JP3140594B2 - Mechanical descaling method and scale crushing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical descaling method for removing scale from the surface of a slab or bloom cut to a predetermined length after continuous casting, and to a scale crushing apparatus therefor.

[0002]

2. Description of the Related Art A slab obtained by a continuous casting facility is cut into a predetermined length and then hot-rolled. When a slab is to be hot-rolled, it is heated in a heating furnace, then subjected to a rough rolling mill, and then to a finish rolling mill to obtain a product having desired specifications. By the way, in a heating furnace, oxide scale is generated on the slab surface, and if this is not removed before rolling, the scale is pushed in by rolling and remains as a surface flaw. High-pressure water with a pressure of ² was sprayed on the slab surface, and the scale was removed by blowing off the scale.

However, in such a method of removing scale by jetting high-pressure water, it has not been possible to completely remove the scale. In particular, in a slab containing many alloying elements such as silicon (Si), nickel (Ni), and copper (Cu), the generated scale has strong adhesion,
Descaling was almost impossible.

[0004] Therefore, it has been proposed to remove scale by mechanical means.
No. 381, U.S. Pat. No. 1984762, JP-A-61-2
No. 36412 and the like. The technology described in British Patent No. 736381 discloses that the entire device rides on the upper surface of a hitting object (workpiece), and a lever-shaped tool is rotated while self-propelling the device, and a piece-shaped striking provided at a tip end thereof. The scale is removed by pressing the head against the surface of the body to be hit and scraping off the scale. Further, in the technique described in US Pat. No. 1984762, a wheel having a disk shape and having a corrugated surface formed over the entire periphery of the periphery is multilayer-contacted to a rotating shaft, externally fitted and fixed, and the wheel group is rotated. The scale is removed by bringing the tip into contact with the surface to be processed and scraping the scale. Further, the technique described in Japanese Patent Application Laid-Open No. 61-236412 discloses a technique in which a plurality of hammers are mounted at a fixed interval in a circumferential direction of a disk-shaped support plate externally fitted on a shaft so as to be finely movable in a line in a radial direction, The scale is removed by contacting the tip with the surface of the slab.

[0005]

However, in the prior art described above, in the case of British Patent No. 736381, since the apparatus moves on the upper surface to remove scale,
In addition to being unable to remove the scale from the lower surface, the tip of the impacting body has a sharp shape, and when the slab is struck with heat, sharp dents remain on the surface of the work surface. But there is a problem that it remains without disappearing. UK Patent 19847
In the case of No. 62, a large impact force cannot be obtained due to its structure,
Sufficient scale crushing effect cannot be obtained.

Further, the structure described in Japanese Patent Application Laid-Open No. 61-236412 is effective for removing the curl at both ends of the slab, but when used for removing the scale of the entire slab, the shape of the impact body head is reduced. Is so sharp that dents after rolling cannot be eliminated. Further, since there is no means for holding down the upper surface of the slab during the impact, the vibration at the time of the impact increases, and the irregularity of the impact also increases, so that it cannot be put to practical use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a mechanical device capable of removing scales on both surfaces of a workpiece uniformly in the width direction without flaws on the surface. An object of the present invention is to provide a descaling method and a scale crushing device.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a mechanical descaling method for removing scale attached to a slab or bloom while transferring it from a heating furnace to a rolling mill. The envelope drawn by the tip of the striking body using a scale crushing device having a striking body attached in a staggered manner around the rotation axis so as to be rotatable in the circumferential direction is drawn with respect to the surface of the slab or bloom. The slab or bloom cooled in advance by the cooling means is set to overlap by 5 mm or more, enters the scale crushing device, and the tip of the slab or bloom reaches the predetermined position and the rotating slab or bloom is in the raised position. The striking body is moved to the overlap position and the slab or bloom is conveyed to break the scale. Conveying the slab or bloom after termination of Le crushed into the rolling mill direction, followed by removal of scales by jetting high-pressure water to the slab or bloom on the surface at the conveying process.

The above scale crushing device is divided into a plurality of pieces in a longitudinal direction on a peripheral surface of a main shaft installed horizontally in a slab width direction above and below the slab, and is rotatably arranged in a line. , A plurality of rows of striking bodies provided in a staggered state at a predetermined pitch in the circumferential direction, pressing rollers installed on the front and rear upper sides of the striking bodies, and a circumference of a tip end of the striking body that contacts the cast slab. The ridgeline is rounded in the range of 5 to 20R, and the envelope drawn by the impacting body with the rotation of the main shaft overlaps the slab surface by 5 mm or more and the slab impact pitch in the impact direction is 25 mm or less. It is possible to adopt a configuration provided with setting means.

[0010]

According to the above means, the slab or bloom that has been cooled after being heated is scaled by the effect of the overlap due to the sliding contact of the striking body having a predetermined overlap with the surface thereof. The crushed scale is completely crushed, and the scale is crushed sequentially from the front end to the tail end as the slab or bloom is conveyed, and the crushed scale is removed from the surface of the slab or bloom by jetting high-pressure water. Therefore, the scale on both surfaces of the workpiece can be uniformly removed in the width direction without flaws on the surface.

According to the above-mentioned other means, the striking body which is divided into a plurality of pieces along the axial direction of the main shaft and arranged in a line, and a plurality of these pieces are provided in the circumferential direction, The lap, the circumferential ridge shape at the tip end, and the slab impact pitch are each set to a value at which the best scale crushing effect can be obtained with respect to the sliding contact accompanying the rotation of the main shaft. Therefore, the scale on both sides of the slab or bloom can be effectively crushed uniformly in the width direction with a simple configuration.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the outline of a scale crushing apparatus and rolling equipment for achieving the method of the present invention.

A heating furnace 2 is provided for heating the slab 1, and a nozzle 3 (cooling means) for cooling the upper and lower surfaces of the slab 1 is provided at a subsequent stage. This nozzle 3
A scale crushing device 4 for crushing and removing scale on the surface of the slab 1 is provided at a subsequent stage, and a high-pressure water injection device 5 for removing scale crushed by the scale crushing device 4 is provided at a subsequent stage of the scale crushing device 4. Is installed. A rolling mill 6 is sequentially installed downstream of the high-pressure water injection device 5.

In the above configuration, the slab 1 is
The oxide scale is generated on the surface of the slab 1 by heating. In this state, the slab 1 is transported between the nozzles 3 and the injected cooling water is supplied to the slab surface, whereby the oxide scale floats up from the surface. The lifted scale is completely scraped off by the next-stage scale crusher 4, and the scraped scale is washed away by the high-pressure water jetted from the high-pressure water jetting device 5, and the scale remains on the slab 1. I will not do it. Moreover, scales on both sides can be removed at the same time.

FIG. 2 is a side view showing the details of the scale crushing apparatus 4, and FIG. 3 is a front view thereof. A hammer is installed in a staggered manner so that the slab surface scale can be completely peeled off. The front view of the conventional scale crushing apparatus is arranged as shown in FIG. 4, and a portion where the slab surface scale peels (a position where the hammer hits) and a portion where the slab surface scale does not hit (the position where the hammer does not hit) occur. there were. In addition,
In the figure, reference numeral 8 denotes a conveying roller disposed at a predetermined interval below the slab 1 and used for conveying the slab 1;
Is a slab pressing roller disposed above the slab 1 before and after the scale crushing position to suppress vibration of the slab 1. In each case, illustration is omitted in FIG.

The rotating shaft 41 has a plurality (13 in this embodiment).
) Are externally fitted and fixed by some means. In each of the flanges 42, through holes are provided at equal intervals in the circumferential direction, and the striking body rotation shafts 43 are inserted between the through holes at the same position, respectively.
Both ends are fastened and fixed to flanges 42 provided on both sides by bolts 44. Further, a plurality of striking bodies 45 are supported on the striking body rotation shaft 43 in a staggered state on the surface of the striking body rotation shaft 43 in close contact. Each of the impacting bodies 45 can freely rotate in the circumferential direction of the rotary shaft 41, and in a stationary state where the impacting body 45 does not rotate, as shown in FIG. Then, as shown in FIG. 6 (front view) and FIG. 7 (side view), the tip of the impacting body 45 is rounded in the range of 5 to 20 R in the circumferential ridge line so as to suppress generation of flaws. I am careful. Further, as shown in FIG. 4, the striking bodies disposed on both sides of the intermediately disposed flange 42 have a front end projecting horizontally in order to fill a space corresponding to the flange width. A body 46 is used.

The impacting body 45 is pivotally supported on the impacting body rotating shaft 43 in a staggered state. By supporting in a staggered state,
The scale adhering to the slab surface can be removed uniformly in the width direction (FIG. 3).

In the conventional alignment state, a gap is formed between the impacting bodies 45, and the scale adhering to the slab surface cannot be uniformly removed in the width direction (FIG. 4). In other words, the position where the hammer hits the slab is determined in the aligned state, and the scale is removed unevenly in the width direction, thereby causing an obstacle to the product.

In the scale crushing mechanism having the above-described structure, a scale crushing mechanism 4a and a scale crushing mechanism 4b having the same structure are symmetrically disposed above and below the slab 1 as shown in FIG. A crushing device 4 is formed.

Here, the operation of the scale crushing apparatus 4 will be described. A sensor (not shown) detects the tip of the slab 1 and both the scale crushing mechanisms 4a and 4b move to the slab 1 side, and the rotating shaft 41 rotates at 400 rpm, for example. And the striking body 45 rotates accordingly. At this time, the tip end face of the impacting body 45 is overlapped with the overlap amount L from the surface of the slab 1.
(In fact, since the impacting body 45 is rotatably mounted, it does not bite into the slab 1, but it is considered here virtually) so that the shaft center of the rotating shaft 41 is inserted. Set the position. In this embodiment, the overlap amount L is set to 5 mm or more.

At this time, the impacting body 45 is located at the front end of the slab 1. When the slab 1 is transported in the forward direction from this state, the scales of the upper and lower surfaces of the slab 1 are successively increased from the front end to the rear end. Crushed by the impacting body 45 and processed to a state where it can be easily removed.

By the way, there are various conditions for improving the descalability, and specifically, the shape of the head of the impacting body 45,
The value of the overlap amount L, the slab impact pitch, and the like.
The details will be described below. The rolling conditions here were such that the thickness after rolling was 100 mm for a slab thickness of 240 mm.
mm.

FIG. 8 shows the relationship between the shape of the impacting body head and the scale removability and flaws, FIG. 9 shows the relationship between the overlap amount L and the scale removability, and FIG. It shows a sexual relationship. As is clear from FIG. 8, the R dimension of the ridge line on the four circumferences of the impacting body head is 2 mm to 2 mm.
When the quality of skew removability was judged while changing the thickness up to 4 mm, good results were obtained up to 22 mm, but when it was more than 22 mm, flaws on the flaw part scale and remaining flaws were generated. In addition, when the presence or absence of flaws remaining after rolling was checked, it was found that 2-3 mm
Then, a dent occurred. From this fact, in order to realize descalability and no flaws remaining after rolling, the R dimension must be 4
It can be seen that the distance should be set to a range from 0.2 mm to 22 mm.

Further, as shown in FIG.
Was increased in increments of 1 mm from 1 mm to 15 mm, and the quality of the scale removability was determined. Good results were obtained from 4 mm or more. As is clear from this, if the overlap is set to the zero state as in the known example, the scale removal becomes insufficient.

Further, as shown in FIG.
(Where P = V / NM and V is the slab transport speed (mm /
min), N is the number of rotations (rpm) of the striking rotating body, and M is the number of rows of striking bodies (six rows), which was increased from 5 mm to 35 mm in 2 to 5 mm steps to determine the quality of the scale removability. As a result, good scale removability was obtained over 5 to 27 mm, and when 29 mm or more, scale residue occurred between the dents.

From the above, comprehensive judgment is made with a margin,
It can be seen that the overlap amount L should be set to 5 mm or more, the slab impact pitch P should be set to 25 mm or less, and the R dimension should be set to about 5 mm to 20 mm.

[0028]

Since the present invention is constituted as described above, the following effects can be obtained.

In the mechanical descaling method according to the first aspect, the scale attached to the slab or the bloom is removed while being transported from the heating furnace to the rolling mill. Using a scale crushing device having impacting bodies attached at regular intervals around the rotation axis so that the envelope drawn by the tip of the impacting body overlaps the surface of the slab or bloom by 5 mm or more. The slab or bloom, which has been set in advance and cooled by the cooling means, enters the scale crushing device, and when the tip reaches a predetermined position, the rotating striking body that has been in the raised position is moved to the overlap position. And the slab or bloom is transported to break the scale. After the end of crushing, the slab or bloom is conveyed in the direction of the rolling mill, and in the conveying process, high-pressure water is sprayed on the surface of the slab or bloom to remove scale, so that the surface is scratched. In addition, scale on both surfaces of the workpiece can be removed.

[0030] In the scale crushing apparatus of claim 2,
The scale crushing device is divided into a plurality of pieces in a longitudinal direction on a peripheral surface of a main shaft installed horizontally in a slab width direction of upper and lower slabs, and is rotatably installed in a row and predetermined in a circumferential direction. A plurality of rows of striking bodies provided at a pitch, a pressing roller installed above and below the striking body, and a circumferential ridge line at the tip end of the striking body that contacts the cast piece in a range of 5 to 20R. The envelope drawn by the impacting body with the rotation of the front and rear spindles overlaps the slab surface by 5 mm or more and the setting means for setting the slab impact pitch in the impact direction to 25 mm or less is provided. With a simple configuration, the scale on both sides of the slab or bloom can be effectively crushed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of a scale crushing apparatus and rolling equipment for achieving the method of the present invention.

FIG. 2 is a side view showing details of the scale crushing apparatus.

FIG. 3 is a front view (aligned state) of a conventional scale crushing apparatus.

FIG. 4 is a front view (in a staggered state) showing the details of the scale crushing apparatus.

FIG. 5 is a side view showing a stationary state of the scale crushing mechanism.

FIG. 6 is a front view showing details of a tip end portion of the hitting body.

FIG. 7 is a side view showing details of a tip end portion of the hitting body.

FIG. 8 is an explanatory diagram showing the relationship between the shape R of the impacting body head, the scale removability, and the dent in the present invention.

FIG. 9 is an explanatory diagram showing a relationship between an overlap amount L and scale removability in the present invention.

FIG. 10 is an explanatory diagram showing a relationship between a slab impact pitch P and scale removability in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slab 2 Heating furnace 3 Nozzle 4a, 4b Scale crushing mechanism 5 High-pressure water injection device 6 Rough rolling mill 7 Finishing rolling mill 41 Rotary shaft 42 Flange 43 Hitting object rotating shaft 44 Bolt 45 Hitting object 46 Hitting object

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-84510 (JP, A) JP-A-4-159068 (JP, A) JP-A-60-27413 (JP, A) JP-A-61-1984 236412 (JP, A) JP-A-1-178311 (JP, A) Japanese Utility Model Application Laid-Open No. 52-42414 (JP, U) Japanese Utility Model Application Publication No. Sho 62-6910 (JP, U) US Patent 1984762 (US, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21B 45/06 B21B 45/08 B23P 9/04

Claims (2)

(57) [Claims] 1. A mechanical descaling method for removing scale adhering to a slab or a bloom while being transported from a heating furnace to a rolling mill. Using a scale crusher having a striking body that uniformly strikes the entire slab surface, and is preset so that the envelope drawn by the tip of the striking body overlaps the surface of the slab or bloom by 5 mm or more. Then, the slab or bloom cooled by the cooling means enters the scale crushing device, and when the tip reaches a predetermined position, moves the rotating impacting body that was in the ascending position to the overlap position. And the slab or bloom is conveyed to crush the scale. A mechanical descaling method comprising: transporting bloom or bloom toward the rolling mill; and injecting high-pressure water onto the surface of the slab or bloom during the transport process to remove scale. 2. The scale crusher according to claim 1,
It is divided into a plurality of parts in the axial direction on the peripheral surface of the main shaft installed horizontally in the slab width direction above and below the slab and installed in a row so as to be rotatable, and these are staggered in the circumferential direction at a predetermined pitch. Provided,
A plurality of rows of striking bodies that uniformly descaling the entire slab, pressing rollers installed on the front and rear upper sides of the striking bodies, and a circumferential ridge line at the tip end of the striking body that contacts the cast slab is 5 to In the range of 20R, the envelope drawn by the impacting body with the rotation of the spindle is 5 mm from the slab surface.
A scale crushing apparatus comprising: setting means for overlapping the slab in the hitting direction so as to make the slab hitting pitch 25 mm or less.