KR20060000049A - Cooling roll for strip casting of twin roll type - Google Patents

Abstract

The present invention relates to a casting roll of a twin-roll sheet casting machine that can reduce the cost and processing steps by casting the thin plate directly from the molten steel, the object of the present invention is to alternately change the direction of the cooling water of the cooling water hole of the surface of the roll to cool the molten steel By minimizing the temperature difference of the roll surface portion according to the increase in the coolant temperature, it is to reduce the thickness deviation of the slab in the case of uneven expansion in the roll width direction.

According to the present invention, the coolant flows through the upper and lower portions of the roll surface cooling water in one unit so that the cooling water flows, and the cooling water supplied from the upper end of one end passes through the upper end of the other end and again through the upper hole. The hot coolant supplied to the upper end of one end and exiting the other end through the lower end of one end makes the coolant temperature distribution of the roll surface part similar, resulting in uniform roll expansion in the width direction, thereby producing a good slab shape. Provided is a casting roll of a twin roll sheet casting machine.

Lamination Casting Machine, Casting Roll, Twin Roll, Roll Coolant Hole, Roll Thermal Expansion

Description

Cooling roll for twin roll sheet casting machine {COOLING ROLL FOR STRIP CASTING OF TWIN ROLL TYPE}

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

Figure 2 is a schematic diagram showing a casting roll cooling structure of a conventional twin roll sheet caster

Figure 3 is a main part showing a cross-section of the conventional casting roll cooling structure

4 is a main view showing a case where there is only a conventional coolant hole in the upper surface of the roll surface;

5 is a main view showing the lower surface of the cooling water hole in accordance with the present invention;

6 is a main view showing the roll surface portion cooling water direction according to the present invention in comparison with the prior art

Explanation of symbols on main parts of drawing

1: nozzle 2: molten steel

3: casting roll 4: solidification shell

5: thin plate (casting) 6: upper surface hole

7: center hole 8: vertical distribution hole

9 Slope Distribution Hole 10 Slope Distribution Hole Part Annular Cooling Water Path

11: annular cooling water passage of vertical distribution hole                 

12: lower surface hole

The present invention relates to a twin-roll type sheet casting machine that can reduce the cost and process steps by casting the thin plate directly from the molten metal, more specifically, the upper and lower surface of the cooling water hole of the pair of rotating casting rolls to make the cast steel in contact with the molten steel It is for casting roll of twin roll type sheet casting machine to manufacture slab with good shape by minimizing widthwise thermal expansion nonuniformity of casting roll which occurs when cooling water supply direction is one direction by effectively adjusting cooling water flow path .

In general, in the casting method of thin plate, the continuous casting method of manufacturing slab by continuous casting method through molten steel through tundish, rolling and finishing it into thin plate, and the pool of molten steel directly injected between the rotating twin roll and edge dam There is a twin-roll thin plate casting method for directly manufacturing a slab (thin plate) without rolling and finishing the slab as a casting roll through the latter, the latter can be manufactured directly without going through the various processes of the continuous casting method cost side Intensive research has been conducted on the twin roll type sheet casting method as it can reduce the reheating and hot rolling process, which can significantly reduce the cost and consume much energy.

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

That is, as shown in FIG. 1, between the two casting rolls 3 rotating at a constant speed, the molten steel 2 is supplied through an immersion nozzle 1 installed below the molten steel storage container, thereby casting the casting roll 3. And the molten steel (2) supplied through the molten steel pool formed as edge dams on both sides thereof in contact with the casting roll (3) to form the solidification shell (4) while the casting roll (3) rotates, the cast steel (5) is to be cast.

At this time, since the formation of the solidification shell 4 for casting the molten steel 2 into the cast piece 5 occurs while cooling the contact of the casting roll 3 and the molten steel 2, the casting roll 3 is solidified shell ( It is an important facility of sheet casting process that not only determines shape and quality of 4) but also productivity. Casting rolls require solid and hot molten steel of more than 1400 ° C to solidify through a short time of contact, thus requiring a powerful and efficient cooling method. In particular, in the twin roll casting method, since the thickness of the cast steel 5 to be cast is generally a thin plate in the range of 1 to 6 mm, and the cast steel 5 exiting the roll 롤 is almost solidified, the cast quality and shape are problematic. In this case, since there is a side that is almost impossible to calibrate, the thermal expansion phenomenon of the casting roll 3 during casting has an important meaning since it immediately appears in the shape of a cast steel. Therefore, for the casting roll (3) has been studied how to strengthen the cooling to increase the productivity and durability of the roll and the effective cooling method to implement the ideal thermal expansion phenomenon of the casting roll.

2 schematically shows a cooling structure of the casting roll 3, in which a plurality of molten steels 2 supplied from the nozzle 1 of the storage container in which molten steel is stored are circumferentially formed on the surface side of the casting roll 3. Is formed and cooled by the surface upper hole 6 through which the coolant flows. The coolant flow inside the roll is distributed through the central hole 7 of the roll shaft into a plurality of vertical distribution holes 8 extending in a direction perpendicular to the central hole, where the coolant flows into the annular coolant passage of the vertical distribution hole. Through 11) again, it is distributed through a plurality of inclined distribution holes 9, and through the annular cooling water passage 10 of the inclined distribution holes, the cooling water finally flows into the upper surface hole 6 of the surface portion of the roll surface portion. Cooling water having risen by cooling the roll through the upper portion of the surface portion 6 is discharged through the other side of the roll shaft through the inclined distribution hole 9, the vertical distribution hole 8, and the central hole 7 again. .

Figure 3 is a cross-sectional view of the casting roll is a roll having a structure with such a coolant is relatively easy to manufacture and there is no need for a coolant inlet and outflow flow blocking device such as a siphon tube in the center hole of the roll, the production cost is low and the injected coolant There is an advantage in terms of stability that the whole quantity can be supplied through the coolant hole 6 in the roll surface portion without the roll internal leak. However, in the case of such a coolant flow structure, all of the coolant in the roll surface flows from one end of the roll to the other end, and the coolant temperature rises due to the amount of heat taken away during the solidification of the molten steel as the coolant passes through the roll surface. The difference between the one end of the roll and the other end of the cooling water temperature occurs. This temperature difference varies depending on the casting conditions and the flow rate of the coolant, but does not increase the temperature difference, but the occurrence of the coolant temperature difference eventually causes temperature unevenness between the ends of the roll. If the temperature unevenness occurs between the ends of the roll, the thermal expansion of the roll occurs asymmetrically with respect to the center of the roll width. Eventually, the amount of roll thermal expansion between the ends is changed and the shape of the cast slab becomes asymmetrical with respect to the center. This will cause a lot of obstacles in the post processing.

4 shows the temperature at the cooling water holes at both ends when the cooling water direction near the conventional roll surface is one direction, and (a) shows the cooling water supply temperature A of the upper surface hole 6 at one end, and ( b) shows the elevated cooling water temperature B of the surface upper hole 6 of the other end.

In order to solve the problem caused by the one-way cooling water flow, as in Utility Model Application 1998-0038078, 1999-0026813, etc., it is possible to attempt to alleviate the asymmetric thermal expansion phenomenon of the roll through the differential cooling ability inside the cooling water hole of the roll surface. However, the application of the cooling capacity differential method inside the cooling water hole cannot be changed after the roll is manufactured. Therefore, if the initial part of the roll and the thermal load conditions of the roll are different from those expected during manufacturing, the desired purpose cannot be sufficiently achieved. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to improve the above-described problems, and an object thereof is to provide a difference between the cooling water temperature differences at both ends of a roll when the direction of the cooling water in the surface of the cooling water in the roll surface is one direction in the case of a casting roll during a twin roll sheet metal casting process. The direction of the coolant in the coolant hole near the surface of the roll is suppressed in order to suppress the roll thermal expansion asymmetry caused by the occurrence of the roll and consequently, the thickness of the slab becomes asymmetric about the center and causes a problem in post-treatment. In other words, it is made in both directions so that the thermal expansion of the roll is symmetric about the center, and ultimately, to produce a cast having a good shape for post-treatment.

In order to achieve the above object, in the present invention, the cooling water holes near the roll surface are not formed in a single row as in the prior art, but are formed in two rows of upper and lower surfaces so that the two upper surface holes 6 and the lower surface holes 12 1 are formed. The dog roll is provided in a set to provide a casting roll in which the cooling water supplied from one end is supplied to the other end from the other end and then supplied to the other end again.

Moreover, in this invention, the center part of the center hole 7 of a roll shaft is clogged, and simultaneously provide the casting roll which there is no possibility of water leakage.

Figure 5 is a main view showing the casting roll of the twin-roll sheet caster to remove the cooling water temperature difference effect at both ends in the roll surface portion according to the present invention, Figure 6 is a schematic diagram showing the flow of the cooling water (a) is a conventional roll It is a surface part cooling water direction, (b) is a roll surface part cooling water direction of this invention.

The present invention is designed to solve the roll width direction thermal expansion asymmetry phenomenon inevitably generated when the direction of the coolant to the other end is constant at one end of the roll, and the cooling water supply direction at the roll surface is alternately The two upper surface holes 6 are alternately arranged so that the cooling water is alternated, and the coolant supplied from one end to the other end flows back to the other end through the lower surface hole 12, thereby greatly changing the existing roll cooling structure. And symmetrical the temperature of the roll surface portion.

The use of a two-row coolant hole arrangement in such a surface portion not only ensures the widthwise temperature uniformity of the intended roll surface portion, but also adds another surface portion lower hole 12 processed at the bottom thereof. In this cooling water hole, there is almost no increase in the cooling water temperature, so that a uniform temperature can be ensured at the full width of the roll. Thus, the effect of making the roll temperature distribution constant in the width direction can be achieved under the lower cooling water hole. It is possible to configure a casting roll that can ensure a temperature.

Hereinafter, the effects of the present invention will be described with reference to cooling water temperature examples. 4 shows a conventional cooling water hole configuration, the cooling water at the temperature A is supplied to one end and reaches the other end across the roll surface, resulting in temperature B due to the temperature rise, and thus the temperature difference between both ends becomes (BA). The difference in thermal expansion amount corresponding to this temperature occurs.

However, in Fig. 5 showing the configuration of the cooling water hole of the present invention, the cooling water, which is the temperature B at the other end in (b), flows back to one end of (a) to become the temperature of C, and thus the temperature at one end is (A + C) / 2, and at the other end, the temperature (B + B) / 2. By the way, the cooling water temperature difference is equal to (B-A) = (C-B) when passing through the roll surface portion, and as a result, 2B = A + C, so that the same temperature can be secured at both ends and in the roll width direction.

When the coolant at the temperature C flows back to the other end, it passes through the lower surface of the roll surface 12, so that the amount of heat introduced into the surface of the roll is almost absorbed through the upper surface of the surface 6, so that the temperature rise is almost There will be no. In addition, when the coolant of a constant temperature is supplied through the lower coolant hole 12, a side effect of equalizing the roll temperature below the lower coolant hole 12 may be generated, and thus a more stable effect may be expected from the roll expansion side.

As described above, according to the casting roll of the twin roll type sheet casting machine having a cooling water hole configuration, the cooling water supply direction at the upper surface of the cooling water hole of the roll surface of the present invention is bidirectional and the cooling water direction at the lower cooling water hole is uniform in one direction. As a result, the roll temperature distribution becomes uniform in the roll width direction, and as a result, the roll width direction thermal expansion phenomenon is symmetrical, and thus the cast slab can secure a shape suitable for post-treatment.

Claims (2)

In the casting roll 3 which is a wide width roll of a fixed width of a twin-roll type sheet casting machine, Cooling water temperature is different in the surface of the casting roll roll, but the cooling water supply direction is alternating to ensure a uniform temperature distribution, and the cooling water supply direction is one surface or lower surface hole through which the cooling water is constant. 12) casting rolls of a twin-roll thin cast machine, characterized in that the two rows arranged in a row to ensure a uniform temperature in the roll width direction. The casting roll (3) according to claim 1, wherein the casting roll (3) is clogged at the center of the center hole (7) of the roll shaft, so that there is no possibility of water leakage.

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