JPH089058B2 - Method of treating strip-shaped metal body with excellent surface properties - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a strip having excellent surface properties.
The present invention relates to a method for treating a metal body. In particular, when removing surface scales and surface flaws generated in the hot rolling process and the continuous casting process of thin cast slabs, it is necessary to improve the surface quality of the strip-shaped metal body, and to simplify the pickling treatment and the surface flaw removal process in another line. The present invention relates to a method for treating a strip-shaped metal body that enables the above-described processing . In the present invention, the band-shaped metal body is stainless steel.
It means a hot-rolled sheet (strip) or coil produced by a usual method of steel, titanium and its alloys, high alloys, etc. , or a sheet (strip) produced by continuous casting to a thin wall, or a coil wound up.

[0002]

2. Description of the Related Art In a manufacturing process of a strip-shaped metal body, an oxide scale and surface flaws are formed on the surface of the strip-shaped metal body due to heating of a slab and subsequent hot rolling or continuous casting of a thin cast slab. And a process for finishing the surface is required. Conventionally, these methods include shot blasting in which a steel ball having a diameter of 0.2 to 0.6 mm is projected on the surface of a strip-shaped metal body to perform surface layer cleaning to cause cracks and peeling of the scale, and then the nitrofluoride. Descale by pickling with acid, sulfuric acid, hydrochloric acid, etc., and then perform cold rolling to correct the shape of the strip metal body, and then remove the surface flaws of the strip metal body by belt grinding on another line. It was regarded as a typical method.

However, in this conventional process, the pickling process is a continuous line with the annealing process, and the grinding line and the rolling line or the dummy plate (leader) welding line are arranged separately, so that the strip metal body In order to remove the oxide scale and surface defects, it is necessary to pass 2 to 4 lines, and there is a problem that the efficiency is extremely poor. An annealing pickling line is inefficient because descaling is performed by pickling, and there are various problems in terms of productivity, cost, and labor saving, such as generation of a large amount of waste liquid due to pickling. . On the other hand, in order to uniformly remove surface flaws by belt grinding in the strip width direction, it is necessary to flatten the shape of the coil by cold working.However, this straightening work may be performed using a normal cold rolling mill. For that reason, in addition to the original gauge down (thickness reduction) work, an additional shape correction work has to be performed, so that there is a problem that not only the efficiency is improved but also the cost is increased. Furthermore, in the grinding line, the method of grinding the surface of the strip-shaped metal body with a rotating endless belt is the main method, but this method requires a low belt passing speed and a short belt life, requiring frequent belt replacement. The sex is bad. In addition, there is a problem that uniform grinding cannot be performed unless the plate shape before grinding is flat.

Therefore, in order to improve the descaling efficiency and the surface quality of the hot-rolled steel strip, a plurality of pickling treatment steps are provided after the pretreatment step including the tension leveler, and the plurality of pickling treatment steps are performed. JP-A-59-41482 discloses a descaling line in which a grinding step for mainly removing metal residues and smut is combined. However, the descaling line improves the surface quality of the steel strip to some extent, but its effect is limited, and since most of the descaling is performed by pickling, a considerably large-scale pickling equipment is required. Therefore, the initial investment is large, and a large amount of waste liquid accompanying large-scale pickling must be treated. Further, since the grinding process provided between each pickling treatment process is not for actively removing the surface flaws of the steel strip, the steel strip passed through the descaling line is used for removing the surface flaws. The problem arises that the plate has to be passed to another grinding line.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems and improves the surface quality of the strip-shaped metal body when removing the surface scale and surface flaws of the strip-shaped metal body. Mechanical descaling and surface conditioning, which can simplify the pickling process and surface flaw removal process, improve the efficiency of the processing work and reduce the manufacturing cost and pollution control by simplifying the acid and waste liquid processing. It is an object of the present invention to provide a method for treating a strip-shaped metal body that does not require a flaw removal work in another line by further reducing the investment and improving the working environment.

[0006]

The present invention has been completed as a result of various studies on mechanical descaling and surface conditioning methods and combinations of the methods in order to achieve this object. In the processing line for removing the flaw and the flaw, the surface layer portion of the strip-shaped metal body having a scale on the surface is set in the range of # 40 to # 400.
And blast with ultra-high pressure water containing an abrasive consisting of, subsequently to conditioning the blast surface by mechanical means, the conditioning subsequent if necessary
The surface roughness before cold rolling to Rmax ≤ 10 μm, and then
The main point is cold rolling . In the present invention, the size of the abrasive grains contained in the ultrahigh pressure water is selected from the range of # 40 to # 400 . Further, it is preferable that the conditioning is performed by disposing a stand in which a pressing roll facing the elastic grindstone roll is a pair. At this time, the abrasive grain count of the elastic grindstone is # 8
It can be selected from the range of 0 to # 600. The polishing treatment with ultra-high pressure water containing abrasive grains may be carried out in multiple stages.

The conditioning performed after the conditioning by mechanical means is blasting with high-pressure water, and the projection pressure used for this is 100 kgf / cm ^2.
It is preferable to carry out the above, and it is preferable to carry out the fusing treatment by light pickling, and in this case, the fusing amount is preferably 0.1 to 30 μm.

In the present invention, as a pretreatment, trimming or grinding treatment of the edge of the strip-shaped metal body is performed, and then the surface scale is modified and cracked if necessary.
Alternatively, heat treatment or cooling treatment that causes peeling may be performed.
Yes . Further, depending on the band-shaped metal body, connecting a leader and continuously threading is also included.

[0009]

The method for treating a strip-shaped metal body according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic explanatory view showing one embodiment of a process line for carrying out the method of the present invention. In the figure, 1 is the rewinding of the strip metal body.
Payoff reels to be supplied as 2 are for hot-rolling or continuously casting thin-walled slabs for strip-shaped metal bodies, 3 for welding dummy plates (hereinafter referred to as leaders) to the strip-shaped metal bodies and welding between leaders. , A submerged arc welder, a TIG welder, a plasma welder, a spot welder, or the like. 4 is a trimmer that cuts and removes edge flaws and hot cracks that occur in the strip-shaped metal body during hot rolling or continuous casting of thin slabs, and 5 is a grinder that removes relatively small of these flaws and cracks. It is an edge grinder for doing. Reference numeral 6 denotes a heating furnace which is installed if necessary to heat the strip-shaped metal body, and a heating furnace for burning heavy oil or gas is usually used, but an electric heating furnace such as induction heating or direct current heating can also be used. Good. Reference numeral 7 is a cooling zone for cooling the strip-shaped metal body after heating, such as gas cooling, spray cooling, water spray cooling, roll cooling and the like. Each of the above devices is a preprocessing unit in the present invention, and may be arranged as necessary.

Reference numeral 8 is a leveler for bending or pulling the strip-shaped metal body. Reference numerals 9 and 10 are ultra-high pressure water jetting devices which grind away the scale of the strip-shaped metal body 1 and perform heavy grinding to remove surface flaws, 9 is the front side of the metal body, and 10 is the back side. , And nozzles 9a and 10a for injecting abrasive grains together with ultra-high pressure water. Reference numeral 11 is a bridle roll for applying a tension necessary for grinding the strip-shaped metal body.

Reference numeral 12 denotes an in-line grinding apparatus for conditioning the front and back surfaces of the strip-shaped metal body . For example, the elastic grindstone roll 12a and the pressing roll 12b each have a plurality of stands arranged in pairs, and the heavy-grinded strip-shaped metal body is arranged. Adjust both the front and back sides of the so that they are smooth. The elastic whetstone roll referred to here is a roll-shaped whetstone having a certain degree of elasticity in order to easily fit to the shape of the plate, for example, a roll formed by laminating discs coated with abrasive grains ( There are a laminated type), a type in which flap wheels are laminated and formed into a roll shape (flap type), and a nylon resin containing abrasive grains integrally formed in a roll shape (integrated type), and the like, and any of these can be adopted. The arrangement of the stand is not particularly limited, but a laminated elastic grindstone roll is placed in the front stage, and the abrasive grain count is large on the final stand side, for example, # 2.
It is preferable to use an elastic whetstone roll of 40 or more.

A cleaning device 13 is installed after the grinding device and performs degreasing, dust removal, and the like. For example, a brush roll 13
a and the press roll 13b are arranged in a plurality of stands, respectively, or a pair of brush rolls are provided so that the front and back surfaces of the strip-shaped metal body face each other. This brush roll includes, for example, a roll made of a brush made of nylon fiber containing abrasive grains. Further hot water spray 13c
Is placed after the degreasing device.

Reference numeral 14 denotes a light pickling apparatus, which performs pickling treatment for adjusting the amount of surface ablation to 0.1 to 30 μm in order to remove burrs and the like generated during the heavy grinding. Reference numeral 15 is a cleaning device, for example, a brush roll 15a
The pressing roll 15b and the pressing roll 15b form a pair of stands, or brush rolls are provided so that the front and back surfaces of the strip-shaped metal body face each other. Further, the hot water sprayer 15c is arranged after the degreasing device. Reference numeral 16 is a tension reel for winding the strip-shaped metal body.

In the processing line having such a structure, the band-shaped metal body, which has been appropriately pretreated, is subjected to heavy polishing treatment while passing through the ultra-high pressure water jet device, but in general, it is subjected to hot rolling or subsequent steps. Since the thickness of the scale and the depth of surface flaws that occur in annealing and continuous casting of thin-walled slabs are at least about 5 to 10 μm, it is necessary to grind at least 10 μm to remove the scale and surface flaws. It is a 20μm to the Ken掃量 to do a blast
It The projection pressure for that is 1000 kgf / cm ² or more,
The particle size of the abrasive particles spouted with ultra high pressure water is # 40 ~ #
The range was 400 . That is, if the abrasive grain count is less than # 40, the load of grading in the post-process increases, and if it exceeds # 400, the polishing and cleaning efficiency deteriorates.
Ken by incorporating such abrasives to ultra high pressure water jet
Sweeping efficiency is extremely improved. The polishing treatment with ultra-high pressure water containing abrasive grains enables uniform descaling and flaw removal regardless of the shape and crown of the plate. On the other hand, in this polishing treatment , it is preferable to provide a plurality of nozzles in order to improve the nozzle life and efficiency, and to perform polishing in multiple stages, and in this case, in order to reduce the mechanical conditioning load,
The abrasive grain count may be sequentially increased and implemented. Heavy cleaning
When the surface roughness after Rmax exceeds 50 μm, a deep polishing sweep such as a scratch occurs, and in order to sufficiently remove this, the load of the surface conditioning in the subsequent step increases. Therefore, it is desirable to set Rmax ≦ 50 μm.

The strip-shaped metal body is passed through the leveler 8 to correct the shape of the plate for facilitating uniform grinding and polishing, and to correct the bending and burrs of the ears. Conditioning device 1
In step 2, the front and back surfaces of the strip-shaped metal body that has been subjected to heavy polishing are polished with the elastic grindstone roll 12a to smooth the material. The abrasive grain count of the elastic grindstone roll may be selected from the range of # 80 to # 600. That is, if it is less than # 80, the grain is too coarse as a smoothing agent, and even if it is cold-rolled later, the surface of the product has grinds and irregularities, and good surface quality cannot be obtained, and if it exceeds # 600, descaling and flaw removal are performed. This is because it is not possible to sufficiently smooth the polishing grain and remove the caught abrasive grains. Also,
As shown in Table 1-3, the table after surface conditioning
If the surface roughness Rmax exceeds 10 μm, it is cold rolled and further annealed.
Surface roughness due to grinding marks remains on the product after
The rank is C or less, and good surface quality cannot be obtained.
Therefore, the surface roughness before cold rolling should be Rmax ≦ 10 μm or less.
It was Desirably, that is, to obtain a product of gloss rank A or higher.
For this purpose, it is preferable to set Rmax ≦ 4 μm. With this conditioning, an elastic whetstone is applied to each surface of the metal strip.
It is preferable to arrange a plurality of stands having rolls in multiple stages, thereby reducing the roll load per pass,
It is possible to extend the roll life and further improve the grinding efficiency. At this time, it is preferable to set the abrasive grain count of the last stage roll of the elastic grindstone roll to # 240 or more, which facilitates forming the surface by cold rolling. Furthermore, the abrasive grain count of the final pass roll is # 400 after 3 passes or more.
By the above, the occurrence of burrs during grinding can be suppressed, so that good surface quality can be obtained even if direct cold rolling annealing is performed thereafter.

After that, the strip-shaped metal body is passed through a degreasing / cleaning device to remove oil, metal residue, scale powder, etc. adhering to the surface thereof, and then, if necessary, using only high-pressure water for condensation.
Ishoningu, and / or conditioning by Keisan'arai processing performed. Conditioning with only high-pressure water can be carried out to remove burrs formed during grinding, and a projection pressure for that is not sufficient if less than 100 kgf / cm ² and no effect is expected. . Lightly ablated on a strip of metal by light pickling,
Burrs formed during grinding are removed and smoothing and blurring are performed. The reason why the amount of fusing is within the range of 0.1 to 30 μm is that burrs cannot be sufficiently removed if the amount is less than 0.1 μm, and if it exceeds 30 μm, the surface pit-like irregularities in the etch pit become severe, and the cold rolling thereafter is performed. This is because it becomes difficult to build in. By such pickling treatment,
The sharp grinds are not rounded and the surface profile is improved, further improving the surface quality after cold rolling. For pickling, it is desirable to use sulfuric acid, nitric acid, and nitric hydrofluoric acid individually or in a plurality of treatments depending on the target material. You may perform electrolytic pickling using these liquids as needed. After pickling, the pickling solution is washed. Which of high-pressure water and light pickling is to be performed may be appropriately selected depending on the material of the material to be treated and the treatment conditions. After the above processing, it is wound on a tension reel.

As described above, in the present invention, the treatment is not performed in a separate line like the conventional heavy grinding, but is performed in-line, and the equipment is made compact along with the pickling treatment and the initial investment is reduced, and the cost is low. You can now perform descaling and flaw removal. Examples of the present invention will be described below.

[0018]

[Example] In accordance with a continuous process by the processing device array shown in FIG. 1, a strip-shaped metal body is subjected to heavy polishing treatment by spraying ultra-high pressure water and abrasive grains under the conditions shown in Table 1, conditioning using an elastic grindstone roll, and If necessary, conditioning with high-pressure water and conditioning with light pickling treatment were carried out, and the surface quality after treatment and the quality of the cold rolled annealed product were investigated and evaluated, and the results are also shown in Table 1. The conditions and methods for heat treatment and pretreatment before in-line grinding are also described. In this table, the amount of polishing and the amount of grinding were measured before and after the treatment, and the removed thickness was calculated from the specific gravity. The evaluation of descaling and flaw removal was performed as follows. ：: No scale residue and no surface flaw. Δ: No scale remains, but surface flaws remain. X: Scale and surface flaws remain. In addition, the surface quality of cold-rolled and annealed products depends on the degree of gloss.
And 5 ranks A to D were evaluated, and B rank or higher was regarded as the first grade. The conditions for cold rolling annealing were normal conditions. In addition, cold
The cold rolling rate in rolling was 50% or more. As is clear from this table, the evaluation results of the strip-shaped metal body according to the method of the present invention are all good, and no scale residue or surface flaws are observed,
Good surface properties are obtained for the product after cold rolling annealing, and the average life of the elastic grindstone roll is improved by making the roll into multiple passes.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

As is apparent from the above, in the present invention, when removing the surface scale and surface flaws, the in-line grinding and conditioning treatments are performed in-line, and the pickling treatment is continuously performed to treat the strip-shaped metal body. To improve the surface quality of the strip-shaped metal body and to simplify the descaling and surface flaw removal process and pickling process to further improve efficiency, and reduce the production cost and pollution control by simplifying the acid and waste liquid treatment. Cost can be reduced and working environment can be improved. In addition, it has become possible to omit flaw removal on another line by continuous processing.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an embodiment for carrying out the present invention.

[Explanation of symbols]

 1 Payoff reel 2 Band metal 3 Welding machine 4 Trimmer 5 Edge grinder 6 Heating furnace 7 Cooling zone 8 Leveler 9 Ultra high pressure water injection device (front side) 9a Injection nozzle 10 Ultra high pressure water injection device (back side) 10a Injection nozzle 11 Bridle roll 12 Conditioning (In-line Grinding) Device 12a Elastic Whetstone Roll 12b Pressing Roll 13 Degreasing Cleaning Device 13a Brush Roll 13b Pressing Roll 13c Spray 14 Light Pickling Device 15 Cleaning Device 15a Brush Roll 15b Pressing Roll 15c Spray 16 Tension Reel

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masafumi Takai 3434 Shimada, Hikari City, Yamaguchi Prefecture, Nippon Steel Works, Ltd., Hikari Steel Works (72) Toshihiko Uchida 3434 Shimada, Hikari City, Yamaguchi Prefecture, Japan Inside the Hikari Steel Works, Ltd. (72) Inventor Kazumi Daitoku 1-1 Tobahata-cho, Tobata-ku, Kitakyushu City, Kitakyushu, Japan Inside the Yahata Works (72), Nippon Steel Co., Ltd. Hiroyuki Matsumura Central, Kobe City, Hyogo Prefecture 3-1, 1-1 Higashikawasaki-cho, Ward Kawasaki Heavy Industries, Ltd. inside the Kobe factory (72) Inventor Kyoji Tsujita 3-1-1, Higashikawasaki-cho, Chuo-ku, Kobe, Hyogo Prefecture Kawasaki Heavy Industries, Ltd. Inside the Kobe factory (72) Inventor Yoshikazu Ikemoto 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Kobe factory (72) Inventor Yoshio Arai Hamamatsu-cho, Minato-ku, Tokyo 4-1-1 Kawasaki Heavy Industries, Ltd. Tokyo Head Office (56) References JP 59-24512 (JP, A) JP 49-45808 (JP, A) JP 47-42335 (JP, A) ) Actual development Sho 62-101621 (JP, U)

Claims (9)

[Claims] 1. In the treatment of a strip-shaped metal body, the surface layer portion of the strip-shaped metal body having a scale on its surface has a size of # 40 to #.
Projection pressure including abrasive grains in the range of 400 is 1000 kgf / cm ²
With the above ultra-high pressure water, the polishing amount should be 20 μm or more.
After polishing, the roughness of the finished surface at that time is set to Rmax ≤ 50 μm
And, by conditioning the blast surface by subsequent mechanical means, Rmax ≦ 10 [mu] a surface roughness before cold rolling
and m, followed characterized by cold rolling surface texture
An excellent method for treating a strip-shaped metal body. 2. In the treatment of a strip-shaped metal body, the surface layer portion of the strip-shaped metal body having a scale on its surface has a size of # 40 to #.
Projection pressure including abrasive grains in the range of 400 is 1000 kgf / cm ²
With the above ultra-high pressure water, the polishing amount should be 20 μm or more.
After polishing, the roughness of the finished surface at that time is set to Rmax ≤ 50 μm
And, Conde the blast surface by subsequent mechanical means
After conditioning , further conditioning and cold rolling
A method for treating a strip-shaped metal body having excellent surface properties, characterized in that the surface roughness before is set to Rmax ≦ 10 μm, and then cold rolling is performed . 3. A mechanical conditioning is performed by disposing a stand, which is a pair of a pressing roll facing the elastic grindstone roll, for mechanical conditioning.
A method for treating a metal strip having excellent surface properties . 4. The method for treating a strip-shaped metal body having an excellent surface property according to claim 2, wherein the conditioning performed after the conditioning by mechanical means is polishing with high-pressure water. 5. The method for treating a strip-shaped metal body having excellent surface properties according to claim 2 or 4, wherein the projection pressure in conditioning with high-pressure water is 100 kgf / cm ² or more. 6. The surface texture according to claim 2, wherein the conditioning performed after the conditioning by mechanical means is a fusing treatment by light pickling.
Excellent method for treating strip metal. 7. The method of claim 2 certain <br/> surgeons excellent treatment method of the strip metal body surface properties of 6, wherein the scarfing amount in Keisan'arai conditioning is 0.1μm or more. 8. The strip-shaped metal having excellent surface properties according to claim 2, wherein the conditioning performed after the conditioning by mechanical means is a polishing treatment with high-pressure water, and then a fusing treatment with a light pickling. How to treat the body. 9. The surface layer portion of the metal band having a scale on the surface projection pressure containing abrasive grains 1000 kgf / cm ² or more super
The treatment of the strip-shaped metal body having excellent surface properties according to claim 1 or 2, wherein the treatment for performing the polishing with the high-pressure water so that the polishing amount is 20 µm or more is performed in a plurality of stages. Method.