JPH0424121B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to dimensional control of circular cross-section strips such as round bars and wires.

In rolling round rods and wire rods, a groove die is used, and a plurality of rolling mills apply rolling reductions alternately horizontally and vertically to produce finished dimensions close to perfect circles. Here, the dimensions (cross-sectional shape) of the rolled material are almost determined by the rolling force of the final stage rolling mill, so the hole shape of this rolling mill is extremely precisely machined and replaced for each product size. However, in the case of groove rolling, as shown in Figure 1, the dimensions of points A and A that contact the bottom of the groove (hereinafter referred to as vertical dimensions) change depending on the amount of roll gap, and the dimensions of the free surface that is not constrained by the groove. B,B
(hereinafter referred to as width dimension) also changes. FIG. 1a shows the case when the rolling reduction is proper, FIG. 1b shows the case when the roll gap is too large, and FIG. 1c shows the case when the roll gap is too small.

As rolling progresses further and the rolls wear out, the cross-sectional shape of the product changes. That is, the portion X called the shoulder of the roll in FIG. 2 is worn the most due to the flow of meat due to rolling by the rolling mill, and therefore the dimension of this shoulder portion (hereinafter referred to as shoulder dimension) has the largest value. Although the exact position of this shoulder dimension cannot be specified, it is usually located around 30° from the width dimension. Figure 3 shows the cross-sectional shape of an 80° bar.
This is a plot of the diameter measured every 5 degrees with a micrometer, and the shoulder dimension can be clearly identified. The areas between these two protruding shoulders C, C or C', C' are the free surfaces D, D', and the areas orthogonal to these free surfaces are the top and bottom E, E. Generally, the cross section of a round bar has a shape as shown in Figure 3, with the shoulder dimension being the maximum value and either the top, bottom or width dimension being the minimum dimension, or the width dimension being the maximum as shown in Figure 1 c. It will be sorted in one of the following cases.

However, with conventional rolling lines, it is impossible to know the cross-sectional shape of such rolled strips, and the only methods available are sampling inspections that measure cut samples or inspections of products that have been sheared after cooling using limit gauges or micrometers. Ta.

In recent years, with advances in electronics, attempts have been made to measure the dimensions of the round bar by installing a photoelectric dimension measuring device at the rear (downstream) of the rolling mill, and to control the dimensions by operating the rolling mill's rolling device based on this measurement. being done. For example, there is a method as shown in Japanese Patent Publication No. 50-39066 and 55-39067 in which the height and width dimensions are measured to control the rolling reduction or tension of the two upstream rolling mills, but since the rolled strip is twisted after rolling, Even if an optical dimension measuring device with two orthogonal axes was installed in correspondence with the rolls of a rolling mill, there was a drawback that it was not always possible to measure the vertical and width dimensions. Furthermore, even if the height and width dimensions can be measured, as mentioned above, the maximum dimension is often the shoulder dimension, so there is a problem that simply controlling the height and width dimensions cannot reliably contribute to the dimensional accuracy of the product. Ta.

The present invention was developed in view of the drawbacks of the conventional method, and uses a high-precision continuously rotating dimension measuring device to measure the cross-sectional shape, identify the top, bottom, width, and shoulder dimensions, and then determine the predetermined relationship. This method aims to improve the overall dimensional accuracy of the strip by correcting the rolling reduction of the final stage using the formula, and by detecting and predicting the rolling temperature, which has a large effect on dimensional fluctuations.

The method for controlling the size of a round bar according to the present invention includes installing a strip size measuring device that rotates around the rolled material on the exit side of a row of continuous rolling mills using grooves, and measuring the cross-sectional shape of the strip using the output of the measuring device. In this cross-sectional shape, the angular position where the steepest change occurs is defined as the width position, the angular position perpendicular to the angle is defined as the vertical position, or the angular position where the change is the gentlest is defined as the vertical position, and the angular position orthogonal to that is defined as the width position. The maximum diameter of the cross-sectional shape excluding the width and top and bottom positions is taken as the shoulder diameter, and the deviations ΔB ₀ , ΔH ₀ , and ΔL ₀ from the target values of the width, top and bottom, and shoulder diameter are determined, and these are shown in Figure 9. From the relationship between the rolling reduction change of the most downstream rolling mill and the width, top/bottom, and shoulder diameter changes, use formulas (6), (7), and (8) to determine the target values for the width, top/bottom, and shoulder diameter when adding rolling reduction changes. The present invention is characterized in that the reduction in which the maximum value of these three deviations becomes the minimum is controlled by calculating the predicted deviation of these three deviations.The configuration of the present invention will be described in detail below.

FIG. 4 shows a rotating rod and wire rod dimension measuring device used when carrying out the method of the present invention, in which light emitted from a light source 2 passes through a lens 3 and becomes a parallel ray, and the shadow of the rod and wire rod is reflected by a light receiving lens. 4 and is imaged onto the photoelectric conversion array element 5. A charge coupled device is used for the photoelectric conversion array element 5. This image is outputted from the array element 5 in the form of a pulse train corresponding to brightness and darkness by pulses applied from the transmitter 6.
It is counted by counter 7. The diameter of the rod and wire rod converted into pulse counts is input to the calculation device 9.
Here, the pulse train is transmitted through the slip ring 8. The output of the angle detector 13 is also input to the arithmetic unit 9 in order to recognize at which angle the diameter is measured with respect to the vertical of the wire rod.

FIG. 5 is a three-dimensional view of this dimension measuring device, and the light source 2, lenses 3, 4, array element 5, and slip ring 8 in FIG. 4 are integrally attached to the rotating body 12. It is continuously rotated in a fixed direction by a motor 10 around a fixed shaft 11. Similarly to the input of the pulse signal to the rotating body 12, the rotating body 12
The light/dark signal is transmitted through the slip ring 8, and since the rotating body 12 rotates at 45 revolutions per minute, it takes 0.66 seconds, which is the time it takes for the rotating body to rotate 180°, to measure one cross section of the wire rod. It takes. An angle detector 13 in FIG. 4 generates a signal indicating the rotation angle from the reference angle and this 180° rotation. The diameter of the rod and wire rod 1 is measured every time the rotating body rotates by 6 degrees, and diameter values at a total of 30 points are input to the calculation device 9 in half a rotation. Examples of such rotary dimension measuring devices include Utility Application No. 53-20271, Utility Model Application No. 53-23729, and Japanese Patent Application No. 160952-1989, which are currently being filed by the inventors of the present application.

Now, the cross-sectional shape of the rod and wire material according to the 30 diameter values is displayed graphically by the computing device 9 as shown in Fig. 3, but at the same time it is also displayed on the time axis as shown in Fig. 6 using a recorder (not shown). is output to. As a result of investigating many patterns of the diameter of one cross section on the time axis, it was found that the point where the diameter value changes most steeply corresponds to the free surface. Therefore, in Fig. 6, point (a) is the width dimension, and the diameter at the angle (b) perpendicular to this is the top and bottom diameter. Furthermore, among this width and the diameter near the top and bottom, the largest angle (c) that is close to the width dimension corresponds to the shoulder dimension. These width, top and bottom, and shoulder angles are correlated with the signals from the angle detector shown in Figure 4, but if the rod or wire material is twisted, the correspondence with the angles corresponding to the top, bottom, and width of the roll may not be perfect. . In addition, when identifying the width dimension, it is also possible to use the diameter that has the maximum deviation from the sine wave. Furthermore, since the top and bottom portions of the roll undergo little wear and tear, it is also effective to find a portion of the roll that matches the known curvature of the hole shape and use its center as the top and bottom diameter. In other words, the difference between the 30 diameters may be taken and the point with the smallest change in the difference sequence may be taken as the top and bottom. In this way, when the top and bottom diameters H ₀ , width diameter B _{0 ,} and shoulder diameter L ₀ are determined, the deviations from the target diameter D ₀ are found, ΔH ₀ , ΔB ₀ , and ΔL _{0 ,} respectively. It is also known that one of them has the minimum diameter, so these deviations ΔH ₀ ,
By reducing the absolute values of ΔB ₀ and ΔL ₀ , the dimensions of the strip become closer to the target diameter D ₀ and accuracy can be improved. Next, the dimension control method will be explained.

FIG. 7 shows the upper half of the cross section of the roll hole mold and the rod and wire rod. The hole shape of the roll is ground so that it has a reference radius R ₀ with P ₀ as the center when the reference gap d ₀ is set.
At this time, if the spring-up due to the rolling load of the roll gap is ignored, the cross section of the rod and wire rod is 7th.
It has a shape like the diagonal line in the figure, and matches the roll shape on the top and bottom, but on the free surface, the part that is not restrained by the roll differs from the reference radius R ₀ . Now, in Fig. 7, if we consider that the gap of the roll increases by Δ from d ₀ , the center of the cross section on one side moves to P′ of d ₀ +Δ/2, and the top-to-bottom diameter becomes 2R ₀ +Δ, and Δ However, for other diameters, if the angle from the top and bottom diameters is θ, Since R ₀ >>Δ/2, equation (1) is D(θ)=2R ₀ +(1+D(Δ/2R) ² +Δ/R ₀ cosθ
) 2/ 1 ≒2R ₀ + (1+1/2Δ/R ₀ cosθ) = 2R ₀ +Δcosθ ……(2), and only Δcosθ becomes large.

Therefore, the shoulder diameter is on the width dimension side, and from the top and bottom diameter
Since it is about 60°, even if the reduction amount changes by Δ, it will only change by 0.5Δ.
only changes. This relationship is shown in Figure 8a. In FIG. 8, the vertical axis shows shoulder diameter change ΔL or width diameter change ΔB, and the horizontal axis shows reduction correction amount ΔS.

On the other hand, since the width dimension is not restricted by the diameter roll, the top and bottom of the rolling mill one upstream corresponds to the free surface of the rolling mill, so the rolling reduction of the rolling mill one upstream is dominant. However, when the groove is properly filled with meat, if the roll gap of the final rolling mill is made smaller, the meat escapes in the width direction and the width becomes larger.On the other hand, if the gap is made larger, the meat becomes insufficient and the width becomes smaller. becomes smaller. This relationship is shown in FIG. 8b, and the change in the width dimension is small compared to the amount of change Δ in the rolling reduction and reaches saturation. From this it can be seen that the width dimension can be roughly corrected in the rolling mill one upstream, and fine corrections can be made in the final rolling mill. Therefore, from the output of the above-mentioned bar and wire dimension measuring device, the deviations of the height, width, and shoulder dimensions from the target diameter are ΔH ₀ , ΔB ₀ ,
If ΔL ₀ is known, the necessary reduction correction amount can be determined. FIG. 9 shows the relationship when ΔH, ΔB, and ΔL are variously changed, with the vertical axis representing the dimensional deviation and the horizontal axis representing the reduction correction amount.

First, as shown in Figure 9a, if the shoulder deviation is large, followed by the top, bottom, and width, the shoulder angle θ should be 60°, the shoulder diameter change rate with respect to the reduction change should be 0.5, and the width change rate should be 0.33.
If the reduction ΔS is corrected in the negative direction by ΔS ₀ , the shoulder and top deviations will be equal and the width deviation will be zero, at which point the dimensional deviation will be the smallest. Figure 9b shows a case where the vertical deviation is large, followed by the shoulder and width, but in this case too, by moving ΔS negatively, the deviation becomes minimum at point P where the vertical deviation and the width deviation are equal. Next, the roll reduction is too large and the width deviation is the largest, and then the shoulders and the _top and bottom. At this time, the deviation is minimum. However, Fig. 9d
If the width dimension is extremely small _as in
Rather than correcting and minimizing the deviation at point P, by increasing the rolling gap of the rolling mill one upstream, the width dimension at that rolling mill is increased and the width deviation is set to ΔB ₀ '. After that, when the rolling mill reduction is corrected by ΔS ₀ ', the deviation becomes minimum at point P', and the deviation becomes smaller. If the width dimension deviation is large as in this case, the width dimension change straight line will become saturated when the rolling reduction changes excessively as shown in Figure 8b, making it difficult to determine the optimum rolling reduction correction amount.Therefore, the rolling reduction correction should be made as small as possible. It is more accurate and the deviation can be reduced.

As explained above, when the rolling reduction correction amount ΔS of the final rolling mill is small, the vertical change ΔH, shoulder change ΔL, and width change ΔB are calculated as follows: ΔH=ΔS ...Equation (3) ΔL=ΔScosθ θ=60° to 70° ...Equation (4) ΔB=A・ΔS ...It can be approximated linearly with Equation (5), so the height, shoulder,
If the width deviations ΔH ₀ , ΔL ₀ , and ΔB ₀ are known, ΔS that minimizes the maximum value of each deviation (absolute value) can be found as (3), (4), (5)
Using ΔH=ΔH ₀ +ΔS ...Equation (6) ΔL=ΔL ₀ +ΔS・cosθ ...Equation (7) ΔB=ΔB ₀ +A・ΔS ......Equation 2 of the left side of the three equations in Equation (8) Find ΔS where the two absolute values are equal, determine the maximum value by including the absolute value of the remaining one equation, do this for three combinations of the three equations, and select the one with the smallest maximum value. The solution ΔS at that time is the optimal solution. In this case, cos θ and A are constants determined and memorized in advance for each size of rod and wire rod, but the above-mentioned dimension measuring device measures the changes in the vertical, shoulder, and width dimensions when the rolling reduction is changed by ΔS during the control process. From this, these constants may be modified as appropriate. Further, when the temperature of the rolled strip material changes, the width spread characteristic changes as shown in FIG. 10. In this figure, the roll gap of the rolling mill is fixed, but in reality the deformation resistance changes, so if the rigidity of the rolling mill is small, the roll gap will change by ΔF/M due to the change in rolling load ΔF, assuming the mill constant is M. Change.
Therefore, the change in width dimension ΔB〓 _T as shown in Fig. 10 due to the change in rolling temperature ΔT is ΔB〓 _T = C・ΔT (C<O) ......The change in width due to not only the formula (9) but also the change in rolling reduction ΔF/M ΔB=C・ΔT+A・ΔF/M...Equation (10) is obtained, but what can actually be observed is statistically based on numerous data of width change ΔB, temperature change ΔT, and pressure change ΔF according to equation (10). The coefficients C and A can also be determined. In this case, it is preferable not to intentionally change the rolling force of the rolling mill from the outside, and the rolling force change ΔF may be actually measured using a load cell, but the mathematical model
It's better to predict. Therefore, when the rolling temperature changes by ΔT, the dimensional deviations of top, bottom, shoulder, and width are (6),
(7) and (8) are the mill spring up change ΔF/M and (10)
Equations (11), (12), and (13) are obtained by considering Eq.

ΔH=ΔH ₀ +ΔF/M+ΔS...Equation (11) ΔL=ΔL ₀ +(ΔF/M+ΔS) cosθ...Equation (12) ΔB=ΔB ₀ +A(ΔF/M+ΔS)...Equation (13) These equations also (6), (7), shown similarly to Figure 8.
Using exactly the same procedure used to determine the optimal reduction correction amount ΔS from equation (8), solve the simultaneous equations in which the absolute values of any two equations (11), (12), and (13) are equal, and then The maximum value may be found together with the absolute value of one equation, and ΔS where the maximum value is the smallest among these may be used as the optimal solution. The reduction is corrected based on these optimal solutions while checking the correction results with a dimension measuring instrument, so the response of the rolling motor and the transport delay time to the dimension measuring instrument are taken into consideration to ensure that one rolled strip is corrected.
It is performed 10 to 20 times. Furthermore, a thermometer for detecting the temperature of the rolled strip is provided on the entry side of the rolling mill, and the measured temperature is also delayed by the time it takes to reach the rolling mill.

As described above, according to the method of the present invention, the deviation output indicated by the dimension measuring instrument is reduced by the reduction correction, and the dimensional accuracy is improved.
According to this method, it is possible to manufacture rods and wires with extremely precise dimensional accuracy, and has great effects such as eliminating the need for a drawing process at the customer.

[Brief explanation of drawings]

Figure 1 is a diagram showing the relationship between the roll gap and the shape of the rolled material, Figure 2 is an explanatory diagram of roll wear and the shape of the shoulder, Figure 3 is a diagram showing the shape of the bar cross section, and Figure 4 is a diagram of the principle of the dimension measuring instrument. , Figure 5 is a three-dimensional view of the dimension measuring instrument, Figure 6
The figure is a graph showing the relationship between the time axis and the cross section, Figure 7 is a diagram of the roll hole type and the upper half of the rod and wire cross section, Figure 8 is a diagram showing the reduction correction amount and the rate of change in shoulder diameter, and Figure 9 is a graph showing the relationship between the time axis and the cross section. FIG. 10 is a diagram showing the relationship between the amount of reduction correction and each deviation of the top, bottom, width, and shoulder, and FIG. 10 is an explanatory diagram of the relationship between temperature and width spread. 1...Wire rod, 2...Light source, 3...Lens, 4
... Light receiving lens, 5 ... Photoelectric conversion array element, 6
...Transmitter, 7...Counter, 8...Slip ring, 9...Arithmetic device, 10...Motor, 11...
... Fixed axis, 12 ... Rotating body, 13 ... Angle detector.

Claims (1)

[Claims] 1. A strip dimension measuring device that rotates around the rolled material is provided on the exit side of a row of continuous rolling mills using grooves, and the cross-sectional shape of the strip is determined by the output of the measuring device, and the cross-sectional shape of the strip is determined by the output of the measuring device. The angular position where the shape changes most steeply is the width position, the angular position perpendicular to this angle is the vertical position, or the angular position where the change is the gentlest is the vertical position, and the angular position perpendicular to the vertical position is the width position, and the width of this The maximum diameter of the cross-sectional shape excluding the top and bottom positions is taken as the shoulder diameter, and the deviations ΔB ₀ , ΔH ₀ , and ΔL ₀ from the target values of the width, top and bottom, and shoulder diameter are determined respectively, and the rolling correction amount of the most downstream rolling mill is calculated from these. After adding ΔS, calculate the deviations ΔB, ΔH, and ΔL from the target values of the width, top and bottom, and shoulder diameter using the following formulas, and calculate the deviations such that the maximum value of these deviations ΔB, ΔH, and ΔL is the smallest. A dimensional control method for a round bar, characterized in that the roll gap is controlled by determining the reduction correction amount ΔS. ΔB=ΔB ₀ +A・ΔS ΔH=ΔH ₀ +ΔS ΔL=ΔL ₀ +ΔS・cosθ Here, A is the rate of change in width, and cosθ is a trigonometric function representing the rate of change in shoulder diameter, which is determined in advance for each size of rod and wire and stored. is a constant. 2. Install a surface thermometer for the rolled material on the entrance side of the rolling mill,
The dimensions of the round bar according to claim 1, wherein the rolling force change ΔF is calculated from the measured rolling temperature change ΔT, and the following formula is used instead of the calculation formula set forth in claim 1. Control method. ΔB=ΔB ₀ +A(ΔF/M+ΔS) ΔH=ΔH ₀ +ΔF/M+ΔS ΔL=ΔL ₀ +(ΔF/M+ΔS)cosθ Here, M is a Mill constant determined and memorized in advance. 3. Claim 1 or 3, characterized in that the formula for determining the deviation from target values of the width, top and bottom, and shoulder diameter after correction of rolling mill reduction is corrected based on the output of a strip size measuring device, or The method for controlling the dimensions of a round bar according to item 2. 4. A round bar control method according to any one of claims 1 to 3, characterized in that the rough correction of the width dimension is performed at a rolling mill one upstream from the most downstream rolling mill.