JPH05269517A - Line of devices for removing surface defects on stainless steel strip - Google Patents

Abstract

PURPOSE:To efficiently remove scales bitten into the base metal and to obtain an excellent surface property by arranging a vacuum processing room, a surface conditioning device and a light pickling device in sequence. CONSTITUTION:A stainless steel strip 2 is introduced into the vacuum processing room 5 through a vacuum controlling room 4 and irradiated with discharge arc through a circuit constitution of electrodes 7 and conductor rolls 8. The discharge arc in the vacuum starts from a place of scale, the scale is removed by lightning evaporation and when the base metal surface appears, the arc does not spark on the metal surface, moves to a scale part small in work function and begins discharging. The steel strip 2 arc-processed in such a way is introduced into the conditioning device 12, both its faces are ground by an elastic grinding roll 14 having an axis in the direction of the steel strip width to flatten the arc spot shaped surfaces generated by arc processing. Then, a nick leveler is arranged to remove a barrier surface having small nicks and cleaning is performed by a light pickling device 16 to remove a surface case.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus train for removing surface scale and surface flaws produced in a hot rolling process or a thin cast continuous casting process in a stainless steel strip.

[0002]

2. Description of the Related Art In the manufacturing process of strip-shaped metal bodies, oxide scales and surface flaws are generated on the surface of strip-shaped metal bodies due to heating of the slab and subsequent hot rolling or continuous casting of thin-walled slabs. And a process for finishing the surface is required. Conventionally, as a metal descaling method, chemical treatment with an acid or 0.2 to
Known are a shot blast for blasting a 0.6 mm diameter steel ball for surface cleaning, a mechanical grinding method for polishing with a brush or a belt or a roll-shaped grindstone, and a grinding treatment method combining these. Each of these methods has advantages and disadvantages in terms of equipment or surface conditions.

On the other hand, Japanese Unexamined Patent Publication No. 57-56109 discloses a hot strip descaling method in which an electron beam, a laser, and a discharge arc are irradiated to melt and evaporate the scale. In general, the scale is mainly composed of an oxide layer of Fe, which bites into the surface of the ground iron and shields the ground iron from the environment. However, after the scale is removed by, for example, the discharge arc presented in the above publication, the scale is removed. An arc pot-like unevenness is formed on the base metal surface, which may cause uneven gloss on the product surface.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems, and in removing surface scale and surface flaws of a stainless steel strip, descale and flaw removal by discharge arc are performed. An object of the present invention is to provide a surface flaw removal device row for a stainless steel strip capable of efficiently removing the base bite scale and obtaining excellent surface properties by combining the subsequent surface adjusting means.

[0005]

In order to achieve this object, the present invention relates to a stainless steel strip processing line,
A vacuum processing chamber in which a multi-divided electrode and a conductor roll are placed in opposition in the width direction of the steel strip with a pass line interposed therebetween, and a surface conditioning device having one or more stages of elastic grindstone rolls whose axial direction is the width direction of the steel strip. The gist is a surface flaw removal device row of a stainless steel strip in which light pickling treatment devices with a scraping amount in the range of 1 to 30 μm are sequentially arranged.

[0006]

According to the present invention, a stainless steel strip is introduced into a vacuum chamber maintained at a vacuum of 1 to 10 ^-3 Torr, and a discharge arc generated between the strip and the electrode deeply meshes the steel strip surface layer and the surface layer. Maximum scale roughness (Rmax) is obtained by melting and evaporating the embedded scale to remove it, and then grinding the rough steel strip surface formed with an elastic whetstone roll using relatively fine abrasive grains.
To 10 μm or less, and then the above-mentioned light pickling is carried out to finish a stainless steel strip having an excellent smooth surface.

The present invention will be described in detail below with reference to the embodiments shown in the drawings. In FIG. 1, 1 is a payoff reel,
Reference numeral 2 is a stainless steel strip, 3 is a bling roll, 5 is a vacuum processing chamber, vacuum regulation chambers 4 and 6 are provided in front of and behind it, and electrodes 7 and conductor rolls 8 are alternately arranged, and a path of the steel strip 2 is provided. Opposite the line. The electrode 7 is shown in FIG.
As shown in FIG. 5, the electrodes 7a to 7n are divided into a plurality of parts, which are arranged in multiple stages. 9 is a vacuum arc controller connected to a computer 10, 11 is a bridle roll,
Reference numeral 12 denotes a surface conditioning device, in which at least one pair of elastic grindstone rolls 14 paired with the pressing roll 13 are installed on the front and back of the steel strip. Reference numeral 15 is an elastic grindstone roll controller connected to the surface conditioning device 12. 16 is a pickling tank, 17 is a pickling tank controller, 1
Reference numeral 8 is a cleaning tank, and 19 is a tension reel.

The present invention has the above-mentioned structure, and the stainless steel strip set on the pay-off reel is always 1 to 1 times.
It is introduced into the vacuum processing chamber 5 through the vacuum adjusting chamber 4 on the inlet side which is maintained at a vacuum of 0 ^-3 Torr, and the discharge arc is irradiated by the circuit configuration of the electrode 7 and the conductor roll 8. The discharge mode is given by the controller 9 based on an instruction from the computer 10 in which the current, the voltage, the strength of the magnetic field, the direction, the potential difference between the steel strip and the electrode, etc. are input in advance for each material. The discharge arc in a vacuum starts where the scale is, the scale is removed by electric shock evaporation, and when the base metal surface appears, the arc does not fly to the metal surface, it moves to the scale part with a small work function and discharge starts. . In a vacuum, many very small arc pots are generated at the cathode, which move rapidly and randomly, resulting in rapid scale removal.

The stainless steel strip subjected to the electric discharge arc treatment as described above is guided to a conditioning device, and the front and back thereof are ground by an elastic grindstone roll having a shaft in the width direction of the steel strip. The elastic grindstone roll referred to here is a roll-shaped grindstone with a certain degree of elasticity to make it easy to fit into the shape of the plate,
For example, laminating discs coated with abrasive grains and forming them into rolls (lamination type), laminating flap wheels into rolls (flap type), and nylon resin with abrasive grains integrally formed into rolls However, any of these can be adopted, but the laminated type is preferable.
The abrasive grain used for the elastic grindstone roll is not particularly limited, but # 120 to # 800 count is preferable, and when arranging a plurality of rolls on one side, the abrasive grain count on the final stage side from the preceding stage Should be large. If the treatment is performed in this manner, the arc pot-shaped surface generated by the vacuum arc treatment in the previous step can be ground and a smooth surface can be obtained.

Then, in order to remove the fine burrs and burrs on the ground surface and remove the hardened surface, the temperature (room temperature 100 ° C.) and concentration of the acid solution are controlled, and the surface is further removed. Abrasion amount is 1 to 30 μm
Pickling treatment is performed so that Abrasion amount is 1 μm
If it is less than 30 μm, the surface smoothing layer cannot be removed sufficiently, and if it exceeds 30 μm, the surface irregularities in the form of etch pits become severe, and it becomes difficult to form the surface quality by cold rolling after that. Such pickling treatment improves the surface profile and further improves the surface properties after cold rolling. The pickling is carried out by dipping the ground surface using an acid solution such as sulfuric acid, nitric acid and nitric hydrofluoric acid. The pickled stainless steel strip is washed with a pickling solution through a washing tank 18, dried, and then wound on a tension reel 19.

[0011]

As described above, in the present invention, the vacuum processing apparatus, the conditioning processing apparatus and the light pickling apparatus are in-line, and the surface scale and surface flaws of the stainless steel strip are efficiently removed by the discharge arc and the arc processing is performed. A stainless steel strip having excellent surface quality can be obtained by making the surface a smooth surface having a small roughness with an elastic grindstone and further performing simple pickling.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a main part of FIG.

[Explanation of symbols]

 1: Payoff reel 2: Stainless steel strip 3: Bring roll 4, 6: Vacuum adjustment chamber 5: Vacuum processing chamber 7: Electrode 8: Conductor roll 9: Vacuum arc controller, 10: Computer 11: Bridle roll 12: Surface Conditioning device 13: Presser roll 14: Elastic whetstone roll 15: Elastic whetstone roll controller 16: Pickling tank 17: Pickling tank controller 18: Washing tank 19: Tension reel

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yusuke Oikawa 3434 Shimada, Hikari City, Yamaguchi Prefecture Shin Nippon Steel Co., Ltd.

Claims (1)

[Claims] 1. In a stainless steel strip processing line,
A vacuum processing chamber in which a multi-divided electrode and a conductor roll are placed in opposition in the width direction of the steel strip with a pass line interposed therebetween, and a surface conditioning device having one or more stages of elastic grindstone rolls whose axial direction is the width direction of the steel strip. A row of surface flaw removing devices for a stainless steel strip, in which light pickling treatment devices each having a scraping amount in the range of 1 to 30 μm are sequentially arranged.