JPH01215405A - Cooler for hot rolling mill - Google Patents

Abstract

PURPOSE:To maintain a smooth surface of rolls and to prevent flaws from generating by installing a cooling water receiver to be turnable, also installing a tension-transmitter hanging and bringing the receiver to be freely turnable on the opposite side of rolling rolls, and controlling the transmitter by a tension controller. CONSTITUTION:A tension value applied to a hanging member 12 is made to be zero in the case a sheet temp. is not higher than a certain temp., a counterclockwise moment centering around a supporting shaft 8 acts on a cooling water baffle 3 by own weight, and a dewatering rubber 6 is brought into contact with a rolling roll 2. Cooling water 11 flowing from a roll coolant header 10 stays between the baffle 3 and the roll 2 and does not flow under the rubber 6. In the case a sheet temp. is not lower than a certain temp., a large tension is applied to the hanging member 12 to turn the baffle 3 clockwise, so that a gap 32 is generated between the rubber 6 and the roll 2 to flow the water 11 and to cool a contacting part of the roll 2 and a rolled stock 4. Hence, locally staying water and rough surface of the roll 2 do not occur and generation of flaws on the stock 4 is prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a cooling device for a hot rolling mill.

(Prior art and problems to be solved by the invention) Conventionally, hot rolling mills receive a large amount of heat flux from the rolled material during rolling, resulting in rough skin of the rolling rolls due to thermal fatigue and thermal deformation of the rolls. Surface flaws and poor flatness occur on the material. Therefore, a cooling device is required to cool the rolling roll. A conventional rolling roll is disclosed, for example, in Japanese Patent Publication No. 81-61883.

This is a method in which cooling water 11 is directly sprayed onto the surface of the rolling roll 2 by spray 25 during rolling, as shown in FIG. Note that the cooling water shielding plate 26 shields the rolled material 4 from being properly cooled when the leading and trailing ends thereof pass therethrough, and is on standby during other rolling operations to shield the cooling water 11 from the spray 25. Problems with such spray-type cooling equipment include (a) Quality of the rolled material - The problem is that the cooling water that is sprayed and collides with the rolling rolls scatters and causes problems during rolling. As the water falls onto the rolled material and forms a local puddle, the rolled material is locally cooled down, resulting in the generation of residual stress and poor shape (poor flatness, etc.).

(b) Another problem with equipment is that since the sprayer is installed close to the rolling roll, a large amount of spray is required in the longitudinal direction of the rolling roll, which increases equipment costs and prevents the spray from being heated due to the heat of the rolled material. The problem is that white substances such as CaO precipitate, which causes frequent spray clogging and makes maintenance difficult.

To solve these problems, Japanese Patent Application Laid-Open No. 62-613
As shown in FIG. 6 in Publication No. 612, a gap of 28.2 to 5 mm is provided between the rolling roll 4 and the cooling water jacket 27, and the gap is cooled by a closed loop cooling water system 29 using a pump 30 and a heat exchanger 31. There is a method of cooling at a water speed of 5 to 30 m/sec. The problems with such jacket type cooling equipment are: (a) In terms of quality of the rolled material, unlike the spray type, cooling water does not enter between the rolls and the rolled material, so the spray Compared to other types, the surface of the rolling roll is more likely to become rough. This rough surface of the rolling rolls frequently causes mechanical scratches on the rolled material.

(b) Another problem with equipment is that new equipment for a support mechanism for the cooling water jacket, a pump, and a heat exchanger is required, making the equipment cost much higher than for the spray type.

(Means for Solving the Problems) The present invention advantageously solves the problems of the prior art. It consists of a cooling water receiving part that forms an open gutter-like space and a cooling water header that forms a water flow in the space. A thin film of cooling water is formed on the surface of the roll through a small gap between the bottom plate and the roll for cooling. In a cooling device for a hot rolling mill, a cooling water receiver is installed so as to be rotatable around a fulcrum shaft provided parallel to the rolling roll side from the center of gravity axis in the longitudinal direction of the rolling roll. A tension transmission device is provided for suspending the cooling water receiving part to make it freely rotatable, and a tension detector is further provided to detect the actual tension value acting on the tension transmission device, and the actual tension value detected from the tension detector. A cooling device for a hot rolling mill, characterized in that it is also equipped with a tension control device that controls the tension so that the deviation from a preset target tension value is small.

The apparatus of the present invention will be explained in detail below based on the drawings.

(Example) FIG. 1 shows an embodiment of the present invention.

In the hot rolling mill, 1 is a backup roll and 2 is a rolling roll. The cooling water shielding plate 3 is installed in front of the rolling roll 2 with respect to the rolling direction 5 of the material 4 to be rolled. The cooling water shielding plate 3 is usually made of iron or the like with high strength, and especially in the part where it comes into contact with the rolling roll 2, draining rubber 6 is used so as not to damage the rolling roll 2. A fulcrum shaft 8 is provided parallel to the center axis 7 of the cooling water shielding plate 30, which is parallel to the longitudinal direction of the roll 2, and on the roll 2 side. The cooling water shielding plate 3 is rotatable about a fulcrum shaft 8 in a rotating direction 9), and is in contact with the rolling roll 2 due to its own weight when no force is acting on the cooling water shielding plate 3. In this case, the cooling water shielding plate 3
The drainage rubber 6 is in contact with the rolling roll 2 and there is no void.
Cooling water 11 flowing from the roll coolant header 10 stays between the rolling roll 2 and the cooling water shielding plate 3. When no force is acting on the cooling water shielding plate 3, the cooling water shielding plate 3 and the rolling roll 2 are in contact, so the stagnant cooling water 11 leaks under the drainage rubber 6 of the cooling water shielding plate 3. Never. A suspension member 12 such as a wire or chain for suspending the cooling water shielding plate 3 is attached to the center axis 7 of the cooling water shielding plate 3 in the opposite direction to the rolling roll 2, for example, as shown in the figure.

The hanging member 12 is connected to a tension transmitting device 14 via a sprocket 13, and a tension detector 15 is provided in the middle thereof to measure the actual tension value acting on the hanging member 12.

The sprocket 13 is for changing the direction of the hanging member, and the direction 1 connecting the cooling water shielding plate 3 and the sprocket 13 is
Direction 17 in which 6 is connected to the sprocket 13 and the tension transmission device
I am changing it to If there is no need to change the direction, the sprocket 13 is not necessary, and if you want to change the direction in an arbitrary complicated manner, there may be a plurality of sprockets 13.The tension detector 1
5 uses a tensile load transducer type, for example. A specific example of the tension transmission device 14 is shown in FIG.
chain). The rotation of the motor 19 is controlled by the tension control device 18 so that the actual tension value measured by the tension detector 15 becomes a preset tension value. The Celsin 21 is used to detect the rotation angle of the motor 19 and monitor the position of the worm jack 20.

The worm jack 20 converts the rotational motion from the motor 19 into linear motion, and is preferably one that can be finely adjusted by about 1 mm/rotation.

Next, the tension control device 18 will be explained with reference to FIG.

In the target tension selection table 22, target tension values are input according to plate thickness, plate hardness, and plate temperature.For example, when the plate temperature is below a certain level, the target tension value is 0, and when the plate temperature is above a certain value. The target tension value is set to increase as the tension increases, the thickness of the plate increases, and the hardness of the plate decreases.

The tension control unit 23 calculates the deviation between the target tension value and the actual tension value detected by the tension detector 15, and calculates the motor speed command value according to the amount of deviation. Inverter 24
is the motor speed command value of the motor 1 of the tension transmission device 14.
9 to control the speed of the motor.

(Function) The function of roll cooling according to the present invention will be explained in FIG.

In Fig. 4(a), if the plate temperature is below a certain temperature,
For example, when rolling the tip or rear end of the rolled material 4, the tension value applied to the hanging member 12 is set to 0, and the cooling water shielding plate 3
Due to its own weight, a moment (rotation direction 9) in the opposite clockwise direction is applied around the fulcrum shaft 8, and the draining rubber 6 comes into contact with the rolling roll. Therefore, the cooling water 11 flowing from the roll coolant header 10 stays between the cooling water shielding plate 3 and the rolling roll 2, and does not leak below the draining rubber 6. As shown in FIG. 4(b), the cooling water 11 remains at a constant temperature. In the above case, the higher the plate temperature, the thicker the plate, and the higher the hardness of the plate, the greater the tension value is applied to the hanging member 12, and the cooling water shield plate 3 is rotated in the clockwise direction. (rotation direction 9), so a gap 32 is created between the draining rubber 6 and the rolling roll 2. This gap 32 becomes larger as the tension value increases. The cooling water 11 staying between the gaps 32 flows so as to wet the rolling rolls 2 below the draining rubber 6, without creating local puddles on the rolled material, and between the rolling rolls 2 and the rolling material 4. cooling the contact surfaces. The draining rubber 6 is worn out and lost, but if the rotation of the cooling water shielding plate 3 is adjusted by tension, the gap 32 between the draining rubber 6 and the rolling roll 2 can be kept constant regardless of the wear of the draining rubber 6. can be maintained and the desired effect can be obtained.

(Effects of the Invention) The apparatus of the present invention does not create local puddles on the rolled material, unlike the spray type in the prior art, and does not cause roughening of the roll surface, unlike the jacket type. Therefore, it is possible to suppress the occurrence of defects on rolled materials by hot rolling mills to approximately 20% or less compared to conventional equipment, and equipment costs can also be significantly reduced compared to conventional equipment.
There are significant effects such as significantly easier maintenance.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of a tension transmission device in the apparatus of the present invention, FIG. 3 is an explanatory diagram of a tension control device in the present invention, and FIG. 4 is a diagram according to the present invention. An explanatory diagram showing the cooling effect of the rolling roll, (a) is when the tension is 0.
FIG. 5B is a diagram showing the cooling effect when tension is applied, and FIGS. 5 and 6 are schematic diagrams of a device according to the prior art. 1...Backup roll 2...Rolling roll 3...Cooling water receiver 4...
・Rolled material 5... Rolling direction 6... Draining rubber 7... Center of gravity axis 8... Fulcrum axis
9... Rotation direction 10... Roll coolant starter 11... Cooling water 12... Hanging member 13.
...Sprocket 14...Tension transmission device 15...
・Tension detector 16.17...Movement direction of hanging member 18...Tension control device 19...Motor 20...
- Worm jack 21...Celsin 22...Target tension selection table 23...Tension control section 24...Inverter 25
...Spray 26...Cooling water shielding plate 27.
...Cooling water jacket 28...Gap 29...Cooling water system 30.
... Pump 31 ... Heat exchanger 32 ... Gap

Claims (1)

[Scope of Claims] 1. A cooling water receiving part that is provided between the rolling roll to be cooled and forms a gutter-like space that is open at both ends and that is opposite to the roll, and that forms a water flow in the space. A hot heating system in which a part of the roll is immersed in the water flow, and a thin film of cooling water is formed on the roll surface through a small gap between the bottom plate of the cooling water receiver and the roll. In a cooling device for a rolling mill, a cooling water receiving section is installed so as to be rotatable about a fulcrum shaft provided parallel to the rolling roll side from the center of gravity axis in the longitudinal direction of the rolling mill, and the cooling water receiving section is installed on the side opposite to the rolling roll. A tension transmitting device is provided which suspends the receiving part to make it freely rotatable, and a tension detector is provided to detect the actual tension value acting on the tension transmitting device, and the actual tension value detected from the tension detector is installed in advance. A cooling device for a hot rolling mill, characterized in that it is equipped with a tension control device that controls the tension so that the deviation from a set target tension value is small.