JPS623803A - Method and apparatus for treating weld zone of steel strip - Google Patents

Abstract

PURPOSE:To prevent the rupture of a steel strip occurring in the weld zone thereof during cold rolling by detecting the step in the weld zone of the welded steel strip by a weld zone inspecting instrument and cutting away the weld zone when the detected value is above a prescribed value. CONSTITUTION:The weld zone inspecting instrument 14 scans zigzag the region for the grinding width of a bead part 15, measures the distance between the steel strip 2 and the inspecting instrument 14 and calculates a step quantity DELTAt from the difference between the detected distances of both steel strips 2 sandwiching the weld zone. The weld zone is coiled and taken up to the capacity limit of a tension reel if the step DELTAt in each part measured by the inspecting instrument 14 is below the prescribed quantity and the weld zone is cut away by operating a shear 13 if the step is above the prescribed quantity. The coiled steel strip 2 taken up on the tension reel 12 is thereafter conveyed to a cold tandem rolling line and is thereby rolled. The generation of the sheet rupture by the braking effect is thus prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for treating a welded part of a steel strip in a continuous pickling line or a continuous cold tandem rolling mill, and a method for treating a welded part of a steel strip in a continuous pickling line or a continuous cold tandem rolling mill. Regarding the device.

[Conventional technology]

Generally, a hot rolled steel strip is chemically removed from surface oxide scale in a continuous pickling line, and then cold rolled to a predetermined thickness in a cold tandem rolling mill.

Incidentally, the tandem rolling mill is being increasingly made continuous with the aim of improving production capacity and yield. That is,
In the case of batch rolling, off-gauge occurs when the steel strip is accelerated or decelerated, but in continuous rolling, this off-gauge amount can be reduced and production capacity can be increased by being able to roll continuously. be able to. Continuous rolling can be achieved by disposing a welder and a looper on the entry side of a tandem rolling mill to control the conveyance speed of the steel strip.

In a continuous pickling line having such a continuous tandem rolling mill on the downstream side, welds of the steel strip pose a problem. In other words, in order to carry out continuous pickling in the pickling line, the steel strip is welded using a welding machine on the inlet side of the line, but conventionally, this welded part was cut and removed using a shear on the outlet side of the pickling line. It is then rolled up and fed to a batch-type tandem rolling mill.As tandem rolling became more continuous, the pickling line was installed at the exit side of the tandem rolling mill without cutting the welded part. It is more efficient to wind the product up to the winding capacity of the exit tension reel and supply it to the continuous tandem rolling mill.

[Problem that the invention seeks to solve]

However, in the above conventional method, if a vertical step occurs in the weld, the braking effect of this step may cause the steel strip to break during tandem rolling, and it takes a lot of effort to recover. There is a problem in that it requires labor and time and also causes a major hindrance to productivity.

Therefore, the present invention has been made by focusing on the above-mentioned problems of the conventional method, and when the steel strip is continuously cold rolled in a tandem rolling mill after pickling treatment, the steel strip breaks at the welded part. It is an object of the present invention to provide a method for treating a welded part of a steel strip and an apparatus therefor, which can prevent such problems and smoothly perform cold rolling.

[Means for solving problems]

In order to achieve the above object, the present invention inspects the level difference in the welded part of the steel strip welded in the pickling line when the steel strip is pickled and then subjected to cold tandem rolling. A method for treating a welded part of a steel strip characterized by cutting and removing the welded part before performing the cold tandem rolling when the welded part is greater than or equal to the above cold tandem rolling is defined as a specified invention, and a welding machine for a continuous pickling line for steel strip. A welding part inspection device for detecting the amount of step in the steel strip weld is disposed between the shear and the exit shear, and when the detection result of the welding part inspection device is that the amount of step is more than a predetermined amount, the welded part is inspected. A combined invention is a welded part processing apparatus for a steel strip, characterized in that a control device is provided for activating the exit shear to cut and remove the welded part of the steel strip when the steel strip reaches the exit shear position. It is something.

[Effect]

In this invention, when there is a step in the welded part of the steel strip welded on the entrance side of the continuous pickling line, this is detected and the welded part is cut and removed by a shear.
Steel strip breakage due to welds during cold rolling in a continuous tandem rolling mill can be prevented.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an example of a continuous pickling line to which the present invention can be applied, in which a steel strip 2 wound around a payoff reel 1 is unwound by a feed leveler 3, and then is unwound by a crop shear 4. After removing the defective part with flash butt well goo 5 and joining it with the tail end of the preceding steel strip, and grinding the weld bead, the inlet looper 6, tension leveler 7, pickling tank 8, The coil passes through a side looper 9, a side trimmer 10, and an oiler 11, and is wound onto a tension reel 12, and when the outer diameter of the coil reaches a predetermined value, it is cut by a shear 13 disposed on the inlet side of the tension reel 12.

Then, a welding part inspection device 14 for detecting a step in the welded part of the rope strap 2 is installed either between the exit side looper 9 and the side trimmer 10 on the entry side of the shear 13 or between the side trimmer 10 and the shear 12. It is arranged.

This welding part inspection device 14 is comprised of, for example, a non-contact laser distance meter. The bead 1 portion 15 of the steel strips joined by the welder 5 is ground into an arc shape by a flash trimmer (not shown) as shown in FIG. 2(b). State T where 2 are flush: It is difficult to weld, and a step Δt occurs between the two. If the step amount Δt exceeds a predetermined amount, breakage trouble will occur in the cold tandem rolling mill due to the braking action, so it is necessary to detect it carefully and with high precision.

Therefore, the welding part inspection device 14 scans an area of about 50 to 751 widths sandwiching the grinding width B (10 to 15 dragons) of the leaflet 1 part 15 from one side edge C to the other side edge D by line i.
Measure the distance between the steel strip 2 and the weld inspection device 14 at each scanning position by scanning in a zigzag manner in the order of -, -y,
The step amount ΔL is calculated from the difference in detection distance between the two steel strips 2 that sandwich the welded portion. This step amount Δt is not uniform in the width direction of the bead portion 15, and distortion occurs due to high heat during welding.
It is desirable that the scanning density of the welded part inspection device 14 be as high as possible.

Then, the step difference Δt of each part measured by the welding part inspection device 14
If the amount is less than a predetermined amount, for example, 10% of the plate thickness, the welded portion is wound up to the capacity limit of the tension reel 12, and if it is greater than the predetermined amount, the shear 13 is operated to cut and remove the welded portion. In this case, the welded portion is cut by the shear 12 when the step amount Δt detected by the welded portion inspection device 14 is supplied to the control device 16, and when the step amount Δt is equal to or greater than a predetermined amount, the welded portion is cut by the shear 12. This is automatically performed by stopping the transfer of the steel strip 2 and operating the shear 13 when the section 15 reaches the shear 13 position.

Thereafter, the coiled steel strip 2 wound around the tension reel 2 is conveyed to a cold tandem rolling line, and placed on the payoff reel to perform cold tandem rolling. In this cold tandem rolling, as mentioned above, the welded part where the step amount Δt is more than a predetermined amount is cut and removed, so there is no braking effect in the tandem rolling mill, and stable rolling can be performed. can.

In the above embodiment, a case has been described in which the shear 13 is automatically operated by the control device 16 when the step amount Δt is equal to or greater than a predetermined amount. The shear 13 may be operated manually when the position is reached.

Further, in the above embodiment, the exit side of the looper 9 and the shear 13 are
Although the case where the welding part inspection device 14 is installed between the welding machine 5 and the The welding part inspection device 14 may be disposed on the side.

Furthermore, the welding part inspection device 14 may be installed in front of the entrance welding machine of the continuous tandem rolling mill. In this case, a shear for cutting and removing the welding part 15 may be provided separately, or It is also possible to have a shear built into the machine.

Further, in the above embodiment, the case where the pickling line and the tandem rolling mill are separated has been explained, but the present invention can also be applied to a case where both lines are connected and cold rolling is performed continuously after pickling. Of course.

〔Effect of the invention〕

As explained above, according to the present invention, a step in a welded steel strip welded in a pickling line is detected by a welded part inspection device,
When the detected value is above a predetermined amount, the welded part is cut and removed. This prevents plate breakage due to braking action when cold tandem rolling the steel strip after pickling. This provides the effect that stable rolling can be performed while preventing this, and production efficiency can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, and FIGS. 2(a) and 2(b) are a plan view and a sectional view showing a welded portion of a steel strip, respectively. In the figure, 2 is a steel strip, 5 is a flash barat welder, and 6 is a steel strip.
is the inlet looper, 8 is the pickling tank, 9 is the outlet looper, 12
13 is a tension reel, 13 is an exit shear, 14 is a welding part inspection device, 15 is a welding part, and 16 is a control device.

Claims (2)

[Claims] (1) When the steel strip is subjected to subsequent cold tandem rolling after pickling, the step difference in the welded part of the steel strip welded in the pickling line is inspected, and if the step amount is more than a predetermined value, the A method for treating a welded part of a steel strip, comprising cutting and removing the welded part before performing tandem rolling. (2) A weld inspection device that detects the amount of step in the steel strip weld is placed between the welding machine of the continuous pickling line for steel strips and the exit shear, and the detection result of the weld inspection device indicates the step difference. A control device is provided for activating the exit shear to cut and remove the weld of the steel strip when the weld reaches the exit shear position when the weld is equal to or greater than a predetermined amount. Equipment for processing welded parts of steel strips.