JP2005305500A - Method for deciding rolling order of slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deciding method of the rolling order of slabs by which the total rolling time of rough rolling is shortened. <P>SOLUTION: This method is a deciding method of the rolling order of the slabs including a plurality of controlled rolled-stocks to which finish rolling is applied after rough rolling and cooling them and which has a stage where a plurality of combination patterns for making the slabs into a pair of every two consisting of a preceding material and a succeeding material are prepared, a stage wherein tandem rolling is made possible in the case the cooling time of the preceding material is beyond the rough rolling time of the succeeding material and the tandem rolling is disapproved in the case deviating from this condition, a stage wherein the total rolling time from the start of the rough rolling of the preceding material to the completion of the finish rolling of the succeeding material is calculated in the case the tandem rolling is possible and a stage wherein the total rolling time of the preceding material and the succeeding material is calculated in the case the tandem rolling is disapproved. the rolling is performed by selecting the combination pattern the total rolling time of which is smallest after similarly processing by changing the order of the preceding material and the succeeding material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for determining the rolling order of slabs including a plurality of controlled rolled materials that are subjected to finish rolling after rough rolling and cooling.

In recent years, control rolling (Controlled Rolling) has been adopted in which rolling of a thick steel plate having a thickness of, for example, 6 mm or more from a slab is performed after rough rolling and cooling and then finishing rolling. Various proposals have been made for this controlled rolling method.
For example, in Japanese Patent Laid-Open No. 59-61504, a cooling zone is provided outside the rolling line, and when waiting for the temperature of the steel sheet, cooling is performed there, and effective use of the rolling line is required. A method for improving the efficiency of a steel sheet having a low rolling efficiency is disclosed.
Japanese Laid-Open Patent Publication No. 60-180604 discloses a cooling bed that can be transported from the rolling line to the rolling material transport line between the rolling line and the rolling material transport line, and transported from the rolling material transport line to the rolling line. There is disclosed a method of providing a possible cooling bed, air-cooling a rolled intermediate thickness rolled material to a predetermined temperature in the cooling bed and the rolled material conveyance line, and then returning to the rolling line and rolling to a predetermined finished thickness. .
However, the methods disclosed in Japanese Patent Application Laid-Open Nos. 59-61504 and 60-180604 require a new cooling zone, resulting in an enormous amount of capital investment and the advance materials. The total rolling time of the preceding material and the following material can be shortened by performing rough rolling of the following material while cooling the material, and performing finish rolling of the preceding material while cooling the following material. Even when tandem rolling is performed, optimal (shortest time) tandem rolling cannot always be realized.
JP 59-61504 A JP 60-180604 A

  The present invention solves the problems of the prior art as described above, and performs rough rolling of the subsequent material while the preceding material is cooled, and finish rolling of the preceding material while the subsequent material is being cooled. It is an object of the present invention to provide a method for determining the rolling order of slabs that can shorten the total rolling time of the preceding material and the succeeding material in tandem rolling.

The present invention has been made as a result of intensive studies in order to solve the above-mentioned problems, and performs rough rolling of the succeeding material while the preceding material is being cooled, and while the succeeding material is being cooled. The present invention provides a slab rolling order determination method capable of shortening the total rolling time by devising a combination pattern of a preceding material and a succeeding material in tandem rolling that performs finish rolling of a preceding material. However, the following contents are as described in the claims.
(1) A method for determining the rolling order of slabs including a plurality of controlled rolled materials that are subjected to finish rolling after rough rolling and cooling,
A step of creating a plurality of combination patterns in which the slab is paired every two of the preceding material and the following material;
When the time for cooling the preceding material exceeds the rough rolling time of the succeeding material and the cooling time of the following material exceeds the finish rolling time of the preceding material, tandem rolling is possible, and this condition is not satisfied. The process of making tandem rolling impossible,
In the case where the tandem rolling is possible, a step of calculating a total rolling time from the rough rolling start of the preceding material to the finish rolling finish of the succeeding material;
In the case where the tandem rolling is impossible, a step of calculating a total rolling time of the preceding material and the following material,
A method for determining the rolling order of a slab, wherein the same processing is performed by changing the order of the preceding material and the succeeding material, and the combination pattern having the smallest total rolling time is selected and rolled.
(2) When the controlled rolling material is an odd number, one slab that has not been paired is calculated for the rolling time and added to the total rolling time. Rolling of the slab according to (1) Order determination method.

According to the present invention, the preceding material and the succeeding material in tandem rolling in which the subsequent material is roughly rolled while the preceding material is cooled and the preceding material is finish-rolled while the succeeding material is cooled. It is industrially useful, such as providing a method for determining the rolling order of slabs that can reduce the total rolling time by calculating the total rolling time for each combination pattern and selecting and rolling the optimal combination pattern There is a remarkable effect.

The best mode for carrying out the invention will be described in detail with reference to FIGS.
FIG. 1 is a diagram showing a rolling procedure of tandem rolling used in the present invention.
In FIG. 1, first, the preceding material a is caught in the rolling mill and then roughly rolled for the time to wait for cooling (t1a), and the temperature waiting time (t2a) required to reach the target temperature by air cooling. Only after cooling and finish rolling for the rolling time (t3a) after waiting for the temperature.
Similarly, after the trailing material b is caught in the rolling mill, it is roughly rolled for the time to wait for cooling (t1b) and cooled by the temperature waiting time (t2b) necessary to reach the target temperature by air cooling. Then, finish rolling is performed for the rolling time (t3b) after waiting for the temperature.

同様に、スラブ本数ｎ＝６の場合、２本ずつ３組のペアの組み合わせパターンは、表１に示す１５パターンあり、この場合は単独のスラブは存在しない。

本発明者等はこの組み合わせパターンと合計圧延時間との関係について検討したところ、このタンデム圧延を行う場合のペアの組み合わせパターンおよび各ペアの圧延順序によって合計圧延時間が変化することを見出し、最適な組み合わせパターンを選択することによって合計圧延時間短縮することができるスラブの圧延順番決定方法を完成させた。 As shown in FIG. 1, in tandem rolling, the subsequent material b is roughly rolled while the preceding material a is being cooled, and the preceding material a is finish-rolled while the subsequent material b is being cooled. By doing so, the total rolling time of the preceding material a and the succeeding material b can be shortened.
For slabs containing multiple controlled rolled materials, rough rolling of the following material is performed while the preceding material is being cooled, and tandem rolling is performed to perform finish rolling of the preceding material while the following material is being cooled. In this case, there are a plurality of combination patterns of slab pairs, and there are combination patterns that can be calculated by the following equation (A).
Combination pattern = (n-1) (n-3) (n-5) ... 3 (A)
Where n is the number of slabs (n ≧ 4)
For example, when the number of slabs n = 5, there are 12 pairs of combinations of two pairs each shown in Table 1. Since n is an odd number, one single slab remains.

Similarly, when the number of slabs n = 6, there are 15 combinations shown in Table 1 for 3 pairs of 2 pairs, in which case there is no single slab.

The present inventors have examined the relationship between the combination pattern and the total rolling time, and found that the total rolling time varies depending on the combination pattern of the pair and the rolling order of each pair when performing the tandem rolling. A method for determining the rolling order of slabs that can shorten the total rolling time by selecting a combination pattern was completed.

FIG. 2 is a diagram showing a flow of a method for determining the rolling order of slabs in the present invention.
When a plurality of controlled rolled materials that are subjected to finish rolling after rough rolling and cooling the slab to be rolled are included, first, a plurality of pairs of slabs are made into pairs every two as shown in Tables 1 and 2 above. A combination pattern is created (S-1).
This combination pattern is created for all combinations calculated by the above-described equation (A).

Next, whether the cooling time of the preceding material exceeds the rough rolling time of the succeeding material (S-2), or whether the cooling time of the following material exceeds the finish rolling time of the preceding material (S-3) Check to make tandem rolling possible when both conditions are satisfied, and tandem rolling is not possible if these conditions are not met.
When tandem rolling is performed without satisfying both of the conditions (S-2) and (S-3), the cooling time of either the preceding material or the succeeding material is exceeded and a predetermined material is secured. This is because there are cases where it becomes impossible.
When tandem rolling is possible, the total rolling time from the start of rough rolling of the preceding material to the end of finish rolling of the succeeding material is calculated (S-4).
This total rolling time is calculated according to the rolling procedure shown in FIG. 1 and takes into account the allowance time for avoiding interference between the preceding material and the following material and the shortening of the cooling time when cooling by water cooling instead of air cooling. It is preferable.

If tandem rolling is not possible (No in S-2 and S-3), the total rolling time of the preceding material and the following material is calculated (S-5).
Further, the same processing is performed by changing the order of the preceding material and the succeeding material, and the combination pattern having the shortest total rolling time is selected and rolled (S-6).
In addition, when the said control rolling material is an odd number, the steel sheet which was not paired can calculate the exact total rolling time by calculating | requiring the rolling time, and adding to the said total rolling time.
By the above procedure, the total rolling time is calculated after determining whether or not tandem rolling can be performed for all the combination patterns and the rolling order of each pair that form a pair of slabs including a plurality of control rolled materials, The most efficient rolling can be performed by selecting and rolling a combination pattern that minimizes the rolling time of all slabs.

Tables 3 to 5 show the results of applying the method for determining the rolling order of slabs of the present invention to six slabs from a control rolled material for thick steel plates.
Table 3 shows the rough rolling time (t1), the cooling time (t2), and the finish rolling time (t3) preset according to the specifications of each of the six slabs.
Table 4 shows a combination pattern of the preceding material and the following material.
Table 5 shows the shortest rolling time in each combination pattern.
The calculation formula of the tandem rolling time T used in this example is shown below.
T = t1a + t1b + t2b + t3b
Where t1a: rough rolling time of the preceding material,
t1b: rough rolling time of the following material,
t2b: cooling time of the following material,
t3b: finish rolling time of the following material,
This equation shows the case of air cooling at the front of the rolling mill, but forced cooling may be provided by providing a cooling device. In this case, the cooling time t2b of the succeeding material is shortened, and the cooling time t2bo at that time is ,
t2bo = t2a-t1b + t3a
+ (T2b-t2a + t1b-t3a) / db, and the above equation becomes T = t1a + t1b + t2bo + t3b.
However, db shows the cooling ratio of the cooling by the cooling device of the rolling mill front surface, and air cooling.
Moreover, a cooling device may be provided on the rear surface of the rolling mill for forced cooling,
In that case, since the cooling time t2a of the preceding material is shortened,
t2ao = t1b + (t2a-t1b) / da.
However, since this t2ao is not related to the T formula, it is relevant when any or all of the target materials (six in this example) are not tandem rolled.
As shown in Table 5, among the combinations of 15 patterns, the total rolling time was the shortest in 1851 seconds of NO.8 and NO.15. By adopting this pattern, the most efficient slab It was confirmed that rolling could be realized.

It is a figure which shows the rolling procedure of the tandem rolling used for this invention. It is a figure which shows the flow of the rolling order determination method of the slab in this invention.

Claims (2)

A method for determining the rolling order of a slab including a plurality of control rolled materials that are subjected to finish rolling after rough rolling and cooling,
A step of creating a plurality of combination patterns in which the slab is paired every two of the preceding material and the following material;
When the time for cooling the preceding material exceeds the rough rolling time of the succeeding material and the cooling time of the following material exceeds the finish rolling time of the preceding material, tandem rolling is possible, and this condition is not satisfied. The process of making tandem rolling impossible,
In the case where the tandem rolling is possible, a step of calculating a total rolling time from the rough rolling start of the preceding material to the finish rolling finish of the succeeding material;
In the case where the tandem rolling is impossible, a step of calculating a total rolling time of the preceding material and the following material,
A method for determining the rolling order of a slab, wherein the same processing is performed by changing the order of the preceding material and the succeeding material, and the combination pattern having the smallest total rolling time is selected and rolled. The method for determining the rolling order of slabs according to claim 1, wherein when the number of controlled rolled materials is an odd number, one slab that has not been paired is calculated for the rolling time and added to the total rolling time. .

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