JPS63183714A - Hot rolling line - Google Patents

Abstract

PURPOSE:To roll the product having no scale defect by a hot rolling mill by constraining the drop of a surface temp. by forming a scale removing means with three piece roller, brush roller and low pressure jet unit. CONSTITUTION:The steel stock temp. of a thin slab casting machine is about 1200-1250 deg.C and 1050-1100 deg.C are necessary at the biting time of a rolling mill but the conventional high pressure water descaling device can not be used because of its reducing the temp. A descaling means is therefore composed of the three piece roller 7 causing a crack on a scale by giving a bend on the surface of the steel stock, the brush roller 8 developping and peeling off the crack and the low pressure jet unit 9 removing the scale by spraying a water thereon. As a result the reduction in the surface temp. of the steel stock can be restrained and the necessary rolling temp. is secured to roll the steel stock having no scale defect by a hot rolling mill.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a hot rolling line.

[Conventional technology]

Conventionally, as described in Japanese Utility Model Publication No. 61-24329, the thickness of the continuously cast slab is thick, and hot rolling is comprised of a rough rolling mill group and a finishing rolling mill group.

Then, in front of the roughing roll or finishing roll, high-pressure jet water of about 120 to 150 kg/a# is sprayed onto the surface of the transported steel material via a high-pressure descaling header to blow away the scale on the surface of the steel material. ing.

However, in order to remove scale firmly attached to the surface of steel materials using high-pressure water jets, there is a problem in that a large amount of electricity is required to drive the pump that increases the water pressure, and a large amount of water is required to spray the water. have. Furthermore, since a large amount of water is injected onto the surface of the steel material, the surface temperature of the steel material naturally decreases. Moreover, is it possible to completely remove scale firmly attached to the steel surface with just high-pressure water injection? There is a problem in which it is difficult to say that removing the particles is sufficient. A brush roll is placed further in front of the main header for high-pressure descaling that sprays high-pressure water, and by pressing the brush roll, a fine rack is generated on the scale on the surface of the steel material.

The idea is to use a subsequent high-pressure water jet to remove residual scale that has cracked in the previous stage and is likely to peel off, and to scatter the scale from the side using a cleaning header.

However, in both of these methods, a large amount of high-pressure water is injected onto the surface of the steel material, so a drop in the surface temperature of the steel material is inevitable. However, there are problems in adopting such conventional descaling methods.

[Problem that the invention attempts to solve]

The above conventional technology does not take into account the fact that the surface temperature of the steel material is lowered by injecting a large amount of high-pressure water.
There were problems in applying a similar device to a rolling line directly connected to continuous casting of thin slabs.

The present invention was made in view of the above points, and it suppresses the low surface temperature of the steel material fed from a continuous thin slab caster, removes surface scale, and rolls it with a hot rolling machine to eliminate scale defects. The object of the present invention is to provide a hot rolling line that has the ability to produce products free of oxidation.

[Means for solving problems]

The above purpose is to provide a scale removing means with three rollers that apply bending force to the surface of the steel material and generate cracks in the scale on one surface, and a brush roller that presses the surface of the steel material to develop and peel off cracks in the scale on the surface. This is accomplished by spraying water onto the peeled scale adhering to the surface of the steel material using a low-pressure jet unit to remove it.

[Effect]

The speed of the steel material cast by the thin slab continuous caster is about 15 to 20 m/sin, which is slower than conventional methods. Furthermore, the temperature of the steel material ranges from 125°C to about 1200°C, and it is necessary to maintain a temperature of about 1100 to 1050°C when it is bitten in a rolling mill. As described above, the conveyance speed is slow and scale is likely to occur, so strong descaling is required. However, in the present invention, the steel material is first passed through three rollers at different positions at different levels, and bending force is applied to the surface of the steel material. Cracks are generated in the scale on the surface. Next, a brush roller is used to further refine the cracks and peel them off from the surface of the steel material. The peeled off scale adhering to the surface of the steel material was collected from the surface of the steel material using a low pressure jet unit.
The scale is removed in a short time, and the steel material can be sent to the hot rolling mill while suppressing a drop in its surface temperature and ensuring the required temperature.

Therefore, steel products without scale defects can be manufactured by rolling high-temperature steel products with a hot rolling mill.

〔Example〕

The present invention will be explained below based on the embodiment shown in the drawing. One embodiment of the present invention is illustrated in FIGS. 1 to 3.

As shown in the figure, the steel material 2 discharged from the continuous caster 1 is hot-rolled in a hot rolling mill 3 at the front stage and a hot rolling mill 4 at the trailing stage, passes through a cooling tank 5, and is sent to a winding machine 6. It is wound up. In the hot rolling line configured as described above, in this embodiment, the hot rolling mill 3,
The scale removing means for removing scale on the surface of the steel material provided on the entry side of the roller 7.7a is a three roller 7.7a that applies bending force to the surface of the steel material and generates cracks in the scale on the surface.
, a brush roller 8.8a that presses the surface of the steel material to develop and peel off scale cracks on the surface, and a steel material 2 that peels off.
The scale was formed using low-pressure jet units 9 and 9a for spraying and removing water from the scale adhering to the surface. By doing this, the scale on the surface of the steel material can be removed while suppressing the temperature drop on the surface of the steel material, thereby suppressing the drop in the surface temperature of the steel material 2 fed from the continuous thin slab caster,
It is possible to obtain a hot rolling line capable of removing surface scale and rolling with the hot rolling mills 3 and 4 to produce products free of scale defects.

That is, the scale removing means is formed by three rollers 7.7a, a brush roller 8.8a, and a low-pressure jet unit 9.9a, and among these, the low-pressure jet unit 9 is formed so as to be able to move toward and away from the steel material 2.

On the exit side, door opening/closing 10, 10a, 11. lla, this entrance, exit side upper and lower opening/closing doors 10+ l Oa, l 1111
It is installed between a and sprays low-pressure water onto the steel material 2.

For blowing off scale adhering to the surface of steel materials.

A dosing header 12, 12a was formed with upper and lower spiral drums 13, 13a for collecting the blown scale. On the entrance side of the low-pressure jet unit 9, upper and lower entrance doors 510 and 10a are provided, which can be opened and closed by cylinders 14 and 14a for the entrance upper and lower opening doors.
Make sure that the ends of the lower opening/closing doors 10°10a touch and close, and when there is no steel material 2, as shown by the two-dot chain line in the second time, the upper and lower opening/closing doors 10, 10a on the entrance side are closed. The tip is steel 2
The steel material 2 is opened without contacting the steel material 2, making it easy for the steel material 2 to pass through. On the exit side, open/close door 11. lla is also on the entrance side, opening and closing 51
0. It is configured to have the same function as LOa, and can be opened and closed by cylinders 15 and 15a for the upper and lower opening and closing doors on the exit side. The low pressure jet unit 9a is also exactly the same.

Entrance side upper and lower opening/closing doors 10, 10a and exit side upper and lower σn closing doors 1
1. Upper and lower spiral drums 13 and 13a and low pressure upper and lower headers 12 and 12a are disposed between the upper and lower spiral drums 13 and 13a. Up,
The spiral drums 13.13a are connected and are provided with scale discharge ports at both ends, as shown in FIG.

The low-pressure jets ejected from the upper and lower headers 12 and 12a collide with the steel material 2, roll up scale on the surface of the steel material 2, and transport it to the scale discharge ports of the upper and lower spiral drums 13 and 13a. Although the low-pressure jet may be water, steam, or gas such as nitrogen gas, the case of water will be described in this embodiment.

The small areas where low-pressure water jetted from the upper and lower headers 12 and 12a collide with the steel material 2 are shown on the inlet and outlet sides.

The tips of the doors L 0 , 10 a , 11 , 11 a are formed by contacting the steel material 2 to prevent them from coming into contact with low-pressure water for a long time, and the steel material 2 is connected to the front and rear hot rolling mills 3 . , 4. Do not bring in low-pressure water. The injected low-pressure water entrains the scale adhering to the surface of the steel material 2 in the form of cracks or peeled off cracks, and is guided to the scale discharge ports of the upper and lower spiral drums 13, 13a, and then the upper and lower spiral drums 13 and 13a are heated.

The water is discharged to the outside from drain pipes on the sides of the swirl drums 13, 13a.

By doing this, the following can be done. The steel material 2 cast by the continuous casting machine 1 is heated to about 120
The three rollers reach the roller 7 at about 0°C. Then, as shown in Fig. 2, the steel material 2 is passed between the three rollers 7, a bending force is applied to the surface of the steel material 2, and the low temperature of the steel material 2 is centered on the scale fixed on the surface. Cracks are generated while being suppressed. Then, a brush roller 8 is used to make the cracks finer and peel them off. The brush roller 8 is driven by a motor (not shown) either in the direction of transport of the steel material 2 or in the opposite direction at a speed faster than the transport speed of the steel material 2.

In the next low pressure jet unit 9, the upper header 12
, 12a is sprayed onto the scale that has adhered to the surface of the steel material 2 in the form of cracks.

The scale is rolled up and conveyed to the discharge ports of the spiral drums 13 and 13a, and the scale is discharged to the outside.

In this case, the entrance, exit upper and lower opening/closing doors 10, 10a.

11.Since it is isolated from the outside by lla, scale will not scatter to the outside, and since the part that comes into contact with low-pressure water is made into a small area as mentioned above, the temperature drop in the steel material 2 is small. Furthermore, since it is close to the rolling mill stand,
The amount of scale generated from this part is very small. Therefore, the steel material 2 from which scale has been sufficiently removed can be fed into the hot rolling mill 3 while ensuring the required temperature. The steel material 2 is also applied to the hot rolling mill 4 in the latter stage using the same procedure as the hot rolling mill 3 in the preceding stage.
can be sent.

As described above, according to this embodiment, it is possible to strongly remove surface scale while suppressing a decrease in the surface temperature of the steel material 2 that is conveyed at a low speed, and the steel material 2 having the required temperature is transferred to the hot rolling mill 3. 4, it is possible to manufacture products without scale defects after hot rolling. In addition, since large amounts of high-pressure water are not used for scale removal as in the past, power consumption can be reduced to a few percent or less compared to conventional methods, and since rolling can be performed at high temperatures, high pressure is possible, which increases the number of rolling mill stands. reduction, energy-saving rolling became I31 function, and installation 4n
It is possible to provide an economically effective hot rolling line that can reduce costs and operating costs.

〔Effect of the invention〕

As mentioned above, the present invention suppresses the drop in the surface temperature of the steel material fed from the continuous thin slab caster, removes surface scale, and enables products without scale defects to be manufactured by rolling it in a hot rolling mill. This technology suppresses the drop in surface temperature of the steel material fed from the continuous thin slab caster, removes surface scale, and enables the manufacture of products without scale defects by rolling in the hot rolling mill. Inter-rolling line can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view of an embodiment of the hot rolling line of the present invention;
FIG. 2 is a longitudinal sectional side view of a low-pressure jet unit according to another embodiment, and FIG. 3 is a sectional view taken along line A--A in FIG. 2. 2... Steel material, 3... Hot rolling mill (first stage), 4...
Hot rolling mill (second stage)? , 7a...3 rollers, 8,
8a...Brush roller, 9,9a...Low pressure jet unit, 10...Inlet side upper opening/closing door, 10a...Entering side upper opening/closing door, 11...Outlet side upper opening/closing door, 11a... Output side lower opening/closing door, 12... Upper header, 12a... Top header, 13... Upper spiral drum, 13a... Lower spiral drum.

Claims (1)

[Claims] 1. In a hot rolling line in which a scale removing means for removing scale from the surface of the steel material is provided on the entry side of the hot rolling mill, the scale removing means is used to apply bending force to the surface of the steel material. 3 rollers that apply pressure to the steel surface to generate cracks in the scale, a brush roller that presses the surface of the steel material to develop and peel off cracks in the surface scale, and a spray roller that sprays water on the scale that has peeled off and adhered to the surface of the steel material. A hot rolling line characterized in that it is formed by a low-pressure jet unit that removes. 2. The low-pressure jet unit is provided between the upper and lower opening/closing doors on the inlet and outlet sides that are formed on the steel material so as to be able to freely approach and separate, and the upper and lower opening and closing doors on the entrance and exit sides, and supplies low-pressure water to the steel material. Claim 1, which is formed by upper and lower headers for blowing off scale adhering to the surface of steel materials, and upper and lower spiral drums for collecting the blown off scale. hot rolling line. 3. The hot rolling line according to claim 1, wherein a descaling device combining at least two of the three rollers, a brush roller, and a low pressure jet unit is provided between the hot rolling mills.