JPS60231511A - Cooling method of rolling roll - Google Patents

Abstract

PURPOSE:To improve the rolling accuracy by dividing a cooling water jacket to plural cooling zones in the longitudinal direction of a roll and adjusting and controlling the supply flow rate independently with each of the zones. CONSTITUTION:The cooling water jacket 12 is divided to independent cooling zones 16A-16D by plural partition walls 14A-14J. Cooling water systems 18A- 18K independent to correspond to the cooling zones form respectively independent closed cycles together with a common drain port 28, a heat exchanger 32 and a feed water pump 30. Shut off valves 20A-20K and variable throttling valves 21A-21K included in the systems 18A-18K can control optionally the flow rate of the cooling water passing through said valves. The cooling of the rolling roll at an optional temp. distribution in the axial direction of the rolling roll is thus made possible and the rolling accuracy is improved.

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 cold water comes into contact with the outer periphery of the rolling roll. The present invention relates to an improvement in a method for cooling a mill roll during rolling by supplying roll cooling water into the cooling water jacket.

[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 have been cooled by spraying cooling water onto the roll surface during rolling, causing the sprayed cooling water to collide with the roll surface, where heat exchange occurs. With this type of spray cooling method, the area in which the cooling water contacts the rolls 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. There was a problem. In addition, the cooling water that is sprayed and collides with the rolling rolls scatters and falls onto the material being rolled, which wastes a lot of energy and reduces the material quality of the material to be rolled in order to lower the rolling temperature. There was a problem in that it was difficult to control. Furthermore, the cooling water after being sprayed onto the rolling rolls becomes hot water and falls into the sluice 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. However, it is impossible to control the temperature or improve the water quality of the roll cooling water alone, so it is difficult to improve the quality of rolled materials from the viewpoint of humidity control and water quality of the roll cooling water. had its limits. On the other hand, as shown in Japanese Patent Publication No. 55-12322, for example, a water jacket is installed along the surface of the rolling roll and cooling water is supplied to this water jacket to improve the cooling efficiency. A so-called water jacket type roll cooling method has been proposed. In addition, as proposed by Jitsubiho 58-52752, for example, a closed cycle is formed in which the cooling water supplied to the woogie V-ket is directly recovered, thereby reducing the amount of cooling water used and reducing the amount of water after cooling. There is a method to prevent cooling water from wetting the rolled material. By the way, a rolling roll does not contact and roll a material to be rolled over its entire width range, but depending on the width of the material to be rolled, the range in the axial direction in which it contacts the material to be rolled, that is, the rolling The width of the part changes, and both axial ends of the rolling roll 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, since the heat generation efficiency is higher at both ends of the roll than at the center in the axial direction, the temperature distribution in the longitudinal direction of the roll is
It is highest at the center and lowest at both ends, and is not necessarily uniform in the roll axis direction. On the other hand, in the case of the conventional water jacket type roll cold phase method, the rolling roll is cooled uniformly in the axial direction, and therefore, the central part of the rolling roll in the axial direction is insufficiently cooled, and Both end portions tend to be overcooled, making it impossible to control the thermal expansion distribution (thermal crown) in the roll axis direction, which poses a problem in that highly accurate rolling becomes difficult. As shown in FIG. 3, the gate is moved by shifting the rolling roll 10 in the axial direction and changing the relative threading position of the rolled material 22 with respect to the axial center (roll center) of the rolling roll 10 by one coil. A method is used in which the shape of the coil is controlled by continuously rolling coils to be rolled having the same width while shifting the width by a fixed amount each time. In such a case, the rolling roll 10 is
The range in the roll axis direction in which direct heat conduction occurs changes sequentially in accordance with the shift position of the rolling mill 10. However, although the thermal crown at the position corresponding to the width of the rolled material plate appears to decrease in response to the shift 1- of the heat receiving part of the rolling roll 1o, the suppressing effect of the thermal crown itself of the rolling roll 1o is Without,
Therefore, there was a problem that rolling with sufficiently high precision could not be performed. An object of the present invention is to provide a method for cooling a mill roll by controlling (■) the cooling water of a mill roll. A method for cooling a rolling roll during rolling by providing a cooling water jacket along the outer periphery of the rolling roll so as to contact the rolling roll, and supplying roll cooling water into the cooling water jacket. is isolated and divided into a plurality of cooling zones in the longitudinal direction of the rolling roll, and each of these cooling zones is provided with a cooling water system that can independently adjust the amount of water supplied,
The above object is achieved by controlling roll cooling for each cooling zone. [Function] This invention controls roll cooling by adjusting the amount of cold river water supplied to each of a plurality of cooling zones in the roll axis direction within a cooling water jacket formed along the outer periphery of the rolling roll.
In this way, an arbitrary thermal expansion amount distribution in the axial direction of the rolling roll is formed, thereby enabling highly accurate rolling. (Example j) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In this example, as shown in FIGS. In the method of cooling the roll roll 10 during rolling by providing a cooling water jacket 12 along the outer periphery of the roll roll 10 and supplying roll cooling water into the cooling water jacket 12, the cooling water The jacket 12 is isolated and divided into a plurality of cooling zones 16A to 16K by a plurality of intervals 14A to 14J arranged in parallel in the longitudinal direction of the rolling roll 10, and
These cooling zones 168-16 are provided with cooling water systems 18A-18K which can independently adjust the amount of cooling water supplied, and roll cooling is controlled for each of the cooling zones 16A-16. Cooling water systems 188-1 for each of the cooling zones 16A-16E
8E is equipped with independent shutoff valves 20A to 20K and variable throttle valves 2'1A to 21K to enable control of the cooling water temperature. In FIG. 1, reference numeral 22 indicates a material to be rolled, and 24 indicates a backup roll. The cooling water systems 18A to 18 include respective cooling zones 16A to 18.
Water supply ports 26A to 26K and common drain port 28 every 16 days
The cooling zones 16A to 16K are each connected to the cooling zones 16A to 16K through the cooling zones 16A to 16K, and are independent clost cycles equipped with a common water supply pump 30 and a heat exchanger 32. The partition walls 14Δ to 14. J is formed in an arc shape along the circumferential direction of the roll 100 and in parallel in the axial direction of the roll. Further, the cross-sectional shape of the partition walls 14Δ to 14J in the roll circumferential direction is formed to meander in the rotational direction of the mill roll 10. In the above embodiment, the cooling water in each of the cooling water systems 18A to 18 is pressurized by the water supply pump 30, and the shutoff valves 20A to 20 are opened and closed, and the variable throttle valves 21A to 21 are controlled to open and close.
The flow rate is adjusted by adjusting the opening of the water supply ports 26A to 26.
cooling zone 16 of cooling water jacket 12 from K respectively.
These cooling zones 16A to 16 are formed along the outer peripheral surface of the roll 10 and along the rotation direction thereof, so that the surface of the roll 10 during rolling is and passes through the cooling zones 168 to 16K while being cooled, returns to the pump 30 from the drain port 28 via the heat exchanger 32,
The cooling water is circulated to the jacket I/12 as described above. The shutoff valves 20A to 20K and the variable throttle valve 21
In A to 21, since the amount of cooling water passing through these can be arbitrarily controlled, the cooling rate of the rolling roll 10 in each cooling zone 16Δ-16KL2 in the cooling water jacket 12 can be arbitrarily changed. can do. Therefore, for example, cooling zone 1 at the center position in the roll axis direction
By maximizing the amount of cooling water supplied at 6F and making the amount of cooling water supplied at cooling zones 16Δ and 16K at both ends of the roll axis relatively small, the surface temperature distribution of the rolling roll 10 can be made uniform. . Further, depending on the rolling state, the humidity of the cooling water in a portion other than the cooling zone 16F at the central portion in the axial direction of the roll may be set to the lowest to cool the rolling roll 10 to an arbitrary temperature distribution in the axial direction. can. For example, as shown in FIG. 3, by shifting the rolling roll 10 in the axial direction, the relative passing position of the rolled material 22 with respect to the axial center (roll center) of the rolling roll 10 is adjusted for each coil. When rolling coils of the same width are continuously rolled while shifting them by a certain amount, the range in the roll axial direction where heat is directly conducted from the rolled material 22 to the rolling o-ru 10 is the range of the rolling roll 10. It changes sequentially corresponding to the shift 1-fff position. As described above, in response to the shift of the heat-receiving portion of the roll 10, the thermal crown at the position corresponding to the width of the rolled material plate appears to decrease, but there is no effect of suppressing the thermal crown of the roll 10 itself, and therefore, By controlling the cooling of the rolling roll 10 in the axial direction, targeting only the portion corresponding to the sheet width, the thermal crown that grows in the portion corresponding to the sheet width disappears, and rolling with high IiI variation is achieved. Further, in the above embodiment, the cooling water is transferred to the cooling water jacket 12.
Although water is allowed to flow in the direction of rotation of the mill roll 10 in the direction of rotation of the mill roll 10, it may be made to flow in a direction opposite to the direction of rotation of the mill roll 100. When the rotation direction of the surface of the roll 10 is opposite to the cooling water flow and the cooling water is disturbed by the outer peripheral surface of the roll 10, cooling efficiency is improved. Further, in the above embodiment, the partition walls 14A to 14J 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. Instead, the partition walls 14Δ to 14J may be of any type as long as they divide the inside of the cooling water jacket 12 into a plurality of cooling zones in the roll axis direction. However, if the partition walls 14A to 14J have a meandering shape in the rotational direction along the outer peripheral surface of the roll 10, the roll 1
0 and partition walls 14A to 14. Since the contact points of J are not always the same in the roll axis direction, cooling of the mill roll 10 in this portion is made uniform. [Effects of the Invention] Since the present invention is configured as described above, the distribution of thermal expansion of the roll during rolling can be arbitrarily controlled in the axial direction of the roll, and therefore, rolling accuracy is improved. It has the excellent effect of being able to achieve the following.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a cooling water jacket and a mill roll for carrying out the method for cooling a mill roll according to the present invention, and FIG.
length, Fl perspective view including some block diagrams, Figure 3 is pressurized +
FIG. 4 is a diagram showing changes in the position of the roll heat receiving portion when the rolling rolls are shifted for each lot in the roll axis direction with respect to No. 4; 10... Rolling roll, 12... Cooling water jacket, 14, A~14, J... Partition wall, 168~16) <... Cooling zone, 18A to 18K... Cooling water system , 20A~20K...shirt 1~off valve, 21△~21
K...variable throttle valve, 22...pressure low interest. Agent Matsu 111 Keisuke (1 idiot) Figure 1 4 Figure 2 Figure 3 n

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 cooling water is supplied into the cooling water jacket during rolling. In the method for cooling a roll, the cooling water jacket is divided into a plurality of cooling zones in the longitudinal direction of the rolling roll, and each of the cooling zones is provided with a cooling water system that can independently adjust the amount of water supplied. A method for cooling mill rolls, characterized by controlling roll cooling for each cooling zone.