JPS58135716A - Continuous descaling equipment of hot rolled sheet - Google Patents

Abstract

PURPOSE:To obtain a continuous descaling equipment of hot rolled steel sheet capable of reducing an installation space and operating highly efficiently, by seqentially arranging devices for working such as scale breaking, acid coating, mechanical descaling, washing, and trimming, in series. CONSTITUTION:A hot rolled steel band A is sent to a cutting device 2 from an uncoiler 1 to cut off an off-gauge part and a malformed part, and then, the tail end of preceding band and the front tip of succeeding one are welded by a welding device 4. Next, the band A is passed through a scale breaking device 5a and successively is coated with an acid by an acid coating device 6a, and then the unreacted acid is removed by an acid removing device 6b. Next, the band is passed through a mechanical descaling device 6c to remove scales. Succesively, the band is washed by a surface washing device 7 and is dried by a dryer 8, then the both side edges of the band are cut off by a trimming device 10 to make its width uniform. Next, the band is coiled up by a coiler 13 after passing through an oiling device 11 and a cutting device 12.

Description

[Detailed description of the invention] The present invention relates to a continuous descaling apparatus for hot rolled steel sheets.

Conventionally, methods for descaling hot rolled steel sheets can be broadly classified into pickling methods and mechanical descaling methods.

Among these, the mechanical descaling method attempts to remove scale using shot blasting, wire brushing, etc., but with normal methods, productivity is low and scale remains or uniform descaling cannot be achieved. It had a rather fatal flaw that it couldn't be done. For this reason, descaling of hot rolled steel sheets has generally been carried out by pickling. A general example of a device for descaling hot-rolled steel sheets by pickling is one with a configuration as shown in Figure 1. A payoff device 1 that unwinds the copper strip into a hot-rolled steel strip, a shear device 2 that cuts off the off-gauge portion and the defective shape portion at the tail end of the leading copper strip, and cuts the off-gauge portion and the defective shape portion at the tip of the trailing steel strip, and A welding device 3 that connects the following steel strip, an inlet achievator device 4, an oxide film on the surface of the copper strip (
A skenyl breaker device 5 that causes cracks in mill scale), a pickling descaling tank 6 that chemically dissolves scale with acid, and a surface cleaning device 7 that washes off acid from the surface of the copper strip after pickling. , a dryer device 8 for drying the surface of the copper strip, an outlet accumulator device 9, a side trimmer device 10, an oiling device 11 for applying oil to the surface of the copper strip, and a shear device for cutting the copper strip after winding it to a certain weight. 12 and a winding device 13. The scale on the surface of the hot-rolled steel strip is dissolved and peeled off in the pickling and descaling tank 6, and a base surface is formed on the copper strip, making it ready for cold rolling.The scale is removed in the pickling and descaling tank 6. The waste acid used in the process is recycled and recycled by an acid recovery device (not shown), which is ancillary equipment, and is recycled and reused. The waste water from the surface cleaning device 7 is cleaned by a water treatment device (not shown) and used for circulation t1.

However, in the conventional equipment as described above, scale is dissolved and peeled off by contact treatment with acid in a pickling tank.
Since it is intended to introduce exfoliated scale into the acid solution, a long pickling tank is required, and furthermore, large-scale equipment is required as a waste acid treatment device. Therefore, it required a large amount of space and cost. Further, when using the above-mentioned apparatus, there is a problem that the time required for pickling becomes extremely long depending on the state of scale formation. Furthermore, since a large amount of acid is used for pickling, each part of the equipment is susceptible to corrosion, and special materials such as corrosion-resistant materials must be used.
In addition, the problem of worsening the working environment arises.The inventors of the present invention have conducted repeated research in view of the above points, and have found that prior to acid treatment, a large number of cracks are formed on the surface of the steel sheet, and then the When the acid is applied and brought into contact for a short time, the acid penetrates through the cracks to the surface of the steel base, dissolves the cracks and the boundaries between the scale and the steel base, but the acid is not strong enough to cause peeling, especially at the boundaries. Dissolution progresses to some extent from the innermost part of the crack along the boundary, and the scale can be lifted off. Such floating scale can be easily removed by mechanical descaling, and an excellent finished surface can be obtained. That is, the object of the present invention is to reduce the installation space and equipment costs, and to provide a hot rolling method that can economically and efficiently remove scales. An object of the present invention is to provide a continuous descaling device for steel strips.

The purpose of the present invention is to provide a device for unwinding a coil after hot rolling into a copper strip, a device for aligning the tail end of a preceding copper strip with the tip of a succeeding copper strip, and a device for connecting both steel strips. , a scale breaking device that creates cracks on the surface of the copper strip, an acid coating device that applies acid to the cracked surface of the copper strip, a mechanical descaling device that removes school, and a scale breaking device that creates cracks on the surface of the copper strip after descaling. equipment for washing and drying the
It consists of a device for cutting both ears of the copper strip to make the same width, and a device for dividing and winding the copper strip after descaling, and is characterized in that each of these devices is arranged in series in sequence. It is also an object of the present invention to provide a device for unwinding a coil after hot rolling into a copper strip, and a device for unwinding a coil after hot rolling into a copper strip, and a device for unwinding a coil after hot rolling to form a copper strip. A device that aligns the ends of the copper strips, a device that connects both copper strips, an accumulator device that continuously sends the copper strips to the subsequent process, a scale breaking device that creates cracks on the surface of the copper strips, and a device that prevents the occurrence of cracks. A device that applies acid to the surface of the copper strip, a mechanical descaling device that removes scale, a device that cleans and dries the surface of the copper strip after descaling, an accumulator device that continuously feeds the copper strip, and a mechanical descaling device that removes scale. The hot rolling method consists of a device for cutting both ears to make the width of the copper band the same, and a device for dividing and winding the copper strip after descaling. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention, which is achieved by a continuous descaling apparatus for steel strips, will now be described in detail with reference to embodiments shown in the drawings.

FIG. 2 shows an embodiment of the continuous descaling device for hot rolled steel sheets according to the present invention. In the descaling device shown in FIG.
The unwinding machine 2, which is equipped with a flat-o etc., unwinds the hot-rolled coil to form a hot-rolled steel strip. A cutting device for cutting the defective part is, for example, an up-cut shear. 3 efficiently connects the tail end of the preceding steel strip and the tip of the following steel strip.

05a, which is a welding device such as a flash barat welder or a flash trimmer, is a scale breaking device that creates cracks on the surface of the hot rolled steel strip. In the present invention, a large number of cracks are generated in the scale using the scale breaking device 5a, and the penetration of acid by the acid cloth in the next step is facilitated and accelerated, which is preferable for later mechanical descaling. Since the purpose is to form a floating state of scale, the scale breaking device adopted in the present invention is designed to prevent a large number of cracks from reaching up to or near the base surface of the copper strip. It is preferable to use a material that can be formed as evenly as possible. Examples of suitable scale breaking devices 5a include a quadruple rolling mill (Fig. 2.3) and a Leherinck mill (g4
Examples include a combination of a roll bender and a double rolling mill (FIG. 4(b)), a combination of a tension leveler and a quadruple rolling mill (FIG. 4(C)), etc. In these devices, the rolling reduction rate is adjusted as appropriate depending on the winding temperature in the rolling process, the use of the steel plate, the presence or absence of a finishing pickling process, etc.
To explain in more detail, when the winding temperature is high, scale is particularly generated at the side edges of the steel sheet, forming a thick scale layer. The rolling reduction ratio is preferably 10 to 15%. Moreover, the preferable rolling reduction rate also differs depending on the use of the product.

If the rolling reduction rate is too high, scale may not only be crimped or wedged into the base metal, making descaling even more difficult, but also cause problems such as deterioration of the surface quality and, in particular, loss of mechanical properties. Therefore, when shipping as a hot-rolled product, for example, the rolling reduction is preferably 2 to 5 inches. On the other hand, in the case of cold-rolled products, the mechanical properties are improved by annealing after cold rolling, so the reduction ratio is preferably 5 to 10% in terms of scale-breaking effect. .

6a is an acid coating device which is a feature of the present invention.

The acid treatment of the present invention does not involve immersing the copper strip in an acid solution to dissolve and remove scale in the acid solution, as in the past, but by applying acid to the surface of the copper strip, cracks can be removed. Since the purpose is to infiltrate the acid and mainly dissolve the boundary film between the cracks and the base metal to float the scale layer, a conventional long pickling tank is not necessary θ Acid coating device preferred for the present invention As for 6a, spray one type (Figure 5 (a)), roll coater type (Figure 5 (b))
There are two methods: a method in which acid is dripped onto a copper strip, and a method in which a porous body is impregnated with acid and brought into contact with a steel plate and applied. Further, a combination of these methods may be used. The acid used in the acid coating device of the present invention may be either hydrochloric acid or sulfuric acid, but hydrochloric acid is preferable in terms of high speed processing and surface finish. The acid concentration is 5 to 15%, preferably about B to 12%. Considering the working environment, the temperature of the acid solution is 50°C.
-95°C, particularly 65-90°C is preferred.

After applying the acid, it takes at least 1 second for the acid to penetrate into the cracks and lift the scale layer, so the line length of the acid application device 6a is determined by the contact time of the acid with the copper strip or After applying the acid, set the time so that it can be left for at least 1 second. On the other hand, since one of the purposes of the present invention is to shorten the line length of the entire descaling device, it is also necessary to suppress the line length of the acid coating device 6a to the minimum necessary length. Therefore, the preferred line length is , the contact time or standing time is 1 to 14 seconds, especially 3 to 1
This is approximately 0 seconds. For example, in the case of ordinary materials, the sheet passing speed is about 500 mpm, the standing time is about 3 seconds, and the pass line length in the acid coating device is about 25 m. In the case of high-temperature materials, the threading speed is approximately 250 mpm.
, the standing time was 10 seconds, and the pass line length in the acid coating device was 4.
It is about 2m.

6b is an acid removal device equipped with, for example, a phosphor, a curl roll, and/or a water washing device, and removes unreacted acid content from the surface of the steel plate.

6c is a mechanical descaling device that mechanically removes the scale layer floating on the steel base. Mechanical descaling devices that can be used in the present invention include those using SOS wire brushes, piano wire wire brushes, nylon brushes, etc., grinding, grinding, doblasting, fluid honing, high-pressure fluid jetting, and iron oxide slurry projection. Examples include methods that perform the following methods. Among these devices, those equipped with a brush roll 21 such as a wire brush and a support roll 22 as shown in FIGS. 2 and 3 are particularly suitable. In this case, the brush pressing force is 0.5. ~2 ton, circumferential speed 500~10
0100O, brush bite amount is 0.5~2.5 xyx
The mechanical descaling device 6c shown in FIG. 0, which has a preferable degree, is provided with two stages of rough passes and one stage of finishing buses. The brush diameter is approximately 400 gm. A water circulation device (not shown) is provided to promote scale removal.

The surface of the copper strip after descaling is cleaned with a conventional surface cleaning device 7, such as a cold water wash, a brush roll and/or a hot water rinse, and dried with a drying device 8, such as an n1 hot air jet. 10 is a normal trimmer device that cuts both sides of the copper strip to make the width the same; 11 is a trimmer device that completely descales the copper strip to prevent rust from forming on the surface of the strip; 13 is a cutting device such as an up-cut shear having the same configuration as the cutting device 2; When the copper strip is removed, the copper strip is cut.The winding machine 13 applies a certain tension to the copper strip, aligns the coil edges, and winds the coil from 4.

In the above-mentioned descaling device, the hot-rolled coil unwound from the unwinding machine 1 becomes the copper strip A and is first sent to the cutting device 2 where off-gauge parts and defective parts at the front and rear ends of the steel strip are removed. Cut and wrap〇Then, the copper strip is put into the welding device 4, and the tail end of the preceding steel strip and the tip of the following steel plate are connected and the copper strip is continuous. The continuous steel strip A is passed through the scale plate tong device 5, causing a large number of cracks in the scale layer on the surface of the steel strip. The surface of the copper strip with cracks and cracks is coated with acid by an acid coating device 6a, for example, by means of through-coating.

After applying the acid, let it stand for at least 1 second, and the master says that by leaving it in contact with the acid for at least 1 second, the acid will penetrate through the cracks and into the interface between the scale and the base steel, dissolving some of the scale on the interface. Creates a condition that lifts the scale layer. After that, using an acid removing device 6b such as a ringer roll,
After unreacted acid adhering to the surface of the copper strip is removed,
The steel strip A is passed between, for example, a brush roller 21 and a support roll 22 of a mechanical descaling device 6c. In this mechanical descaling device 6c, the scale attached to the base metal that is held in a state floating above the base metal and peeled off from the base metal halfway is easily removed by the rotation of the brush roller 21. Sanru. The steel strip A that has been stripped of the scale I is washed in a surface cleaning device 7, then dried in a drying device 8, and then subjected to an operation for adjusting the width in a trimmer device 10, and then oiled in an oiling device 11. After that, winder 1
Wind it up by 3.

FIG. 3 shows another embodiment of the continuous descaling apparatus for hot rolled steel sheets according to the present invention. In this embodiment, in addition to the structure of the embodiment shown in FIG. 2, an inlet side accumulator device 4 consisting of, for example, a loop car is provided between the welding device 3 and the scale breaking device 5a. Even if the threading of the copper strip A is temporarily stopped during welding work in the welding device 3, the accumulator device 4 can be used in the next process.
This is to prevent the supply of steel strip A from being stopped, and enables continuous descaling even during welding work. In this embodiment, a drying device 8 and a trimmer device 1 are further provided.
0, an output accumulator device 9 similar to the input accumulator device 4, for example, a one-loop type, is provided. This device enables continuous descaling even when the line is stopped during copper strip cutting in the post-process, and together with the inlet accumulator device 4, it greatly improves productivity and eliminates off-gauge problems. Contribute to the reduction of

Further, in the embodiment shown in FIGS. 2 and 3, a priddle roll may be provided before and/or after the schedel braking device 5a to apply appropriate tension.

As described above, the present invention does not use a long pickling tank and instead uses a simple acid coating device for acid treatment, so compared to the conventional continuous descaling device using pickling. , the equipment length can be shortened to 115 to 1/2, and the equipment cost can also be reduced. In addition, since the contact time with the acid only needs to be short, the treatment speed of the copper strip was set at 600 m/mv.
This can improve work efficiency. In conventional descaling equipment using pickling, the maximum speed was about 300 m/H. In addition, since it is less affected by acids, corrosion in the valleys of the equipment can be suppressed and the working environment can be improved, and working efficiency can also be improved from this point of view.

Furthermore, since the scale can be lifted to a partially peeled state by acid treatment, the power required for mechanical descaling may be small and the wear and tear on brush rolls and the like is minimal. Moreover, an excellent finished surface can be obtained. Furthermore, it not only does not require a long pickling tank, but also has the advantage that it does not require a large-scale waste acid treatment device because scale is not removed from the acid solution as in the conventional method.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a conventional continuous descaling device by pickling, and FIGS. 4 is a schematic diagram showing a configuration example of a scale breaking device used in the present invention, and FIG. 5 is a schematic diagram showing a configuration example of a scale breaking device used in the present invention.
1 is a schematic diagram showing an example of the configuration of an acid coating device. 1. Rewinding machine 2. Cutting device 3°° welding device 4. Accumulator device 5.5a.. Scale breaking device 6.. Pickling tank 6a.. Acid coating device 6b.. Acid removal device 6c.・Mechanical descaling device 7・・Surface cleaning device 8・・Drying device 9・・Accumulator device 1O・・Trimmer device 11・・・Oiling device 12
... Cutting device 13 ... Winding machine 21 ... Brush roll 22 ... Support roll Fig. 4 (C) 11 Threading Fig. 5

Claims (2)

[Claims] (1) A device that unwinds the coil after hot rolling to form a copper strip, a device that aligns the tail end of the preceding copper strip with the tip of the following copper strip, a device that connects both copper strips, and a device that A steel breaking device that creates cracks on the strip surface, an acid coating device that applies acid to the cracked copper strip surface, a mechanical descaling device that removes scale, and a cleaning and cleaning device that cleans the copper strip surface after descaling. It consists of a drying device, a device for cutting both ears to make the width of the copper strip the same, and a device for dividing and winding the copper strip after descaling, and each of these devices is arranged in series in sequence. A continuous descaling device for hot rolled steel strips. (2) A device for unwinding the coil after hot rolling into a copper strip, a device for aligning the tail end of the preceding copper strip with the tip of the following copper strip, a device for connecting both copper strips, and a device for aligning the tail end of the preceding copper strip with the tip of the following copper strip; An aggulator device that continuously sends the copper strip to the process, a scale breaking device that creates cracks on the surface of the copper strip, a device that applies acid to the surface of the copper strip with cracks, and a mechanical device that removes scale. A scaling device, a device for cleaning and drying the surface of the copper strip after descaling, an accumulator device for continuously feeding the copper strip, and a device for cutting both ends of the copper strip to make the width the same. 1. A continuous descaling device for hot-rolled steel strips, comprising a device for dividing and winding a copper strip after descaling, and each device is arranged in series in sequence.