JPS6156718A - Plate width controlling method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a strip width control method in a hot strip mill comprising a roughing mill group and a finishing mill group.

[Conventional technology]

Generally, a hot strip mill has a configuration in which a rough rolling mill group A and a finishing rolling mill group B are installed in series, as shown in FIG. Among them, rough rolling mill group A is used for sheet thicknesses of 150 to 300 mm extracted from heating furnace I, and plates @700 to 180 mm.
0 +n, the rolled material 2 with a plate length of 4 to 10 m is subjected to width reduction and thickness reduction using vertical rolling mills El to E6 and horizontal rolling mills R1 to R6, and the plate thickness of the rolled material is reduced to 30 to 50 fi and the plate width. Rough rolling is carried out with a length of 700 to 1800 m and a plate length of 50 to 90 m. The rolled material 2 that has come out of this rough rolling mill group A is cut off at the next crop shear 3 to have the unnecessary loaf portions at the leading and trailing ends cut off, and is then processed to the finishing rolling mill group B, which consists of a plurality of horizontal rolling mills taF+ to F7, as needed. The plate is finish rolled to 1.2 to 2 (in.) and then wound up by the coiler 4.

In the hot strip (hot rolled steel strip) rolled in this manner, there are usually parts distributed over the entire length of the rolled material that have a width deviation of 5 to 3011 degrees.

Next, the cause of this sheet width deviation will be explained with reference to Figures (al and bl) in Figure 4. Fi width is shown with respect to the longitudinal direction position, and II (bl is the plate width with respect to the longitudinal direction of the rolled material measured at the exit side of finishing rolling mill group B. Also, in Figures (a) and (G)), the left wheel is the tip of the rolled material, and the right end is the rear end.In rough rolling mill group A, the addition qj,
%Igi l Width e in the intermediate part of the rolled material due to uneven baking due to skid marks etc. of the slab in the mill, and the leading and trailing ends due to vertical rolling and horizontal rolling (within 8 m at the exit length of the rough rolling mill ff1-A) Locally narrow widths d, f and wide widths c, g occur in the area).

Further, in finishing rolling mill group B, rolling is performed with tension applied to the rolled material in order to prevent meandering of the rolled material and loops between stands (sagging of the rolled material). It is a well-known fact that a width line is generally formed when tension is applied. However, the width line dose is small in the skid mark area because the temperature is low, and the width line dose is thick in other high temperature areas (as a result, the strip width deviation e' in the middle area due to the skid mark is It is more dogged than the plate width deviation e.Also, the leading and trailing edge of the rolled material (the part within 1 m on the exit side of the rough rolling mill group A)
In this case, there is no tension, no width line is generated, and the width is widened locally due to horizontal rolling at the leading and trailing edges.
/, g/ are generated.

There are the following two conventional techniques for eliminating the plate width deviation that occurs in this way. One of them is a strip width control method that controls the roll opening degree of the vertical rolling mill in rough rolling mill group A, and the other one is to change the tension between stands in finishing rolling mill group B.
This is a sheet width control method for controlling the width line of a rolled material. However, in the method of controlling the tension between the stands of finishing mill group B, it is difficult to apply tension to the leading and trailing ends of the rolled material, so the wide C'1g' that occurs at the leading and trailing ends of the rolled material is difficult to apply. It is impossible to eliminate the problem. Therefore, such a wide range
/, g/ can be solved by controlling the roll opening degree of the vertical rolling mill.

[Problem that the invention seeks to solve]

However, in conventional vertical rolling mill roll opening control, the maximum rolling speed is about 100 m/s, which limits the capacity of the rolling mill. Therefore, it has not been possible to eliminate the plate width deviation. That is, for example, the rolling speed of the final vertical rolling mill E6 to the rough rolling mill group is 4 m/s. Further, the length of the wide width e of the rolled material 2 is at most about 400 nm, and the rolling passage time of this portion in the final vertical rolling mill E6 is about 0.1 seconds. Moreover, the maximum control amount required here is 20 to 30 dragons. Therefore, if you try to eliminate the strip width deviation with the vertical rolling mill E6, it will take 200 to 300
A reduction rate of ioi/s is required. However,
The rolling speed of the conventional vertical rolling mill is < 1ofs as mentioned above.
/S is the limit, and it has not been possible to eliminate plate width deviation.

In addition, when strip width control is performed in any of the vertical rolling mills El to E5 in rough rolling mill group A, strip width deviation The amount of control required to eliminate this becomes extremely large and is practically uncontrollable.

In addition, the conventional strip width control method using roll opening control in rough rolling mill group A measures the strip width of the rolled material 2 at the entrance side of the vertical rolling mill, and sets the roll opening of the vertical rolling mill based on the measurement. ing. What is important here is the matching of each plate width measurement surface in the longitudinal direction of the rolled material and the control position of the roll opening degree. If an error occurs in this matching, not only will the control effect be lost, but the sheet width deviation will increase, which is not preferable. One of the conventional methods of matching the position of the rolled material is to measure the sheet width, then detect the tip of the rolled material using a hot total deflection detector (hereinafter referred to as HMD), and then match the tip of the rolled material using the speed of a table roller for squeezing the rolled material. The time required for the tip of the rolled material to reach the vertical rolling mill is predicted. Another matching method uses a rolled material biting signal from a load cell attached to the vertical rolling mill to detect that the leading end of the rolled material has reached the vertical rolling mill.

However, in these matching methods, the exact position of the rolled material cannot be determined by i =
33 was difficult.

In addition to this, the matching method using the load cell has the disadvantage that the matching error becomes large due to the lagging signal of the load cell.

In addition, in the rough rolling mill group A, water vapor is constantly generated by a descaler for removing scale from the rolled material and roll cooling water. Therefore, in the matching method using the HMD, highly accurate rolling phase position matching cannot be performed due to the influence of water vapor disturbance.

In short, in the conventional hot strip mill, which uses a strip width control method that controls the vertical rolling mill based on the roll opening degree, technology needs to be solved in terms of vertical rolling mill capacity (rolling speed) and position matching of the rolled material. Due to this problem, it was not possible to control the plate width with high precision.

Therefore, in the past, the above-mentioned plate width deviation was taken into account in 1.・
The target sheet width was set wide and the hot strip was rolled, and the extra width was then trimmed to produce the product.

Therefore, as the target board width is made wider, the yield is poorer, and an improvement has been desired. Naturally, this target plate width is widened to cover the entire length of the rolled material.
The effect on yield was very large.

c Means for Solving Problems] The present invention addresses the above-mentioned drawbacks of the conventional technology and improves and eliminates them. A vertical rolling mill and a crop shear are arranged close to each other between the finishing rolling mill group and the finishing rolling mill group,
Rolled material position detection devices are installed on the entry and exit sides of these vertical rolling mills and crop shears to detect the strip width of each surface in the longitudinal direction of the rolled material and the position of the rolled material measured with a width meter on the rough rolling mill group side. The roll opening degree of the vertical rolling mill is controlled based on the longitudinal position of the rolled material measured by the device, and the rolled material by the crop shear is controlled based on the longitudinal position of the rolled material measured by the rolled material position detection device. The purpose of this invention is to provide a method for controlling the width of a sheet by performing flop cutting at the leading and trailing ends, thereby achieving highly accurate sheet width control and excellent improvement in yield.

The method of the present invention will be explained in more detail below based on embodiments shown in the drawings. Note that the same reference numerals as in the conventional case represent the same members.

〔Example〕

FIG. 1 is a block diagram showing the arrangement of a hot strip mill to which the method of the present invention is applied.

As shown in the figure, in this embodiment, the vertical rolling tRE 7 and the crop shear 5 are moved to a position close to the finishing rolling mill group B between the rough rolling mill group A and the finishing rolling mill group B. They are arranged in order. A measuring roll 8 as a rolling material position detection device and an HMD are installed on the entrance side of the vertical rolling mill E7.
7 is installed.

The measuring roll 8 is for measuring the length of the rolled material 2, and the HMD 7 is for detecting the front and rear ends of the rolled material 2. Furthermore, a measuring roll 9 as a rolling material position detection device is also arranged on the exit side of the crop shear 5. 6 is a strip width measuring device provided on the exit side of the horizontal rolling mill R6 of the rough rolling mill group A.

Next, the reason why the vertical rolling mill E7 and the crop shear 5 are provided between the rough rolling mill group A and the finishing rolling mill group B will be explained. That is, the above-mentioned rough rolling mill group A and finishing rolling mill group B
In order to match the crop cutting speed of the crop shear 5 and the rolling speed of the finishing mill group B, the conveying speed is generally reduced to about 115 times lower than the rolling speed of the roughing mill group A.

Further, the rolled material 2 in this section has been sent to the rough rolling mill group, and has a sufficiently thin plate thickness. Therefore, in this section, the length of the part corresponding to the wide e' in Fig. 4 (bl) is approximately 500 to 600 FI11.
The rolling speed for vertically rolling the portion corresponding to ' may be slow, and the strip width can be controlled by controlling the roll opening at a rolling speed of 100 mm/s or less. In addition, the vertical rolling mill E7 is arranged independently and is not subject to the restrictions of the following rolling mills like the vertical rolling mills of the rough rolling mill group A mentioned above.
Enables sufficient board width control.

Additionally, measuring rolls 8 as rolling material position detection devices are installed on the input and exit sides of the vertical rolling RE 7 and the crop shear 5.
The reason why HMD 9 and HMD 7 are provided is as follows. That is, measuring roll 8 and HM are placed on the entrance side of vertical rolling mill E7.
D7 is provided because the position of the rolled material 2 cannot be accurately measured unless the position of the rolled material 2 is recognized before the tip of the rolled material 2 reaches the vertical rolling mill E7 or the crop shear 5. It is. Also, the reason why the measuring roll 9 is provided at the exit (II) of the crop shear 5 is that if the roll 9 were not present, the rolled material 2 would have passed through the measuring roll 8 and the HMD 7 on the input side. Vertical rolling RE7 from rear end
Alternatively, the position of the rolled material 2 up to the crop shear 5 cannot be detected.

In addition, in the rolling equipment of the example shown in FIG. 1, the interval between the rough rolling mill group A and the finishing rolling mill group B is 130 m,
The length is set to be considerably longer than the length of 90 m of the rolled material 2 after leaving the rough rolling mill group A. This means that in this section,
As mentioned above, this is to reduce the rolling speed of the rolled material 2 to about 115 compared to the rolling speed of the rough rolling mill group A. If the length is shorter than the length of Ffl on the outlet side of rough rolling mill group A,
A looping device may be provided between the width measuring device 6 and the measuring roll 8 on the entry side of the vertical rolling mill E7.

Next, a sheet width control method using the above-mentioned embodiment equipment will be explained.

First, the width of the rolled material 2 after leaving the final horizontal rolling tt'l R6 of the rough rolling mill group A is measured by the strip width measuring device 6 at a constant pinch over the entire length of the rolled material.

The measured value signal j is outputted to the board width storage device 10, stored therein, and outputted as a signal to the next calculation device 11. The calculation device 11 calculates the strip width deviation at each position in the longitudinal direction of the rolled material from the value of the signal and a predetermined target strip width on the exit side of the rough rolling mill group. Further, the calculation device 11 predicts and calculates the amount of widening at the leading and trailing edge of the rolled material that will occur in the next finishing mill group B based on the measured values.

On the other hand, in the input side rolled material position detection device, the rolled material 2
When the leading edge of the rolled material 2 is detected by the HMD 7, the measuring roll 8 starts measuring the longitudinal position of the rolled material 2.

The rolled material position storage device 12 receives the detection signal q of the HMD 7.
and the measurement signal p of the measuring roll 8 are stored and outputted to the arithmetic unit 11 as a signal r. The calculation device 11 matches the longitudinal position of the rolled material 2 in the vertical rolling mill E7 with the strip width measurement point based on this signal r and the signal of the strip width storage device 10 (rolled material position matching).
The installation location of the above HMD 7 and measuring roll 8 is as follows.
It is possible to obtain a highly accurate position detection signal without being affected by water vapor from the descaler or roll cooling water as in the case of the rough rolling mill group A.

The arithmetic device 11 determines the roll opening control amount based on the sheet width deviation obtained in the above-described manner and the predicted widening amount, and outputs this to the roll opening degree changing device 13 as a signal m. It is clear from the foregoing that this output signal m matches the longitudinal position of the rolled material 2 in the vertical rolling mill E7. The roll opening degree changing device 13 calculates a control amount (change amount) of the roll opening degree from the signal m and the current roll opening degree of the vertical rolling mill E7, and outputs this as a signal n to the vertical rolling mill E7. . Thereby, vertical rolling is performed in order to correct the plate width deviation and the predicted widening amount of the rolled material 2.

After the rolled material 2 leaves the vertical rolling mill E7, the next crop shear 5 cuts off the flop portion at the tip. After the tip of the rolled material after cutting [r] is bitten by the horizontal rolling mill Fl of the finishing rolling mill group B, the measuring roll 9 installed on the exit side of the crop shear 5 is moved to cut the rolled material. 2 is detected in the longitudinal direction. This detection signal t is stored in the rolled material position storage device 14. The position detection signal t by the measuring roll 9 can also be detected with high precision for the same reason as the reason for installing the HMD 7 and the measuring roll 8. After the rear end of the rolled material 2 passes through the measuring roll 8 on the entry side of the vertical rolling mill E7, the information is transferred from the rolled material position storage device 12 to the rolled material position storage device 14.
The position signal V of the rolled material 2 is output from the device 14 to the arithmetic device 11. The computing device 11 performs the same rolling material position matching as described above based on the signal V, and controls the roll opening degree of the vertical rolling mill E7 depending on the entire length of the rolling material 2.

Finally, the cropped portion at the rear end of the rolled material 2 is cut with a crop shear 5.

Thereby, excellent control of the width of the rolled material 2 is possible.

Figure +8) in Figure 2) and (in the figure) show the results of an experiment in which a slab with a thickness of 270u, width of 1250m, and length of 10m was rolled in order to prove the effect of strip width control using the above-mentioned example equipment. FIG. II (al
shows the plate width α of the rolled material 2 after leaving the rough rolling mill group and the roll opening degree β of the vertical rolling mill E7. Also, the figure (incorrect) shows the width of the rolled material 2 after leaving the finishing mill group B. 1 (al and figure ('b)
, the left end is the leading end of the rolled material 2, and the right end is the rear end.

It is clear from FIG. Control is being carried out to narrow it down. Further, in the longitudinally intermediate portion of the rolled material 2, roll opening degree control is performed to eliminate sheet width deviation due to uneven burning such as skid marks. Furthermore, at the rearmost end of the rolled material 2, control is performed to narrow the roll opening in order to eliminate the predicted widening, similar to the case at the leading end. As a result, as shown in Figure (b+), the width of the rolled material 2 after leaving finishing mill group B fluctuates within ±l wm over its entire length. A yield improvement of 0.3% was obtained.From these results, it is clear how superior the sheet width control method of the present invention is.

Note that the strip width control method of the present invention is not limited to the above-mentioned embodiments (appropriate changes are possible). For example, the vertical rolling mill E7 may be disposed downstream of the crop shear 5. Also, the crop shear 5, the measuring rolls 8 and 9 as the rolling stock position i detection device, and the HMD 7 are
It may be an existing one.

〔Effect of the invention〕

As explained above, in the present invention, the longitudinal failure surface of the rolled material is detected in the section where the conveyance speed of the rolled material is about 115 times slower than the rolling speed of the rough rolling mill, and the relationship between the rolling material and the plate width is determined. Matching is being performed. However, this section is not affected by descaling or water vapor from roll cooling water, so
Accurate position matching is possible. In addition, in the above section, the thickness of the rolled material is at the center, and the length of the width deviation part that occurs due to uneven burning such as skid marks is also sufficiently long, so the rolling speed of the vertical rolling mill is required to correct this. It is sufficient that the equipment is of the same level as the existing equipment. In addition, since the vertical rolling mill installed in this section is independent, it is not restricted by the following vertical rolling mills like the vertical rolling mills in the rough rolling mill group, and sufficient strip width control can be performed.

Therefore, with the strip width control method of the present invention, highly accurate strip width control can be performed and a dramatic improvement in yield can be realized.

[Brief explanation of drawings]

Figures 1 and 2 are related to the present invention; Figure 1 is a block diagram of the example equipment, Figure 2 is a drawing showing actual control results and control status, and Figures 3 and 4 are This is related to the prior art, and FIG. FIG. 4 is a drawing showing the entire equipment of the strip mill, and is a drawing showing the strip width with respect to the longitudinal position of the rolled material after leaving the rough rolling mill group and after leaving the finishing rolling mill group. A... - Rough rolling mill group B... Finishing rolling mill group E7.
...Vertical rolling mill 5...Crop shear 2...Rolled material 7...HMD8.9...Measuring roll Patent applicant Sumitomo Metal Industries Co., Ltd. Agent
Patent Attorney Toshihiko Uchida 2nd (a) Nokoji Mimi 1442 terrorist attack 5) Ihl Sagi. (b) /i 4 years old, long side 10 feet, @

Claims (1)

[Claims] 1. In a hot strip mill consisting of a rough rolling mill group and a finishing rolling mill group, a vertical rolling mill and a crop shear are placed close to each other between the rough rolling mill group and the finishing rolling mill group, and these vertical rolling mills and Rolled material position detection devices are installed on the entry and exit sides of the crop shear, and the plate width at each position in the longitudinal direction of the rolled material is measured with a width meter on the exit side of the rough rolling mill group, and the rolling width measured with the rolled material position detection device. The roll opening degree of the vertical rolling mill is controlled based on the position in the longitudinal direction of the material, and the front and rear ends of the rolled material are controlled by the crop shear based on the longitudinal position of the rolled material measured by the rolled material position detection device. A board width control method characterized by performing crop cutting.