JP2000051942A - Method for detecting joined part in continuous rolling, method for tracking joind part and devices therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detecte and track a joined part and to surely remove the joined part after rolling by generating artificial flaws in the joined part by removing burrs generated, leaving a part of the burrs before rolling and detecting the artificial flaws by a joined-part detecting means after finish rolling. SOLUTION: A flying joining device 2 is arranged between a heating furnace 1 and a roughing mill 4 and, furthermore, a deburring device 3 is arranged between the flying joining device 2 and the roughing mill 4. Two billets to be joined are glasped with a glasping device which doubles as an electrode and, after that, flash butt welding is executed. In the deburring device 3, the edge of a cutting tool is arranged so as to be parallel to a rolled stock and the burrs are removed by cutting the burrs with the edge by the movement of the rolling mill with rolling. In deburring, the burrs are removed leaving specified height. After removing the burrs leaving a part of the burrs, rolling is executed. Remaining burrs become overlapping flaws by rolling and the flaws are detected with the joined part detecting means 10 combined a rolled stock detector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a joint of a rolled material in continuous rolling of metal, particularly steel, a method for tracking a joint, and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, in hot rolling of a metal, for example, steel, a rolled material having a predetermined length is individually rolled on each strand. In this case, since the tension at the front and rear ends of the rolled material is not applied during rolling, the dimensions are deviated, and the leading and trailing ends have to be trimmed for each rolled material. In addition, the rolled material after finish rolling has a small cross-sectional area and a high rolling speed, so that the leading end of the rolled material without tension is unstable, and the rolled material is liable to cause misrolling due to tipping. At present, in the field of wire rods, the rolling speed has been increasing, and the progress speed after finish rolling has reached 100 m or more per second. Also,
In order to omit the step of secondary processing using a wire as a material, the diameter of the product after the wire rolling has been reduced, and the probability of occurrence of misroll has been increased due to the increase in speed and the reduction in diameter.

[0003] There is known a continuous rolling method in which the rear end of a preceding rolled material that has started rolling and the leading end of a succeeding rolled material extracted from a heating furnace are sequentially joined to perform endless rolling. If this continuous rolling method is employed, the trimming loss at the leading and trailing ends of the rolled material and the occurrence of misrolling at the leading end of the rolled material in the conventional discontinuous rolling are greatly reduced. In continuous rolling, a traveling joining device is arranged between the extraction end of the heating furnace and the rolling mill, and the traveling joining device travels with the preceding material that has started rolling, and is extracted from the rear end of the preceding material and the heating furnace. Join the tip of the row material.

[0004] As a joining method of the preceding material and the succeeding material, a butt welding method such as an upset welding method or a flash butt welding method capable of joining the end faces of the rolled material over the entire surface is used. To reduce the cross-sectional area and roll while greatly deforming steel bars and wire rods three-dimensionally with a roll with a caliber hole shape, it is necessary to firmly join so that the joints do not break during rolling, At the same time, it is necessary to minimize the yield loss due to joining, but the butt welding method can satisfy these conditions. Above all, in the flash butt welding method, since the bonding surface is melt-bonded by flash and then pressurized, the entire surface can be bonded without end face processing if a certain level of flatness is maintained. Therefore, the flash butt welding method is optimal as a method for joining a rod-shaped rolled material used as a rolled material of a bar or a wire. In flash butt welding, the leading material and the following material are each held by a holder also serving as an electrode, and then the trailing edge of the preceding material and the leading edge of the following material are brought into contact. Butt welding using arc heat generated after melting and scattering.

[0005] After continuous rolling, the joint of the rolled material may have a different tensile strength and structure than the base material, and such an unsteady portion of the rolled material needs to be removed after rolling.
For this purpose, it is essential to reliably track the joints of the rolled material after rolling and to detect the actual joints.

As a method of tracking a rolled material joint, at least two or more holes are formed in the vicinity of the rolled material joint in the longitudinal direction, and the position of the hole is tracked (Japanese Patent Publication No. 4-69004). Japanese Patent Application Laid-Open No. Hei 4-1992) and a method in which a width difference is provided between a rear end of a preceding rolled material and a front end of a succeeding rolled material and joined, and the width difference is tracked.
No. 89136) and a method of continuously measuring the temperature of a joined rolled material, and comparing the measured result with a previously grasped temperature deviation pattern of an unsteady portion to determine a joined material of a rolled material ( Japanese Patent Application Laid-Open No. Hei 7-265921) has been proposed.

[0007]

The conventional joint tracking method as described above can be implemented in the range of cold rolling or hot rolling in which a plate-like rolled material is rolled. When a rod-shaped rolled material is used, it is not easy to make a hole in the rolled material and the width difference cannot be changed. In addition, the temperature of the rolled material around the joint is also small when the rod is rolled with a large area reduction rate, and the temperature difference from the base metal becomes small due to the heat generated by the deformation resistance of the rolled material.

The present invention provides a joint detection method, a joint tracking method, and a device for reliably tracking joints even after continuous rolling using a rod-shaped rolled material. The purpose is to provide.

[0009]

That is, the gist of the present invention is as follows.

The first method is a method for detecting a joint portion after joining and rolling a preceding material and a succeeding material in continuous rolling. When removing burrs generated by joining before rolling, the burrs are removed. An artificial flaw is generated in a joint by removing a part thereof, and a joint is detected by detecting the artificial flaw by a joint detecting means after finish rolling. . When removing burrs, it is possible to remove splashing deposits from flash butt welding and remove burrs while leaving a raised portion of the rolled material at the joint. Also,
The tool for removing burrs can be characterized in that when receiving a reaction force from a rolled material, the distance from the center of the rolled material increases according to the magnitude of the reaction force.

When flash butt welding is used for joining rolling materials in continuous rolling, burrs are generated on the outer peripheral portion of the joining surface. If rolling is performed as it is without removing the burrs, the burrs become fold flaws and defects are generated at those portions. Furthermore, the splashed matter adhered to a part of the burr piece or the burr portion, particularly the splashed matter of flash butt welding, was peeled off from the rolled material during rolling when the rolling was performed with this adhered, and further peeled. The burrs or splashes bite into the base material other than the joint of the rolled material and cause new flaws.

In the present invention, since the joint is finally cut and removed, flaws generated at the joint by burrs do not become product defects. The feature of the present invention resides in that the joint is detected by detecting the flaw of the joint due to the burr after rolling. On the other hand, in order to prevent a part or burrs of the burr pieces from being peeled off from the rolled material during rolling and causing flaws other than at the joint, in the present invention, harmful burrs are removed and some burrs are left. To remove burrs. In particular, it is effective to remove the spatter attached to the flash butt welding.

[0013] The second is a method for detecting a joint after joining and rolling a preceding material and a succeeding material in continuous rolling, and the joining is performed to such an extent that the joint does not break during rolling. In the joint detection method characterized in that an artificial flaw is generated in the joint by performing joining that causes a defect, and the joint is detected by detecting the artificial flaw by the joint detecting means after finish rolling. is there. Here, the size of the defect at the joint can be adjusted by adjusting the pressing pressure between the preceding material and the following material during flash butt welding.

In joining rolled materials, joining can be performed without any defect on the joining surface, while joining can be performed while leaving some defects on the joining surface, that is, unjoined portions. If the number of unjoined portions in the joined surface is small, it is possible to detect a defect in the joined portion by the flaw detection means after rolling while preventing occurrence of a splitting trouble in the joined portion in rolling. The feature of the present invention resides in that the joint is detected by detecting the joint defect after rolling. In order to keep the size of the unjoined portion within an appropriate range, it is preferable to adjust the pressing pressure between the preceding material and the following material during flash butt welding.

Thirdly, the time T from when the rear end of the rolled material after the start of rolling passes the fixed point A before the rough rolling mill to when it passes the fixed point B after the end of rolling is previously confirmed by discontinuous rolling, It is characterized in that the time from when the rear end of the rolled material before the joining in the continuous rolling passes the fixed point A to when the joined portion at the rear end of the rolled material reaches the fixed point B is predicted using time T, This is a method for tracking a rolled material joint in continuous rolling.
In addition, the time T 'from when the leading end of the rolled material immediately before the start of rolling passes the fixed point C immediately before the rough rolling mill to when it passes through the fixed point B after the end of the rolling is previously checked, and after the rolled material before joining in the continuous rolling, The time from the end passing the fixed point A before the rough rolling mill until the joint at the rear end of the rolled material reaches the fixed point B is defined as time T ′, the distance L1 from the fixed point A to the fixed point C, and the rough rolling. This is a method for tracking a rolled material joint in continuous rolling, wherein the prediction is performed using the speed V1 of the immediately preceding rolled material. Here, the time from when the joint at the rear end of the rolled material passes through the fixed point B after the end of rolling to when it reaches the fixed point D after the end of rolling is defined as the distance L2 from the fixed point B to the fixed point D and the finish rolled material. By performing prediction using the transport speed V2, the rear end of the rolled material before joining in continuous rolling passes the fixed point A in front of the rough rolling mill, and then the joined portion of the rear end of the rolled material reaches the fixed point D. You can predict the time until.

In using the means for cutting and removing the joint by grasping the position of the joint after rolling, in addition to the method using the means for detecting the joint as in the first and second inventions,
It is possible to adopt a method of estimating and tracking the time when the joint arrives at a predetermined position after rolling.

When the rolling conditions such as the rolling speed and the rolling type are similar, the time required for a predetermined position of the rolled material to reach each point downstream of the rolling line from a fixed point in front of the rolling mill is: Is almost constant irrespective of the rolled material. Therefore, for the first rolled material of the same lot, if the time required to reach the fixed point B downstream of the rolling line from the fixed point A in front of the rolling mill is measured, after starting the rolling of the subsequent rolled material, Before joining the rear end of the succeeding rolled material with the further succeeding rolled material, the time at which the rear end of the subsequent rolled material passes the fixed point A is measured, and from that time, the time equal to the first rolled material is measured. After the passage, the joint at the rear end of the subsequent rolled material is fixed point B
Can be predicted.

In measuring the time required to reach the first rolled material, if the first rolled material is not continuous rolling but discontinuous rolling, the rear end of the first rolled material passes through the fixed point A. The above object can be achieved by measuring the time T from passing through to the fixed point B.

Also, a fixed point C is set immediately before the rough rolling mill,
The time T 'from the time when the leading end of the first rolled material passes through the fixed point C to the time when the leading end of the first rolled material passes through the fixed point B is measured, and the above-described predetermined calculation is performed. From this, it is possible to predict the time at which the joint at the rear end of the subsequent rolled material reaches the fixed point B. According to this method, the above object can be achieved even if the first rolled material is continuously rolled. Further, even when the fixed point D (joining portion cutting position) exists at a position different from the fixed point B (end detection position), the predetermined calculation is performed by using the finished rolled material conveying speed V2. Tracking can be performed.

Fourth, the time required for the joint to reach the position of the joint detecting means after finish rolling is predicted in advance by using the method for tracking a rolled material joint in continuous rolling according to the third invention, and the prediction is performed. Within the range of the predetermined time width before and after the time, the position where the flaw signal equal to or more than the predetermined threshold value is obtained by the joint detecting means of the joint detecting method of the first or second invention is determined. This is a method of tracking a rolled material joint in continuous rolling, characterized in that the tracking is corrected by determining that the rolling material is joined. Further, the time required for the joint to reach the position of the joint detection means after finish rolling is predicted in advance using the tracking results performed on the joint of the preceding rolled material, and a predetermined time width before and after the predicted time is calculated. In the range of the above, the position where the flaw signal equal to or more than the predetermined threshold value is obtained by the joint detecting means of the joint detecting method of the first or second invention is determined as the joint and the tracking is corrected. This is a method for tracking a rolled material joint in continuous rolling.

As in the first and second aspects of the present invention, the joint can be detected by detecting an artificial flaw attached to the joint. However, a flaw existing in a portion other than the joint is mistaken for the joint. There is a possibility to recognize. On the other hand, in the tracking method based on the rolling result of the preceding rolled material as in the third aspect, there is a possibility that a variation occurs in the predicted position based on the rolling variation for each rolled material. The fourth aspect of the present invention provides a method for more accurately tracking a joint by combining the first or second aspect of the present invention with the third aspect of the present invention.

Based on the third invention, the time at which the joint reaches the fixed point B after rolling is predicted. Before and after the predicted time, a range of a predetermined time width is set in consideration of the variation in the arrival time of each rolled material, and within the range of the time width, the joint detection of the first or second invention is performed. If a flaw signal equal to or greater than a predetermined threshold value is obtained by the joint detection means of the method, the first or second invention or the third invention is used alone by recognizing the flaw signal position as a joint. As a result, it is possible to obtain more accurate tracking information.

The third invention is a tracking method using discontinuous rolling or a first rolled material.
On the other hand, the actual rolling conditions may change every moment as the rolling progresses, and if continuous rolling is continued for a large number of rolled materials, the accuracy of using only the tracking information of the first rolling is not sufficient. May deteriorate. Therefore, in the fourth aspect of the invention, it is effective to perform tracking by using the tracking result performed on the joined portion of the preceding rolled material instead of the tracking result of the first rolling. By sequentially correcting the tracking information in this manner, tracking can be performed with high accuracy even when the rolling conditions change momentarily during continuous rolling.

Fifth, there is provided a joint detecting apparatus for detecting a joint after joining and rolling a preceding material and a succeeding material in continuous rolling. Deburring means for generating an artificial flaw in the joint by removing a part thereof, and a joint detecting means for detecting the artificial flaw arranged on the rear surface of the finish rolling and detecting the artificial flaw, It is a joint detecting device. The deburring means can remove only the spatter attached to the flash butt welding when removing the burrs, and can remove the burrs while leaving the raised portion of the rolled material at the joint. In addition, the cutting tool for removing burrs may be characterized in that, when receiving a reaction force from the rolled material, the distance from the center of the rolled material increases according to the magnitude of the reaction force. A joint detecting device for implementing the joint detecting method of the first invention.

A sixth aspect of the present invention is a joint detecting apparatus for detecting a joint after joining and rolling a preceding material and a succeeding material in continuous rolling, wherein the joining is performed so that the joint does not break during rolling. A joining means for performing joining to cause a defect in the joining portion to generate an artificial flaw in the joining portion, and disposed on a surface after finish rolling,
A joint detecting device comprising a joint detecting means for detecting a joint by detecting the artificial flaw. The joining means can adjust the size of the defect at the joint by adjusting the pressing pressure between the preceding material and the following material during flash butt welding. A joint detecting device for implementing the joint detecting method of the second invention.

Seventh, means for measuring the time at which the rear end of the rolled material after the start of rolling passes the fixed point A before the rough rolling mill, and the time at which the rear end of the rolled material passes the fixed point B after the end of rolling. And a time T from when the rear end of the rolled material passes the fixed point A to when it passes the fixed point B is previously confirmed by discontinuous rolling, and after the rolled material before joining in continuous rolling, A rolled material for continuous rolling, characterized by having a calculating means for predicting, using a time T, a time from an end passing through the fixed point A until the joint at the rear end of the rolled material reaches the fixed point B. It is a joint tracking device. Further, means for measuring the time at which the leading end of the rolled material immediately before the start of rolling passes the fixed point C immediately before the rough rolling mill, and measuring the time at which the trailing end of the rolled material after the start of rolling passes the fixed point A before the rough rolling mill. Means, and means for measuring the time when the leading end of the rolled material passes the fixed point B after the end of the rolling, and further, the fixed point after the end of the rolling after the leading end of the rolled material passes the fixed point C immediately before the rough rolling mill. The time T ′ before passing through B is checked in advance, and after the rear end of the rolled material before joining in continuous rolling passes the fixed point A before the rough rolling mill, the joined portion of the rear end of the rolled material reaches the fixed point B. Time to reach, time T ',
An apparatus for tracking a rolled material joint in continuous rolling, comprising a calculating means for predicting using a distance L1 from a fixed point A to a fixed point C and a speed V1 of the rolled material immediately before rough rolling. Further, the time from when the joint at the rear end of the rolled material passes through the fixed point B after the end of rolling to when it reaches the fixed point D after the end of rolling is defined as the distance L2 from the fixed point B to the fixed point D and the finished rolled material conveyance. A calculating means for predicting using the speed V2, the rear end of the rolled material before continuous rolling joining passes through a fixed point A in front of a rough rolling mill, and then the joined portion of the rolled material rear end reaches the fixed point D. The time to reach can be predicted. It is a rolled material joint tracking apparatus for performing the third method of tracking a rolled material joint.

Eighth, the present invention comprises the continuous material rolling section tracking device for continuous rolling according to the seventh aspect of the present invention and the joint detecting apparatus according to the fifth or sixth aspect of the present invention. The time at which the joint reaches the detection means position is predicted in advance using the rolling material joint tracking device for continuous rolling, and within a predetermined time width before and after the predicted time, the joint detection device In the continuous rolling rolling material joint tracking device, characterized in that it has a calculating means to judge the position where a flaw signal equal to or more than a predetermined threshold value is obtained in the joint detecting means as the joint and correct the tracking. is there. In addition, the present invention has the joint detecting device according to the fifth or sixth aspect of the present invention, and further has a tracking time for the joint to reach the position of the joint detecting means after finish rolling with respect to the joint of the preceding rolled material. Predicted in advance using the result, within a range of a predetermined time width before and after the predicted time, a position where a flaw signal equal to or more than a predetermined threshold value is obtained in the joint detecting means of the joint detecting device. An apparatus for tracking a rolled material joint in continuous rolling, comprising a calculation means for determining a joint and correcting tracking. It is a rolled material joint tracking apparatus for performing the fourth rolled material joint tracking method.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall view of a rolling equipment to which the present invention is applied, taking a strip steel wire rolling equipment as an example. The rolled material extracted from the heating furnace 1 is sequentially joined by the running joining device 2. The deburring device 3 is arranged between the running joining device 2 and the rough rolling mill 4. The joint detecting means 10 of the present invention is arranged at a stage subsequent to the finishing mill 6. The wire rod after the finish rolling is guided to the convergence device 8 through the winding device 24 and the adjusting and cooling equipment 7, and is bunched.

The fixed point A of the present invention is near the joining start position of the running joining apparatus 2 and the fixed point B is the joint detecting means 1 after finish rolling.
At a position near 0, the fixed point C is located immediately before the roughing mill 4 and at a fixed point D.
Is disposed in the vicinity of the winding device 24 or in the focusing device 8.

A method and an apparatus for detecting a joint according to the first and fifth aspects of the present invention will be described. In the continuous rolling of the present invention, a flash butt welding method is most commonly used as a method for joining rolled materials. In flash butt welding, when the butt end faces come into contact during joining, Joule heat due to the current flowing through the contact and melting of the contact
This is a butt welding method using arc heat generated after scattering. As a result of the butting, burrs 13 as shown in FIG. 2 are formed on the joining surface after the joining. In addition, the scattered flash adheres to the surface of the rolled material in the vicinity of the joint to form the scattered adhering matter 14.

Among the burrs 13, the tip of the burrs may peel off from the rolled material during rolling. If it is separated from the rolled material during rolling and adheres to the base material other than the joint, it will bite into the base material surface and become a surface defect. For this reason, it is necessary to remove the burr tip by a deburring device. On the other hand, the base of the burr does not peel off from the rolled material even by rolling. Then, the root portion is folded into the rolled material by rolling as shown in FIG. Such a fold flaw can be easily detected by a normal flaw detection means installed in the rolling equipment, for example, an eddy current flaw detector or an ultrasonic flaw detector. Therefore, by removing only the tip of the burr by the deburring device and not removing the base of the burr, it becomes possible to detect the joint after rolling without causing harmful flaws.

Further, if the scattered flash 14 adheres to the rolled material surface and is rolled while it is adhered, if it is rolled, it peels off during rolling and adheres to the base material other than the joints, causing biting defects. Become a cause. Therefore, in the present invention in which the burrs are left, it is important to remove the spattered deposits 14 with a deburring device.

In the present invention, the burrs are formed by detecting the burrs after the burrs are removed by leaving a height of 5% or more of the thickness of the rolled material, and detection is performed by the detecting means after the rolling. Is possible. On the other hand, if the spatters 14 on the surface of the burrs after bonding remain, the spatters will peel off during rolling and cause defects in the base material.

When the cutting edge of the cutting tool is pressed against the rolled material by an elastic supporting mechanism, and the cutting edge of the cutting tool receives a reaction force from the rolling material, a distance from the rolling material increases according to the magnitude of the reaction force. can do. With such an elastic support mechanism, the spattered substances 14 adhering to the surface of the rolled material other than the raised portions of the burrs are surely removed by the cutting blade, and the raised portions of the burrs are caused by the reaction force of the burrs. The cutting edge of the cutting tool is retracted, and the burr can be removed while leaving the base of the burr. The spring constant of the support mechanism for the cutting blade can be determined based on experiments so that the remaining height of the burrs falls within the above-described appropriate range.

A method and an apparatus for detecting a joint according to the second and sixth aspects of the present invention will be described. In the flash butt welding, a sound joining having a sufficient joining force can be performed over the entire joining surface by pressing the rolled material with a sufficient pressing force. On the other hand, when the pressing force is reduced, a portion where bonding is insufficient occurs in a part of the bonding surface. If the area ratio of the insufficiently bonded surface to the entire bonded surface is small, there is no trouble that the bonded portion breaks during rolling. In addition, a portion where bonding is insufficient has flaws remaining after the subsequent rolling, and can be detected by the flaw detecting means after the rolling. As the flaw detecting means, the same means as in the first invention can be used.

Taking the case where a steel billet is rolled as a rolled material as an example, if the area ratio of the insufficiently bonded surface to the entire bonded surface is 20% or less, a problem occurs that the bonded surface is broken in rolling. Never. On the other hand, when the area ratio is 2
%, The flaw remaining after rolling is too small, and it may be difficult to detect the flaw by the flaw detecting means.

The smaller the pressing force of the flash butt welding, the larger the area ratio of the insufficiently joined surface. Therefore, the appropriate range of the pressing force can be determined by an experiment so that the area ratio of the surface with insufficient bonding falls within the appropriate range. When a steel billet is rolled as a rolled material, the appropriate range is 2-3 kg / mm ^2.
Met.

A method and an apparatus for tracking a rolled material joint according to the third and seventh aspects of the present invention will be described. Regarding the fixed point A before the rough rolling mill, the distance from the fixed point A to the entrance of the rough rolling mill 4 is set to be shorter than the length of the rolled material 11, so that the fixed point A
When the rear end 16 of the rolled material 11 passes, the front end 17 of the rolled material 11 is already in a state of being bitten by the rough rolling mill (see FIG. 4A). On the other hand, by setting the fixed point A to be closer to the heating furnace 1 than the joining start position of the running joining apparatus 2, when the rear end 16 of the rolled material 11 passes the fixed point A, the joining with the succeeding material is not performed yet. Instead, the time at which the rear end of the rolled material passes the fixed point A can be measured by the rolled material detection device 9.

At the fixed point B after the completion of the rolling, the rolled material 11
By measuring the time when the rear end 16 passes (see FIG. 4B), the time T from when the rear end 16 of the rolled material 11 passes the fixed point A to when it passes the fixed point B is measured. Can be. However, if the rear end of the rolled material is joined to the front end of the succeeding rolled material, it is not possible to measure the rear end passing time at the fixed point B. Therefore, the rolling of the rolled material 11 for measuring the time T must be performed not by continuous rolling but by discontinuous rolling.

If the time T of the leading rolled material can be measured in this way, the succeeding rolled material employing the same rolling conditions can be used after the predetermined point (in this case, the joining portion) has passed the fixed point A and the fixed point B Can also be predicted to be the time T. That is, the time at which the rear end of the rolled material that has started rolling has passed the fixed point A is measured, and after a lapse of time T from that time, the rear end of the rolled material (the joined portion joined to the subsequent material) is fixed. The joint can be tracked by predicting that it will reach B.

The speed at which the rolled material is transferred from the heating furnace to the rolling mill before the start of rolling can vary from rolled material to rolled material. If the rolled material moves at a transport speed that receives the fluctuation even after passing through the fixed point A, the time required from the fixed point A to the fixed point B varies under the influence of the transport speed of the rolled material. For this reason, in the preferred embodiment, the fixed point A is located at a position shorter than the length of the rolled material from the entrance of the rolling mill. When the rear end of the rolled material reaches the fixed point A, the rolled material has already started rolling, so that it is not affected by a change in the transport speed before rolling. Of course, if the transport speed of the rolled material before rolling is maintained equal to the rolling speed of the first stage of the rolling mill, the fixed point A may be separated from the rolling mill by a distance equal to or longer than the length of the rolled material.

In order to obtain tracking information using the rear end 16 of the first rolled material, it is necessary to make the first rolled material discontinuous as described above. On the other hand, if the tracking information is obtained using the leading end 17 of the leading rolled material, the tracking information can be obtained even if the leading rolled material is continuously rolled. In this case, the transport speed between the time when the leading end of the leading rolled material passes through the fixed point before rolling and the time when the leading end of the material rolls into the rolling mill can vary for each rolled material. Therefore, if the fixed point A before the joining start position is used as described above, accurate tracking information may not be obtained due to the influence of the transport speed of the leading rolled material. Therefore, when tracking information is obtained using the leading end of the leading rolled material, a fixed point C is provided immediately before the rough rolling mill so as to minimize the influence of the change in the transport speed, and the leading end of the leading rolled material is located at the fixed point C. The tracking information is obtained by measuring the time T 'from the passing to the passing of the fixed point B after the end of the rolling.

On the other hand, in order to track the joint after the second continuous rolling, it is necessary to measure the time at which the rear end 16 of the rolled material 11 before joining passes a predetermined fixed point. At the fixed point C immediately before the rough rolling mill, since the joining has already been completed, the time when the rear end passes the fixed point C cannot be measured.
Therefore, the time when the rear end of the rolled material passes through the fixed point A, which has not been joined yet, is measured. The time from when the predetermined position (joint) passes through the fixed point A to when it passes through the fixed point B can be obtained by correcting the measured time T ′. Since the speed V1 of the rolled material immediately before the rough rolling is fixed if the rolling conditions are constant, a number obtained by multiplying the distance L1 from the fixed point A to the fixed point C by V1 using the speed V1 is used as the time T ′. In addition, the estimated required time from when the joint passes through the fixed point A to when it passes through the fixed point B can be obtained.

With the above tracking method, it is possible to predict the time at which the joint 12 passes the fixed point B after the rolling is completed. The fixed point B is a position for measuring the time at which the rear end or the front end of the leading rolled material passes, and is a position provided with the joint detection means, but the place where it is desired to predict the time at which the joint actually passes, This is at the joint marking means or the joint cutting means arranged at the fixed point D after the joint detection, which is a different position from the fixed point B. The time required for a predetermined position (joined portion) of the rolled material to pass from the fixed point B to pass the fixed point D is determined by using a distance L2 from the fixed point B to the fixed point D and a finished rolled material conveying speed V2, L2 × V2
Can be obtained as By using this means, the time from when the rear end of the rolled material before the joining in continuous rolling passes the fixed point A before the rough rolling mill to when the joint at the rear end of the rolled material reaches the fixed point D is predicted. can do.

A method and an apparatus for tracking a rolled material joint according to the fourth and eighth aspects of the present invention will be described. The present invention will be described with reference to FIG. FIG. 6 is a diagram showing a change over time of the detection signal of the joint detecting means of the present invention. As detection signals, a joint detection signal 21 based on artificial flaws added to the joint and a natural flaw detection signal 22 based on other natural flaws are detected. Here, a time width 20 is provided before and after the predicted joint arrival time 18 predicted by the tracking method / apparatus of the third and seventh aspects of the present invention, and it is predicted that the joint 12 arrives within the range of the time width 20. If a detection signal equal to or greater than the predetermined threshold value 23 is obtained in the range of the time width 20, the time when the signal is obtained is set to the joint detection time 1
Recognize as 9 and correct the tracking.

Even if the detection signal is within the range of the time width 20, the signal below the threshold value 23 is recognized as a natural flaw. Even if the signal is equal to or greater than the threshold value 23,
If it is detected at a time outside the range of the time width 20, it is also recognized as a natural flaw.

To avoid erroneous recognition that a natural flaw is a joint, the shorter the time width 20 for detecting a signal, the better. On the other hand, when the difference between the predicted arrival time of the joint by the tracking and the actual arrival time is large, if the time width 20 is too short, the actual joint is out of the range of the time width, and the joint is recognized. There are cases where it is not possible.
Therefore, as for the time width 20, it is desirable to determine the optimum time width in consideration of the variation between the predicted tracking time and the actual arrival time. As for the threshold value 23 of the detection signal, the joint detection signal 21 due to the artificial flaw of the joint and the natural flaw detection signal 22 are actually compared to minimize the occurrence of the joint detection failure and the occurrence of the erroneous detection. It is desirable to determine the optimal value to perform.

As the predicted arrival time 18 at which the joint reaches the detecting means, the result of the method of the third invention is used for the joint at the beginning of continuous rolling. Can use the result of tracking performed on the joined portion of the preceding rolled material. Thus, even when the rolling conditions gradually change as the rolling progresses, it is possible to track the joint while accurately capturing and correcting the change.

[0049]

EXAMPLE The present invention was carried out in continuous rolling of a steel wire rod. As the rolled material 11, a billet having a size of 122 mm × 18 m was used. The running joining device 2 is arranged between the heating furnace 1 and the rough rolling mill 4, and the running joining device 2 and the rough rolling mill 4 are further arranged.
And the deburring device 3 is arranged between them. The wire rod is processed into a wire rod through a rough rolling mill 4, an intermediate rolling mill 5, and a finishing rolling mill 6, and is sent to a convergence device 8 through a winding device 24 and an adjusting cooling device 7. The joint detection means 10 is arranged behind the finishing mill 6.

Flash butt welding was used for joining the end faces of the rolled material 11 extracted from the heating furnace 1. Join 2
The billet of the book is gripped by a gripping device also serving as an electrode, and then flash butt welding is performed. The short-circuit current between the electrodes
The conditions were 10 A / mm ² , the no-load voltage between the electrodes was 5 to 30 V, and the platen moving speed was 1 to 5 mm / sec. In order to obtain a healthy joint, the joint surface pressure should be 4 kg /
mm ² or more.

A hot eddy current flaw detector was used as the joint detecting means 10 after the finishing mill 6.

The fixed point A is set at a position closer to the heating furnace 1 than the joining start position of the running joining device 2 and at a position 12 m from the entrance of the rough rolling mill 4. Means 9 for optically detecting the presence or absence of a rolled material at fixed point A
Having. The fixed point C is arranged 3 m before the entrance of the rough rolling mill 4 and also has means for optically detecting the presence or absence of a rolled material. The fixed point B is arranged at the same position as the joint detecting means 10 behind the finishing mill, and has means for optically detecting the presence or absence of a wire passing through the fixed point B. The fixed point D is located at the same position as the converging device 8, and has means for cutting the joint end of the rolled material and removing the joint.

The deburring device 3 arranges the bit of the cutting tool along the rolled material, and the rolled material moves along with the rolling, so that the bit of the bite cuts the burr and removes the burr.

In the first invention, a sound joining portion was formed by setting the joining surface pressure of the flash butt welding to 5 kg / mm ² . At this time, the height of the burr 13 generated at the joint 12 is about 14 mm. In addition, on the surface in the vicinity of the joint portion 12, a splashed deposit 14 due to flash is attached. In deburring, burrs were removed leaving a height of 10 mm. At the same time, all the droplets 14 were removed. By setting the pressing force for pressing the bit of the cutting tool against the rolled material at 3 kg / mm per unit length of the bit of the cutting tool, the target burr could be removed.

After the burrs were partially removed and removed as described above, rolling was carried out, and the joined portions were detected by the joined portion detecting means 10 after the rolling. The remaining burrs were turned into fold flaws 15 by rolling and could be detected by the joint detecting means 10. However, when a large natural flaw occurs in the base material portion of the rolled material, the natural flaw may be erroneously recognized as a joint.

In the second invention, the joining surface pressure of the flash butt welding was set to 2.5 kg / mm ^2, and the joining was performed by causing a defect in the joining portion. When the area ratio of the insufficiently bonded surface to the entire bonded surface was measured by the X-ray transmission method, the area ratio was about 4%. As described above, when the rolling was performed with the joints having defects, no trouble occurred in which the joints were broken.
With 0, the joint could be detected. When a large natural flaw occurred in the base material portion of the rolled material, the natural flaw was sometimes erroneously recognized as a joint, as in the first invention.

In the third aspect of the invention, the time T was measured, and tracking of the junction was performed using the time T. When the dispersion of the difference between the predicted time based on the time T and the time when the joint actually arrived at the fixed point B in one continuous rolling was evaluated,
The prediction could be made with a variation of standard deviation (σ) = 0.25 seconds.

Similarly, in the third invention, the time T 'was measured, and tracking of the joint was performed using the time T'. The variation from the predicted time was standard deviation (σ) = 0.5 seconds.

In the fourth invention, the method of detecting burrs according to the first invention is used as a method for detecting a joint. In addition, the first joint predicted arrival time of continuous rolling is tracked using the means for measuring the time T of the third invention, and the joint predicted arrival time for tracking the second and subsequent joints of continuous rolling is used. For tracking, the tracking result corrected by the fourth invention for the immediately preceding joint was used. The time range to set before and after the forecast time is
1.5 seconds was employed on one side. As the threshold value, a value of 60% of the average value of the detection signal height of the artificial flaw at the joint was used.

As a result of implementing the fourth invention under such conditions, the joint can be reliably detected.

[0061]

By using the joint detection method, the joint tracking method and the apparatus of the present invention in continuous rolling, the joint can be reliably formed even when continuous rolling is performed using a rod-shaped rolled material. , And it is possible to reliably remove the joint after rolling.

[Brief description of the drawings]

FIG. 1 is an overall view of a rolling facility using the present invention.

FIG. 2 is a cross-sectional view showing a state of occurrence of burrs after rolling material joining.

FIG. 3 is a partial cross-sectional view showing folding flaws after burr is rolled.

4A and 4B are diagrams for explaining a situation where time T is measured by the tracking method of the present invention, and FIG.
(B) shows the time when the rear end of the rolled material passes through the fixed point B.

5A and 5B are diagrams illustrating a situation in which time T ′ is measured by the tracking method of the present invention, wherein FIG. 5A shows a time when the leading end of a rolled material passes a fixed point C, and FIG. Indicates the time of passage.

FIG. 6 is a diagram showing a situation in which tracking is corrected based on a flaw detection signal by the tracking method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Running joining device 3 Deburring device 4 Rough rolling mill 5 Intermediate rolling mill 6 Finishing rolling mill 7 Adjusting cooling equipment 8 Converging device 9 Rolled material detecting device 10 Joint detecting means and rolled material detecting device 11 Rolled material 12 Joint 13 Burr 14 Spattered matter 15 Folding flaw 16 Rear end 17 Tip 18 Predicted arrival time of joint 19 Actual joint detection time 20 Time width 21 Joint detection signal 22 Natural flaw detection signal 23 Threshold value 24 Winding device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B23K 11/04 102 G01N 27/82 11/24 345 29/22 // G01N 27/82 B21B 37/00 BBG 29/22 136A (72) Inventor Toshiharu Obimu 23-15 Suzukocho, Kamaishi Nippon Steel Corporation Kamaishi Works (72) Inventor Makio Kikuchi 2-6-3 Otemachi, Chiyoda-ku, Tokyo New Japan F-term (reference) in Iron Corporation 2G047 AA06 AB04 AB07 AD11 BC07 DB16 EA10 GG33 GJ22 2G053 AA11 AA26 AB21 BA15 BA30 BB08 BB18 CC03 4E002 AC14 BD05 4E024 AA10 FF01

Claims (20)

[Claims] 1. A method for detecting a joined portion after joining and rolling a preceding material and a succeeding material in continuous rolling, wherein a part of the burr is removed when burrs generated in the joining are removed before rolling. An artificial flaw is generated in the joint by removing the artificial flaw, and the joint is detected by detecting the artificial flaw by the joint detecting means after finish rolling. 2. The method according to claim 1, wherein when removing the burrs, splashing deposits of the flash butt welding are removed, and the burrs are removed while leaving the rolled material bulging portion at the joint.
3. The method for detecting a joint according to claim 1. 3. The tool for removing burrs according to claim 2, wherein when receiving a reaction force from the rolled material, the cutting tool is separated from the center of the rolled material in accordance with the magnitude of the reaction force. Joint detection method. 4. A method for detecting a joined portion after joining and rolling a preceding material and a succeeding material in continuous rolling, wherein the joining includes a defect in the joined portion to such an extent that the joined portion does not break during rolling. A joint detection method comprising: performing jointing to generate an artificial flaw in the joint; and detecting the joint by detecting the artificial flaw by the joint detecting means after finish rolling. 5. The joint detection method according to claim 4, wherein the size of the defect at the joint is adjusted by adjusting the pressing pressure between the preceding material and the following material during the flash butt welding. . 6. The time T from when the rear end of the rolled material after the start of rolling passes the fixed point A before the rough rolling mill to when it passes the fixed point B after the end of rolling is previously confirmed by discontinuous rolling. Continuous rolling, wherein the time from when the rear end of the rolled material before joining passes through the fixed point A to when the joint at the rear end of the rolled material reaches the fixed point B is predicted using time T. Rolled material joint tracking method. 7. A time T 'from when the leading end of the rolled material immediately before the start of rolling passes the fixed point C immediately before the rough rolling mill to when it passes the fixed point B after the end of the rolling is previously checked, and the rolling before the continuous rolling is joined. The time from when the rear end of the material passes the fixed point A in front of the rough rolling mill to when the joint at the rear end of the rolled material reaches the fixed point B is defined as time T ′, the distance L1 from the fixed point A to the fixed point C. And a rolling material joint tracking method for continuous rolling, wherein the prediction is performed using the speed V1 of the rolled material immediately before rough rolling. 8. The method according to claim 6, wherein the joint at the rear end of the rolled material passes a fixed point B after the end of rolling and then the fixed point after the end of rolling. By predicting the time to reach D using the distance L2 from the fixed point B to the fixed point D and the finished rolled material transport speed V2, the rear end of the rolled material before joining in the continuous rolling is positioned before the rough rolling mill. A method of tracking a rolled material joint in continuous rolling, comprising estimating a time from when the fixed point A passes to when the joint at the rear end of the rolled material reaches the fixed point D. 9. A method for predicting a time required for a joint to reach a position of a joint detecting means after finish rolling using the method for tracking a joint of a rolled material in continuous rolling according to claim 6;
A position where a flaw signal equal to or more than a predetermined threshold value is obtained by the joint detecting means of the joint detecting method according to any one of claims 1 to 5, within a predetermined time width before and after the predicted time. A tracking method for a rolled material joint in continuous rolling, characterized in that tracking is corrected by judging a part as a part. 10. A time required for a joint to reach a position of a joint detecting means after finish rolling is predicted in advance using a tracking result performed on a joint of a preceding rolled material, and a predetermined time before and after the predicted time is determined. The position where the flaw signal equal to or larger than the predetermined threshold value is obtained by the joint detecting means of the joint detecting method according to any one of claims 1 to 5 within the range of the determined time width is determined as the joint and the tracking is corrected. A method of tracking a rolled material joint in continuous rolling. 11. A joint detecting apparatus for detecting a joint after joining and rolling a preceding material and a succeeding material in continuous rolling, wherein a part of the burr is removed when removing a burr generated in the joining. A deburring means for generating an artificial flaw in the joint by removing the joint and a joint detecting means for detecting the artificial flaw disposed on the rear surface of the finish rolling and detecting the artificial flaw. Part detection device. 12. The deburring means for removing burrs only when flash butt welding is removed and removing the burrs while leaving a raised portion of the rolled material at the joint. 3. The joint detection device according to claim 1. 13. The tool for removing burrs according to claim 12, wherein when receiving a reaction force from the rolled material, the cutting tool is separated from the center of the rolled material according to the magnitude of the reaction force. Joint detection device. 14. A joint detecting device for detecting a joint after joining and rolling a preceding material and a succeeding material in continuous rolling, wherein the joining is performed to such an extent that the joint does not break during rolling. It is characterized in that it has a joining means for performing a joint that causes a defect to generate an artificial flaw in the joint, and a joint detecting means for arranging the joint on the rear surface of the finish rolling and detecting the artificial flaw by detecting the artificial flaw. And a joint detecting device. 15. The joint according to claim 14, wherein the joining means adjusts the size of the defect at the joint by adjusting the pressing pressure between the preceding material and the following material during the flash butt welding. Junction detection device. 16. A means for measuring the time at which the rear end of the rolled material after the start of rolling passes the fixed point A before the rough rolling mill, and measuring the time at which the rear end of the rolled material passes the fixed point B after the end of rolling. Means, and the time T from when the rear end of the rolled material passes through the fixed point A to when it passes the fixed point B is previously confirmed by discontinuous rolling, and the rear end of the rolled material before joining of the continuous rolling is the aforementioned After passing the fixed point A, the joint at the rear end of the rolled material is fixed at the fixed point B
Characterized in that it has a calculating means for predicting the time until the temperature reaches the time T using the time T. 17. A means for measuring the time at which the leading end of the rolled material immediately before the start of rolling passes the fixed point C immediately before the rough rolling mill, and the time at which the trailing end of the rolled material after the start of rolling passes the fixed point A before the rough rolling mill. And a means for measuring the time when the leading end of the rolled material passes the fixed point B after the end of rolling, and further, the rolling end is performed after the leading end of the rolled material passes the fixed point C immediately before the rough rolling mill. The time T 'before passing the fixed point B later is checked in advance, and after the rear end of the rolled material before the joining of the continuous rolling passes the fixed point A before the rough rolling mill, the joint at the rear end of the rolled material is The continuous rolling method is characterized in that it has a calculating means for predicting the time to reach the fixed point B using the time T ′, the distance L1 from the fixed point A to the fixed point C, and the speed V1 of the rolled material immediately before the rough rolling. Rolled material joint tracking device. 18. The rolling material joint tracking device for continuous rolling according to claim 16 or 17, wherein the joint at the rear end of the rolled material passes a fixed point B after the rolling is completed, and then the fixed point after the rolling is completed. D which has a calculating means for predicting the time to reach D using the distance L2 from the fixed point B to the fixed point D and the finished rolled material transport speed V2, and the rear end of the rolled material before joining in the continuous rolling is rough-rolled. A rolling material joint tracking device for continuous rolling, wherein a time from when a fixed point A in front of the machine is passed to when the joint at the rear end of the rolled material reaches the fixed point D is predicted. 19. A tracking device for a rolled material joint in continuous rolling according to claim 16, wherein the tracking device comprises:
5 has a joint detection device according to, further, the time it takes the joint to reach the position of the joint detection means after finish rolling, using a rolled material joint tracking device of the continuous rolling in advance to predict, Within a range of a predetermined time width before and after the predicted time, a position where a flaw signal equal to or greater than a predetermined threshold value is obtained by the joint detection means of the joint detection device is determined as a joint, and tracking is corrected. A continuous tracking device for tracking a joint of a rolled material, comprising a calculating means. 20. A joint detecting apparatus according to claim 11, further comprising: a time for the joint to reach the position of the joint detecting means after finish rolling is determined for the joint of the preceding rolled material. Predicted using the tracking result, within a predetermined time width before and after the predicted time,
Rolled material for continuous rolling, characterized by having a calculating means for judging a position where a flaw signal equal to or more than a predetermined threshold value is obtained in the joint detecting means of the joint detecting device as a joint and correcting the tracking. Joint tracking device.