JP4752252B2 - H-shaped steel cooling method - Google Patents

Description

The present invention relates to a cooling method for H-section steel, and more particularly to a cooling method for H-section steel in which cooling water is injected to cool a steel material .

During hot rough rolling or hot finish rolling of steel, when water cooling of steel is performed during or after rolling, laminar cooling that pours rod-like or film-like cooling water on the steel surface, spray that sprays mist-like cooling water Cooling is common.
When flat plate steel such as thick plates is spray cooled, spray nozzles are provided above and below the surface to be cooled (hereinafter referred to as “cooling surface”), and a center line (hereinafter referred to as “injection direction”) for injecting cooling water is provided. The nozzle layout is generally perpendicular to the cooling surface.

On the other hand, in the case of spray cooling a steel material having a three-dimensional shape such as a steel pipe or H-shaped steel, the injection direction is not necessarily perpendicular to the cooling surface. For this reason, a difference (so-called “cooling unevenness”) occurs in the cooling performance between the range close to the cooling nozzle and the range far from the cooling nozzle, and the steel material quality after cooling may become uneven depending on the position. In particular, in the range far from the cooling nozzle, there is a problem that the strength is insufficient due to insufficient cooling and the quality is deteriorated.
And in order to make up for such a lack of strength, a strengthening element such as Mn, Si, V, Nb or the like has to be added, which necessitates an increase in cost.

Then, in order to reduce the said cooling nonuniformity when spray-cooling the flange inner surface of H-section steel, the following invention is disclosed.
(A) Invention in which a plurality of rows of spray cooling nozzles are arranged (see, for example, Patent Document 1),
(B) The invention which makes the injection angle of cooling water variable (for example, refer patent document 2).

JP 52-104451 A (page 3, FIG. 6) JP-A-9-10819 (page 3, FIG. 1)

However, the inventions disclosed in Patent Documents 1 and 2 have the following problems.
(A) Since the number of spray cooling nozzles and the number of cooling nozzle heads increase, the manufacturing cost increases.
(B-1) Since variable means for making the injection angle variable is required, the manufacturing cost increases.
(B-2) Moreover, since it is necessary to carry out maintenance inspection of the movable part exposed to splashed water, a maintenance cost becomes high.

The present invention is intended to solve the above-described problems, and an object of the present invention is to provide a method for cooling an H-shaped steel that can reduce cooling unevenness without increasing the number of spray cooling nozzles.

(1) cooling method H-shaped steel of the present invention, the cooling zone of the hot rolling line to form a H-shaped steel is steel, is low position and conveying the apex of the conveying roller for conveying the H-beams At both positions higher than the flange height of the H-shaped steel, a discharge hole formed in the tip surface, a first flow path for pouring cooling water into the discharge hole, and a flow rate of the first flow path A cooling nozzle having a second flow path for pouring cooling water into the discharge hole with a small flow rate so that the first flow path side is closer to the flange inner surface of the H-shaped steel than the second flow path side Inclining to the inner surface of the flange,
Injecting cooling water from the cooling nozzle toward the flange inner surface of the H-shaped steel ;
A flange outer surface cooling section comprising a plurality of water storage chambers partitioned by a plurality of partition walls and a number of cooling water outflow holes drilled in one wall surface of the water storage chamber, the wall surface transporting the H-shaped steel Arranging to function as a guide for
Forming a laminar flow with a predetermined flow rate from the cooling water outflow hole;
Have
The surface temperature of the outer surface of the flange of the H-shaped steel is within the range of 580 to 660 ° C. when reheated after passing through the cooling zone.

(2) In (1), the flow passage cross-sectional area of the first flow path of the cooling nozzle is 2 to 4 times the flow passage cross-sectional area of the second flow path of the cooling nozzle. It is characterized by.

(3) In the above (1) or (2), the central axis of the tip section of the cooling nozzle is inclined by 30 to 75 ° with respect to the surface of the flange inner surface of the H-shaped steel.

(4) In any one of the above (1) to (3), the flange outer surface cooling section and the cooling nozzle are installed in a movable carriage that can advance and retreat in the width direction of the hot rolling line, and the movable carriage is Depending on the web width of the H-section steel, the flange outer surface and the flange inner surface of the H-section steel are cooled respectively.

According to the present invention, since the cooling water ejected from the discharge hole is increased on the second flow path side, it is possible to supply a larger amount of cooling water toward a range where there is a concern about insufficient cooling. , Cooling unevenness is reduced.
At this time, the cooling nozzle remains fixed, and it is not necessary to increase the quantity. Therefore, the apparatus is simple, and the manufacturing cost and maintenance cost are not increased.

(Cooling nozzle)
FIG. 1 schematically shows a cooling nozzle used in a method for cooling an H-section steel according to an embodiment of the present invention, wherein (a) is a rear view, (b) is a sectional view in side view, ) Is a front view.
In FIG. 1, the cooling nozzle 10 includes a discharge hole 4 formed in the distal end surface 5 of the rod-shaped main body 6, a first flow path 1 poured into the discharge hole 4, and a cross-sectional area of the first flow path 1. And a second channel 2 that pours into the discharge hole 4 with a smaller channel cross-sectional area. At this time, the first flow path 1 and the second flow path 2 merge at the merge portion 3 on the rear surface side (same as the main body side) of the discharge hole 4.
The rear end surface 7 of the main body 6 has inflow holes for the first flow path 1 and the second flow path 2.
The virtual plane 9 including the center of the main body 6 (same as the plane including the position “b”, the position “b”, the position “c”, and the position “d” in the drawing) is referred to as “injection center plane 9”. In the figure, it is indicated by a two-dot chain line. Accordingly, the discharge hole 4 has a slit shape (groove shape) and is formed so as to include a part of the injection center plane 9 (corresponding to being located in the injection center plane 9 with a predetermined thickness). ).

  Therefore, when cooling water having a predetermined water pressure is supplied to each of the first flow path 1 and the second flow path 2, the cooling water that has traveled straight through the respective flow paths changes direction substantially vertically at the junction 3. Then, they are agitated and ejected from the discharge holes 4. At this time, the amount of water poured into the discharge hole 4 from the first channel having a larger channel cross-sectional area is larger than the amount of water poured into the discharge hole 4 from the second channel having a smaller channel cross-sectional area. Therefore, the cooling water ejected from the discharge holes 4 is asymmetrically distributed with respect to the ejection center plane 9, that is, a large amount of cooling water is ejected from the second flow path side.

FIG. 2 is a schematic diagram showing a state of cooling water ejected from the cooling nozzle shown in FIG.
2, since the cooling nozzle 10 injects the cooling water asymmetrically as described above, the surface 20h perpendicular to the injection center plane 9 has a mountain shape “O to A1 to A2. -It has a flow rate distribution schematically shown by A7 ". That is, a clear peak A5 appears on the second channel side (right side in the figure). Further, if the vertical surface 20h is moved away from the cooling nozzle 10, the flow rate per unit area simply decreases while maintaining the asymmetric flow rate distribution.
On the other hand, on the surface 20 s inclined with respect to the injection center plane 9, the flow rate per unit area decreases as the distance from the cooling nozzle 10 increases as described above, but on the side where the flow rate is higher than the injection center plane 9 (FIG. If the center (right side) is further distant, the asymmetric flow rate distribution is relaxed, and the non-uniformity of the flow rate per unit area is eliminated.

That is, as schematically shown by a substantially trapezoidal shape “O to B1 to B2... B7” whose top is substantially flat, the peak A5 disappears and the flow rate per unit area is substantially uniform over a wide range.
Therefore, even if it is necessary to incline the injection center plane 9 with respect to the surface of the steel material, the coverage is within the range corresponding to the positions “B2 to B7” or the range corresponding to the positions “B3 to B7”. If the cooling surface is positioned, the cooling is performed substantially uniformly except for the position “B7” at the extreme end of the surface to be cooled.
On the other hand, although the injection center plane 9 is perpendicular to the surface of the steel material, for example, there is an obstacle, and the center in the width direction of the steel material must be offset (offset) with respect to the injection center plane 9. Even in this case, if the surface to be cooled is positioned within the range corresponding to the positions “A2 to A6” or the range corresponding to the positions “A3 to A6”, the entire area of the cooled surface is substantially uniform. It will be cooled down.

FIG. 3 is a schematic diagram showing the state of cooling water ejected from a conventional cooling nozzle, for explaining the difference from the cooling nozzle in the present invention shown in FIG.
In FIG. 3, the conventional cooling nozzle 90 injects cooling water symmetrically with respect to the injection center plane 9, and therefore, in a plane 20 h perpendicular to the injection center plane 9, a chevron “O ~ C1-C2 ... C7 ". That is, a clear peak C3 appears on the injection center plane 9. Further, if the vertical surface 20h is moved away from the cooling nozzle 90, the flow rate per unit area is simply reduced while maintaining the symmetrical flow rate distribution.

On the other hand, on the surface 20s inclined with respect to the injection center plane 9, the flow rate per unit area decreases as the position moves away from the cooling nozzle 90 (right side in the figure) as described above, so the flow rate distribution becomes asymmetric. Therefore, the non-uniformity of the flow rate per unit area becomes remarkable.
That is, a larger amount of cooling water is supplied to the side closer to the cooling nozzle 90 (left side in the figure) to form the peak D2, and supplied to the side farther from the cooling nozzle 90 (right side in the figure). It exhibits a flow rate distribution schematically shown by asymmetrical mountain shapes “O to D1 to D2... D7” in which a gentle skirt is formed with a small amount of cooling water. That is, the flow rate per unit area is not uniform over a wide range.

Therefore, when the injection center plane 9 must be inclined with respect to the surface of the steel material, for example, there is an obstacle, for example, a range corresponding to the positions “D2 to D7”, or, for example, there is an obstacle. If the surface to be cooled is positioned within the range corresponding to the position “D3 to D7” in the width direction of the steel material, the surface to be cooled is not cooled uniformly. This is the same as the fact that the surface to be cooled, which is cooled substantially uniformly, becomes extremely narrow. Therefore, when cooling a steel material having a surface to be cooled with a predetermined spread, a plurality of cooling nozzles can be installed. It became necessary to move the cooling nozzle.
Similarly, when the injection center plane 9 is perpendicular to the surface of the steel material but the center in the width direction of the steel material has to be displaced (offset) with respect to the injection center plane 9, for example, the position “C2 When the surface to be cooled is located within the range corresponding to “C6” or within the range corresponding to the positions “C3 to C6”, the cooling of the surface to be cooled is not uniform.

  Therefore, according to the cooling nozzle 10 of the present invention, when the surface of the steel material is inclined with respect to the injection center plane 9 (same as not perpendicular) or offset, it is uniform over a wide range of steel materials. It can be seen that proper cooling is performed.

(H-shaped steel cooling method)
4 and 5 show equipment used for the cooling method of the H-section steel according to the embodiment of the present invention. FIG. 4 is a schematic diagram outlining the hot rolling line, and FIG. 5 shows the cooling equipment. It is a schematic diagram outlined.

(Hot rolling line)
In FIG. 4, a hot rolling line 100 includes a rough rolling machine 110 for roughing a hot rolled material (bloom) heated or adjusted to a predetermined temperature, and a material to be rolled hot rolled to the rough shape. A finishing mill 130 for converting the H-section steel into a predetermined cross-sectional shape, a cooling facility 200 for cooling the H-section steel hot-rolled to the finished shape to a predetermined cooling stop temperature at a predetermined cooling rate, A sawing machine (not shown) that cuts the H-shaped steel whose predetermined material strength is guaranteed by the cooling into a predetermined length. At this time, the surface temperature of the material to be rolled is measured by the thermometers 120 and 140, and rolling in which the processing temperature and the processing amount are controlled is performed. A plurality of transport rollers 150 are disposed between these devices, and a transport table is formed by an apron (not shown) disposed between one transport roller 150 and the other transport roller 150.

(H-shaped steel cooling equipment)
In FIG. 5, the H-section steel cooling facility 200 (hereinafter referred to as “cooling facility 200”) includes a flange outer surface cooling section 230 that cools the outer surface 23 f of the flange 20 f of the H-section steel 20, and a flange 20 f of the H-section steel 20. A flange lower inner surface cooling part 210 that cools the lower inner surface 21f and a flange upper inner surface cooling part 220 that cools the upper inner surface 22f of the flange 20f of the H-section steel 20 are provided. In addition, in FIG. 5, since the cooling equipment 200 and the H-section steel 20 are bilaterally symmetrical, the code | symbol is attached | subjected only to the one side about each site | part.

(Flange lower inner surface cooling section)
The lower flange inner surface cooling section 210 is installed between the conveying rollers 150 at a position lower than the surface connecting the apexes of the conveying rollers 150, and is directed toward the lower inner surface 21f of the flange 20f of the H-shaped steel 20 being conveyed. And a cooling nozzle 10 for injecting cooling water obliquely upward.
The cooling water reaches the cooling nozzle 10 via a cooling water pipe 211 from a cooling water pumping means (including a pumping pump, a switching valve, a valve control device, etc.) (not shown). At this time, the injection center plane and the lower inner surface 21f of the flange 20f form, for example, an angle of 50 °. Here, the angle formed by the injection center plane and the lower inner surface 21f of the flange 20f is the center line of the tip section of the cooling nozzle (the center line of the section of the tip discharge hole 4 in FIG. 1) and the surface of the flange inner surface of the steel material. Say the angle between.
Further, since the cooling water pipe 211 is installed on the connecting base 212 connected to the flange outer surface cooling unit 230, the cooling nozzle 10 moves integrally with the flange outer surface cooling unit 230.
Since the cooling nozzle 10 injects the cooling water asymmetrically as described above, the lower inner surface 21f of the flange 20f is the same as the intersection between the lower end portion and the fillet portion (the lower inner surface 21f of the flange 20f and the lower surface of the web 20w). ) Over a wide range is cooled substantially uniformly.

(Flange upper inner surface cooling part)
The flange upper inner surface cooling unit 220 is installed at a predetermined distance from the conveying roller 150 in order to avoid a collision with the conveyed H-section steel 20, and is formed on the upper inner surface 22f of the flange 20f of the conveyed H-section steel 20. A cooling nozzle 10 for injecting cooling water obliquely downward is provided.
The cooling water reaches the cooling nozzle 10 via a cooling water pipe 221 from a cooling water pumping means (which includes a pumping pump, a switching valve, a valve control device, etc.) not shown. At this time, the injection center plane and the upper inner surface 22f of the flange 20f form, for example, an angle of 50 °. Further, since the cooling water pipe 221 is installed on the connection mount base 222 connected to the flange outer surface cooling unit 230, the cooling nozzle 10 moves integrally with the flange outer surface cooling unit 230.
Since the cooling nozzle 10 injects cooling water asymmetrically as described above, the upper inner surface 22f of the flange 20f extends from the upper end portion to the fillet portion (the same as the intersection of the upper inner surface 22f of the flange 20f and the upper surface of the web 20w). A wide range is cooled substantially uniformly.

(Flange outer surface cooling section)
The flange outer surface cooling unit 230 includes a plurality of water storage chambers (not shown) partitioned by a plurality of partition walls, and the wall surface on the rolling line side of the water storage chamber functions as a guide for conveying the H-section steel 20, A number of cooling water outflow holes (not shown) drilled in the wall surface function as cooling nozzles (same as the so-called “perforated plate water cooling nozzle”). Since the pitch of the cooling water outflow holes can be arbitrarily selected, cooling at a high water density such as 1000 to 3000 liters / minute m ² ((liter / min / m ² ) can be easily realized.
Further, since the flow rate and pressure of the cooling water supplied to each water storage chamber are controlled by control means (not shown), a laminar flow with a predetermined flow rate is formed from the cooling water outflow hole, and desired cooling is performed. Will be.

The flange outer surface cooling unit 230 is installed on a movable carriage (not shown) that can move forward and backward in the width direction of the rolling line, and advances and retracts according to the web width of the H-section steel 20 (same as the beam). The flange outer surface cooling unit 230 can perform cooling of the outer surface 23f at a suitable position from the outer surface 23f of the flange 20f.
Further, since the cooling water pipe 211 and the cooling water pipe 221 are installed on the same movable carriage as the flange outer surface cooling unit 230, the cooling nozzles 10 of the flange lower inner surface cooling unit 210 and the flange upper inner surface cooling unit 220 are flanged. The cooling of the lower inner surface 21f and the upper inner surface 22f of 20f can be respectively performed.

(Example)
In the following, examples of the present invention will be described with respect to an H-shaped steel having a web height of 800 mm, a web thickness of 19 mm, a flange width of 400 mm, and a flange thickness of 40 mm after hot finish rolling.
That is, in the H-section steel manufacturing facility shown in FIG. 4, the H-section steel is subjected to rough rolling and finish rolling in the rolling mill 110 and the finishing mill 130, and then cooling water is supplied to the inner and outer surfaces of the flange in the cooling facility 200. . At the rear (right side in the figure) of the cooling facility 200, the surface temperature distribution of the outer surface 23f of the flange 20f after recuperation is measured by the radiation thermometer 140 to perform quality control.
This product is required to have a tensile strength of 490 MPa or more. To that end, it is determined whether the surface temperature of the outer surface 23f of the flange 20f after reheating is within the range of 580 to 660 ° C., and quality control is performed. Is going.

In addition, Comparative Example 1 for comparison uses a conventional cooling nozzle having an elliptical discharge hole at the front end of a single flow path, and Comparative Example 2 for comparison includes the first The cooling nozzle includes a flow path and a second flow path, and each flow path has an equal (1: 1) cross-sectional area.
In addition, Examples 1 and 2 of the present invention and Reference Example are cooling nozzles each having a first channel and a second channel, and Example 1 is a channel of the first channel. In the second embodiment, the cross-sectional area of the second flow path is twice (2: 1) the cross-sectional area of the second flow path. In the reference example , which is four times the area (4: 1), the cross-sectional area of the first channel is six times the cross-sectional area of the second channel (6: 1). is there.
And in any of the comparative examples 1 and 2, Examples 1 and 2, and the reference example , the amount of cooling water per cooling nozzle is 80 liters / minute (liter / min).

Table 1 shows the measurement results after recuperation of the outer surface temperature of the flange 20f in Comparative Examples 1 and 2, Examples 1 and 2, and Reference Example (flange end, quarter part, fillet part), tensile test results, and alloys This is a summary of cost comparison of component addition.
In any case, the outer surface 23f of the flange 20f was cooled substantially uniformly. Further, the temperature distribution in the flange width direction after recuperation measured by the radiation thermometer 140 and the tensile test result obtained by cutting out a part of the product substantially correspond to the water amount distribution of the cooling water supplied to the flange inner surface. .

(Comparative Example 1)
In Comparative Example 1, since a conventional cooling nozzle having an elliptical discharge hole was used, the injection angle was narrow, and the cooling water was concentrated on a quarter portion of the flange width (hereinafter referred to as “quarter portion”). The quarter section was sufficiently cooled to 610 ° C. Cooling water was hardly supplied to the position 30 mm from the flange end (hereinafter referred to as “flange end”) and the fillet, and the water cooled only to 685 ° C. and 700 ° C., respectively.
In the tensile test, the required strength could be secured in the quarter part, but not in the other parts. As a result, it is necessary to add a new alloy component, which increases the manufacturing cost.

(Comparative Example 2)
In Comparative Example 2, the flow passage cross-sectional area ratio was set to 1: 1 using a cooling nozzle having two flow passages. Since the flow from each flow path merges and stirs near the discharge hole, the injection angle is larger than that of the conventional cooling nozzle used in Comparative Example 1, and the cooling water can be supplied also to the vicinity of the fillet. However, since the flow rate distribution of the cooling water is symmetric with respect to the injection center plane as shown in FIG. 3, the cooling water is concentrated on the near side of the quarter portion close to the cooling nozzle, that is, on the flange end side. The amount of cooling water reaching the farthest fillet was small. As a result, the temperatures of the flange end portion, the quarter portion, and the fillet portion were 625 ° C., 650 ° C., and 670 ° C., respectively.
In the tensile test, the strength required at the flange end and the quarter portion could be secured, but there were some cases where the strength could not be secured at the fillet portion. The production cost was slightly high because a few alloy components were newly added due to the lack of strength.

Example 1
In Example 1, the flow passage cross-sectional area ratio was set to 2: 1 using a cooling nozzle having two flow passages. Since the main flow with the larger channel cross-sectional area is injected farther from the injection center plane of the cooling nozzle injection, the flow rate distribution of the cooling water reaching the flange inner surface is compared as shown by the inclined surface 20s in FIG. The uniformity of cooling has improved dramatically. As shown in Table 1, the temperatures at the flange end, quarter portion, and fillet portion are all within the allowable range for quality control.
In the tensile test, the required strength was ensured in all parts. Since it was not necessary to newly add an alloy component, the manufacturing cost could be kept low.

(Example 2)
Example 2 uses a cooling nozzle having two channels of flow paths and has a channel cross-sectional area ratio of 4: 1, and Example 1 (channel cross-sectional area ratio of 2: 1) and Similar effects were obtained.

(Reference example)
In the reference example , a cooling nozzle having two channels is used and the channel cross-sectional area ratio is 6: 1. The main flow with the larger flow path cross-sectional area was injected farther from the center line of the cooling nozzle injection, but the flow rate of the main flow was too high, and the vicinity of the fillet portion cooled intensively. Conversely, the amount of cooling water supplied to the flange end was too small. As a result, the temperatures of the flange end portion, the quarter portion, and the fillet portion were 670 ° C., 640 ° C., and 625 ° C., respectively.
In the tensile test, the required strength at the quarter part and fillet part could be secured, but there were some cases where it could not be secured at the flange end. The production cost was slightly high because a few alloy components were newly added due to the lack of strength.

In addition, this invention has a remarkable effect when the angle which the injection direction of a cooling water and the cooling surface make is 30-75 degrees.
That is, when the angle is close to the vertical of 75 to 90 °, the flow rate distribution is not greatly deviated (corresponding to variation) even with cooling in the conventional cooling nozzle (see Comparative Example 1 or Comparative Example 2). The cooling nozzle of the present invention (characterized by the asymmetric distribution of the jetted cooling water) is not used. However, it is clear that the cooling nozzle of the present invention is effective when more uniform cooling is required at an oblique angle of 30 to 75 °.
On the other hand, when the angle is less than 30 °, even if the cooling nozzle of the present invention is used, the inclination is too large, and it becomes difficult to control and supply cooling water to a predetermined cooling surface. However, when such a case is unavoidable, it is clear that the cooling nozzle of the present invention is superior to the conventional cooling nozzle.

In Examples 1 and 2, the cross-sectional area ratio of the flow path is shown as 2: 1 to 4: 1, but this is the most suitable condition for using the technology of the present invention, and other area ratios. However, some effect is exhibited. For example, in the comparative example 2 and the reference example , the temperature of the flange is at most 670 ° C., and the cost of the alloy component can be somewhat reduced as compared with the comparative example 1 using the conventional technique.

The present invention is suitable for cooling the H-shaped steel after hot rolling, that is, when cooling the lower inner surface of the flange by installing a cooling nozzle below the pass line. That is, the H-shaped steel to be conveyed does not collide with the cooling nozzle, and the cooling nozzle of the present invention injects the cooling water asymmetrically in response to the cooling water being inclined with respect to the cooling surface. Because it can.
On the other hand, when cooling the lower inner surface of the flange, installing the cooling nozzle above the pass line is not preferable because the cooling nozzle is damaged when the H-shaped steel is twisted and conveyed and collides with the cooling nozzle. In addition, since the angle formed by the spray spray and the cooling surface is nearly vertical, the effect of the present invention cannot be fully exhibited.

In addition, when the H-shaped steel after hot rolling is transported, the cooling nozzle is disposed above the height of the H-shaped steel to cool the inner surface of the upper part of the flange. Therefore, it is preferable.
On the other hand, when the cooling nozzle is not installed above the height of the H-shaped steel, that is, when the cooling nozzle is installed between the upper and lower flanges of the H-shaped steel, the H-shaped steel collides with the cooling nozzle and the cooling nozzle is damaged. This is not preferable because there is a possibility. In addition, since the angle formed by the spray spray and the cooling surface is nearly vertical, the effect of the technique of the present invention cannot be sufficiently exhibited.

(Other embodiments)
As mentioned above, although the case where the flange inner surface of H-section steel is cooled is explained as an example as an embodiment of the present invention, the present invention is not limited to this. It may be applied to the case of spraying on a steel pipe, or may be used when spray cooling is performed by arranging a cooling nozzle around a steel pipe.
Further, the present invention is not limited to a steel material literally, and can be applied to cooling of non-ferrous metals and non-metallic materials.

Further, as the cooling nozzle for injecting the cooling water asymmetrically, the one having a pair of flow paths having different flow path cross-sectional areas has been described, but the present invention is not limited to this. For those having a pair of flow paths having the same or different cross-sectional areas, the pressure of cooling water supplied to each flow path may be different, or the position of the discharge hole may be provided close to one flow path Good.
In addition, even if the quantity of the cooling water injected is apparently symmetric, it is within the scope of the present invention that the cooling capacity of the injected cooling water is asymmetric.
Further, the procedure for forming the pair of flow paths is not limited, and may be formed separately, or a common flow path may be formed and divided into a pair of flow paths by a partition plate. Good.

As described above, the cooling method for the H-shaped steel of the present invention can be widely used as a cooling method for various materials in the case where the normal line of the surface to be cooled and the injection center plane of the cooling nozzle are not parallel.

The cooling nozzle used for the cooling method of the H-section steel which concerns on embodiment of this invention is shown typically, Comprising: (a) is a rear view, (b) is sectional drawing of a side view, (c) is a front view Figure. The schematic diagram which shows the mode of the cooling water injected from the cooling nozzle shown in FIG. The schematic diagram which shows the mode of the cooling water injected from the conventional cooling nozzle. The schematic diagram which outlines the hot rolling line which shows the installation used for the cooling method of the H-section steel which concerns on embodiment of this invention. The schematic diagram outlining the cooling equipment which shows the equipment used for the cooling method of the H-section steel which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st flow path 2 2nd flow path 3 Merge part 4 Discharge hole 5 Front end surface 6 Main body 7 Rear end surface 8 Screw 9 Injection center surface 10 Cooling nozzle 20 Shaped steel 20f Flange 20h surface 20s surface 20w Web 21f Lower inner surface 21w Lower surface 22f Upper inner surface 23f Outer surface 100 Hot rolling line 110 Rough rolling mill 120 Thermometer 130 Finishing mill 140 Radiation thermometer 150 Conveying roller 200 Cooling equipment 210 Flange lower inner surface cooling section 211 Cooling water piping 220 Flange upper inner surface cooling section 221 Cooling water piping 230 Flange outer surface cooling section

Claims (4)

In the cooling zone of the hot rolling line forming the H-section steel, which is a steel material, both at a position lower than the apex of the transport roller for transporting the H-section steel and at a position higher than the flange height of the transported H-section steel A discharge hole formed in the tip surface, a first flow path for pouring cooling water into the discharge hole, and a second flow for pouring cooling water into the discharge hole at a flow rate smaller than the flow rate of the first flow path A step of disposing a cooling nozzle having a flow path toward the flange inner surface so that the first flow path side is closer to the flange inner surface of the H-shaped steel than the second flow path side. When,
Injecting cooling water from the cooling nozzle toward the flange inner surface of the H-shaped steel ;
A flange outer surface cooling section comprising a plurality of water storage chambers partitioned by a plurality of partition walls and a number of cooling water outflow holes drilled in one wall surface of the water storage chamber, the wall surface transporting the H-shaped steel Arranging to function as a guide for
Forming a laminar flow with a predetermined flow rate from the cooling water outflow hole;
Have
The method of cooling an H-section steel, wherein the surface temperature of the outer surface of the flange of the H-section steel is within the range of 580 to 660 ° C when reheated after passing through the cooling zone. The flow path cross-sectional area of the first flow path of the cooling nozzle is, the second cooling nozzle of 2-4 times the channel cross-sectional area of the flow path of claim 1, wherein the a size H-shaped steel cooling method. The method of cooling an H-section steel according to claim 1 or 2, wherein a central axis of a tip section of the cooling nozzle is inclined by 30 to 75 ° with respect to a surface of an inner surface of the flange of the H-section steel . The flange outer surface cooling section and the cooling nozzle are installed in a movable carriage that can advance and retreat in the width direction of the hot rolling line, and the movable carriage is advanced and retracted according to the web width of the H-section steel. The cooling method of the H-section steel according to any one of claims 1 to 3, wherein cooling of the flange outer surface and the flange inner surface of the H-section steel is performed.

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