-dimensional vector value by detecting the force generated by the molten steel flow with two strain gauges arranged orthogonal to each other. Therefore, it becomes possible to measure the flow rate of molten steel more accurately than before.

Next, the method of the present invention will be described in detail with reference to the drawings.
First, the application of the present invention will be described with reference to FIG. 1 in the case where the flow of molten steel is detected by a pressure receiving rod immersed in the molten steel. That is, the arrow indicated by reference numeral 1 indicates the flowing direction of the molten steel. The pressure receiving rod 2 immersed in the flowing molten steel is provided with two thin metal plates 3 integrally, and each thin metal plate 3 is provided with a strain sensor 4x and 4y is attached. Here, by providing the two thin metal plates 3 in directions orthogonal to each other, the directions of the strain sensors 4x and 4y are set to be in an orthogonal relationship. By arranging the strain sensors 4x and 4y in this way, the pressure received by the pressure receiving rod 2 due to the flow of molten steel is measured as the x component by the strain sensor 4x, and the y component in the direction orthogonal to the x component is the strain sensor. It can be measured at 4y.

  Next, the application of the present invention will be described with reference to FIG. 2 in the case where the flow of molten steel is detected by a permanent magnet or an electromagnetic coil. The permanent magnet 5 arranged in a non-contact manner with respect to the molten steel flowing in the direction of the arrow 1 is integrally provided with a flexible cylinder 6 made of resin, for example, and strain sensors 4x and 4y are attached to the cylinder 6. is there. Each of the strain sensors 4x and 4y is a sensor of a type in which two sensors attached at opposing positions spaced apart by 180 ° on the same circumference of the cylinder 6 are set as a pair, and the strain sensors 4x are arranged so that the opposing directions are orthogonal to each other. And 4y are adjusted. By arranging the strain sensors 4x and 4y in this way, the Lorentz force generated in the permanent magnet 5 by the molten steel flow and transmitted to the cylinder 6 is measured by the strain sensor 4x as the x component, and the direction orthogonal to the x component is measured. The y component can be measured by the strain sensor 4y.

  According to the present invention, the flow rate of molten steel can be measured as a vector value by detecting the force generated by the molten steel flow with two strain gauges attached at positions orthogonal to 90 degrees. Therefore, a plurality of sensors by the pressure receiving rods are arranged in, for example, a continuous casting mold to measure the flow velocity, or the Lorentz force generated in the magnetic material is measured at different locations outside the continuous casting mold, for example. By performing it a plurality of times, it becomes possible to accurately measure the molten steel flow velocity distribution in the continuous casting mold.

As shown in FIG. 3, continuous casting was performed in a mold having a size of 260 mm × 1700 mm during casting using molten steel having a superheat degree (difference between molten steel temperature and solidification temperature) of 35 ° C. in the tundish. .
Here, in FIG. 3, 11 is a tundish, 12 is molten steel, 13 is a tundish elevating device, 14 is a sliding plate, 15 is an immersion nozzle, 16 is a mold, 17 is a flow control device (electromagnetic) that controls the flow of molten steel in the mold. Brake). The molten steel 12 in the tundish 11 is injected into the mold 16 from the sliding plate 14 via the immersion nozzle 15.

  In this continuous casting, as shown in FIG. 4, the distance between the short sides of the mold, that is, 1/4 position from the short side inner wall of the full width W of the mold (intermediate between the immersion nozzle 15 and the short side inner wall) is shown in FIG. The pressure receiving rod 2 shown was immersed at a depth of 50 mm, and the flow rate of the molten steel was measured by the strain sensors 4x and 4y.

  Here, the conversion of the flow velocity from the strain sensor signal was performed using a calibration curve created using a water model.

  As shown in FIG. 3, continuous casting was performed in a mold having a size of 260 mm × 1700 mm during casting using molten steel having a superheat degree (difference between molten steel temperature and solidification temperature) in the tundish of 35 ° C. .

  In this continuous casting, as shown in FIG. 3, the permanent magnet 5 shown in FIG. 2 is attached to the base 18 installed outside the mold via the arm 19, and the permanent magnet 5 is arranged as shown in FIG. Then, the flow rate of the molten steel was measured by the strain sensors 4x and 4y.

  Here, the relationship between the signal of the strain sensor and the flow velocity was derived using a calibration curve created by experiments using a low melting point metal. The force generated in the permanent magnet is proportional to the electrical conductivity of the fluid and can be corrected.

It is a figure which shows the measuring point by a pressure. It is a figure which shows the measuring point by Lorentz force. It is sectional drawing which shows the outline of the casting_mold | template vicinity of a continuous casting installation. It is a figure which shows arrangement | positioning of a pressure receiving rod.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flow direction of molten steel 2 Pressure receiving rod 3 Metal thin plate 4x, 4y Strain gauge 5 Permanent magnet 6 Resin cylinder

Claims (2)

  When measuring the pressure received by the pressure receiving rod immersed in the molten metal and measuring the flow velocity of the molten metal, two strain gauges are attached to the pressure receiving rod at positions orthogonal to each other, and the pressure received by the pressure receiving rod is divided into two components. A method for measuring a flow rate of molten metal, characterized by separating and detecting.   The electromagnetic force received from the molten metal flow is detected through a permanent magnet or an electromagnetic coil, and when measuring the flow velocity of the molten metal, two strain gauges are attached to the permanent magnet or the electromagnetic coil at positions orthogonal to each other. A method for measuring a flow rate of molten metal, comprising: detecting a Lorentz force generated in a magnet or an electromagnetic coil by separating it into two components.

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