JPH0341878Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention aims to improve the combination structure of a horizontal mold and its related components in horizontal continuous casting.
In particular, the present invention relates to mold-related equipment that includes improvements to effectively prevent various adverse effects on slabs and casting operations caused by foreign substances such as slag that are caught in the pouring flow of molten steel from a tundish and enter the mold.

(Prior art) Horizontal continuous casting differs from other continuous casting methods in that the mold is held horizontally and connected directly to the pouring port at the bottom of the side wall of the tundish. The pieces are successively pulled out horizontally using pinch rolls in a pulling operation accompanied by oscillation.

(Problem to be solved by the invention) Therefore, at the start of casting, when pouring molten steel into the tundish from a ladle brought above, slag and other tundish brick debris in the molten steel are mixed with the flow of molten steel. , dirt, and other foreign matter are likely to get caught in the mold. Slag, etc. caught in the mold floats to the surface and adheres to the inner surface of the mold, reducing the cooling ability and increasing the pulling force of the slab, causing double skin on the slab, resulting in surface roughness, blowholes, and slag. This causes various adverse effects such as breakout, ie, discharge of internal unsolidified molten steel due to cracks in the slab.

JP-A No. 58-163551 and JP-A No. 58-187240 discuss the phenomenon and adverse effects of slag entrainment and propose measures to prevent it. After the tundish is closed, the molten metal level in the tundish rises and the slag floats, and then the closing member is removed and casting begins. The action and effect are not stable due to the burden placed on them, and they are powerless against the slag that has passed through it and been drawn into the mold due to border control measures taken before it flows into the mold. The essential problem remains.

(Means, effects, and embodiments for solving the problem) In order to solve the problem of slag entrainment in horizontal continuous casting, the present invention differs from the above-mentioned conventional technology in that it solves the problem of slag entrainment in the mold. This traps the slag inside the slab and ultimately stops the slag just before it develops an adverse effect. That is,
In order to collect slag, etc. that were caught in the molten steel pouring flow and entered the mold in the early stage of casting, inside the slab so that they do not reach the inner wall of the mold, a protrusion is provided on the front surface of the dummy bar. The invention is characterized in that a slag floating prevention cover is attached to the upper part of the head pin, which extends in the tundish direction at a distance from the inner surface of the mold.

Hereinafter, the present invention will be explained in detail with reference to the embodiments shown in the accompanying drawings.

FIG. 1 shows, in a longitudinal cross-sectional side view, a portion of a horizontal continuous casting equipment including a mold-related device according to an embodiment of the present invention, in a set state at the start of casting. A mold 1 having a water-cooling jacket is fixedly installed on a base 2 in a horizontal arrangement, and the opening at the right end in the figure faces the casting port 4 at the bottom of the side wall of the tundish 3, and has a break ring 5 made of refractory material and a feed nozzle. It is connected to the casting spout 4 of the tundish via 6.

At the start of casting, the dummy bar body 7 is inserted into the mold 1 from the opening at the other end. Dummy bar body 7
As shown in FIG. 3, a sealing material 8 made of a refractory material is attached to the front surface of the mold 1 by a sealing cover 9, which is cast in contact with the inner wall of the mold 1 to prevent insertion of molten steel. As shown in FIG. 2A or 2B, these shapes correspond to molds with square or round cross sections. In this embodiment, a dummy bar C is constituted by the dummy bar body 7, the seal material 8, and the seal presser cover 1. A head pin 10 is provided to protrude forward from the center of the seal presser cover 9. The molten steel poured into the mold 1 encases the head pin, solidifies, and is integrally joined with the dummy bar C to form the tip of the continuous slab.

In the present invention, a slag floating prevention cover 11 made of a steel plate or a steel pipe divided body is placed on the front side of the dummy bar C.
is attached to the top of the head pin 10. As shown in the figure, the slag floating prevention cover 11 is welded at the base near the upper part of the seal presser cover 9 and attached in a cantilevered manner so as to extend in the tundish direction. It has a concave cross-sectional shape so that it is separated from the inner surface of the mold 1 by a relatively small distance that does not impede the inflow of molten steel.

In the device of the present invention having the above configuration and settings,
At the start of casting, the molten steel A that flows from the tundish 3 through the openings of the pouring port 4, feed nozzle 6, and break ring 5 into the mold 1 and into the front surface of the seal presser cover 9 starts to solidify, but is mixed into the molten steel. Inclusions B that have a specific gravity smaller than that of molten steel, such as slag, tundish brick fragments, garbage, etc.
The slag floats to the surface during the solidification process and, as shown in FIG. 3, gathers below the slag floating prevention cover 11 and solidifies there. In this way, the slag from most of the initially inflowing molten steel below the slag floating prevention cover 11 is prevented or reduced from being collected under the cover 11 and floating to the inner surface of the mold 1, and the slab It will be molded inside. Even if the slag tries to float from the front end of the cover 11, a solidified shell has already been formed and it will not reach the inner surface of the mold. Various negative effects caused by slag adhesion to the mold inner surface are effectively prevented at the final stage within the mold.

The tip portion of the slab containing the slag, cover 11, and pin 10 that is generated at the start of casting is cut off as a crop and has no bearing on the yield. By implementing the present invention, a remarkable result was obtained in which the breakout caused by the above-mentioned slag adhesion to the inner surface of the mold was prevented by more than 95%.

(Effects of the invention) As described above, according to the invention, the following effects can be achieved.

() Improved slab quality.

() Improved operational stability.

() The slab yield is improved.

() The structure is simple, does not require much effort, and costs are low.

[Brief explanation of the drawing]

Figure 1 is a vertical side view of a mold-related device implementing the present invention, Figure 2A is a front view of the dummy bar for a square mold, Figure 2A is a front view of the dummy bar for a round mold, and Figure 3A is a front view of the dummy bar for a round mold. The figure is a longitudinal cross-sectional side view of the upper half of the mold, showing the solidified state inside the mold at the start of casting. 1...Mold, 2...Base, 3...Tandatetsu, 4...Cast, 5...Break ring, 6
...Feed nozzle, 7...Dummy bar body, 8
...Seal material, 9...Seal presser cover, 10...
...Head pin, 11...Slag floating prevention cover,
A... Molten steel, B... floating slag, C... dummy bar.

Claims (1)

[Scope of utility model registration request] A slag floating prevention cover extending in the tundish direction at a distance from the inner surface of the mold is attached to the upper part of the head pin that is protruded from the front surface of the dummy bar that is inserted into the horizontal mold at the start of horizontal continuous casting. A mold-related device for horizontal continuous casting, which is characterized by: