JP2002003931A - Blowing porous plug for molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blowing porous plug for molten metal which restrains partial falling-out of a castable refractory layer and profitablly has a long service life. SOLUTION: The blowing porous plug for molten metal is embedded into a refractory layer 2 forming a molten metal holding chamber and blows gas into the molten metal W in the molten metal holding chamber. The blowing porous plug is constituted of a plug body 50 having blowing passages 59 for blowing the gas into the molten metal W, a cylindrical iron shell 52 surrounding the outer peripheral surface of the plug body 50, reinforcing members 53 integrally fixed on the outer peripheral surface of the iron shell 52 and the cylindrical castable-refractory layer 55 coated on the outer peripheral surface of the iron shell 52 so as to bring into contact with a refractory layer 12. The reinforcing members 53 is embedded into the castable-refractory layer 55 to reinforce the castable-refractory layer 55.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a blown porous plug for molten metal.

[0002]

2. Description of the Related Art In a ladle or the like, a blow-in porous plug for a molten metal is used which is buried in a refractory layer forming a molten-metal holding chamber and blows gas into the molten metal in the molten-metal holding chamber. In this apparatus, when the life of the blow-in porous plug comes to an end, the blow-in porous plug is taken out of the refractory layer and replaced with a new one. The blown porous plug has a plug body made of a refractory material having a blow passage for blowing gas into the molten metal, and a cylindrical iron shell surrounding an outer peripheral surface of the plug body. If the blow-in porous plug is buried in the refractory layer in a state where the steel directly contacts the refractory layer forming the molten metal holding chamber, the blow-out porous plug's shell is affected by the heat of the molten metal and the like. Since it adheres to the refractory layer, it becomes difficult to replace the blown porous plug.

[0003]

Accordingly, a plug body having a blowing passage for blowing gas into the molten metal, a tubular steel shell surrounding the outer peripheral surface of the plug body, and a steel shell so as to contact the refractory layer are provided. A blow-in porous plug having a cylindrical castable layer coated on the outer peripheral surface has been developed. The castable layer is obtained by casting a flowable slurry-like refractory and solidifying it. When the outer peripheral surface of the blown porous plug is covered with the castable layer, the adhesion between the refractory layer and the steel covering the porous plug is suppressed, so that the blown porous plug can be easily pulled out at the time of replacement.

However, during use, cracks may be formed in the castable layer under the influence of the heat of the high-temperature molten metal. If a crack is formed in the castable layer and grows, a part of the castable layer may jump out into the molten metal due to a difference in specific gravity with the molten metal in the molten metal holding chamber, and may float in the molten metal. In this case, the life of the blown porous plug is shortened.

The present invention has been made in view of the above circumstances, and is a blown porous plug capable of preventing sticking of a steel shell to a refractory layer, strengthening a castable layer, and suppressing partial protrusion of the castable layer. The task is to provide

[0006]

A porous plug for molten metal according to the present invention is a porous plug for molten metal which is embedded in a refractory layer forming a molten metal holding chamber and blows gas into the molten metal in the molten metal holding chamber. A plug body having a blowing passage for injecting gas into the molten metal, a cylindrical steel shell surrounding the outer peripheral surface of the plug body, a reinforcing member integrally fixed to the outer peripheral surface of the steel shell, and contacting the refractory layer And a cylindrical castable layer coated on the outer peripheral surface of the iron shell, and the reinforcing member is embedded in the castable layer to reinforce the castable layer.

According to the blown porous plug according to the present invention, the steel shell surrounding the outer peripheral surface of the plug body is not in direct contact with the refractory layer forming the molten metal holding chamber, and is located outside the steel shell. The coated tubular castable layer is in contact with the refractory layer. For this reason, even if the iron shell adheres to the castable layer under the influence of the temperature of the molten metal, the adhesion between the castable layer and the refractory layer is suppressed. Therefore, at the time of replacement of the blow-in porous plug, the blow-in porous plug embedded in the refractory layer forming the molten metal holding chamber can be easily pulled out from the refractory layer and taken out, thereby improving the exchangeability of the blow-in porous plug.

In other words, according to the blown porous plug according to the present invention, the reinforcing member is integrally fixed to the outer peripheral surface of the steel shell. This reinforcing member is embedded in the castable layer and reinforces the castable layer. According to such a blown porous plug according to the present invention, the castable layer covering the outer peripheral surface of the steel shell can suppress the adhesion between the refractory layer and the steel shell.

Further, when the blow-in porous plug is pulled out of the refractory layer forming the molten metal holding chamber and replaced, the castable layer can be given strength so that only the iron shell does not come off.

Further, since the reinforcing member fixed to the outer peripheral surface of the steel shell is embedded in the castable layer, even if a crack occurs in the castable layer during use, even if the castable layer is cracked, the castable layer is separated by the crack. A portion of the castable layer that is damaged by a crack that can suppress the portion from jumping into the molten metal and can prolong the life of the castable layer and thus extend the life of the blown porous plug can easily jump into the molten metal. Is the side closer to the molten metal than the side farther from the molten metal in the castable layer. In consideration of this, according to the preferred embodiment of the molten metal porous plug according to the present invention, the density of the reinforcing member per unit volume of the castable layer is set higher on the side closer to the melt than on the side farther from the melt. Can be adopted. As a result, it is possible to further suppress the castable layer from partially protruding into the molten metal.

[0011] In some cases, the reinforcing member may have a number of protrusions to enhance mechanical engagement with the castable layer. The projection can be configured by winding a wire in a projection shape, for example. Further, the reinforcing member may be formed of a wire wound in a coil shape.

The blowing passage formed in the plug body may have a slit-shaped cross section, a circular shape, or another shape.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 will be described below with reference to FIGS. The ladle 1 according to the present embodiment has a ladle iron shell 11 formed of a container having a bottomed cylindrical shape, and a refractory layer 12 configured using bricks coated on the inner surface of the ladle iron shell 11. And The refractory layer 12 forms a molten metal holding chamber 16. The blow-in porous plug 5 for molten metal according to the present embodiment is integrally embedded in a predetermined portion at the bottom of the refractory layer 12. Injection porous plug 5 for molten metal
The gas is blown into a molten metal W (generally, carbon steel or alloy steel) of the metal in the molten metal holding chamber 16 buried in the refractory layer 12 forming the molten metal holding chamber 16. The molten porous plug 5 is a plug body 5 having a plurality of blowing passages 59.
0, a cylindrical iron shell 5 surrounding the outer peripheral surface of the plug body 50
2, a reinforcing member 53 integrally fixed to the outer peripheral surface of the iron shell 52, and a cylindrical castable layer 55 coated on the outer peripheral surface of the iron shell 52 so as to contact the refractory layer 12. ing.

The castable layer 55 is made of a plug-like main body 5 made of a refractory slurry material (eg, alumina) having fluidity.
It is solidified after casting around the iron skin 52 of No. 0. The plug body 50 has a conical shape with a small diameter on the upper side and a large diameter on the lower side in a vertical cross section, and a flat upper surface 50a facing the molten metal in the molten metal holding chamber 16, a bottom surface 50b, and an outer peripheral surface 50c.
With The blowing passage 59 is for blowing gas into the molten metal W, has a circular cross section, extends along the center axis of the plug body 50, and
It is open at the top surface 50a and at the bottom surface 50b.

The steel shell 52 is provided on the outer peripheral surface 50 of the plug body 50.
c, and has a conical cylindrical shape coaxial with the plug body 50 in a longitudinal section. The iron skin 52 has a thickness t1 of 0.
It is about 5 to 1.5 mm, especially about 1 mm, and is formed of a metal having both heat resistance and strength. Examples of the metal constituting the iron shell 52 include alloy steel such as stainless steel and carbon steel.

The castable layer 55 includes a first castable layer 55 a for covering the outer peripheral surface of the steel shell 52 and the plug body 5.
0 and the second castable layer 55c facing the bottom surface 50b. The first castable layer 55a is thin and has a thickness t2 of about 10 to 30 mm, especially about 15 mm.
It is about 25 mm. Bottom 5 of plug body 50
In 0b, a shallow concave portion 50m is formed. A pool room 50r facing the recess 50m is formed between the bottom surface 50b of the plug body 50 and the second castable layer 55c. A metal blow pipe 59 is embedded in the second castable layer 55c.

The gas supplied from a gas source (not shown) is blown into the blowing passage 59 of the plug body 50 via the blowing pipe 59 and the pool chamber 50r, and the molten metal W in the molten metal holding chamber 16 from the upper end opening 59y of the blowing passage 59. Is blown out.

A reinforcing member 53 is fixed to the outer peripheral surface of the iron shell 52 by welding. The entire reinforcing member 53 is embedded in the castable layer 55 to reinforce the castable layer 55. The reinforcing member 53 is provided on the first side of the castable layer 55.
It is buried from the upper part to the lower part of the castable layer 55a. The reinforcing member 53 is made of a metal having both heat resistance and strength. Examples of the metal constituting the reinforcing member 53 include alloy steel such as stainless steel and carbon steel, but stainless steel is preferable in consideration of strength and corrosion resistance.

As shown in FIG. 2, the upper portion of the reinforcing member 53 has reached near the upper surface 50a of the plug body 50.
The lower portion 53x of the reinforcing member 53 is connected to the bottom surface 5 of the plug body 50.
0b, the second castable layer 5
It has reached around 5c.

As shown in FIG. 2 and FIG.
A first reinforcing member 531 made of a wire or a rod such as a wire extending vertically along the outer peripheral surface of the iron shell 52, that is, along the axial length direction of the plug body 50; 5
2 and a second reinforcing member 53 made of a wire or a rod such as a wire protruding in the radial direction so as to connect the outer peripheral surface of the steel shell 52.
2 and a third reinforcing member 533 made of a wire or rod of wire extending around the outer periphery of the steel shell 52 in the circumferential direction. The reinforcing member 53 has a conical shape as a whole.

The blow-in porous plug 5 is replaced at a considerable frequency. In the present embodiment, as shown in FIG. 2, a steel shell 52 surrounding the outer peripheral surface of the plug main body 50 is not in direct contact with the refractory layer 12, and a cylindrical shape covered on the outside of the steel shell 52. The outer peripheral surface of the castable layer 55 is in contact with the refractory layer 12. Therefore, the castable layer 5
5 and ladle 1 are prevented from sticking to refractory layer 12. Therefore, when replacing the blow-in porous plug 5 already provided in the refractory layer 12 of the ladle 1, the blow-in porous plug 5
Can be pulled out from the refractory layer 12 of the ladle 1 and easily taken out.

At the time of use, as shown in FIG.
The slag 400 is floated on the surface of the molten metal W, and the plurality of graphite electrodes 500 are arranged above the molten metal W to perform arc discharge to heat the molten metal W and perform ladle refining on the molten metal W. At this time, in order to enhance the stirring effect of the molten metal W, a gas such as an inert gas (eg, argon gas, nitrogen gas, etc.)
From the gas supply source 600 via the passage 601
0, and this gas is further blown into the molten metal W to perform a bubbling process.

In this embodiment, the reinforcing member 53 is integrally fixed to the outer peripheral surface of the steel shell 52,
3 is embedded in the castable layer 55,
5 is reinforced. Therefore, when the blown porous plug 5 is pulled out from the refractory layer 12 forming the molten metal holding chamber 16 and replaced, the castable layer 55 may be given strength so that only the iron shell 52 does not come off. it can.

Further, even if the castable layer 55 cracks and grows as the ladle 1 is used more times, the bond retaining ability of the castable portion of the castable layer 55 that has cracked and grows increases the reinforcing member 53. Enhanced by Therefore, it is possible to prevent the castable portion that has grown due to the cracks from jumping into the molten metal W of the molten metal holding chamber 16 of the ladle 1, and the life of the castable layer 55 can be extended. Therefore, the life of the blow-in porous plug 5 can be extended.

Generally, the castable portion broken by the cracks jumps out of the molten metal W on the castable layer 55 on the side facing the molten metal W and closer to the molten metal W than on the side farther from the molten metal W. It is. For this reason, in this embodiment, the density of the reinforcing member 53 per unit volume of the castable layer 55 is set to be higher on the side closer to the melt W than on the side farther from the melt W. Thereby, the castable layer 55
Of the castable portion of the ladle 1 in the molten metal W is further suppressed. Specifically, the number of the second reinforcing members 532, the number of the third reinforcing members 533, and the like are larger on the side closer to the molten metal W than on the side farther from the molten metal W.

(Other Embodiment) FIG. 4A shows a second embodiment.
Of the blowing porous plug 5B. FIG. 4 (A)
As shown in the figure, the reinforcing member 53B is fixed to the outer peripheral surface of the iron shell 52 by welding, and is extended along the outer peripheral surface of the iron shell 52 in the vertical direction, that is, along the axial length direction of the plug body 50. First reinforcing member 531B made of a wire or a rod such as
And a second reinforcing member 532B made of a wire or a rod connecting the reinforcing member 53B and the outer peripheral surface of the steel shell 52, and a C-shape along the outer peripheral surface of the iron shell 52 along the circumferential direction. And a third reinforcing member 533B made of a wire or a bar, such as a wire, extending in an inverted C-shape. The reinforcing member 53B has a conical shape as a whole, and is embedded in the castable layer 55. The blowing passage 59B has a slit shape in cross section.

FIG. 4B shows a cross section of the blow-in porous plug 5C of the third embodiment. As shown in FIG. 4B, the reinforcing member 53 </ b> C is fixed to the outer peripheral surface of the iron shell 52 by welding, and is arranged vertically along the outer peripheral surface of the iron shell 52, that is, along the axial length direction of the plug body 50. A first reinforcing member 531C made of an extended wire or rod, such as a wire;
A second reinforcing member 532C made of a wire or a bar such as a wire connecting the C to the outer peripheral surface of the iron shell 52, and a wire or a rod such as an arc-shaped wire along the outer peripheral surface of the iron shell 52. And a third reinforcing member 533C. Third reinforcing member 533C
Has a number of small projections 539 for further enhancing the engagement with the castable layer 55. The reinforcing member 53C has a conical shape as a whole, and is embedded in the castable layer 55. The blowing passage 59C has a slit shape and a circular shape.

FIG. 4C shows a cross section of the blow-in porous plug 5D of the fourth embodiment. As shown in FIG. 4 (C), the reinforcing member 53D is fixed to the outer peripheral surface of the iron shell 52 by welding, and extends vertically along the outer peripheral surface of the iron shell 52, that is, along the axial length direction of the plug body 50. A first reinforcing member 53D made of an extended wire or rod, such as a wire, is provided. The blowing passage 59D has a slit shape.

FIG. 4D shows a cross section of the blow-in porous plug 5E of the fifth embodiment. As shown in FIG. 4 (D), the reinforcing member 53E is made of a wire or a rod such as a coiled wire.
2 and is partially fixed to the steel shell 52 by welding while being wound around the outer peripheral surface of the steel sheet 2, and is embedded in the castable layer 55. The blowing passage 59E has a circular hole shape.

In each of the above embodiments, the reinforcing members 53B to 53E per unit volume of the castable layer 55 are also provided.
Can be set higher on the side closer to the melt W than on the side farther from the melt W.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be implemented with appropriate modifications as needed without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a sectional view of a ladle in which a blowing porous plug is embedded.

FIG. 2 is a longitudinal sectional view showing a vicinity of a blow-in porous plug buried in a ladle;

FIG. 3 is a cross-sectional view of a blow-in porous plug.

FIG. 4 is a cross-sectional view of the blow-in porous plug according to each embodiment.

[Explanation of symbols]

In the figure, 1 is a ladle, 2 is a refractory layer, 5 is a blown porous plug for molten metal, 50 is a plug body, 52 is an iron shell, 53 is a reinforcing member, and 55 is a castable layer.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F27B 3/22 F27B 3/22 (72) Inventor Naoki Shigematsu 4976 Nomura Minamicho, Shinnanyo-shi, Yamaguchi F term in the Shunan Steel Works of Steel Corporation (reference) 4E004 HA03 4K002 BG02 4K013 CA23 CF13 CF19 4K045 BA01 CA00 RB17

Claims (2)

[Claims] 1. A plug body for a molten metal, which is embedded in a refractory layer forming a molten metal holding chamber and blows gas into the molten metal in the molten metal holding chamber, the plug body having a blowing passage for blowing gas into the molten metal, and the plug body. A cylindrical iron shell surrounding the outer peripheral surface of the steel shell, and a reinforcing member integrally fixed to the outer peripheral surface of the iron shell,
A cylindrical castable layer coated on the outer peripheral surface of the steel so as to contact the refractory layer, and the reinforcing member is embedded in the castable layer to reinforce the castable layer; Porous plug. 2. A blow-in porous plug for molten metal, wherein the density of the reinforcing member per unit volume of the castable layer is set higher on the side closer to the molten metal than on the side farther from the molten metal.