JP3411163B2 - Determination of Rolling Order of Steel Sheet in Hot Rolling Continuous Process - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling equipment for producing a hot rolled steel sheet, in which a rear end portion of a moving preceding steel sheet and
The present invention relates to a method for determining a rolling order of steel sheets in a so-called hot rolling continuous process in which the leading end portions of subsequent steel sheets are joined and a plurality of steel sheets are continuously rolled.

[0002]

2. Description of the Related Art In conventional hot rolling, the rolling order of rolled materials is such that the width of the product strip is reduced from that of the product strip in consideration of the effect of the wear of the rolling rolls on the product, and the finish rolling strip thickness. It has been common to roll the product from a thick product to a thin product in consideration of the influence on the quality due to the abrupt change of the product and the easiness of passing. In recent years, direct rolling (a method of rolling a slab with a continuous casting machine at a high temperature through a heating furnace or a soaking furnace) is used to maximize its effect and to align the rolling order. Since it was necessary to consider the trade-off of effects, the operator decided the rolling order.

To solve this, for example, Japanese Patent Laid-Open No.
In Japanese Patent Laid-Open No. 8-35001, a method is proposed in which a rolling order can be determined by a computer based on information of a rolled material that has been mathematically expressed. However, as described below, the present invention is intended for conventional hot rolling. However, the main point is how to set the rolling order of the steel sheets in the rolling of hot-rolled steel sheets by the hot-rolling continuous process of joining and rolling the steel sheets before finish rolling. That is, it is a steel plate rolling order determination method for maximizing the effects of the continuous rolling process as described below.

In recent years, a so-called hot rolling continuous process has been attempted in which a plurality of steel plates after rough rolling are sequentially joined and then hot finish rolling is continuously performed at a predetermined speed. In the conventional manufacturing process, since each slab is rolled, the steel plate front,
Abnormal quality such as dimensional defects, shape defects, and appearance defects are likely to occur in the unsteady part of the tail, resulting in a decrease in steel plate yield and an increase in work processes. However, by applying the continuous rolling process, it becomes a full-length middle part, and the above problems can be improved to significantly reduce costs and improve quality,
Needless to say, this effect depends on how many steel plates are continuously rolled. The present invention is a method of determining a rolling order from the viewpoint of improving the number of continuous rollings on the premise of a hot rolling continuous rolling process, which is unprecedented in the past.

[0005]

Various means have been proposed for the continuous hot rolling process, and an example thereof is a facility as shown in FIG. FIG. 1 is a diagram showing an equipment arrangement for carrying out the present invention.

The slab heated in the heating furnace is roughly rolled by the rough rolling mill and then wound by the coil box. After the rough rolling coil in this coil box is unwound and the front and rear end portions are cut by a cutting machine for joining, a joining device (the joining device is not particularly limited, and various joining methods are also available). (Considerable), the trailing edge of the preceding material and the leading edge of the trailing material are joined, and finish rolling is performed by the finish rolling mill. Further, the steel sheet after the finish rolling is wound by a winder through a cooling floor and a pinch roll. At that time, the joint is cut by a cutting machine. Therefore, endless rolling is performed by finish rolling on the part excluding the front end of the first steel plate and the rear end of the last steel plate.

In the continuous hot rolling process, the strength of the joint is generally inferior to that of the other base materials, and depending on the joining method, there is a change in thickness or temperature fluctuation near the joint. Often accompanied. Therefore, when finish-rolling the joint, the joint is likely to break due to the change in the thickness and the change in the tension between the finish rolling stands caused by the temperature change.

Under these circumstances, following the conventional way of thinking about the rolling order of steel sheets (ie, joining order), the material conditions of the preceding material and the following material (sheet thickness of sheet steel, sheet width, composition, sheet thickness at the finishing machine side) Etc.) changes significantly, the mass flow rate of the steel sheet between the stands changes greatly, and the change of the finish rolling mill control (mainly tension control) cannot follow this change, and the tension between the finish stands further increases. If the tension fluctuates significantly and the tension exceeds the strength of the joint, it breaks, and if it is in a tension-free state, the passage of the plate due to meandering etc. of the plate will occur and the continuation must be interrupted. For,
The number of continuous lines was low.

The present invention avoids the above-mentioned troubles by keeping the variation of the tension of the steel sheet between the finishing stands within a limited range, and improves the number of continuous lines, and the advantages obtained by the continuous process The object of the present invention is to provide a method for determining the order of rolling steel sheets that allows the maximum enjoyment of the above.

[0010]

The present invention has been made in order to solve the above problems and takes the following means. A method for determining the order of rolling of steel sheets in a hot rolling continuous process, in which when joining and rolling the preceding steel sheet and the following steel sheet immediately before hot finish rolling, the plate thicknesses of the two steel sheets to be joined are
Regarding the difference, the allowable maximum thickness change ratio Hm (Hm> 0)
Based on the allowable limit of tension fluctuation between finishing stands,
A method for determining a rolling order of steel sheets in a hot rolling continuous process, characterized by determining the steel sheet rolling order so as to satisfy the following formula (1) by being obtained by a simulation or a test . | H / Hm | ≦ 1 (1) where H = (Hj−Hi) / Hi Hi: plate thickness of preceding steel plate Hj: plate thickness of subsequent steel plate

A method for determining the order of rolling of steel sheets in a hot rolling continuous process, wherein when the preceding steel sheet and the following steel sheet are joined and rolled immediately before hot finish rolling , the difference in the sheet width between the joined steel sheets is , Allowable maximum plate width change ratio Wm (Wm>
0) based on the allowable limit of tension fluctuation between finishing stands
A method for determining a rolling order of steel sheets in a hot rolling continuous process , which is obtained in advance by simulation or testing, and the steel sheet rolling order is determined so as to satisfy the following formula (2). | W / Wm | ≦ 1 (2) where W = (Wj−Wi) / Wi Wi: plate width of preceding steel plate Wj: plate width of succeeding steel plate

A method for determining the order of rolling of steel sheets in a hot rolling continuous process, wherein when the preceding steel sheet and the following steel sheet are joined and rolled immediately before hot finish rolling , regarding the difference in the components of the two steel sheets to be joined , Allowable maximum carbon equivalent change ratio Cm (Cm
> 0) based on the allowable limit of tension fluctuation between finishing stands
In advance by simulation or test,
A method for determining a rolling order of steel sheets in a hot rolling continuous process, characterized in that a steel sheet rolling order is determined so as to satisfy the following expression (3). | C / Cm | ≦ 1 ··· (3) However, C = (Cj-Ci) / Ci Ci: prior steel carbon equivalent of Cj: carbon equivalent of the trailing steel

A method for determining a rolling order of steel sheets in a hot rolling continuous process, wherein when a preceding steel sheet and a following steel sheet are joined and rolled immediately before hot finish rolling, a finishing rolling mill delivery side plate of both joined steel sheets Maximum permissible finishing mill for thickness differences
Set the outlet plate thickness change ratio Tm (Tm> 0) between the finishing stands.
Pre-simulation based on the allowable limit of force fluctuation or
A method for determining a rolling order of steel sheets in a hot rolling continuous process, which is determined by a test and determines a steel sheet rolling order so as to satisfy the following formula (4). | T / Tm | ≦ 1 (4) However, T = (Tj-Ti) / Ti Ti: Finishing rolling mill delivery side plate thickness of the preceding steel plate Tj: Finishing rolling mill delivery side plate thickness of the following steel plate

A method for determining the order of rolling of steel sheets in a hot rolling continuous process, wherein when joining and rolling a preceding steel sheet and a following steel sheet immediately before hot finish rolling, the thickness and width of both steel sheets to be joined are Regarding the difference in the composition, the composition, and the strip thickness of the finishing mill ,
Allowable maximum plate thickness change ratio Hm (Hm> 0), Allowable maximum plate width change
Conversion ratio Wm (Wm> 0), maximum allowable carbon equivalent change ratio Cm
(Cm> 0), allowable maximum finish rolling mill exit side plate thickness change ratio Tm
(Tm> 0) as the allowable limit of tension fluctuation between finishing stands
Based on a preliminary simulation or test
Then, a method for determining the rolling order of steel sheets in the hot rolling continuous process, characterized in that the steel sheet rolling order is determined so as to satisfy the following formula (5). | (H / Hm) + (W / Wm) + (C / Cm) | + | (T / Tm) | ≦ 1 (5) where H = (Hj-Hi) / Hi Hi: preceding steel plate Thickness of the trailing steel plate, Hj: W = (Wj-Wi) / Wi, Wi: the width of the preceding steel plate, Wj: the width of the following steel plate, C = (Cj-Ci) / Ci Ci: the preceding steel plate. carbon equivalent of, Cj: carbon equivalent T = (Tj-Ti) / Ti Ti of the trailing steel: plate out finishing mill prior steel thickness Tj: thickness at delivery side of the finishing mill of the trailing steel

A method for determining the order of rolling of steel sheets in a hot rolling continuous process, wherein when joining and rolling a preceding steel sheet and a following steel sheet immediately before hot finish rolling, the thickness and width of both steel sheets to be joined are Regarding the difference in the composition, the composition, and the strip thickness of the finishing mill ,
Allowable maximum plate thickness change ratio Hm (Hm> 0), Allowable maximum plate width change
Conversion ratio Wm (Wm> 0), maximum allowable carbon equivalent change ratio Cm
(Cm> 0), allowable maximum finish rolling mill exit side plate thickness change ratio Tm
(Tm> 0) and weighting factor a (0 <a <1)
Based on the allowable limit of tension fluctuation between
A method for determining the order of rolling of steel sheets in a hot rolling continuous process, characterized in that the order of rolling steel sheets is determined so as to satisfy the following formula (6). | (H / Hm) + (W / Wm) + (C / Cm) | + | (T / Tm) | -a * | (H / Hm) + (W / Wm) + (C / Cm) | * | (T / Tm) | ≦ 1 (6) where H = (Hj−Hi) / Hi Hi: thickness of preceding steel plate, Hj: thickness of succeeding steel plate W = (Wj−Wi) / Wi Wi: plate width of the preceding steel plate, Wj: plate width of the following steel plate C = (Cj-Ci) / Ci Ci: carbon equivalent of the preceding steel plate, Cj: carbon equivalent T = (Tj-Ti) / of the following steel plate Ti Ti: Finishing strip thickness of the preceding rolling plate Tj: Finishing strip thickness of the following rolling plate

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION When the present invention performs the rolling of a steel sheet in a hot rolling continuous rolling process by joining the steel sheets from a roughing machine in hot rolling, the steel sheet is ruptured between finishing stands, and On the contrary, various studies were conducted on how to avoid a tensionless state, and when a rolling simulation was actually performed in accordance with the rolling sequence based on the concept of the conventional discontinuous rolling method, the above fracture or tensionlessness occurred. In some cases, the continuation of rolling can be carried out without doing it, and in other cases, the continuation of rolling must be interrupted due to the occurrence of the breakage or tension. Therefore, as a result of many studies in pursuit of this cause, the present invention has been developed.

The gist of the present invention is to prevent the joints from breaking due to the generation of tension exceeding the strength of the joints between the finishing stands, or to prevent the plate from meandering or obstructing the passage due to the occurrence of a tensionless state. Setting the allowable limit for the tension fluctuation value, the allowable maximum change ratio (plate thickness of the steel plate, plate width, composition, exit plate thickness of the finishing rolling mill) before and after the joint for each material condition set by that is obtained, and the joint is performed. The rolling order of the rolled steel sheets is determined so that the change ratio of the material conditions before and after the part does not exceed this value, thereby maximizing the continuous number of hot rolling.

The main cause of the tension fluctuation (mass flow fluctuation) between the finishing stands is the fluctuation caused by the stepwise change of the steel plate conditions (steel plate thickness, width, composition) before and after the joining portion, and the positive finish. There are two fluctuations that occur when the exit side plate thickness of the finish rolling mill is changed in the vicinity of the joining point by operating the reduction in the rolling mill and changing the running plate thickness.

Among the conditions of the steel sheet, the component difference is a coefficient corresponding to the deformation resistance during finish rolling, and it is preferable to consider the component and temperature, but in practical use, the carbon equivalent (hereinafter referred to as CEQ, CEQ = Cwt% + Mn / 6w simply
The purpose can be sufficiently achieved by setting the value as t%). Tension fluctuation (mass flow fluctuation) between the finishing stands
It is preferable that the allowable maximum change ratio of each factor is determined in advance by simulation or test.

Here, since the mass flow fluctuation between finishing stands is proportional to not only the change ratios of the above factors but also the finishing rolling speed, it is preferable to find the maximum allowable value for each speed category. In the upper part, since there is a correlation between the strip thickness of the finishing rolling mill and the rolling speed, it may be obtained for each strip thickness of the finishing rolling mill.

Further, the permissible maximum change ratio depends not only on the strength of the joint, but also on the component, size (plate thickness, plate width), and the absolute value of the inter-stand tension during rolling set for each stand. It is preferable to obtain the maximum allowable value for each component and size. However, in practice, the objective can be sufficiently achieved by setting the output thickness of each finishing rolling mill. For each factor that causes tension fluctuation between the finishing stands, the form of the tension fluctuation that occurs differs depending on whether each factor changes in the increasing direction or in the decreasing direction. Is preferred.

When each of the factors that cause the tension variation between the finishing stands changes independently, the change ratio is divided by the maximum allowable change ratio at the time of independent change obtained by simulation or test, and is 1 or less. In this case, continuous rolling can be continued without trouble such as breakage. For example, the plate width change ratio of the steel plate before and after the joining point is W,
When the maximum allowable change ratio is Wm, the following expression (2) may be satisfied. | W / Wm | ≦ 1 (2)

In the case where the changes of the factors that cause the tension fluctuation between the finishing stands occur in a complex manner, the sum of the ratios of the respective change ratios to the corresponding maximum allowable change ratios should not exceed 1. However, note the following points at this time. That is, the thickness of the steel plate, the plate width,
Any change in the component is the same type of disturbance that occurs stepwise at the joint, and the principle of simple superposition holds. However, as for the strip thickness of the finishing rolling mill, the mass flow fluctuation that occurs with the change of the strip thickness during the active rolling operation in the finish rolling poses a problem, so it is independent of the above-mentioned stepwise disturbance. Need to handle.

Therefore, when these four factors change in a complex manner, the condition for continuing the continuous rolling is expressed by the following equation (5). | (H / Hm) + (W / Wm) + (C / Cm) | + | (T / Tm) | ≦ 1 (5) where H: plate thickness change ratio Hm: steel plate allowance Maximum plate thickness change ratio (Hm> 0) W: Steel plate width change ratio Wm: Steel plate allowable maximum plate width change ratio (Wm> 0) C: Steel plate component coefficient change ratio Cm: Steel plate allowable maximum component coefficient change Ratio (Cm> 0) T: Ratio of change in plate thickness on exit side of finish rolling mill Tm: Permissible maximum change ratio of plate thickness on exit side of finish rolling machine (Tm> 0) The above equation is a value within the range shown by the diagonal lines in FIG. 2.

Further, change factors that occur stepwise at the joining point, such as changes in the steel plate thickness, plate width, and steel grade, and changes in the finish rolling mill plate thickness that cause mass flow fluctuations with changes in the running plate thickness. Should be treated independently as described above, but generally the peak positions of the mass flow fluctuations due to the two are not the same, so the conditions are usually somewhat relaxed from the conditions defined by the above equation.

In order to express this, the weighting coefficient a (0
If <a <1) is introduced, the above formula (5) becomes the form of the following formula (6). | (H / Hm) + (W / Wm) + (C / Cm) | + | (T / Tm) | -a * | (H / Hm) + (W / Wm) + (C / Cm) | * | (T / Tm) | ≦ 1 (6) where H: Steel plate thickness change ratio Hm: Maximum allowable steel plate thickness change ratio (Hm> 0) W: Steel plate width change ratio Wm: Allowable maximum plate width change ratio (Wm> 0) C: Steel plate component coefficient change ratio Cm: Steel plate allowable maximum component coefficient change ratio (Cm> 0) T: Finishing mill exit side plate thickness change ratio Tm: Allowable maximum Finish rolling mill outlet side plate thickness change ratio (Tm> 0) a: Weighting coefficient (0 <a <1) Here, the weighting factor a is determined by a simulation or after considering a method for changing the finishing rolling mill outlet side plate thickness. The value is determined by a test. The above equation has a value within the range indicated by the diagonal lines in FIG.

Table 1 shows the thickness, width and composition of the steel plates to be joined.
It is the maximum allowable change ratio in the plate thickness on the exit side of the finishing rolling mill,
This is the value in the increasing direction (+ side) and the decreasing direction (-
However, in this example, since the values were the same in both directions, the classification was not performed.

[0028]

[Table 1]

[0029]

[Examples] As examples, the change ratio of each factor and its total change ratio are shown in each table (Tables 2 to 13) on the basis of the values obtained from the above formulas (1) to (6) for an ordinary rolled steel sheet. . As mentioned above, although there are some cases where the respective change ratios are naturally on the + side and the-side due to the factors, since they become clear from the above-mentioned formulas, the + and-are not dared.

Table 2 shows an example in which only the steel plates having the same composition, the same width and the same thickness (coil thickness) as the exit side plate of the finish rolling mill are used, and only the steel plates of which the plate thickness is changed are continuous. The absolute value of the ratio of the plate thickness change ratio H of the preceding steel plate d and the trailing steel plate e of this steel plate to the allowable maximum plate thickness change ratio Hm becomes larger than 1, and a tension-free state occurs between the finishing stands, which makes rolling impossible. This is an example in which continuation must be interrupted, and an example in which the same steel plates are rearranged to enable continuation without generating a tension-free state between finishing stands is shown in Table 3. It was

[0031]

[Table 2]

[0032]

[Table 3]

Similarly, this is an example of the case where only the steel plate having the same composition, the same plate thickness, and the same coil thickness and only the plate width of the steel plate is made continuous, and the preceding steel plate d and the following steel plate The absolute value of the ratio between the plate width change ratio W of the steel plate e and the maximum allowable plate width change ratio Wm becomes larger than 1, and there is a risk of breakage between the finishing stands and unrollable, so continuation is interrupted. Table 4 shows an example of what must be done, and Table 5 shows an example in which the same steel sheets are rearranged so that continuation can be achieved between the finishing stands without causing breakage.

[0034]

[Table 4]

[0035]

[Table 5]

Further, in the case where only the steel plate having the same plate width, plate thickness and coil thickness and having only the components of the steel plate changed to be continuous, the preceding steel plate e and the following steel plate f of this steel plate are continuous.
The absolute value of the ratio of the component coefficient change ratio C of C to the allowable maximum component coefficient change ratio Cm becomes larger than 1, and there is a possibility that a tensionless state may occur between the finishing stands and rolling may not be possible. Table 6 shows an example of what must be done, and Table 7 shows an example in which the same steel sheets are rearranged so that the finishing stands can be made continuous without generating a tensionless state.

[0037]

[Table 6]

[0038]

[Table 7]

Further, this is an example of the case where only the steel plates having the same composition, plate thickness, and plate width and having only the coil thickness changed are made continuous, and the preceding steel plate b and the following steel plate e of this steel plate are shown. Coil thickness change ratio T and allowable maximum coil thickness change ratio Tm
When the absolute value of the ratio becomes larger than 1, there is a possibility that breakage occurs between finishing stands and rolling becomes impossible, and continuation must be interrupted. Table 9 shows an example in which continuation can be performed without causing breakage between the finishing stands.

[0040]

[Table 8]

[0041]

[Table 9]

Furthermore, this is a case where the fluctuations of the respective factors of the steel plate described above are combined, and | (H / Hm) + (W / Wm) + (C / Cm of the preceding steel plate a and the following steel plate b of this steel plate. ) ｜
The value of + | (T / Tm) | (total Ta) becomes larger than 1 and there is a possibility that a tensionless state may occur between the finishing stands and rolling may not be possible. Table 11 shows an example in which the same steel plates are rearranged to enable continuation without generating a tensionless state between the finishing stands.

[0043]

[Table 10]

[0044]

[Table 11]

Similarly, the variation of each factor is combined and weighted (a = 0.5 in this example), and | (H / H of the leading steel plate a and the trailing steel plate b of this steel plate). H
m) + (W / Wm) + (C / Cm) | + | (T / Tm)
│-a × │ (H / Hm) + (W / Wm) + (C / Cm)
The value of | × | (T / Tm) | (total Tb) becomes larger than 1, there is a possibility that breakage may occur between the finishing stands and rolling may not be possible. Table 13 shows examples in which the same steel sheets are rearranged to enable continuity without causing breakage between the finishing stands.

[0046]

[Table 12]

[0047]

[Table 13]

Those which cannot be made continuous are listed in Table 2 above.
In Table 4, Table 6, Table 8, Table 10 and Table 12, those in which the change ratio exceeds 1 in each of the tables are applicable. On the other hand, Examples of the present invention are shown in Table 3, Table 5, Table 7, Table 9, Table 11 and Table 13, but none of them exceed 1, and it is impossible to make continuous in the rolling order of the conventional lot. However, in the present invention, by changing the rolling order, all the steel sheets could be continuously continuous and rolled.

[0049]

EFFECTS OF THE INVENTION According to the present invention, many steel sheets can be continuously rolled without any adverse effect due to steel sheet breakage between the finishing roll stands or tensionlessness due to the hot rolling continuous process, so that productivity is improved. In addition, it can greatly contribute to cost reduction and quality stabilization.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of equipment for a hot rolling continuous process.

FIG. 2 is a diagram showing a range in which continuation is possible when each factor changes in a complex manner.

FIG. 3 is a diagram showing a continuous possible range when a weighting factor is taken into consideration when each factor is changed in a complex manner.

Claims (6)

(57) [Claims] 1. A method for determining the order of rolling of steel sheets in a hot rolling continuous process, wherein the thicknesses of both steel sheets to be joined when joining and rolling the preceding steel sheet and the following steel sheet immediately before hot finish rolling.
With respect to the difference of, the maximum allowable thickness change ratio Hm (Hm> 0)
Based on the allowable limit of tension fluctuation between finishing stands.
A method for determining a rolling order of steel sheets in a hot rolling continuous process, characterized by determining a steel sheet rolling order so as to satisfy the following formula (1) by being obtained by a simulation or a test . | H / Hm | ≦ 1 (1) where H = (Hj−Hi) / Hi Hi: plate thickness of preceding steel plate Hj: plate thickness of subsequent steel plate 2. A method for determining the order of rolling of steel sheets in a hot rolling continuous process, wherein when the preceding steel sheet and the trailing steel sheet are joined and rolled immediately before hot finish rolling, the sheet width of both steel sheets to be joined.
With regard to the difference of, the maximum allowable width change ratio Wm (Wm> 0)
Based on the allowable limit of tension fluctuation between finishing stands.
A method for determining a rolling order of steel sheets in a hot rolling continuous process, characterized in that the rolling order of steel sheets is determined so as to satisfy the following expression (2) by a simulation or a test . | W / Wm | ≦ 1 (2) where W = (Wj−Wi) / Wi Wi: plate width of preceding steel plate Wj: plate width of succeeding steel plate 3. A method for determining the order of rolling of steel sheets in a hot rolling continuous process, wherein the components of both steel sheets to be joined at the time of joining and rolling the preceding steel sheet and the following steel sheet immediately before hot finish rolling.
The maximum allowable carbon equivalent change ratio Cm (Cm>
0) based on the allowable limit of tension fluctuation between finishing stands
A method for determining a rolling order of steel sheets in a hot rolling continuous process , which is obtained in advance by a simulation or a test, and the steel sheet rolling order is determined so as to satisfy the following formula (3). | C / Cm | ≦ 1 ··· (3) However, C = (Cj-Ci) / Ci Ci: prior steel carbon equivalent of Cj: carbon equivalent of the trailing steel 4. A method for determining the order of rolling of steel sheets in a hot rolling continuous process, which comprises a finish rolling machine for joining both steel sheets when joining and rolling the preceding steel sheet and the following steel sheet immediately before hot finish rolling. Regarding the difference in the strip thickness on the delivery side , the maximum allowable finish rolling mill is released.
The side plate thickness change ratio Tm (Tm> 0) is defined by the tension between the finishing stands.
Simulation or trial based on the allowable limit of fluctuation
A method for determining a rolling order of steel sheets in a hot rolling continuous process, which is determined by an experiment and determines a steel sheet rolling order so as to satisfy the following formula (4). | T / Tm | ≦ 1 (4) However, T = (Tj-Ti) / Ti Ti: Finishing rolling mill delivery side plate thickness of the preceding steel plate Tj: Finishing rolling mill delivery side plate thickness of the following steel plate 5. A method for determining the order of rolling of steel sheets in a hot rolling continuous process, wherein when the preceding steel sheet and the following steel sheet are joined and rolled immediately before hot finish rolling, the thicknesses of the two steel sheets to be joined, Regarding the difference in strip width, composition, and strip thickness at the finish rolling mill ,
Allowable maximum plate thickness change ratio Hm (Hm> 0), Allowable maximum plate width change
Conversion ratio Wm (Wm> 0), maximum allowable carbon equivalent change ratio Cm
(Cm> 0), allowable maximum finish rolling mill exit side plate thickness change ratio Tm
(Tm> 0) as the allowable limit of tension fluctuation between finishing stands
Based on a preliminary simulation or test
Then, a method for determining the rolling order of steel sheets in the hot rolling continuous process, characterized in that the steel sheet rolling order is determined so as to satisfy the following formula (5). | (H / Hm) + (W / Wm) + (C / Cm) | + | (T / Tm) | ≦ 1 (5) where H = (Hj-Hi) / Hi Hi: preceding steel plate Thickness of the trailing steel plate, Hj: W = (Wj-Wi) / Wi, Wi: the width of the preceding steel plate, Wj: the width of the following steel plate, C = (Cj-Ci) / Ci Ci: the preceding steel plate. carbon equivalent of, Cj: carbon equivalent T = (Tj-Ti) / Ti Ti of the trailing steel: plate out finishing mill prior steel thickness Tj: thickness at delivery side of the finishing mill of the trailing steel 6. A method of determining the order of rolling of steel sheets in a hot rolling continuous process, wherein the thickness of both steel sheets to be joined when joining and rolling the preceding steel sheet and the following steel sheet immediately before hot finish rolling, Regarding the difference in strip width, composition, and strip thickness at the finish rolling mill ,
Allowable maximum plate thickness change ratio Hm (Hm> 0), Allowable maximum plate width change
Conversion ratio Wm (Wm> 0), maximum allowable carbon equivalent change ratio Cm
(Cm> 0), allowable maximum finish rolling mill exit side plate thickness change ratio Tm
(Tm> 0) and weighting factor a (0 <a <1)
Based on the allowable limit of tension fluctuation between
A method for determining the order of rolling of steel sheets in a hot rolling continuous process, characterized in that the order of rolling steel sheets is determined so as to satisfy the following formula (6). | (H / Hm) + (W / Wm) + (C / Cm) | + | (T / Tm) | -a * | (H / Hm) + (W / Wm) + (C / Cm) | * | (T / Tm) | ≦ 1 (6) where H = (Hj−Hi) / Hi Hi: thickness of preceding steel plate, Hj: thickness of succeeding steel plate W = (Wj−Wi) / Wi Wi: plate width of the preceding steel plate, Wj: plate width of the following steel plate C = (Cj-Ci) / Ci Ci: carbon equivalent of the preceding steel plate, Cj: carbon equivalent T = (Tj-Ti) / of the following steel plate Ti Ti: Finishing strip thickness of the preceding rolling plate Tj: Finishing strip thickness of the following rolling plate