JPH04320911A - Measuring method for plate thickness of hot rolled plate material - Google Patents

Abstract

PURPOSE:To eliminate an error on the occasion when the plate thickness of a hot rolled plate material obtained by a radiation thickness gage is corrected to be the plate thickness at a prescribed reference temperature, by determining accurately temperatures at a point of the central part and points of the opposite end parts in the direction of the plate width in which the plate thickness of the material is to be measured. CONSTITUTION:A temperature profile in the direction of the plate width of a hot rolled steel plate S is measured by a scanning-type thermometer 3, while a temperature at a central point B in the plate width of the steel plate S is measured by a radiation thermometer 4. On the basis of the data on the temperature profile, a temperature difference between a point A of the end part in the direction of the plate width and the central point B and a temperature difference between a point C of the end part in the direction of the plate width and the central point B are determined. Based on these temperature differences and a measured value of the temperature at the central point B in the plate width, temperatures at the points A and C of the opposite end parts of the steel plate S are calculated. On the basis of calculated values of these temperatures at the points A and C of the opposite end parts and the measured value of the temperature at the central point B in the plate width, the plate thickness at each of the plate thickness measuring points A, B and C at which measurement is made simultaneously by a three-head type radiation thickness gage 1 is corrected to be a value at a prescribed reference temperature, and the plate thickness is measured therefrom.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention measures the thickness of a hot-rolled plate material such as a hot-rolled steel plate in the width direction using a three-head type radiation thickness gauge disposed at the exit side of a rolling mill. The present invention relates to a method for measuring the thickness of a hot-rolled plate material, which allows the thickness of the hot-rolled plate material to be accurately and precisely measured when simultaneously measuring the thickness of the center point and both end points.

0002

[Prior Art] A three-head radiation thickness gauge is used to simultaneously measure the thickness of a hot-rolled plate such as a steel plate at the center point and both end points in the width direction, and the thickness of the hot-rolled plate is measured using a thermometer. A method in which the plate thickness at the center point and both end points obtained based on the temperature measurement value is corrected to the value at a predetermined reference temperature, and the plate thickness at the above three points of the hot rolled plate material is measured is as follows. Conventionally, the following two methods have been adopted.

[0003] That is, the temperature at both end points in the width direction of the hot rolled plate material is not measured, but only the temperature at the center point of the plate width is measured using a thermometer such as a radiation thermometer, and based on this temperature measurement, The plate thickness at the center point and both end points in the plate width direction obtained by simultaneous measurement using a radiation thickness gauge is corrected to the value at a predetermined reference temperature, and the plate thickness is calculated at the plate width center point and in the plate width direction of the hot rolled plate material. This method measures the plate thickness at both end points.

[0004] Also, the temperature at the center point of the board width and at both end points is measured with thermometers installed individually corresponding to these measurement positions, and the temperature obtained by the radiation thickness meter is calculated based on the temperature measurement value of each thermometer. A method of measuring the thickness of a hot-rolled sheet material at the central point of the sheet width and at both end points in the sheet width direction by correcting the sheet thickness at each point at the center of the sheet width and at both ends of the hot-rolled sheet material to the value at a predetermined reference temperature. is also being carried out.

[0005]

[Problem to be Solved by the Invention] However, in the former conventional method, the thickness of the plate at a predetermined reference temperature is determined by performing correction using only the temperature measurement value at the center point of the plate width. Due to the influence of rolling conditions such as the number of hot rolling passes and the presence or absence of tentering rolling, a temperature difference occurs in the width direction of the hot rolled sheet material, and in particular, the temperature at both end points in the sheet width direction is lower than that in the center. Since the above temperature measurement value used for correction does not match the actual temperature value at both end points in the sheet width direction, the predetermined reference temperature to be determined at both end points of the hot rolled sheet material The disadvantage is that there is an error in the plate thickness.

In addition, in the latter conventional method, each thermometer that measures the temperature at each plate thickness measurement point at the center of the plate width and at both ends in the width direction of the plate is adjusted so that there are no individual differences in sensitivity. Since it is not easy to maintain this method, there is a drawback that, as time passes, errors occur in the thickness of the hot-rolled sheet material obtained by making corrections based on the temperature measurements of these thermometers.

The present invention solves the above-mentioned drawbacks and accurately determines the temperature at the center point and both end points in the width direction of the hot rolled sheet material in which the thickness is to be measured using a radiation thickness meter. By eliminating the error when correcting the plate thickness to the plate thickness at a predetermined reference temperature, it is possible to accurately measure the plate thickness at the center point of the plate width and at both end points in the plate width direction of the hot rolled plate material. The purpose of this invention is to provide a method for measuring the thickness of hot-rolled plate materials.

[0008]

[Means for Solving the Problems] In order to achieve the above object, a method for measuring the thickness of a hot rolled plate material according to the present invention includes the following steps:
Based on the temperature measurement value of the hot-rolled plate material measured using a thermometer, the plate thickness at the center point and both end points in the width direction of the hot-rolled plate material obtained by simultaneous measurement using a radiation thickness meter. In the method of measuring the plate thickness at the three thickness measurement points of the hot-rolled plate material by correcting it to a value at a predetermined reference temperature, the temperature profile in the width direction of the hot-rolled plate material is measured with a scanning thermometer; , one of the plate thickness measurement points is used as a reference measurement point, and its temperature is measured using a reference point temperature measuring thermometer, and from the temperature profile data obtained by the scanning thermometer, one of the plate thickness measurement points is determined. The temperature difference between the thickness measurement point and the reference measurement point, and the temperature difference between the other plate thickness measurement point and the reference measurement point are calculated, and the calculated temperature difference and the reference measurement point using the reference point temperature measuring thermometer are calculated. From the temperature measurement value, calculate the temperature at two thickness measurement points other than the reference measurement point of the hot rolled plate material, and calculate the calculated temperature values at the two thickness measurement points other than the reference measurement point and the reference measurement point. By correcting the plate thickness at each plate thickness measurement point obtained by the radiation thickness meter to the value at a predetermined reference temperature based on the temperature measurement value, the center of the hot rolled plate material in the width direction is This method is characterized by measuring the plate thickness at the end point and both end points.

[0009]

[Operation] In the plate thickness measurement method configured as described above, one of the plate thickness measurement points at the center of the plate width and at both ends in the width direction of the hot rolled plate material is determined as a reference measurement point, The temperature at this reference measurement point is measured by a thermometer for measuring reference point temperature. In this case, if the reference measurement point is, for example, the center point of the sheet width, then from the temperature profile data in the sheet width direction of the hot rolled sheet material obtained by a scanning thermometer, one end point in the sheet width direction and the sheet The temperature difference with the width center point and the temperature difference between the other end point in the board width direction and the board width center point are determined.

Since these temperature differences were measured using one scanning thermometer, they do not include errors due to individual differences in thermometers, and are also accurate between the center point of the sheet width and the end point in the sheet width direction. Since it is a relative temperature difference, even if the sensitivity of the scanning thermometer changes over time, the influence of this is extremely small, and the value indicates an accurate temperature difference. Therefore, the calculated temperature value at both end points in the width direction of the hot rolled sheet material calculated from these temperature differences and the temperature measurement value at the center point of the sheet width measured by the reference point temperature measuring thermometer is It shows the accurate temperature value at a certain point.

[0011] Thereby, based on the calculated temperature values at both end points and the temperature measurement value at the center point of the plate width, the plate thickness at each plate thickness measurement point obtained by the radiation thickness meter is set to a predetermined reference temperature. By correcting to the respective values, correction errors due to inaccurate temperatures are eliminated, and the plate thickness at the center point and both end points in the plate width direction of the hot rolled plate material can be accurately measured. In this case, the reference measurement point to be measured by the thermometer for reference point temperature measurement is one of the three thickness measurement points: the center point of the plate width and the points at both ends in the width direction. Good to have.

0012

EXAMPLES The present invention will be explained below based on examples. FIG. 1 is a diagram showing the configuration of an apparatus for implementing the method according to the present invention, and FIG. 2 is a diagram for explaining the temperature profile of a hot rolled steel plate obtained by a scanning thermometer according to the method according to the present invention. .

In FIG. 1, reference numeral 1 denotes a three-head radiation thickness gauge installed at a predetermined position on the exit side of a hot rolling mill (not shown). As shown in the figure, this three-head type radiation thickness meter 1 measures a hot-rolled hot-rolled steel sheet S at the center point B of the sheet width, an end point A in the sheet width direction near one end surface, and the other end surface. The thickness of the plate at the end point C in the width direction of the plate is simultaneously measured and the measured plate thickness is output to the thickness calculator 2.

Reference numeral 3 denotes a scanning thermometer for measuring the temperature profile of the hot rolled steel sheet S in the sheet width direction. The scanning thermometer 3 has a scanning angle such that the entire width of the hot-rolled steel sheet S is included in its field of view, uses a solar cell as a detection element, and measures the width of the hot-rolled steel sheet S. The temperature profile in the direction (see FIG. 2) is output to the thickness calculator 2 at predetermined intervals. Reference numeral 4 denotes a radiation thermometer as a thermometer for measuring the temperature at the center of the sheet width, which measures the temperature at the center point B of the sheet width as a reference measurement point for temperature measurement of the hot rolled steel sheet S. The radiation thermometer 4 outputs its temperature measurement value to the thickness calculator 2.

The thickness calculator 2 calculates the thickness of the hot rolled steel sheet S at the center point B of the sheet width and the end points A and C in the sheet width direction obtained by the three-head radiation thickness gauge 1 according to a predetermined standard according to the procedure described later. The plate thicknesses at the respective plate thickness measurement points A, B, and C corrected to the values at a predetermined reference temperature are output to the recorder 5.

The procedure for measuring plate thickness will be explained below. When a temperature profile as shown in FIG. 2 is given from the scanning thermometer 3, the following steps are performed in the thickness calculator 2. First, the temperature values at the center point B in the strip width direction and the end points A and C in the strip width direction are sampled from the temperature profile data, and from these temperature values, the temperature difference between the edge point A in the strip width direction and the center point B in the strip width direction is sampled. ΔTA and the temperature difference ΔTC between the end point C in the board width direction and the center part B in the board width direction are calculated (calculated). in this case,
In the example shown in FIG. 2, the temperature values ΔTA and ΔTC are negative values.

Next, from the above temperature difference ΔTA and the temperature value TB measured at the board width center point B by the radiation thermometer 4, the temperature TA at the end point A in the board width direction is calculated as TA = TB + ΔTA
Calculate by calculating. Similarly, the temperature TC at the end point C in the board width direction is calculated by TC = TB + ΔTC.

Then, based on this calculated temperature value TA, the plate thickness at the end point A in the plate width direction, which is the plate thickness measurement point obtained by the three-head radiation thickness meter 1, is corrected to the value at a predetermined reference temperature. , the plate thickness at the end point A in the plate width direction at a predetermined reference temperature is determined. Similarly, based on the calculated temperature value TC, the thickness of the sheet at the end point C in the sheet width direction measured by the three-head radiation thickness gage 1 is corrected to the value at a predetermined reference temperature. Find the plate thickness at the reference temperature. In addition, the plate thickness at the plate width center point B is corrected to the value at a predetermined reference temperature based on the temperature measurement value TB at the plate width center point B by the radiation thermometer 4, and the plate thickness at the plate width center point B is adjusted to a value at a predetermined reference temperature. Find the thickness. Such a procedure is repeated, and the thickness of the hot rolled steel sheet S at the center point and both end points in the width direction of the hot rolled steel sheet S is continuously measured along the longitudinal direction of the hot rolled steel sheet S. Become.

As described above, from the temperature profile data in the width direction of the hot rolled steel sheet S obtained by the scanning thermometer 3, the temperature difference ΔT between the end point A in the sheet width direction and the center point B in the sheet width direction is determined.
A, and the temperature difference ΔTC between the end point C in the board width direction and the center point B in the board width direction is calculated, so the error due to individual differences in thermometers is not included. Since the temperature difference is relative to the end points A and C, even if the sensitivity of the scanning thermometer 3 changes over time, the effect is extremely small and the temperature difference ΔTA, ΔTC shows an accurate value.
is obtained.

[0020] These temperature differences ΔTA and ΔTC
and the temperature measurement value TB at the center point B of the sheet width measured by the radiation thermometer 4, and the end point A of the hot rolled steel sheet S in the sheet width direction.
, C, the calculated temperature value TA, which indicates the accurate value at the end points A and C in the sheet width direction, is calculated.
TC is obtained. As a result, this calculated temperature value TA
, TC and the temperature measurement value TB at the center point B of the plate width, the plate thickness at each measurement point obtained by the 3-head radiation thickness gauge 1 is corrected to the value at a predetermined reference temperature. Correction errors based on temperature are eliminated, and the thickness of the hot-rolled steel sheet S at the center point B of the sheet width and the end points A and C in the sheet width direction can be accurately measured.

[0021] In this embodiment, the center point B of the plate width was set as the reference measurement point for temperature measurement to measure the plate thickness, but the reference measurement point was set to the thickness measurement point A at the end in the width direction of the plate, or Even if the plate thickness is measured at point C, the plate thickness at the plate width center point B and the plate width direction end points A and C of the hot rolled steel plate S can be similarly accurately measured with high precision. .

A specific measurement example will be introduced below. According to the plate thickness measuring method according to the present invention, the plate thickness of the hot rolled steel plate at the plate width center point B and the plate width direction end points A and C is measured over a predetermined length along the longitudinal direction, and the average value thereof is determined. Ta. Thickness measurement points A and C at the ends in the sheet width direction were located 100 mm inward from the end surfaces of the steel sheets. In addition, in order to evaluate the accuracy of plate thickness measurement, cold plate thickness measurements were performed using an ultrasonic thickness meter.

The measurement results show that according to the method according to the present invention, the center point B is 25.46 mm, and one end point A is 25.46 mm.
25.30mm, the other end point C is 25.33mm, and the center point B is measured by a cold ultrasonic thickness gauge.
was 25.48 mm, end point A was 25.32 mm, and end point C was 25.36 mm. The measured values of both plate thicknesses were in good agreement, and it was confirmed that the method according to the present invention can accurately and accurately measure the plate thickness.

[0024]

As explained above, in the method for measuring the thickness of a hot-rolled plate according to the present invention, the thickness of the hot-rolled plate can be measured at either one of the center point in the width direction and the points at both end points in the width direction of the hot-rolled plate. point as the reference measurement point for temperature measurement, and from the temperature profile data in the width direction of the hot rolled plate material obtained by the scanning thermometer, the temperature difference between one plate thickness measurement point and the reference measurement point, and Since the temperature difference between the other plate thickness measurement point and the reference measurement point is determined, errors due to individual differences between thermometers that would occur if each plate thickness measurement point was measured with an individual thermometer are not included. Moreover, since it is a relative temperature difference, even if the sensitivity of the scanning thermometer changes over time, the effect of this change is extremely small, and a temperature difference that shows an accurate value can be obtained. Then, from these two temperature differences and the temperature measurement value of the reference measurement point measured by the reference point thermometer, the temperature of the other two plate thickness measurement points other than the reference measurement point is calculated. Therefore, calculated temperature values indicating accurate temperature values at the other two plate thickness measurement points can be obtained.

[0025] As a result, the calculated temperature values at the two thickness measurement points in the width direction of the hot-rolled plate obtained in this manner and the temperature measurement value at the reference measurement point, which is the other thickness measurement point, are calculated. By correcting the plate thickness at each plate thickness measurement point obtained by a radiation thickness meter to the value at a predetermined reference temperature based on The thickness of the plate at the center point and both end points in the width direction can be accurately measured.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an apparatus for implementing the method according to the invention.

FIG. 2 is a diagram for explaining the temperature profile of a hot rolled steel sheet obtained by a scanning thermometer according to the method according to the present invention.

[Explanation of symbols]

Claims (1)

[Claims] Claim 1: Based on the temperature measurement value of the hot rolled plate material measured using a thermometer, the central point and both ends of the hot rolled plate material in the width direction of the hot rolled plate material obtained by simultaneous measurement using a radiation thickness meter. In the method of correcting the plate thickness at a point to a value at a predetermined reference temperature and measuring the plate thickness at the three thickness measurement points of a hot-rolled plate material, the temperature profile in the width direction of the hot-rolled plate material is measured by scanning temperature. Temperature profile data obtained by measuring the temperature using a thermometer for reference point temperature measurement using any one of the plate thickness measurement points as a reference measurement point, and using the scanning thermometer. From this, the temperature difference between one plate thickness measurement point and the reference measurement point, and the temperature difference between the other plate thickness measurement point and the reference measurement point are determined, and these temperature differences and the temperature difference between the reference point temperature measurement thermometer and the temperature difference between the other plate thickness measurement point and the reference measurement point are determined. Calculate the temperature at two thickness measurement points other than the reference measurement point of the hot rolled plate from the temperature measurement value at the reference measurement point, and calculate the calculated temperature values at the two thickness measurement points other than the reference measurement point. By correcting the plate thickness at each plate thickness measurement point obtained by the radiation thickness meter to the value at a predetermined reference temperature based on the temperature measurement value at the reference measurement point and the temperature measurement value at the reference measurement point, A method for measuring the thickness of a hot-rolled plate material, the method comprising measuring the thickness at a center point and both end points in the width direction of the plate.