JP2006231347A - Twin roll type continuous caster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of breakout by preventing the formation of a gap between a step part of a ring-shaped recessed part and a solidified shell. <P>SOLUTION: Recessed rolls 101,102 have the step parts 101a, 101b, 102a and 102b at both end parts and also are formed with the ring-shaped recessed parts 107a, 107b, 109a and 109b near the step parts (step part rising parts 131a, 131b, 132a and 132b). Since the solidified shells 111 and 112 solidified by being cooled with the roll surfaces, enter the ring-shaped recessed parts 107a, 107b, 109a and 109b and get stuck thereon, even if solidified shells 111 and 112 tend to thermally shrink along a roll axial direction, this shrinkage is prevented. As a result, the formation of the gap near the step part is prevented, the heat-exhausting even near the step parts is promoted, the growth of the solidified shell at the position is progressed and the occurrence of the breakout can be prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a twin-roll continuous casting machine, and is devised so that safe operation can be performed without worrying about breakout (breakage of a cast piece) even if a concave roll is adopted as a roll.

  The continuous casting machine continuously casts molten steel that has been refined, and directly produces a slab (slab or strip). The continuous casting method using a continuous casting machine is less segregated and has good surface quality compared to conventional ingot-making and ingot-making methods, and is suitable for producing steel plate slabs.

  As a mold used for the continuous casting machine, there are an asynchronous vibration mold in which the mold does not move with respect to the slab and a synchronous twin-roll mold in which the mold moves.

FIG. 10 shows an example of the vibration mold 01. The molten steel 04 is supplied through the nozzle 03 to the internal space (hot water reservoir) of the mold 02 that vibrates in the vertical direction (vertical vibration). In this example, the mold 02 has a funnel shape, the top opening is bulging (the long side is curved outward), the long side is narrowed from the top to the bottom, and the bottom opening is rectangular. It has become.
In the vibrating mold 01, the molten steel 04 supplied to the hot water pool portion is contacted with the mold 02 to remove heat and become a solidified shell, and is drawn out as a slab 05 from the lower surface of the mold 02. At this time, molten powder is supplied to ensure uniform lubrication between the wall surface of the mold 02 and the solidified shell.

  FIG. 11 shows an example of a twin roll mold 010. In this twin roll mold 010, a pair of rolls 011 and 012 rotating in opposite directions are arranged close to each other in parallel at the same height position, and both ends in the axial direction of the rolls 011 and 012 are roll end faces. It is partitioned by side weirs 013 and 014 (which are not shown in the figure). Molten steel 016 is supplied through an nozzle 015 to an internal space (a hot water pool portion) formed by being surrounded by the rolls 011 and 012 and the side weirs 013 and 014.

  When the rolls 011 and 012 rotate inward with respect to each other (when the molten steel 016 is rotated so as to be wound downward), the molten steel 016 is cooled by coming into contact with the rolls 011 and 012. A shell is formed. Both of these solidified shells grow as the roll rotates, and are pressed and integrated at the minimum gap portions of the rolls 011 and 012 and are taken out as a cast slab 017.

  In a twin roll type continuous casting machine using a twin roll type mold, an example in which the roll shape is devised so as to increase the thickness of the cast slab is shown in JP-A-59-118249. explain.

  FIG. 12 shows a twin roll mold of the twin roll type continuous casting machine disclosed in Japanese Patent Application Laid-Open No. 59-118249, and FIG. 13 is a view taken along arrow AA in FIG.

As shown in FIGS. 12 and 13, a space formed by a pair of rolls 10 and 11, side weirs 12 and 13 that partition the roll end face side, and dams 14 and 15 that are in contact with the rolls 10 and 11 is formed. It becomes a hot water reservoir. Molten steel 16 is supplied to the hot water reservoir.
At both ends of the roll 10, step portions 10a and 10b are formed in a flange shape. Similarly, step portions 11 a and 11 b are formed in a flange shape at both ends of the roll 11.

  When the rolls 10 and 11 are rotated, the molten steel 16 is cooled by coming into contact with the surfaces of the rolls 10 and 11 (including the surfaces of the stepped portions 10a, 10b, 11a, and 11b), and the solidified shells 17 and 18 are brought into contact. Is formed. The solidified shells 17 and 18 grow as the roll rotates. And it formed in the outer periphery of step part 10a, 10b among the solidification shells 17 in the minimum gap part where the clearance gap between step part 10a and step part 11a and the gap between step part 10b and step part 11b become the smallest. The part and the part formed in the outer periphery of step part 11a, 11b among the solidification shells 18 are press-contacted and integrated by the narrow pressure by step part 10a, 10b and step part 11a, 11b. As a result, both ends of the solidified shell 17 and the solidified shell 18 are pressure-welded and integrated, and the solidified shells 17 and 18 are joined in a bag binding shape as shown in FIG. Thus, the slab 19 is obtained.

  The slab 19 in a state in which the solidified shells 17 and 18 are pressed into a bag binding shape at the minimum gap portion and the molten steel 16 is left in the central portion is drawn out of the rolls 10 and 11 and conveyed, and is cooled in the middle of conveyance. As a result, the molten steel 16 in the center portion also solidifies.

  In the example shown in FIG. 12 and FIG. 13, the stepped portions 10 a and 10 b and the stepped portions 11 a and 11 b having a narrow gap can be pressed at the ends of the solidified shells 17 and 18. The slab 17 that can be pressed into a bag binding shape and pulled out from the rolls 10 and 11 is in a molten state at the center, but the peripheral surface is solidified. Become. Thus, since the clearance gap between the rolls 10 and 11 can be widened, the thickness of the slab 19 manufactured can be made thick. Since the thickness of the slab 19 can be increased in this way, the amount of slab production can be increased, and the production of steel plates having various thicknesses can be dealt with.

JP 59-118249 A JP 2002-113557 A

  By the way, when casting is performed with a stepped roll as shown in FIGS. 12 and 13, as shown in FIG. 14, the solidified shell 17 (18) and the stepped portions 10b and 11b of the roll 10 (11) rise. A gap G may occur between the portions. This is because when the solidified shell 17 (18) is formed on the roll surface, the solidified shell 17 (18) shrinks and deforms due to thermal contraction.

  When such a gap G occurs, heat removal does not proceed in this portion, and in the portion of the solidified shell 17 (18) that is in contact with this gap G, the solidified shell does not grow and remains thin. The rolls 10 and 11 may be pulled out, and the thin portion may be reheated and remelted to cause breakout (breakage of the slab).

  In view of the above prior art, the present invention is a case where a concave roll is used in which the diameters at both ends along the roll axial direction are larger than the diameter of the central part of the roll, such as a roll with a stepped portion. However, an object of the present invention is to provide a twin-roll continuous casting machine that can be safely operated without worrying about breakout.

The configuration of the present invention for solving the above problems is as follows.
In a twin-roll continuous casting machine that supplies molten steel between a pair of rotating rolls and draws out a slab formed by pressing a solidified shell solidified on the surface of each roll from the gap between the rolls,
The roll is a concave roll in which the diameter of both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll,
A ring-shaped concave portion extending in a ring shape in the circumferential direction is formed on the circumferential surfaces on both ends of the concave roll.

The configuration of the present invention is as follows.
In a twin-roll continuous casting machine that supplies molten steel between a pair of rotating rolls and draws out a slab formed by pressing a solidified shell solidified on the surface of each roll from the gap between the rolls,
The roll is a concave roll in which the diameter of both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll,
A ring-shaped convex part extending in a ring shape in the circumferential direction is formed on the circumferential surface on both ends of the concave roll.

The configuration of the present invention is as follows.
In a twin-roll continuous casting machine that supplies molten steel between a pair of rotating rolls and draws out a slab formed by pressing a solidified shell solidified on the surface of each roll from the gap between the rolls,
The roll is a concave roll in which the diameter of both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll,
A plurality of independent depressions, a number of independent protrusions, or a number of independent grooves are formed on the peripheral surface of the concave roll.

The configuration of the present invention is as follows.
In a twin-roll continuous casting machine that supplies molten steel between a pair of rotating rolls and draws out a slab formed by pressing a solidified shell solidified on the surface of each roll from the gap between the rolls,
The roll is a concave roll in which the diameter of both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll,
On the peripheral surfaces on both end sides of the concave roll, a ring-shaped concave portion extending in a ring shape in the circumferential direction or a ring-shaped convex portion extending in a ring shape in the circumferential direction is formed,
A plurality of independent depressions, a number of independent protrusions, or a number of independent grooves are formed on the peripheral surface of the concave roll.

The configuration of the present invention is as follows.
The recess includes a plurality of recesses having different sizes, the protrusion includes a plurality of projections having different sizes, and the groove includes a plurality of grooves having different sizes. Roll type continuous casting machine.

  In the present invention, a ring-shaped concave portion or a ring-shaped convex portion extending in a ring shape in the circumferential direction is formed on the circumferential surface on both ends of the concave roll, and therefore a gap is generated between the solidified shell and the stepped portion. The occurrence of breakout at this portion can be prevented.

  In the present invention, a large number of independent depressions, a large number of independent protrusions, and a large number of independent grooves are formed on the peripheral surface of the concave roll, so that a gap is generated between the solidified shell and the stepped portion. Thus, breakout can be prevented from occurring at this portion, and cracking of the slab can be prevented.

Embodiments of the present invention will be described below in detail with reference to the drawings.
Here, the “concave roll” used in the present invention will be described first. A “concave roll” refers to a “roll whose diameter at both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll”.

For example, as the “concave roll”, as shown in FIG. 1A, the roll R has stepped portions D at both ends, and as shown in FIG. 1B, both ends of the roll R are tapered. Having a step portion D, and having a step portion D at both ends as shown in FIG. 1 (c), the roll R has a drum shape whose diameter gradually decreases toward the center in the axial direction. There are various types of rolls.
If such a concave roll is used, the solidified shell can be pressed into a bag-like shape, and the cast piece to be cast can be thickened.

  Hereinafter, embodiments of the present invention will be described in detail based on the respective examples.

  A twin-roll continuous casting machine according to Embodiment 1 of the present invention will be described with reference to FIG. 2 and FIG. 3 which is a view taken along the line BB in FIG.

  In the twin roll type continuous casting machine 100 according to the first embodiment, a pair of concave rolls 101 and 102 rotating in opposite directions are arranged close to each other in parallel at the same height position. Both ends in the axial direction are partitioned by side weirs 103 and 104 which are in close contact with the roll end face. Molten steel 106 is supplied through the nozzle 105 to the internal space (hot water reservoir) formed by being surrounded by the concave rolls 101 and 102 and the side weirs 103 and 104.

  The concave roll 101 has step portions 101a and 101b after both ends of the roll expand in a tapered shape. In addition, ring-shaped recesses 107 a and 107 b extending in a ring shape in the circumferential direction are formed on the peripheral surfaces on both end sides of the concave roll 101. The formation positions of the ring-shaped concave portions 107a and 107b are located on the center side of the step portions 101a and 101b with respect to the roll axis direction, but as far as possible on both ends. That is, the ring-shaped concave portions 107a and 107b are formed at the bases of the step portions 101a and 101b (step portion rising portions 131a and 131b).

  The concave roll 102 has stepped portions 102a and 1021b after both ends of the roll expand in a tapered shape. Moreover, ring-shaped concave portions 109a and 109b extending in a ring shape in the circumferential direction are formed on the peripheral surfaces on both end sides of the concave roll 102. The formation positions of the ring-shaped recesses 109a and 109b are located on the center side of the stepped portions 102a and 102b with respect to the roll axis direction, but as far as possible on both ends. That is, the ring-shaped concave portions 109a and 109b are formed at the bases of the step portions 102a and 102b (step portion rising portions 132a and 132b).

  When the concave rolls 101 and 102 are rotated, the molten steel 106 is cooled by contacting the surfaces of the concave rolls 101 and 102 (including the surfaces of the step portions 101a, 101b, 102a, and 102b), and the solidified shell 111 is cooled. , 112 are formed. The solidified shells 111 and 112 grow as the roll rotates. The gap between the stepped portion 101a and the stepped portion 102a and the smallest gap portion where the gap between the stepped portion 101b and the stepped portion 102b is the smallest are formed on the outer periphery of the stepped portions 101a and 101b in the solidified shell 111. The part and the part formed in the outer periphery of step part 102a, 102b among the solidification shells 112 are press-contacted and integrated by the narrow pressure by step part 101a, 101b and step part 102a, 102b. As a result, both ends of the solidified shell 111 and the solidified shell 112 are pressure-welded and integrated, and the solidified shells 111 and 112 are joined in a bag binding shape as shown in FIG. Thus, the slab 113 is obtained.

  The slab 113 in a state in which the solidified shells 111 and 112 are pressed in a bag-bound form at the minimum gap portion and the molten steel 106 is left in the center portion is drawn out from the concave rolls 101 and 102 and is transported, and is cooled in the middle of transport. As a result, the molten steel 106 in the center portion also solidifies.

In the first embodiment, the ring-shaped recesses 107a, 107b, 109a, and 109b are formed on the peripheral surfaces of both ends of the concave rolls 101 and 102. Therefore, the solidified shells 111 and 112 solidified on the roll surface are the ring-shaped recesses 107a and 107b. , 109a and 109b (see FIG. 4 which is an enlarged view).
Therefore, even if the solidified shells 111 and 112 are thermally contracted and contract along the roll axis direction, the solidified portions that have entered the ring-shaped concave portions 107a, 107b, 109a, and 109b become ring-shaped concave portions 107a, 107b, 109a, and 109b. It is caught and the shrinkage | contraction of the solidification shells 111 and 112 along an axial direction is suppressed.
For this reason, a gap is not generated between the solidified shells 111 and 112 and the step portions 101a, 101b, 102a and 102b, and heat removal at these portions (near the step portions) is not hindered. , 112 progresses and the delay in solidification can be eliminated, and the occurrence of breakout at this portion can be prevented.

  In place of the “ring-shaped concave portion”, a “ring-shaped convex portion” may be adopted.

  In the twin roll type continuous casting machine 100 of Example 2, as shown in FIG. 5, a large number of independent depressions 108 and 109 are formed on the roll surfaces of the concave rolls 101 and 102. For this reason, the solidified shells 111 and 112 solidified on the roll surface also enter the recesses 108 and 109 (see FIG. 6 which is an enlarged view).

Therefore, even if the solidified shells 111 and 112 are heat-shrinked and try to shrink along the roll axis direction, the solidified portion that has entered the recesses 108 and 110 is caught in the recesses 108 and 110, and the solidified shells 111 and 112 along the axial direction. Suppresses shrinkage.
For this reason, a gap is not generated between the solidified shells 111 and 112 and the step portions 101a, 101b, 102a, and 102b, the solidification delay can be eliminated, and the occurrence of a breakout in this portion can be prevented. it can.
Further, since the shrinkage of the solidified shells 111 and 112 is dispersed and uniformized, it is possible to prevent the solidified shells 111 and 112 and hence the slab 113 from cracking.

  Instead of “dents”, a large number of independent “projections” and a large number of independent “grooves” may be employed. In this case, the “dent”, “projection”, and “groove” may each include a plurality of dimensions having different sizes.

  In the second embodiment, a large number of independent depressions 108 and 110 are formed on the surfaces of the concave rolls 101 and 102. However, in the third embodiment, as shown in FIG. A large number of independent large diameter (for example, 1 to 5 mm) depressions 108L and 110L and a large number of independent small diameter depressions (dimples) 108S and 110S are formed on the surface. The size of the small-diameter depressions (dimples) 10 8 S and 110 S is set to a roughness Rz = 90 μm and a diameter of about 0.5 to 1 mm.

  It should be noted that “projections” and “grooves” may be employed instead of “dents”. In this case, the “dent”, “projection”, and “groove” may each include a plurality of dimensions having different sizes.

  In Example 4, as shown in FIG. 8, ring-shaped recesses 107a, 107b, 108a, 108b extending in a ring shape in the circumferential direction are formed on the peripheral surfaces of both ends of the concave rolls 101, 102, and the concave roll A large number of small-diameter recesses 108S and 110S are formed on the surfaces of 101 and 102, respectively.

  In the second embodiment, a large number of independent depressions 108 and 110 are formed on the surface of the concave rolls 101 and 102. However, in the fifth embodiment, as shown in FIG. 9, the circumferential surface of the concave roll 101 (102) is formed. A large number of independent grooves 120 were formed. This groove 120 can provide the same effect as that of the recesses 108 and 110 in the second embodiment.

Explanatory drawing which shows the various examples of a concave roll. The front view which shows the twin roll type continuous casting machine which concerns on Example 1 of this invention. The BB arrow line view of FIG. The block diagram which shows the principal part of Example 1 of this invention. The block diagram which shows the twin roll type continuous casting machine which concerns on Example 2 of this invention. The block diagram which shows the principal part of Example 2 of this invention. The block diagram which shows the principal part of Example 3 of this invention. The block diagram which shows the principal part of Example 4 of this invention. The block diagram which shows the concave roll used for Example 5 of this invention. The block diagram which shows the conventional vibration mold. The block diagram which shows the conventional twin roll type | mold casting_mold | template. The block diagram which shows the conventional twin roll type continuous casting machine. FIG. 13 is an AA arrow view of FIG. 12. Explanatory drawing which shows the generation | occurence | production state of the gap in the past.

Explanation of symbols

100 Twin roll type continuous casting machine 101, 102 Concave roll 101a, 101b, 102a, 102b Stepped portion 103, 104 Side weir 105 Nozzle 106 Molten steel 107a, 107b, 109a, 109b Ring-shaped concave portion 108, 108L, 108S, 110 Recess 111, 112 Solidified shell 113 Cast slab 120 Groove 131a, 131b, 132a, 132b Step rising part

Claims (5)

In a twin-roll continuous casting machine that supplies molten steel between a pair of rotating rolls and draws out a slab formed by pressing a solidified shell solidified on the surface of each roll from the gap between the rolls,
The roll is a concave roll in which the diameter of both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll,
The twin roll continuous casting machine is characterized in that ring-shaped recesses extending in a ring shape in the circumferential direction are formed on the peripheral surfaces on both ends of the concave roll. In a twin-roll continuous casting machine that supplies molten steel between a pair of rotating rolls and draws out a slab formed by pressing a solidified shell solidified on the surface of each roll from the gap between the rolls,
The roll is a concave roll in which the diameter of both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll,
The double roll continuous casting machine is characterized in that ring-shaped convex portions extending in a ring shape in the circumferential direction are formed on the circumferential surfaces on both ends of the concave roll. In a twin-roll continuous casting machine that supplies molten steel between a pair of rotating rolls and draws out a slab formed by pressing a solidified shell solidified on the surface of each roll from the gap between the rolls,
The roll is a concave roll in which the diameter of both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll,
The twin roll type continuous casting machine is characterized in that a large number of independent depressions, a large number of independent protrusions or a large number of independent grooves are formed on the peripheral surface of the concave roll. In a twin-roll continuous casting machine that supplies molten steel between a pair of rotating rolls and draws out a slab formed by pressing a solidified shell solidified on the surface of each roll from the gap between the rolls,
The roll is a concave roll in which the diameter of both ends along the axial direction of the roll is larger than the diameter of the central portion of the roll,
On the peripheral surfaces on both end sides of the concave roll, a ring-shaped concave portion extending in a ring shape in the circumferential direction or a ring-shaped convex portion extending in a ring shape in the circumferential direction is formed,
The twin roll type continuous casting machine is characterized in that a large number of independent depressions, a large number of independent protrusions or a large number of independent grooves are formed on the peripheral surface of the concave roll. In claim 3 or claim 4,
The recess includes a plurality of recesses having different sizes, the protrusion includes a plurality of projections having different sizes, and the groove includes a plurality of grooves having different sizes. Roll type continuous casting machine.

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