JPS6234617A - Descaling device for steel slab - Google Patents

Abstract

PURPOSE:To remove scales easily by setting pinch rolls which roll on a steel slab, impress pressing force on the slab, and generate cracks in scales formed on the slab surface and brashes which remove the scales before heating the slab. CONSTITUTION:A heating furnace 16 to heat a steel slab 14 carried by carrier rollers 12 is installed in a steel slab carrier path 10 for a hot rolling process. A couple of pinch rolls 18 and 20 rolling on the slab 14 and holding the slab 14 are set at the upstream side of the furnace 16. The rolls 18 and 20 impress a pressing force of about >=3 ton on the slab 14 and generate cracks in scales formed on the surface of the slab 14. Then, a couple of upper and lower brush rolls 22 and 24 installed between the pinch rolls 18, 20 and the furnace 16 remove cracked scales.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application] This invention relates to an apparatus for removing scale from steel materials in a hot rolling process in which steel materials are heated and rolled.

[Prior Art] A steel slab manufactured by a continuous casting method is air-cooled to room temperature in order to correct steelmaking defects (such as blowing). During this cooling, scale is formed on the surface of the steel piece, but this scale is removed by a cold scarf and a handscarf after the steel piece is cooled. Then, the steel piece from which the scale has been removed is placed on a conveyance line in a hot rolling process, conveyed to a heating furnace, heated there, and then rolled by rolling rolls.

However, in recent years, the number of tonal defects in steel billets has decreased, and due to energy conservation policies, continuously cast steel billets are transported to a hot rolling process without being cooled to room temperature and are continuously rolled. In this case, the continuously cast steel billets are stacked in three or four tiers on a trolley for heat retention and transported to the transport line for the hot rolling process, but during transport, they are cooled by air. The surface temperature of the steel piece will drop to around 300 to 800°C. Although a thick scale (approximately one gate thick) is formed on the surface of the steel billet due to oxidation accompanied by such a decrease in surface temperature, the steel billet is transported as it is to the heating furnace for the rolling process.

[Problem to be Solved by the Invention 1] However, when a steel billet is carried into a heating furnace with scale formed on its surface, as shown in FIG. Due to this action, the temperature of the area where the scale has adhered is not sufficiently raised, resulting in uneven temperature distribution on the surface of the steel piece. If the temperature of the steel piece is not raised sufficiently in this way, material abnormalities will occur because the solid solution of aluminum and nitrogen in the steel piece in that part will not be sufficient, and furthermore, the finishing temperature will fall below the Ari transformation wetness. A problem arises in that coarse grains are generated on the surface. Conventionally, in order to deal with this problem, the temperature inside the heating furnace is increased to increase the temperature including the scaled parts, but this method has the disadvantage of increasing fuel costs.

[Means for Solving the Problems] This invention has been made in view of the above circumstances, and it is possible to easily remove scale on the surface of the steel material before carrying the steel material into a heating furnace. The purpose of the present invention is to provide a scale removal device for steel materials.

In the hot rolling process in which the steel material is heated and rolled in a heating furnace, the steel material descaling device according to the present invention is installed in a conveyor line that conveys the steel material before the heating furnace so that the steel material rolls on the steel material and adheres to the surface of the steel material. A pair of pinch rolls are provided to form cracks in the scale, and a brush roll is provided between the pinch rolls and the heating furnace to remove scale from the steel material. It is characterized by removing scale by scraping.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 9 of the accompanying drawings.

As shown in FIG. 1, a heating furnace 16 is provided in a conveyance line 10 for steel billets (steel materials) in a hot rolling process to heat billets 14 conveyed by conveyance rollers 12. . In the conveyance line 10, a pair of pinch rolls 18 and 20 are provided on the insertion side of the heating furnace 16 to roll the steel piece and pinch it. Preferably, each pinch roll 18.20 is O-let or shot so as to form irregularities on its circumferential surface, and the pinch roll 18.20 has a diameter of about 3 or more per rope. In the embodiment, a pressing force of approximately 3 t is set to apply.

An upper brush roll 22 and a lower brush roll 24 are arranged between the pinch roll 18.2o and the heating furnace 16 for removing scale in which cracks are formed.

The upper and lower brush rolls 22 and 24 are as shown in FIG.
A stainless steel brush 26 is attached to the upper roll 2 on its peripheral surface.
8. Embedded in the lower roll 30. The lower roll 30 is supported at both ends in fixed bearings 32,34. Both ends of the upper brush roll 2 are supported by bearings 36 and 38 that are vertically movable. The upper ends of these bearings are pressed by air cylinders 40, 42, respectively, and the pressure of the brush against the steel piece can be set to a predetermined pressure when removing scale.

Next, the configuration of the brush 26 will be explained. brush 26
As shown in Fig. 3, a plurality of thin stainless steel wires 44 (Φ0.1 to 0.4 #lI) and a slightly thicker steel wire 46 (Φ0.3 to 0.6 mm) are mixed. The wires are then wrapped around each other and twisted together to form a stranded wire 48. In this case, the thick steel wire 46 is mixed at a ratio of 60 to 70% and the thin steel wire 44 is mixed at a ratio of 30 to 40%. The stranded wire 48 is bent into a wave shape as shown at the right end in FIG. 3 to form waveform 1! Formed at l150. As shown in FIG. 4, steel 152 is spirally wound around the outer periphery of the corrugated stranded wire 50. As shown in FIG. The wavy stranded wire 50 formed in this manner is used as a unit material of the brush 26. Furthermore, each unit material (wavy twisted wire 50
), the steel wire is untwisted as shown in FIG. This untwisting forms a cluster of steel wires with wavy patterns of small and large brush diameters. In addition, steel wire 4
4 or 46 has a round cross-sectional shape as shown in FIG. 6, but steel wires having a hexagonal cross-section at tAB may be mixed as shown in FIG. Stranded wire 5 like this
0 is made of multiple steel wires with two or more different diameters, the thick steel wire compensates for the wear of the brush, which is the weak point of thin steel wire, and the thin steel wire compensates for the occurrence of scratch patterns, which is the weak point of thick rlI wire. You get the benefits of making up for it with your desk. Furthermore, since the stranded wire 50 has a wave shape, the combined effect of the wave shape and the wave shape due to the untwisting tendency works, so the brush is difficult to bend against the rolling blade on the surface of the red-hot steel billet, and has a rich restoring force and provides good descaling. As well as achieving
It can extend the life of the brush.

Next, the operation of the apparatus for removing scale from a steel billet constructed as described above will be explained. The surface of the steel piece 14 conveyed to the conveyance line is pressed with a pressing force of about 3 tons by or as the pinch rolls 18 and 20 roll.

Since the pinch roll 18.20 has unevenness formed on its peripheral surface, it effectively and easily cracks the scale formed on the surface of the steel piece, and the adhesion between the steel piece and the scale is peeled off. .

The scale on the surface of the steel plate where the cracks have been formed is then removed by brush rolls 22,24.

The billet is then conveyed between brush rolls 22,24. The brush rolls 22, 24 are rotated at a weekly speed of about 50 m/min relative to the steel billet, and are rotated in a direction opposite to the conveyance direction of the steel billet. These brush rolls 22, 24 remove scale from the steel piece.

In this case, since cracks have been formed in the scale in advance by pinch rolls, the scale can be easily peeled off from the steel piece and swept away. The steel piece from which the scale has been removed is conveyed to a heating furnace 16, where it is heated sufficiently and approximately uniformly and then rolled. Figure 8 shows the temperature distribution after heating, rough rolling and finish rolling of the surface of the steel strip from which the scale has been peeled off in this example, and the temperature distribution on the surface of the steel strip when the same treatment has been performed without peeling off the scale. As shown in FIG. 9, as is clear from these two figures, according to this example, since the scale on the surface of the steel piece is sufficiently removed, a substantially uniform temperature distribution can be obtained. I can do it.

This invention is not limited to the one embodiment described above, and can be modified in various ways without departing from the gist of the invention.

For example, the stranded wires of the brush are not limited to using uAm wires having different wire diameters, but the same effect can be obtained by using steel wires having approximately the same wire diameter.

The direction of rotation of the brush roll is not limited to the opposite direction to the conveyance direction of the steel billet, but the same effect can be obtained even if it is rotated in the same direction as the conveyance direction of the steel billet as long as it rotates relative to the steel billet. be able to.

Moreover, the brush rolls are not limited to being provided on both the upper and lower sides of the steel piece, but may be provided only on one side. In this case, the scale on only one side is removed, but it is more advantageous to provide a brush roll only on the upper side because the scale on the lower side falls off due to the vibration during conveyance by the roll 12, thereby removing the scale.

[Effects of the Invention] According to the present invention, a pinch roll that rolls on a steel piece before heating the steel piece and applies a pressing force to cause cracks in scale formed on the surface of the steel piece; Since it is equipped with a brush for removing this scale, scale stuck to the surface of the steel piece can be easily removed. Furthermore, even if the energy of the heating furnace is reduced, the steel material can be heated uniformly.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a hot rolling line equipped with a steel billet scale removal device according to an embodiment of the invention, FIG. 2 is a schematic sectional view of the brush roll shown in FIG. 1, and FIG. A perspective view of the stranded wire showing the configuration, FIG. 4 is I! perspective view of the line,
Figure 5 is l! 6 is a sectional view of the stranded wire, FIG. 7 is a sectional view of the stranded wire 48 according to a modification of the embodiment shown in FIG. FIG. 9 is a graph showing the temperature distribution at the finished rolling outlet when a copper strip after scale removal is heated by heating, and FIG. 9 is a graph showing the temperature distribution at the finished rolling outlet of the steel strip when scale remains. 16...Heating furnace, 18.20...Pinch roll, 2
2.24... Brush roll. Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 4rg Figure 6 Figure 7

Claims (1)

[Claims] In the hot rolling process where steel is heated and rolled in a heating furnace,
In front of the heating furnace, the conveyance line for conveying the steel material is provided with a pair of pinch rolls that roll on the steel material and form cracks in the scale attached to the surface of the steel material, and a pair of pinch rolls are provided between the pinch rolls and the heating furnace. What is claimed is: 1. A steel material scale removal device, comprising: a brush roll for removing scale from a steel material; the apparatus is characterized in that the scale is removed by scraping off the scale with a brush after cracking the scale;