JP2008030046A - Steel strip butt welder - Google Patents

Abstract

An object of the present invention is to reduce undiscovered welding breaks and poor welds in a flash butt type steel strip butt welder, and to avoid line stoppages and production failures in continuous processing equipment for steel strips.
The present invention relates to a flash butt welder installed in a continuous processing equipment for a steel strip, and includes an electrode table 2 for holding and clamping the rear end of a preceding steel strip, and a holding clamp for the front end of a subsequent steel strip. A measuring means 5 such as a laser displacement meter is attached to the electrode table 3 that moves toward the other electrode table 2 among the electrode tables 3 that are present, and the level fluctuation of the moving electrode table 3 is continuously detected while arcing. To do. As a result, it has become possible to accurately grasp the occurrence of poor welding, which has conventionally been unknown.
[Selection] Figure 2

Description

  TECHNICAL FIELD The present invention relates to a steel strip butt welder that is disposed on the entry side of a steel strip continuous processing facility and that continuously welds steel strips to perform butt welding.

  A welding machine that automatically butt-welds the steel strip and continuously processes it is installed on the entrance side of the continuous processing equipment for the steel strip. Among them, as shown in FIG. 1, the flash butt butt welding machine includes an electrode base 2 for holding and clamping the rear end of the preceding steel strip on the base 1, and an electrode base 3 for holding and clamping the front end of the subsequent steel strip. It is provided. In this example, the electrode base 3 that holds and clamps the tip of the trailing steel strip is brought close to the other electrode base 2 by the cylinder 4, and arc discharge is performed between the steel strips to perform welding.

  However, if there is a problem with this butt welding, the steel strip may break from the welded joint in the continuous processing equipment, leading to a line stop. Moreover, even if it does not break, the steel strip meanders due to welding defects, and the plate passing speed has to be reduced, or the equipment may be damaged by meandering. For this reason, while improving the reliability of a welding machine, the technique which monitors whether various conditions regarding welding were performed as set is developed.

  For example, in Patent Document 1, the amount of butting at both ends in the width direction of the steel strip is measured at the start of arc generation, at the start of upset, and at the end of upset, and compared with the set value, the presence or absence of abnormality in flash butt butt welding is determined. A method of detecting is disclosed. Patent Document 2 discloses a method of detecting a welding current, a welding voltage, a welding speed, a pressing force, and the like, and detecting the presence / absence of seam welding abnormality in comparison with a set value.

However, in the flash butt butt welding machine that welds while arcing between steel strip ends, the butt amount, welding current, welding voltage, welding speed, etc. as shown in Patent Documents 1 and 2 are all set values. Even if it is true, there may be cases where welding breakage or welding failure occurs, causing line stop and the like.
JP-A-2-84278 JP-A-5-161980

  The present invention solves the above-mentioned conventional problems, reduces unexplained welding breaks and poor welds in flash butt type steel strip butt welders, and prevents line stoppages and production failures in continuous processing equipment for steel strips. It is an object of the present invention to provide a steel strip butt welder that can be avoided.

  As a result of investigating the welding behavior in a flash butt butt welder in detail to solve the above-mentioned problems, the inventor moved the electrode table holding the end of the steel strip while arc discharge, It has been clarified that welding becomes non-uniform because the electrode stage causes a minute level fluctuation and the discharge part between the end portions of the steel strip fluctuates accordingly.

  The present invention has been completed on the basis of the above knowledge, and is a steel strip butt welding machine installed in a continuous processing facility for a steel strip, holding and clamping the rear end of the preceding steel strip. Measurement that detects the level fluctuation of the moving electrode table while arcing to the electrode table that moves toward the other electrode table among the electrode table and the electrode table that holds and clamps the tip of the trailing steel strip. Means is provided.

  It is preferable to provide the above-mentioned measuring means at a plurality of positions of the electrode table, and it is provided with a welding condition monitoring device for accumulating level fluctuation data during movement of the electrode table detected by the measuring means and analyzing the change over time. preferable. In addition, it is preferable to include means for detecting at least one of the moving speed of the electrode table, the cylinder pressure for moving the electrode table, the cylinder back pressure for moving the electrode table, and the welding current.

  The steel strip butt welder of the present invention is equipped with a measuring means for detecting the level fluctuation of the moving electrode table while arcing, and therefore a level fluctuation that causes welding failure occurred. In some cases, an alarm can be issued immediately. One of the causes of the level fluctuation is that welding spatter adheres to the traveling surface of the electrode table, and can be eliminated by cleaning the traveling surface. For this reason, it is possible to reduce unexplained welding breaks and welding defects in flash butt type steel strip butt welders, and can greatly contribute to line stop of continuous processing equipment for steel strip and avoidance of production failures. It became.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
In FIG. 2, reference numeral 1 denotes a pedestal of a flash butt welder installed in a steel strip continuous processing facility. An electrode base 2 that holds and clamps a rear end of a preceding steel strip on its running surface, and a trailing steel strip An electrode table 3 that holds and clamps the tip is mounted. Each of the electrode bases 2 and 3 is clamped by projecting the tip of the steel strip by about several millimeters, making it approach while blowing an arc between them, and melting the tip to perform welding. In this example, the electrode base 2 that holds and clamps the rear end of the preceding steel strip is fixed, and the electrode base 3 that holds and clamps the front end of the subsequent steel strip is approached by the cylinder 4 toward the electrode base 2. ing. However, the electrode table 3 may be fixed and the electrode table 2 may be moved, or both the electrode tables 2 and 3 may be moved.

  The method for measuring the level fluctuation during the movement of the electrode table is not particularly limited. In this embodiment, however, the level fluctuation is detected at a position where the fluctuation can be measured most accurately when the electrode table 3 moves. Means 5 are provided to continuously measure the distance between the electrode base 3 and the base 1. As the measuring means 5, a laser displacement meter, a proximity distance meter, a gauge meter or the like can be used. The measuring means 5 detects the level fluctuation while the electrode base 3 moves while arcing, and outputs it to the welding condition monitoring device 6. The level fluctuation is preferably continuously measured at least during the arc discharge.

  The measuring means 5 may be single, but is preferably provided at a plurality of locations on the electrode table 3 in order to increase detection accuracy. For example, it is preferable to install and measure and monitor both sides of the steel strip to be welded (work side (WS) and drive side (DS)) and before and after the moving electrode table 3. It is also preferable to install a plurality of them at the same location for fail-safe and detection accuracy improvement.

  Further, it is also preferable to accumulate the level fluctuation data during movement of the moving electrode table 3 in the welding condition monitoring device 6 and grasp the change over time of the level fluctuation during movement of the moving electrode table 3. By grasping the change over time of the level fluctuation in this way, it becomes possible to grasp the deterioration over time of the electrode table moving device, for example, the electrode table moving wheel, rail, pedestal, etc. It becomes possible to investigate the cause of

  As shown in FIG. 2, in addition to the level fluctuation during the movement of the electrode table, the moving speed of the electrode table 3, the pressure of the cylinder 4 for moving the electrode table, the back pressure of the cylinder 4 for moving the electrode table, the welding current, the welding Means for detecting at least one of the voltages can be provided, and the presence or absence of welding abnormality can be detected along with the level fluctuation. Moreover, you may add the diagnosis of a welding part by flaw detection apparatuses, such as an ultrasonic wave and an overflow flaw detection, and ITV.

  3 and 4 show the welding voltage and welding current detected in this way, the level fluctuation (distance from the base) when the electrode base moves, the electrode base moving speed, the electrode base moving cylinder pressure, and the electrode base movement. A chart of cylinder back pressure is shown. FIG. 3 is a measurement result chart when normally welded, and FIG. 4 is a measurement result chart when a fracture after welding occurs. In both figures, the welding conditions were almost the same except for the level fluctuation during the movement of the electrode base, but in FIG. 4, the fracture occurred after welding, the equipment stopped and the production was interrupted.

  As a result of continuing the investigation over a predetermined period regarding the level fluctuation during the electrode table movement and the presence or absence of welding abnormality, the inventors have found that the welding current, electrode table moving speed, electrode table moving cylinder pressure and back pressure abnormality are not present. It was found that there was an abnormality in the level fluctuation during the electrode stage movement similar to that in FIG. As shown in FIG. 4, just before the end of the steel strip abuts, the level of the moving electrode table fluctuates greatly and is welded. It has been confirmed that the level change during arc discharge leads to poor welding.

  As described above, according to the butt welder according to the present invention, it is possible to prevent welding troubles such as welding breakage from the conventional butt welder, so that the metal strip manufacturing equipment, For example, it is suitable for a steel strip rolling mill and a welding machine on the pickling equipment entry side.

It is explanatory drawing which shows the conventional butt welding machine of a steel strip. It is explanatory drawing which shows the butt welding machine of the steel strip of this invention. It is a measurement result chart at the time of welding normally. It is a measurement result chart at the time of becoming poor welding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Electrode stand holding and clamping the rear end of a preceding steel strip 3 Electrode stand holding and clamping the front end of a subsequent steel strip 4 Cylinder 5 Measuring means 6 Welding condition monitoring device

Claims (4)

  A steel strip butt welder installed in a continuous treatment facility for steel strips, an electrode table holding and clamping the rear end of the preceding steel strip, and an electrode holding and clamping the tip of the subsequent steel strip A steel strip butt welder characterized in that a measuring means for detecting level fluctuations of the moving electrode table while arc discharge is provided on the electrode table moving toward the other electrode table.   The steel strip butt welder according to claim 1, wherein the measuring means is provided at a plurality of locations on the electrode base.   The steel strip butt according to claim 1 or 2, further comprising a welding condition monitoring device for accumulating level fluctuation data during movement of the electrode table detected by the measuring means and analyzing changes with time. Welding machine.   2. The apparatus according to claim 1, further comprising means for detecting at least one of a moving speed of the electrode table, a cylinder pressure for moving the electrode table, a cylinder back pressure for moving the electrode table, a welding current, and a welding voltage. A butt welding machine for steel strips according to any one of.

Images