JPH0459041B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention provides a method for directly contacting the side surface of a hot slab material,
The present invention relates to a method for cooling a press tool that adjusts the width of a hot slab by periodically pressing the side surface of the hot slab.

[Conventional technology]

In recent years, most slab materials for hot rolling have been produced using continuous casting machines (hereinafter referred to as continuous casting machines). However, current continuous casting machines form slab materials through molds and cannot rapidly change the width of the slab, so they have the drawback of not being able to efficiently produce slabs of various widths. Therefore, in order to efficiently produce slabs with various widths, it has been considered to produce slabs with a constant width in a continuous caster and reduce the slab width to the required width in a hot rolling line. Therefore, in hot rolling lines, there is a need for technology that allows for wide range adjustment of strip width.

One technique for reducing slab width is by using vertical mills. Since this method involves rolling down the slab in the width direction using a pair of rolls, it has the following drawbacks.

(1) Thick raised parts called dock bones occur near both ends of the slab in the width direction, and when horizontal rolling is performed in a subsequent horizontal rolling mill, the amount of width return increases.

(2) Because the contact area between the slab and the roll is small, the slab is prone to buckling in the width direction, and it is not possible to significantly reduce the width in one pass, but the width is gradually reduced over several passes. It is necessary to do so.

(3) Crop portions called fishtails occur at the longitudinal end and rear end of the slab, resulting in poor yield.

In addition, as another method of reducing slab width,
-There is one described in Publication No. 68504. This method is called a front-to-back end press method, and after the front and rear ends of the slab are pre-pressed using a pair of press tools that have a tapered or rounded part and a straight part, they are then placed in a vertical rolling mill. Therefore, the slab width is reduced. However, although this method can prevent the above-mentioned lock roll (3), it cannot compensate for the other drawbacks (1) and (2).

Therefore, while continuously moving the slab in the longitudinal direction, the inventors used a pair of press tools having pressing surfaces parallel to the sides of the slab to periodically compress the slab in the width direction, thereby reducing the width of the slab. We devised a press-type slab width reduction method to achieve this (patent application 1983-
No. 209367). According to this method, the raised part of the thickness of the dock bone is closer to the center in the width direction,
And the amount will decrease. Moreover, it is also possible to significantly reduce the slab width. However, even in this method, a tongue-shaped cropped portion called a tongue is generated at the front end and rear end of the slab. Therefore,
In order to compensate for this drawback, the inventors filed a patent application in 1983.
No. 201502 was filed, and by vibrating a pair of opposing press surfaces consisting of a surface parallel to the side surface of the slab and a surface including a radiused portion inclined outward toward the entrance side of the slab with respect to this surface. Through tests, we devised a method to press the sides of the slab to reduce its width, and it was confirmed through tests that it was possible to significantly reduce the crop at the front and rear ends of the slab.

That is, as shown in FIGS. 9 and 10, a hot slab material 10, which is a raw material for rolling, is pressed by a pair of press tools 14 and 16 while being moved intermittently in the longitudinal direction as shown by arrows 12. , to adjust the plate width. The press tools 14 and 16 have parallel parts 14A and 1 whose press surfaces facing the hot slab material 10 are parallel to the side surface of the hot slab material 10, respectively.
6A, and constricted portions 14B and 16B that are inclined so as to gradually separate from the hot slab material 10 toward the entrance side of the hot slab material 10. In addition,
The aperture portions 14B and 16B may have curved surfaces.

The pair of press tools 14 and 16 each vibrate with an amplitude a with an arbitrary period t ₁ + t ₂ , and the plate width
A hot slab material 10 of W ₀ is reduced by ΔW/2 on one side to become a slab material of width W ₁ .

[Problem to be solved by the invention]

By the way, the pair of press tools 14 and 16 are t ₁
The hot slab material 1 is at high temperature for several seconds during the closing operation.
0 to press the hot slab material 10,
The temperature of the press tools 14, 16 gradually increases.
If the temperature is not saturated and exceeds a certain limit (for example, above the tempering temperature of the press tool), when the press tool wears out or cracks occur, the press tool deteriorates significantly and becomes unusable.

On the other hand, when the high-temperature hot slab material 10 is pressed by the press tools 14 and 16, the temperature decreases particularly at the contact portion. The degree of this temperature drop increases as the number of times of contact with the press tool at the same point increases. The greater this temperature drop, the greater the deformation resistance of the slab material.
In addition, there is a temperature distribution in the width direction of the slab material 10, which increases processing energy in later steps such as horizontal rolling, or impedes quality improvement.

From the above, it is very important to prevent the temperature of the hot slab material 10 from decreasing, and while it is desirable to leave the press tools 14 and 16 uncooled if possible, it is necessary to hold the press tools below a certain temperature. There is.

An object of the present invention is to provide a method for cooling a press tool that can cool the press tool with high efficiency while preventing a temperature drop in a hot slab material as much as possible.

[Tools to solve problems]

The press tool cooling method of the present invention periodically presses the side surface of a high-temperature slab material being conveyed to reduce the plate width. In a method for cooling a press tool having a press surface consisting of a parallel part parallel to the side surface of the slab material and a constricted part gradually spaced apart from the slab material toward the entrance side of the slab material, the cooling liquid is applied to the press tool. The coolant is supplied from at least one of the upper and lower directions of the press surface, and the supply angle is such that the coolant hits the tool press surface when the slab material and the press tool are separated.

〔Example〕

As mentioned above, it is necessary to avoid a drop in the temperature of the hot slab material as much as possible. Therefore, the inventors conducted various studies on temperature changes on the press surface of a press tool that presses a hot slab material and methods for cooling this press tool through temperature calculations and experiments. FIG. 8 shows an example of the experimental results. The experimental conditions are as follows:
By the width reduction method shown in Figure 9, the dimensions of the hot slab material are 220 mm thick x 1500 mm wide x 12 m long, and the first
The temperature at the start of the second width reduction was 1150°C, the initial temperature of the press tool was 20°C, and the width reduction of one slab material was completed in 60 seconds. Further, the opening/closing amplitude a of the press tool was 100 mm, and the width reduction amount ΔW/2 of the hot slab material in one press operation was 85 mm. Therefore, the distance between the press surface and the hot slab material when the press tool is opened is 15 mm. Also, the opening/closing cycle of the press tool (t ₁ + t ₂ ) is 0.715×2 sec with t ₁ = t ₂
Assuming that the feed amount of the hot slab sent in t ₂ seconds is 368 mm.
And so.

As shown by the solid line in Figure 8, when the press tool is not cooled, the highest temperature that occurs in the press tool occurs at the surface, at point C where it periodically contacts the slab material, and after the width of the third slab is reduced, the maximum temperature that occurs in the press tool is ~700°C. ℃, which exceeds the allowable operating temperature of the press tool (around 550℃: the tempering temperature of the press tool material). Therefore, as a method of cooling only the press tool without cooling the hot slab material as much as possible, as shown in Fig. 7,
A method of cooling the inside of the press tools 14 and 16 was considered. However, as shown by the broken line in FIG. 8, this effect was not as expected.

On the other hand, during the opening operation of the press tools 14 and 16, the press surfaces of the press tools 14 and 16 are water-cooled (α=
The calculation results for the case of cooling (approximately spraying at about 1000 Kcal/mm ² sec°C) were as shown by the dashed-dotted line in FIG. In this case, the press tool surface temperature after processing three slabs is about ~510°C, and is almost saturated.

From the above study results, it is clear that in order to suppress the temperature rise of the press tool, it is necessary to cool the surface of the press tool where the temperature rises significantly.

Therefore, the inventors developed a method for efficiently cooling the press tool while the press tool is in the opening operation (t ₂ seconds) shown in FIG. 9 on the premise of preventing the temperature drop of the hot slab material 10. Focusing on the fact that the press is separated from the slab material, we devised a method to cool the press surface at this time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an apparatus implementing the press tool cooling method according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 3 is a schematic diagram of a press apparatus equipped with a cooling device according to an embodiment of the present invention. In FIG. 3, a hot slab material 10 is sent to a press device 22 by a pinch roller 20, and a pair of press tools 1
After being pressed in the width direction by 4 and 16, the slab 18 is reduced in width and pulled out by pinch rollers 24. The press tools 14 and 16 are each fitted into a dovetail groove 28 of a tool support 26. The tool support 26 is coupled to a piston 32 of a cylinder 30 and is movable within the housing 34 perpendicular to the direction of slab advancement. Further, the press tools 14 and 16 are provided with engaging portions 36 adjacent to the tool support base 26 on the entrance and exit sides of the slab, respectively, and a crank-shaped fixing hook 38 is provided on the engaging portions 36. is engaged. The fixing hook 38 has an intermediate portion pivotally supported via a pin 40 to a bracket 42 provided on the tool support 26, and a rear end portion pivotally supported via a pin 44 to a piston 48 of a cylinder 46. The cylinder 46 is configured such that the fixing hook 38 can be loosened by introducing hydraulic oil into the oil holes 50 and 52, thereby allowing the fixing hook 38 and the engaging portion 36 to be engaged and disengaged.

The cylinder 30 described above is provided with a position detector 54 and has oil holes 56 and 58 formed therein. Pipes 62 and 64 communicating with a servo valve 60 are connected to the oil holes 56 and 58. The servo valve 60 is connected to an oil tank 66 and a pump 68, and is operated by a command unit 72 via a controller 70 that receives a detection signal from the position detector 54.

The cylinder 30 is fixed to a guide 76 coupled to the screw 74, and
The housing 34 is integrated with the guide 76 as the
move within. The screw 74 is connected to the housing 3
The threaded portion 80 is threaded into a worm wheel 82 provided inside the casing 78 . The worm wheel 82 rotates around the screw 74 as the worm 84 rotates, and moves the screw 74 perpendicularly to the direction in which the slab advances.

Pinch rollers 20 and 24 disposed at the front and rear of the housing 34 are rotatably supported by bearings 86 and 88, respectively, and are connected to drive motors 94 and 96 via reduction gears 90 and 92. The rotational speeds n ₁ and n ₂ of the drive motors 94 and 96 are determined by the command unit 98,
It is given by inputting a finger cooling value of 100 to a motor drive power source (not shown) via the controllers 102 and 104. In addition, drive motors 94, 96
are equipped with tachometers 106 and 108, respectively, to detect the actual rotational speed of the pinch rollers 20 and 24, feed it back to the controllers 102 and 104, and compare it with the command value of the command devices 98 and 100 to ensure that it is always correct. The rotational speeds are set to n ₁ and n ₂ .

The press tools 14 and 16 each have a drawing part 14.
B and 16B have an inclination angle θ of 6 to 20 degrees with respect to parallel parts 14A and 16A, and each vibrates with amplitude a, closing operation time t ₁ second, and opening operation time t ₂ seconds. Then, the hot slab material 10 is pressed into the press tool 1
During the closing operation (t ₁ second) of No. 4, 16, the width on one side is reduced by ΔW/2, and on the other hand, during the opening operation (t ₂ seconds), it is fed in the longitudinal direction by the pinch rollers 20, 22.

As shown in FIG. 1, a bracket 112 for fixing the cooling pipe 110 of the press tools 14 and 16 is attached to the guide 76, and a nozzle 114 with a spray angle α is attached to the tip of the cooling pipe 110. . The cooling pipe 110 is a retractable hose 11
6, and has a structure that can accommodate changes in the slab width _W0 . Further, the cooling pipe 110 is connected to the press tool 14, as shown in FIG.
16, and a plurality of nozzles 114 are arranged along the longitudinal direction.

The position of the guide 76 is set by the screw 74 according to the width of the material slab, so the nozzle 11
The position of No. 4 in the direction perpendicular to the material flow is automatically set, and what remains is the setting of the spray angle α of the nozzle 114. Here, as shown in FIG. 1, the injection angle α of the nozzle 114 is set such that the hot slab material 10 is not hit as much as possible during the opening operation of the press tools 14 and 16, and it is possible to cool the press tool to near the center. Choose as you like.

With this configuration, the press tool 1
Cooling water can be supplied to the press surface during the opening operation of the press tools 14 and 16, and the press tools 14 and 16 can be cooled with high efficiency, and since water does not splash on the hot slab material 10, the temperature drop can be minimized. It can be held to a limit.

FIG. 4 shows that during the closing operation of the press tools 14 and 16,
That is, an example is shown in which a weir 118 is provided to prevent cooling water from flowing out onto the press surface when the press tools 14 and 16 are pressing the hot slab material 10. That is, as shown in the figure, during the opening operation of the press tools 14, 16 (solid line position), the cooling water should not hit the hot slab material 10 as much as possible, and the press tools 14, 16 should have their upper and lower surfaces covered. In addition, the spray is designed to cool the area near the center of the press surface. On the other hand, the press tool 14,
During the closing operation of 16 (double-dashed line position), the cooling water is prevented from directly hitting the hot slab material 10.
However, if the cooling water injected onto the upper and lower surfaces of the press tools 14 and 16 flows out onto the press surface, the temperature of the slab material 10 may drop. Weir 1
18 prevents such outflow and acts to prevent the cooling water from hitting the hot slab material 10 as much as possible, thereby suppressing a drop in temperature of the hot slab material.

If the hot slab material 10 cannot be cooled from above or below, it may be cooled from above or below with a spray angle α' as shown in FIG.

Furthermore, in the embodiment described above, the case was explained in which the cooling pipe 110 having the nozzle 114 was attached to the guide 76 via the bracket 112.
It may be attached to a fixed member, for example, the housing 34, and the nozzle 114 portion may be movable according to the width W ₀ of the raw material slab. Furthermore, as shown in FIG. 6, by attaching the cooling pipe 110 having the nozzle 114 to a fixed member, for example, the housing 34, and rotating the cooling pipe 110 according to the width W ₀ of the raw material slab material, the cooling water can be heated to a hot state. It can also be set so that it does not hit the slab material 10.

There are two methods for injecting the cooling water: one is to inject it only during the opening operation of the press tools 14 and 16, and the other is to inject it all the time.
There are several methods, and the present invention can be applied to either method, but the latter method allows the press tool 14,
It has many advantages such as contributing to the cooling of 16 and simple equipment. However, in the case of the method of constant injection, if the cooling water injected onto the upper and lower surfaces of the press tools 14 and 16 flows out onto the press surface and the temperature of the slab material 10 decreases,
Preferably, a weir 118 as shown in FIG. 4 is provided.

〔Effect of the invention〕

As explained above, according to the present invention, the press tool can be efficiently cooled while preventing the temperature of the hot slab material from decreasing as much as possible.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of an apparatus implementing the press tool cooling method according to the present invention, FIG. 2 is a nozzle arrangement diagram of the embodiment, and FIG. 3 is a press tool cooling apparatus according to the present invention. Fig. 4 is a diagram showing an example of a press tool equipped with a weir to prevent cooling water from flowing out onto the press surface;
6 and 6 are diagrams showing other embodiments of the cooling method for a press device according to the present invention, FIG. 7 is a diagram showing an example of internally cooling a press tool, and FIG. 8 is a comparison of cooling effects of a press tool. 9 and 10 are explanatory diagrams of a method for reducing the width of a slab material using a pair of press tools. 10... Hot slab material, 14, 16... Press tool, 14A, 16A... Plane part, 14B, 16
B... Throttle section, 110... Cooling pipe, 112...
Bracket, 114... Nozzle, 116... Hose, 118... Weir.

Claims (1)

[Scope of Claims] 1. The device is placed on the side of the high-temperature slab material being conveyed in order to reduce its width by periodically pressing the side surface of the slab material, and the surface facing the slab material is the slab material. In a method for cooling a press tool having a press surface consisting of a parallel part parallel to the side surface of the press tool and a constricted part gradually spaced apart from the slab material toward the entrance side of the slab material, the coolant is applied to the press surface of the press tool. A method for cooling a press tool, characterized in that the cooling liquid is supplied from at least one of the upper and lower directions of the press tool, and the supply angle is such that the coolant hits the press surface of the tool when the slab material and the press tool are separated. 2. The press according to claim 1, wherein the supply of the coolant prevents the coolant from flowing out to the press surface when the press tool presses the slab material. How to cool tools.