JPS58218314A - Method for controlling dimension of round bar - Google Patents

Abstract

PURPOSE:To improve the comprehensive dimensional accuracy of a bar material, by using a measuring instrument for measuring a cross-sectional shape of the bar, and respectively recognizing vertical, horizontal, and diagonal dimensions of it for correcting the rolling reduction of a rolling mill at the final stage. CONSTITUTION:An angle detector 13 outputs the signals of an angle rotated from a standard angle and an angle rotated by 180 deg. from the rotated angle. The values of diameters of a wire rod material are detected at 30 points while the bar is rotated by a half revolution, and are inputted to an arithmetic device 9. When a vertical diameter H0, a horizontal diam. B0 and a diagonal diam. L0 are obtained, the deviations DELTAH0, DELTAB0, and DELTAL0 between said diameters and a target diam. D0 are also obtained. By using the relation between the change of rolling reduction of the last mill on the downstream which is previously obtained and the changes of horizontal, vertical and diagonal diameters, the changing quantities of horizontal, vertical and diagonal diameters obtained by adding the change of rolling reduction are added to said deviations, to calculate the estimated deviation from respective target values. The dimensions of the round bar are controlled by controlling the rolling reduction so that the maximum value of these three deviations becomes minimum.

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 rod wire rods, a hole die is used, and a plurality of rolling mills alternate horizontally and vertically, and rolling is applied to produce a finish close to a perfect circle with nine dimensions. The dimensions (cross-sectional shape) of the rolled material
Since #1 is determined by the rolling of the final stage rolling mill, the hole shape of this rolling mill is processed with extremely high precision and replaced for each product size. However, in the case of groove rolling, as shown in FIG. 1, the point A is in contact with the bottom of the groove depending on the roll gap.

The dimension A (hereinafter referred to as the vertical dimension) changes, and the dimensions B of the free surface not constrained by the hole shape (hereinafter referred to as the width dimension) also change. Figure 1 (a) shows that when the pressure is properly applied, (b)
) is the case when the roll gap is too large, and (C) is 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 usually exists around 30 degrees from the width dimension. Fig. 3 shows the cross-sectional shape of the 80 mm square, and plots the diameter measured every 5 degrees using a micrometer, and the size of the debris 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. In general, the cross section of a round bar is shaped 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, and the other cases are as shown in Figure 1 (,).
It is sorted in one of the cases where the width dimension is maximum, such as.

However, with conventional rolling lines, it is impossible to know the cross-sectional shape of such rolled strips, and sampling inspections that measure cut samples or inspections of sheared products after cooling with a limit gauge or micrometer are required. That's all I could do.

Due to advances in electronics in recent years, a photoelectric dimension measuring device is installed at the rear (downstream) of the rolling mill to measure the dimensions of the round bar.
Based on this, attempts have been made to control the dimensions by operating the reduction device of the rolling mill.

For example, there is a method as shown in Japanese Patent Publication No. 50-39066.5O-3906=7 in which the height and width dimensions are measured and the rolling or tensioning of the two upstream rolling mills is controlled, but the rolled strip is Since it is twisted, it is perpendicular to the roll of the rolling mill.
Even if an optical shaft dimension measuring device was provided, there was a drawback that it was not always possible to measure the vertical and width dimensions. Also, even if it is possible to measure the top, bottom, and width dimensions of a round toe, as mentioned above, the maximum dimension is often the shoulder dimension, so simply measuring the top, bottom, and width dimensions cannot reliably contribute to the dimensional accuracy of the product. I have a problem.

The present invention was developed in view of the drawbacks of the conventional method.The present invention measures the cross-sectional shape using a high-precision continuously rotating dimension measuring device, identifies the top, bottom, width, and shoulder dimensions, and then calculates a predetermined relational formula. When the final stage rolling mill reduction is corrected using this method, the overall dimensional accuracy of the strip is improved by detecting and predicting the rolling temperature, which has a large effect on dimensional fluctuations.

The configuration of the present invention will be explained in detail below.

FIG. 4 shows a rotary type measuring device for rod and wire rod dimensions 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 parallel rays, and the shadow of the rod and wire rod is The light passes through the 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 output from the array element 5 in the form of a pulse train corresponding to brightness and darkness by pulses applied from the oscillator 6, and is counted by the counter 7. The diameter value of the rod and wire rod converted into a pulse count is inputted to the calculation device 9. Here the pulse train is transmitted through the slip ring 8. The position of the angle detector 15 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. Oshi,
It is continuously rotated in a fixed direction by a motor 10 around a fixed shaft 11. Similar to the pulse signal input to the rotating body 12, the bright/dark signal from the rotating body 12 is performed via the slip ring 8), and since the rotating body 12 rotates at 45 revolutions per minute, the rod and wire rods are A rotating body of 180 mm is used to measure the cross section.
It takes 66 seconds to turn [L66 seconds]. The angle detector 13 shown in FIG. 4 generates a signal of the rotation angle from the reference angle and this 180° rotation. The diameter of rod wire 1 is measured when the rotating body is 6.
This is done every six revolutions, and a total of 30 diameter values are input to the arithmetic unit 9 in half a revolution.

As such a rotary dimension measuring device, Utility Application No. 55-20271 and Utility Application No. 53-237 currently filed by the present inventors are known.
No. 29, Japanese Patent Application No. 160952/1984, etc.

Now, the cross-sectional shapes of the rods and wires based on the 30 diameter values are displayed graphically by the calculation device 9 as shown in Figure 3.
At the same time, the signal is also output to a recorder (not shown) as shown in FIG. 6 on the time axis. 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 value obtained by differentiating the diameter value with respect to time or angle is maximum corresponds to the 7 Lie plane, that is, the medium dimension. Therefore, in FIG. 6, point (a) is the width dimension, and the diameter at the angle (b) perpendicular to this is the vertical diameter. Furthermore, among this width and the diameter near the top and bottom, the largest angle 6 close to the width dimension corresponds to the shoulder dimension. These width, top and bottom, and shoulder angles, = 6, correspond to the signals from the angle detector shown in Figure 4, but if the wire rod is twisted, the correspondence with the angles corresponding to the top, bottom, and width of the roll is not perfect. Sometimes. In addition, when identifying the width dimension, it is also possible to use the diameter that has the maximum deviation from the sine wave. It is also effective to find a portion that matches the known curvature of the hole shape of the roll and use its center as the top and bottom diameter. That is, the difference between the 30 diameters may be taken, and the point with the smallest change among the differences may be taken as the top and bottom. In this way, the top and bottom diameter HOs width diameter is 8 degrees, and the shoulder diameter is 8 degrees. When you ask for it, the target diameter is reached.

It is also known that the minimum diameter is either the top diameter H0 or the middle diameter B0, so if the absolute values of these deviations ΔH0 and ΔBO+ΔL0 are reduced, The dimensions of the strip become close to the target diameter D0, 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 rod and wire rod.

The roll 4'l hole type is ground so that when the standard clearance is do, the standard radius is 21: with po as the center. If the spring-up due to the rolling load in the roll gap is ignored at this angle of 11°, the cross section of the rod and wire rod will be shaped like the diagonal line in Figure 7.It matches the roll shape in the vertical direction, but is constrained by the roll in the free surface. The part that is not set is different from the reference radius &. Now, in Fig. 7, if we consider the case where the roll gap increases from do to d, +Δ, the center of the cross section moves to P' of do + j on one side, and the top-to-bottom diameter becomes 2R, +Δ, which increases by Δ. However, for other diameters, if the angle from the top and bottom diameter is θ = 2Ro + Δeos a ==
Equation (2) is obtained, and Δcotse does not become large.

Therefore, the shoulder diameter is on the rear side of the width dimension and is 60'' from the top and bottom diameter.
Therefore, even if the rolling reduction amount changes by Δ, it will only change by 0.5Δ. This relationship is shown in FIG. 8(a). In Figure 8, the vertical axis shows shoulder diameter change ΔL or middle diameter change ΔB, and the horizontal axis shows pressure and
It is expressed by taking the downward correction amount ΔS.

On the other hand, since the width dimension is not directly constrained by the rolls, the top and bottom of the rolling mill one upstream corresponds to the IJ-plane of the rolling mill, so that 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 increases. Dimensions become smaller. This relationship is shown in FIG. 8(b), and the change in the width dimension is small compared to the amount of change Δ in the rolling reduction and is saturated. From this it can be seen that the width dimension can be roughly corrected at the rolling mill one upstream, and fine corrections can be made at the final rolling mill. Therefore, if the deviation ΔHO9ΔBesΔL0 of the vertical, width, and shoulder dimensions from the target diameter is known from the output of the above-mentioned bar and wire dimension measuring device, the necessary reduction correction amount can be determined. FIG. 9 shows the relationship when ΔH9ΔB and ΔL vary variously, with the vertical axis representing the dimensional deviation and the horizontal axis representing the reduction correction amount.

First, as shown in Figure 9(a), the shoulder deviation is large, followed by the top and bottom.
If the width is the same, the shoulder angle θ is 60°, the rate of change in waste with respect to the change in roll is 0.5, the corrosion rate is 0.33, and if the roll reduction ΔS is corrected by ΔS0 in the negative direction, the deviation between the shoulder and the top and bottom is equalized. , < and the width deviation becomes zero, at which time the dimensional deviation becomes the smallest. FIG. 9(b) shows a case where the vertical deviation is large, followed by the shoulders and width, but in this case as well, 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 excessive and the width deviation is 1, and the width deviation is the largest, followed by the shoulders and the top and bottom. are equal and in this case the deviation is the minimum.However, in Fig. 9 (d
) If the width dimension is extremely small, as in (1), correct the rolling reduction by ΔS0 to minimize the deviation at point P. By increasing the width bar in the rolling mill and making the width deviation ΔB0/, and then correcting the f:rolling reduction by ΔSo', the minimum deviation at point P' becomes 1(, shi, the deviation is smaller k If the deviation in the width dimension is large as in this case, the saturation phenomenon will occur when the width dimension changes as shown in Figure 8 (b), and the optimum reduction amount will be difficult to determine. It is more accurate to make the value as small as possible, and the deviation can be reduced.

As explained above, when the rolling reduction change ΔS of the final rolling mill is small, the vertical change ΔH1 shoulder change ΔL1 width change Δ
For each B, Δ■=ΔS ・・・−・(3)
Formula ΔL=ΔS coBe θ=60°~75°
...--(4) Formula ΔB=A・ΔS
......Equation (5) can be approximated linearly, so if you know the deviations ΔHoeΔLo and ΔBe of the height, shoulder, and width from the target diameter, you can calculate Δ to minimize the maximum value of each deviation (absolute value).
S is (3), (4).

(ΔH using the average = ΔH0 + Δ level ・・・−・・(
6) Formula ΔL= ΔL0+ ΔS... eos #
・・・・・・(C formula ΔB=ΔB, +
A'iΔS...Find ΔS in which the absolute values of the left side 4' or two of the three equations in (8) are equal, and then determine the maximum value by including the absolute value of the one equation. If this is done for three combinations of the three equations and the one with the smallest maximum value is selected, the solution ΔS at that time becomes the optimal solution. In this case, +os e and A are constants calculated and memorized in advance for each size of rod and wire rod, but when the reduction is moved by ΔS during the control process, the change in each dimension of top, bottom, shoulder, and width can be measured using the above-mentioned dimension measurement method. These constants may be determined using a device and then modified as appropriate. Furthermore, when the temperature of the rolled strip material changes, the width spread characteristic changes as shown in FIG. In this figure, the roll gap of the rolling mill is fixed, but in reality the deformation resistance changes, so when rolling is performed and the rigidity of the mill is small, the number of mill lights is M due to the change in rolling load ΔF, then ΔF/M Only the roll gap will change. Therefore, the change ΔBΔi in the width dimension as shown in Fig. 10 due to the change ΔT in rolling temperature is 184 teeth=C・ΔT (C<O) -...
ΔB=c・ΔT+A・ΔF/M −・・・・
However, what can actually be observed is the width change ΔB, temperature change ΔT, and pressure change ΔF, which can be statistically determined based on a large amount of data. In this case, it is preferable that the rolling mill is not intentionally moved from the outside, and the change in rolling force ΔF may be actually measured using a load cell, or may be predicted from ΔT using a mathematical model. Therefore, when the rolling temperature changes by ΔT, the dimensional deviations of the top, shoulder, and width are as follows (6), (7), and (8), taking into account the mill spring-up change ΔF/M (<11),
H, (1m type.

ΔH=ΔH0+ΔF/M+J8...
・I formula ΔL=ΔL0+(ΔF/M+ΔB) toms
...-132 formula ΔB=ΔBo+A(ΔF/M+Δ
8) ・・−・−・(Equation 13 These expressions are also the 8th
The same procedure as shown in the figure (6) and (c) was used to determine the optimum rolling reduction amount ΔS1 from equation (8) (11>
, (13. Solve the simultaneous equations in which the absolute values of any two equations of am are equal, find the maximum value together with the absolute value of the remaining one equation, and calculate the case where the maximum value is the smallest among them. It is sufficient to use ΔB as the optimum solution.Since the correction of the reduction based on these optimum solutions is performed while checking the correction results with a dimension measuring instrument, the response of the reduction motor and the transportation delay time to the dimension measuring instrument are taken into consideration. This process is carried out 10 to 20 times on the same rolled strip.Furthermore, a thermometer to detect the temperature of the rolled strip is installed on the entrance side of the rolling mill, and the measured temperature corresponds to the time it takes to reach the rolling mill. be delayed.

As described above, it can be seen that 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. It is possible to manufacture rods and wires with 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 rolling gap and the shape of the rolled material.
The figure is an explanatory diagram of roll wear and shoulder shape, Figure 3 shows the shape of the bar cross section □-1 Figure 1 is a diagram of the principle of the dimension measuring instrument, Figure 5 is a three-dimensional diagram of dimensions, and Figure 6 is a time axis The relationship between the cross section and the cross section is =τ::F, Figure 7 shows the cross section of the hole type and rod wire rod:':
Figure 8 is a diagram showing the ratio of the amount of reduction correction and the change in shoulder diameter, Figure 9 is a diagram showing the relationship between the amount of reduction correction and each deviation of the top, bottom, width, and shoulder. FIG. 10 is an explanatory diagram of the relationship between temperature and width. 1: Rod wire 2: Light source 3: Lens 4: Light receiving lens
5: Photoelectric conversion array element 6: Transmitter 7: Counter 8
Nisri spring 9: Arithmetic unit 10: Motor -1
: Fixed shaft 12: Rotating body 13: Angle detector Applicant Nippon Steel Corporation Patent attorney Minoru Aoyagi 1,'7 □ Figure 8 t (C) □ Dimensions flal! (b) Dimension 3L rectangle 10th figure 800 900 1000'CT F
L En J” Written amendment of false procedure (voluntary) July 20, 1988 1, Display of the case 1982 Patent Application No. 100419 2, Name of the invention Method for controlling the dimensions of round bars & Person making the amendment Related Patent Applicant Address: 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name
(665) Nippon Steel Wire System Company Representative Takeshi 1) Yutaka 4, Agent 〒101 5, Date of amendment order None 6, Detailed explanation of invention increased by amendment, Paper (1) Specifications The scope of claims from page 1, line 5 to page 2, line 14 is amended as follows. (1) A strip size measuring device that rotates around the rolled material is installed on the exit side of the row of continuous rolling mills using the groove type, and the cross-sectional shape of the multi-strip material is determined from the output of the measuring device. The diameter that is most equal to the curvature of the hole shape is the top and bottom diameter, or the angular position where the change is the slowest is the top and bottom, and the angular position perpendicular to it is the width, and the maximum diameter of the cross-sectional shape excluding the top and bottom diameter is the shoulder,
Deviations from the target values for middle, top and bottom, and clearing, respectively, ΔBOsΔbird,
The amount of change in width, top and bottom, and clearance when Δ- is calculated, and reduction is added using the relationship between the rolling reduction change of the most downstream rolling mill and the change in width, top and bottom, and clearance, which are calculated in advance. of,,
A method for controlling the size of a round bar, comprising: calculating predicted deviations from respective target values; (2) The relational expression between the rolling reduction change of the rolling mill and the width, top and bottom, and scraping dimension changes is corrected based on the appearance of the strip dimension measuring device. Dimension control method for round bars. (3) The method for controlling the dimension of a round bar according to claim 1, characterized in that the rough correction of the width dimension is performed at a rolling mill one upstream from the most downstream rolling mill. (4) The method for controlling the dimension of a round bar according to claim 2, characterized in that the rough correction of the width dimension is performed in a rolling mill one upstream from the umbrella downstream rolling mill. (5) A thermometer was installed on the upstream side of the most downstream rolling mill to measure the rolling temperature of the strip, and changes in top and bottom dimensions, width dimensions, and layer diameter changes due to changes in rolling temperature were added to the predicted deviation from the target value. A method for controlling dimensions of a round bar according to claim 1, characterized in that: (2) The statement on page 7, lines 11-12: ``As a result of inspection, the point where the '11° diameter value changes by the steepest 1 corresponds to the free surface.''
Ratio 1□・(6) The information on page 9, line 7 of the same page is corrected to 1□. (4) Correct "shoulder" in line 10 of page 11 to "width".

Claims (1)

[Scope of Claims] (1) A strip size measuring instrument that rotates around the rolling mill is provided on the exit side of a row of continuous rolling mills using a groove type, and the cross-sectional shape of the strip is determined from the output of the measuring instrument; In this cross-sectional shape, the width is defined as the angular position where the steepest change occurs, and the diameter perpendicular to the angle is defined as the vertical diameter, or the angular position where the change is the slowest is defined as the angular position perpendicular to the vertical and vertical directions, and this width excludes the vertical diameter. The maximum diameter of the cross-sectional shape obtained is taken as the shoulder, and the deviations ΔBeeΔHowΔLO from the target values of the center, top, bottom, and shoulder diameters are calculated, and the changes in the width, top, bottom, and shoulder diameters are added to these and calculated from the respective target values. A method for controlling dimensions of a round bar, characterized in that the reduction is controlled to minimize the maximum value of these three deviations. (2) The relational expression between the rolling reduction change of the rolling mill and the dimensional changes of the width, top and bottom, and shoulder diameter is corrected based on the output of the strip dimension measuring device. Dimension control method for round bars. (3) The method for controlling the dimension of a round bar according to claim 1, characterized in that the rough correction of the width dimension is performed at the rolling mill one step upstream from the most downstream rolling mill. -(4) The method for controlling the dimension of a round bar according to claim 2, characterized in that the width dimension is roughly corrected by rolling the rolling mill upstream of the most downstream rolling mill. (5) A thermometer was installed on the upstream side of the most downstream rolling mill to measure the rolling temperature of the strip, and changes in top and bottom dimensions, width dimensions, and shoulder diameter changes due to changes in rolling temperature were added to the predicted deviation from the target value. A method for controlling the dimensions of a round bar according to claim 1.