CN112139265A

CN112139265A - Steel cooling device

Info

Publication number: CN112139265A
Application number: CN202010585231.9A
Authority: CN
Inventors: 高木启次
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2019-06-28
Filing date: 2020-06-24
Publication date: 2020-12-29
Anticipated expiration: 2040-06-24
Also published as: CN213256296U; JPWO2020261547A1; CN112139265B; JP7006846B2; WO2020261547A1

Abstract

The steel product cooling facility has a first cooling device and a second cooling device, and the first cooling device is provided with: a linear cooling pipe through which steel passes; a cooling box formed on a part of the outer periphery of the cooling pipe; and a spray slit for spraying the cooling water accumulated in the cooling tank to the steel material from the entire inner peripheral region of the cooling pipe, wherein the cooling pipe is formed with a roller insertion hole penetrating the cooling pipe in the thickness direction, a part of a support roller supported rotatably on the outside of the cooling pipe is disposed so as to protrude into the cooling pipe through the roller insertion hole, the support roller supports the lower part of the steel material passing through the inside of the cooling pipe, and the second cooling device does not have the support roller and the roller insertion hole with respect to the first cooling device. The plurality of first cooling devices and the plurality of second cooling devices are arranged in series with a predetermined gap provided therebetween along the traveling direction of the steel material, the second cooling devices are arranged in series between adjacent first cooling devices, and the interval between adjacent first cooling devices is set to a value equal to or less than 80 times the diameter of the cooling pipe.

Description

Steel cooling device

Technical Field

The present invention relates to a steel material cooling apparatus for cooling an elongated steel material such as a steel bar or a wire rod.

Background

In a hot rolling facility including a plurality of rolling mills (roughing mill, intermediate rolling mill, finishing mill) for producing a long steel product such as a bar or a wire rod, a steel product cooling facility for cooling the steel product is disposed between a predetermined pair of rolling mills or at a rear stage of the finishing mill.

For example, patent document 1 discloses a steel material cooling facility in which a plurality of cooling devices are arranged in series at predetermined intervals along the traveling direction of a steel material to be cooled.

The cooling device of patent document 1 includes a linear cooling pipe through which a steel material passes and a cooling water injection nozzle that injects cooling water into the cooling pipe, and the cooling water injection nozzle includes a cooling tank formed on a part of the outer periphery of the cooling pipe and an injection slit that injects the cooling water accumulated in the cooling tank from the entire inner periphery of the cooling pipe. When the steel material inserted from the insertion opening of the steel material cooling facility passes through the cooling pipe interior of each cooling device, the steel material is continuously cooled by the cooling water sprayed from the cooling water spray nozzles of each cooling device.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-123354

Disclosure of Invention

Problems to be solved by the invention

However, the steel material passing through the inside of the cooling pipe of each cooling device of the steel material cooling facility may be deflected downward by the weight of the steel material and pass through the lower side of the inside of the cooling pipe. In the technique described in patent document 1, the cooling water is sprayed from the entire inner circumferential area of the cooling pipe through the spray slits in order to uniformly supply the cooling water over the entire circumference of the steel material and to avoid uneven cooling in the circumferential direction of the steel material. However, if the steel material passes through the lower side of the cooling pipe while being deviated from the axial center thereof, the cooling capacity of the cooling water sprayed from the spray slits may be uneven in the circumferential direction of the steel material, which may result in uneven cooling. Further, if the steel material in the cooling pipe is deflected downward by its own weight and comes into contact with the lower inner wall of the cooling pipe, the quality may be affected.

The present invention has been made in view of the unsolved problems of the conventional examples, and an object thereof is to provide a steel material cooling facility capable of cooling a steel material with high quality by eliminating uneven cooling.

Means for solving the problems

In order to achieve the above object, a steel material cooling facility according to an aspect of the present invention cools an elongated steel material such as a steel bar or a wire rod rolled by a hot rolling facility, the steel material cooling facility including: a linear cooling pipe through which the steel material passes; a cooling box formed on a part of the outer periphery of the cooling pipe; and a spray slit for spraying the cooling water stored in the cooling tank to the steel material from the entire inner peripheral region of the cooling pipe, wherein the cooling pipe is formed with a roller insertion hole penetrating the cooling pipe in the thickness direction, a part of a support roller supported rotatably outside the cooling pipe is disposed so as to protrude into the cooling pipe through the roller insertion hole, and the support roller supports the lower portion of the steel material passing through the cooling pipe.

Effects of the invention

According to the steel material cooling facility of the present invention, since the support rollers provided in the cooling pipe suppress the steel material from moving to the lower side of the cooling pipe due to its own weight, the steel material can be cooled with high quality by eliminating the cooling unevenness.

Drawings

Fig. 1 is a schematic configuration diagram of a steel product cooling facility according to a first embodiment provided at a rear stage of a finishing mill of a hot rolling facility according to the present invention.

Fig. 2 is a view showing a steel material cooling facility of a steel material according to a first embodiment.

Fig. 3 shows a cooling device with a roll (first cooling device) used in the steel material cooling facility shown in fig. 2, in which a support roll is provided in a cooling pipe.

Fig. 4 shows a non-roll cooling device (second cooling device) used in the steel material cooling facility shown in fig. 2, in which no support roll is provided in the cooling pipe.

FIG. 5 is a schematic configuration diagram of a steel product cooling facility according to a second embodiment provided at a later stage of a roughing mill of the hot rolling facility according to the present invention.

Fig. 6 is a schematic configuration diagram of a steel product cooling facility according to a third embodiment provided at a later stage of an intermediate rolling mill of a hot rolling facility according to the present invention.

Description of the reference symbols

1 Hot Rolling plant

2 roughing mill

3 intermediate rolling mill

4 finishing mill

5 Steel cooling device

6. 6A, 6B, 6C with roller Cooling device (first Cooling device)

7 Rollerless Cooling device (second Cooling device)

8a bottom plate

8b water outlet

8 drainage tray

9 first water supply pipe

9a, 10a fixing part

10 second water supply pipe

11 cooling tube

11a inlet

11b outlet

12 cooling water injection nozzle

13 suspended part

13a engaging hole

14 fixing joint part

15 roller inserting hole

16 bearing part

17 support roller

18 rotating shaft

19 Ring case

20 supply port

21 jet slit

D reference interval between adjacent cooling devices with rollers

L clearance between a pair of cooling devices

SM steel

Inner diameter of Pd cooling pipe

Detailed Description

Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar reference numerals are given to the same or similar parts. It should be noted, however, that the drawings are schematic, and the relationship of the thickness to the planar size, the ratio of the thicknesses of the respective layers, and the like are different from reality. Therefore, specific thickness and size should be determined by referring to the following description. It is to be understood that the drawings also include portions having different dimensional relationships and ratios.

The embodiments described below exemplify apparatuses and methods for embodying the technical ideas of the present invention, and the technical ideas of the present invention do not specify the materials, shapes, structures, arrangements, and the like of the constituent members as follows. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

As shown in fig. 1, a hot rolling facility 1 for hot rolling a rolling material RM such as a general steel, an alloy steel, or a stainless steel to produce, for example, a long steel SM having a circular cross section includes a roughing mill 2, an intermediate rolling mill 3, and a finishing mill 4, and a steel cooling facility 5 according to a first embodiment of the present invention disposed at a subsequent stage of the finishing mill 4.

In the steel material cooling facility 5 of the first embodiment, as shown in fig. 2, a plurality of cooling devices are arranged in series at predetermined intervals along the traveling direction of the steel material SM. In the present embodiment, 13 cooling devices are arranged in series, and the 13 cooling devices are constituted by 2 types of first cooling devices 6 and second cooling devices 7 described later.

The steel material cooling facility 5 includes a gutter-shaped drain pan 8 extending in the traveling direction of the steel material SM so as to surround the lower side of 13 cooling devices (the plurality of first cooling devices 6 and second cooling devices 7) and having a bottom plate 8a inclined downward toward the drain port 8b, and first and second

water supply pipes

9 and 10 extending in the longitudinal direction inside the drain pan 8 and connected to the 13 cooling devices.

Fig. 3 specifically shows the first cooling device 6 among the plurality of cooling devices arranged in series along the traveling direction of the steel material SM.

The first cooling device 6 is made of cast iron or cast steel, and includes a cooling pipe 11 and a cooling water injection nozzle 12.

The cooling pipe 11 is a cylindrical member extending linearly, and has one end opening 11a formed in an expanded diameter shape expanding in diameter toward an end portion as an inlet port (hereinafter, referred to as an inlet port 11a) of the steel material SM and the other end opening 11b as an outlet port (hereinafter, referred to as an outlet port 11b) of the steel material SM.

Here, the diameter Md of the steel SM passing through the inside of the cooling pipe 11 is set to 30% or less of the inner diameter Pd of the cooling pipe 11.

A suspended portion 13 having an engagement hole 13a in which a hook of a suspending tool can be engaged is formed to protrude upward from the upper outer periphery of the cooling pipe 11.

A fixed connection portion 14 fixed by bolt fastening to a fixing portion 9a (10a) rising from the upper outer periphery of the first water supply pipe 9 (or the second water supply pipe 10) is formed on the lower outer periphery of the cooling pipe 11.

A roller insertion hole 15 penetrating in the thickness direction is formed in the lower portion of the cooling pipe 11, and a bearing portion 16 is formed on the outer periphery of the lower portion of the cooling pipe 11 around the roller insertion hole 15.

A part of the backup roller 17 is inserted into the roller insertion hole 15 from the outside of the cooling pipe 11. The support roller 17 is coaxially fixed to a rotary shaft 18, and the rotary shaft 18 is rotatably supported by a bearing (not shown) provided in the bearing portion 16. The rotary shaft 18 is horizontally disposed below the axis P of the cooling pipe 11, and the axis P is orthogonal to the rotary shaft 18 when viewed from above.

The backup roll 17 is a ceramic roll, and the roll surface in contact with the steel material SM is formed in a shape in which a concave curved surface having a radius of curvature larger than the diameter of the steel material SM is formed along the axial direction of the rotating shaft 18 or a shape in which a surface opened in a V-shape along the axial direction at an angle of approximately 120 °.

The cooling water spray nozzle 12 includes an annular tank 19 formed to surround the outer periphery of the cooling pipe 11 on the outlet 11b side, a supply port 20 for supplying cooling water to the annular tank 19, and a spray slit 21 for spraying the cooling water accumulated in the annular tank 19 from the entire inner periphery of the cooling pipe 11. The supply port 20 of the cooling water spray nozzle 12 is connected to either one of the first and second

water supply pipes

9 and 10. The injection slit 21 is formed in a conical surface shape so that the injection direction of the cooling water is inclined toward the opening portion (inlet port of the steel SM) 11a side.

The first cooling device 6 is fixed to the upper portion of the first water supply pipe 9 (or the second water supply pipe 10) by the fixing portion 9a (10a) of the first water supply pipe 9 (or the second water supply pipe 10) via the fixing connection portion 14 of the cooling pipe 11.

Next, fig. 4 specifically shows the second cooling device 7 among the plurality of cooling devices arranged in series along the traveling direction of the steel material SM.

The second cooling device 7 is different from the first cooling device 6 in that the roller insertion hole 15, the bearing portion 16, and the support roller 17 formed in the cooling pipe 11 of the first cooling device 6 are not present in the cooling pipe 11 of the second cooling device 7.

The second cooling device 7 and the first cooling device 6 have the same other structures in terms of size, shape, and the like.

Here, the first cooling device 6 is referred to as a band roller cooling device 6, and the second cooling device 7 is referred to as a non-roller cooling device 7.

In the steel material cooling facility 5 shown in fig. 2, 3 cooling devices for strip rolls 6 are arranged in total at the positions of the fourth station (the device indicated by reference numeral 6A) from the leftmost side to the right side, the ninth station (the device indicated by reference numeral 6B) from the leftmost side to the right side, and the rightmost side (the device indicated by reference numeral 6C).

In the steel material cooling facility 5 shown in fig. 2, 3 cooling apparatuses are disposed on the left side of the first cooling apparatus 6A, 4 cooling apparatuses are disposed between the belt roll cooling apparatus 6A and the belt

roll cooling apparatus

6B, 3 cooling apparatuses are disposed between the belt roll cooling apparatus 6B and the belt

roll cooling apparatus

6C, and 10 cooling apparatuses are disposed in total.

Further, 13 belt

roll cooling devices

6A, 6B, and 6C and the non-roll cooling device 7 are arranged in series so as to be spaced apart from the adjacent cooling devices by a distance L of 10mm to 50 mm.

Here, the distance K1 between the adjacent belt

roller cooling devices

6A, 6B and the distance K2 between the adjacent belt

roller cooling devices

6B, 6C are set to be equal to or less than the reference distance D of the belt

roller cooling devices

6A, 6B, 6C (or the non-roller cooling device 7), the reference distance D being 80 times the inner diameter Pd of the cooling pipe 11 (D Pd × 80, K1 ≦ D, K2 ≦ D).

Next, the operation of the steel product cooling facility 5 of the first embodiment will be described.

When the cooling water is supplied to the first and second

water supply pipes

9 and 10 of the steel material cooling facility 5, the cooling water is accumulated in the annular tank 19 from the supply ports 20 of the plurality of

roll coolers

6A, 6B, and 6C and the non-roll cooler 7, and the cooling water in the annular tank 19 is ejected from the entire inner peripheral area of the cooling pipe 11 through the ejection slit 21.

The steel SM finish-rolled by the finish rolling mill 4 and sent out to the steel cooling facility 5 passes through the inlet ports 11a and the outlet ports 11B of the cooling pipes 11 of the plurality of

roll cooling devices

6A, 6B, and 6C and the non-roll cooling device 7 arranged in series along the traveling direction of the steel SM, and is gradually cooled by contact with the cooling water sprayed from the entire inner circumference area of each cooling pipe 11. Since the injection slit 21 is provided so that the injection direction of the cooling water is inclined toward the inlet port 11a side, the cooling water injected from the injection slit 21 flows toward the inlet port 11a side in the cooling pipe after colliding with the steel material SM. The space between the inner peripheral surface of the cooling pipe 11 and the steel material SM is filled with cooling water, and the steel material SM is cooled while the cooling water in the cooling pipe 11 flows toward the inlet port 11 a.

Most of the cooling water that has increased in temperature and decreased in cooling capacity by contacting the steel material SM flows through the inlet port 11a of the cooling pipe 11, and a part of the cooling water flows through the outlet port 11B and the roller insertion hole 15 toward the bottom plate 8a of the drain pan 8, and is collected from the drain port 8B in the roll-to-

roll cooling devices

6A, 6B, and 6C. In the non-roll cooling device 7, most of the cooling water that has contacted the steel material SM flows through the inlet 11a of the cooling pipe 11 and partially flows toward the bottom plate 8a and the drain port 8b of the drain pan 8 through the outlet 11 b.

Here, in the case where all of the cooling devices arranged in series in the steel material cooling facility 5 in the conveying direction of the steel material SM are the non-roll cooling devices 7, the steel material SM conveyed from the finishing mill 4 may be deflected downward in the steel material cooling facility 5 by its own weight, and the steel material SM may pass through the lower side in the cooling passage (cooling pipe 11) of the steel material cooling facility 5. If the steel material SM passes through the cooling device 7 while being deflected downward in the cooling pipe 11, the cooling device 7 cannot uniformly cool the steel material in the circumferential direction. Further, when the steel material SM in the cooling pipe 11 is biased downward, the steel material SM may come into contact with the inner periphery of the cooling pipe 11, and a flaw may be generated on the surface of the steel material SM.

In the steel material cooling facility 5 of the present embodiment, 3 strip

roller cooling devices

6A, 6B, and 6C are arranged among a plurality of cooling devices arranged in series in the traveling direction of the steel material SM, and the support rollers 17 of these strip

roller cooling devices

6A, 6B, and 6C support the lower portion of the steel material SM by coming into contact with the lower side of the steel material SM passing through the cooling pipe 11, thereby preventing the steel material SM from passing through the lower side of the cooling pipe 11 due to its own weight. Although the backup roll 17 is in contact with the steel material SM, since the backup roll rotates along with the movement of the steel material SM, flaws are hardly generated in the steel material SM compared with the case of being in contact with the inner surface of the cooling pipe 11.

In the steel material cooling facility 5 of the present embodiment, all of the cooling devices arranged in series in the traveling direction of the steel material SM are not defined as the roll-to-

roll cooling devices

6A, 6B, and 6C, and the steel material SM is prevented from passing under the cooling pipe 11 due to its own weight by arranging only a small number of the roll-to-

roll cooling devices

6A, 6B, and 6C so that the interval between the adjacent roll-to-

roll cooling devices

6A and 6B (or the interval between the adjacent roll-to-

roll cooling devices

6B and 6C) is equal to or less than the reference interval D that is 80 times the inner diameter Pd of the cooling pipe 11 of the roll-to-

roll cooling device

6A, 6B, and 6C (or the non-roll cooling device 7).

Next, effects of the steel material cooling facility 5 of the first embodiment will be described.

Since the cooling water accumulated in the annular tank 19 of the cooling water injection nozzle 12 of each

cooling device

6A, 6B, 6C, 7 is injected from the entire inner peripheral region of the cooling pipe 11 through the injection slit 21 toward the steel material SM passing through the plurality of roll-equipped

cooling devices

6A, 6B, 6C of the steel material cooling facility 5 and the cooling pipe 11 of the non-roll cooling device 7, the steel material SM can be efficiently cooled.

Further, if a downward deflection due to its own weight occurs in the steel material SM sent out from the finishing mill 4 and the steel material SM passes below the cooling passage of the steel material cooling facility 5 due to the deflection, the distance between the injection slit 21 from which the cooling water is injected and the steel material SM varies greatly depending on the circumferential position of the steel material SM, and therefore, cooling unevenness along the circumferential direction of the steel material SM may occur. Further, if the steel material SM contacts the lower inner wall of the cooling passage (cooling pipe 11), the quality of the steel material SM may be adversely affected.

In this embodiment, the backup rolls 17 of the 3 belt

roll cooling devices

6A, 6B, and 6C are in contact with the lower side of the steel material SM passing through the cooling pipe 11, and thereby the steel material SM can be prevented from passing through the lower side of the cooling pipe 11. Thus, uneven cooling can be prevented. Further, the steel SM is prevented from contacting the lower inner wall of the cooling pipe 11, and the quality of the steel SM is not adversely affected.

Further, in the steel material cooling facility 5, the plurality of cooling devices arranged in series along the traveling direction of the steel material SM can prevent the steel material SM from passing under the cooling pipe 11 due to its own weight by simply arranging a small number of the

roll cooling devices

6A, 6B, and 6C so that the interval between the adjacent

roll cooling devices

6A and 6B (or the interval between the adjacent

roll cooling devices

6B and 6C) becomes equal to or less than the reference interval D that is 80 times the inner diameter Pd of the cooling pipe 11, and therefore, the facility cost of the steel material cooling facility 5 can be reduced.

Here, from the viewpoint of preventing the steel material SM from passing through the lower side in the cooling pipe 11 due to the deflection of the steel material SM caused by its own weight, it is conceivable to set all of the plurality of cooling devices arranged in series in the traveling direction as the non-roller cooling devices 7 and set the interval L between the adjacent non-roller cooling devices 7 to a large interval enough to arrange the support rollers 17. However, if the interval L is made large, the steel material SM is not cooled while passing through the position of the interval L. As described above, the interval L between the adjacent cooling apparatuses is provided to discharge the cooling water having the lowered cooling capacity, and may be a length enough to discharge the cooling water, and the smaller the interval L, the higher the cooling capacity per unit length of the cooling equipment can be, and more specifically, may be 10 to 50 mm.

By using some of the plurality of cooling devices arranged in series in the traveling direction as the belt roll cooling device 6 as in the present embodiment, the cooling capacity as the cooling device can be ensured by setting the interval L between the

adjacent cooling devices

6 or 7 small, and the steel material SM can be prevented from passing through the lower side in the cooling pipe.

Further, the steel material SM sent out from the finishing mill 4 to the steel material cooling facility 5 vibrates less than the steel material SM after the rough rolling process in the rough rolling mill 2 or the steel material SM after the intermediate rolling process in the intermediate rolling mill 3, and does not apply a large impact force to the backup rolls 17 of the

roll cooling devices

6A, 6B, and 6C, so that the use of the ceramic backup rolls 17 makes it possible to use the

roll cooling devices

6A, 6B, and 6C for a long period of time as the backup rolls 17 having excellent heat resistance and wear resistance are used.

Further, in the plurality of roll-to-

roll cooling devices

6A, 6B, 6C and the non-roll cooling device 7 constituting the steel material cooling facility 5, since the suspended portion 13 provided with the engaging hole 13a is formed in the cooling pipe 11, when a predetermined replacement operation of the cooling device is performed, the fixed state of the fixed connecting portion 14 of the cooling pipe 11 and the fixed portion 9a (10a) of the first water supply pipe 9 (or the second water supply pipe 10) is released, and the hook of the suspending member (the suspending device) is engaged with the engaging hole 13a of the suspended portion 13, so that the replacement operation can be easily performed.

Next, fig. 5 shows a steel material cooling facility 5 according to a second embodiment of the present invention disposed at a rear stage of the roughing mill 2 of the hot rolling facility 1.

In the steel material cooling facility 5 of the second embodiment, 3 belt

roller cooling devices

6A, 6B, 6C, and 10 non-roller cooling devices 7 are arranged in the same order as in fig. 2.

The steel material cooling facility 5 of the present embodiment is different from the first embodiment in that the backup rolls 17 disposed in the cooling pipes 11 of the 3 strip

roll cooling devices

6A, 6B, 6C are formed of cast iron or cast steel rolls.

The steel SM sent out from the roughing mill 2 to the steel cooling facility 5 vibrates greatly, and a large impact force is applied to the backup rolls 17 of the strip

roll cooling devices

6A, 6B, 6C. Therefore, by using the backup roll 17 made of cast iron or cast steel, the strip

roll cooling devices

6A, 6B, and 6C can be used for a long period of time by using the backup roll 17 having excellent impact resistance, heat resistance, and wear resistance.

Further, fig. 6 shows a steel cooling facility 5 according to a third embodiment of the present invention disposed at a rear stage of the intermediate rolling mill 3 of the hot rolling facility 1.

The steel material cooling facility 5 of the third embodiment is also provided with 3 belt

roller cooling devices

6A, 6B, 6C and 10 non-roller cooling devices 7 in the same arrangement order as in fig. 2.

The steel material cooling facility 5 of the present embodiment is different from the first and second embodiments in that the backup rolls 17 disposed in the cooling pipes 11 of the 3 belt

roll cooling devices

6A, 6B, 6C are formed of rolls made of cemented carbide (tungsten carbide).

The steel SM sent out from the intermediate rolling mill 3 to the steel cooling facility 5 is not sent out from the roughing mill 2, but the vibration is relatively large, and an impact force is applied to the backup rolls 17 of the strip

roll cooling devices

6A, 6B, 6C. Therefore, by using the backup roll 17 made of cemented carbide, the strip

roll cooling devices

6A, 6B, and 6C can be used for a long period of time by using the backup roll 17 excellent in impact resistance, heat resistance, and wear resistance.

Further, another roller (herein, referred to as a restraining roller) that suppresses, by contact, the steel material SM passing through the inside of the cooling pipe 11 from meandering in a direction (for example, a left-right direction and an upper direction) orthogonal to the traveling direction of the steel material SM may be provided in the plurality of roll-to-

roll cooling devices

6A, 6B, and 6C constituting the steel material cooling facility 5. Similarly, another binding roller that suppresses the steel material SM from meandering in a direction orthogonal to the traveling direction of the steel material SM by contact may be provided inside the cooling pipe 11 of the non-roller cooling device 7. The binding roller is also disposed so as to protrude into the cooling pipe through a binding roller insertion hole formed in the cooling pipe in the thickness direction, similarly to the support roller.

Examples

Next, the steel material cooling facility of the present invention and the steel material cooling facility of the comparative example different from the present invention were compared with respect to the cooling capacity of the steel material SM sent out from the finishing mill 4, the quality of the cooled steel material SM, and the like.

First, in the steel product cooling facility of the present invention, similarly to the steel product cooling facility 5 of fig. 2, the roll cooling device 6A is disposed on the fourth stage from the leftmost side to the right side of fig. 2, the roll cooling device 6B is disposed on the ninth stage from the leftmost side to the right side, and the roll cooling device 6C is disposed at the rightmost position (total of 3 roll cooling devices). As shown in fig. 2, 3 of the non-roller cooling devices 7 are disposed between the leftmost side and the first cooling device 6A, 4 are disposed between the belt roller cooling device 6A and the belt

roller cooling device

6B, 3 are disposed between the belt roller cooling device 6B and the belt

roller cooling device

6C, and 10 are disposed in total.

Further, the inner diameter Pd of the cooling pipe 11 constituting the

cooling devices

6A, 6B, 6C with rollers and the cooling device 7 without rollers is 48 mm. The diameter Md of the steel material SM fed out from the finishing mill 4 is 24 mm. Thus, the inner diameter Pd of the cooling pipe 11 is designed to exceed 30% of the diameter Md of the steel SM.

The steel material SM passed through the cooling pipes 11 of the belt

roller cooling devices

6A, 6B, and 6C and the non-roller cooling device 7 at a speed of 10 m/sec.

The interval K1 between the adjacent belt

roller cooling devices

6A and 6B is set to 1820mm, and the interval K2 between the adjacent belt

roller cooling devices

6B and 6C is set to 1390 mm. Since the inner diameter Pd of the cooling pipe 11 is 48mm, the intervals K1 and K2 are set to be equal to or less than 3840mm, which is a reference interval D80 times the inner diameter Pd.

On the other hand, in the steel material cooling facility of the comparative example, the non-roller cooling devices 7 are disposed instead of the positions where the belt

roller cooling devices

6A, 6B, and 6C are disposed in the steel material cooling facility 5 of fig. 2, and all of the 13 non-roller cooling devices 7 are disposed. The other arrangement positions and structures are the same as those of the steel material cooling facility of the present invention.

Next, the results of cooling the steel SM delivered from the finishing mill 4 at 900 ℃ by the steel cooling facility of the present invention and the steel cooling facility of the comparative example will be described.

In the steel material cooling facility of the present invention, the cooling water stored in the annular tank 19 of the cooling water spray nozzles 12 of the

cooling devices

6A, 6B, 6C, and 7 was sprayed from the entire inner peripheral region of the cooling pipe 11 through the spray slit 21 to the steel material SM passing through the cooling pipe 11 of the 3 belt

roller cooling devices

6A, 6B, and 6C and the non-roller cooling device 7, and it was confirmed that the steel material SM was cooled to approximately 800 ℃.

It was also confirmed that the steel material SM after passing through the steel material cooling facility of the present invention did not cause uneven cooling, and no damage or the like caused by contact with the inner wall of the cooling pipe 11 occurred on the outer periphery or the like.

On the other hand, in the steel material cooling facility of the comparative example, it was also confirmed that the cooling water stored in the annular tank 19 of the cooling water injection nozzle 12 of each cooling device 7 was injected from the entire inner peripheral region of the cooling pipe 11 to the steel material SM passing through the cooling pipes 11 of the 13 roll-less cooling devices 7 through the injection slit 21, and the steel material SM was cooled to approximately 800 ℃.

However, it was confirmed that the steel SM passed through the steel cooling facility of the comparative example had cooling unevenness, and damage or the like occurred on the outer periphery or the like due to contact with the inner wall of the cooling pipe 11. This is because the steel material SM fed from the finish rolling mill 4 is deflected, the steel material SM passes under the cooling pipes 11 of the cooling devices 7, and the distance between the injection slit 21, through which the cooling water is injected, and the steel material SM varies greatly depending on the circumferential position of the steel material SM, and therefore, cooling unevenness occurs along the circumferential direction of the steel material SM. Further, the steel material SM contacts the lower inner wall of the cooling pipe 11, and the outer periphery of the steel material SM is damaged.

Claims

1. A steel material cooling facility for cooling long steel materials such as bar steel and wire rod rolled by a hot rolling facility,

having a first cooling device and a second cooling device,

the first cooling device includes:

a linear cooling pipe through which the steel material passes;

a cooling box formed on a part of the outer periphery of the cooling pipe; and

a spray slit for spraying the cooling water accumulated in the cooling tank to the steel material from the entire inner peripheral region of the cooling pipe,

the cooling pipe is formed with a roller insertion hole penetrating the wall thickness direction,

a part of a support roller rotatably supported outside the cooling pipe is disposed so as to protrude into the cooling pipe through the roller insertion hole, and the support roller supports a lower portion of the steel material passing through the cooling pipe,

the second cooling device does not have the backup roller and the roller insertion hole with respect to the first cooling device,

the plurality of first cooling devices and the plurality of second cooling devices are arranged in series with a predetermined gap provided therebetween along the traveling direction of the steel material,

the second cooling device is disposed in series between the adjacent first cooling devices, and the interval between the adjacent first cooling devices is set to a value equal to or less than 80 times the diameter of the cooling pipe.

2. The steel product cooling apparatus according to claim 1,

wherein 1 or more of the plurality of first cooling devices and the plurality of second cooling devices include a restraint roller that restrains the movement of the steel material in the cooling pipe in at least one direction orthogonal to the traveling direction,

a part of the binding roller is arranged to protrude into the cooling pipe through a binding roller insertion hole formed in the cooling pipe so as to penetrate in the thickness direction.

3. The steel product cooling apparatus according to claim 1 or 2,

the diameter of the steel material is set to 30% or less of the inner diameter of the cooling pipe.

4. The steel product cooling apparatus according to any one of claims 1 to 3,

the cooling pipe is provided with a suspended part which can be engaged by a hoisting device.

5. The steel product cooling apparatus according to any one of claims 1 to 4,

the steel cooling apparatus is disposed between a roughing mill and an intermediate mill constituting the hot rolling apparatus,

the supporting roller is made of cast iron or cast steel.

6. The steel product cooling apparatus according to any one of claims 1 to 4,

the steel cooling apparatus is disposed between an intermediate rolling mill and a finishing mill constituting the hot rolling apparatus,

the supporting roller is made of superhard alloy.