JPS59183960A - Charging method of molten metal - Google Patents

Abstract

PURPOSE:To prevent intrusion of non-metallic inclusions into a molten steel by charging the molten steel from a vessel into an intermediate vessel by using a nozzle having a closed bottom and a lateral opening, and immersing the opening of the nozzle under the bath surface in the intermediate vessel thereby controlling the flow of the molten steel. CONSTITUTION:The bottom 6 of a long nozzle 3 is closed and plural discharging ports 5 for the molten steel having a vertical component in the axial direction are provided in the position slightly higher than the bottom 6. The ports 5 are immersed under the bath surface of the molten steel in the tundish 2. The ports 5 are directed in the direction at a right angle to the charging port 4 of the tundish 2 and the charging flow from the ladle 1 is streamed horizontally in a laminate state from the ports 5 to the side wall 7 of the tundish 2 to form ascending flow which is then acted as the force for floating non-metallic inclusions, gas, etc. The intrusion of the non-metallic inclusions into the molten steel charged into a casting mold is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for injecting molten steel from a long nozzle to facilitate floating of non-metallic inclusions in molten steel within a kundish.

In recent years, non-oxidizing casting methods have been adopted to prevent oxidation of the molten steel flow and prevent non-metallic inclusions and pinholes from forming. For example, when pouring molten steel, a long nozzle is used to block contact between the molten steel being poured and the atmosphere.

As shown in Figure 1, the long nozzle (3) that connects the ladle (1) and the tundish (2) usually opens downward, so the poured molten steel collides with the bottom of the tundish. However, the molten steel from the spout (4) entrains gas and non-metallic inclusions and is poured into the mold from the kundish, which adversely affects the quality of the slab.

The present invention provides a method for press-fitting molten steel into a tundish by controlling the flow of molten steel squeezed out from a long nozzle to prevent nonmetallic inclusions, gas, etc. from being entrained in the molten steel poured from the tundish into the mold. The purpose is to provide.

According to the present invention, the long nozzle is structured to have a bottom and is opened laterally, and the opening is oriented perpendicularly to the molten steel spout of the tundish, or the opening direction is the molten steel spout. However, by directing the water to the weir provided between the discharge port of the long nozzle and the 78 & WJ spout of the Thandi Nosh, non-metallic inclusions within the Kunditsh can be effectively floated and the gas can be absorbed. This was completed based on the knowledge that it is possible to obtain slabs with fewer non-metallic inclusions.

Hereinafter, the present invention will be explained based on the accompanying drawings.

FIG. 2 shows the structure of the long nozzle (3) used in the present invention. As shown in (5), a plurality of discharge ports for the molten steel are opened laterally on the outer peripheral surface of the nozzle. (In the case shown, the bottom part (6) is closed and two pieces are provided on opposite sides of the outer periphery.)The opening position is at a position slightly higher than the bottom part at the tip, 10 to 100 degrees. It is good to provide a laminar flow of molten steel to lift out non-metallic inclusions.

The opening direction can be directed diagonally downward, horizontally, or diagonally upward, as shown in (al, (b), and (C1) in FIG. 2, respectively) according to the shape of the kundish.

FIG. 3(a) is a diagram showing the first embodiment of the present invention, and FIG. 3(b) is a sectional view taken along line I-1 in FIG. 3(a). In the same figure, the long nozzle (3) having the structure shown in FIG.
A discharge port (5) provided at the tip thereof is installed so as to be oriented perpendicularly to the melt & TA spout port (4) of the tundish. Then, it is located at a place shallower than half the depth of the molten steel in the tundish (2).

As a result, as shown by the arrow, the molten steel flow discharged from the discharge port (5) of the long nozzle (3) is transferred to the tundish (2).
) horizontally hits the inclined side wall (7) in a laminar flow state, producing an upward flow, which acts as a floating blade for the nonmetallic inclusions.

FIG. 4 shows a second embodiment of the present invention, in which a weir (
8), and the nozzle (3) and discharge port (5) are directed toward the inner wall of the tundish (2) and the weir (8).

Thereby, the effect of floating non-metallic inclusions due to the upward flow of molten steel can be further enhanced.

In this way, the nonmetallic inclusions in the molten steel float to the surface of the molten steel, and are poured into the mold (not shown) from the molten steel spout (4) provided at the bottom on the opposite side of the tundish (2). Molten steel has less gas absorption and nonmetallic inclusions, and therefore high-quality slabs can be obtained.

The 60-ton capacity tanditsh shown in Figure 3 has a second
b) A comparative example shows the effect of installing a long nozzle (3) with a length of 1000 tm, an inner diameter of 8011 m, and a discharge opening diameter of 80 mm as shown in the figure. If the bottom of the long nozzle is open (Comparative Example 1), even if the bottom of the long nozzle has an opening in the horizontal direction, the orientation direction of the opening is facing the spout of the tundish. This case was compared as (Comparative Example 2).

Table 1 shows the content index of nonmetallic inclusions in the molten steel poured from the tundish when the opening direction of the long nozzle is oriented perpendicular to the molten steel pouring port of the tundish for the conventional long nozzle and the present invention. This is a comparison when using a long nozzle shape.

Table 2 shows the content index of the molten steel poured from the tundish when the opening direction of the long nozzle is directed toward the molten steel spout of the tundish, and a weir is installed between the long nozzle discharge port and the molten steel spout of the tundish. This is a comparison between a conventional long nozzle shape and a long nozzle shape of the present invention.

In addition, in the table, the numerical values represent the content index of nonmetallic inclusions in the molten steel poured out from the tundish.

Table 1 Table 2

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a conventional tundish. Figure 2 shows the structure of the long nozzle used in the present invention,
3 and 4 are the first and second embodiments of the present invention, respectively.
An embodiment of the invention is shown. (11 ladle (2) tundish (3) long nozzle (4) spout (5) (of tundish) discharge port (6) (of long nozzle) bottom (7) side wall (8) weir patent application Representative of Nippon Steel Corporation Masu Tegori (and 2 others) 8 1 'gi] ((1) (b) (C
)6 5 6 plow 3
Gate ((1)

Claims (1)

[Claims] 1. When injecting molten metal from the container to the intermediate container, it has a closed bottom surface and an outflow opening having a vertical component in the axial direction,
and using a nozzle provided at the bottom of the container, the closed bottom surface and the outflow opening being immersed below the bath surface in the intermediate container, to direct the injection flow from the container into the intermediate container. A molten metal injection method characterized in that the flow is upward, thereby causing nonmetallic inclusions to float.