JPH0523844B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for cooling a rolling roll in a rolling mill, and in particular, a cooling water jacket is provided along the outer periphery of the rolling roll so that the cooling water comes into contact with the outer periphery of the rolling roll, and a cooling water jacket is provided within the cooling water jacket. The present invention relates to an improvement in a method of cooling mill rolls during rolling by supplying roll cooling water.

[Conventional technology]

In hot rolling, a large amount of heat flux is generated from the material to be rolled to the rolling rolls during rolling, resulting in rough skin due to thermal fatigue of the rolls and thermal expansion in the threaded portion of the rolls. In order to prevent surface flaws and poor flatness caused by these, it is necessary to cool the rolling rolls. Conventionally, rolling rolls were cooled by spraying cooling water onto the roll surface during rolling, and the sprayed cooling water collided with the roll surface, where heat was exchanged. . The problem with this type of spray cooling method is that the area where the cooling water contacts the roll is limited, and even if the amount of cooling water is increased, the cooling area does not change, making it impossible to achieve a significant increase in the cooling effect. The point was hot. In addition, the cooling water that is sprayed and collides with the rolling rolls scatters and falls onto the material to be rolled, reducing the rolling temperature, which wastes a lot of energy and makes it difficult to control the material quality of the material to be rolled. There was a problem with this. Furthermore, the cooling water after being sprayed onto the rolling rolls becomes hot water and falls into the srule below the rolling mill, where it is collected together with descaling and other cooling water and oil after hydraulic rolling, and circulated through water treatment equipment. has been done. Therefore, it is impossible to control the temperature or improve the water quality of the roll cooling water alone. Therefore, from the point of view of temperature control and water quality of the roll cooling water,
There were limits to the quality improvement of rolled materials. On the other hand, as shown in Japanese Patent Publication No. 55-12322, for example, cooling efficiency can be improved by installing a water jacket along the surface of the rolling roll and supplying cooling water to this water jacket. A so-called water jacket type roll cooling method has been proposed to improve the roll cooling. Furthermore, as proposed in Utility Model Application No. 58-52752, a closed cycle is formed in which the cooling water supplied to the water jacket is directly recovered, thereby reducing the amount of cooling water used. There is a method that prevents cooling water from leaking onto the rolled material after cooling. By the way, a rolling roll does not contact and roll the material to be rolled over its entire width range, but the range in the axial direction in which it contacts the material to be rolled depends on the width of the material to be rolled. , that is, the width of the threading section changes,
Further, both ends of the rolling roll in the axial direction do not always come into contact with the material to be rolled. Therefore, during rolling, a large amount of heat flux is generated from the material to be rolled mainly at the central position in the axial direction of the roll, and thermal expansion occurs in the threaded portion of the roll. In particular, the heat dissipation efficiency is higher at both ends of the roll compared to the center in the axial direction, so the temperature distribution in the longitudinal direction of the roll is highest at the center and lowest at both ends, and is not necessarily uniform in the axial direction of the roll. do not have. On the other hand, in the case of the conventional water jacket type roll cooling method, the mill roll is cooled uniformly in its axial direction, and therefore the axial center of the mill roll may be insufficiently cooled or There is a problem that both end side portions tend to be supercooled, making it impossible to control the thermal expansion distribution (thermal crown) in the axial direction of the roll, making it difficult to perform highly accurate rolling. On the other hand, as disclosed in, for example, Japanese Utility Model Application Publication No. 57-141807, a nozzle head consisting of storage chambers separated and arranged in series in the axial direction of the roll is disposed close to the roll, and each of the storage chambers is There is a roll temperature distribution control device configured to supply a temperature control fluid to each chamber.

[Problems to be solved by the invention]

This device can arbitrarily control the distribution of thermal expansion in the axial direction of the rolling rolls, but because the partitions that partition each storage chamber do not come into sufficient contact with the temperature control fluid, the roll cooling in the partitions is insufficient. Therefore, there was a problem that the distribution of thermal expansion in the axial direction of the rolling roll could not be sufficiently controlled.

[Means to solve the problem]

This invention provides a cooling water jacket along the outer periphery of the roll so that the cooling water comes into contact with the outer periphery of the roll, and divides the cooling water jacket into a plurality of cooling zones in the longitudinal direction of the roll. In a rolling roll cooling method in which a cooling water system is provided independently in each of these cooling zones and the roll is cooled in each cooling zone, the boundaries of the cooling zones are set along the roll rotation direction along the roll longitudinal direction. The above object is achieved by causing the cooling water in each cooling zone to flow in and out in the longitudinal direction of the roll at the boundary thereof. Further, the present invention achieves the above object by providing independent heat exchangers in the cooling water system of each of the cooling zones to perform circulating cooling in which the temperature of the cooling water can be controlled.

[Operation] This invention controls roll cooling for each of a plurality of cooling zones in the roll axis direction in a cooling water jacket formed along the outer periphery of the rolling roll, and also controls the boundary between each cooling zone along the roll circumferential direction. , the cooling water is caused to flow in and out in the longitudinal direction of the roll along the boundary, thereby forming an arbitrary distribution of thermal expansion in the axial direction of the rolling roll and achieving highly accurate rolling. It is possible.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, as shown in FIGS. 1 and 2, a cooling water jacket 12 is provided along the outer periphery of the rolling roll 10 so that the cooling water comes into contact with the outer periphery of the rolling roll 10. Cooling water jacket 12
In the method of cooling the roll roll 10 during rolling by supplying roll cooling water inside the roll, the cooling water jacket 12 is divided into a plurality of cooling zones by a plurality of partition walls 14A to 14D arranged in parallel in the longitudinal direction of the roll roll 10. Separately divided into 16A to 16E,
In addition, cooling water systems 18A to 18E are provided independently in each of these cooling zones 16A to 16E, and roll cooling is controlled for each cooling zone 16A to 16E. Cooling water system 1 for each of the cooling zones 16A to 16E
8A to 18E are independent heat exchangers 20A to 2, respectively.
Equipped with 0E, it is possible to control the cooling water temperature. In FIG. 1, reference numeral 22 indicates a material to be rolled, and 24 indicates a back-up roll. The cooling water systems 18A-18E connect to the cooling zones 16A-16E via water supply ports 26A-26E and drain ports 28A-28E for each cooling zone 16A-16E.
16E, and the water supply pump 3
It is considered as an independent close cycle with 0A to 30E. The heat exchangers 20A to 20E can independently control the heat exchange rate with a heat exchanger medium made of, for example, air, thereby making it possible to freely control the temperature of the cooling water. Since the structure of the heat exchanger is conventionally well known, the explanation thereof will be omitted. The partition walls 14A to 14D are formed in an arc shape along the circumferential direction of the roll 10 and are arranged in parallel in the axial direction of the roll. Further, the cross-sectional shape of the partition walls 14A to 14D in the roll circumferential direction is formed to meander in the rotational direction of the mill roll 10. That is, the boundaries of each cooling zone 16A to 16E are along the roll circumference,
The roll is moved in and out in the longitudinal direction. In the above embodiment, each cooling water system 18A to 18
After the cooling water E is cooled to a target temperature in each of the heat exchangers 20A to 20E, it is sent to the cooling zone 16 of the cooling water jacket 12 from the water supply ports 26A to 26E by the water supply pumps 30A to 30E.
A to 16E are supplied. These cooling zones 16A to 16E are formed along the outer circumferential surface of the roll 10 and along the rotational direction of the roll 10, so that the cooling zones 16A to 16E are
0 surface, i.e. cooling zone 1 while cooling.
6A to 16E, and returns to the heat exchangers 20A to 20E through drain ports 28A to 28E, where it is cooled again to the target temperature, and then reaches the cooling water jacket 12 for circulating cooling. Since the heat exchangers 20A to 20E can arbitrarily control the temperature of the cooling water passing through them, the cooling rate of the rolling roll 10 in each cooling zone 16A to 16E in the cooling water jacket 12 can be arbitrarily selected. be able to. Therefore, for example, by making the temperature of the cooling water lowest in the cooling zone 16C at the central position in the roll axis direction and relatively high cooling water temperature in the cooling zones 16A and 16E at both ends in the roll axis direction, rolling can be carried out. The surface temperature distribution of the roll 10 can be made uniform. Also, depending on the rolling state, the temperature of the cooling water in a portion other than the cooling zone 16C at the center in the axial direction of the roll is set to the lowest, so that the rolling roll 10 is cooled to an arbitrary temperature distribution in the axial direction. be able to. For example, as shown in FIG. 3, the relationship between the distance from the axial center (roll center) of the roll 10 and the amount of thermal crown (amount of thermal expansion) on the surface of the roll, that is, the distribution of the amount of thermal crown is as follows: When the temperature of the cooling water in the cooling water jacket 12 is made the same in the roll axis direction, the amount of Saalmac crown at both ends in the roll axis direction is small;
It can be seen that the distribution is uniform in the middle part. On the other hand, if the cooling water temperature is varied in the roll axis direction within the cooling water jacket 12 according to the method of the present invention, as shown in FIG. 4, it can be seen that the thermal crown amount distribution can be controlled arbitrarily. Further, the partition walls 14A to 14D have a meandering shape in the rotational direction along the outer peripheral surface of the rolling roll 10,
Cooling water flows in and out along the partition walls 14A to 14D in the longitudinal direction of the rolls, and the points of contact between the rolling roll 10 and the partition walls 14A to 14D are not always the same in the roll axis direction. , the rolling roll 10 in this portion is reliably cooled and uniformly cooled. If the meandering width is increased, the temperature difference between the part corresponding to the partition wall and the part not corresponding to the partition wall can be reduced, and control with higher precision can be achieved. In the above embodiment, the cooling water jacket 12 is divided into five cooling zones 16A to 16E by partition walls 14A to 14D;
Alternatively, the cooling zone may be divided into six or more cooling zones. Further, in the above embodiment, the cooling water is made to flow in the cooling water jacket 12 along the rotational direction of the mill roll 10; You may also do so. When the rotation direction of the surface of the mill roll 10 is opposite to the cooling water flow and the cooling water is disturbed by the outer peripheral surface of the mill roll 10, cooling efficiency is improved. Further, in the above embodiment, the partition walls 14A to 14D have a meandering cross-sectional shape along the outer peripheral surface of the rolling roll 10 and in the rotation direction thereof, but the present invention is not limited to this. No, bulkhead 14A
-14D, it is sufficient if the cooling water flows in and out in the longitudinal direction of the roll.

【Effect of the invention】

Since the present invention is configured as described above, the thermal expansion distribution of the roll during rolling can be arbitrarily controlled in the axial direction of the roll, and therefore, rolling accuracy can be improved. It has this excellent effect.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a cooling water jacket and a rolling roll for carrying out the method for cooling a rolling roll according to the present invention, and FIG. 2 is a partial block diagram showing the cooling water jacket and cooling water system. A perspective view, Figure 3 is a diagram showing the thermal crown amount distribution when the cooling water temperature distribution in the cooling water jacket is made uniform in the roll axis direction, and Figure 4 is a diagram showing the distribution of the amount of thermal crown when the cooling water temperature is changed in the roll axis direction. FIG. 3 is a diagram similar to the first figure showing the distribution of Sahlma crown amount in the case of FIG. 10... Rolling roll, 12... Cooling water jacket, 14A to 14D... Partition wall, 16A to 16E...
...Cooling zone, 18A to 18E...Cooling water system, 2
0A to 20E... Heat exchanger, 22... Rolled material.

Claims (1)

[Claims] 1. A cooling water jacket is provided along the outer periphery of the rolling roll so that the cooling water comes into contact with the outer periphery of the rolling roll, and the cooling water jacket is distributed in a plurality of cooling zones in the longitudinal direction of the rolling roll. In a method for cooling a roll, in which the cooling water system is provided independently in each of these cooling zones, and the roll is cooled in each cooling zone, the boundary between the cooling zones is set along the direction of rotation of the roll. A method for cooling a mill roll, characterized in that the cooling water in each cooling zone is caused to flow in and out in the longitudinal direction of the roll at the boundary thereof. 2. The method for cooling a rolling roll according to claim 1, wherein the cooling water system of each cooling zone is provided with an independent heat exchanger to perform circulating cooling in which the temperature of the cooling water can be controlled. .