JP5361454B2 - Hot hole rolling method and hot hole rolling equipment for strip steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of surface flaws in a method for hot-caliber-rolling bar steel. <P>SOLUTION: This method for hot-caliber-rolling the bar steel is a method for hot-rolling by the calibers by which a rolled stock 2 is hot-rolled by rolling with square-caliber rolling rolls 9 after rolling with diamond-caliber rolling rolls 9 and a lubricant 15 is supplied to the rolled stock 2 on the upstream side of the inlet side of the square-caliber rolling rolls 9. Furthermore, preferably, it is better to measure the angle &theta; of twist of the rolled stock 2 on the outlet side of the diamond-caliber rolling rolls 9, to adjust the feed rate of the lubricant 15 on the basis of the measured angle &theta; of twist and to feed the lubricant 15 when the angle &theta; of twist is &ge; 3&deg;. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  TECHNICAL FIELD The present invention relates to a hot hole rolling method and hot hole rolling equipment for a steel bar that hot-rolls steel bars such as wire rods and bar steels with good surface quality.

Steel bars such as wire rods and bar steels are manufactured by continuously rolling a rolled material (original material) such as a billet. Such rolling equipment for rolling steel bars includes a heating furnace for heating the rolled material in order from the upstream side, a plurality of rough rolling mills, intermediate rolling mills, finish rolling mills, and a winder for winding the steel bars. The steel strip is manufactured by gradually rolling the rolled material along the longitudinal direction with a plurality of rolling mills.
By the way, a caliber (hole type) is formed for each rolling mill on the rolling rolls of the plurality of rolling mills. There are square hole type, rhombus type, oval hole type, round hole type, etc. in the cross-sectional shape of this caliber. When a set of rolling rolls are brought into contact with each other, a caliber is formed between these rolling rolls. It has become. The strip rolling equipment is provided with a plurality of rolling mills having different caliber shapes. For example, the rolling material is removed from each rolling mill while changing the cross-sectional shape such as a rhombus type, a square hole type, and a rhombus type. Steel bars are manufactured by passing through the caliber in order.

  However, when rolling the steel bar, the temperature distribution in the rolled material is not uniform in the cross section, and the rolled material after rolling may be twisted. Especially when rolling material twisted on the exit side of the rhomboid-type rolling roll is to be rolled continuously with the square-hole-type rolling roll, the cross-sectional shape of the caliber is greatly different, so when entering the square-hole-type rolling roll, The rolled material may be folded at a corner part of a square hole type (for example, the top part of the square hole type). As described above, since the folded portion remains as a surface flaw on the steel bar, it is difficult to obtain a steel bar having excellent surface quality with a rolling facility continuously provided with a rhombus type and a square hole type rolling roll.

Therefore, in order to suppress the occurrence of such surface flaws, for example, a pair of guide rollers are rotatably installed on the entrance side of a square hole type rolling mill, and the rolling material is sandwiched between the pair of guide rollers and twisted. Patent Document 1 discloses a rolling method for rolling while straightening. In the rolling method of Patent Document 1, when twisting occurs in the rolled material, the guide roller is rotated in a direction opposite to the twisting direction of the rolled material, so that rolling can be performed while correcting the twist.
Further, Patent Document 2 discloses a rolling method in which the position of the hole mold is adjusted by shifting the rolling rolls in the axial direction, and the rolled material is rolled while correcting the twist.

JP 2000-176529 A JP 2007-290006 A

However, in the method of rolling while sandwiching the rolled material with the guide roller as in Patent Document 1, there is a possibility that the rolled material may come into strong contact with the guide roller, and surface flaws are generated instead of the rolled material due to contact with the guide roller. There is a fear. In addition, if the guide roller is used to forcibly correct a rolled material with a large twist, the bearing and the roller guide itself may be damaged and the guide roller and the rolled material may be seized, or the twist of the rolled material may not be eliminated. There is also.
On the other hand, in the rolling method of Patent Document 2, if either the upper or lower rolling roll is shifted in the roll axis direction and moved to the position where the hole shape is offset, the twist of the rolled material is reduced, but the rolled material has an asymmetric shape. There is a possibility that surface flaws are likely to occur after the next rolling stand.

For this reason, the conventional rolling method cannot reliably prevent surface flaws generated in the rolled material.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a hot hole rolling method and hot hole rolling equipment for steel bars that can reliably prevent surface flaws.

In order to achieve the object, the present invention takes the following technical means.
That is, the hot hole rolling method of the strip of the present invention is a hot hole rolling method in which a rolled material is hot rolled by rolling with a rhombus type rolling roll and then rolling with a square hole type rolling roll. The lubricant is supplied to the rolled material on the upstream side of the entrance side of the square hole type rolling roll.
In this way, if lubricant is supplied to the rolled material on the upstream side from the entrance side of the square hole type rolling roll, even if the rolled material is twisted after rolling with the rhombus type rolling roll, the rolled material is square hole type. It can be smoothly passed through the rolling rolls and surface flaws can be reliably prevented.

Preferably, the twist angle of the rolled material is measured on the exit side of the rhombus type rolling roll, and the supply amount of the lubricant is adjusted based on the measured twist angle.
In this way, the torsion angle of the rolled material rolled by the rhombus type rolling roll can be measured in real time, and the torsion of the rolled material is immediately corrected according to the torsion angle, so that from the beginning of winding. Stable steel with no surface defects until the end of winding can be produced stably.
Preferably, the lubricant is supplied when the twist angle becomes 3 degrees or more.
The most preferable form of the hot hole rolling method according to the present invention is a hot hole mold in which a rolled material is hot rolled by rolling with a square hole type rolling roll after rolling with a rhombus type rolling roll. In the rolling method, when the lubricant is supplied to the rolling material upstream from the entrance side of the square hole type rolling roll, the twist angle of the rolling material is set at the exit side of the rhombus type rolling roll. It measures and adjusts the supply amount of the lubricant based on the measured twist angle.

Further, the hot-hole rolling equipment for strips according to the present invention includes a rhombus type rolling roll for rolling a rolled material, and a square hole type rolling roll for rolling the rolled material following the rhomboid-type rolling roll. A hot-hole rolling facility for steel bars provided with a lubricant supply section that supplies lubricant to the rolled material on the upstream side from the entrance side of the square-hole type rolling roll. It is what.
Preferably, the hot hole type rolling equipment is based on a measurement unit that measures a twist angle of the rolled material on the exit side of the rhomboid-type rolling roll, and the twist angle measured by the measurement unit. It is good to provide the control part which controls the supply amount of the lubricant supplied by the lubricant supply part.

The controller may be configured to supply the lubricant when the twist angle becomes 3 degrees or more.
Further, the most preferable form of the hot hole type rolling equipment according to the present invention is a rhombus type rolling roll for rolling the rolled material, and a square hole type for rolling the rolled material following the rhomboid type rolling roll. A hot hole rolling facility for strip steel comprising a rolling roll, and a lubricant supply section for supplying a lubricant to the rolled material upstream from an inlet side of the square hole type rolling roll; A measurement unit that measures the twist angle of the rolled material on the exit side of the hole-type rolling roll, and a supply amount of lubricant that is supplied by the lubricant supply unit based on the twist angle measured by the measurement unit. And a control unit for controlling.

  Surface flaws can be reliably prevented by the hot-drilling rolling method and hot-drilling rolling equipment of the strip of the present invention.

It is an arrangement plan of rolling equipment of the present invention. It is explanatory drawing which shows the mesh in the cross-sectional direction of the rolling material used for FEM analysis. It is explanatory drawing which shows the mesh in the rolling direction of the rolling material used for FEM analysis. It is a figure which shows the relationship between the friction coefficient (micro | micron | mu) at the time of rolling, and the twist recovery rate calculated | required by FEM analysis. It is an enlarged view of the A section of FIG. It is the result of the experimental example which compared the relationship between the twist angle and the surface flaw occurrence rate with and without lubrication.

Hereinafter, the hot hole rolling method and hot hole rolling equipment of the strip of the present invention will be described below.
FIG. 1 shows a hot hole rolling facility (hereinafter simply referred to as a rolling facility 1) of the strip of the present invention. The rolling equipment 1 is a rolling production line for continuously rolling a rolled material 2 made of a steel material such as a billet to produce a strip steel. A heating furnace 3 and a descaler 4 for heating the rolled material 2 from the upstream side toward the downstream side. The rough rolling mill row 5, the intermediate rolling mill row 6, the finish rolling mill row 7, and the winder 8 are arranged in order.
In the following description, the left side of FIG. 1 is the upstream side when describing the rolling equipment 1 and the rolling method, the right side of FIG. 1 is the downstream side, and the direction from the upstream side to the downstream side is the rolling equipment 1 and the rolling method. It is set as the rolling direction when explaining. Further, the upper and lower sides in FIG. 1 are the upper and lower sides when describing the rolling equipment 1 and the rolling method, and the right and left sides in the rolling direction are the right and left sides when explaining the rolling equipment 1 and the rolling method.

The heating furnace 3 is an apparatus for heating the rolled material 2 to about 1000 to 1200 ° C., and the rolled material 2 heated in the heating furnace 3 is sent to the descaler 4. The descaler 4 is a device that removes the subscale formed on the surface of the rolled material 2 after heating with the action of water vapor, spraying high-pressure washing water, or a mechanical brush. Rolling with the subscale removed by the descaler 4 The material 2 is sent to the rough rolling machine row 5.
The rough rolling mill row 5, the intermediate rolling mill row 6, and the finish rolling mill row 7 are provided with a plurality of rolling stands 10 provided with a pair of rolling rolls 9 and 9, and these rolling stands 10 are rolling rolls. 9 is provided in various directions so that the cross section of the rolled material 2 is changed to a corner, an ellipse, a circle, etc. while repeating rolling from various angles such as a horizontal direction and a vertical direction. Reduced and rolled.

The rough rolling mill row 5 and the intermediate rolling mill row 6 include a vertical rolling stand 10V provided with a vertical rolling roll 9V provided with an axis oriented in the vertical direction, and a horizontal rolling provided with an axis oriented in the horizontal direction. Horizontal rolling stands 10H provided with rolls 9H are alternately provided along the rolling direction. In the present embodiment, the rough rolling mill row 5 has four horizontal rolling stands 10H and three vertical rolling stands 10V, and the intermediate rolling mill row 6 has four horizontal rolling stands 10H and four vertical rolling stands, respectively. It has a rolling stand 10V.
Each of the rolling stands 10 constituting the horizontal rolling stand 10H and the vertical rolling stand 10V has a pair of rolling rolls 9 and 9 formed in a cylindrical shape or a columnar shape, and between the pair of rolling rolls 9 and 9. The rolled material 2 can be rolled by sandwiching the rolled material 2. Grooves are formed on the outer circumferential surfaces of the pair of rolling rolls 9 and 9 in the circumferential direction, and these grooves are joined together when the pair of rolling rolls 9 and 9 are brought into contact with each other. A caliber 11 (hole type) is formed between 9 and 9. The caliber 11 is formed so as to have a larger cross-sectional area as the rolling stand 10 provided on the upstream side. By reducing the cross-sectional area of the caliber 11 through which the rolled material 2 passes, the rolled material is reduced. Rolling is performed while gradually moving 2 to a desired diameter and cross-sectional shape.

  The caliber 11 of the rolling stand 10 has a cross-sectional shape such as a rhombus type (diamond), a square hole type (square), an elliptical hole type (oval), or a round hole type (round). The rolling stands 10 having these shapes are used in combination in accordance with the material or the type and application of the steel bar. For example, the rough rolling mill row 5 is composed of a rolling stand 10 having a rhombus-horn series caliber 11 of rhombus → rhom → rhom → corner → rhom → horn → rhombic, and the intermediate rolling mill row 6 is an oval. It comprises a rolling stand 10 equipped with an oval-round series caliber 11 of oval → oval → oval → round → round → round → round.

  The finish rolling mill row 7 includes two rollings: a block mill 12 (VBM) disposed on the downstream side of the intermediate rolling mill row 6 and a sizing mill 13 (RSM) disposed on the downstream side of the block mill 12. It consists of a series of machines. The block mill 12 and the sizing mill 13 are provided with a horizontal rolling roll 9H, a vertical rolling roll 9V, and an inclined rolling roll 9S (for example, a rolling roll arranged so that its axis is inclined at 45 ° from a horizontal plane) in the rolling direction. A plurality of combinations are arranged along the line, and the final adjustment is performed according to product specifications for the rolled material 2 rolled by the intermediate rolling mill row 6.

The winder 8 is arranged on the downstream side of the finish rolling machine row 7, and the steel strip finally rolled in the finish rolling machine row 7 in the winder 8 (the rolled material 2 after the final rolling is referred to as a steel bar). The same applies hereinafter) is wound in a ring shape.
By the way, when rolling the rolled material 2, the temperature distribution in the rolled material 2 is not uniform within the cross section of the rolled material 2, so that the rolled material 2 after the rolling is twisted (is generated around an axis that faces the rolling direction). Twisting of the rolled material 2 may occur. As in the case of the rough rolling mill row 5 described above, the rolled material 2 is twisted particularly on the exit side of the rhombus type rolling stand 10 (rolling roll 9), and the twisted rolled material 2 is continuously used as the square hole type. When passing through the rolling stand 10, the cross-sectional shape of the caliber 11 is greatly different, so that the rolled material 2 is broken at the corner portion (for example, the top portion of the square hole type) when entering the square hole type roll 9. There is a risk that the folded portion may remain as a surface flaw on the steel bar.

Therefore, the present inventors supply a lubricant 15 to the rolling material 2 entering the square hole type rolling roll 9, and the friction coefficient μ between the rolling material 2 and the surface of the rolling roll 9 (the surface in the caliber 11). Therefore, it was considered that the twist of the rolled material 2 was recovered when entering the square hole type caliber 11 and the rolled material 2 was properly bitten into the square hole type caliber 11.
First, whether this idea is correct is verified by performing a simulation analysis using a finite element method (FEM).
As shown in FIG. 2, when the analysis is performed by the finite element method, it is necessary to divide the rolled material 2 that is going to enter the caliber 11 of the square hole type roll 9 into a plurality of elements. About the cross-sectional direction of the rolling material 2, the rolling material 2 was divided | segmented into the some element according to the mesh 16 into which a corner part is divided into 4 parts, a linear part (surface part) is divided into 6 parts, and a radial direction is divided into 8 parts. Further, as shown in FIG. 3, along the rolling direction, the entrance side (upstream side of the square hole type rolling roll 9) is divided into 8 parts, inside the roll bit (under the square hole type rolling roll 9). The rolled material 2 was divided into a plurality of elements in accordance with a mesh 16 in which 10 is divided into 10 and the exit side (downstream side of the square hole type roll 9) is divided into 5 parts. When each of the elements of the mesh 16 has a friction coefficient μ between the rolling roll 9 and the rolled material 2 of 0.3, 0.4, 0.5, or 0.6, a square hole The degree of torsion recovery obtained on the exit side of the rolling stand 10 of the mold was analyzed by simulation using a rigid plastic three-dimensional FEM model (developed by the present inventors).

Incidentally, twist recovery rate in the central portion in the lateral direction of the rolled material 2, the exit side from the inlet side of the twist angle theta _in the rolling roll 9 to the rolling roll 9 of the square hole type and a twist angle theta _out respectively measured at the location shown in FIG. 4, the twist angle theta _in, the theta _out was calculated by substituting the equation (1).
Twist recovery rate (%) = (θ _in −θ _out ) / θ _in × 100 (1)
As shown in FIG. 4, it can be seen that the torsional recovery rate increases by reducing the friction coefficient μ from 0.6 to 0.3. From this, supplying the lubricant 15 to the rolled material 2 to reduce the friction coefficient μ between the rolled material 2 and the surface of the rolling roll 9 is to twist the rolled material 2 when entering the square hole type caliber 11. A sufficient effect can be expected to recover the surface and suppress the generation of surface defects. Therefore, the present inventor makes it possible to supply the lubricant 15 to the rolled material 2 by configuring the rolling equipment 1 as shown below.

As shown in FIG. 5, the rolling equipment 1 of the present invention lubricates the rolled material 2 with a measuring unit 18 that measures the twist angle θ of the rolled material 2 on the upstream side from the exit side of the rhomboid-type rolling roll 9. A lubricant supply unit 19 that supplies the lubricant 15 and a control unit 20 that adjusts the supply amount of the lubricant 15 supplied by the lubricant supply unit 19 based on the twist angle θ measured by the measurement unit 18 are provided. .
The measuring unit 18 includes a projector that projects slit light from the periphery of the rolled material 2 toward the surface of the rolled material 2, and an imaging device that images reflected light of the slit light projected from the projector. A plurality of sets are provided around the periphery of the steel sheet, and the shape of the rolled material 2 during high-speed movement and the rolled material 2 during torsional vibration can be accurately measured.

  The measuring unit 18 is arranged on the exit side of the rhombus-type rolling roll 9, and is configured to measure the twist angle θ with respect to the rolled material 2 coming out of the rhombus-type rolling roll 9. The position where the measuring unit 18 is disposed is the exit side of the rhombus-type rolling roll 9, that is, the vicinity of the exit side of the rhombus-type rolling roll 9 as shown in FIG. A rhombus type rolling roll 9 side) from an intermediate position with the hole type rolling roll 9 is preferable. As the position at which the twist angle θ of the rolled material 2 is measured is closer to the rhombus-type rolling roll 9, the twist of the rolled material 2 generated on the exit side of the rhomboid-type rolling roll 9 is quickly captured and corrected. This is because it becomes possible. The twist angle θ of the rolled material 2 measured by the measuring unit 18 is output to the control unit 20.

The measuring unit 18 is not necessarily provided in the vicinity of the exit side of the rhomboid-type rolling roll 9, but is applied to the rolling material 2 to which the lubricant 15 is supplied from the lubricant supply unit 19 described later. On the other hand, since it is not preferable to measure the torsion angle θ, it is preferable that the measuring unit 18 is provided between the rhombus type rolling roll 9 and the lubricant supply unit 19.
As shown in FIG. 5C, the twist angle θ of the rolled material 2 measured by the measuring unit 18 is when there is no twist (when the rolled material 2 goes straight into the square hole type roll 9 without being twisted). It is shown by how much the cross section of the rolled material 2 rotates around the axis centered on the basis of the above. In the illustrated example, a rolled material 2 rolled into a rhombic cross section by a rhombus type rolling roll 9 is rotated (twisted) clockwise around the axis by a twist angle θ of the rolled material 2. Is measured by the measuring unit 18.

The control unit 20 gives an instruction (signal) of the supply amount of the lubricant 15 to the lubricant supply unit 19 based on the twist angle θ of the rolled material 2 measured by the measurement unit 18, for example, a process computer or a sequencer Etc.
In the control unit 20, the supply amount of the lubricant 15 corresponding to the twist angle θ of the rolled material 2 is determined in advance, and the lubricant supply unit 19 is adjusted to the predetermined supply amount. In the control unit 20 of the present embodiment, the lubricant 15 is not supplied when the twist angle θ is less than 3 °, and the lubricant 15 is supplied only when the twist angle θ is 3 °. Yes. The supply amount of the lubricant 15 is gradually increased as the twist angle θ becomes larger than 3 °.

On the other hand, it is known that the upper limit of the twist angle θ of the rolled material 2 is about 30 ° based on operation results. The present inventors have confirmed the twist correction effect of the lubricant 15 until the twist angle θ is 30 °.
The lubricant supply unit 19 includes a pipe 21 that supplies the lubricant 15 and a valve 22 provided in the pipe 21. The base end of the pipe 21 is connected to a lubricating oil tank or the like (not shown), and the tip opens toward the upstream side of the rolling roll 9 while facing the caliber 11. Further, the valve 22 can be opened and closed in accordance with an instruction from the control unit 20, and the supply amount of the lubricant 15 flowing through the pipe 21 can be freely adjusted.

As the lubricant 15 supplied from the lubricant supply unit 19, it is possible to use a lubricating oil in which a synthetic ester, an oil improver, an anti-seizure extreme pressure agent or the like is added to a mineral oil as a base oil. The position for supplying the lubricant 15 from the lubricant supply unit 19 may be anywhere as long as it is upstream of the square hole type roll 9 to be lubricated, but it is in contact with the rolled material 2 heated to a high temperature. Considering that the lubricant 15 evaporates, it is preferably between the rhombus type rolling roll 9 and the square hole type rolling roll 9, particularly preferably immediately before the square hole type rolling roll 9. .
Next, the content of the control performed by the control unit 20, in other words, the hot hole rolling method for the strip of the present invention will be described.

  The rolled material 2 is first heated to about 1000 to 1200 ° C. in the heating furnace 3, then the subscale is removed by the descaler 4, and sent to the rough rolling mill row 5. In the rough rolling mill row 5, a plurality of rolling stands 10 each having a caliber 11 of any one of a rhombus type, a square hole type, an oval hole type, and a round hole type move the cross-sectional area of the caliber 11 to the downstream side. It is deployed to be small. Therefore, the rolled material 2 sent to the rough rolling mill row 5 is rolled while gradually approaching a desired diameter and cross-sectional shape through a plurality of rolling stands 10. Then, the rolled material 2 is rolled into a strip and rolled up by a winder 8 by sequentially rolling in an intermediate rolling mill row 6 and a finishing rolling mill row 7 having a plurality of rolling stands 10 similar to the rough rolling mill row 5. It is wound up.

  At this time, when the rolled material 2 is rolled by the square hole type roll 9 following the rhombus type roll 9, the rolled material 2 is rolled by the measuring unit 18 provided on the exit side of the rhomboid type roll 9. The twist angle θ of the material 2 is measured. The measured twist angle θ is output to the control unit 20. The control unit 20 first determines whether or not the twist angle θ is 3 ° or more. When the twist angle θ is 3 ° or more, a predetermined supply amount is determined according to the value of the twist angle θ. A lubricant 15 supply instruction (signal) is output to the lubricant supplier 19. When the twist angle θ is less than 3 °, the supply instruction is not output. In the lubricant supply unit 19, the valve 22 is opened and closed in accordance with a supply instruction input from the control unit 20, and the lubricant is supplied immediately before the square hole type roll 9.

  In this way, the friction coefficient μ between the rolled material 2 and the surface of the rolling roll 9 (the surface in the caliber 11) is reduced, and the twist of the rolled material 2 is recovered when entering the square hole type caliber 11. The rolled material 2 is properly bitten into the square hole type caliber 11. As a result, the rolled material 2 is not folded, and the folded portion is prevented from remaining and becoming a surface defect.

Next, the hot hole rolling method of the strip of the present invention will be described using examples and comparative examples.
Examples and Comparative Examples are a plurality of rolling stands equipped with rhombus-square series calibers after heating a 155 mm square steel material to a required rolling temperature using an experimental machine obtained by simplifying the actual machine shown in FIG. Rolled. In this experimental machine, a rolling stand provided with a rhombus type caliber is provided on the upstream side, and a rolling stand provided with a square hole type caliber is provided adjacent to the downstream side of the rolling stand. .
As shown in FIG. 3, in the example, the twist angle θ of the rolled material 2 is measured on the exit side of the rolling roll of the rolling stand provided with the rhombus type caliber, and the measured twist angle θ is 3 °. In the above case, the lubricant 15 is supplied to the rolled material 2 via the roll bite from the entrance side of the rolling stand provided with the square hole type caliber, and when the twist angle θ is less than 3 ° Rolling was performed without using the lubricant 15. In the comparative example, rolling was performed in this experimental machine without supplying the lubricant 15.

In the case of the examples and comparative examples, the surface flaw occurrence rate of 0.02 mm or more generated in the bar steel when the twist angle θ of the rolled material 2 was changed was examined. The results are shown in FIG.
From FIG. 6, it can be seen that when the twist angle θ is up to 3 °, the surface flaw occurrence rate is low at less than 0.5% in both the example and the comparative example, and the lubricant if the twist angle θ is less than 3 degrees. It can be seen that the supply of 15 is not necessary.
On the other hand, when the result of the twist angle θ of 3 ° or more is seen, the surface flaw occurrence rate of the example is maintained below 0.5%, whereas the surface flaw occurrence rate of the comparative example has a larger helix angle θ. It grows as you go.

From the above, when the twist angle θ is 3 ° or more, it is determined that the example in which the lubricant 15 is supplied can suppress the generation of surface flaws than the comparative example in which the lubricant 15 is not used.
The present invention is not limited to the above-described embodiments, and the shape, structure, material, combination, and the like of each member can be appropriately changed without changing the essence of the invention.
In the said embodiment, the rolling equipment 1 which supplies the lubricant 15 in the rough rolling mill row | line | column 5 in which the rolling stand 10 of a rhombus type | mold and a square hole type | mold was provided side by side was illustrated. However, the supply of the lubricant 15 is not limited to the rough rolling mill row 5. For example, in the rolling mill 1 in which the rhombus type and the square hole type rolling stands 10 are provided side by side in the intermediate rolling mill row 6 and the finishing rolling mill row 7, the lubricant 15 is supplied to either of them. May be.

  In the above embodiment, the example in which the lubricant 15 is not supplied when the twist angle θ is less than 3 ° has been described. However, the method of supplying the lubricant 15 according to the twist angle θ is limited to the above embodiment. is not. For example, the supply amount of the lubricant 15 can be changed linearly or nonlinearly according to the twist angle θ.

1 Rolling equipment (hot hole type rolling equipment)
DESCRIPTION OF SYMBOLS 2 Rolled material 3 Heating furnace 4 Descaler 5 Rough rolling mill row 6 Intermediate rolling mill row 7 Finish rolling mill row 8 Winding machine 9 Rolling roll 9H Horizontal rolling roll 9S Inclined rolling roll 9V Vertical rolling roll 10 Rolling stand 10H Horizontal rolling stand 10V Vertical rolling stand 11 Kariba 12 Block mill 13 Sizing mill 15 Lubricant 16 Mesh 18 Measuring unit 19 Lubricant supply unit 20 Control unit 21 Piping 22 Valve θ Torsion angle θ In side torsion angle θ _in square hole type rolling roll θ _out Outward twist angle from square hole type rolls μ Friction coefficient

Claims (4)

A hot hole rolling method for hot rolling a rolled material by rolling with a square hole type rolling roll after rolling with a rhombus type rolling roll,
When supplying a lubricant to the rolling material on the upstream side from the entrance side of the square hole type rolling roll ,
Hot hole rolling of strip steel, characterized in that the twist angle of the rolled material is measured on the exit side of the rhomboid-type rolling roll, and the supply amount of the lubricant is adjusted based on the measured twist angle. Method. Wherein when the twist angle becomes 3 times or more, hot caliber rolling method long products according to claim 1, wherein the supplying the lubricant. A hot-hole rolling facility for steel bars comprising a rhomboid-type rolling roll for rolling a rolled material, and a square-hole-type rolling roll for rolling the rolled material following the rhomboid-type rolling roll. ,
A lubricant supply section for supplying a lubricant to the rolled material on the upstream side from the entrance side of the square hole type rolling roll ;
A measurement unit that measures the twist angle of the rolled material on the exit side of the rhomboid-type rolling roll, and supply of lubricant that is supplied by the lubricant supply unit based on the twist angle measured by the measurement unit And a hot-rolling rolling facility for steel bars, characterized by comprising a control unit for controlling the amount . The hot-rolling rolling equipment for steel bars according to claim 3 , wherein the controller supplies the lubricant when the twist angle becomes 3 degrees or more.

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