JPH06600A - Pouring nozzle in continuous casting equipment having moving mold wall - Google Patents

Abstract

PURPOSE:To sufficiently slow down a flow rate of molten steel discharged from a pouring nozzle. CONSTITUTION:In the pouring nozzle 4 for pouring the molten steel into a molten steel pouring basin 3 formed between one pair of rolls 1A, 1B and short side weirs 2A, 2B arranged at both ends of these rolls 1A, 1B, a cap 7 is fitted at the lower end of the nozzle body 6, and in the cap 7, side surfaces 15A, 15B faced to both short side weirs 2A, 2B and downward inclining surfaces 17A, 17B are formed. The side surfaces 15A, 15B and the inclining surfaces 17A, 17B are formed of porous refractory brick 9 communicated with the inner and the outer parts. The molten steel is descended in the nozzle body 6 and discharged into the molten steel pouring basin 3 from the side surfaces 15A, 15B and the inclining surfaces 17A, 17B of the cap 7. Then, as the molten steel is passed through the inner part of the refractory brick 9, the discharging flow rate of the molten steel is slowed down and uniformized. Therefore, the development of waving in the enclosing part of the rolls 1A, 1B is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pouring nozzle in a continuous casting facility having a moving mold wall.

[0002]

2. Description of the Related Art Heretofore, as a pouring nozzle of this type, the one disclosed in JP-A-2-220740 can be mentioned. That is, a molten steel reservoir is formed between a pair of mold rolls (hereinafter, abbreviated as rolls) arranged in parallel with each other and a pair of short side weirs arranged in contact with both end faces of both rolls. . Then, a pouring nozzle for guiding the molten steel into the molten steel reservoir is vertically provided from the tundish.

The above-mentioned pouring nozzle has a pipe shape, the lower end of which projects into the molten steel reservoir and the lower end of which is closed. A pair of round discharge ports is formed on the side surface of the lower end portion of the pouring nozzle so as to face each short-side weir. According to this, the molten steel flows downward from the tundish in the pouring nozzle and is horizontally discharged from the discharge port toward the opposing short-side weir.

[0004]

However, according to the above conventional method, as shown in FIG. 6, when pouring the molten steel from the tundish into the molten steel sump 35, the molten steel flows from the discharge port 37 of the pouring nozzle 36. It becomes a strong jet and the short side weir 38A,
Since it hits 38B, a reversal flow (d) is generated, and when this reversal flow (d) flows on the molten metal surface 39, waves are generated at the winding portions of the rolls 40A and 40B, which causes quality defects.

For this reason, it is conceivable to enlarge the discharge port 37 to slow down the flow velocity of the discharge jet. According to this, a large amount of molten steel is scattered during the initial pouring and the roll 40
There was a problem in that the thickness of the slab shell at the solidified portion increased more than the specified thickness due to the adhesion and solidification to A and 40B, which caused uneven thickness. Further, as shown in FIG. 7 and FIG.
Rather than uniformly and uniformly discharging from the discharge port 37,
The lower portion 37b of the upper portion 37a is denser than the upper portion 37a, and becomes a drift (e) that flows at a high speed and is nonuniformly discharged. Therefore, it is not possible to sufficiently slow the flow velocity of the discharge jet simply by increasing the size of the discharge port 37, and a wave is generated by the reverse flow (d) as described above, which causes a quality defect. Was not resolved.

Further, as shown in FIG. 6, since the lower end of the pouring nozzle 36 is closed, the flow of the molten steel stagnates below the pouring nozzle 36 (dotted line part (f)) and the temperature drop occurs. As a result, free crystals are generated, and the central portion of the slab shell is formed thicker than the short-side weirs 38A and 38B, which causes uneven thickness.

Further, as shown in FIG. 9, stagnation (dotted line portion (g)) is generated around the pouring nozzle 36 near the molten metal surface 39, and the reverse flow (d) from the short side weirs 38A, 38B. However, there is a problem that a vortex is generated when it hits this stagnation, and inclusions on the molten metal surface 39 are caught in this vortex and mix into the inside of the slab, causing a defect in the slab. It was

The present invention solves the above-mentioned problems, and the flow velocity of the molten steel discharge jet can be made slow enough to be uniform, and the molten steel flow is stagnant below and around the nozzle. It is intended to provide no pouring nozzle.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a tundish between a pair of moving mold walls arranged in parallel with each other and a weir body provided at both ends of these moving mold walls. A pouring nozzle for pouring molten metal into a molten steel reservoir formed in, a cap is attached to the lower end of the nozzle body, and a pouring surface is formed on the cap facing the both weir bodies and extending downward. The pouring surface is made of a porous refractory material that communicates with the inside and outside.

[0010]

According to the above construction, when pouring molten steel into the molten steel reservoir from the tundish, the molten steel flows downward in the nozzle body and is discharged from the pouring surface of the cap into the molten steel reservoir. At this time, since the molten steel flows through the inside of the porous refractory material forming the pouring surface and is discharged to both the weir body directions and below, the molten steel discharge flow velocity is sufficiently slowed and evened out. Therefore, the generation of waves at the winding portion of the roll is prevented.

Further, the molten steel melt discharged from the pouring surface toward both the weir bodies and below flows from the center of the molten steel reservoir toward both the weir bodies, and the downward discharge flow is reversed at the lower portion of the molten steel reservoir. Becomes an upward flow, and this upward flow causes a gentle flow around the pouring nozzle near the surface of the molten metal. This prevents stagnant flow below and around the pouring nozzle.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIGS. 1 and 2, 1A and 1
Reference numeral B denotes a mold roll (hereinafter, simply referred to as a roll), which is a kind of moving mold walls arranged in parallel to each other, and is rotatably installed around rotation shaft centers 10A and 10B, respectively. At the position between these two rolls 1A and 1B, by cooperation of both rolls 1A and 1B and a pair of short side weirs 2A and 2B (an example of weir body) which are arranged in contact with both end faces of both rolls 1A and 1B. A molten steel reservoir 3 is formed. Reference numeral 4 denotes a pouring nozzle for guiding molten steel from the tundish 5 into the molten steel reservoir 3, which is provided so as to hang down from the tundish 5.

The pouring nozzle 4 is formed of a pipe-shaped nozzle body 6 having an upper end connected to the tundish 5 and a lower end protruding into the molten steel reservoir 3, and a cap 7 attached to the lower end of the nozzle body 6. Has been done. 3 and 4
As shown in FIG. 4, the cap 7 is composed of a casket 8 fitted on the lower end of the nozzle body 6 and a porous refractory brick 9 (an example of a refractory material) attached to the lower part of the casket 8. .

The casket 8 is in the shape of a box whose bottom surface is open, and the lower end of the nozzle body 6 is inserted and fixed to the upper wall 12 thereof. Also, the roll 1 of the casket 8
A pair of side walls 13A and 13B on the A and 1B sides are short side weirs 2A and 2B.
It is formed longer than the pair of side walls 14A, 14B on the B side.

A rectangular parallelepiped upper portion of the refractory brick 9 is fitted between the pair of side walls 13A and 13B, and abuts against the lower surfaces of the other pair of side walls 14A and 14B from below to attach to the casket 8. It is installed. As a result, of the upper side surfaces of the refractory brick 9, the short side weir 2
Side surfaces 15A and 15B facing A and 2B are open and communicate with the inside and outside, and side surfaces 16A and 16B facing the rolls 1A and 1B.
Are closed by the side walls 13A and 13B of the casket 8.

Further, at the lower end of the refractory brick 9, inclined surfaces 17A, 17B are formed so as to incline obliquely upward from the center of the lower surface toward the short-side weirs 2A, 2B and communicate with the inside and outside. Then, the side surfaces 18A and 18B facing the rolls 1A and 1B in the lower part of the refractory brick 9 are closed by, for example, packing a ceramic material 19. The opening ratio of the refractory brick 9 is 30 to
It is set to 60%.

The gap between the upper wall 12 of the casket 8 and the lower end of the nozzle body 6 is sealed by a seal packing 22 using a yarn made of ceramic wool. The upper part of the molten metal surface is covered with a protective cover 23, and the protective cover 23 is externally fitted and attached to the upper end portion of the casket 8. Therefore, the seal packing 22 and the protective cover
The outside air is shut off by 23 and the oxidation of the molten metal surface 24 can be prevented.

The operation of the above configuration will be described below.
When pouring molten steel into the molten steel reservoir 3 from the tundish 5, the molten steel flows downward in the nozzle body 6 and flows into the casket 8 from the lower end. After that, the molten steel flows into the refractory brick 9 and is discharged from the side surfaces 15A, 15B and the inclined surfaces 17A, 17B to both short side weirs 2A, 2B and downward as shown by the arrow (a) in FIG. To do. In this way, the molten steel melt is passed through the inside of the porous refractory brick 9 and discharged, whereby the discharge flow velocity of the molten steel melt is sufficiently slowed and becomes uniform.

Further, as shown by a dotted arrow (b) in FIG. 2, the molten steel is discharged from both sides of the short side dams 2A and 2B and downward, so that the discharged molten steel is discharged from the center of the molten steel reservoir 3 to both sides. While flowing toward the short side weirs 2A, 2B,
As indicated by the dotted arrow (c) in FIG. 1, the downward discharge flow reverses at the lower part of the molten steel reservoir 3 to become an upward flow, and this upward flow is gently around the pouring nozzle 4 near the molten metal surface 24. Generate a flow. This prevents the flow from stagnating below and around the pouring nozzle 4.

In the above embodiment, the nozzle body 6 and the cap 7 may be separable, which facilitates the manufacture of the pouring nozzle 4 and causes severe melting damage.
Only can be replaced.

In the above embodiment, the refractory brick 9 is used.
By appropriately changing the distribution and size of the holes, the discharge flow rate and the flow direction of the molten steel may be adjusted to form a more uniform cast shell 25.

Another embodiment of the present invention will be described with reference to FIG. That is, the lower part of the refractory brick 9 is a curved surface 30 having a radius R.
It was formed in. According to this, the molten steel melts the side surfaces 15A and 15B facing the short side weirs 2A and 2B and the curved surface 30.
Discharge from.

[0023]

As described above, according to the present invention, the molten steel is discharged from the tundish through the inside of the nozzle body and from the pouring surface of the cap into the molten steel reservoir. At this time, since the molten steel flows through the inside of the porous refractory material forming the pouring surface and is discharged to both the weir body directions and below, the molten steel discharge flow velocity is sufficiently slowed and uniformed. become. Therefore, the generation of waves at the winding portion of the roll is prevented, and the quality defect can be eliminated.

The molten steel melt discharged from the pouring surface toward both the weir bodies and below flows from the center of the molten steel reservoir toward both dam bodies, and the downward discharge flow is reversed at the lower portion of the molten steel reservoir. Becomes an upward flow, and this upward flow causes a gentle flow around the pouring nozzle near the surface of the molten metal. This prevents the flow from stagnating below and around the pouring nozzle, and eliminates uneven thickness and defects of the slab shell.

[Brief description of drawings]

FIG. 1 is a view of a pouring nozzle according to an embodiment of the present invention as seen from a direction of a rotation axis of both rolls.

FIG. 2 is a view of the pouring nozzle seen from one roll side.

FIG. 3 is an enlarged vertical cross-sectional view of the cap seen from the rotation axis direction of both rolls.

FIG. 4 is an enlarged vertical sectional view of the cap seen from one roll side.

FIG. 5 is an enlarged vertical cross-sectional view of a cap of a pouring nozzle according to another embodiment of the present invention viewed from one roll side.

FIG. 6 is a view of a pouring nozzle in a conventional example as seen from one roll side.

FIG. 7 is an enlarged vertical sectional view of the lower end of the pouring nozzle.

FIG. 8 is a diagram showing a flow velocity distribution of molten steel melt discharged from a discharge port.

FIG. 9 is a plan view of a molten steel reservoir.

[Explanation of symbols]

 1A, 1B Mold roll (moving mold wall) 2A, 2B Short side weir (weir body) 3 Molten steel reservoir 4 Pouring nozzle 5 Tundish 6 Nozzle body 7 Cap 9 Refractory brick (refractory material) 15A, 15B Side surface (pouring surface) 17A, 17B Inclined surface (Pouring surface)

Claims (1)

[Claims] 1. A pouring nozzle for injecting molten steel from a tundish into a molten steel reservoir formed between a pair of moving mold walls arranged in parallel to each other and weirs provided at both ends of these moving mold walls. A cap is attached to the lower end of the nozzle body, and a pouring surface facing the both weirs and extending downward is formed on the cap, and the pouring surface is a porous refractory material that communicates inward and outward. A pouring nozzle in a continuous casting facility having a moving mold wall characterized by being formed by.