JPS5820316A - Descaling device for hot rolled strip - Google Patents

Abstract

PURPOSE:To remove scale cheaply and securely without damaging a mother material by immersing the material in to a acidic liquid to remove scales with a finishing brush after removing firstly the most of the scales through mechanical descaling. CONSTITUTION:A strip 1 under high-tension conditions generates cracks in the scale layer thereof by a roll mill 2, and then the most part of the scale layer is removed by brush rollers 18a-18d of a mechanical descaling device 3. Nextly, in a chemical descaling device 4, the strip 1 is subjected to pickling, wherein an acidic liquid in the surface layer of the strip 1 reaches the inner parts of the scale layer through the cracks. Then the strip 1 is immersed in a neutralizing tank 5 to be neutralized, and again is removed of the remaining scales by brush rollers 26a-26d of a finishing descaling device 6. The affinity of the remaining scales to the mother material is reduced and the scales are separated from the mother material with ease.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a descaling device for removing scale (rust) from the surface of hot rolled (hereinafter simply referred to as hot rolled) strip.

Conventionally, descaling methods for strips after hot rolling generally include (1) a chemical method using pickling, and (2) a mechanical method such as brushing or high-pressure water jetting. .

However, the former pickling method requires, for example, 40%
It takes a long time, like seconds. For this reason, the length of the pickling tank becomes enormous. For example, if the strip processing speed (traveling speed) is 200 m/rm, the total length of the tank will increase to around 135 m. In addition, the pickling process requires complete dissolution of scale, which takes a long time and generates a large amount of waste such as iron oxide salts.
This is not desirable from the standpoint of pollution prevention.

In addition, the latter mechanical treatment method is relatively simple and can only achieve a scale removal rate of about 90% due to the unevenness of the strip surface or the non-uniformity of the scale remover with respect to the strip. ) requires a large amount of power. - For example, a high-pressure water injection device that injects a plast solution containing an abrasive onto the strip surface requires several thousand kilowatts of power. Furthermore, a brushing device that scrubs the strip surface by rotating brushes requires about 20 sets of rolled brushes, which increases not only the power but also the size of the device.

In addition, the mechanical processing method also improves the unevenness of the strip surface.
Due to the non-uniform thickness of the scale layer, a part of the base material is constantly ground and a Tift Shear phenomenon occurs in which strips are lost, as well as dents and scale remaining in thick scale parts, which reduces quality reliability. It became clear from the test results that the

Therefore, an object of the present invention is to provide a descaling device that can completely remove scale without damaging the base material.

Another object of the present invention is to provide a descaling device that is highly productive and can be manufactured at low cost.

Another object of the present invention is to provide an energy-saving descaling device that has small equipment and small power.

Furthermore, another object of the present invention is to provide a pollution-preventive descaling device that produces less waste material.

In order to achieve such an object, the present invention includes a transfer mechanism for moving a hot-rolled strip, a mechanical descaling device, a chemical descaling device, and a finishing mechanical descaling device along the moving direction of the strip. Scaling devices are installed in sequence, first removing most of the scale on the surface of the systrip by mechanical descaling, then moistening the scale remaining in this process with an acid solution, and finally using a finishing μ brush to remove the scale from the acid solution. It completely removes scale after it has been wetted with water.

The present invention will be explained below with reference to Examples.

FIG. 1 is a schematic diagram showing a preferred example of the descaling device of the present invention. The strip 1 after hot rolling is passed through a number of rolls,
It is moved from left to right in the figure by a transport mechanism such as 4-2. Along this moving direction, a rolling mill 2, a mechanical descaling device 3, a chemical descaling device 4, a neutralization tank 5, and a finishing mechanical descaling device 6 are sequentially arranged, and the strip 1 is processed by each of these devices. Passes through the processing section. The processing speed of this strip 1 is io
om/-. In addition, the strip 1 is used in the pressure cal descaling device 3 and the finishing mechanical descaling device 6.
Since it is necessary to maintain a high tension state, prydles 7 to 10 are disposed at the front and rear of each. In other words?
Prydle 7 consisting of roller groups a to 7d, and 8a to 8
The strip 1 passing through the rolling mill 2 and the mechanical descaling device 3 is made into a high tension field by the prydle 8 consisting of a group of rollers d. In addition, two rollers 9M, 9
b and two rollers 10a.

10b, the strip 1 passing through the finishing mechanical descaling 6 is placed in a high tension state so that the processing effect is sufficient.

Furthermore, the strip 1 is fed by each guide roller 11 to 14 to the next group of devices, such as a mechanical descaling device 3, a chemical descaling device 4, a neutralization tank 5, and a priddle 9.゛The rolling mill 2 has roll groups 15ax 15G, 16a to 116C.
A crack is generated in the scale on the surface of the strip 1 by the positive arc of . This is to improve the effects of subsequent mechanical descaling and subsequent chemical descaling.

Mechanical descaling device 3 has 4 songs with roller 1
7a to 17d, and push rollers 18a to 18d, which are in contact with the curved rollers 17a to 17d, and which rub the moving strip IK. Most of the scale is removed by these brush rollers 18a to 18d. This brush roller 18a~
In the drawing, the number of sets of 18d is two sets each on the upper and lower sides, but this number increases or decreases depending on the processing speed of the strip. If the normal processing speed is 100 m/- as in this example, the flow shown in this figure will suffice, but if the processing speed is 200 m/-, then the
Double the number of pairs will be provided.

The chemical descaling device 4 includes a tank 20 containing an acid solution 19 such as hydrochloric acid or sulfuric acid, and this tank 2.
The strip 1 is disposed in the 0, is fed in by the guide 4-212, and is fed out by the guide roller 13.
A pair of rows (21a, g) immersed in the acid solution 19
It consists of lb. Further, the length of the tank 20 is designed so that the pickling time is approximately 5 seconds.

The neutralization tank 5 consists of a tank 23 containing an alkaline neutralization liquid 22 as described above, and a pair of rollers 24a and 24b for guiding the strip 1 into the neutralization liquid 22, and the neutralization processing time is approximately ' Determine the tank size so that the time is 2.5 seconds.

Finishing mechanical descaling for the final process - The device 6 has a brushing structure similar to the mechanical descaling device 3, and has four sets of bending rollers 25a to 25.
．． d and P5 shielders 26a to 26d. This number of sets is the mechanical descaling device 3.
Similarly, it increases or decreases depending on the processing speed.

Next, strip descaling will be explained. After the slip 1 in a high tension state is covered with scales in the rolling mill 2, most of the scales are removed by the brush rollers 18a to 18dK of the mechanical descaling device 3. Thereafter, it is pickled in the chemical descaling device 4. In the surface layer of the strip '1, as shown in FIG.
covered? The scale layer 28 is formed by rolling with a rolling mill 2 or by rubbing with brush rollers 18a to 18dtC. Rack 29 has occurred. Then, the acid solution reaches the depths of the scale layer 28 through this crack 29. The scale layer 28 has F e and O in the surface layer.

It consists of a layer 30 and an innermost 260 layer 31.

Fe in the surface layer: 0. Layer 30 is difficult to etch (etch), but 260 layer 31 in contact with base material 27 is easily etched. As a result, the erosion holes 32 are electrically distributed along the surface direction of the base material 27. Therefore, in the pickling process, it is not necessary to completely dissolve the entire scale layer, and if some erosion holes 32 are formed, -R-kale can be completely removed in the subsequent final mechanical descaling process. Therefore, the pickling treatment time can be shortened to about 5 seconds instead of the conventional 40 seconds. Next, after the strip 1 is immersed in the neutralization tank 5 for 25 seconds to be neutralized, the remaining scale is removed again using the brush rollers 26a to 26d of the finishing mechanical descaling device 6. The remaining scale is removed from the base material 2 by pickling.
Since the adhesive strength with 7 is low, it can be peeled off from the base material 27 very easily with a brush.

According to such an embodiment, after most of the scale is removed by the first mechanical descaling, the remaining scale is etched by the chemical descaling and the bonding force with the base material is weakened, and then the second finishing is performed. Since mechanical descaling is performed, even if the strip surface is uneven or the thickness of the scale layer varies, the scale can be completely removed without damaging the base material, improving quality. You can also use the desk as
In this embodiment, chemical descaling is performed between two mechanical descalings, so the overall working time is shortened and productivity is improved. Furthermore, the number of sets of brush rollers is at least as large as that of the conventional method, and the power consumption can be reduced, and the length of the tank of the chemical descaling device can also be reduced by at least 4 times. For example, even if the strip O moving speed is 200 m/-, which is twice that in the example, the tank length is sufficient to be about 25 m.

Therefore, the total length of the device in this embodiment is longer than that of the conventional device! 00
It can be about m00m.

In addition, since the chemical descaling device requires a shorter processing time than conventional methods, the time required to dissolve the scale is shortened, and the generation of iron oxide salts, which become waste products, is also reduced.

As a result, the treatment becomes easy, and the occurrence of pollution can also be prevented.

Furthermore, this embodiment has high productivity, low power consumption, and low acid consumption because the tank is small.
Since the number of brush rollers is small, maintenance costs for the brush rollers are low, and waste disposal costs are low, descaling costs can be significantly reduced compared to conventional methods.

'It should be noted that the present invention is not limited to the above-mentioned embodiments, and modifications can be made based on the technical idea of the present invention. For example, the mechanical descaling device may be a high-pressure water injection device that sprays an abrasive to remove scale.

As described above, according to the descaling device of the present invention,
Scale can be removed inexpensively and reliably without damaging the strip base material.

Furthermore, the device of the present invention is small and does not require much installation space, and consumes less energy and equipment.

Furthermore, the apparatus of the present invention has many effects such as less waste and prevention of pollution.

[Brief explanation of drawings]

FIG. 1 is a schematic view showing a descaling apparatus for hot rolled strip according to an embodiment of the present invention, and FIG. 2 is a partially enlarged sectional view similarly showing a chemical descaling state.

Claims (1)

[Claims] 1. A transfer mechanism for moving the hot-rolled strip, a mechanical descaling device, a chemical descaling device, and a finishing mechanical descaling device are sequentially installed along the strip movement direction, and each device s) A descaling device for hot rolled strip, characterized in that it removes scale from the surface of an IJ tube.