JPS6254116A - Shape measuring method for hot plate material - Google Patents

Abstract

PURPOSE:To presume wave distortion of plate material after cooling during heating with good accuracy by correcting the thermal expansion on a measured result of a hot wave-distortional shape based on the measured result of a temperature distribution of the hot plate material. CONSTITUTION:When a hot-rolled steel plate 10 is being rolled or after the steel plate is rolled, the width and the edge position are measured by a width edge meter 16 and edge position meters 18 and 20 while the steel plate is conveyed by a table roller 12. Further, at the same time, the temperature distribution of the steel plate 10 in the width direction is measured by a radiation thermometer 22 and the wave- distortional shape of the steel plate 10 is measured by a range finder 24. In this way, the width and the position of the edge at a certain position in the (y) direction and the temperature and height of each position in the (x) direction of the position in the (y) direction are measured and inputted to an arithmetic indicator 26 by a pulse from a pulse transmitter 14 for every prescribed conveyance distance and a map of the width, the edge position, the temperature and the height is prepared. Then, the indicator 26 calculates the flat shape of the plate after the plate is cooled and corrected to the flatness using the distribution of the temperature and height and adding the thermal dimensional correction and the wave-distortional correction.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for measuring the shape of hot-worked sheet materials, and is particularly suitable for measuring the planar shape and wave distortion of thick steel plates, hot-rolled steel strips, etc. It concerns an improvement in the method.

[Conventional technology]

When rolling hot plate materials, especially thick steel plates and hot-rolled steel strips, flat shape defects, especially bends, and wave distortions such as ear waves and mid-elongation (
(Poor flatness) may occur. If bending occurs, there are problems such as not being able to collect the desired product or damaging the equipment during rolling. Moreover, wave distortion significantly reduces product value. Therefore, knowing the planar shape and wave distortion is very important in determining the rolling method in the next rolling pass and in determining the disposal method of the plate. Therefore, wave distortion measurement techniques such as those proposed in Japanese Patent Application Laid-Open No. 53-31159, Japanese Patent Publication No. 48-3
Planar shape measurement techniques such as those proposed in No. 2744 have been developed and are used in both cold and hot applications.

[Problems to be solved by the invention]

However, the temperature distribution of the plank is not necessarily uniform;
The amount of thermal expansion r& due to temperature distribution is also often non-uniform. Therefore, in such a case, if the above-mentioned technique is used as it is to measure the hot material, even if the hot measurement can be made accurately, after the hot material has cooled, the measurement result may be different from the above measurement result. It does not take into account the actual value, and errors occur in wave distortion and planar shape measurement due to the plate wall temperature distribution. For example, uneven heating (unilateral burning) that occurs when a slab is heated in a heating furnace causes a temperature distribution with a substantially uniform gradient in the width direction of the slab. At this time, since the deformation resistance is low on the high temperature side, the thickness of the plate after rolling becomes thinner, and as a result, the plate stretches better than the opposite side, causing bending (camber) in the plate. On the other hand, there is a technique, as proposed in Japanese Patent Laid-Open No. 49-96955, in which the bending of the plate is eliminated by changing the difference in opening between the left and right O-ru. Furthermore, there is a technique for correcting wave distortion using a straightening machine. However, if the hot measurement values are used as they are, the reduction setting of the straightening machine cannot be set sufficiently accurately for wave distortion, and the flat shape cannot be adjusted properly during rolling after the rolled material is cooled. The planar shape could not be corrected in consideration of the planar shape, and it could not be said that the hot measurement results were sufficiently reflected in terms of yield, etc. That is, the heat shrinkage of the steel cap after rolling is relatively 10-1.
It can be on the order of ~10-2. On the other hand, distortion of the order of 10-3 is a problem with bending wave distortion of the plate material, and it is necessary to actually measure such wave distortion and mU distribution and correct the bending wave distortion of the plate material. However, in the conventional measuring method of tortuosity wave distortion, there is no measuring method that involves such correction. Object of the Invention The present invention has been made to solve the above-mentioned conventional problems, and provides a method for measuring the shape of a hot plate material that can accurately estimate the wave distortion of the plate material after cooling. The primary purpose is to provide. A second object of the present invention is to provide a method for measuring the shape of a hot plate I, which can accurately estimate the planar shape of the plate material after it has been cooled and straightened.

[Means to solve the problem]

As shown in FIG. 1, when measuring the wave distortion shape of a hot plate material, the present invention simultaneously measures the temperature distribution of the hot plate material, and based on the measurement results of the temperature distribution, The first objective is achieved by correcting the wave distortion shape measured by heat V and swelling in order to estimate the wave distortion shape after cooling of the plate material. Furthermore, when measuring the planar shape of a hot work plate, the present invention also measures the temperature distribution and wave distortion shape of the hot work board at the same time, as shown in FIG. The second objective is achieved by correcting the hot planar shape measurement results based on the measurement results and estimating the planar shape of the plate after cooling and straightening. (Function) A plate material during hot rolling or immediately after rolling generally has a planar temperature distribution and wave distortion of the plate thickness.As shown in FIG. The X-axis is set at , and the tip is x = Q.The y-axis is set in the width direction of the board, that is, the direction perpendicular to the conveyance direction, and the width center is set at y-0.Also, the point A on the board The temperature difference between (x, v) and the air temperature is θ<x
, y > binding, and the inclination angle of the plate wave in the longitudinal direction is β(x,
y), and the height of the wave distortion amplitude from the normal position to h(y
), and the wavelength is 1(y). Then, after cooling the plate material around point A to air temperature and straightening it flat, point B (x 0 dx, y
+dy) is considered as point B' (x
+dx'', y +dy'), and the following relationship holds true: dX=(1-+4-θ(x', y'))dx'
(1) dV=(1+α・θ(x', y'))
dy'...(2)dx'-dX"-CQS
β ・(3)β=(X/J2)
・2π+β0...(4)dh(X
, V ) = dX' - tan β ・
(5) Here, α is the linear expansion coefficient. Mende equations (1) and (2) can be approximated as follows. dx'=(1-(X・θ(x, V))dx
-(1')dy' = (1-α・θ(X, V)
)dV...(2') Therefore, the following relationship holds true. dx" = (1-α・θ(X, V))xSe
C((x/i)・2π+βG)−dx...(6) dl+(x Sy) −(1−α・θ(x, y
))xtan((x/12)・2π×β0)・d
x ... (7) From equations (2), (6), and (7), the planar shape (Xe'', we') and wave distortion height h' (x, y) after cooling are as follows. It is expressed as: xe″=, r”(1-(X ・θ(X, l/))-se
c((X/fl)・2π+β0)・dx...
(8) Ve'=J"(1-α・θ(x,y))dy...(9
) h' (x, V)=/''(1-a-θ(X, l/
)'jxtan((x/i)・2π+β0)・dx (10) Here, (Xe, Me) are the coordinates of an arbitrary point at the end position representing the planar shape of the high-temperature plate material. Therefore, this (X
The difference between e, Ve) and (Xe', Ve') and l
The difference between +(x, y) and il'(X, y) becomes the measurement error of the planar shape and wave distortion shape due to cooling. Therefore, in the present invention, when measuring the wave distortion shape of the hot plate material, the temperature distribution of the hot plate material is also measured at the same time, and based on the measurement result of the temperature distribution, the measurement result of the wave distortion shape in the hot process is determined. Linear expansion correction 7 is applied. Therefore,
The shape of wave distortion after cooling the plate material can be accurately estimated in the hot state. In addition, when measuring the planar shape of the hot work plate H, the temperature distribution and wave distortion shape of the hot work board material are also measured at the same time, and based on the measurement results of the temperature distribution and wave distortion shape, the planar shape during hot work is measured. I am trying to correct the results. Therefore, the planar shape of the plate material after cooling and straightening can be accurately estimated in the hot state. Note that cooling is based on natural cooling or slow cooling using a small amount of cooling water, but for strong cooling using human cooling water, it is possible to achieve high accuracy by taking into account the cooling conditions and making further corrections. Measurement results can be obtained.

【Example】

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of a method for measuring the shape of a hot-rolled steel sheet, in which the method for measuring the shape of a hot-rolled steel sheet according to the present invention is adopted, will be described in detail below with reference to the drawings. The present embodiment is constructed as shown in FIG.
16 is a width edge meter that measures the width and edge position of the hot rolled steel plate 10 at the same time; 18 and 20 are edge meters that measure the edge position of the hot rolled steel plate 10; Position S1.22 is hot rolled steel plate 1
Hot rolled steel plate 1 for measuring the surface temperature θ of 0 in the width direction
Numerous radiation thermometers 24 are arranged in parallel in the width direction of the hot rolled steel sheet 10, and 24 are distance meters arranged in large number in the width direction of the hot rolled steel sheet 10 for measuring the wave distortion shape of the hot rolled steel sheet 10 in the width direction. , 26 is a PAn display that calculates and displays the shape of the hot rolled steel sheet 10. The width edge meter 16 and edge position meter 18.20 may be of a type that receives infrared light generated by the hot rolled steel sheet 10 itself, or may be of a type that receives infrared light generated by the hot rolled steel sheet 10, or a light source placed on the opposite side to the hot rolled steel sheet 10. A type that utilizes the shielding effect of the hot rolled steel plate 10 may also be used. Further, these detectors may be a COD camera or the like, or a combination of a rotating slit drum and a photomultiplier. As shown in FIG. 4, the radiation thermometer 22 is constructed by arranging a large number of radiation thermometers 22 in the width direction of the hot rolled steel sheet 1o, that is, in the y direction, and measuring the radiation of the radiation thermometers 22. )j The method may be one in which the signals of the thermometer are scanned and collected, or the method may be one in which one radiation thermometer is scanned in the board width direction. Further, the distance meter 24 may be a method in which a number of distance meters such as an optical micrometer method using a laser beam, an underwater ultrasonic method, or a water column electrical resistance method are installed in the y direction, and their outputs are scanned and collected. can do. The operation of the embodiment will be explained below. While the hot-rolled steel sheet 10 is being rolled, or while being conveyed by the table rollers 12 after being rolled, the width and edge position are measured by the width edge meter 16 and edge position meter 18, 20. At the same time, the radiation thermometer 22 measures the temperature distribution in the width direction of the hot-rolled steel sheet 10, and the distance meter 24 measures the wave distortion shape, that is, the distribution of height h, of the hot-rolled steel sheet 10. Then, the width and edge position at a certain position in the ■ direction, and the temperature and height at each X direction position of that position in the The information is input to the display 26, and a map of width, edge position, temperature, and height is created.The calculation display 26 uses the temperature and height distribution to
Based on equations (7) and (8), thermal dimension correction and wave distortion correction are added, and cold! J] Find the planar shape of the plate after it has been straightened to be flat. Assuming that the shape before correction is expressed by (xe, we) and the wave distortion is expressed by h<x, y), the shape after correction is expressed by equations (8), (9), and wave distortion. The distortion is (10)
It is expressed by the formula. Finished dimensions are thickness 12mm, width 50001111, length 4
When we measured the temperature, strain, and planar shape of a 0,000 mm thick plate after rolling, we found that the temperature was on the working side (WS) as shown in Figure 5.
) is 700″C1 center part is 900′C1 drive flll(
DS> is 800″C, and the distortion is symmetrical TeΔ for both WS and DS.
H(V) 712-441 degrees λ=o. The ear wave was 5%, and the planar shape had a uniform curvature, with the DS convexly curved by 150 mm. Here, ΔH
(y) is 1/2 of the wave distortion height, as shown in FIG. After slowly cooling this thick plate to air temperature by spraying mist with a uniform quantity distribution, the strain was measured, and it was found that λ = 0.67.
% ear waves. Furthermore, after straightening the cooled thick plate using a roller straightener to make it flat, the planar shape was measured.
The amount of bend was 185 mm. In such an example, when the hot measurement value is corrected according to the present invention, the estimated value based on the hot measurement value becomes λ=
0.61%, curve interval = 200 dragons. This means that the error for the value after cooling or after correction is 65, respectively.
%, corresponding to a decrease of 57%. In the above embodiments, the measurement results of the hot planar shape are corrected based on the measurement results of the temperature distribution and wave distortion shape of the hot rolled steel sheet 10, and the planar shape of the hot rolled steel sheet 10 after cooling and straightening is corrected. Although the shape was estimated, the scope of application of the present invention is not limited to this, and when measuring the wave distortion shape of the hot rolled steel sheet 10, based on the measurement results of the temperature distribution,
It is clear that the present invention can be similarly applied to the case where the wave distortion shape of a plate material is estimated after cooling by thermal expansion correction of the measurement results of the wave distortion shape in hot conditions.

【Effect of the invention】

As explained above, according to the present invention, the wave distortion shape and the cooling f! It becomes possible to hotly and accurately estimate the planar shape after I and after correction. Therefore, regarding the wave distortion shape, it is possible to accurately set the rolling opening of the straightening roll in the hot straightening machine. In addition, regarding the planar shape, it is possible to accurately correct the shape based on the predicted shape after cooling and straightening during rolling, which has an excellent effect that greatly contributes to improving yield.

[Brief explanation of the drawing]

1 and 2 are flowcharts without showing the gist of the method for measuring the shape of hot plate materials according to the present invention, and FIG. The perspective view shown in FIG. 4 does not show the configuration of the embodiment of the hot-rolled steel sheet shape measuring device to which the present invention is adopted, but is a perspective view partially including a block diagram.
FIG. 5 is a perspective view showing an example of the temperature distribution of a hot rolled steel sheet measured in the above example, and FIG. 6 is a longitudinal sectional view showing an example of wave distortion. 10...Hot rolled steel plate, 14...Pulse transmitter, 1
6...Width edge meter, 18.20...Edge position meter, 22...Radiation thermometer, 24...Distance meter, 26.
...Calculation display.

Claims (2)

[Claims] (1) When measuring the wave distortion shape of the hot plate material, the temperature distribution of the hot plate material is also measured at the same time, and based on the measurement result of the temperature distribution, the measurement result of the wave distortion shape in the hot process is corrected for thermal expansion. A method for measuring the shape of a hot plate material, characterized by estimating the wave distortion shape of the plate material after cooling. (2) When measuring the planar shape of the hot plate material, the temperature distribution and wave distortion shape of the hot plate material are also measured at the same time, and the planar shape during hot processing is measured based on the measurement results of the temperature distribution and wave distortion shape. A method for measuring the shape of a hot plate material, the method comprising correcting the results to estimate the planar shape of the plate material after cooling and straightening.