JPS63268507A - Control method for outer diameter of metal pipe - Google Patents

Abstract

PURPOSE:To improve the accuracy of an outer diameter of pipe by comparing the measured outer diameter on the inlet side of a sizing stand with targeted values of transversal and longitudinal outer diameters, then calculating transversal and longitudinal roll gap values of each sizing stand based on said comparison. CONSTITUTION:On each inlet side of the sizing stands 12A-12D disposed continuously, a measuring instrument 15 for the inlet side outer diameter is provided and a measuring instrument 18 for the outlet side outer diameter is disposed on the outlet side of the stand 12D, the measured values Dw and Dh on the top end of the blank pipe measured by the outer diameter measuring instrument 15 are compared with the target set outer diameter D of a outer diameter setting device 22. After that, the gaps of the transversal and longitudinal roll pairs are calculated to make the gaps of the transversal and longitudinal rolls pair of each stand 12A-12D into an equal contraction percentage by an arithmetic and control unit 21, then the outer diameter control of the blank pipe 11 is performed. In this way, because the outer diameter is feedback controlled ranging whole length of the blank pipe 11, the accuracy of the outer diameter is improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for controlling the outer diameter of a metal tube.

[Conventional technology] Conventionally, in a -IT stitched copper steel pipe production line, a plurality of sizing stands were arranged in succession in order to adjust the outer diameter of the tube formed into a tubular shape, and each sizing stand was equipped with a pair of horizontal rolls and a vertical roll. A pair of outer diameter control devices are used.

By the way, the outer diameter control 9 used in the forge welded steel pipe manufacturing line
As F11, as described in Japanese Patent Application Laid-Open No. 53-25259, a plurality of sizing stands are arranged in succession,
Each sizing stand is provided with a roll pair consisting of 20 rolls facing each other, and adjacent roll pairs are arranged around the pass line by 8 rolls.
The outer diameter of the sizing pipe is measured with an outer diameter measuring device installed on the exit side of the final sizing stand under the condition that the sizing stand is shifted by 0 degrees, and each stand is determined based on the above outer diameter measurement result and the target outer diameter. Feedback control of roll vs. gap has been proposed.

Therefore, the control technology according to the above-mentioned Japanese Patent Application Laid-Open No. 53-25259 has been applied to the above-mentioned outer diameter control device for manufacturing electric resistance welded steel pipes, etc., in which each sizing stand is constituted by 40 rolls of a pair of horizontal rolls and a pair of vertical rolls. It is possible to apply

[Problems to be Solved by the Invention] However, in the outer diameter control device described in Japanese Patent Application Laid-Open No. 53-252513, the measurement value of each sizing stand is determined based on the measured value on the exit side of the final sizing stand. Since the roll vs. gap is feedback controlled, the tip side of the raw tube, which has a length corresponding to the distance from the exit outside diameter measuring device to the furthest sizing stand, is not completely controlled, and the outside diameter This results in defects and lower yields.

An object of the present invention is to perform high-precision outer diameter control over substantially the entire length of a raw pipe and to improve yield.

[Means for Solving the Problems] The present invention provides an outer diameter of a metal pipe in which a plurality of sizing stands are arranged in succession and the outer diameter of the raw pipe is adjusted by a pair of horizontal rolls and a pair of vertical rolls provided on each sizing stand. In the control method, the outer diameter measuring device installed at the entrance of the first sizing stand measures the horizontal outer diameter and vertical outer diameter of the raw pipe, and the results of measuring the horizontal outer diameter of the outer diameter measuring device and the pipe after sizing are compared. From the target horizontal outer diameter, calculate the horizontal roll pair gap setting value of each sizing stand so that the horizontal roll pair gap has the same drawing ratio, and also calculate the vertical outer diameter measurement result of the outer diameter measuring device and sizing. Based on the target vertical outer diameter of the subsequent pipe, calculate the vertical roll vs. gap setting values of each sizing stand so that the vertical roll vs. gap has the same drawing ratio, and then calculate the horizontal roll vs. gap of each sizing stand. Each of the vertical rolls and gaps is controlled based on the above calculation results.

[Function] According to the present invention, the roll-to-gap of each sizing stand is feedforward controlled based on the measurement value measured at the entrance side of the first sizing stand, so that The outer diameter can be completely controlled over almost the entire length.

In addition, the results of measuring the horizontal outer diameter of the outer diameter measuring device are reflected in the control of the horizontal roll versus gap, and the results of measuring the longitudinal outer diameter are reflected in the control of the vertical roll versus gap.

There is good correspondence between the measured value and the gap setting value, and the gap control accuracy is good.

Also, since the roll-to-gap of each sizing stand is calculated so that the drawing ratio is the same between the stands,
There is no possibility that the aperture in some stands becomes excessive and causes cracks in the raw tube.

Therefore, the outer diameter can be controlled with high accuracy over substantially the entire length of the raw pipe, and the yield can be improved.

[Example] FIG. 1 is a schematic diagram showing an outer diameter control device to which the present invention is applied, FIG. 2 is a schematic diagram showing a sizing stand, and FIG. 3 is a schematic diagram showing an outer diameter measuring device.

The outer diameter control device 10 is installed on the lower wave side of a squeeze roll provided in an electric resistance welded steel pipe manufacturing line, and controls the outer diameter of a raw pipe 11 that is high-frequency resistance heat welded by the squeeze roll.

For example, the outer diameter control device 2tlO controls each of the first to fourth sizing stands 12A to 120 to i1! The outer diameter of the raw pipe 11 is adjusted by a pair of horizontal rolls 13 and a pair of vertical rolls 14 provided on each stand 12A-120 (see FIG. 2).

In the outer diameter control type 2110, the entry side outer diameter measuring device 15 is disposed on the entry side of the first stand 12A. The inlet outer diameter measuring device 15 measures the raw tube 1 by using an upper optical device 16A and a lower optical receiver 16B.
1, and the vertical inlet outer diameter Dhx of the blank tube 11 is measured using the right emitter 17A and the left receiver 17B (see FIG. 3).

Also, the outer diameter control device 21O is: 54 stands! An outlet outer diameter measuring device gl18 is placed on the outlet side of the 2D. The exit outer diameter measuring device M18 measures the exit side outer diameter Dwz of the blank tube 11 using the upper light transmitter 19A and the lower light receiver 19B, and
0A and the left receiver 20B, the output side vertical outer diameter Dh of the blank tube 11
Measure z.

Further, the outer diameter control device 10 includes an arithmetic and control device 21 .

Performance IX The i control device 21 uses the measurement results Dwx and Dhx of the tip of the raw pipe measured by the entry side outer diameter measuring device W15 and the target outer diameter D of the raw pipe set in the target outer diameter setting device 22 (this In the embodiment, the target horizontal outer diameter = target vertical outer diameter), (2) The horizontal roll pair gap setting value D wi of each stand 12A-120 is set so that the horizontal roll pair gap of each stand 12A-120 has the same drawing ratio. (Calculate i=1 to 0 based on the following formula (1), and set the vertical roll-to-gap setting value D hi so that the vertical roll-to-gap of each stand 12A-12D has the same drawing ratio. (+-1～
4) is calculated based on the following equation (2).

Dwi=Dwx+(D-Dvx)X(i/n)-(
1) Dhi=Dhx+CD-Dhx)X(f/n)
・”(2) In addition, the calculation amount W device 21 is connected to each stand 12.
Measured value Gwi of lateral roll vs. gap at A~120
(i・1~4) and the measured value of the vertical roll versus gap G h
i (iml~4) is transmitted, (each stand 12A
~120 lateral roll vs. gap control 10ui (i・1~
0 is calculated based on the following formula (3).

(→ Vertical roll vs. gap control mFIMOhi of each stand 12A-120 (i-1 to 0 are calculated based on the following equation (4).

Owi=Dvi−Gwi
-(3) Ohi-D hi -G hi
(4) The arithmetic and control device 21 outputs Owi, which is the above calculation result, as a start signal to the lowering control motor of the horizontal roll pair of each stand 12A to 120, and
i is output as a starting signal to the vertical roll pair rolling down control motor.

Here, the above calculation amount u4 equipment Fi21 is calculated for each stand 12A.
The timing for controlling the rolling down control motors for the pair of horizontal rolls and the pair of vertical rolls in -12D is carried out immediately after the tip of the raw tube 11 is bitten into the stand, and as a result, the lowering control motors for the pair of horizontal rolls and the pair of vertical rolls are controlled. It is desirable to control the caps of each pair of rolls while eliminating the influence of the amount of elastic deflection (springback amount) when the pipe is bitten.

In this embodiment, the rfNrL control device 21 uses the measurement results D wz, D h of the outlet outer diameter measuring device 18.
z is also obtained, the deviation amount between these Dvx and Dhz and the target outer diameter is calculated, and the fourth
The horizontal roll pair gap and the vertical roll pair gap of the stand 120 are feedback-controlled.

Hereinafter, specific implementation results using the control system shown in FIG. 1 will be described. This specific example has an outer diameter of 20
The above example is applied to an electric resistance welded steel pipe with a wall thickness of 12.7t (STK41).The results are as shown in Table 1. According to Table 1, by implementing the present invention, the final Good results were obtained for both the horizontal outer diameter Dwz and vertical outer diameter Dhz of the finished tube measured at the exit side of the fourth stand 120 of ±0.1 mm with respect to the target outer diameter.
The finished tube had no cracks and had good surface quality.

As described above, according to the above embodiment, the roll-to-gap of each sizing stand 12A to 12D is feedforward controlled by the outer diameter measurement value measured at the entrance side of the first sizing stand 12A. Base pipe 1
It is possible to completely control the outer diameter over substantially the entire length from the leading end to the trailing end.

In addition, since the horizontal outer diameter measurement result of the outer diameter measuring device 15 is reflected in the horizontal roll versus gap control, and the vertical outer diameter measurement result is reflected in the vertical roll versus gap control, the measured value and the gap setting value are The gap control accuracy is good.

In addition, since the roll-to-gap of each sizing stand 12A to 12D is calculated so that the drawing ratio is the same between the stands, there is no possibility that the drawing ratio of some stands may become excessive and cause cracks in the raw pipe 11. Never.

Therefore, the outer diameter can be controlled with high accuracy over substantially the entire length of the raw tube 11, and the yield can be improved.

FIG. 4 is a schematic diagram showing another embodiment of the outer diameter control device. The embodiment shown in FIG. 4 differs from the embodiment shown in FIG. 1 in the following points.

That is, the outer diameter control device 10 controls the elastic deflection amount (springback amount) δW+, δhi (t=1 to 4 ) is determined in advance according to the outer diameter, plate thickness, and standard of the raw pipe 11, and is stored in the deflection position setting device 31 like a table. The data stored in the deflection position setter 31 is transferred to the arithmetic and control unit 21 and used as described below.

The ri4'a control device 21 converts the calculation results of the horizontal roll gap setting value Dw+ and the vertical roll gap setting value Dhi calculated using the equations (1) and (2) into the elastic deflections δIll and δhi, respectively. (5) below,
A preset horizontal roll gap value Fwi (i=1 to 4) and a preset vertical roll gap value Fhi (i=1 to 4) are calculated based on equation (8).

Fwi=Dwi−δwj...(5
)Fhi=Dhi−δhi...
(6) In addition, the arithmetic and control unit 21 is configured to control each stand 12A to
12D lateral roll-to-gap measurement Gwi;
The measured value Ghi of the vertical roll vs. gap is transmitted, and the horizontal roll vs. gap pre-control W@Pw of each stand 12A-12D is transmitted.
i (i=1 to 4) and vertical roll to gap pre-control amount Ph1
(i=1 to 4) is calculated based on the following equations (7) and (8).

P vi = F wi − G wi
−(7)P hi=F hi −G hi
...(8) tA calculation control device 21. Before starting to insert the raw pipe 1 into each stand 12A-12D, calculate Pwi, which is the above calculation result, to the stand 12A-12I).
Outputting Phi as a starting signal to the rolling down control motor of the pair of horizontal rolls, outputting Phi as a starting signal to the rolling down controlling motor of the pair of vertical rolls of the stands 12A to 120;
Preset each roll-to-gap.

Therefore, according to the control method shown in FIG. 4 above, the gap between each pair of rolls changes from before the end of the raw tube starts biting into the pair of rolls of each stand (during off-loading). This will be preset in consideration of the elastic flexure that will occur.

Therefore, the gap between each pair of rolls when the raw tube 11 is bitten (on-load) is set to an appropriate value over the entire length from the tip of the raw tube 11, and the yield can be improved by 2L.

Hereinafter, specific implementation results using the control system shown in FIG. 4 will be described. This specific example has an outer diameter of 20"
× Thick! The above embodiment is applied to a 2.7t (STK41) electric resistance welded steel pipe. The implementation results are as shown in Table 2. According to Table 2, by implementing the present invention, both the horizontal outside diameter Dwz and the vertical outside diameter t'1Dhz of the finished pipe measured at the exit side of the final fourth stand 12D Good results were obtained over the entire length, starting from the 100 layer layer at the tip of the tube. Furthermore, the finished tube had no cracks and had good surface quality.

[Effects of the Invention] As described above, according to the present invention, highly accurate outer diameter control can be performed over substantially the entire length of the raw pipe, and the yield can be improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an outer diameter control device to which the present invention is applied, Fig. 2 is a schematic diagram showing a sizing stand, and Fig. 3 is a schematic diagram showing a sizing stand.
The figure is a schematic diagram showing an outer diameter measuring device, and FIG. 4 is a schematic diagram showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Outer diameter control device, 11... Base pipe, 12A-120... Sizing stand, 13...
Horizontal roll pair, 14... Vertical roll pair, 15... Entry side outer diameter measuring device. 21... Arithmetic control device. 22...Target outer diameter setting device, 31...Deflection position setting device. Agent Patent Attorney Osamu Shiokawa Figure 2

Claims (2)

[Claims] (1) In a metal pipe outer diameter control method in which a plurality of sizing stands are arranged in succession and the outer diameter of the raw pipe is adjusted by a pair of horizontal rolls and a pair of vertical rolls provided on each sizing stand, the first sizing stand is The horizontal and vertical outside diameters of the raw pipe are measured using the outside diameter measuring device installed on the side, and the lateral outside diameter of each sizing stand is determined from the results of the outside diameter measurement of the outside diameter measuring device and the target horizontal outside diameter of the pipe after sizing. Calculate the horizontal roll pair gap setting values so that the horizontal roll pair gaps have the same drawing ratio, and from the vertical outer diameter measurement results of the outer diameter measuring device and the target vertical outer diameter of the pipe after sizing, Calculate the vertical roll-to-gap setting values so that the vertical roll-to-gap of each sizing stand has the same drawing ratio, and apply the above calculation results to the horizontal roll-to-gap and vertical roll-to-gap of each sizing stand. A method for controlling the outer diameter of a metal tube, characterized in that the outer diameter of the metal tube is controlled based on the following: (2) In claim 1, the amount of elastic deflection of each pair of horizontal rolls and vertical rolls of each sizing stand when the raw tube is bitten is determined in advance according to the outer diameter, plate thickness, and standard of the raw tube. Then, calculate a horizontal roll gap preset value and a vertical roll gap preset value by correcting the calculation results of the horizontal roll gap setting value and the vertical roll gap setting value by the elastic deflection amount, respectively, A method for controlling the outer diameter of a metal tube, in which each of the horizontal roll pair gap and the vertical roll pair gap of each sizing stand is preset based on the above preset values before starting biting of the raw tube.