WO2019138908A1

WO2019138908A1 - Shaped steel rolling method, shaped steel manufacturing line, and shaped steel manufacturing method

Info

Publication number: WO2019138908A1
Application number: PCT/JP2018/048177
Authority: WO
Inventors: 和典関; 弘之石橋
Original assignee: 日本製鉄株式会社
Priority date: 2018-01-10
Filing date: 2018-12-27
Publication date: 2019-07-18
Also published as: EP3702058A1; AU2018400555A1; JPWO2019138908A1; JP6551625B1; US20200338608A1

Abstract

According to the present invention, for each rolling machine, a rolling torque Gi before biting at a downstream stand is stored, the rotation speed at a furthest downstream stand Rn is controlled so as to satisfy Gn-1=Gn-1* after biting at the furthest downstream stand Rn, and a rolling torque Gn** of Rn after tension correction is stored. Subsequently, the rotation speed of a rolling machine Ri is controlled so as to satisfy Gi=Gi* toward the upstream side, and the rotation speed of a rolling machine Rk on the downstream side of the rolling machine Ri is controlled so as to maintain the relationship Gk=Gk** (k=1+1 to n), and the rolling torque of a furthest upstream rolling machine R1 is controlled to be equal to the stored G1*. Thus, even under the condition of small distances between stands, the tension between stands is controlled with high accuracy in a simple control system that does not use table values for each rolling condition, and stabilization of a passing material and improvement of product dimensions are achieved.

Description

Method of rolling shape steel, manufacturing line of shape steel and method of manufacturing shape steel

(Cross-reference to related applications)
Priority is claimed on Japanese Patent Application No. 2018-001784, filed January 10, 2018, the content of which is incorporated herein by reference.

The present invention relates to, for example, a method of rolling a shaped steel for producing shaped steels such as H-shaped steel, T-shaped steel, and I-shaped steel, a production line of shaped steel, and a method of manufacturing shaped steel.

In a rolling process using a continuous rolling mill, material tension between the rolling mills is an important factor for determining dimensions such as thickness and width of the material. Therefore, in order to keep the product size well, it is required to control the tension between the rolling mills appropriately. In view of such circumstances, a technology for performing tension control between various rolling mills (also referred to as a rolling stand and a stand) has conventionally been devised.

For example, Patent Document 1 discloses a technique for performing tension control between stands of a continuous rolling mill. Specifically, in Patent Document 1, the relationship between the rolling torque, rolling load, front tension, and back tension of each rolling stand is linearly related, and the front tension and back tension are measured based on the measured values of the rolling torque and the rolling load. Control is performed by estimating and using the estimated value as a target value.

Further, for example, in Patent Document 2, in a continuous rolling mill having two or more rolling mills, the current of the roll drive motor when the material to be rolled bites into the reference rolling mill is stored, and the next rolling is performed. A technology is disclosed that performs speed control as compared to the current of a roll drive motor when a material to be rolled is caught in a machine.

Further, for example, Patent Document 3 discloses a technique of detecting only torque fluctuation due to forward tension between a plurality of stands of a tandem rolling mill, and controlling tension between the respective stands. Specifically, in Patent Document 3, the rolling torque of a state in which the material to be rolled does not bite into the downstream side stand at an arbitrary stand, and the rolling torque of the upstream side stand at that time, An arrangement for determining tension free torque is disclosed.

JP, 2008-183594, A Japanese Patent Publication No. 53-34586 Japanese Patent Publication No. 61-3564

Although tension control between stands (rolling machines) is essential in a continuous rolling mill consisting of a plurality of rolling mills, in the technique described in Patent Document 1, in order to estimate the tension between the stands from a linear form, a linear system is prepared in advance. It is necessary to create a linear form by extensive experiments and numerical analysis.

The technology described in Patent Document 2 is based on the premise that the tension between the rolling mill and the reference rolling mill can be controlled to no tension before the material to be rolled bites into the rear stage stand (the next rolling mill). If the distance between them is short, there is a possibility that it can not be applied.

Further, the technology described in Patent Document 3 is considered to be premised that the sum of rolling torques is constant regardless of tension, and when there is an error in the premise, an error occurs in the tension control between stands as well. There is a risk that the tension control may not be performed accurately. Further, the technology of Patent Document 3 is basically created on the premise of rolling of a wire rod or a steel plate, and an error may occur when it is applied to a shaped steel rolled by a universal rolling mill. The reasons will be briefly described below in [0011] to [0016].

In the said patent document 3, tension control between stands of a tandem rolling mill is performed using following formula (1), (2).

The above equation is considered to be based on the assumption that the total rolling torque at the total stand is constant regardless of tension. As an example, consider the case where the total stand is three stands (first to third stands). Based on the equations (1) and (2), the rolling torque G at each stand can be derived from the relationships shown in the following equations (A1) and (A2).

These equations (A1) and (A2) are based on the premise that the total work amount of all the stands is constant regardless of the tension state. The tension changes the shape of the material to be rolled in the cross section, and the total amount of work changes. Specifically, in the universal rolling of shaped steel, there is a pressure reduction due to the side surface of the horizontal roll and the circumferential surface of the weir roll, and different frictional force depending on the position acts on the side surface of the horizontal roll and the circumferential surface of the weir roll and the material to be rolled In order to change the size of the material to be rolled due to the tension between the stands, the total work may vary. Therefore, it is appropriate that the relationship between tension and rolling torque G is expressed by the following equations (B1) to (B3) including the influence coefficient. In addition, below, as tension T between each stand, tension between the first and second stands is T12, tension between the second and third stands is denoted as T23, and A12, A23, B12, B23 are It is an influence factor between each stand.

In the above equations (B1) to (B3), if A12 = B12 and A23 = B23, the relationships shown in the above equations (A1) and (A2) hold, but as described above, the total work amount in rolling of shaped steel However, the relationship between A12 = B12 and A23 = B23 may not hold.

When comparing the formula (A1) with the formulas (B1) and (B2), the formulas (B1) and (B2) can be obtained before the material to be rolled bites into the third stand (that is, T23 = 0). If it deform | transforms, the following formula (B4) will be derived | led-out.

Formula (A1) and Formula (B4) which are formulas for deriving the 2nd stand rolling torque G20 at the time of no tension of a 2nd stand are written together below, and Formula (B4) is further transformed to Formula (B4) 'And compare.

From the comparison between the formula (A1) and the formula (B4) or the formula (A1) and the formula (B4) ′, tension control in rolling of shaped steel is performed using the formulas (1) and (2) described in Patent Document 3. When it is performed, it is understood that an error of (B12 / A12-1) (G1 * -G10) =-(A12-B12) T12 is included.

The above-described error also increases as the inter-stand tension T12 increases. In rolling in a general row of rolling mills, tension is applied (that is, T12> 0) to prevent passing defects during biting, so in the case of no tension when A12> B12 The second stand rolling torque G20 of the above is excessively calculated, and in the case of A12 <B12, the second stand rolling torque G20 without tension is excessively calculated.

Here, numerical analysis showing that the total work amount is not constant in rolling of shaped steel will be described with reference to FIGS. FIG. 9 is a schematic explanatory view of the universal intermediate rolling of H-section steel, (a) is a front view, (b) is a plan view at two stands. In FIG. 9, an H-shaped steel having an inner diameter Bi = 274 mm and a flange width Bf = 150 mm was rolled by a two-stand tandem universal rolling mill. The rolling conditions were such that the web thickness t was 11.4 mm → 10.0 mm → 9.0 mm, and the flange thickness tf 17.2 mm → 14.8 mm → 13 mm.

FIG. 10 is a graph showing by numerical analysis the amount of change in torque (ton · m) of each stand when the tension (tonf) between the first stand R1 and the second stand R2 changes under such rolling conditions It is. When the influence coefficients A12 and B12 are the same, it is considered that the amount of change in torque of each stand is opposite in polarity and inclination is the same. However, as shown in FIG. 10, the inclination is different between the torque change amount of the first stand R1 and the torque change amount of the second stand R2, and it is understood that A12> B12. That is, when the tension control based on Patent Document 3 is performed under the rolling condition of such shape steel, the second stand rolling torque G20 in the absence of tension is underestimated.

Also from the results of such numerical analysis, in the rolling of shaped steel, the shape of the material to be rolled changes due to the tension between the stands, and there is a reduction due to the side surface of the horizontal roll and the circumferential surface of the weir roll. It is estimated that the total amount of work fluctuates due to the effect of different frictional forces depending on the position between the and the rolled material.

By the way, in continuous rolling equipment where energy saving and cost saving are required, the distance between the stands of a plurality of stands may be shortened in an effort to make the equipment compact. When tandem rolling is performed, if the distance between the stands is shortened, a state occurs in which the material to be rolled bites into the downstream stand before the distance between the upstream rolling stands is controlled to no tension, and the above-described tension control technology Such prior art may not be applicable. For example, under the condition that the recovery from the decrease in rotational speed immediately after biting in each rolling stand (so-called impact drop) is about 0.5 seconds, and the biting speed in each rolling stand is 3 m / s, If the distance between stands is 1.5 m or less, there is a possibility that tension control may not be in time until the material to be rolled in the downstream stand is caught.

Then, in view of the above-mentioned circumstances, the object of the present invention is the conditions under which the distance between stands is short when rolling a shaped steel using a continuous rolling mill consisting of three or more rolling mills in a tandem state. Even with a simple control system that does not use table values for each rolling condition, it is possible to control the tension between stands with high accuracy, and to achieve the stabilization of the material passing and the improvement of the product dimensional accuracy. It is an object of the present invention to provide a method, a production line of shaped steel and a method of producing shaped steel.

In order to achieve the above object, according to the present invention, when performing tandem rolling in a rolling mill row composed of at least three or more n rolling mills, one or more rolling mills may use horizontal roll side surfaces and the like. It is a rolling method of shaped steel which performs pressure reduction with a persimmon roll peripheral surface, and about each rolling mill Ri of the rolling mill row, after a rolling material bites in the rolling mill Ri, and, Before the material to be rolled bites into the rolling mill Ri + 1 located downstream of the rolling mill Ri, the rotational speed of the rolling mill Ri is fixed, and the rolling torque Gi of the rolling mill Ri at that time is stored as Gi *. After the material to be rolled bites into the most downstream rolling mill Rn of the row of rolling mills, the rolling torque Gn-1 of the rolling mill Rn-1 located upstream of the rolling mill Rn is rolled to the rolling mill Rn Rolling of the rolling mill Rn-1 before the material bites The first control step of controlling the rotational speed of the rolling mill Rn to be equal to Gn-1 * stored as torque, and the rolling torque Gn ** of the rolling mill Rn after the first control step The rolling torque Gn-2 of the rolling mill Rn-2 located upstream of the rolling mill Rn-1 is stored before the rolling mill Rn-2 before the material to be rolled bites into the rolling mill Rn-1. The rolling speed of the rolling mill Rn-1 is controlled to be equal to Gn-2 * stored as the rolling torque of a rolling torque, and the rolling torque Gn ** in which the rolling torque Gn of the rolling mill Rn is stored A second control step of controlling the number of revolutions of the rolling mill Rn to be equal, the second control step is applied to all the rolling mills Ri, and the rolling torque G1 of the uppermost rolling mill R1 is , A rolling mill R2 located downstream of the rolling mill R1 The rolling method of a shaped steel is provided, characterized in that the number of revolutions of each rolling mill Ri of the rolling mill row is controlled to be equal to G1 * stored as the rolling torque of the rolling mill R1 before biting. Be done. However, i is an arbitrary integer of 1 to n, and n is an integer of 3 or more.

Control using the torque arm coefficient (G / P), which is a value obtained by dividing the rolling torque of each rolling mill by the rolling load of the rolling mill instead of the rolling torque value of each rolling mill in the row of rolling mills You may

After controlling the rotation speed of all the rolling mills Ri of the row of rolling mills, rolling may be performed by fixing the rotation speed ratio of each rolling mill Ri.

The rolling speed of the rolling mill Rn on the most downstream side of the row of rolling mills may be increased to a desired speed while fixing the rotational speed ratio of each rolling mill Ri.

Further, according to the present invention from another viewpoint, a rolling mill train composed of at least 3 or more n rolling mills and a rolling mill or rolling mill train of at least one or more mills are arranged in this order in tandem. A production line of a section steel for reducing the pressure between the side surface of the horizontal roll and the circumferential surface of the cocoon roll with one or more rolling mills, and in the production line, an upstream row of rolling mills After the tension-free control of the material to be rolled is performed and the tension-free control is completed, the downstream rolling mill or rolling mill train has an upstream rolling mill row with a sufficient distance for the rolling material to bite A downstream rolling mill or rolling mill train is disposed, and the rolling mill method described above is implemented independently of the upstream rolling mill train and the downstream rolling mill or rolling mill train. A production line of shaped steel is provided.

Further, according to the present invention, there is provided a method of producing a shaped steel by reducing the pressure between the side surface of the horizontal roll and the circumferential surface of the scissor roll, comprising at least three or more n rolling mills. In a row of rolling mills, for each rolling mill Ri, after the material to be milled bites into the rolling mill Ri and before the material to be milled bites into the rolling mill Ri + 1 located downstream of the rolling mill Ri The rotation speed of the rolling mill Ri is fixed, the rolling torque Gi of the rolling mill Ri at that time is stored as Gi *, and after the material to be rolled bites into the rolling mill Rn on the most downstream side of the row of rolling mills The rolling torque Gn-1 of the rolling mill Rn-1 located upstream of the rolling mill Rn is stored as the rolling torque of the rolling mill Rn-1 before the material to be rolled bites into the rolling mill Rn. The rotation speed of the rolling mill Rn is equal to 1 * A first control process to control, and a rolling torque Gn ** of the rolling mill Rn after the first control process are stored, and then, rolling of a rolling mill Rn-2 located upstream of the rolling mill Rn-1 is performed. The rolling mill Rn-1 is such that the torque Gn-2 is equal to Gn-2 * stored as the rolling torque of the rolling mill Rn-2 before the material to be rolled bites into the rolling mill Rn-1. A second control step of controlling the rotational speed of the rolling mill Rn so as to control the rotational speed of the rolling mill Rn so that the rolling torque Gn of the rolling mill Rn becomes equal to the stored rolling torque Gn **. The second control step is applied to all the rolling mills Ri, and the rolling torque G1 of the most upstream rolling mill R1 is before the rolling mill R2 located downstream of the rolling mill R1 is engaged with the rolling mill R1. Equal to G1 * stored as rolling torque Characterized by producing a shape steel by controlling the rotational speeds of the rolling mill Ri of sea urchin the rolling mill train, the manufacturing method of the shaped steel is provided.

According to the present invention, when rolling a shaped steel by using a continuous rolling mill consisting of three or more rolling mills in a tandem state, even under such a condition that the distance between stands is short, each rolling condition With a simple control system that does not use table values etc., it becomes possible to control the tension between the stands with high accuracy, and to achieve stabilization of threading and improvement of product dimensional accuracy.

It is a schematic explanatory drawing about the manufacturing line of H section steel. It is a schematic explanatory drawing of a universal rolling mill and an edger rolling mill. It is the plane schematic of a rolling mill row which consists of three rolling mills R1-R2-R3. It is a schematic explanatory drawing regarding tension control in case distance between stands is long. It is a schematic explanatory drawing at the time of applying conventional tension control, when distance between stands is very short. It is a schematic explanatory drawing at the time of applying tension control concerning the present invention, when distance between stands is very short. FIG. 10 is a schematic explanatory view showing a combination of a rolling mill row consisting of rolling mills R1 to R3 in proximity and a rolling mill at a downstream position sufficiently separated from the rolling mill row. A schematic showing a combination of a rolling mill train comprising rolling mills R1 to R3 close to each other and a second rolling mill train comprising rolling mills R4 to R6 close to each other at a downstream position sufficiently separated from the rolling mill trains FIG. It is a schematic explanatory drawing of the universal intermediate | middle rolling of H section steel. It is the graph which showed the torque change amount of each stand when the tension between stands changes by numerical analysis.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and the drawings, components having substantially the same functional configuration will be assigned the same reference numerals and redundant description will be omitted. In this specification, as a rolling mill constituting a continuous rolling mill, a universal rolling mill and an edger rolling mill used when manufacturing an H-shaped steel product are illustrated as an example, but the scope of application of the present invention is It is not limited to this. Moreover, the "universal rolling mill" in this specification refers to a rolling mill that performs rolling with large stretching using a horizontal roll and a skewer roll at the time of shape steel rolling, and "edger rolling" in combination with the universal rolling mill It is intended to refer to rolling mills used for extremely light rolling, and in the present specification they are sometimes referred to as "rolling stands" or simply "stands".

(Outline of production line and conventional problems)
FIG. 1 is an explanatory view of a production line L on which the method of rolling a shaped steel according to the present embodiment is performed. As shown in FIG. 1, a heating furnace 2, rough rolling mills 4, two intermediate

universal rolling mills

5, 6, and a finishing universal rolling mill 8 are arranged in order from the upstream side in a production line L. Further, an edger rolling mill 9 is provided between the two intermediate

universal rolling mills

5 and 6. In the following, steel materials in the production line L may be collectively referred to as “rolled material S” for the sake of description, and the shapes thereof may be illustrated using broken lines, oblique lines, and the like as appropriate in each drawing.

As shown in FIG. 1, in the production line L, the material S to be rolled such as the slab 11 extracted from the heating furnace 2 is roughly rolled in the rough rolling mill 4. Then, the intermediate universal rolling is performed in the intermediate

universal rolling mills

5 and 6. Further, in a state in which the intermediate universal rolling and the reverse rolling are possible, the edger rolling machine 9 applies a pressure to the end portion (flanged portion 12) of the material to be rolled. In a normal case, approximately 4 to 6 hole types are engraved on the rolls of the rough rolling mill 4 (a plurality of machines may be installed), and reverse rolling of a plurality of passes is performed via these. The H-shaped rough section 13 in a dog bone shape is formed by using a rolling mill row comprising the first middle universal rolling mill 5-edger rolling machine 9-the second middle universal rolling mill 6 Thus, multiple passes of pressure are applied to shape the intermediate material 14. Then, the intermediate material 14 is finish-rolled into a product shape in a finish universal rolling mill 8 to produce an H-shaped steel product 16.

In the production line L shown in FIG. 1, the rolling mill row consisting of the first intermediate universal rolling mill 5-edger rolling mill 9-the second intermediate universal rolling mill 6 is used to reduce a plurality of passes with respect to the H-shaped rough section 13 When forming the intermediate material 14, as shown in FIG. 2 (a) in each universal rolling mill, the flange tip end is not pressed (refer to the broken line in the figure), so as shown in FIG. 2 (b). As shown, rolling is performed so as to shape and press the unreduced portion with an edger rolling mill.

The configuration of the first intermediate universal rolling mill 5-edger rolling mill 9-second intermediate universal rolling mill 6 as described above is an example of a continuous rolling mill row for rolling a material to be rolled in a tandem state. In a rolling mill row having a configuration in which a plurality of such rolling stands are continuously arranged, when rolling shaped steel as the material to be rolled S, since the rigidity of the material to be rolled is large, the looper used during steel strip rolling etc. It is difficult to control the tension between rolling stands using a (tension control device). In rolling of shaped steel, in order to prevent defects in passing of the material to be rolled between rolling stands and to ensure stable passing, tension between the stands tends to be pulled when biting. It is common to set to a certain rotation speed. That is, in order to maintain a good product size in rolling of shaped steel, it is required to suitably control the tension between the stands after the material is caught.

In addition, in the continuous rolling mill row, the distance between the stands of the plurality of stands may be shortened for energy saving, cost saving and downsizing of equipment. However, when performing tandem rolling of shaped steel, if the distance between stands is shortened, there is a risk that the material to be rolled may bite into the downstream stand before the distance between the upstream rolling stands is controlled to no tension. There is a possibility that the control such as pulling tension between the stands as usual may not be stable.
In view of such circumstances, in the continuous rolling mill row for tandem rolling of shaped steel, even if the distance between stands is short, the tension between the stands is controlled with high accuracy, the material passing is stabilized and the product dimensions There is a need for a technology that can improve the accuracy.

(Example of application of tension control method)
In the production line L shown in FIG. 1, the configuration of the first intermediate universal rolling mill 5-edger rolling mill 9-the second intermediate universal rolling mill 6 is described as the continuous rolling mill row (see FIG. 2), but the present invention The tension control method can be applied to any rolling mill as long as a plurality of rolling mills (stands) are continuously arranged in a facility that performs tandem rolling of shaped steel. Therefore, hereinafter, a conventional tension control method and a case where the tension control method according to the present invention is applied to a rolling mill train in which three stands of R1 to R3 are continuously arranged will be described as an example. The present configuration is an example, and the tension control method according to the present invention is applicable to a row of rolling mills in which at least three or more rolling mills are in a tandem rolling state.

FIG. 3 is a schematic plan view of the rolling mill row 30 consisting of three rolling mills R1-R2-R3. In the rolling mill row 30, for example, reverse rolling is performed as indicated by a broken arrow in the figure. . The distance between stands of three rolling mills (rolling stands) of R1, R2 and R3 is a distance shorter than the length in the longitudinal direction of the material S to be rolled, and so-called tandem rolling causes rolling of the material S to be rolled It will be. When the tension control method according to the present invention is applied, the distance between the stands is sufficiently short compared to the rolling speed of the material to be rolled S, that is, before being caught in the downstream stand. The advantage of the present invention over the prior art is exhibited when the tension between the stands can not be made non-tensioned. However, the present invention can be applied even at a long stand-to-stand distance to which, for example, Patent Document 2 (Japanese Patent Publication No. 53-34586) can be applied.

(Conventional tension control and its problems)
First, tension control in the case where the distance between the stands is sufficiently long in the rolling mill train 30 including three rolling mills R1-R2-R3 will be described. Here, the configuration “the distance between the stands is sufficiently long” indicates that no tension control of the material to be rolled S is performed between the stands and there is a sufficient distance for settling.

FIG. 4 is a schematic explanatory view related to tension control when the distance between stands is long, and is a schematic view showing a change in rolling torque (solid line) and a change in rotational speed (one-dot chain line) of each rolling mill R1 to R3. In the following, each rolling torque of R1 to R3 is defined as G1 to G3 as a value which changes with time, and each rolling torque value at a specific time point is described as an individual value such as "G1 *". In addition, the schematic about the position of the to-be-rolled material S in the situations A and B in the said schematic diagram (FIG. 4) is collectively described in FIG. The tension control in the case where the distance between the stands is long will be described with reference to FIG.

1) In the previous stage of the situation A shown in FIG. 4, the rolling torque G1 * of R1 is stored immediately before the material to be rolled S bites into R2. Then, in the situation A, after the material to be rolled S bites into R2, the rotational speed of R1 is controlled so that G1 = G1 *, and the R1-R2 section is brought into no tension state (static state), The rolling torque G2 * of R2 in the state is stored.
2) In the situation B shown in FIG. 4, after the material to be rolled S bites into R3, the rotational speed of R2 is controlled so that the rolling torque G2 of R2 becomes G2 = G2 *. As a result, both R1-R2 and R2-R3 are controlled to no tension.

Next, a case where the conventional tension control is applied in a configuration in which the distance between stands is extremely short in the rolling mill train 30 including three rolling mills R1-R2-R3 will be described. Here, “a configuration in which the distance between the stands is extremely short” indicates a configuration in which the material S to be rolled is caught in the downstream stand before the distance between the upstream rolling stands is controlled to be in a non-tension state.

FIG. 5 is a schematic explanatory view when the conventional tension control is applied when the distance between stands is extremely short, and shows the change in rolling torque (solid line) and the change in rotational speed (one-dot chain line) of each rolling mill R1 to R3. It is a schematic diagram. In addition, also in FIG. 5, the schematic about the position of the to-be-rolled material S in the situations A and B in the said schematic diagram (FIG. 5) is described collectively. A case where conventional tension control is applied in a configuration in which the distance between stands is extremely short will be described with reference to FIG.

1) In the previous stage of the situation A shown in FIG. 5, the rolling torque G1 * of R1 is stored immediately before the material to be rolled S bites into R2. Then, after the material to be rolled S bites into R2 in situation A, the rotation speed control of R1 is performed so that G1 = G1 *, but the material to be rolled S bites R3 before the control is completed. Be Even if the rolling torque G2 * of R2 is stored in this state, the stored G2 * is a value in a state in which the rear tension is applied.
2) Even if control is performed such that G2 = G2 * and G1 = G1 * in the situation B shown in FIG. 5, as described above, the stored G2 * is in a state where back tension is applied. Because of the value, the tension between R2 and R3 is not in a non tension state, and a suitable tension control is not realized.

As described above with reference to FIGS. 4 and 5, in the rolling mill train 30 including three rolling mills R1-R2-R3, when the distance between the stands is sufficiently long, the conventional tension control technology is used. Although suitable tension control is possible by application (refer to FIG. 4), there is a problem that the conventional tension control technology can not realize suitable tension control (refer to FIG. 5) in the configuration where the distance between stands is extremely short. Be

In view of the above-mentioned subject, when performing tension control in a rolling mill line which consists of a plurality of rolling mills, the present inventors rotate in the state (before the rolling material S gets caught in the downstream rolling mill) of the front tension 0. After fixing the number, after the material to be rolled S bites in all the rolling mills, a tension control method and a rolling method using it were devised, sequentially tracing back to make the inter-stand tension zero. Hereinafter, the rolling method according to the present invention will be described.

(Rolling method and tension control according to the present invention)
Here, the case where the tension control technique according to the present invention is applied to a configuration in which the distance between stands is extremely short in the rolling mill train 30 including three rolling mills R1-R2-R3 will be described. The tension control technology according to the present invention is applicable to the case where tandem rolling is performed in a rolling mill train configured by rolling mills of any n machines (n is an integer of 3 or more), and the description thereof For the sake of simplicity, the rolling mill train 30 comprising three rolling mills R1-R2-R3 will be described here.

FIG. 6 is a schematic explanatory view when the tension control according to the present invention is applied when the distance between stands is extremely short, and shows the rolling torque change (solid line) and rotational speed change (dashed dotted line) of each rolling mill R1 to R3. It is a schematic diagram shown. In FIG. 6, a schematic view of the position of the material to be rolled S in the situations A to C in the schematic view (FIG. 6) is also shown. The case where tension control according to the present invention is applied to a configuration in which the distance between stands is extremely short will be described with reference to FIG.

1) In the previous stage of the situation A shown in FIG. 6, the rolling torque G1 * of R1 is stored immediately before the material to be rolled S bites into R2.
2) In the situation A shown in FIG. 6, that is, immediately before the material S to be rolled bites into R3, the rolling torque G2 * of R2 is stored, and the rotational speed of R1 is fixed at this stage.
3) The situation B shown in FIG. 6, that is, after the material to be rolled S bites into R3, the rotation torque R2 is equal to the stored G2 * (G2 = G2 *), so that the rotation torque R2 Control the number. After controlled settling, no tension is applied between R2 and R3. The rolling torque G3 ** of R3 in this state is stored.
4) Between the situation B and the situation C shown in FIG. 6, control the number of revolutions of R2 so that G1 = G1 * (ie, no tension between R1 and R2). By controlling the number of rotations of R2 (changing the number of rotations), tension or compressive force acts between R2 and R3, but at that time, the number of rotations of R3 is set to maintain G3 = G3 **. Control.
5) In the situation C shown in FIG. 6, the rolling torque G2 ** of R2 at the time when the tension between R1-R2 and R2-R3 is settled is stored.
6) G1 *, G2 **, and G3 ** stored in the above process are rolling torques when the front / rear tension is 0, so G1 = G1 *, G2 = G2 **, G3 = By controlling the rotation speed of each rolling mill so as to be G3 **, the tension-free state can be maintained over the entire length of the rolling mill train.

As described above, by adopting the tension control method described in 1) to 6) with reference to FIG. 6 in tandem rolling in a row of rolling mills 30, between the rolling stands (between R1 and R2 and between R2 and R3) Tension control can be performed with high accuracy, and rolling can be performed while maintaining a non-tension state. As a result, the passability of the material to be rolled between the rolling stands is improved, and deterioration in dimensional accuracy, slippage, and sagging due to compressive force are prevented.

Further, in the present embodiment, without using table values and the like for each rolling condition, the measurable rolling torque is stored, and a simple control system is a tension over the entire length of the rolling mill train 30 consisting of R1-R2-R3. Control can be implemented with high accuracy.

(Application to an optional multi-roll mill train)
Although the case where the tension control according to the present invention is applied to the rolling mill train 30 consisting of three rolling mills R1-R2-R3 has been described above with reference to FIG. 6, the scope of application of the present invention is It is not limited. That is, the technique of the present invention is also applicable to a rolling mill train comprising three or more optional rolling mills. Hereinafter, a tension control method in the case where tandem rolling is performed in a rolling mill row consisting of three or more optional n rolling mills will be described. In the following, for the sake of explanation, each rolling mill constituting a rolling mill row consisting of n rolling mills is R1, R2,... Rn, and the i-th rolling mill among them is Ri, Ri. The rolling torque is defined as Gi. That is, i is an arbitrary integer of 1 to n, and n is an integer of 3 or more.

1) In rolling mills Ri other than the most downstream rolling mill Rn, after the material to be rolled bites into Ri, the rolling torque Gi * of Ri immediately before biting into the rolling mill Ri + 1 downstream is stored. Fix the rotation speed of.
2) After the material to be rolled bites into the most downstream rolling mill Rn, the rolling torque Gn-1 of the rolling mill Rn-1 immediately before the most downstream becomes the rolling torque Gn-1 * stored before Rn biting Thus, the rotation speed of the rolling mill Rn on the most downstream side is controlled (first control step). By this control, the tension state of Rn-1 becomes equal to the state immediately before the material to be rolled bites into the most downstream rolling mill Rn (forward tension = 0).
3) The rolling torque Gn ** of the rolling mill Rn after tension control stabilization in the first control step is stored.
4) The rolling torque Gn-2 of the rolling mill Rn-2 located upstream of the rolling mill Rn-1 is stored as the rolling torque of the rolling mill Rn-2 before the material to be rolled bites into the rolling mill Rn-1. The rotation speed of the rolling mill Rn-1 is controlled to be equal to Gn-2 *, and the rolling torque Gn of the rolling mill Rn maintains the rolling torque Gn ** stored in the above 3). The rotational speed of the rolling mill Rn is controlled (second control step). Here, the rolling torque Gn-1 ** of the rolling mill Rn-1 is stored after tension control settling.
5) Thereafter, in the same manner, the second control step is performed on each rolling mill so as to sequentially go back upstream. That is, for each rolling mill Rn-1, Rn-2, ... R1, the rolling torque Gi of the rolling mill immediately before the rolling mill becomes the rolling torque Gi * stored before the rolling mill bites into the rolling mill. So that the rolling torques Gi + 1 to Gn of the rolling mills Ri + 1 to Rn downstream of the rolling mills maintain the rolling torques Gi + 1 ** to Gn ** stored after tension settling. By controlling the rotational speed of Ri + 1 to Rn, the non-tensioned state can be realized similarly between the respective rolling mills after control.
6) Finally, the rolling torque G1 of the most upstream rolling mill R1 is equal to G1 * stored as the rolling torque of the rolling mill R1 before it bites into the rolling mill R2 located downstream of the rolling mill R1 The rotation speed of each rolling mill Ri of the row of rolling mills is controlled to be as follows.

The first control step in the above-described tension control method is a step of controlling the rotation speed of the rolling mill Rn so that Gn-1 = Gn-1 *, and is a single control step of Rn. In the second control step, the rotational speed of the rolling mill Ri is controlled so that Gi = Gi *, and Gk = Gk ** (k =) for the rolling mill Rk downstream of the rolling mill Ri. The interlock control step is to control the rotational speed so as to maintain i + 1 to n). By sequentially applying the second control process upstream from the rolling mill Rn-1, it is possible to control the tension state among all the rolling mills.

As described above, after the material to be rolled is caught in the most downstream rolling mill Rn, tension control is performed so as to trace back to the upstream one by one, and finally control is performed to the most upstream rolling mill R1. It is possible to carry out tension control such that each rolling mill is in a non-tensioned state for the entire train of machines.

Although the example of the embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is obvious that those skilled in the art can conceive of various modifications or alterations within the scope of the idea described in the claims, and they are naturally within the technical scope of the present invention. It is understood that.

In the rolling method according to the present invention described in the above embodiment, the temperature change at the time of rolling of the material to be rolled S is not particularly mentioned. However, when the size of the material to be rolled S is long in the longitudinal direction, the temperature of the material to be rolled S changes with time when performing tandem rolling in a rolling mill row consisting of a plurality of rolling mills such as R1-R2-R3. The rolling torque of each rolling mill may fluctuate with the temperature change. If the above-mentioned tension control method is applied without considering the fluctuation of the rolling torque due to the temperature change, an error associated with the fluctuation may occur.

In view of such circumstances, when applying the tension control technique described in the above embodiment, it is a value obtained by dividing the rolling torque (G) by the load (P) instead of the value of the rolling torque (G) A torque arm coefficient (G / P) may be used. By implementing the tension control method according to the present invention by using the torque arm coefficient (G / P) instead of the rolling torque, the influence of the rolling torque change accompanying the temperature change of the material to be rolled S is excluded, and the tension between the stands Control can be performed.

In addition, in the case where a tension-free state (static state) in a row of rolling mills is realized by the rolling method described in the above embodiment, the mill rigidity of the row of rolling mills is sufficiently large with respect to the temperature change. When the dimensional change of the total length of the train is small, the rotational speed ratio of each rolling mill in the stationary state may be fixed. For example, when it is desired to increase the rolling speed after the stationary state, it is necessary to increase the rolling speed of the entire rolling mill row. At that time, the non-tensioned state (statically determined state) can be maintained by performing acceleration in a state in which the fixed rotational speed ratio is kept as it is. At this time, the rolling speed of the other rolling mill is determined so that the above-mentioned rotational speed ratio becomes the same ratio according to the rolling speed of the most downstream rolling mill, with the most downstream rolling mill downstream of rolling being the desired speed. Just do it.

(Modification of the present invention)
FIG. 7 is a schematic explanatory view showing a combination of a rolling mill row 30 consisting of rolling mills (stands) R1 to R3 in close proximity and a rolling mill F1 at a downstream position sufficiently separated from the rolling mill row 30. In the configuration as shown in FIG. 7, in the rolling mill train consisting of R1 to R3, the tension control method described in the above embodiment is applied, the tension from R1 to R3 is settled, and then the material to be rolled is The rotational speed of F1 may be controlled so that the value of the rolling torque G3 of R3 becomes G3 = G3 ** (the rolling torque of R3 after settling) after S bites into F1. Thus, no tension can be established between R3 and F1.

8 shows a second row of rolling mills 30 including rolling mills R1 to R3 close to each other, and second rolling mills including rolling mills F1 to F3 close to each other at a downstream position sufficiently separated from the rolling mill row 30. FIG. 6 is a schematic explanatory view showing a combination with a train of machines 50. In the configuration as shown in FIG. 8, in the rolling mill train 30 consisting of R1 to R3, the tension control method described in the above embodiment is applied, and the tension from R1 to R3 is settled and F1 is rolled. Before the material S bites in, the rotational speed of R1 to R3 is fixed. In this manner, while the rotational speed of R1 to R3 is fixed, the tension control method described in the above embodiment is similarly applied to the second rolling mill group 50, and the tension state of F1 to F3 is stabilized. . And about tension control between rolling mill row 30 and the 2nd rolling mill row 50, it may control by arbitrary control methods, for example, G3 = G3 ** (rolling torque of R3 after settling) The rotational speed of F1 may be controlled to be

Carried out tandem rolling with a total rolling reduction of 40% and rolling speed at the rolling mill side of 4.0 m / s in four rolling mill trains (from the upstream R1 to R4) with a distance between rolling mills of 2.0 m. When doing this, the case where the tension between the stands was controlled by the present invention (Example) and the case where it was controlled using the prior art (Comparative Examples 1 and 2) was compared.
In Comparative Example 1, using the technology disclosed in Patent Document 2 (Japanese Patent Publication No. 53-34586) as the prior art, the rolling torque is stored 0.1 second before biting in the downstream stand, and after the downstream stand bites 0 After five seconds, the rotational speed was controlled so that the rolling torque had the value stored before the downstream stand bite. Here, the timing at which the rolling torque is stored is set 0.1 seconds before the biting of the downstream stand because the rolling speed is estimated from the distance between the stands and the roll speed, and the time to bite into the downstream stand of the material to be rolled In order to estimate, the estimation timing is added to prevent the storage timing of the rolling torque from being after the downstream stand bites. Also, 0.5 seconds after start of control at the downstream stand biting time is a time required to avoid a transient state such as recovery from a drop in rotation speed (impact drop) due to biting.
Further, in Comparative Example 2, using the technology disclosed in Patent Document 3 (Japanese Patent Publication No. 61-3564) as the prior art, calculation of the non-tension torque Gj0 of the stand is performed 0.1 seconds before biting in the downstream stand. After the material to be rolled bites into all the stands, control was performed so as to set the inter-stand tension to zero. Here, the calculation timing of the non-tension torque Gj0 is 0.1 seconds before biting in the downstream stand because the rolling speed is estimated from the distance between the stands and the roll speed, and the time to bite in the downstream stand of the material to be rolled The estimation timing is taken into consideration in order to estimate the following, so that the storage timing of the rolling torque will not be after the downstream stand bites.

In the case where the present invention was applied (Example), it was possible to perform rolling without any sagging on the material to be rolled. On the other hand, in Comparative Example 1, the time for performing tension control of R1-R2 takes only 0.07 seconds before storing the rolling torque of R2, and the rolling torque G1 of R1 is settled to the value stored before R2 is engaged. could not. Furthermore, for R3, the timing for storing the rolling torque overlapped with the transient state after biting, and bit R4 without controlling the tension between R2 and R3. As a result, a significant compressive force was generated between R3 and R4, and the material to be rolled was crushed between the stands.
In Comparative Example 2, although the steady part was rolled without any occurrence of rolling or the like, the rolling torque of R3 rapidly decreased immediately after the kicking of R2, and as a result, a control command to accelerate R3 was issued. Baking occurred in the material to be rolled between R4.

The present invention is applicable to, for example, a method of rolling a shaped steel for producing a shaped steel such as an H-shaped steel, a T-shaped steel, or an I-shaped steel, a production line of shaped steel and a method of manufacturing shaped steel.

2 ... heating furnace 4 ... rough rolling machine 5 ... (first) intermediate universal rolling machine (U1)
6 (Second) intermediate universal rolling mill (U2)
8: Finishing universal rolling machine 9: Edger rolling machine (E)
30 ... rolling mill row 50 ... second rolling mill row S ... material to be rolled L ... production line

Claims

In tandem rolling in a row of rolling mills composed of at least three or more n rolling mills, a shape steel that performs reduction between the horizontal roll side surface and the weir roll circumferential surface with one or more rolling mills Rolling method, and
For each rolling mill Ri of the row of rolling mills, after the material to be milled bites into the rolling mill Ri and before the material to be milled bites into the rolling mill Ri + 1 located downstream of the rolling mill Ri The rotation speed of the rolling mill Ri is fixed, and the rolling torque Gi of the rolling mill Ri at that time is stored as Gi *.
After the material to be rolled bites into the most downstream rolling mill Rn of the row of rolling mills, the rolling torque Gn-1 of the rolling mill Rn-1 located upstream of the rolling mill Rn is rolled to the rolling mill Rn Controlling the rotational speed of the rolling mill Rn so as to be equal to Gn-1 * stored as the rolling torque of the rolling mill Rn-1 before the metal bites;
The rolling torque Gn ** of the rolling mill Rn after the first control step is stored,
Next, the rolling torque Gn-2 of the rolling mill Rn-2 located upstream of the rolling mill Rn-1 is the rolling torque of the rolling mill Rn-2 before the material to be rolled bites into the rolling mill Rn-1. Control the rotational speed of the rolling mill Rn-1 to be equal to the stored Gn-2 *, and make the rolling torque Gn of the rolling mill Rn equal to the stored rolling torque Gn ** Control step of controlling the rotation speed of the rolling mill Rn
The second control process is applied to all the rolling mills Ri, and the rolling torque G1 of the top-most rolling mill R1 is rolled before the rolling mill R2 located before the rolling mill R2 located downstream of the rolling mill R1. A method of rolling a shaped steel, comprising controlling the rotational speed of each rolling mill Ri of the rolling mill row to be equal to G1 * stored as a torque.
However, i is an arbitrary integer of 1 to n, and n is an integer of 3 or more.
Control using the torque arm coefficient (G / P), which is a value obtained by dividing the rolling torque of each rolling mill by the rolling load of the rolling mill instead of the rolling torque value of each rolling mill in the row of rolling mills A method of rolling a section steel according to claim 1, characterized in that:
The section steel according to claim 1 or 2, characterized in that rolling is carried out by fixing the rotational speed ratio of each rolling mill Ri after controlling the rotational speed of all the rolling mills Ri of the row of rolling mills. Rolling method.
The section steel according to claim 3, wherein the rolling speed of the rolling mill Rn on the most downstream side of the row of rolling mills is increased to a desired speed while fixing the rotational speed ratio of each rolling mill Ri. Rolling method.
A rolling mill train comprising at least three or more n rolling mills and at least one or more rolling mills or rolling mill trains are arranged in tandem in this order, and one or more rolling mills It is a production line of shaped steel that performs pressure reduction between the horizontal roll side and the scissor roll peripheral surface,
In the production line, no tension control of the material to be rolled is performed in the upstream row of rolling mills, and after the non tension control is completed, a sufficient amount of the material to be rolled can be caught in the downstream rolling mill or rolling mill row. An upstream rolling mill row and a downstream rolling mill or rolling mill row are arranged at a distance,
The rolling mill method according to any one of claims 1 to 4 is characterized in that the upstream rolling mill train and the downstream rolling mill or rolling mill train are independently performed. , Shape steel production line.
A method for producing a shaped steel which is produced by applying a pressure between a horizontal roll side surface and a weir roll peripheral surface,
In a row of rolling mills composed of at least three or more n rolling mills, each rolling mill Ri is after the material to be rolled bites into the rolling mill Ri and downstream of the rolling mill Ri Before the material to be rolled bites into the positioned rolling mill Ri + 1, the rotational speed of the rolling mill Ri is fixed, and the rolling torque Gi of the rolling mill Ri at that time is stored as Gi *,
After the material to be rolled bites into the most downstream rolling mill Rn of the row of rolling mills, the rolling torque Gn-1 of the rolling mill Rn-1 located upstream of the rolling mill Rn is rolled to the rolling mill Rn Controlling the rotational speed of the rolling mill Rn so as to be equal to Gn-1 * stored as the rolling torque of the rolling mill Rn-1 before the metal bites;
The rolling torque Gn ** of the rolling mill Rn after the first control step is stored,
Next, the rolling torque Gn-2 of the rolling mill Rn-2 located upstream of the rolling mill Rn-1 is the rolling torque of the rolling mill Rn-2 before the material to be rolled bites into the rolling mill Rn-1. Control the rotational speed of the rolling mill Rn-1 to be equal to the stored Gn-2 *, and make the rolling torque Gn of the rolling mill Rn equal to the stored rolling torque Gn ** Control step of controlling the rotation speed of the rolling mill Rn
The second control process is applied to all the rolling mills Ri, and the rolling torque G1 of the top-most rolling mill R1 is rolled before the rolling mill R2 located before the rolling mill R2 located downstream of the rolling mill R1. A manufacturing method of a section steel, characterized by manufacturing a section steel by controlling the number of rotations of each rolling mill Ri of the row of rolling mills to be equal to G1 * stored as a torque.