JP2507869Y2 - Centering structure of the break ring for continuous casting - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION This invention relates to a mold for intermittently withdrawing molten metal supplied from a tundish to continuously cast a metal such as steel to obtain a slab, and particularly to improve quality. The present invention relates to a centering structure of a break ring portion having excellent centering performance.

[0002]

2. Description of the Related Art In continuous casting, molten metal stored in a tundish is supplied to a cylindrical mold tube (also referred to simply as "mold"), where it is cooled by a water cooling jacket and at least the outer periphery is This is performed by forming a solidified slab (solidified shell) and intermittently withdrawing the slab with a drawing device provided on the downstream side of the mold.

In such continuous casting, the mold is usually separated from the break ring after one charge and repeatedly used a plurality of times, but the break ring is significantly damaged and is replaced with a new one after each charge. . Therefore, the centering of the break ring or the like must be performed each time.

Therefore, in order to facilitate centering and the like, FIG.
A mold having a feed nozzle structure including a break ring (refractory for connection) as shown in Fig. 1 has been proposed (see Japanese Utility Model Publication No. 1-17405). In the conventional example of FIG. 7, a feed nozzle 3A, a break ring 3B and a mold tube 4 which are separate from the feed nozzle 3A are concentrically connected to each other. As for the connection between the break ring 3B and the mold 4, as shown in FIG. 7, the inner diameter of the break ring 3B is smaller than the inner diameter of the mold 4 in consideration of wear and the like. The molten steel sent from the tundish 1 is cooled by passing water through the water cooling jacket 5,
Solidification starts from the rear end of the break ring 3B, and the solidification shell S increases as the contact length with the mold 4 increases.
Gradually increases in thickness. In this way, continuous casting is performed by intermittently withdrawing the molten metal in the direction of the arrow (casting direction) while solidifying the molten metal from the outer peripheral side, and while repeating the push-back and withdrawal operations by the pinch roll (not shown) on the right side in FIG. It is designed to be linearly drawn to form a slab.

As is clear from the above description, a large thermal stress is generated on the rear end surface (the portion having the step δ) of the break ring 3B, which is the solidification start point of the molten steel, and the impact due to the withdrawal and push-back of the slab is caused. Break ring 3B
Since wear (heat loss) on the inner surface of the mold is remarkable, the mold 4, the feed nozzle 3A, the break ring 3B, and the like are removed for each charge, and at least the break ring 3B is replaced and reassembled.

[0006]

As described above, in the fitting of the break ring 3B and the mold 4, as shown in FIG. 7, the inner diameter of the break ring is smaller than the inner diameter of the mold, that is, a considerably large step δ is formed between them. It is attached with the following problems. The large step between the mold 4 and the break ring 3B is
It becomes a linear surface defect almost as it is, and this surface defect is
When wire drawing is carried out by roll rolling or die drawing, there arises a problem of surface scratches or disconnection of the product, and this defect needs to be removed by a grinder, a cutting tool or the like. The inner diameter of the break ring is larger than the inner diameter of the mold,
That is, if the step is large, the drawing resistance when the shell solidified on the inner surface of the break ring 3B passes through the inlet of the mold 4 becomes large, and the shell solidified during one cycle of drawing breaks at the thinnest point and casting becomes impossible. As is clear from the above, the misalignment between the mold 4 and the feed nozzle 3A or the break ring 3B causes an increase in linear surface defects or causes casting failure. In the above-mentioned conventional example, the fixing member 12 is provided to eliminate the misalignment, but this is performed by the feed nozzle 3A and the break ring 3.
Combined with the fact that B is a separate body, the number of members is rather increased to increase the labor of attachment / detachment, which adversely affects the operating rate of the equipment. Also, the greater the number of members, the greater the possibility of misalignment between them.

Since the inner surface of the break ring 3B is straight, a large step δ is formed on the rear end surface of the break ring 3B, and a large external force or thermal shock directly acts only on this step portion to locally break the break ring. There is the inconvenience of increased damage.

In view of the above situation, the present invention aims to provide a centering structure for a break ring portion, which reduces the number of members in the break ring portion, facilitates centering, and reduces surface defects of the product. To aim.

[0009]

In order to achieve the above object, the centering structure of the break ring portion for continuous casting of the present invention is a continuous casting in which a tundish and a mold are hermetically connected via a feed nozzle and a break ring. Contact elephants equipment cast
There are, one break ring and without by integrating the feed nozzle and a break ring, insert the break ring to the inside of the tundish nozzle, the break phosphorus
The shape of the inner surface of the front half of the gullet expands toward the tundish side
The inner surface shape of the second half that is continuous with the first half is tapered.
In addition to forming a taper that expands in diameter in the manufacturing direction,
Through the engagement step provided on the break ring or mold
Or centering is performed via the tapered surface provided on both sides.
Characterized by the fact that

[0010]

In the above structure, the step difference between the mold tube and the break ring can be reduced, and a product with few surface defects can be manufactured. As a result, an improvement in production yield can be expected. Further, since the break ring is fitted into the mold tube, the centering is easy and the mounting time can be reduced, and the centering does not occur even if an external force is applied when the mold is mounted on the tundish. The step on the rear end surface of the break ring, which is the solidification start point of the molten steel, is extremely small, and the inner surface is formed in a tapered shape, so the impact force due to the withdrawal and pushback of the cast piece acts on the entire tapered surface. Moreover, the pullout resistance is also reduced.

[0011]

[Example 1]

FIG. 1 is a first embodiment of the present invention and shows a vertical sectional view of a mold for a horizontal continuous casting facility. In the figure, a conventional feed nozzle and a break ring are integrated with a tundish nozzle 2 provided on a lower side wall of a tundish 1, and a mold tube (mold) 4 is concentrically sealed to the break ring 3. It is connected.

A water cooling jacket 5 is provided on the outside of the mold 4, and cooling water is introduced from an inlet 6 toward an outlet 7. When the break ring 3 and the mold 4 are connected and fixed, the flange 3b of the rear end 3a of the break ring 3 is engaged with the engagement step 4b provided on the connecting side (flange) 4a of the mold 4. Centering is easy. A holding plate 8 is provided at the front end of the flange 3b of the break ring 3, and the break ring 3 and the mold 4 are fastened and fixed by a fixture 10 installed between a fixing plate 9 provided on the mold 4. . By removing the fixture 10, the mold 4 together with the break ring 3 can be easily separated from the tundish 1.

The shape of the inner surface of the break ring 3 is reduced from the tundish nozzle 2 to a conical shape 3c and expanded from the position of the approximately flange 3b to a tapered shape 3d toward the downstream side in the casting direction (arrow). There is. The inner diameter at the rear end position 3a has a very small step δ between the inner surface and the inner surface of the mold 3.
The inner diameter of the mold 3 is slightly smaller than that of the mold 3. By forming the inner surface of the rear portion of the break ring 3 in a tapered shape, the step δ can be suppressed to a small value of about 0 to 0.3 mm. With such a level difference, surface defects are minimized and quality is not affected. Further, if the inclination angle θ of the tapered surface 3d is set to about 0 to 30 °, peeling of the solidified shell S is promoted. On the contrary, when θ> 30 °, the inner diameter of the break ring 3 becomes small, and an inverse step δ ′ is formed, which is not preferable because the casting product has a remarkable surface defect.

In the above structure, molten steel is supplied from the tundish 1 to the break ring 3 through the nozzle 2, solidification of the molten steel starts from the rear end 3a of the break ring 3, and the heat when the molten steel solidifies is mold. 4 is transmitted to the cooling water. The slab having the solidified layer S formed on the outer peripheral portion in this manner is extracted from the mold 4 by the intermittent drawing (repeating operation of drawing, stopping, and pushing back) by the drawing device (not shown) on the right side.

[Second Embodiment] FIG. 2 shows a second embodiment of the present invention, in which the rear end flange 3b of the break ring 3 is used.
The stepped portion 3e is provided in the stepped portion 3e, and the front end protruding portion 4c of the mold collar portion 4a is fitted in the spigot. Also in this case, the break ring 3 and the mold 4 can be easily centered, and there is little risk of misalignment.

[Third Embodiment] FIG. 3 shows a third embodiment of the present invention, in which the outer peripheral surface of the rear end of the break ring collar 3b is flush with the outer peripheral surface of the tip protrusion 4c of the mold collar 4a, and is extended across both sides. The centering ring 11 is externally fitted. As a result, the resistance to external forces such as thermal shock and pulling out increases, and the prevention of misalignment is enhanced. For easier centering, the mold collar protrusion 4c may be engaged with the step 3f of the break ring 3 as shown in FIG.

[Fourth Embodiment] FIG. 4 shows a fourth embodiment in which a step 3f is formed at the rear end of the break ring collar 3b, and a mold 4 is fitted onto the step 3f. In this case, a step δ is naturally formed between the inner surface of the mold and the step, but the step δ at the tip is 0.3 mm at maximum.
It is set to be about. In this example, since the rear end of the break ring covers the inner surface of the mold inlet, there is an advantage that even if the break ring 3 is worn due to heat loss or the like, no reverse step is formed.

[Embodiment 5] FIG. 5 is a fifth embodiment, in which the inner and outer surfaces of the rear end of the break ring collar 3b are formed into tapered taper shapes 3c and 3d, and molded so as to be in contact with the outer taper surface 3d. The taper surface 4c of No. 4 is brought into contact with the center surface for fitting. There is an advantage that the sealability between the break ring 3 and the mold 4 is improved.

[Fifth Embodiment] FIG. 5 shows a fifth embodiment of the present invention, in which the front half of the break ring 3 has a tapered surface 3c with a reduced diameter and the latter half has a tapered surface 3d with an expanded diameter.
That is the same as in the above embodiment. Furthermore, the outer surface of the rear end of the break ring collar 3b is formed into a tapered taper shape 3g, and the taper surface 4c of the mold 4 is brought into contact with the outer taper surface 3g to perform centering and fitting. is there. There is an advantage that the sealability between the break ring 3 and the mold 4 is improved.

[0020]

Since the present invention is constructed as described above, it has the following effects. In the centering structure of the break ring and the mold tube of the present invention, it is expected that the production yield is improved by reducing the surface defects due to the misalignment. It is possible to reduce the step difference between the mold tube and the break ring, and it is possible to manufacture a cast wire with few surface defects. Since the break ring is engaged with the mold tube (that is, the number of members is small and the structure is simple), the attachment / detachment time can be reduced, and the core is displaced even when the mold is attached to the tundish or when an external force is applied during operation. It is possible to obtain a highly reliable centering structure for the break ring portion. The step on the rear end surface of the break ring, which is the solidification start point of the molten steel, is very small, and the inner surface is tapered, so the entire taper surface receives the impact force due to the drawing and pushing back of the slab. Moreover, the pullout resistance is also reduced.

Needless to say, the present invention can be applied to large-diameter size and vertical continuous casting, but is particularly suitable for horizontal continuous casting equipment for casting small-diameter wire rods.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a continuous casting mold according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of the second embodiment.

FIG. 3 is a vertical sectional view of the third embodiment.

FIG. 4 is a vertical sectional view of the fourth embodiment.

FIG. 5 is a vertical sectional view of the fifth embodiment.

FIG. 6 is a vertical sectional view of the sixth embodiment.

FIG. 7 is a vertical sectional view of a conventional horizontal continuous casting mold.

[Explanation of symbols]

 1 ... Tundish 3 ... Break ring 3d ... Tapered surface (tapered) 4 ... Mold (tube) δ ... Step

Claims (1)

(57) [Scope of utility model registration request] 1. A continuous casting in which a tundish and a mold are hermetically connected via a feed nozzle and a break ring.
In concrete equipment, one of the break ring and without to integrate the feed nozzle and the break ring, plug the break ring to the inside of the tundish nozzle, 該Bu
The inner surface shape of the first half of the rake ring faces the tundish side
Once expanded to a taper shape,
If the surface shape is formed in a taper shape that expands in the casting direction,
Both are engaged on the break ring or the mold.
Centering via the joint part or via the tapered surface provided on both sides
A centering structure for a break ring portion for continuous casting, which is characterized in that