CN100411759C - Method and device for adjusting the pressing position of rolls in a 3-high mandrel mill for seamless pipes - Google Patents

Abstract

The roll reduction position adjustment method and adjustment device of the present invention measure the wall thickness of the rolled material at the position corresponding to the bottom of each roll groove, and calculate the relationship between each wall thickness measured above and the target determined by the rolling schedule table. For variations in wall thickness, the reduction position of each roll is adjusted based on each variation calculated above, so that appropriate adjustment of the reduction position can be performed. In addition, the wall thickness of the material to be rolled is measured at a position corresponding to the portion from the groove bottom of each roll to the side of both flanges, and the pressing position of each roll is adjusted according to the deviation between the two measured values. The depressing position appears to be appropriate on the surface, but in fact the depressing position can also be properly adjusted. Therefore, it can be widely used as a reduction position adjustment mechanism of rolls constituting a 3-high mandrel mill.

Description

Method and device for adjusting the pressing position of rolls in a 3-high mandrel mill for seamless pipes

technical field

The present invention relates to a method and an adjustment device for adjusting the pressing position of rolls constituting the 3-high mandrel mill used for manufacturing seamless pipes.

Background technique

In the manufacture of seamless pipes using the Mannesmann mandrel mill method, first, after heating a round or square billet as a raw material to 1200-1260°C in a rotary hearth heating furnace, In the piercing machine, the mandrel and roll are used for piercing and rolling to produce a hollow tube blank. Then, the mandrel is inserted into the inner hole of the above-mentioned hollow shell to form a string, and the outer surface is restrained by grooved rolls in a mandrel-type seamless pipe rolling mill usually composed of 5 to 8 stands to carry out elongation rolling. system, thereby reducing the wall thickness to the specified wall thickness. Thereafter, the mandrel is drawn out, and the above-mentioned reduced-thickness pipe is formed and rolled into a predetermined outer diameter by a reducing mill to obtain a product.

In the past, mandrel mills mostly used 2-roller mandrel mills. In the 2-roller mandrel mills, each frame was equipped with a pair of opposite pass rolls. , and alternately arrange the rolling direction of the rolls by staggering 90° between adjacent stands. In addition, a 4-high mandrel mill in which four grooved rolls having an angle of 90° in the rolling direction are arranged on each stand is also used in some cases. In addition, a 3-high mandrel mill has also been proposed. In this 3-high mandrel mill, three holes with an included angle of 120° in the pressing direction are arranged on each stand. Type rolls are arranged alternately between adjacent stands, with the rolling directions of the rolls staggered by 60°.

Here, in order to ensure the wall thickness accuracy of the rolled material (pipe) in the mandrel mill and suppress its thickness deviation, the pressing position of each roll constituting the mandrel mill is properly controlled. Location is important.

Therefore, in the 2-roller type mandrel mill, such a method is often used to temporarily contact the flange portions of the opposing grooved rolls, and use the pressing position of each roll at this time as the zero point to control the pressing position. Lower position (for example, refer to Japanese Patent Application Laid-Open No. 9-174118). However, in a 3-high or 4-high mandrel mill, since the degree of freedom in the relative relationship between the pressing positions of each roll increases, the zero point cannot be adjusted correctly by this method, and furthermore, the pressing position of each roll cannot be adjusted. The lower position control is in the proper position.

In addition, in a 4-high mandrel mill, a method has been proposed in which the wall thickness of a material to be rolled is measured (radiation beam The sum of the wall thicknesses of the opposing portions of the passed rolled material) and adjust the rolling position of the rolls based on the measured value (for example, refer to Japanese Patent Application Laid-Open No. 8-71616).

FIG. 1 is a diagram illustrating a roll arrangement relationship in a three-high mandrel mill. As shown in Fig. 1, in a 3-high mandrel mill, the part of the material to be rolled that is opposite to the position corresponding to the bottom of each roll groove is the position corresponding to the flange of the other roll, usually, equivalent to The thickness of the material to be rolled at the position of the flange portion tends to fluctuate due to rolling conditions. Therefore, the relationship between the wall thickness and the roll reduction position is difficult to predict.

Therefore, even if the radiation wall thickness measuring device described in the above-mentioned Japanese Patent Application Laid-Open No. 8-71616 is used, the sum of the wall thicknesses of the opposing parts of the rolled material through which the radiation passes (that is, the wall thickness at the position corresponding to the bottom of each roll groove) is measured. The sum of the thickness and the wall thickness at the position corresponding to the flange portion of the other roll), it is also difficult to adjust the pressing position of the roll based on the measured value.

Contents of the invention

As described above, in the 3-high mandrel mill, unlike the 2-high and 4-high mandrel mills, by controlling the pressing position of each roll constituting the rolling mill to an appropriate position, An effective method to ensure the wall thickness accuracy of the rolled material and suppress the partial thickness has not yet been proposed.

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide an adjustment method and apparatus for appropriately adjusting the pressing position of the rolls constituting a three-high mandrel mill.

In order to achieve the above object, the inventor of the present invention thought through intensive research that instead of measuring the sum of the wall thickness at the position corresponding to the groove bottom of each roll and the wall thickness at the position corresponding to the flange portion of another roll as in the past, Instead, measure the wall thickness of the rolled material at the position corresponding to the bottom of each roll groove, which can predict the relationship with the roll reduction position, and adjust the reduction position of each roll according to the measured value. The wall thickness accuracy of the manufactured material is adjusted appropriately so that uneven thickness can be suppressed, and the present invention has been completed.

That is, the present invention provides a method for adjusting the roll-down position of a three-high mandrel mill, the method including the following three steps: the first step is to measure the position corresponding to the bottom of each roll groove; The wall thickness of the material to be rolled; the second step is to calculate the deviation between the above-mentioned measured wall thickness and the target wall thickness; the third step is to adjust the pressing position of each roll according to the above-mentioned calculated deviations.

According to this invention, the wall thickness of the rolled material at the position corresponding to the bottom of each roll groove is measured, and the deviation between the above-mentioned measured wall thickness and the target wall thickness determined by the rolling schedule table is calculated. Deviation, adjust the pressing position of each roll. The above-mentioned deviation is equivalent to the positional deviation from the zero point determined by the rolling program table as the position adjustment reference of each roll, so if the reduction position is adjusted according to the above-mentioned deviation (making the above-mentioned deviation to be 0), it can be adjusted for each roll. The rolls are properly adjusted in their depressed position.

In addition, when measuring the wall thickness of the rolled material at the position corresponding to the bottom of each roll groove, for example, the multi-ray beam described in "Iron and Steel" (Showa 70th No. 9, pages 1139 to 1145) can be used. In the radiation measuring method of the formula, it is only necessary to intersect each radiation beam at a position corresponding to the bottom of each roll groove (corresponding to the center of the wall thickness of the groove bottom) of the rolled material.

Here, in an actual mandrel mill, there are cases where the center position of the material to be rolled (the core of the material to be rolled) and each position where the wall thickness of the material to be rolled is measured (using the above-mentioned multi-ray beam In the case of type radiation, there is a deviation between the center of gravity positions where each radiation beam intersects.

Fig. 2 is a graph for apparent thickness deviation that occurs when the center position of a material to be rolled is shifted. When such a positional shift occurs, even if the rolled material does not actually have uneven thickness, it may be measured as having uneven thickness apparently. In FIG. 2 , for the sake of clarity, the wall thickness of the entire circumference of the material to be rolled is shown, but actually only the wall thickness at the position corresponding to the bottom of each roll groove was measured. The measurement error of the wall thickness is related to the adjustment error of the pressing position of each roll.

Therefore, the above-mentioned method for adjusting the rolling position of the roll preferably includes: a step of measuring the center position of the material to be rolled; In the second step, after correcting the measured wall thicknesses based on the calculated deviations, the deviations between the corrected wall thicknesses and the target wall thicknesses are calculated.

According to this invention, the center position of the material to be rolled is measured, the deviation between the measured center position and the position of the center of gravity of each position where the thickness of the material to be rolled is measured is calculated, and the above-mentioned measured position is corrected based on the calculated deviation. After each wall thickness is adjusted, the pressing position is adjusted based on the corrected wall thicknesses, so that a more accurate adjustment method can be realized.

In addition, when the center position of the rolled material is to be measured, for example, the outer diameter of the rolled material is measured from directions approximately perpendicular to each other, based on the center position of the outer diameter measured in one direction and the center position of the outer diameter measured in the other direction ( The coordinates of the center position of the rolled material can be calculated from the center position of the outer diameter measured in a direction approximately perpendicular to the above-mentioned one direction. In addition, in order to correct each measured wall thickness based on the deviation between the measured center position and the position of the center of gravity of each position for measuring the wall thickness of the rolled material, it is only necessary to calculate the above-mentioned deviation and the wall thickness measurement error ( The correlation relationship between the apparent thickness deviation) may be corrected based on the correlation relationship.

Fig. 3 is a diagram showing an example of a roll zero point adjustment state in a three-high mandrel mill. As shown in FIG. 3, among the three rolls R1, R2, and R3, the position where the flanges of the rolls R1 and R2 contact each other and the position where the flanges of the rolls R1 and R3 contact each other are adjusted to zero. (When rolling the material to be rolled, the pressing position of each roll moves an equal distance based on the zero point position), sometimes the wall thickness of the material to be rolled at the position corresponding to the bottom of the groove of each roll is measured. are approximately the same value. Accordingly, the pressing position of each roll is considered to be appropriate.

However, even if the thickness of the rolled material at the position corresponding to the groove bottom of each roll is measured to be approximately the same value, in the case shown in FIG. The wall thickness of the rolled material at the position of the part is different from the wall thickness at the position corresponding to the bottom of the groove, and uneven thickness occurs in the rolled material.

In view of the above situation, the inventors of the present invention have earnestly studied the method of appropriately adjusting the pressing position of each roll. The wall thickness of the material to be rolled is adjusted based on the measured value, and the pressing position of each roll is adjusted. In this way, the accuracy of the wall thickness of the material to be rolled can be ensured, and appropriate adjustment can be made to suppress uneven thickness. Thus, the present invention has been completed.

That is, in order to solve the above-mentioned problems, the present invention provides a method for adjusting the rolling position of the rolls constituting a three-high mandrel mill, the method including the steps of: The step of measuring the wall thickness of the rolled material at the position corresponding to the position of the rolled material at the position of the other flange part, and calculating the wall thickness of the rolled material at the position corresponding to the position of the other flange part; Steps for the deviation of the wall thickness at the position of the side part and the measured wall thickness at the position corresponding to the position of the other flange part side; adjust the pressing position of each roll according to the deviation calculated above A step of.

According to this invention, the wall thickness of the rolled material at a position corresponding to a portion deviated to one flange side from the bottom of each roll groove is measured, and the thickness of the rolled material at a position corresponding to a portion deviated to the other flange side is measured. According to the deviation of the two measured values for the wall thickness of the product, adjust the pressing position of the roll. Therefore, the wall thickness of the material to be rolled at the position corresponding to the bottom of each roll groove is measured to be approximately the same value, and even if the reduction position of each roll appears to be appropriate on the surface, it is possible to adjust the reduction position. to the actual location.

In addition, the adjustment amount when adjusting the pressing position of each roll based on the deviation of the two measured values may be determined so that the deviation of the two measured values becomes zero based on the geometrical conditions of the measured position of the two measured values and the groove bottom position.

In addition, in order to solve the above-mentioned problems, the present invention also provides a rolling reduction position adjustment device for rolls constituting a 3-high mandrel mill, which includes: a wall thickness measuring device having a plurality of radiation sources and a device to be rolled through A plurality of detectors arranged opposite to the respective radiation sources are used to measure the wall thickness of the rolled material at a position corresponding to the bottom of each roll groove; a pressing position control device calculates the above measured The deviation of the wall thickness from the target wall thickness is based on the calculated deviations to control the reduction device of each roll.

The above-mentioned roll reduction position adjustment device preferably further includes a center position measuring device for measuring the center position of the rolled material by measuring the outer diameter of the rolled material from directions approximately perpendicular to each other; the above-mentioned reduction position control A device that calculates the deviation between the center position measured by the center position measuring device and the center of gravity position of the intersection point of the radiation beams emitted from the plurality of radiation sources constituting the wall thickness measuring device, and corrects the measurement based on the calculated deviation. After calculating the corrected wall thicknesses, the deviation between the corrected wall thicknesses and the target wall thicknesses is calculated.

In addition, in order to solve the above-mentioned problems, the present invention also provides a rolling reduction position adjustment device for rolls constituting a 3-high mandrel mill, which includes: a wall thickness measuring device having a plurality of radiation sources and a device to be rolled through A plurality of detectors arranged opposite to the respective radiation sources are used to measure the wall thickness of the rolled material at a position corresponding to a portion deviated from the bottom of each roll groove to a flange side, and to measure the thickness of the rolled material corresponding to The wall thickness of the rolled material at the position of the part deviated to the other flange part side; the reduction position control device, which calculates the wall thickness at the position corresponding to the position of the one flange part deviated from the above-mentioned measurement, The deviation of the wall thickness at the position corresponding to the portion deviated to the other flange portion side measured above, and the reduction device of each roll are controlled based on each deviation calculated above.

According to the present invention, the wall thickness of the rolled material at the position corresponding to the bottom of each roll groove is measured, and the deviation between the above-mentioned measured wall thickness and the target wall thickness determined by the rolling schedule is calculated. Deviation, adjust the pressing position of each roll. This deviation is equivalent to the deviation from the zero point position determined by the rolling program table as the adjustment reference of each roll position. Therefore, if the reduction position is adjusted according to the above-mentioned deviation (making the above-mentioned deviation to be 0), it can be adjusted for each roll. The roll ensures the wall thickness of the material to be rolled, and can perform an appropriate adjustment of the pressing position to suppress uneven thickness.

In addition, according to the present invention, the wall thickness of the rolled material at a position corresponding to a portion deviated to one flange side from the bottom of each roll groove is measured, and the wall thickness of a rolled material corresponding to a position deviated to the other flange side is measured. According to the deviation of the two measured values, adjust the pressing position of each roll.

Therefore, since the wall thickness of the rolled material at the position corresponding to the groove bottom of each roll is measured to be approximately the same value, even if the reduction position of each roll appears to be appropriate, the reduction position can be adjusted. to the actual proper position.

Description of drawings

FIG. 1 is a diagram illustrating a roll arrangement relationship in a three-high mandrel mill.

Fig. 2 is a diagram explaining apparent uneven thickness that occurs when the center position of the material to be rolled is shifted.

Fig. 3 is a diagram showing an example of a roll zero point adjustment state in a three-high mandrel mill.

4 is a schematic configuration diagram showing a roll reduction position adjustment device constituting a three-high mandrel mill according to the first embodiment of the present invention.

Fig. 5 is a diagram showing a schematic structure of a wall thickness measuring device according to an embodiment of the present invention.

Fig. 6 is a diagram illustrating measurement locations of the wall thickness measurement device according to the embodiment of the present invention.

Fig. 7 is a diagram illustrating a roll arrangement relationship in a three-high mandrel mill.

Fig. 8 is a graph showing the relationship between the amount of eccentricity of the material to be rolled and the apparent uneven thickness.

Fig. 9 is a diagram illustrating a measurement site of a wall thickness measurement device according to another embodiment of the present invention.

Fig. 10 is a schematic configuration diagram showing a roll reduction position adjustment device constituting a three-high mandrel mill according to a second embodiment of the present invention.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1. First Embodiment

4 is a schematic configuration diagram of a roll reduction position adjustment device constituting a three-high mandrel mill according to the first embodiment of the present invention. As shown in FIG. 4, the reduction position adjustment device 100 of the present embodiment is a reduction position adjustment device for rolls constituting a three-high mandrel mill consisting of 6 rolls. Each stand is configured so that three rolls are arranged on each stand in order to stretch-roll the outer surface of the material to be rolled T in a state in which mandrels B are inserted into the inner hole in a string shape.

More specifically, the reduction position adjusting device 100 of the present embodiment adjusts the rolling position of the rolls R5 and R6 arranged on the last two stands (the fifth stand and the sixth stand) of the mandrel mill. to adjust the pressed position.

In addition, in Fig. 4, for the sake of clarity, it is shown that two rolls R5 and R6 are respectively arranged on each rack, but in fact, three rolls whose pressing directions are 120° to each other are respectively arranged. R5, R6.

The pressing position adjustment device 100 includes a wall thickness measuring device 1 and a pressing position control device 2 . The wall thickness measuring device 1 is arranged on the delivery side of the mandrel mill, and measures the wall thickness of the rolled material T at a position corresponding to the groove bottom of each roll R5, R6 (hereinafter referred to as groove bottom thickness). The reduction position control device 2 calculates the deviation between the wall thickness of each groove bottom measured by the wall thickness measuring device 1 and the target wall thickness corresponding to the position of the groove bottom determined by the rolling schedule, and controls each groove according to the deviation calculated above. Roller R5, R6 pressing device P5, P6.

In addition, in FIG. 4, for the sake of clarity, it is shown that one pressing device P5, P6 is respectively arranged on each stand, but in fact, each roll R5, P6 arranged on each stand R6 is equipped with a pressing device.

In addition, it is preferable that the pressing position adjusting device 100 of this embodiment further includes the center position measuring device 3 . The center position measuring device 3 measures the center position of the rolled material T by measuring the outer diameter of the rolled material T from directions substantially perpendicular to each other.

Fig. 5 is a schematic configuration diagram of a wall thickness measuring device according to an embodiment of the present invention. As shown in FIG. 5 , the wall thickness measuring device 1 is a so-called multi-beam type radiation measuring device, and has a plurality of radiation sources 11, 12, 13 and each radiation source 11, 12, 13 is connected to each other via a rolled material T. A plurality of detectors 14, 15, 16 arranged oppositely. The radiation beams BE1 , BE2 , BE3 radiated from the radiation sources 11 , 12 , 13 intersect at a position corresponding to the bottom of each roll groove (corresponding to the middle of the groove bottom) of the material to be rolled.

More specifically, since the groove bottoms of the rolls R5 and R6 in the fifth and sixth stands are at different positions (shifted by 60°), the wall thickness measuring device 1 is configured as shown in FIG. The devices with different crossing points of the radiation beams (staggered by 60°) are arranged in two stages along the axial direction of the rolled material T. On one stage, the groove bottom wall thickness of the roll R5 is measured, and on the other stage, the thickness of the roll R6 is measured. The bottom wall thickness of the tank.

Fig. 6 is a diagram illustrating measurement locations of the wall thickness measurement device according to the embodiment of the present invention. As shown in FIG. 6 , in one stage, the groove bottom wall thicknesses B1 to B3 in the fifth frame are measured, and in the other stage, the groove bottom wall thicknesses B4 to B6 in the sixth frame are measured. The entire wall thickness measuring device 1 is configured to measure all the groove bottom wall thicknesses B1 to B6. In addition, the specific method of measuring the wall thickness using the multi-beam type radiation measuring device in this embodiment is known, and the detailed description thereof will be omitted.

As shown in FIG. 4 above, the pressing position adjustment device 2 calculates the wall thicknesses B1 to B6 of the groove bottom measured by the wall thickness measuring device 1 and the target wall thickness at the position corresponding to the groove bottom determined by the rolling schedule table. The deviation of the thickness can be controlled by the reduction devices P5 and P6 of the respective rolls R5 and R6 based on the deviation calculated above.

More specifically, if the measured wall thickness of the groove bottom is smaller than the target wall thickness, the pressing device is controlled to move the corresponding roll in the opening direction (direction away from the center of the material T to be rolled). Conversely, if the measured wall thickness of the groove bottom is greater than the target wall thickness, the pressing device is controlled to move the corresponding roll in the closing direction (the direction approaching the center of the rolled material T). In addition, since the position must be corrected so that the above-mentioned deviation becomes zero, the movement amount (position correction amount) of each roll R5, R6 is set to the same degree as the above-mentioned deviation.

However, the reduction position control device 2 of this embodiment, as described above, may adopt a structure that includes a center position measuring device 3, and can correct the measured position based on the center position of the rolled material T measured by the center position measuring device 3. The wall thickness of the groove bottom is B1~B6.

7 is a diagram showing a schematic structure of a center position measuring device according to an embodiment of the present invention. As shown in FIG. 7 , the center position measuring device 3 of this embodiment has a rod-shaped light source (for example, a high-frequency lighting type fluorescent lamp) 31 that illuminates the material T to be rolled from one direction. A line sensor (for example, a CCD line sensor) 32 disposed opposite to the rod-shaped light source 31, a rod-shaped light source 33 that illuminates the rolled material T from a direction substantially perpendicular to the illumination direction of the rod-shaped light source 31, and the rolled material T are separated by the rod-shaped light source 31. The line sensor 34 facing the rod-shaped light source 33 is arrange|positioned in the material T. Using these, the outer diameter of the material to be rolled T (the length of the shadow of the material to be rolled T) is measured from directions substantially perpendicular to each other.

The coordinates of the center position of the rolled material T are calculated from the center position X of the outer diameter and the center position Y of the outer diameter. The center position X of the outer diameter is measured by a combination of the rod-shaped light source 31 and the line sensor 32. The center position Y of the diameter is measured by a combination of the rod light source 33 and the line sensor 34 .

As mentioned above, when the structure of correcting the measured groove bottom wall thicknesses B1 to B6 is adopted based on the center position of the rolled material T measured by the center position measuring device 3, the pressing position control device 2 first calculates the center position from the center position. The deviation between the central position (X, Y) measured by the measuring device 3 and the center of gravity position of the intersection point of the radiation beams emitted from the plurality of radiation sources 11 , 12 , 13 constituting the wall thickness measuring device 1 .

Fig. 8 is a diagram showing an example of the relationship between the amount of eccentricity and the apparent amount of thickness deviation of a material to be rolled. Here, the correlation between the above deviation and the measurement error (apparent deviation in thickness) of the measured groove bottom wall thicknesses B1 to B6 is calculated in advance through experiments, and is, for example, the relationship shown in FIG. 8 . Here, the horizontal axis of FIG. 8 represents the ratio of the above deviation (eccentricity of the rolled material) to the radius of the rolled material, and the vertical axis represents the apparent eccentric thickness component expressed by the following formula (1) .

Formula 1)

Apparently eccentric and thick components $\mathrm{Ecc}=\frac{4\&times;{({\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="C20048002939900221.png"\; state="\{\{state\}\}">R</figure-callout>}}^2+I^2)}^{1/2}}{\mathrm{W\; Tave}}\&times;100[\%]...\left(1\right)$

In the formula

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}}\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; \{</span>\frac{\mathrm{<span\; class="notranslate">\; wxya</span>}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; wxya</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span>$

$\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}}\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; \{</span>\frac{\mathrm{<span\; class="notranslate">\; wxya</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; wxya</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \}</span>$

WTn+1=WT1

θn+1=θ1+2π

n: number of measurement points

WTk: measured wall thickness of the kth measuring point [mm]

θk: The measurement position of the kth measurement point (the angle of the polar coordinates with the center of the rolled material as the origin) [rad]

In addition, the above-mentioned formula (1) is a general formula when the number of measuring points of the wall thickness is n. In the present embodiment, since the number of measurement points of each stage constituting the wall thickness measuring device 1 is three, n=3.

Next, the pressing position control device 2 corrects the measured groove bottom thicknesses B1 to B6 by the following equation (2) based on the above-calculated deviation (apparent eccentric thickness component).

Formula (2)

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; wxya</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; wxya</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="100"\; label="Ecc"\; filenames="C20048002939900221.png"\; state="\{\{state\}\}">Ecc</figure-callout></span>}}{\mathrm{<span\; class="notranslate">\; 100</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; arg</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; II</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In the formula

WTk: measured wall thickness of the kth measuring point after correction [mm]

i: imaginary unit

arg(): function to find the phase angle of a complex number [rad]

WTk, Ecc, θk, R, 1: same definition as formula (1)

In addition, the pressing position control device 2 calculates the deviation between the wall thickness of each groove bottom corrected by the above-mentioned formula (2) and the target wall thickness, and can control the pressing device P5 of each roll R5 and R6 based on the calculated deviations. , P6.

As described above, the reduction position control device 2 in this embodiment may have a structure in which the measured groove bottom wall thicknesses B1 to B6 are corrected based on the center position of the rolled material T measured by the center position measuring device 3 . , by adopting this structure, the pressing position can be adjusted with higher precision.

In addition, in this embodiment, the case where the wall thickness measuring device 1 measures only the groove bottom wall thicknesses B1 to B6 is described, but the present invention is not limited thereto, and the wall thickness measuring device 1 may also have other multiple radiation sources and A plurality of other detectors arranged opposite to each of these radiation sources through the rolled material T measure the rolled material at a position corresponding to a portion deviated from the groove bottom of each roll R5, R6 to one flange side. The wall thickness of T, and the wall thickness of the rolled material T at a position corresponding to a portion deviated to the other flange side was measured.

Fig. 9 is a diagram illustrating a measurement site of a wall thickness measurement device according to another embodiment of the present invention. As shown in FIG. 9, for the fifth stand, the wall thickness B11, B12: For the bottom of the groove where the groove bottom wall thickness B2 is measured, the wall thicknesses B21 and B22 of the rolled material T at the positions corresponding to the parts deviated to the sides of the flanges are also measured; for the groove bottom wall thickness B3 measured The wall thicknesses B31 and B32 of the rolled material T at the positions corresponding to the portions deviated to the side of both flanges were also measured at the bottom of the groove.

Next, for the sixth stand, the wall thicknesses B41 and B42 of the rolled material T at the position corresponding to the portion deviated to the sides of the flanges are also measured for the groove bottom where the groove bottom wall thickness B4 is measured; For the bottom of the groove whose wall thickness B5 is measured, the wall thicknesses B51 and B52 of the rolled material T at the positions corresponding to the parts deviated from the two flanges are also measured; for the bottom of the groove whose wall thickness B6 is measured, The wall thicknesses B61 and B62 of the to-be-rolled material T at positions corresponding to portions deviated toward both flange portions were also measured.

When the wall thickness measuring device 1 adopts the above-mentioned structure, the position control device 2 is pressed down, and the wall thickness (for example, wall thickness B11) at the position corresponding to the part biased to the one flange side measured above is calculated, and the above-mentioned measured wall thickness corresponding to the flange side is calculated. The deviation of the wall thickness (for example, the wall thickness B12) at the position of the part biased to the other flange side is based on the calculated deviations, and then controls the rolling devices P5, R5, and R6 of each roll R5 (R51, R52, R53). P6.

More specifically, for example, if the wall thickness B12 is larger than the wall thickness B11 corresponding to the roll R51, the pressing device P5 is controlled so that the roll R52 adjacent to the measurement position on the side with the larger wall thickness (wall thickness B12) faces Move in the opening direction (direction away from the center of the rolled material T), on the other hand, control the pressing device P so that the remaining two rolls R51 and R53 move in the closing direction (closer to the center of the rolled material T) .

Similarly, the deviations of B21 and B22, B31 and B32, B41 and B42, B51 and B52, B61 and B62 are respectively calculated, and the pressing device corresponding to the roll is similarly controlled according to its positive or negative (size).

In addition, since the position must be corrected so that the above-mentioned deviation becomes zero, for example, the straight line connecting the wall thickness measurement position deviated from the bottom of the groove to the flange side and the center of the roll pass is compared with the straight line connecting the bottom of the groove and the center of the roll pass. When forming an angle of 20 degrees, the movement amount (position correction amount) of each of the above-mentioned rolls R5 and R6 is expressed by the following formula (3).

Roll position correction amount (absolute value)

= Wall thickness deviation on both sides × 1/sin(20°) ...(3)

By employing the above structure, the groove bottom wall thicknesses B1 to B3, B4 to B6 of the respective rolls R5, R6 are measured to be approximately the same value, and even if the pressing positions of the respective rolls R5, R6 appear to be appropriate, it is possible to The pressed position is readjusted to the actually correct position.

2. Second Embodiment

Fig. 10 is a schematic configuration diagram showing a roll reduction position adjustment device constituting a three-high mandrel mill according to a second embodiment of the present invention. As shown in FIG. 10, the roll reduction position adjustment device 100A constituting the 3-high mandrel mill of the present embodiment also constitutes the 3-high mandrel mill as in the first embodiment. The roll reduction position adjustment device of the 3-roller type mandrel mill is composed of 6 stands, and is stretched and rolled in the state where the mandrel B is inserted into the inner hole in a string shape. The outer surface of the material T is rolled, and three rolls are arranged on each stand.

More specifically, the pressing position adjusting device 100A of the present embodiment also adjusts the rolls R5, R5, Depressed position of R6.

In addition, in FIG. 10 , for the sake of clarity, it is shown that two rolls R5 and R6 are respectively arranged on each frame, but in fact, three rolls R5 and R6 are respectively arranged with the pressing directions at 120° to each other. A roll R5, R6.

The reduction position adjustment device 100A, similar to the first embodiment, has a wall thickness measurement device 1A and a reduction position control device 2A. The wall thickness measurement device 1A is arranged on the delivery side of the mandrel mill, and the reduction position is The control device 2A controls the reduction devices P5 and P6 of the respective rolls R5 and R6 based on the measurement results of the wall thickness measurement device 1A.

In addition, in FIG. 10, for the sake of clarity, it is shown that one depressing device P5, P6 is respectively arranged on each frame, but in fact, each Both rolls R5 and R6 are equipped with a pressing device.

However, unlike the first embodiment, the wall thickness measuring device 1A of this embodiment does not measure the groove bottom wall thickness of the rolled material T, but has a plurality of radiation sources and separate A plurality of detectors arranged opposite to these radiation sources measure the wall thickness of the rolled material T at a position corresponding to a portion deviated from the groove bottom of each roll R5, R6 to a flange portion side, and measure the thickness corresponding to The wall thickness of the to-be-rolled material T at the position of the part deviated to the other flange part side.

Referring to Fig. 9 used in the description of the first embodiment, the wall thicknesses B1, B2, B3, B4, B5, and B6 at the bottom of the grooves are not measured, but are measured from the bottom of the grooves of each roll to the sides of the flanges. The wall thickness B11, B12, B21, B22, B31, B32, B41, B42, B51, B52, B61, B62 of the rolled material T at the position of the part.

In addition, the pressing position control device 2A of the present embodiment calculates the wall thickness (for example, the wall thickness B11 shown in FIG. The deviation of the wall thickness (for example, the wall thickness B12 shown in FIG. 9 ) at the position corresponding to the part biased to the other flange side, according to the above-mentioned calculated deviation, control each roll R5 (R51, R52, R53), R6 depressing device P5, P6.

More specifically, for example, if the wall thickness B12 is greater than the wall thickness B11 corresponding to the roll R51, the pressing device P5 is controlled so that the roll R52 adjacent to the measurement position on the side with the larger wall thickness (wall thickness 12) faces Move in the opening direction (direction away from the center of the rolled material T), on the other hand, control the pressing device P so that the remaining two rolls R51 and R53 move in the closing direction (closer to the center of the rolled material T) .

Similarly, the deviations of B21 and B22, B31 and B32, B41 and B42, B51 and B52, B61 and B62 are respectively calculated, and the pressing device corresponding to the roll is similarly controlled according to its positive or negative (size). In addition, since the position must be corrected so that the above-mentioned deviation becomes 0, for example, the straight line connecting the wall thickness measurement position deviated from the bottom of the groove to the flange side and the center of the roll pass is aligned with the straight line connecting the bottom of the groove and the center of the roll pass. When the angle is 20 degrees, the movement amount (position correction amount) of each of the above-mentioned rolls R5 and R6 is expressed by the following formula (3).

Roll position correction amount (absolute value)

= Wall thickness deviation on both sides × 1/sin(20°) ...(3)

By adopting the above structure, the groove bottom wall thicknesses B1 to B3, B4 to B6 of the rolls R5 and R6 are measured to be approximately the same value (in this embodiment, because the groove bottom wall thicknesses B1 to B3, B4 to B6, so if they are measured, they are measured to be approximately the same value), even if the reduction positions of the rolls R5 and R6 appear appropriate on the surface, the reduction positions can be readjusted to actually appropriate positions.

Example

Hereinafter, the characteristics of the present invention will be clarified by showing examples. Using the to-be-rolled material and the mandrel bar having the dimensions shown in Table 1, a production test of rolling 30 seamless steel pipes was carried out under the following conditions.

[Table 1]

Mandrel seamless tube mill tube billet size  Outer diameter 205mm×wall thickness 15mm Mandrel type seamless pipe mill completed size  Outer diameter 168mm×wall thickness 5mm mandrel diameter 158mm outer diameter

In addition, the test was carried out under four kinds of conditions, respectively. (1) Conventional method (a method in which the flange portions of the rolls are temporarily brought into contact with each other, and the pressing position of each roll at this time is taken as a zero point to control the pressing position); (2) Example 1 (measured value based on the groove bottom wall thickness) (3) Embodiment 2 (correct the measured value of the above-mentioned groove bottom wall thickness with the offset of the center position of the rolled material, and adjust the method of pressing position according to the correction value); (4 ) embodiment 3 (after the adjustment of embodiment 2, according to the deviation of the measured value of the flange portion side wall thickness of the roll, the method of adjusting the pressing position again); (5) embodiment 4 (according to the flange portion side of the roll The deviation of the measured value of the wall thickness, the method of adjusting the pressing position).

Table 2 shows the test results. As shown in Table 2, compared with the conventional method, the average value of the thickness deviation rate of Examples 1-4 and the frequency with which the thickness deviation rate exceeded 5% were reduced. This is considered to greatly contribute to the proper adjustment of the pressing position of the rolls constituting the 3-high mandrel mill according to the present invention.

[Table 2]

Method of manufacturing test The average value of thickness deviation Frequency of thickness deviation exceeding 5% Past method 6% 50% Example 1 (Adjustment of pressing position according to measured value of groove bottom wall thickness) 3% 30% Example 2 (Example 1+Correction with the offset of the center position of the rolled material) 1% 7% Example 3 (Example 2 + adjusting the pressing position according to the measured value of the side wall thickness of the flange portion of the roll) 0.1% 0% Example 4 (Adjust the pressing position according to the measured value of the flange side wall thickness) 3.5% 30%

Possibility of industrial use

According to the present invention, since the wall thickness of the rolled material at the position corresponding to the bottom of each roll groove is measured, the deviation between the above-mentioned measured wall thickness and the target wall thickness determined by the rolling schedule table is calculated, and the above-calculated Each deviation, adjust the pressing position of each roll. Therefore, it is possible to ensure the accuracy of the wall thickness of the material to be rolled for each of the rolls, and to perform appropriate adjustment of the rolling position to suppress uneven thickness.

In addition, according to the present invention, since the wall thickness of the rolled material is measured at a position corresponding to a portion deviated from the bottom of each roll groove to one flange portion side, and at a position corresponding to a portion deviated to the other flange portion side, the thickness of the rolled material is measured. According to the wall thickness of the rolled material, adjust the pressing position of each roll according to the deviation of the two measured values. Therefore, even when the pressing position of each roll appears to be appropriate apparently, the pressing position can be adjusted to an actually appropriate position. Accordingly, it can be widely used as a reduction position adjustment mechanism for rolls constituting a three-high mandrel mill.

Claims (6)

1. a depressing position method of adjustment that constitutes the roll of 3 tube by three-roll mandrel mill is characterized in that, comprising:

The 1st step, mensuration are equivalent to the wall thickness that is rolled material of the position of each knurling bottom;

The 2nd step is calculated each wall thickness that said determination goes out and the deviation of target wall thickness;

The 3rd step according to above-mentioned each deviation of calculating, is adjusted the depressing position of each roll.

2. the depressing position method of adjustment of the roll of formation 3 tube by three-roll mandrel mill according to claim 1 is characterized in that,

Comprise: the step of measuring the center that is rolled material;

Calculate the step of the deviation of the position of centre of gravity of measuring each position that is rolled the material wall thickness in center that said determination goes out and above-mentioned the 1st step;

In above-mentioned the 2nd step, according to the above-mentioned drift correction of calculating behind each wall thickness of going out of said determination, calculate the deviation of this revised each wall thickness and target wall thickness.

3. a depressing position method of adjustment that constitutes the roll of 3 tube by three-roll mandrel mill is characterized in that, also comprises:

Mensuration is equivalent to being rolled the material wall thickness, and measuring the step that is rolled the material wall thickness of the position of the part that is equivalent to be partial to another flange part side from the position of the part of each knurling bottom deflection one flange part side;

Being equivalent to of calculating that said determination goes out is partial to that the wall thickness of position of part of a flange part side and said determination go out is equivalent to be partial to the step of deviation of wall thickness of position of the part of another flange part side;

Adjust the step of the depressing position of each roll according to above-mentioned each deviation of calculating.

4. a depressing position adjusting device that constitutes the roll of 3 tube by three-roll mandrel mill is characterized in that, comprising:

The wall thickness determinator, its have a plurality of radiation sources with across being rolled relative with this each radiation source respectively a plurality of detectors that disposing of material, be used to measure the wall thickness that is rolled material of the position that is equivalent to each knurling bottom;

The depressing position control device, it calculates each wall thickness that said determination goes out and the deviation of target wall thickness, according to this each deviation of calculating, controls the screwdown gear of each roll.

5. the depressing position adjusting device of the roll of formation 3 tube by three-roll mandrel mill according to claim 4 is characterized in that,

Also comprise the center determinator, it measures the center that is rolled material by be rolled the external diameter of material from the mutual roughly direction detection of quadrature;

Above-mentioned depressing position control device, calculate the center that determines by above-mentioned center determinator, with the deviation of the position of centre of gravity in the crosspoint of the radiation beams that penetrates from a plurality of radiation sources that constitute above-mentioned wall thickness determinator, according to the above-mentioned drift correction of calculating behind each wall thickness of going out of said determination, calculate the deviation of this revised each wall thickness and target wall thickness.

6. a depressing position adjusting device that constitutes the roll of 3 tube by three-roll mandrel mill is characterized in that, comprising:

The wall thickness determinator, its have a plurality of radiation sources with across being rolled relative with this each radiation source respectively a plurality of detectors that disposing of material, be used to measure the wall thickness that is rolled material that is equivalent to from the position of the part of each knurling bottom deflection one flange part side, and measure the wall thickness that is rolled material of the position of the part that is equivalent to be partial to another flange part side;

The depressing position control device, it calculates that said determination goes out be equivalent to be partial to the position of a flange part sidepiece branch wall thickness, be partial to the deviation of wall thickness of position of the part of another flange part side with said determination being equivalent to of going out, according to the screwdown gear of above-mentioned each each roll of Deviation Control of calculating.

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