JP2006075856A - Method and apparatus for cooling h-section steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform the uniform cooling of an inner surface of flanges and the upper and back surfaces of the web of an H-section steel without requiring the extension of equipment length, devices having complicated constitution and highly accurate control. <P>SOLUTION: When cooling an outer surface 1aa of the flanges of the H-section steel 1, an inner surface 1ab of the flange and the upper and down surfaces 1ba, 1bb of the web at hot rolling, cooling water which stays on the upper surface 1ba of the web is dammed up on the inlet side and outlet side of the cooling and the wetted length of the staying water on the upper surface 1ba of the web and the inner surface in the upper part of the flange by this dammed-up staying cooling water is controlled. By installing nozzle groups C for performing cooling of the down surface 1bb of the web and the inner surface 1abb in the lower part of the flanges in a plurality of rows on the inlet side and outlet side of the cooling in the advancing direction of the H-section steel 1 and selecting the nozzles of the plurality of these rows, the cooling length of the down surface 1bb of the web and the inner surface 1abb in the lower part of the flanges is controlled. By independently performing them, the inward bending of the flanges after cooling is prevented. By this invention, the prevention of the inward bending of the flanges after cooling the H-section steel in which straightening by after-treatment is difficult is made possible. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling method and a cooling apparatus for H-section steel used for civil engineering structures and buildings, and more particularly, a cooling method for H-section steel after finish rolling in manufacturing H-section steel having high strength characteristics. And a cooling device.

  In recent years, H-section steel employed as a pillar material for civil engineering structures and buildings tends to increase in strength and thickness. Quenching treatment by cooling is effective as means for producing this high strength and thick H-shaped steel at low cost, and various cooling methods and cooling devices have been proposed.

  In particular, in the case of extremely thick H-section steel, since the web is relatively thick, it is necessary to cool the flange and the web uniformly by actively cooling the inner and outer surfaces of the flange and the upper and lower surfaces of the web. However, in the conventional cooling device, as shown in FIG. 7, cooling water sprayed from the spray nozzles 2 a to 2 e disposed outside the flange 1 a of the H-section steel 1 in order to prevent the occurrence of a web wave shape defect. Thus, only the outer surface of the flange 1a is cooled to reduce the temperature difference ΔT between the web and the flange to suppress the web wave shape defect, and the inner surface of the flange and the upper and lower surfaces of the web are not cooled.

Therefore, as a technique related to uniform cooling of the flange and the web, a technique of cooling by jetting water from a nozzle close to the flange inner surface, the web surface, or the fillet near inner surface is disclosed.
JP-A-6-297028

Also, a turbulent jet is sprayed on the upper concave portion surrounded by the upper flange inner surface and the web upper surface of the H-shaped steel to form a water pool, and the turbulent jet is formed on the lower concave portion surrounded by the lower flange inner surface and the web lower surface and the flange outer surface. A technique for cooling by jetting is disclosed.
JP-A-7-108316

Further, the inner surface of the flange and the upper surface of the web are arranged by a box type cooling device which is arranged along the longitudinal direction in the vicinity of 5 to 50 mm on the inner surface of the flange and the upper surface of the web and can control the supply of the cooling water to the inner surface of the flange and the upper surface of the web. Has been disclosed.
JP-A-7-188863

In addition, when cooling water accumulates on the upper surface of the web due to cooling while cooling the flange inner surface from the opposite side with cooling water sprayed from nozzles provided in a staggered manner across the pass line, the convection cooling Techniques for recovering water are disclosed.
JP 2003-19510 A

  However, in the technique described in Patent Document 1, when cooling, a cooling header is brought close to about 10 to 20 mm on the surface of a traveling high-temperature H-shaped steel, and further, against the meandering of the traveling H-shaped steel and deformation during cooling. However, there is a problem that it is necessary to control with high accuracy so as not to collide, and the manufacturing cost of the equipment and the control device becomes very high.

  Moreover, in the technique described in Patent Document 2, it is necessary to control the cooling header that can move in the web height direction in the upper concave portion of the traveling high-temperature H-section so as not to contact the H-section. However, it requires an advanced control device and a sturdy cooling header, and there is a problem that the equipment cost is greatly increased.

  Moreover, the technique described in Patent Document 3 can control flange cooling and web cooling independently, and can uniformly cool each part according to the difference in thickness and temperature unevenness in the longitudinal direction with the same temperature history. However, since it is necessary to control the position of the cooling header in the upper concave portion of the high-temperature H-shaped steel that travels, there is a problem that the manufacturing cost increases. In addition, it is not effective for preventing the inner and outer folds caused by the temperature difference between the inner and outer surfaces of the flange and the difference in cooling ability.

  In the technique described in Patent Document 4, only the flange portion is targeted for cooling on the inner surface side, and cooling of the web portion is not considered. And since the cooling of a flange part is also carried out in the crossing form from the nozzle arrange | positioned in zigzag form, a water quantity density cannot be enlarged and a cooling capability may be insufficient. Further, no consideration is given to a method for preventing deformation that occurs after water cooling.

  The problem to be solved by the present invention is that, in the manufacture of H-shaped steel, which tends to increase in strength and diversify from thick to thin, uniform cooling of the inner surface of the flange and upper and lower surfaces of the web and occurrence of internal bending (this occurs) In order to reduce the amount of time and cost required for shape correction in the next process, it is necessary to extend the equipment length, and it is necessary to have a complicated device and high-precision control. It is a point.

The present invention was made based on the results of experiments described later by the inventors,
The cooling method of the H-section steel of the first invention is as follows:
In order to enable uniform cooling of the inner surface of the flange and the upper and lower surfaces of the web, and suppression of internal folds, with a simple method,
When cooling the flange inner and outer surfaces of the H-shaped steel and the upper and lower surfaces of the web during hot rolling,
Blocking the cooling water staying on the upper surface of the web on at least one of the cooling inlet side and outlet side,
The main feature is to prevent the flange from being bent after cooling by controlling the wetting length of the web upper surface cooling zone and the wetting length of the flange upper inner surface cooling zone by the blocked staying cooling water.

  In the cooling method of the H-section steel of the present invention, the method of controlling the wetting length of the web upper surface cooling zone and the wetting length of the flange upper inner surface cooling zone by the staying cooling water is, for example, blocking the cooling water staying on the web upper surface. This can be done by changing the stop position.

Moreover, instead of the method for cooling the H-section steel of the present invention,
When cooling the flange inner and outer surfaces of the H-shaped steel and the upper and lower surfaces of the web during hot rolling,
In at least one of the cooling inlet side and outlet side, a plurality of nozzle groups are installed in the direction of travel of the H-section steel to cool the lower surface of the web and the inner surface of the flange lower part,
By selecting these plural rows of nozzles and controlling the cooling length of the lower surface of the web and the lower surface of the inner surface of the flange, it is possible to prevent bending in the flange after cooling. This is the second method for cooling the H-section steel of the present invention.

  Further, the control of the wet length of the staying cooling water for cooling the upper surface of the web and the upper inner surface of the flange by the cooling method of the first aspect of the present invention, and the cooling of the lower surface of the web and the lower inner surface of the flange by the cooling method of the second aspect of the present invention. The length may be controlled independently to prevent bending in the flange after cooling. This is the third method for cooling the H-section steel of the present invention.

The first inventive method comprises:
Cooling water staying on the upper surface of the web by cooling by the cooling device is placed on at least one of the inlet side and the outlet side of the cooling device on the inner and outer surfaces of the flange of the H-shaped steel and the upper and lower surfaces of the web, which are arranged in the hot rolling process. This can be implemented by the H-shaped steel cooling device of the first aspect of the present invention provided with a means for blocking. The cooling water blocking means may be any means that can block the cooling water, such as water spray, gas, and mist.

  Further, when a plurality of means for blocking the cooling water in the H-section steel cooling device of the first aspect of the present invention are installed in the traveling direction of the H-section steel, the cooling water staying on the upper surface of the web is blocked. By changing the position, the wet length of the staying water in the web can be controlled.

In addition, the second method of the present invention comprises:
A nozzle group capable of cooling the lower surface of the web and the lower surface of the inner surface of the flange is disposed on at least one of the inlet side and the outlet side of the cooling device for the H-shaped steel flange inner and outer surfaces and the upper and lower surfaces of the web arranged in the hot rolling process The cooling apparatus for H-section steel according to the second aspect of the present invention installed in a plurality of rows in the traveling direction of the H-section steel.

  The third method of the present invention can be carried out by the H-shaped steel cooling device of the third present invention provided with the first device of the present invention and the second device of the present invention.

  The present invention can prevent bending in the flange after cooling H-shaped steel, which is difficult to correct in post-processing, by simply installing a simple device on at least one of the inlet side and outlet side of existing cooling equipment. become.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.
FIG. 1 is a conceptual diagram illustrating an arrangement state of a cooling apparatus for H-section steel according to the present invention. FIG. 2 is a diagram illustrating a web on an inlet side and an outlet side for cooling the flange outer surface, flange inner surface, and upper and lower surfaces of the H-section steel. Fig. 3 is a conceptual diagram when blocking the cooling water staying on the upper surface. Fig. 3 shows flanges with different H-section steel sizes on the outer side of the flange of the H-shaped steel, the inner surface of the flange, and the inlet and outlet sides for cooling the upper and lower surfaces of the web. FIG. 4 is a conceptual diagram when cooling the lower inner surface and the lower surface of the web, FIG. 4 is a diagram illustrating a schematic configuration of a cooling device that cools the flange outer surface of the H-shaped steel, the flange inner surface, and the upper and lower surfaces of the web. It is a conceptual diagram in the case of cooling a flange upper part inner surface and a web upper surface with this cooling device.

  A is an apparatus that cools the outer surface 1aa of the flange 1a, the inner surface 1ab of the flange 1a, and the upper and lower surfaces 1ba, 1bb of the web 1b during the conveyance of the H-section steel 1, as shown in FIG. The outer surface 1aa of the flange 1a of the section steel 1 has five upper and lower rows of spray nozzles (hereinafter simply referred to as “nozzles”) arranged in the vicinity of the outer surface of the flange 1a along the conveying direction of the H-section steel 1. ) Cooled by cooling water sprayed from 2a to 2e. Further, as shown in FIG. 5, the upper inner surface 1aba of the flange 1a of the H-shaped steel 1 and the upper surface 1ba of the web 1b are arranged in two rows in the vertical direction above the outer surface of the flange 1a. The spray nozzles (hereinafter simply referred to as “nozzles”) 3a, 3b are cooled on the opposite side by cooling water sprayed from the upper inner surface 1aba of the opposite flange 1a toward the upper surface of the opposite web 1b. The

  On the other hand, the lower inner surface 1abb of the flange 1a of the H-section steel 1 has three rows of spray nozzles (hereinafter simply referred to as “nozzles”) arranged in the conveyance direction between the conveyance table rolls below the H-section steel 1. ) It is mainly cooled by the cooling water sprayed from the nozzles 4a and 4c on both sides of 4a to 4c, and the lower surface 1bb of the web 1b is sprayed from the central nozzle 4b of the three rows of nozzles 4a to 4c. Cooled mainly by cooling water.

  As shown in FIG. 1, the cooling device of the present invention has cooling water staying on the upper surface 1ba of the web 1b of the H-section steel 1 by cooling by the cooling device A on the inlet side and the outlet side of the cooling device A, for example. Two sets of blocking means B are provided at predetermined intervals in the conveying direction of the H-shaped steel, and the nozzle group C for cooling the lower surface 1bb of the web 1b and the lower inner surface 1abb of the flange 1a is formed in an H shape. A plurality of rows are installed in the traveling direction of the steel 1.

  By the way, the cooling water blocking means B allows the cooling water staying on the upper surface 1ba of the web 1b of the H-section steel 1 by cooling by the cooling device A to be in a predetermined position on the inlet side and the outlet side of the cooling device A. Any configuration can be used as long as it can be blocked.

  In this example, as shown in FIG. 2, nozzles 5a and 5b (for example, four nozzles at the upper stage and five nozzles at the lower stage in FIG. With cooling water sprayed at a discharge angle of 0.1 MPa or more (a spray wide angle of 15 degrees) at a spray angle of 45 degrees downward toward the upper surface of the web 1b of the H-section steel 1. Indicates things to stop.

  At this time, it may be blocked by a mist or gas jet. By this damming position, the cooling zone length of the inner surface 1ab of the flange 1a changes (cooling time changes), and the cooling stop temperature can be controlled.

Further, as shown in FIG. 3, as the nozzle group C for cooling the lower surface 1bb of the web 1b and the lower inner surface 1abb of the flange 1a, the lower surface 1bb and the flange 1a of the web 1b of the H-section steel 1 shown in FIG. The nozzles 4a to 4c having the same configuration as the nozzles 4a to 4c for cooling the lower inner surface 1abb are arranged in a plurality of rows (in this example, in the lower portion between the rolls) at a nozzle pitch of, for example, 200 mm in the conveyance direction between the conveyance table rolls (roll interval 1500 mm pitch) 6 sets of nozzle groups between rolls (6 intervals between rolls, total length 1.5 × 6 = 9 m, number of nozzle rows 7 × 6 = 42 rows), and the average water density is A system that can be cooled at a high water density of 500 liters / minute / m ² or more is installed.

  The cooling method of the H-section steel of the present invention uses, for example, the cooling device of the present invention configured as described above, and in addition to cooling by the cooling device A, the upper inner surface 1aba of the flange 1a by the cooling water blocking means B And the cooling ability (cooling time) of the cooling of the upper surface 1ba of the web 1b and the lower inner surface 1abb of the flange 1a and the lower surface 1bb of the web 1b by the nozzle group C, and the cooling stop temperatures of the flange inner surface and the upper and lower surfaces of the web are independent. Thus, the cooling zone length (cooling time) of the flange inner surface 1ab can be controlled, the cooling stop temperature of the inner surface 1ab and the outer surface 1aa of the flange 1a is adjusted, and the inner folding of the flange 1a is suppressed.

  For example, the control of the cooling capacity by the cooling water blocking means B uses the stagnant water on the upper surface 1ba of the web 1b, so that the cooling water from the cooling device A does not flow downstream or upstream of the cooling zone. By damming at the zone entrance and exit. At this time, the damming position is changed by selecting two cooling water blocking means B installed at a predetermined interval in the transport direction. Thereby, the cooling capability (cooling time) of the upper inner surface 1aba of the flange 1a can be controlled in two stages, for example, and the cooling stop temperature of the upper inner surface 1aba of the flange 1a can be changed.

  Further, in the nozzle group C, the cooling stop temperature is controlled by controlling the cooling length by ON / OFF control of the plurality of rows of nozzle groups installed in the transport direction. At this time, the cooling capacity can be controlled in two or more stages by making the number of nozzles (zone length) to be used selectable.

  In addition, according to the height size of the web 1b, the plurality of nozzles 4a to 4c, for example, the one having a large height of the web 1b uses all the nozzles 4a to 4c, and the one having a small height of the web 1b If the nozzles to be used are selected such that the nozzles 4a and 4c on both sides are not used, it is possible to prevent water from being scattered to the surroundings, which is effective in preventing temperature unevenness.

  That is, in the present invention, the cooling capability of the inner surface 1ab of the flange 1a is made larger than the cooling capability of the outer surface 1aa (the cooling zone length is made longer), and the cooling stop temperature is made lower than the outer surface 1aa of the flange 1a. After that, in the process where the entire H-section steel 1 is at room temperature, the shrinkage amount of the high-temperature flange outer surface 1aa increases, and the occurrence of deformation in the cooling floor seems to be outwardly folded (Fig. 6 (a )) Can be controlled.

  As a result, even if a deformation occurs, the final press correction becomes possible (in the case of the inward folding shown in FIG. 6B, it is necessary to correct it by manual heating of the burner, etc. The efficiency and yield of the next process (which becomes scrap) is greatly improved.

  Of course, when the cooling start temperature is the same and the rolling shape is good, it is best to start cooling at the same time and uniformly cool it so that there is no shape defect, and it is possible to control in this way. However, in the actual machine, the rolling shape is slightly different, the temperature of the flange inner surface is higher than that of the outer surface, and if the same cooling capacity is used for the same time, the outer surface temperature becomes slightly lower and eventually the inner flange is bent. Since there are many cases where heating correction is required in the work, it is practical to control the temperature as described above.

  In the present invention, it is further advantageous to further control the temperature of the cooling water to increase the cooling capacity to lower the stop temperature and to lower the stop temperature by 25 ° C. or lower, and to increase the stop temperature by decreasing the cooling capacity to increase the water temperature to 30 ° C. or higher. It is. In order to control the cooling capacity (cooling stop temperature), the conveyance speed is increased or decreased (decreasing the speed increases the cooling time and lowers the stop temperature).

  In other words, even if the length of the conventional cooling device A is simply extended and inner surface cooling is selectively used in the cooling zone at the front and rear ends, the accumulated water on the upper surface 1ba of the web 1b is tightly closed. If it is not stopped and discharged, the effect of shape control is not exhibited, and conversely the temperature unevenness increases and the shape defect increases. Moreover, extending the conventional cooling device A is disadvantageous because it is difficult to secure a space and the manufacturing cost becomes very high. On the other hand, the present invention can be manufactured at low cost without taking up space, and the shape control effect is sufficiently large and effective.

  In order to confirm the effect of the present invention, the above-described apparatus of the present invention (the zone length of the cooling device A is 30 m, the length of the cooling water blocking means B and the nozzle group C is 9 m for each of the inlet side and the outlet side) is used. Cooling in the case where the cooling method shown in Table 1 below was carried out to cool an H-shaped steel having a height of 500 mm, a width of 500 mm, and a web thickness of 20 to 35 mm (same as the flange) (the flange thickness is described in Table 1). The later shape was investigated.

  Examples 1 and 2 shown in the above Table 1 correspond to the present invention, and the cooling water in the cooling device A is blocked on the inlet side in the range of 9 m in Example 1 and 6 m in Example 2, In the first embodiment, the exit side was blocked in a range of 9 m, and in Example 2, the blocking was not performed.

  As a result, according to Examples 1 and 2, it was found that by changing the cooling zone length at the start and end of cooling, the H-section steel can be controlled to be bent outside the flange even when the flange thickness is large.

  In addition, using the same apparatus as that used in the experiment of Table 1, the cooling method shown in Table 2 below was performed to cool the H-section steel having a height of 500 mm, a width of 500 mm, a web thickness of 30 mm, and a flange thickness of 30 mm. In this case, the shape after cooling and the possibility of correction were investigated.

  As can be seen from Table 2 above, according to Example 3 and Example 4, it was confirmed that the desired shape could be controlled.

  The present invention is not limited to the above example, and it goes without saying that the embodiment may be appropriately changed within the scope of the technical idea described in each claim. For example, the cooling water blocking means B or the nozzle group C may be arranged on either the inlet side or the outlet side of the cooling device A, and the number of cooling water blocking means installed is limited to two. Absent. Further, the cooling device A may be one that cools only the outer surface 1aa of the flange 1a of the H-section steel 1 or the like.

  The present invention can be applied not only to cooling H-section steel but also to cooling other section steels.

It is a conceptual diagram explaining the arrangement | positioning state of the cooling device of the H-section steel of this invention. It is a conceptual diagram at the time of blocking the cooling water which retains on the web upper surface in the entrance side and exit side which cool the flange outer surface of H-section steel, a flange inner surface, and a web up-and-down surface. It is a conceptual diagram in the case of cooling the flange lower inner surface and the lower surface of the web with different H-section steel sizes on the inlet side and the outlet side for cooling the flange outer surface, flange inner surface, and web upper and lower surfaces of H-shaped steel. It is a figure explaining the schematic structure of the cooling device which cools the flange outer surface, flange inner surface, and web up-and-down surface of H section steel. FIG. 5 is a conceptual diagram in the case of cooling the flange upper inner surface and the web upper surface with the cooling device of FIG. 4, (a) is a perspective view, (b) is a front view, and (c) is a plan view. (A) is a figure explaining an outside fold, (b) is a figure explaining an inside fold. It is a conceptual diagram in the case of cooling only a flange outer surface.

Explanation of symbols

A Cooling device B Cooling water blocking means C Nozzle group 1 H section steel 1a Flange 1aa Outer surface 1ab Inner surface 1aba Upper inner surface 1abb Lower inner surface 2a-2e Nozzle 3a, 3b Nozzle 4a-4c Nozzle 5a, 5b Nozzle

Claims (8)

When cooling the flange inner and outer surfaces of the H-shaped steel and the upper and lower surfaces of the web during hot rolling,
Blocking the cooling water staying on the upper surface of the web on at least one of the cooling inlet side and outlet side,
By controlling the wetting length of the web upper surface cooling zone and the wetting length of the flange upper inner surface cooling zone by the blocked cooling water that is blocked, it is possible to prevent the H-section steel from being bent in the flange after cooling. Cooling method.   The control of the wetting length of the web upper surface cooling zone and the wetting length of the flange upper inner surface cooling zone is performed by changing the blocking position of the cooling water staying on the upper surface of the web. Cooling method for H-section steel. When cooling the flange inner and outer surfaces of the H-shaped steel and the upper and lower surfaces of the web during hot rolling,
In at least one of the cooling inlet side and outlet side, a plurality of nozzle groups are installed in the direction of travel of the H-section steel to cool the lower surface of the web and the inner surface of the flange lower part,
A cooling method for H-section steel, wherein the plurality of rows of nozzles are selected and the cooling length of the lower surface of the web and the lower surface of the inner surface of the flange is controlled to prevent bending in the flange after cooling.   The control of the wet length of the staying cooling water for cooling the upper surface of the web and the upper inner surface of the flange by the cooling method according to claim 1, and the cooling length of the lower surface of the web and the lower inner surface of the flange by the cooling method according to claim 3. The cooling method of H-section steel which implements control of this independently and prevents the bending in a flange after cooling. An apparatus for performing the method for cooling an H-section steel according to claim 1,
Cooling water staying on the upper surface of the web by cooling by the cooling device is placed on at least one of the inlet side and the outlet side of the cooling device on the inner and outer surfaces of the flange of the H-shaped steel and the upper and lower surfaces of the web, which are arranged in the hot rolling process. A cooling apparatus for H-section steel, characterized in that means for blocking is provided.   The cooling device for H-section steel according to claim 5, wherein a plurality of means for blocking the cooling water are installed in the direction of travel of the H-section steel. . An apparatus for performing the method for cooling an H-section steel according to claim 3,
A nozzle group capable of cooling the lower surface of the web and the lower surface of the inner surface of the flange is disposed on at least one of the inlet side and the outlet side of the cooling device for the H-shaped steel flange inner and outer surfaces and the upper and lower surfaces of the web arranged in the hot rolling process. A cooling apparatus for H-section steel, wherein a plurality of rows are installed in the traveling direction of the H-section steel. The apparatus of Claim 5 or 6 and the apparatus of Claim 7 were provided, The cooling device of the H-section steel which implements the cooling method of Claim 4 characterized by the above-mentioned.

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