KR20020016013A - Apparatus for covering casting roll - Google Patents

Abstract

PURPOSE: An apparatus for covering the surface of casting rolls in a twin roll strip caster is provided which not only efficiently cuts off contamination of the casting rolls due to fume inside a cover of molten surface but also prevents ceramic abrasion powder generated by friction between edge dams and end faces of the casting rolls from being stuck onto the casting rolls. CONSTITUTION: The apparatus for covering the surface of casting rolls in a twin roll strip caster comprises a rigid first cover means(100) the end part of which is not contacted with the surface of molten metal(50) so that the first cover means(100) is not closely adhered onto the surface of the casting rolls(3) of an environmental layer at the lower side of a molten surface cover, thereby preventing fume(40) and powder of edge dams from being stuck onto the casting rolls(3); a soft second cover means which is installed so that the lower end part of the second cover means is contacted with the surface of molten metal(50); and a third cover means in which the first cover means(100) and the second cover means are integrally associated with each other so that the third cover means is covered on the casting rolls(3).

Description

Casting roll surface covering device of twin roll sheet casting machine {APPARATUS FOR COVERING CASTING ROLL}

The present invention relates to a twin-roll type sheet casting machine for casting directly into a thin plate while cooling and solidifying the molten steel injected into a pair of the same size water-cooled, more specifically, the contamination in the water surface cover that is covered on the molten steel pool of the casting roll during sheet casting A pair to effectively prevent contamination of the casting roll by the gas (FUME) and to prevent the ceramic wear powder generated from the friction between the edge dams on both sides of the molten steel pool and the casting roll end face from adhering to the casting roll. The present invention relates to a casting roll surface covering apparatus of a roll type sheet casting machine.

In general, in the casting method of thin plate, the slab is manufactured by continuous casting method through the tundish of molten steel, the continuous casting method of manufacturing it into thin plate through rolling and finishing operations, and the molten steel is directly added to the rotating twin roll. There is a twin-roll type sheet casting method for directly manufacturing a sheet without rolling and finishing the slab through the latter, the latter can be manufactured directly without going through a number of processes of the continuous casting method, a considerable cost reduction and process in terms of cost Many studies have been conducted on such a twin roll sheet casting method.

Such a twin roll sheet caster is schematically shown in FIG.

That is, as shown in Figure 1, between the two casting rolls (3) rotating at a constant speed molten steel is supplied through the immersion furnace (2) installed to the lower side of the tundish (1), the molten steel storage container is cast roll (3) and the molten pool 5 is formed at the edge dams 4 on both sides thereof, the supplied molten steel is in contact with the casting roll 3 to be water-cooled to form the solidification shell 6, The casting is to cast the cast steel 20 at the roll closest contact.

Meanwhile, between the molten metal pool 5 and the tundish 1 between the casting rolls 3, a molten metal surface cover 7 which prevents oxygen from contacting with the surface of the molten metal pool 5 and is oxidized. ) Is installed to allow the nozzle 2 to pass through, and the outside is scattered to prevent the air from contacting the casting roll 3 and the bath surface 50 toward the casting roll 3 and the bath surface 50 in order to prevent oxidation. Supply ports 8 and 9 for supplying the chemical gas 30 are respectively provided.

Therefore, the supplied non-oxidizing gas 30 blocks oxygen from contacting the casting roll 3 and the hot water surface 50, thereby suppressing the oxidization of the molten metal as much as possible.

At this time, even if the atmosphere is formed of the non-oxidizing gas 30 on the hot water surface 50, if the component of the molten metal is steel, if there is a volatile component such as manganese, zinc, lead, etc., it is discharged as a gas from the molten metal, As a result, the vapor of the metal volatile component is mixed with the pure non-oxidizing atmosphere gas 30 to form a contaminant gas (FUME) 40.

Therefore, when the contaminant gas 40 contacts the surface of the casting roll 3, it is condensed and adsorbed on the surface of the casting roll 3, thereby hindering the heat transfer of the casting roll 3 of molten steel, making it difficult to uniformly solidify the cast steel. Therefore, it should be blocked.

On the other hand, Korean Patent 1999-56691 discloses a configuration to block the casting roll contact of such a contaminated gas 40, which is the reverse of the casting roll 3 in the discharge direction of the contaminated gas 40, that is, As shown in FIG. 1, the outlet 10 through which the polluted gas 40 is discharged is formed adjacent to the nozzle 2 of the bottom cover 7 to discharge the polluted gas 40 to the outside of the bottom cover 7. However, it is impossible to completely prevent the contaminated gas 40 from contacting the casting roll 3 completely.

In addition, the other contaminating the surface of the casting roll 3, apart from the contaminated gas, is caused by the friction between the edge dams 4 which are installed to form the molten pool 5 on both sides of the casting roll 3. Edge dam 4 is powdered.

In other words, the edge of the casting roll 3, the edge dam 4 is in contact with friction, that is, the end face is formed of a bronze nitride (BORON NITRIDE) -based ceramic, etc., the edge dam during the rotation of the casting roll (3) While a considerable amount of edge dam (4) powder is generated while rubbing with (4), most of them fly off when the pollutant gas 40 is discharged, but most of the dam dust is generated at the edge of the casting roll 3. As a result, it is attached to the surface of the casting roll 3 to be in contact with the hot water surface (50).

Eventually, the heat transfer of the molten metal 5 is interrupted by the edge dam powder as described above, so that the edge of the cast steel 20 has a relatively lower solidification speed than the center portion, resulting in unsolidification of the cast steel. Edge bulging with unsolidified edges (EDGE BULGING) is the cause, and such edge bulging parts need to be removed after casting. It is.

The present invention has been made in order to improve the various problems as described above, the object is that the contaminated gas mixed with the non-oxidizing gas supplied in the water surface cover and the volatile metal component evaporated from the water surface solidified adhered to the surface of the casting roll The present invention provides a casting roll surface covering device of a twin roll sheet casting machine to prevent the thickness variation of the solidification shell in advance by preventing heat transfer of the casting roll.

Another object of the present invention is to provide a double roll sheet caster to prevent edge dam powder caused by friction between the casting roll and the edge dam from adhering to the surface of the casting roll or contacting the melt to generate edge bulging due to poor solidification. The present invention provides a casting roll surface covering device.

1 is a schematic diagram showing a typical twin roll sheet casting machine

Figure 2 is a schematic view showing a first embodiment of the casting roll surface cover device of the twin-roll sheet caster according to the present invention

Figure 3 is a schematic view showing a second embodiment of the casting roll surface cover device of the present invention of a twin roll sheet caster

Figure 4 is a schematic view showing a third embodiment of the cast roll surface cover device of the present invention twin roll type sheet casting machine

Explanation of symbols on the main parts of the drawings

1 .... Tundish 2 .... Nojul

3 .... Casting Roll 4 .... Edge Dam

5 .... molten pool 6 .... solidified shell

7 .... Floor cover 8 .... Non-oxidizing gas supply port on roll side

9 .... Non-oxidizing gas supply side on the water surface 10 .... FUME outlet

11 .... Airtight curtains 20 .... Cast

30 .... Emission pollutant gas on the casting roll 40 .... Emission pollutant gas on the nozzle side

50 .... Tang noodles 100,100 ', 100 "' .... Cover means

104 .... Second cover means fixing member 108 .... First and third cover means fixing member

As a technical configuration for achieving the above object, the present invention, the molten steel supplied from the tundish is formed as a molten pool between the casting roll and the edge dam, the non-oxidizing gas in the bath surface cover provided between the cover In the twin-roll type sheet casting machine having an atmosphere layer supplied through, the hard roll is installed so that the lower end is not in contact with the molten surface to be in close contact with the casting roll surface of the atmosphere layer to prevent contaminant gas and edge dam powder from adhering to the casting roll By providing a casting roll surface covering device of a twin-roll sheet caster having a first cover means of.

In addition, as a second aspect of the present invention,

The molten steel supplied from the tundish is formed as a molten pool between the casting roll and the edge dam, and in the double-roll type sheet casting machine having an atmosphere layer in which a non-oxidizing gas is supplied through the cover in the hot water surface cover provided therebetween. Casting roll surface cover of a twin roll sheet caster having a second soft cover means which is attached to the molten surface so that the lower end is in contact with the molten surface so as to be in close contact with the cast roll surface of the layer to prevent contaminant gas and edge dam powder from adhering to the casting roll. By providing a device.

In addition, as a third aspect of the present invention,

The molten steel supplied from the tundish is formed as a molten pool between the casting roll and the edge dam, and in the double-roll type sheet casting machine having an atmosphere layer in which non-oxidizing gas is supplied through the cover in the bath surface cover provided therebetween. A third cover unit which is in close contact with the casting roll surface of the layer and is integrally coupled to the molten surface to prevent the contaminant gas and the edge dam powder from adhering to the casting roll, and the first cover means is integrally coupled to cover the casting roll. By providing a casting roll surface cover device of a twin-roll sheet caster having a cover means.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 to 4 are schematic views showing the first, second and third embodiments of the cast roll surface cover device of the twin roll sheet caster according to the present invention.

FIG. 2 shows a first embodiment of the casting roll surface covering device of the twin roll sheet casting machine of the present invention, wherein the molten steel supplied from the tundish 1 is roll 3 and the edge dam 4 as described above. ) Is formed as a molten pool (5), the metal gas volatilized in the molten metal 5 is mixed with a non-oxidizing gas 40 is discharged through the upper surface of the hot water cover (7) casting roll ( Attached to the surface of 3) is a device for blocking solidification.

That is, while the non-oxidizing gas 30 formed between the bottom surface 50 of the bottom surface 7 is supplied to the casting roll 3 surface of the atmosphere layer to which the non-oxidizing gas 30 is supplied, it is fixed to the bottom surface cover 7 and stretches closely. The first cover means 100 to be in close contact, that is, to provide a rigid thin plate cover 100 made of a metal thin plate, such as carbon steel or stainless steel.

At this time, the thin plate cover 100 should be installed by adjusting its length so that its lower end does not contact the surface of the molten metal 50. In reality, the surface of the thin plate 50 is changed so that the length is adjusted to have a certain amount of margin. This is because the thin plate cover 100 melts when it comes in contact with the molten metal 50.

On the other hand, the thin plate cover 100 is formed in a thickness of about 50 micrometers, preferably about 30 micrometers to 0.1mm, if the thickness is too thick, the thin plate cover 100 closely adheres along the curved surface of the casting roll (3) It can't be.

Further, the thin plate cover 100 should never have low melting point plating such as zinc or tin plating, because the plated steel sheet generates secondary pollutants as the plated layer is evaporated by the high temperature of molten steel.

At this time, the thin plate cover 100 after adjusting the length in the state that given a certain free space on the molten surface 50, the upper end portion bolted integrally as a bracket 112 to the closed curtain 11 installed in the surface cover (7) (110) Fixing, in particular, the thin magnetic plate 108 is attached to the center portion of the thin plate cover 100 so that the cover plate 100 is spaced apart from the casting roll (3), the above-mentioned contaminated gas 40 or edge dam powder Is closely prevented from adhering to the surface of the casting roll 3.

That is, although briefly shown in the drawings, the thin plate cover 100 is stretched in the longitudinal direction of the casting roll 3 on the thin plate cover 100 and the magnetic plate 108 of the appropriate thickness is attached to the magnetic plate 108 by the magnetic force of the magnetic plate 108. ) Is in close contact with the casting roll 3 in a proper state.

Next, FIG. 3 shows a second embodiment of the casting roll surface covering device of the twin roll thin caster according to the present invention. The cover device of the second embodiment is characterized in that the cover sheet 100 as the first embodiment is a metal plate. Fabrication and installation work is easy, but since it dissolves when it comes into contact with the surface of the molten metal 50, the lower part of the molten metal can not completely cover the surface of the casting roll 3 by giving a certain amount of free space on the surface of the molten metal. An example is the use of a soft, ie, cloth covering means 100 ′ capable of contacting the molten surface 50.

In this case, the second cover means 100 ′ uses one of a fire-resistant cloth made of alumina or silica-based fiber or carbon cloth made of carbon fiber, which is resistant to high temperature, which is covered on the surface of the casting roll 3.

In addition, the cloth cover 100 'is also fixed to the upper end of the bolt 110 as a bracket 112 to the closed curtain 11 of the bottom cover 7, in particular, the bottom of the bottom cover 7 bolts 106. ) Pressing the cloth cover 100 ′ by adjusting the length of the half arc-shaped fixing member 104 integrally formed at the lower portion of the fixing plate 102 to be fixed, thereby more stably in close contact with the entire surface of the casting roll 3. The length of the fixing member 104 is appropriately adjusted so that the cloth cover 100 'does not bite in a state in which the cloth cover 100' is too close to prevent the cloth cover 100 'from being easily worn out due to overfriction.

Next, FIG. 4 shows a third embodiment of the cast roll surface covering device of the twin roll sheet casting machine of the present invention. The third embodiment is characterized in that the thin plate cover 100 of the first embodiment is easy to install and handle. Since it is easy and hard, there is little deformation, but since it cannot contact the molten surface 50, it is difficult to cover the complete casting roll 3, and in the case of the cloth cover which is the second cover means 100 ', it is cast to the molten surface 50. It is possible to cover most of the roll (3) to more reliably prevent the contaminant gas 40 and the edge dam dust attached to the casting roll (3),

That is, the thin plate cover 100 is fixed to the milpe curtain 11 of the bottom surface cover 7 to cover a part of the casting 3, and then the lower side of the thin plate cover 100 contacts the molten surface 50. The cloth cover 100 ′ may be integrally contested.

In this case, the magnetic cover plate 108 is attached to the thin plate cover 100 so that the thin plate cover 100 is closely adhered to the surface of the casting roll 3 and the contaminated gas 40 and the edge dam powder are cast. It is possible to prevent the adhesion to the surface of the roll 3 more efficiently.

At this time, the thin plate cover 100 of the third cover means 100 "and the cloth cover 100 'coupled thereto are also made of carbon steel or stainless steel as in the first and second embodiments, and formed of one of fireproof cloth or carbon cloth. do.

Hereinafter, an embodiment of the present invention will be described.

An example of casting austenitic stainless steel as a twin roll sheet caster, usually 304 stainless steel is an alloy containing 18% Cr-8% Ni. This 304 stainless steel contains about 1% of manganese (Mn) (up to 2%). The melting temperature of manganese is 1244 ° C and when the temperature of molten steel with a temperature of 1500 ° C or above decreases, 40) is discharged.

In this case, the non-oxidizing gas injected into the water surface cover 7 used 100% nitrogen, and of course, nitrogen and argon gas may be mixed or argon gas may be used alone.

When there is no conventional cover means as shown in Figure 1 as a result of the nitrogen was put as a large amount of contaminated gas 40 was discharged in the opposite direction of the casting roll 3 side, but 100% is not completely discharged as the casting time passes The remaining contaminant gas 40 is attached to the casting roll 3 surface to produce black skin on the surface of the casting roll 3 due to the contaminating gas, which is composed mainly of manganese and manganese oxide.

On the other hand, when the thin plate cover 100, that is, the first embodiment of the present invention, that is, two rows of magnetic plates 108 with a thickness of 50 micrometers, the thickness of the black skin was reduced by about 50% at the same time compared to the conventional one, and finally, the thin plate. In the case of the cover 100, it was found that the adherence of the contaminated gas to the casting roll 3 is reduced by about 50%.

Next, when the cloth cover 100 ′ of the second embodiment of the present invention is installed, the black skin thickness of the casting roll 3 is reduced to about 30-40% of the conventional level, and the thin plate cover 100 of the third embodiment of the present invention is provided. In the case where the cloth cover 100 ″ contacting the molten metal surface 50 is installed at the lower portion thereof, the thickness of the black roll of the casting roll 3 is reduced to about 25-35%.

On the other hand, the bulging amount of the slab by the edge dam powder generated by the friction between the casting roll 3 and the edge dam 4 is also reduced by about 50% compared with the conventional.

As described above, according to the casting roll surface covering apparatus of the twin roll thin caster according to the present invention, a contaminated gas mixed with the non-oxidizing gas supplied in the water surface cover and the volatile metal component evaporated from the water surface adheres and solidifies on the surface of the casting roll. There is an advantage in preventing the thickness variation of the solidification shell generated by disturbing the heat transfer.

In addition, there is an effect that the edge dam powder due to the friction between the casting roll and the edge dam is attached to the surface of the casting roll or in contact with the molten metal to prevent the edge bulging caused by the solidification failure.

Therefore, according to the present invention, there is an excellent effect of improving the quality of the cast according to the thickness variation of the solidification shell and the unsolidification of the cast, thereby providing a superior cast.

While the invention has been shown and described with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit or scope of the invention as set forth in the claims below. I would like to know that those who have knowledge of this can easily know.

Claims (6)

Molten steel supplied from the tundish (1) is directed to the molten pool (5) between the casting roll (3) and the edge dam (4), and the non-oxidizing gas is introduced into the molten steel cover (7) provided therebetween. In a twin roll sheet casting machine having an atmosphere layer supplied, It is made of a hard material that is in close contact with the surface of the casting roll 3 of the atmosphere layer to prevent the contaminant gas 40 and the edge dam dust from adhering to the casting roll 3. 1 casting roll surface cover device of a twin-roll sheet caster, characterized in that it comprises a cover means (100) The method of claim 1, wherein the first cover means 100 is composed of a thin plate cover formed of a metal thin plate of one of carbon steel or stainless steel rounded to coincide with the circumferential surface of the casting roll (3), the upper end of which is the bottom cover (7). Bolt 110 is fixed as a bracket 112 to the closed curtain 11 installed to the outside of the), In the central portion of the thin plate cover 100 of the twin-roll thin cast machine, characterized in that it further comprises a magnetic plate 108 to be kept in close contact between the thin plate cover 100 and the casting roll (3) Casting Roll Surface Covering Device Molten steel supplied from the tundish (1) is directed to the molten pool (5) between the casting roll (3) and the edge dam (4), and the non-oxidizing gas is introduced into the molten steel cover (7) provided therebetween. In a twin roll sheet casting machine having an atmosphere layer supplied, The second soft contact the lower end portion is in contact with the surface of the molten metal 50 to be in close contact with the surface of the casting roll (3) of the atmosphere layer to prevent the contaminant gas 40 and the edge dam dust is attached to the casting roll (3) Casting roll surface covering device of a twin roll sheet caster, characterized in that it comprises a cover means (100 ') The method of claim 3, wherein the second cover means (100 ') is composed of a cloth cover made of one of the refractory fabric or carbon cloth covered on the surface of the casting roll (3), the upper end of which is installed to the outside of the water surface cover (7) The bolt 110 is fixed to the closed curtain 11 as a bracket 112, A fixing plate fixed to the upper surface of the center cover of the cloth cover 100 'is fixed to the bolt 106 at the lower portion of the oil floor cover 7 to maintain a close contact between the cloth cover 100' and the casting roll 3. Casting roll surface cover device of a twin roll sheet caster, characterized in that it further comprises a semi-arc fixed member 104 formed integrally at the bottom of (102) The molten steel supplied from the tundish 1 is directed to the molten pool 5 between the casting roll 3 and the edge dam 4, and the non-oxidizing gas is introduced into the molten steel cover 7 provided therebetween. In a twin roll sheet casting machine having an atmosphere layer supplied, The second cover means 100 ′ in close contact with the surface of the casting roll 3 of the atmosphere layer and in contact with the surface of the molten metal 50 to prevent the contaminant gas 40 and the edge dam dust from adhering to the casting roll 3. And the first cover means 100 is integrally coupled to the cast roll surface covering device of a twin roll sheet caster, characterized in that it comprises a third cover means (100 ") installed to cover the casting roll (3). 6. The length of the casting roll (3) at the bottom of the thin plate cover (100) according to claim 5, wherein the third cover means (100 ") is one of carbon steel or stainless steel rounded to coincide with the circumferential surface of the casting roll (3). The fabric cover (100 ') made of one of the refractory fabric or carbon cloth extending in the direction is integrally configured, The thin plate cover 100 is a bracket 112 to the closed curtain 11 installed on the outside of the bottom surface cover 7 as a bolt 110 is fixed, the center roll of the thin plate cover 100 in the casting roll ( 3) Casting roll surface cover device of a twin roll sheet caster, characterized in that the magnetic plate 108 is attached to keep the close contact state between