JPS6051968B2 - How to trim steel strip - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for trimming steel strip.

In the manufacturing process of steel strip, such as hot rolling and cold rolling, trimming is performed to ensure the product width accuracy of the steel strip.

By the way, in this trim, in order to prevent the band-shaped scrap cut off from the steel strip from scattering around, it is necessary to dispose of it in an appropriate manner, and the conventional disposal methods such as choppers and borers have been widely used. . However, with this type of processing method, if the scraps are sent intermittently with a break in the middle, the leading ends of the scraps may get caught in the processing equipment, resulting in so-called "ear trapping", which makes processing virtually impossible. Once such trouble occurs, the line is forced to stop in almost all cases. In order to avoid such problems to some extent, it is possible to cut out scraps in a continuous manner rather than intermittently, but in order to do so, it is necessary to cut out scraps in a continuous manner rather than intermittently. However, it is necessary to take a fairly wide trim allowance, and a significant drop in yield is unavoidable. In reality, in order to avoid such a significant drop in yield, trimming is performed with a small trimming allowance, but in this case, the line may have to be stopped more than 100 times due to the above-mentioned ear hooks. This is the biggest cause of lower line operating rates. In addition, if the line has pickling equipment attached to it, such line stoppages can cause problems such as over-pickling of the steel strip, which can cause problems not only in the operating rate but also in the quality of the steel strip. This also includes the problem of causing problems. The present invention was created to solve these conventional problems.
It is an object of the present invention to provide a trimming method that does not reduce the yield of steel strip and does not cause troubles such as line stoppages by appropriately carrying out scrap processing.

For this reason, the present invention minimizes the yield loss by performing minimal trimming only on the portions that require trimming in the longitudinal direction of the steel strip, and scraps that are intermittently generated due to such trimming.・By applying a certain amount of processing at almost the same time as trimming, it is possible to prevent problems such as ear catching in the processing equipment, thereby preventing situations such as line stoppages. . The basic feature for this purpose is to perform trimming only on the part of the steel strip that is wider than the preset steel strip width,
In addition, such partial trimming is performed by making notches at predetermined intervals in the longitudinal direction of the scrap, and in this way, the yield can be maintained at a high level and the scrap can be If the material is sent to the scrap processing equipment in a state in which its rigidity has been reduced so that it can easily break from each notch, and as a result, if the end portions become caught in the scrap processing equipment, causing the edges to catch. However, due to the impact at this time, it is easily broken from the notch portion and becomes small scrap chop waste, which appropriately prevents the occurrence of ear catching troubles in the processing equipment. The details of the present invention will be explained below.
The present invention performs minimal trimming only in the portions where trimming in the longitudinal direction of the copper strip is necessary. For this reason, partial trimming is performed only in portions of the steel strip that are wider than a preset width of the copper strip. conduct.

As mentioned above, in the past, in order to ensure the continuity of scrap, trimming was performed with a trimming margin that exceeded the required precision of the product. For example, in the case of cold-rolled copper sheets, the trimming margin was approximately 5 to 7.5 Tfrm on one side. Even though I had to pay a certain amount of trim fee. On the other hand, in the present invention, it is possible to perform trimming only based on the required precision of the product, and therefore, a target width of the strip is set, and trimming is performed only on the portion that exceeds the target width. This target width is generally [specified width + α]! is set to [Strip Width]
〉[Specified width + α] Only when that part is trimmed. Here, 0×α is the allowable tolerance, specifically,
If no separate trim is performed at the final stage, the product tolerance is 0. It is assumed that α is the plate thickness x (1.0 to 3.0). Further, particularly in the case of hot rolled steel strip, irregularities in strip width are concentrated at the front and rear ends of the steel strip, and normally the steady rolling portion has a substantially constant width.
Therefore, in the case of such a hot rolled steel strip, the target strip width is set such that only the wide portions at the leading and trailing ends described above are trimmed. The above is the basic configuration of the present invention, but if the width accuracy of the steel strip is extremely high and it is extremely close to the width set by the trimming device, the frequency of partial trimming will be extremely high, making it meaningless from an industrial perspective. Partial trimming with extremely small trimming allowances (for example, 0.1?) is repeated frequently, which shortens the life of the trimming device knife.

In order to avoid such a situation, the width of the steel strip is continuously measured, and by this measurement, parts of the copper strip that are wider than the preset steel strip width are detected, and only the parts of the copper strip that are wider than the preset steel strip width are detected. Preferably, trimming is performed. FIG. 1 shows a trimmer control system for performing such trim, in which 1 is a strip width measuring device, 2 is an arithmetic unit, 73 is a steel strip target setting device, and 4 is a trimmer control device. According to this control system, the width of the steel strip is continuously measured by the strip width measuring device 1, and the arithmetic unit 2
The measured width is compared with the target width, and if the measured width>target width, a trimming command is issued to the trimmer control device 4. The trimmer 5 is moved in the direction of the steel strip 6 by the trimmer control device 4, and trimming is performed only on the portion exceeding the target width. It is sufficient that this trim is performed in a form that satisfies the required precision of the product, and therefore, portions with small width irregularities may be excluded from the trimming target. In this case, processing such as passing the detection signal through a low-pass filter is performed.
As for the scraps that are intermittently generated due to the partial trimming as described above, notches are made at predetermined intervals in the longitudinal direction of the scraps, and then the scraps are sent to the scrap processing device.

FIG. 2 shows such a trim situation. Reference numerals 7 and 8 denote an upper cutter and a lower cutter that constitute the trimmer, and almost simultaneously with trimming by the upper and lower cutters, notches 10 are sequentially put into the scrap 61 by a notch 9 attached to the lower cutter 8, and the notches 10 are sequentially inserted into the scrap 61. Scrap processing equipment (
(not shown).

The formation of the notches 10 is such that it reduces the rigidity of the scrap 61, so that the scrap 61 can easily break at the notch portion 10 due to a certain impact. state. Notch 10 above
. . is preferably formed at a depth of approximately 60% or more of the thickness of the scrap board in order to reduce the rigidity of the scrap. Then, in this way, the notches 10 and 10 are made at intervals.
The scrap 61 with the... formed thereon is processed by the scrap processing device from which it was sent out, but even if the end gets caught in the device, the impact at that time will cause the notch 10 ... easily breaks into small pieces, preventing trouble from getting stuck in the processing equipment. In this way, with the method of the present invention, it is possible to perform trimming based only on the required accuracy of the steel strip, so it is possible to reduce the trim loss rate to about 90 to 95% compared to the conventional method, and as a result, the trimmer The life of the blade can also be significantly extended.

The method of the present invention is applied to the finishing process of cold rolling lines and hot rolling lines, as well as trimming at the entry and exit sides of Zn plating lines, but when trimming is performed twice, such as with tin-plated steel sheets, the required accuracy is It can be said that this is particularly useful for the first trim which is not very severe. According to the present invention described above, the trimming cost can be significantly reduced compared to the conventional method, and scrap processing using such trimming can be carried out appropriately, so that the steel strip yield can be improved and line stoppages, etc. can be avoided. Appropriate line operation can be ensured without causing any trouble.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram of a trimmer control system used for carrying out the present invention, and FIG. 2 is an explanatory diagram showing trim conditions in the method of the present invention. In the figure, 5 is a trimmer, 6 is a steel strip, 9 is a notcher, 10 is a notch, and 61 is a scrap.

Claims (1)

[Claims] 1. Trimming is performed only on a steel strip portion wider than a preset steel strip width, and the partial trim is performed by notching the resulting scrap at predetermined intervals in its longitudinal direction. A method for trimming a steel strip, characterized in that the trimming method is performed while 2. A patent characterized in that the width of the steel strip is continuously measured, a steel strip portion wider than a preset steel strip width is detected by the measurement, and trimming is performed only on the steel strip portion. A method for trimming a steel strip according to claim 1.