JPH04284911A - Method for passing weld part of bright-finished stock of in-line mill and tension leveler for continuous treatment line - Google Patents

Abstract

PURPOSE:To prevent roll scratches from being generated by passing a bright- finished stock between completely opened mill rolls when the weld part of the bright-finished stock passes a dry temper mill. CONSTITUTION:When the weld part of the bright-finished stock passes the dry temper mill 1, the mill rolls are opened completely from the finished stock to pass it and when the weld part passes the mill rolls and the mill rolls are brought again into contact with the stock, they are brought again into contact with the stock as the stock is stopped to prevent scratches from being occurred. At the same time, when the weld part passes a tension level 2, no touch mark may be generated even though level rollers are brought into contact with the finished stock by selecting adequately an amount of intermesh and a passing speed of the weld part. Thereby, the passing speed is reduced and the intermesh is reduced to the limit of slip to pass the weld part. Consequently, when the weld part passes the dry temper mill 1 and the tension level 2, no scratches are generated by pressing the weld part on the surfaces of the work rolls.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for passing bright finished material welds through an in-line mill or tension leveler installed in a continuous heat treatment line or a continuous surface treatment line.

0002

[Prior art] Continuous heat treatment lines such as CAL, EGL,
In a continuous surface treatment line such as CGL, narrow lap seam welding is performed between the leading material and the trailing material on the line entry side so that steel strip can be continuously supplied.

0003

[Problems to be Solved by the Invention] When a dry temper mill and a tension leveler are installed in the line for in-line dry pressure regulation and finishing, the narrow lap seam welding part is It must pass through a tension leveler.

However, in this narrow lap seam welding, the welded part becomes about 1.2 to 1.8 times the thickness of the plate, and when passing through the above, as shown in FIGS. 8(a) and (b), , First, a load is locally applied to the roll R by this weld A, causing a flaw I on its surface.Furthermore, this flaw on the roll R is transferred to the surface of the steel strip X other than the weld A, resulting in a touch mark M. occurs.

[0005] Even if this touch mark M occurs, the touch mark M cannot be seen due to the influence of diffusely reflected light because the surface of a normal cold rolled steel sheet has a dull finish. With materials that have bright spots left due to materials or laser dull finishing (hereinafter referred to as bright finished materials), the reflected light is almost specularly reflected.
This touch mark M is easily visible (if unevenness is formed on the surface due to the touch mark M, only that part will be diffusely reflected, and the touch mark M can be clearly seen), which will reduce its commercial value.

The present invention has been devised in view of the above-mentioned problems in the prior art, and it is possible to avoid defects in the rolls when the narrow lap seam weld passes through the dry temper mill and tension leveler in the continuous processing line mentioned above. The objective is to prevent touch marks from forming on bright finished materials, extend the life of these rolls, and enable stable operation.

[0007]

[Means for solving the problem] Therefore, the method of the present invention:
In a continuous processing line for bright finished materials equipped with a dry temper mill and a tension leveler, when the narrow lap seam weld of the bright finished material passes through the temper mill rolls, the sheet feeding to the temper mill is temporarily stopped immediately before the welded part passes through the temper mill roll. , the mill roll gap is opened to allow the sheet to pass through the welded part, the sheet threading is stopped again, and the mill roll gap is closed to restart the sheet threading to the tempering mill, and when the sheet threading is resumed, the sheet threading is performed at a low speed. Alternatively, the threading speed is reduced just before the weld passes through the tension leveler roll, and the intermesh of the tension leveler is lowered to the slip limit immediately before passing through the weld, and then the original threading speed is reduced. The basic feature is that it returns to board speed and intermesh.

[0008] The present inventors conducted a quick open test of the mill or intermesh in order to prevent touch marks that occur in dry temper mills and tension levelers, and the above structure of the present invention was devised based on the test results. It is what was done. Therefore, the test results will be explained below.

First, the results of a quick open test conducted using a dry temper mill will be explained. The drive type of this mill is usually a backup roll drive to facilitate roll rearrangement, so as shown in Figure 1, the speed at which the upper backup roll and upper work roll stop is proportional to the speed at which the rolls are opened. It takes a long time, and continuous annealing furnaces have drawbacks such as a large output looper capacity.

Next, the results of a quick open test of the intermesh in the tension leveler will be explained. If the tension leveler is applied again after this quick opening, the leveler roll is an idle roll, so there is a risk of roll scratches due to slipping, so in order to prevent this, the steel strip being threaded is stopped and the intermeshing Therefore, as mentioned above, in a continuous annealing furnace, there is a drawback that the outlet looper capacity becomes large.

On the other hand, apart from such a quick open test, the present inventors conducted an experiment to investigate how the various conditions of the dry temper mill and tension leveler affect the generation of touch marks. The following was discovered. That is, in a dry temper mill, as shown in FIG. 2, touch marks occur regardless of the load or speed of the mill. Furthermore, in the case of a tension leveler, as shown in FIG. 3, the degree of flaws that occur is affected by the intermesh of the tension leveler and the weld passage speed.

[0012] To summarize the above structure of the present invention derived from these experimental results, when the welded part of the bright finished material passes through a dry temper mill, the mill roll is completely opened from the finished material. , When re-contacting the mill rolls after passing, contact is made again with the sheet passing stopped to prevent roll scratches, and when the weld passes through the tension leveler, the amount of intermeshing and the speed at which the weld passes through the weld are determined. In some cases, it is possible to prevent touch marks from occurring even when the leveler roll is in contact with the finished material, so the speed during passing is reduced and the intermesh is also reduced to the slip limit before passing through the welded part. The idea is to do so.

[0013]

EXAMPLES Specific examples of the method of the present invention will be described below with reference to the accompanying drawings.

FIG. 4 shows an outline of the equipment of a continuous annealing furnace for TIN, in which the original TIN sheet X is rewound by a payoff reel 100, and a welder 101 performs narrow lap seam welding between the leading material and the trailing material. The sheet is continuously passed through the entrance looper 102, heating furnace 103, soaking furnace 104, gas jet cooling zone 105, first overaging furnace 106, second overaging furnace 107, quenching zone 108, and air cooling. The tension reel 11 on the exit side passes through the band 109, the exit looper 110, the 2-stand dry temper mill 1, the tension leveler 2, etc.
It will be wound into 1.

[0015] When the seam weld of the steel plate X passes through the dry temper mill 1 and the tension leveler 2 on the exit side of the furnace, the weld passage passing method of the present invention is carried out.
The method will be explained in detail below.

First, when the welded part comes in front of the dry tempering mill 1, as shown in FIG. 5, the line speed on the exit side is reduced, and just before the line is stopped, the welding part is placed in front of and behind the mill 1 as shown in FIG. 6(a). Anti-clipping roll ACR
12 and anti-cross brake roll ABR13 in the same figure (
As shown in b), the push-up cylinder 14 is also rapidly lowered at the same time (a lower work roll bender is used to further increase the lowering speed, and the lower work roll and backup roll are pushed down by the bender). , open the mill roll gap on both stands. The anti-clipping roll ACR12 and the anti-cross brake roll ABR13 are normally at a level 10 to 20 mm higher than the pass line, as shown in Figure 6(a), but during quick opening, they drop as shown in Figure 6(b). By tightening the mill roll gap, a pass line will be formed so that the mill roll gap does not have to be opened too wide. At this time, the mill roll gap is 2 mm above the steel plate
It will open 3mm downward, a total of 5mm. By the quick opening as described above, the elongation control (AEC) of the dry temper mill 1 is canceled as shown in FIG.
The tension of the mill 1 is controlled by the tension control of the mill 1.

With the mill roll gap as described above created, the welded portion is passed at low speed to the rear of both mill stands 10 and 11.

Thereafter, the exit line is stopped again, and the anti-clipping roll ACR12 and the anti-cross brake roll ABR13 are rapidly raised, as shown in FIG. 6(a).
At the same time, the mill stand 10 is restored to its original state.
The push-up cylinder 14 below 11 is also raised rapidly to bring the roll gap of the mill to zero. However, if the rising speed of the push-up cylinder 14 is too high, touch marks will occur due to the impact when the mill roll kisses the steel plate X. Therefore, as shown in FIG. During this period, the rising speed of the push-up cylinder 14 is set at 2 mm/sec, and when this gap becomes 1 mm, the rising speed is reduced to 0.5 mm/sec to soften the impact during roll kissing and prevent the occurrence of touch marks. That's what I do.

After this mill roll gap becomes 0,
As shown in FIG. 5, the sheet threading is resumed, but the sheet threading speed at this time does not return to the original sheet threading speed in accordance with the weld passage speed of the tension leveler 2, which will be described later.
The speed should be about 45mpm, which is slower than that.

Next, when the welded part is passed in front of the tension leveler 2 at a low speed of about 45 mpm, the elongation control of the tension leveler 2 is turned off, and instead of this, the tension bridles 31 and 32 arranged before and after the leveler are turned off. By controlling the tension of the tension leveler 2, the tension of the tension leveler 2 is controlled to be constant. At the same time, the intermesh of the tension leveler 2, which had been set to about 5 mm to 10 mm, was lowered to the slip limit of about 1 mm, as shown in FIG. 5. As shown in Figure 3 above, if the tension leveler passes through the weld at a relatively low speed of about 45 mpm or 90 mpm, setting the intermesh to about 1 mm will make it possible to touch even bright finished materials such as TIN original plates. No marks occur.

[0021] The welded portion is then passed through to the exit side of the tension leveler 2.

When this sheet threading is completed, as shown in FIG. 5, the tension control of the tension bridles 31 and 32 is returned to the elongation control of the tension leveler 2, and at the same time, the intermesh of the tension leveler 2 is returned to its original state. Bring it back. Then, when the welded portion enters the tension reel 111 and winding is completed, the original speed is returned to.

When the narrow lap seam weld of the TIN original sheet X was passed through the dry temper mill 1 and the tension leveler 2 as described above, no touch marks were printed on these work rolls due to the weld passing through the weld. Therefore, no touch marks were observed on the TIN original plate X. Furthermore, since touch marks are no longer printed on the work rolls, the life of each work roll of the dry temper mill 1 and the tension leveler 2 is extended.

[0024]

According to the welded part passing method of the present invention detailed above, when a narrow lap seam welded part of a bright finished material passes through a dry temper mill and a tension leveler, the welded part is formed on the surface of these work rolls. This eliminates scratches caused by pressing and prevents touch marks from being repeatedly printed on the surface of the bright finished material, improving product quality, extending the life of work rolls, and enabling stable operations. Become.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the speed at the time of roll opening in a dry temper mill and the time required for stopping the upper work roll and upper backup roll in response to this opening.

FIG. 2 is a graph showing the relationship between touch marks and passing speed and load when passing through a welded part in a dry temper mill.

FIG. 3 is a graph showing the passing speed of a tension leveler when passing through a welded portion, and the relationship between an intermesh and a touch mark.

FIG. 4 is an explanatory diagram showing an outline of the equipment of a continuous annealing furnace for TIN original plates to which the method of the present invention is applied.

FIG. 5 is a process explanatory diagram showing an example of control of sheet passing speed, mill roll gap, and intermesh control when passing through a welding zone in a dry temper mill and a tension leveler.

FIG. 6 is an explanatory diagram showing a specific example of mill roll gap control when passing through a welded part in a dry temper mill.

FIG. 7 is a graph showing a method of speed control of a push-up cylinder during mill roll gap closing control of a dry temper mill.

FIG. 8 is an explanatory diagram showing the mechanism of touch mark generation when passing through a welded portion.

[Explanation of symbols]

1 Dry temper mill 2 Tension leveler 10, 11 Mill stand 12 Anti-clipping roll 13
Anti-cross brake roll 14 Push-up cylinder X original plate

Claims (1)

[Claims] Claim 1: In a continuous processing line for bright finished materials equipped with a dry temper mill and a tension leveler, when the narrow lap seam weld of the finished material passes through the temper mill rolls, the material is passed through the temper mill immediately before passing through the temper mill rolls. After stopping once, the mill roll gap is opened to allow the sheet to pass through the welded part, and the sheet threading is stopped again.The mill roll gap is closed to resume sheet passing to the tempering mill. The welding section is carried out at a low speed, or the threading speed is reduced immediately before the welding section passes through the tension leveler roll, and the intermesh of the tension leveler is lowered to the slip limit immediately before passing through the welding section, A method for passing a bright finished material through a welded part of an in-line mill and tension leveler for a continuous processing line, characterized in that the original threading speed and intermesh are restored.