JPS60111711A - Control device of transportation in hot continuous strip mill - Google Patents

Abstract

PURPOSE:To rationalize operation by transporting the latter half material cut by crop shear at a prescribed retardation speed without once stopping the transport ation before introducing the material to a finishing mill by accelerating it to the inlet-side speed of the mill again. CONSTITUTION:In performing the designed dividing rolling of a rolling material by installing a delay table and a crop shear between a roughing mill and a finishing mill, the transportation of material is controlled, so that the latter half of material is transported by retarding it to a prescribed retardation transporting speed without once stopping the transportation before introducing it to the finishing mill by accelerating its speed to the inlet-side speed of finishing mill. Further, the retardation transporting speed is decided, by estimating the transporting loci of the tail end of the former half material and the front end of the latter half material in the process of the finishing mill and succeeding ones and calculating so that the gap time of the leading stand of finishing mill is minimum. In this way, the material transportation is performed by bringing the latter half material closer to the preceding material till the allowable limit of the restriction in installation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conveyance control device on the finishing input side of the latter half material during planned split rolling in a continuous hot strip rolling line.

The first example shows a typical arrangement of a conventional hot continuous strip steel rolling line.
As shown in the figure. In FIG. 1, the material heated in a heating furnace 1 is rolled to a predetermined thickness in a rough rolling mill 2 and conveyed to a delay table 3. In synchronization with the speed of the material being conveyed, the so-called cropped portions at the leading and tail ends of the material are cut off by the crop shear 4, and then rolled by the finishing mill 5 to the desired finished product thickness and then rolled by the hot run table 6. It is transported and wound up with a coil rough. 8.9 are finishing inlet and outlet thermometers, respectively.

Now, in hot rolling, it is necessary to achieve dimensional specifications such as the target finish exit plate thickness (finished product thickness), and at the same time, the rolling end temperature (finish exit temperature) must be within a predetermined temperature range due to metal engineering requirements. There is a need.

In order to satisfy this temperature condition, conventionally, for example, the finishing inlet temperature (FET) is measured with a thermometer 8, and the required finishing outlet temperature (
If it is predicted that the target temperature on the finish exit side (FDT) will be higher than the finishing pass schedule, oscillation control is performed to cool down the temperature by placing oscillation on standby on the finishing input side. However, if the temperature tends to be lower than FDT, the temperature of the material is controlled by increasing the extraction temperature on the heating furnace 1 side.

In recent years, the continuous casting ratio of slabs has increased and there has been a significant trend toward consolidation of slab sizes.In order to shorten the rolling pitch and improve yield, rough rolling mills are rolled as a single material and finishing rolling is Increasingly, so-called planned split rolling is being carried out, in which the material is cut into multiple pieces by a crop shear on the input side of the machine, and each divided piece is sequentially rolled in a finishing mill and coiled on different lines. At this time, the product sizes of the divided first half material and second half material may be the same or different.

Conventionally, the second half of the cut material during scheduled split rolling is once reversed to a predetermined position before the cropper, where it waits for oscillation to repeatedly move forward and backward, allowing an appropriate amount of time between it and the first half of the material that preceded it. After that, it was put into the finishing mill.

However, in recent years, energy saving has become the most important issue in hot rolling, and there has been a noticeable trend to lower the heating furnace extraction temperature as much as possible, and there are increasing cases where the temperature of the latter half of the material cannot be maintained with the conventional conveyance pattern. In other words, in the conventional method, the second half of the material returns to a predetermined position after cutting and then enters the finishing rolling mill again, so the transportation time is long, and especially when the target product thickness of the second half of the material is thin, the temperature of the second half of the material may be low. In many cases, it became difficult to secure the specified FDT due to cooling.Therefore, there were constraints on the finishing pass schedule for the second half of the material, and at the same time, there were also constraints such as not being able to reduce the finished thickness of the second half of the material very much. .

Therefore, the present invention was made to improve the conveyance pattern of the second half material during planned division rolling and to remove the above-mentioned conventional restrictions.The purpose of the present invention is to minimize the temperature drop of the second half material after planned division rolling. A technology that controls the conveyance of the material so that it approaches the preceding material as quickly as possible due to equipment constraints such as post-processing and beating lines, without having to retreat the material in order to guide it to the finishing mill as quickly as possible. The goal is to provide the following.

The present invention will be explained below with reference to the drawings. FIG. 2 is a configuration diagram of a hot continuous steel strip rolling line to which the conveyance control device of the present invention is applied. The rolling line shown in Fig. 2 is almost the same in configuration as the conventional hot continuous strip rolling line shown in Fig. 1, but the difference from Fig. 1 is that the rough rolling delay table B is As shown by diagonal lines in one section, a heating device 10 is installed to prevent the temperature of the material from decreasing or to increase its temperature.

The conveyance control device for rolling material constructed in this manner and applied to a continuous hot strip rolling line will be explained with reference to FIGS. 3 to 5. In order to achieve the above object, the present invention uses a pass schedule for the first half material and the second half material after planned division, so that the second half material does not collide with the first half material before the tail end of the first half wraps around the line. Calculate the conveyance speed (hereinafter referred to as VFSB) from to entering the finishing rolling mill.

FIG. 3 is a millbasing diagram showing the moving distance of the above-mentioned first half material and second half material over time.

The horizontal axis is the actual length of the line, and the vertical axis is time. Here C
8 is a crop mill, Fl to F6 are finishing mills, C
1 and C2 each indicate the arrangement of lines. 11.12
The solid lines in 16.14 indicate the trajectories of the tip and tail of the first half of the material passing through each piece of equipment, and the broken lines in 16.14 indicate the trajectories of the tip and tail of the second half of the material, which are calculated predictively from the rolling pass schedule. Therefore, in order to avoid interference between the first half material and the second half material from this trajectory, it is possible to set the delay table conveyance speed VFSB on the finishing entry side such that the curves of trajectories 12 and 13 do not touch.

Next, the second half of the material is transported by the VFSB charged by the above method, and the predicted finish exit temperature (FDTo) after finish rolling.
A check is made to see if the FDT falls within the allowable range of a predetermined FDT.

FIG. 3 shows a temperature curve of a rolled material during typical finish rolling. If the FIT, plate thickness, and finishing pass schedule of the rolled material are determined from this temperature curve, FDTo can be predicted using a temperature model equation.

As a result of the check, if FDTo is within the allowable range of the required FDT, after the planned division, the second half of the material is decelerated to VFSB and conveyed to the finishing mill 5.Furthermore, even with the above method, FDT cannot be obtained. If this is not possible, modify the finishing pass schedule to increase the thickness, issue VFSB again, and repeat the FDT check.

From the perspective of preventing the temperature drop of the second half of the material, the VFSB that minimizes the idle time on the finishing side is calculated, and the VFS
Using B, the predicted finish exit temperature of the second half material (hereinafter referred to as FDT
o) is calculated. If this FDTo falls within the range of the target finishing temperature, the second half of the material is conveyed to the finishing rolling mill 5 at that VFSB, but if FDTo exceeds the upper limit of the target temperature FDT, VFSB is decreased by a predetermined amount and VF8B
By calculating FD'r0 again as ', VF8B' that satisfies the temperature conditions and minimizes the rolling pitch is determined.

However, when the finished product thickness of the second half material becomes thicker than that of the first half material, the VFS of the second half material is increased in order to increase the temperature drop.
Although it is necessary to make B very small, VFSB has a minimum value VFSB, min from the viewpoint of preventing desk marks.

Therefore, even if VFSB < VFSB, min, if FDTo exceeds the upper limit of the outlet temperature, select a conveyance pattern in which the rolled material is once returned to a predetermined position on the finishing input side, and perform oscillation control. gives the desired result.

The above-mentioned transport control device according to an embodiment of the present invention will be explained using the flowchart shown in FIG. Up to this point, we have described the method that should be applied to prevent the temperature drop of the second half of the split material as much as possible, but depending on the relationship of the rolling pass schedule between the first half and the second half of the material, more specifically When the thickness of the finished product is thicker than that of the first half, there are cases where it is necessary to lower the temperature of the second half, contrary to the previous description. In this case, after cutting the second half of the material with crop shear 4,
It is sufficient to transport the material back to a predetermined position on the entry side of the finishing rolling mill 50 and wait for oscillation at the predetermined position for a time necessary to obtain a predetermined exit temperature, and the accompanying conveyance control device is conventionally known.

The next object of the present invention is to develop a mechanism for selecting an optimal conveyance method to expand the range of production of the second half of the raw material by selectively applying the two types of fc conveying devices for raw material after division according to the rolling schedule trap. It is about providing.

When the rolling schedules for the first half and the second half of the material to be divided are given, first the rolling pitch is minimized, and in Fig. A calculation block 16 calculates the running trajectory after the finishing rolling mill at the tip and tail end, and calculates a VFSB that avoids interference between the two and minimizes the idle time on the finishing input side. Inlet temperature FB
Finishing exit temperature FD from the rolling schedule of T and second half material
A computation block 17 predicts T0, and a comparison block 17 compares this FDTo with the target finishing temperature FDT'. F
If D'rC is within a predetermined range with respect to FDT,
Block 22 is selected.

When FDTC exceeds the upper limit width of FDT'', VFSB is lowered by a predetermined amount by calculation block 19 at the expense of rolling pitch and converted to VFSB', and comparison block 2
If the 00 judgment condition is satisfied, the calculation block 16 calculates #)FDTo again to determine ■FSB''.

If F'DT0 cannot be sufficiently lowered unless the relationship is VFSB (VFSB, min), it will be determined by the comparison block 20, and the output will be controlled so that the latter material is sent back to the finishing input side and is on standby for oscillation. The device 26 is selected.Also, the comparison block 18 shows that even if the temperature of the second half of the material decreases significantly and VFSB is selected, which minimizes the finishing inlet pitch, the finishing exit temperature of the second half of the material FDT0 is the lower limit of "FDT". This is the calculation block 21 for the case where the value is less than VFS.
It is conveyed and rolled at speed B, and the method thereof is conventionally known.

As described above, conveyance #-11 of the hot continuous strip rolling mill of the present invention
1kn jd= HA +y hi, h l, F force
M + li yz JF -x tongue↓TE=l:! y
As a conveyance device for the second half material in the second half of the process, it is possible to minimize the idle time on the finishing input side and determine the conveyance control to minimize the temperature drop for rolled materials where temperature drop is a problem. For materials that require a large temperature drop, the oscillation pattern before the finishing mill can be automatically selected, which expands the selection range of rolling schedules for the latter half of planned split rolling, greatly contributing to streamlining operations. Since the temperature drop of the second half material can be minimized, it is also effective in terms of energy saving.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional hot continuous zone conditioning rolling mill, FIG. 2 is a schematic configuration diagram of a hot continuous zone conditioning rolling mill to which a conveyance control device according to an embodiment of the present invention is applied. Figure 3 shows the millbasing diagram of the first and second half of the rolling mill shown in Figure 2.
Fig. 4 shows a temperature pattern diagram of the rolled material in the rolling mill shown in Fig. 2, and Fig. 5 shows the determination of the post-posting transport pattern by the transport control device of the hot continuous zone rolling mill according to an embodiment of the present invention. It is a flow diagram. DESCRIPTION OF SYMBOLS 1... Heating furnace, 2... Rough rolling mill, 8 river day table, 4... Crop shear, 5... Finishing rolling mill, 6... Hot line table, 710. Line, 8.9... Thermometer, 10... Heating device, 15
゜16.19.21...Arithmetic block, 17,18゜20...Comparison block, 22.28...Output block. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa

Claims (2)

[Claims] (1) A delay table for conveying the rolled material between a rough rolling mill and a finishing rolling mill and a crop shear for cutting the rolled material into first half material and second half material are installed to control the conveyance of the above rolled material. In the conveyance control device of the strip rolling mill,
When controlling the conveyance of the second half of the material cut by the crop shear, the second half of the material is decelerated to a predetermined deceleration conveyance speed without stopping, and then the speed is increased again to the entry speed of the finishing mill. 1. A conveyance control device for a continuous hot strip rolling mill, characterized in that the conveyance is controlled so as to be quickly introduced into the finishing rolling mill. (2) The predetermined deceleration conveyance speed of the second half material is determined by predicting the conveyance locus of the process after the finishing mill at the tail end of the first half material and the tip of the second half material, and 2. The conveyance control device for a hot continuous zone conditioning rolling mill according to claim 1, wherein the device calculates and determines the gap time to be the minimum time.