WO2016016967A1 - 溶融金属の湯面上に浮遊するスラグの厚さ測定方法 - Google Patents
溶融金属の湯面上に浮遊するスラグの厚さ測定方法 Download PDFInfo
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- WO2016016967A1 WO2016016967A1 PCT/JP2014/070079 JP2014070079W WO2016016967A1 WO 2016016967 A1 WO2016016967 A1 WO 2016016967A1 JP 2014070079 W JP2014070079 W JP 2014070079W WO 2016016967 A1 WO2016016967 A1 WO 2016016967A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B15/00—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons
- G01B15/02—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons for measuring thickness
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- the present invention relates to a method for measuring the thickness of a slag floating on a molten metal surface, and in particular, even when the slag thickness is thin, the thickness can be continuously measured with high accuracy. And a slag thickness measuring method.
- molten steel is poured into a water-cooled mold and cooled by bringing it into contact with the mold, thereby producing a slab by continuously drawing it below the mold while forming a solidified shell.
- the molten steel is temporarily stored, and the tundish is used as an intermediate container between the ladle and the mold for the purpose of distributing the molten steel to a plurality of molds. Is used.
- the slag in the ladle floating on the molten steel surface in the ladle may slightly flow out of the ladle from the ladle into the tundish. is there.
- the slag in the ladle that has flowed into the tundish diffuses into the molten steel in the tundish, and then most of the slag floats on the molten steel and separates from the molten steel, forming a layer on the molten steel surface in the tundish Floating as slag in the tundish.
- the tundish is supplied with flux for the purpose of covering the molten steel in the tundish.
- the flux is melted by the heat of the molten steel to become slag.
- Some slag that cannot float to the upper part of the molten steel is brought into the water-cooled mold together with the molten steel by hot water supply through a tundish immersion nozzle, and remains in the slab as non-metallic inclusions after solidification of the molten steel. It becomes a factor causing surface defects and the like. If the amount of slag increases in the tundish, slag will be caught when the ladle is replaced, and more slag will not rise above the molten steel. Quality problems such as quality defects may occur.
- the slag is likely to be caught. For this reason, when the thickness of the slag in the tundish exceeds a predetermined value, the slag is discharged to the outside from the drain hole provided in the upper part of the tundish. This discharge of slag not only causes secondary troubles such as fire due to scattering, but also causes a drop in product yield by partially discharging molten steel.
- the thickness of the slag in the tundish is an important management factor from the viewpoint of preventing breakout due to slag outflow in the mold and improving operational safety and product productivity.
- Patent Document 1 As a method for suppressing the outflow of slag accompanying the supply of molten steel as much as possible, in Patent Document 1, based on the opening signal of the sliding nozzle that injects molten steel in the tundish into the mold and the level signal of the molten steel in the mold, A method for controlling the opening and closing operations of the sliding nozzle has been proposed.
- Patent Document 1 does not measure the amount of slag in the tundish. Therefore, when this method is applied to the supply of molten steel from the ladle to the tundish, the sliding nozzle is closed early during the continuous casting operation from the viewpoint of reliably preventing the slag from flowing out of the ladle. If it will end up, the remaining molten steel in a ladle will increase, and the problem that the yield of molten steel will fall significantly arises.
- the amount of slag in the tundish is managed by the thickness of the slag.
- the operator usually opens a part of the lid on the top of the tundish, inserts a metal measuring rod into the molten steel in the tundish, and determines the thickness of the slag attached to the measuring rod. Measuring.
- the slag in the tundish does not increase suddenly during casting, but the amount of slag in the tundish gradually increases as the number of consecutive casts increases, that is, the number of ladle replacements increases. Therefore, it is essential to measure the slag thickness every time the ladle is replaced.
- the measurement of the slag thickness using a measuring rod is a temporary measurement by the operator's manual operation, which creates a work burden and a large difference in measured values for each operator. The problem is that it cannot be measured.
- grasping the thickness of the slag that floats on the molten steel surface in the ladle is also important for suppressing the outflow of slag to the tundish. Similar to the thickness of the slag in the tundish, the thickness of the slag that has flowed into the ladle from the converter is also measured using a measuring rod inserted manually, which is a burden on the operator. .
- the measurement of the thickness of the slag in the ladle or tundish during the continuous casting operation is performed manually by the operator, resulting in work load generation and measurement accuracy problems. Further, since the inside of the ladle and the inside of the tundish are in a high temperature atmosphere, manual measurement is not preferable for safety. Furthermore, since the lid must be opened when measuring the thickness of the slag in the tundish, there is a problem that the internal quality of the slab deteriorates due to the intrusion of air into the tundish.
- the present invention has been made in view of these problems, and an object thereof is to provide a method capable of measuring the thickness of a slag with high accuracy without depending on an operator.
- the inventors of the present invention have studied to automatically measure the thickness of the slag using a microwave distance meter.
- a microwave rangefinder As the microwave rangefinder, a frequency modulation continuous wave (FMCW) system generally used for measuring distance with high accuracy was used.
- FMCW frequency modulation continuous wave
- the FMCW method is a method of continuously modulating a microwave frequency with a predetermined amplitude and a predetermined period with respect to a predetermined center frequency.
- a microwave is transmitted from the antenna of the microwave distance meter to the measurement object, and the microwave (reflected wave) reflected by the measurement object is received by the same antenna. Since the frequency of the microwave is modulated, the frequency of the reflected wave from the measurement object (reflected wave reflected by the measurement object; the same applies hereinafter) received by the microwave rangefinder and the reflected wave are The frequency of the microwave transmitted from the microwave rangefinder at the time of reception is different.
- the time from when the microwave is transmitted until the reflected wave at the measurement object is received can be calculated.
- a value obtained by multiplying the calculated time by the speed of the microwave in the atmosphere and dividing by 2 is set as the distance from the antenna to the measurement object. That is, the value L (mm) calculated by the following equation (1) is set as the distance from the antenna to the measurement object.
- L c ⁇ t / 2 (1)
- c the velocity of the microwave in the atmosphere (mm / s)
- t calculated from the difference between the frequency of the reflected wave received and the frequency of the microwave transmitted from the microwave rangefinder at the time of reception. Time (s).
- microwave rangefinders are used to measure the level of molten steel in the converter. By using a microwave distance meter, it is possible to continuously measure the distance to the measurement object without depending on the operator. By applying this, it is considered that the thickness of the slag can also be continuously measured. Further, by arranging the antenna in the tundish, it is not necessary to open the tundish lid when measuring the thickness of the slag. In the present invention, calculating (obtaining) A using the measurement result of the microwave rangefinder is sometimes expressed as “measuring A”. In the following, “reflected wave at B” refers to a microwave (reflected wave) reflected by B.
- microwaves are transmitted from the antenna toward the slag floating on the molten steel and molten steel surface, and the reflected wave and slag of the microwave on the molten steel surface are transmitted.
- the reflected wave on the surface is received by the same antenna.
- the difference between the frequency of the received reflected wave and the frequency of the microwave transmitted from the microwave rangefinder at the time of reception is the first time from when the microwave is transmitted to when the reflected wave at the molten steel surface is received.
- the first time and the second time from when the microwave is transmitted to when the reflected wave on the slag surface is received are calculated.
- the microwave is calculated from the above equation (1) and the first time t1 and the second time t2.
- the distance L0 from the antenna to the molten steel surface and the distance L1 from the antenna to the slag surface can be measured.
- a value ⁇ L obtained by subtracting the distance L1 from the distance L0 is considered to be the slag thickness.
- ⁇ L can be expressed by the following equation (2).
- c speed of microwave in the atmosphere (mm / s)
- t1 first time (s)
- t2 second time (s).
- the thickness of the slag floating on the molten steel surface in the tundish is usually in the range of 10 to 20 mm.
- a so-called general-purpose microwave having a center frequency of 20 GHz as a microwave and a frequency modulation amplitude (hereinafter also referred to as “modulation amplitude”) of 4 GHz is used, Since the thickness of the slag in the tundish is too thin, the reflected wave on the molten steel surface and the reflected wave on the slag surface are not separated, and the reflected wave on the slag surface cannot be clearly confirmed, so the slag thickness is measured. I found it impossible. On the other hand, it has been found that by using a microwave having a center frequency of 24 to 32 GHz and a modulation amplitude of 8 to 10 GHz, the thickness can be measured even if the slag is thin.
- the thickness of the slag can be obtained with high accuracy. I found out. Details of the examination will be described later.
- the present invention has been made on the basis of these findings, and the gist thereof lies in the following method for measuring the thickness of slag floating on the molten metal surface.
- a microwave rangefinder that transmits and receives a frequency modulated microwave with a center frequency of 24 to 32 GHz and an amplitude of frequency modulation of 8 to 10 GHz from an antenna, it floats on the molten metal surface.
- a method for measuring a thickness of a slag wherein the microwave rangefinder transmits the microwave from the antenna toward the molten metal and the slag, and the microwave is transmitted from the molten metal surface of the molten metal.
- the reflected wave on the surface of the slag is received by the antenna, and when the frequency of the reflected wave on the molten metal surface and the reflected wave on the molten metal surface received by the antenna are received, From the difference with the frequency of the microwave transmitted from the microwave rangefinder, the first time from when the microwave is transmitted until the reflected wave at the molten metal surface is received And the difference between the frequency of the reflected wave on the surface of the slag received by the antenna and the frequency of the microwave transmitted from the microwave rangefinder when the reflected wave on the surface of the slag is received.
- the calculated value ⁇ L is calculated in advance by measuring the thickness of the slag whose thickness is known by the microwave distance meter, and calculating the calculated value.
- a correction formula for correcting to a known slag thickness is obtained, and a value obtained by correcting the calculated value continuously measured by the microwave distance meter during operation with the correction formula is defined as the slag thickness.
- molten steel accommodated in a tundish for continuous casting can be applied as the molten metal.
- a value obtained by multiplying the calculated value by a constant is applied as the correction formula, and a numerical value obtained by multiplying the relative dielectric constant of the slag by the power of ⁇ 0.5 is applied as the constant. be able to.
- flux refers to the powder charged on the molten metal surface
- slag refers to the melted flux
- the thickness of the slag floating on the molten metal surface of the present invention even if the slag is as thin as 150 mm or less, the thickness is measured with high accuracy without depending on the operator. be able to. Since the slag in the tundish can be measured without opening the tundish lid, the occurrence of inclusions in the molten steel due to secondary oxidation due to the intrusion of the atmosphere is suppressed, and a slab with high internal quality is obtained. Obtainable. In addition, by controlling the continuous casting operation using the measured value of the slag thickness, it is possible to suppress the slag entrainment that occurs when the ladle is replaced during continuous casting. Can be obtained by distillation.
- the thickness X of the flux in the container, the distance La from the antenna to the bottom surface of the container, and the distance Lb from the antenna to the surface of the flux measured using a microwave with a center frequency of 32 GHz and a modulation amplitude of 8 GHz. It is a figure which shows a relationship.
- the first preliminary experiment is an experiment in which the flux is assumed to be slag and the bottom of the container accommodating the flux is assumed to be the molten steel surface.
- FIG. 1 is a diagram showing the configuration of an experimental apparatus used for measuring the thickness of the flux.
- the experimental apparatus is composed of a microwave rangefinder 1 and a container 10 that contains a flux 13.
- the microwave rangefinder 1 is an FMCW-type microwave rangefinder that emits microwaves to irradiate microwaves to an object for measuring distance (hereinafter also referred to as “measurement object”).
- the antenna 2 that receives the reflected wave reflected by the measurement object, the amplifier 3 that amplifies the signal intensity of the received reflected wave, the transmission of the microwave, and the received reflected wave And a personal computer 4 for collecting and analyzing data.
- the microwave rangefinder 1 is of the FMCW system that continuously modulates the microwave frequency with a predetermined amplitude and a predetermined period with respect to a predetermined center frequency.
- the microwave distance meter 1 uses the difference between the frequency of the reflected wave received from the measurement target unit and the frequency of the microwave transmitted from the microwave distance meter 1 at the time of reception, to The time from when the wave is transmitted to when the reflected wave at the measurement object is received is calculated. Then, a value obtained by substituting the calculated time into the above equation (1) is set as a distance from the antenna to the measurement object.
- Table 1 below shows the characteristics of the flux used in the first preliminary experiment.
- the table shows the composition, basicity and viscosity of the main components, and the balance other than the main components of the flux shown in the table is impurities.
- a so-called general-purpose microwave having a center frequency of 20 GHz and a modulation amplitude of 4 GHz was used.
- the microwave is irradiated into the container 10
- a part is reflected on the surface of the flux 13, and the rest is transmitted through the flux 13 and reflected on the bottom surface 10 a of the container 10.
- it is possible to measure the distance from the antenna 2 to the surface of the flux 13 by changing the amount of the flux 13 in the container 10 while keeping the distance from the antenna 2 to the bottom surface 10a of the container 10 constant.
- the amount of the flux 13 (the thickness X of the flux 13 in the container 10) was investigated.
- the relationship between the distance La from the antenna 2 measured by the microwave rangefinder 1 to the bottom surface 10a of the container 10 and the thickness X of the flux 13 was investigated.
- FIG. 2 is a diagram showing the relationship between the thickness X of the flux in the container, the distance La from the antenna to the bottom surface of the container, and the distance Lb from the antenna to the surface of the flux measured using general-purpose microwaves.
- the distance shown in the figure is a value obtained by substituting the calculated value of the time from when the microwave is transmitted to when the reflected wave at the measurement object is received into the above equation (1).
- the dotted line shown in the figure is a line simply connecting the point that can be measured by the microwave and the point where the thickness of the flux is zero.
- the thickness X of the flux 13 in the container 10 is less than 150 mm, the reflected wave from the bottom surface 10a of the container 10 and the reflected wave from the surface of the flux 13 are not separated. The wave could not be clearly confirmed, and as a result, the distance from the antenna 2 to the surface of the flux 13 could not be measured.
- the thickness X of the flux 13 in the container 10 is 150 mm or more, both the reflected wave from the bottom surface 10a of the container 10 and the reflected wave from the surface of the flux 13 can be clearly confirmed. Therefore, the distance from the antenna 2 to the surface of the flux 13 could be measured.
- the distance La from the antenna 2 measured by the microwave rangefinder 1 to the bottom surface 10a of the container 10 increased in proportion to the increase in the thickness X of the flux 13. This is because the dielectric constant of the flux is different from the dielectric constant of air, and the speed of the microwave that passes through the flux is affected by the flux. From this result, a value obtained by subtracting the distance Lb from the antenna 2 measured by the microwave distance meter 1 to the surface of the flux 13 from the distance La from the antenna 2 measured by the microwave distance meter 1 to the bottom surface 10a of the container 10 ( La ⁇ Lb (hereinafter also referred to as “difference value”) was found to be a value larger than the actual thickness 13 of the flux 13.
- a microwave is transmitted from the difference between the frequency of the reflected wave at the bottom surface 10a of the container 10 received by the antenna 2 and the frequency of the microwave transmitted from the microwave rangefinder 1 when the reflected wave is received.
- the time until the reflected wave at the bottom surface 10a of the container 10 is received is calculated, and this is set as the first time.
- the microwave is transmitted from the difference between the frequency of the reflected wave on the surface of the flux 13 received by the antenna 2 and the frequency of the microwave transmitted from the microwave rangefinder 1 when the reflected wave is received. Then, the time until receiving the reflected wave on the surface of the flux 13 is calculated, and this is set as the second time.
- the above equation (2) is an equation for the difference (L0 ⁇ L1) between the distance L0 from the antenna to the molten steel surface and the distance L1 from the antenna to the slag surface measured with a microwave rangefinder for the slag on the molten steel surface.
- the difference value (La ⁇ Lb) can be expressed by the following (3).
- La ⁇ Lb c ⁇ (t1 ⁇ t2) / 2 (3)
- c speed of microwave in the atmosphere (mm / s)
- t1 first time (s)
- t2 second time (s).
- the present inventors considered that this problem was caused by low measurement accuracy because the wavelength of the general-purpose microwave was as long as several tens of millimeters. And, by using a microwave having a shorter wavelength than the general-purpose microwave and increasing the modulation amplitude, not only the reflected wave on the bottom surface of the container but also the reflected wave on the surface of the flux can be detected stably, We thought that the accuracy of the thickness of the flux measured with the microwave rangefinder could be improved. In the FMCW method, the amplitude and center frequency of frequency modulation are important for improving measurement accuracy.
- the present inventors conducted a second preliminary experiment using a microwave having a center frequency of 32 GHz and a modulation amplitude of 8 GHz using the experimental apparatus shown in FIG.
- FIG. 3 shows the thickness La of the flux in the container, the distance La from the antenna to the bottom of the container, and the flux from the antenna, measured using a microwave with a center frequency of 32 GHz and a modulation amplitude of 8 GHz. It is a figure which shows the relationship with the distance Lb to the surface. As shown in the figure, when this microwave is used, even if the thickness X of the flux in the container is less than 150 mm, if the thickness X is 15 mm or more, the distance from the antenna to the surface of the flux is set. It was measurable. Further, the present inventors have confirmed that the same measurement is possible by using a microwave having a microwave center frequency of 24 to 32 GHz and a modulation amplitude of 8 to 10 GHz.
- FIG. 4 is an example of measurement data when a microwave having a center frequency of 32 GHz and a modulation amplitude of 8 GHz is used.
- the measurement data when the thickness X of the flux 13 in the container 10 is 40 mm are shown. From the figure, it can be seen that the reflected wave on the surface of the flux and the reflected wave on the bottom surface of the container are clearly separated and both can be detected stably.
- the distance La from the antenna to the bottom surface of the container measured with a microwave rangefinder was 545 mm
- Equation (4) is obtained by multiplying the difference value (La ⁇ Lb) calculated from each distance measured by the microwave rangefinder by a constant. According to the study by the present inventors, this constant corresponds to a value obtained by raising the relative dielectric constant ⁇ L of the flux to the power of ⁇ 0.5. In the case of the measurement data shown in FIG. 4, the relative dielectric constant ⁇ L of the flux is 2.33.
- the thickness of the flux can be calculated with high accuracy by correcting the difference value calculated from the distances La and Lb continuously measured by the microwave rangefinder with the equation (4).
- X (La ⁇ Lb) ⁇ ⁇ L ⁇ 0.5 (4)
- X thickness of the flux (mm)
- La distance from the antenna measured with the microwave rangefinder to the bottom of the container (mm)
- Lb distance from the antenna measured with the microwave rangefinder to the surface of the flux Distance (mm)
- ⁇ L relative permittivity of flux.
- FIG. 5 is a schematic diagram showing a state of measuring slag thickness using a microwave rangefinder.
- the flux 13 in the state of floating on the molten steel surface of the molten steel 11 and the slag 12 in which the flux 13 is melted are FMCW type microwave rangefinders, and the center frequency is 24 to 32 GHz, and , Using a microwave having a modulation amplitude of 8 to 10 GHz, a distance L0 from the antenna 2 of the microwave rangefinder to the molten metal surface of the molten steel 11, a distance L1 from the antenna 2 to the interface between the slag 12 and the flux 13, and A test for measuring the distance L2 from the antenna 2 to the surface of the flux 13 was performed.
- FIG. 6 is an example of measurement data for a state in which flux and slag are floating on the molten steel surface.
- the reflected waves on the molten steel surface, the interface between the slag and the flux, and the surface of the flux are clearly separated, and it can be seen that all can be detected stably. .
- the thickness of the slag and the thickness of the flux in a state where the flux and the slag are floating on the molten steel surface are measured with a microwave rangefinder.
- the relative permittivity ⁇ S of the slag is the difference between the actual thickness of the slag and the difference value corresponding to the slag thickness calculated from each distance measured by the microwave rangefinder. Calculate in advance from the correlation.
- T1 (L0 ⁇ L1) ⁇ ⁇ S ⁇ 0.5 (5)
- T2 (L1-L2) ⁇ ⁇ L ⁇ 0.5 (6)
- T1 Thickness of slag (mm)
- T2 Thickness of flux (mm)
- L0 Distance from antenna to molten steel surface measured with microwave rangefinder (mm)
- L1 Microwave rangefinder Distance from the antenna to the interface between the slag and the flux measured in (mm)
- L2 Distance from the antenna to the surface of the flux measured with a microwave rangefinder (mm)
- ⁇ S Dielectric constant of slag
- ⁇ L It is the relative dielectric constant of the flux.
- L1 is “from the antenna measured by the microwave rangefinder to the slag. It was confirmed that the thickness of the slag can be calculated by setting the “distance to the surface”.
- the slag thickness measuring method of the present invention the slag thickness can be measured easily and with high accuracy without depending on the operator. Since the thickness of the slag can be measured as long as it is 2 mm or more, the slag in the tundish, which is relatively thin, should be thick enough to reduce the quality of the slab due to slag entrainment. Thickness can be measured. Further, by disposing the antenna in the tundish, the thickness of the slag can be continuously measured without contact without opening the lid of the tundish.
- FIG. 7 is a diagram showing a configuration of a test apparatus used for measuring the slag thickness.
- the test apparatus includes a microwave distance meter 1 and a high-frequency melting furnace (atmospheric furnace) 15.
- the molten steel 11 is accommodated in a heated state.
- the flux is introduced into the high-frequency furnace 15, the flux is melted by the heat of the molten steel 11, and is separated into a slag 12 layer (molten layer) and a flux 13 layer (powder layer) on the molten steel 11.
- the microwave rangefinder 1 includes an antenna 2, a waveguide pipe 5, a reflection plate 6, and an amplifier 3. Microwaves transmitted from the antenna 2 are reflected by the reflector 6 and irradiated into the high-frequency furnace 15, and reflected by the molten steel 11, the interface between the slag 12 and the flux 13, and the surface of the flux 13. . Thereafter, the light is reflected again by the reflecting plate 6, guided by the waveguide pipe 5, and received by the antenna 2. In this test, the distance from the microwave receiving / transmitting part of the antenna 2 to the microwave reflecting part of the reflector 6 was set to 1000 mm.
- ⁇ Test conditions> In the high frequency furnace 15, 200 kg of steel material was melted to obtain molten steel 11. The flux was charged into the high-frequency furnace 15 in six steps. The amount of flux input per time was 1.3 kg. This is an amount such that the thickness in the high-frequency furnace 15 (the value obtained by dividing the volume of the flux by the cross-sectional area in the cylindrical furnace) is 20 mm. The flux used was of the characteristics shown in Table 1.
- the thickness of the flux and slag is measured with the microwave distance meter 1, and the flux and slag are manually operated by an operator (hereinafter referred to as "hand measurement") using a metal measuring rod.
- the thickness of was measured.
- a microwave having a center frequency of 32 GHz and a modulation amplitude of 8 GHz was used.
- the relative dielectric constant ⁇ S of the slag was 35. This is because the distance from the antenna to the molten steel surface measured with a microwave rangefinder and the microwave distance meter for a slag of a predetermined thickness (6.5 mm by hand measurement) that floated on the molten steel surface in advance. This is a value calculated from the above equation (5) using the distance (difference value 38.5 mm) from the antenna to the interface between the slag and the flux measured in step (1).
- FIG. 8 is a diagram showing the relationship between the number of fluxes fed and the slag and flux thicknesses measured by hand measurement. From the figure, it can be seen that the thickness of the slag and flux in the high-frequency furnace both increase with an increase in the number of times of flux injection.
- FIG. 9 is a diagram showing the relationship between the number of fluxes, the slag thickness measured by hand measurement, and the slag thickness measured by the slag thickness measurement method of the present invention.
- FIG. 9 shows that the slag thickness by the hand measurement is equivalent to the slag thickness by the slag thickness measurement method of the present invention. This shows that according to the slag thickness measuring method of the present invention, the thickness of the slag can be continuously measured with high accuracy.
- the slag thickness measurement method of the present invention even when the slag is as thin as 150 mm or less, the thickness can be measured easily and with high accuracy without depending on the operator. Since the slag in the tundish can be measured without opening the tundish lid, the occurrence of inclusions in the molten steel due to secondary oxidation due to the intrusion of the atmosphere is suppressed, and a slab with high internal quality is obtained. Obtainable. Further, by controlling the continuous casting operation using the measured value of the slag thickness, it is possible to suppress slag entrainment or the like generated at the time of replacing the ladle at the time of continuous casting and obtain a high quality slab.
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Abstract
Description
L=c・t/2 …(1)
ここで、c:大気中におけるマイクロ波の速度(mm/s)、t:受信した反射波の周波数と受信した時点でマイクロ波距離計から発信されているマイクロ波の周波数との差から算出した時間(s)である。
ΔL=L0-L1=(c・t1-c・t2)/2
=c・(t1-t2)/2 …(2)
ここで、c:大気中におけるマイクロ波の速度(mm/s)、t1:第1の時間(s)、t2:第2の時間(s)である。
1-1.測定可能なフラックス厚さの確認(第1予備実験)
タンディッシュ内の溶鋼湯面上に浮遊するスラグの厚さは、通常は10~20mmの範囲内にある。そこで、いわゆる汎用マイクロ波を用いた場合に、マイクロ波距離計のアンテナからスラグ表面までの距離、および同アンテナから溶鋼湯面までの距離を、スラグの厚さを算出できる程度に測定することが可能かどうかを実験室での実験(第1予備実験)で確認した。
La-Lb=c・(t1-t2)/2 …(3)
ここで、c:大気中におけるマイクロ波の速度(mm/s)、t1:第1の時間(s)、t2:第2の時間(s)である。
本発明者らは、第1予備実験の結果について検討し、実際のフラックスの厚さXと、マイクロ波距離計で測定した距離LaおよびLbから算出した差分値(La-Lb)との相関から、この差分値を実際のフラックスの厚さXに補正する補正式をあらかじめ求めておき、この補正式によって、マイクロ波距離計で連続的に測定した値に基づく差分値を補正することにより、マイクロ波距離計を用いてフラックスの厚さを連続的に高い精度で測定できると考えた。この補正式は、後述する通り、差分値に定数を乗ずるものであり、定数はフラックスの比誘電率を-0.5乗した値である。
X=(La-Lb)・εL -0.5 …(4)
ここで、X:フラックスの厚さ(mm)、La:マイクロ波距離計で測定したアンテナから容器の底面までの距離(mm)、Lb:マイクロ波距離計で測定したアンテナからフラックスの表面までの距離(mm)、εL:フラックスの比誘電率である。
図5は、マイクロ波距離計によるスラグの厚さの測定状態を示す模式図である。同図に示すように溶鋼11の湯面上に浮遊している状態のフラックス13とフラックス13が溶融したスラグ12について、FMCW方式のマイクロ波距離計で、中心周波数が24~32GHzであり、且つ、変調振幅が8~10GHzであるマイクロ波を用いて、マイクロ波距離計のアンテナ2から溶鋼11の湯面までの距離L0、アンテナ2からスラグ12とフラックス13の界面までの距離L1、および、アンテナ2からフラックス13の表面までの距離L2を測定する試験を行った。
T1=(L0-L1)・εS -0.5 …(5)
T2=(L1-L2)・εL -0.5 …(6)
ここで、T1:スラグの厚さ(mm)、T2:フラックスの厚さ(mm)、L0:マイクロ波距離計で測定したアンテナから溶鋼湯面までの距離(mm)、L1:マイクロ波距離計で測定したアンテナからスラグとフラックスの界面までの距離(mm)、L2:マイクロ波距離計で測定したアンテナからフラックスの表面までの距離(mm)、εS:スラグの比誘電率、εL:フラックスの比誘電率である。
図7は、スラグの厚さの測定に用いた試験装置の構成を示す図である。試験装置は、マイクロ波距離計1と高周波溶解炉(大気炉)15からなる。
高周波炉15では、200kgの鋼材を溶解し溶鋼11とした。フラックスは、6回に分けて高周波炉15内に投入した。1回あたりのフラックスの投入量は1.3kgとした。これは、高周波炉15内での厚さ(フラックスの体積を円筒形の炉内の横断面積で割った値)が20mmとなる量である。使用したフラックスは、表1に示した特性のものとした。
図8は、フラックスの投入回数と、ハンド測定で測定したスラグおよびフラックスの厚さとの関係を示す図である。同図から、フラックスの投入回数の増加に伴って、高周波炉内のスラグおよびフラックスの厚さが、いずれも増加していることがわかる。
Claims (3)
- 中心周波数が24~32GHzであり、且つ、周波数変調の振幅が8~10GHzである周波数変調マイクロ波を、アンテナから発信して受信するマイクロ波距離計を使用し、溶融金属の湯面上に浮遊するスラグの厚さを測定する方法であって、
前記マイクロ波距離計が、
前記アンテナから前記溶融金属および前記スラグに向けて前記マイクロ波を発信し、前記発信したマイクロ波の前記溶融金属湯面での反射波および前記スラグ表面での反射波を前記アンテナで受信し、
前記アンテナで受信された前記溶融金属湯面での反射波の周波数と、該反射波を受信した時点で発信されているマイクロ波の周波数との差を用いて、前記マイクロ波を発信してから前記溶融金属湯面での反射波を受信するまでの第1の時間を算出するとともに、
前記アンテナで受信された前記スラグ表面での反射波の周波数と、該反射波を受信した時点で発信されているマイクロ波の周波数との差を用いて、前記マイクロ波を発信してから前記スラグ表面での反射波を受信するまでの第2の時間を算出し、
前記第1の時間および前記第2の時間を用いて、下記(1)式で表される計算値を算出するものであり、
あらかじめ、前記マイクロ波距離計によって厚さが既知のスラグの厚さを測定して前記計算値を算出し、該計算値を前記厚さが既知のスラグの厚さに補正する補正式を求めておき、
操業時に前記マイクロ波距離計で連続的に測定した前記計算値を前記補正式で補正した値を、スラグの厚さとすることを特徴とする、溶融金属湯面上に浮遊するスラグ厚さ測定方法。
ΔL=c・(t1-t2)/2 …(1)
ここで、ΔL:計算値(mm)、c:大気中におけるマイクロ波の速度(mm/s)、t1:前記第1の時間(s)、t2:前記第2の時間(s)である。 - 前記溶融金属が、連続鋳造用タンディッシュ内に収容された溶鋼であることを特徴とする、請求項1に記載の溶融金属湯面上に浮遊するスラグの厚さ測定方法。
- 前記補正式が前記計算値に定数を乗ずるものであり、前記定数が前記スラグの比誘電率を-0.5乗した数値であることを特徴とする、請求項1または2に記載の溶融金属湯面上に浮遊するスラグの厚さ測定方法。
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CN106643588A (zh) * | 2016-10-31 | 2017-05-10 | 攀钢集团攀枝花钢铁研究院有限公司 | 一种用微波测量铁水罐铁水带渣厚度的方法 |
WO2020104217A1 (de) * | 2018-11-21 | 2020-05-28 | Primetals Technologies Austria GmbH | Dickenmessung einer schicht eines giesspulvers in einer kokille |
CN114449723A (zh) * | 2022-04-08 | 2022-05-06 | 北京奥邦新材料有限公司 | 一种提升中间包等离子加热系统功率因数的装置和方法 |
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CN107063142B (zh) * | 2017-05-04 | 2019-09-10 | 盐城工学院 | 一种板坯连铸凝固坯壳厚度检测系统 |
JP6822388B2 (ja) * | 2017-12-12 | 2021-01-27 | 日本製鉄株式会社 | レベル計測装置 |
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0172394A1 (de) * | 1984-08-20 | 1986-02-26 | MANNESMANN Aktiengesellschaft | Verfahren und Einrichtung zum Kontrollieren von Schlacke in einem Vorratsbehälter beim Stranggiessen von Metall, insbes. von Stahl |
JPH1080762A (ja) * | 1996-09-06 | 1998-03-31 | Nkk Corp | 溶鋼鍋のスラグ流出予測方法及び装置 |
JP2003344142A (ja) * | 2002-05-24 | 2003-12-03 | Jfe Steel Kk | マイクロ波レベル計による溶融金属レベル及びスラグ層厚の測定方法及び装置 |
WO2005062846A2 (en) * | 2003-12-23 | 2005-07-14 | Uec Technologies Llc | Tundish control |
JP2011043343A (ja) * | 2009-08-19 | 2011-03-03 | Wire Device:Kk | マイクロ波によるスラグ厚の測定方法及び測定装置 |
JP2011510279A (ja) * | 2008-01-18 | 2011-03-31 | タタ、スティール、アイモイデン、ベスローテン、フェンノートシャップ | 鋳型中のスラグ及び溶融金属の表面をモニタリングする方法及び装置 |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1137371C (zh) * | 2002-02-05 | 2004-02-04 | 北京大学 | 短脉冲激光超声精确测厚方法及装置 |
CN100416222C (zh) * | 2003-06-23 | 2008-09-03 | 仁宝电脑工业股份有限公司 | 膜厚量测方法及微波量测设备 |
AR086927A1 (es) * | 2011-06-16 | 2014-01-29 | Avemis S A S | Dispositivo para medir el espesor de la escoria |
JP5800241B2 (ja) * | 2012-08-08 | 2015-10-28 | 新日鐵住金株式会社 | 連続鋳造用鋳型内の溶融金属の湯面レベル及びモールドパウダー厚の測定方法 |
CN203286997U (zh) * | 2013-05-07 | 2013-11-13 | 莱芜钢铁集团有限公司 | 一种铁水渣厚测量装置 |
-
2014
- 2014-07-30 CN CN201480080886.3A patent/CN106537088A/zh active Pending
- 2014-07-30 KR KR1020177000579A patent/KR20170014002A/ko active Search and Examination
- 2014-07-30 WO PCT/JP2014/070079 patent/WO2016016967A1/ja active Application Filing
- 2014-07-30 BR BR112017001205A patent/BR112017001205A2/pt not_active Application Discontinuation
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0172394A1 (de) * | 1984-08-20 | 1986-02-26 | MANNESMANN Aktiengesellschaft | Verfahren und Einrichtung zum Kontrollieren von Schlacke in einem Vorratsbehälter beim Stranggiessen von Metall, insbes. von Stahl |
JPH1080762A (ja) * | 1996-09-06 | 1998-03-31 | Nkk Corp | 溶鋼鍋のスラグ流出予測方法及び装置 |
JP2003344142A (ja) * | 2002-05-24 | 2003-12-03 | Jfe Steel Kk | マイクロ波レベル計による溶融金属レベル及びスラグ層厚の測定方法及び装置 |
WO2005062846A2 (en) * | 2003-12-23 | 2005-07-14 | Uec Technologies Llc | Tundish control |
JP2011510279A (ja) * | 2008-01-18 | 2011-03-31 | タタ、スティール、アイモイデン、ベスローテン、フェンノートシャップ | 鋳型中のスラグ及び溶融金属の表面をモニタリングする方法及び装置 |
JP2011043343A (ja) * | 2009-08-19 | 2011-03-03 | Wire Device:Kk | マイクロ波によるスラグ厚の測定方法及び測定装置 |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106643588A (zh) * | 2016-10-31 | 2017-05-10 | 攀钢集团攀枝花钢铁研究院有限公司 | 一种用微波测量铁水罐铁水带渣厚度的方法 |
WO2020104217A1 (de) * | 2018-11-21 | 2020-05-28 | Primetals Technologies Austria GmbH | Dickenmessung einer schicht eines giesspulvers in einer kokille |
AT521924A1 (de) * | 2018-11-21 | 2020-06-15 | Primetals Technologies Austria GmbH | Dickenmessung einer Schicht eines Gieß- oder Abdeckpulvers in einem metallurgischen Gefäß |
AT521924B1 (de) * | 2018-11-21 | 2021-03-15 | Primetals Technologies Austria GmbH | Dickenmessung einer Schicht eines Gieß- oder Abdeckpulvers in einer Kokille |
CN114449723A (zh) * | 2022-04-08 | 2022-05-06 | 北京奥邦新材料有限公司 | 一种提升中间包等离子加热系统功率因数的装置和方法 |
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