JP2709825B2 - Mold for two-way drawing type horizontal continuous casting machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for a two-way drawing type horizontal continuous caster, and more particularly to a mold capable of extending the life of the mold and reducing the cost of refractories, and more particularly to continuous casting of steel. Used in the field.

[Conventional technology]

In recent years, in the field of continuous casting, instead of the conventional vertical or curved continuous casting method, molten steel has been injected into the mold from the lower part of the tandem, and the slab generated in the mold has been continuously drawn in two opposite horizontal directions. A direction drawing horizontal continuous casting method has been proposed and put into practical use.

JP-A-58-1385 as a conventional two-way drawing type horizontal continuous casting method
44 are disclosed. This method will be described with reference to FIG. That is, the molten steel 4 stored in the tunnel 2 is injected into the mold 8 through the feed nozzle 6. A break ring 10 is set at a portion of the feed nozzle 6 connected to the mold 8, as shown in an enlarged view of FIG. 3, and the mold 8 is provided with a water-cooled copper plate 12 inside. The mold 8 is a system in which a solidification shell or slab 18 is drawn out in two opposite horizontal directions by a pinch roll 16 while vibrating in the horizontal direction left and right by an oscillation device 14.

The flow of the molten steel 4 from the break ring 10 is dominated by the flow in which the downward flow collides with the bottom of the mold as shown in FIG. 3 and is dispersed. The lower end of the ring 10 was often worn annularly. When the lower end of the break ring 10 is worn, the exposed mold wall surface becomes an obstacle, the molten steel flow is disturbed and casting becomes unstable, and the fracture position of the solidified shell, which is the premise of bidirectional drawing, fluctuates and becomes unstable. The productivity decreases and the quality of the slab also deteriorates. In addition, the exposed water-cooled copper plate 12
In this case, cracks were generated, and the life of the mold was extremely reduced, which was a serious problem.

Even if the amount of wear d of the break ring 10 is about 1 mm, the above-described obstacles occur, so that the break ring 10 is conventionally made of an expensive material such as BN-Si ₃ N ₄ , and The wear cannot be prevented.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mold for a bidirectional drawing type horizontal continuous caster capable of solving the above-mentioned problems of the prior art and performing stable casting even when the lower end of the break ring is worn.

[Means and actions for solving the problems]

The gist of the present invention is as follows. That is, while continuously supplying molten steel into the mold through a feed nozzle fitted in a vertical hole provided at the center upper portion of the mold, a two-way drawing of a slab is continuously performed in two opposite directions of the mold. In the mold for a drawing-type horizontal continuous casting machine, between a break ring connected to a lower end of the feed nozzle and annularly fitted to the upper center of the mold, and an inner surface of the mold horizontal portion extending left and right from the lower end of the break ring. And a smooth slope formed in the mold for a two-way drawing type horizontal continuous caster.

The details of the present invention will be described with reference to the embodiment shown in FIG. The lower end of the feed nozzle 6 is provided with a break ring 10 made of a fire-resistant and wear-resistant material having an extended shape. Accordingly, as shown in FIG. 1, the break ring 10 is provided with a vertical hole formed in the upper center of the mold 8.
The lower end of 20 is provided in a state of being annularly fitted to the upper center of the mold 8. Further, in the mold of the present invention, as shown in FIG. 1, a smooth inclined surface 22 is formed extending from the lower end portion of the break ring 10 in contact with the mold to the left and right and the inner surface of the horizontal portion of the mold 8 so as to expand. Is the feature. That is, the inclination angle θ between the inclined surface 22 at the lower end of the vertical hole 20 and the horizontal plane is
A range of 20 to 70 degrees is desirable. Further, the radius R ₂ of the intersection of the upper radius below the horizontal plane of R ₁ and slope 22 of intersection of the vertical plane of the inclined surface 22 are both 2mm or more is desirable. When the inclination angle θ of the lower end slope 22 of the vertical hole 20 of the mold 8 and the radii R ₁ and R _{2 of the} intersection satisfy the above conditions, even if the lower end of the break ring 10 is slightly damaged, the break ring
Since the solidified shell 18 generated at the fitting portion between the mold 10 and the mold 8 is smoothly pulled out, instability of casting and local wear of the mold can be prevented.

In the present invention, even if the amount of wear d at the lower end of the break ring 10 during operation is about 5 to 10 mm and the mold surface is exposed to molten steel, the lower end of the vertical hole of the mold has a smooth shape that widens divergently. In addition, since the solidified shell 18 is smoothly pulled out, the broken position of the solidified shell does not vary and stable casting is performed, thereby improving the productivity. On the other hand, the break ring
Since the fitting portion with 10 has a smooth shape, it is less likely to be damaged by the solidified shell.

〔The invention's effect〕

The present invention provides a fire-resistant and abrasion-resistant break ring at the lower end of the feed nozzle at its extended shape, and smoothly between the lower end of the break ring and the inner surface of the mold horizontal portion extending left and right. The following effects can be obtained because the divergent slope is formed.

(A) Even if the lower end of the break ring is melted, stable casting is performed, so that the production amount can be increased and the quality of the slab can be improved as compared with the conventional case.

(B) Even if the lower end of the break ring is eroded, the life of the mold can be prevented from being shortened due to the occurrence of the conventional cracking, and the life can be extended.

(C) Even if the lower end of the break ring is eroded, there is little adverse effect. Therefore, an expensive material such as Al ₂ O ₃ can be used without using an expensive material such as conventional BN-Si ₃ N _{4 for} the break ring. Use was made possible, and the cost of refractories was reduced.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a mold near a break ring according to an embodiment of the present invention, FIG. 2 is a sectional view of a conventional mold for a bidirectional drawing type horizontal continuous caster, and FIG. FIG. 4 is a schematic sectional view showing the wear of the lower end of the conventional break ring. 4 ... molten steel 6 ... feed nozzle 8 ... mold 10 ... break ring 18 ... solidified shell (slab) 20 ... vertical hole 22 ... slope

Claims (1)

(57) [Claims] 1. A method for continuously feeding molten steel into a mold via a feed nozzle fitted in a vertical hole provided at the upper center of the mold while continuously casting slabs in two opposite directions of the mold. In a mold for a two-way drawing type horizontal continuous casting machine to be drawn, a break ring connected to a lower end of the feed nozzle and annularly fitted to an upper center of the mold, and the mold horizontal portion extending left and right from a lower end of the break ring A mold for a bidirectional drawing type horizontal continuous caster, comprising: a smooth slope formed between the inner surface and the inner surface.