JPH1034319A - Filling material between metal case and refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the filling material between a metal case made of alumina cement which is not softened by insufficient drying or humidity absorption and has sufficient pot life, and the refractory. SOLUTION: The filling material 4 is filled between a metal case 3 having the composition consisting of, by weight, 5-30% alumina cement containing <=2% 12CaO.7Al2 O3 and the balance the powder of the raw refractory material, and the refractory. In addition, 0.02-2 pts.wt. sodium silicofluoride and/or 0.05-2 pts.wt. water-holding agent is added to and blended with 100 pts.wt. filling material as necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a filler between a refractory such as a sliding nozzle plate, an upper nozzle, a lower nozzle, a submerged nozzle or a long nozzle used for continuous casting and a metal case covering the same. ,
It relates to a filler between a metal case and a refractory.

[0002]

2. Description of the Related Art In order to control the flow rate of molten steel in a ladle or a tundish, a sliding nozzle device is generally used. This sliding nozzle device controls the flow rate of molten steel by relatively sliding two or three plate bricks and opening and closing holes for discharging molten steel. Large pressure is applied between the surfaces to prevent leakage of molten steel. This plate brick is made of Al ₂ O ₃ -C
The mainstream material is cracks, rough sliding surfaces, molten steel,
Life is determined by slag melting and the like.

[0003] In order to prevent the cracking of the plate brick due to the pressure or thermal shock, a metal hoop is wound or shrink-fitted around the side of the plate brick, and the back side of the plate brick is in direct contact with the device. In many cases, mortar is applied in order to prevent cracks due to cracks, or a mat with a cushioning property and a tin plate are attached.

[0004] However, there is a strong need for lightening or automating the work of setting the plate brick to the apparatus, and Japanese Patent Application Laid-Open No. 7-251260 discloses a method for setting the plate brick 2 as shown in FIG. A sliding nozzle plate 1 in which a portion excluding a sliding surface is covered with a metal case 3 is described.

[0005] A refractory filler 4 is used between the metal case 3 and the plate brick 2, and is generally made of water glass or aluminum phosphate, etc., which develops strength by heating and drying. Is used.

[0006]

However, between the metal case 3 and the plate brick 2, the filler 4
Since it exists in a state close to hermetic, there is a problem that there is little way for moisture to escape and it is very difficult to dry. Furthermore, these binders have a moisture absorbing function even after drying, and may soften due to moisture absorption when left for a long time. Accordingly, when the filler 4 softens due to insufficient drying or moisture absorption, the softening deformation occurs during use, and the plate brick 2 is pushed into the metal case 3 by the surface pressure, and as a result, a gap is generated between the surfaces. There is a danger of a steel leak accident.

On the other hand, as shown in FIG. 2, the upper nozzle or the lower nozzle 5 used above and below the sliding nozzle plate is also provided with a nozzle outer periphery in order to prevent cracks due to cracks in use and suction of air from the cracks. The metal case 7 is used for the part. Also in this case, generally, a filler 6 using water glass or aluminum phosphate as a binder is used between the metal case 7 and the refractory 8, and like the sliding nozzle plate shown in FIG. Due to insufficient drying or softening of the filler 6 due to moisture absorption, the metal case 7
Opening of the joining surface due to the displacement between the refractory and the refractory 8 may cause a problem.

In order to prevent insufficient drying and softening due to moisture absorption, it is conceivable to use a hydraulic binder such as alumina cement. However, since these have a short pot life, the workability of filling lasts for a long time. There is a problem that cannot be done.

An object of the present invention is to provide a filler between a metal case and a refractory using alumina cement which does not soften due to insufficient drying or moisture absorption and has a sufficient pot life.

[0010]

Filler between the metal case and the refractory of the present invention According to an aspect of the alumina cement 5 to 30 wt% and the balance being a refractory raw material powder is 12CaO · 7Al ₂ O ₃ is less than 2 wt% And, if necessary, 0.1% of sodium silicofluoride per 100 parts by weight of the filler.
It is obtained by adding and mixing 0.05 to 2 parts by weight of 02 to 2 parts by weight and / or a water retention agent.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, attention has been paid to the use of alumina cement as a binder. Alumina cement hardens by a hydration reaction and develops strength, so that water is completely removed by drying. Since there is no need, there is no trouble such as softening deformation due to insufficient drying. Therefore, it is suitable for use in places where drying is difficult such as a gap between the metal case and the refractory. Moreover, once hardened by a hydration reaction, alumina cement has an advantage that almost no softening deformation due to moisture absorption occurs.

However, since the alumina cement reacts with water and hardens, it hardens over time after kneading, and it is difficult to maintain good workability as a filler for a long time. Generally, castables and the like using alumina cement are often used for amorphous refractories, but in this case, since the work is performed immediately after kneading, a pot life of 30 to 60 minutes is sufficient.

However, the work of the filler is performed by applying 1 to 5 mm to the surface of the plate brick, and
Because it is very small, 0-500 g, for example, 20 at a time
Kneading the weight of the kneaded material amounts to 25 to 100 pieces, and it takes 2 to 8 hours to work alone. Therefore,
In the case of a filler using ordinary alumina cement, 30-
Since the work cannot be performed in 60 minutes, it has to be kneaded frequently with a small amount, and there has been a problem that it takes much time and labor.

Representative examples of hydraulic minerals contained in alumina cement include CaO.Al ₂ O ₃ and CaO.2A.
There are calcium aluminates such as l ₂ O ₃ and 12CaO · 7Al ₂ O ₃ . The curing time of the calcium aluminate is as shown in Table 1.

[0015]

[Table 1] Basically 12CaO ・ 7Al_TwoO_ThreeHas a fast hydration rate,
12CaO ・ 7Al_TwoO_ThreeContaining alumina cement
Fillers used are preferred because of their short pot life.
Not good.

Therefore, in the present invention, 12CaO · 7
Alumina cement having an Al ₂ O ₃ content of 2% by weight or less was limited. Basically it is preferable to use an alumina cement containing no 12CaO · 7Al ₂ O _3, the influence also contain long 2 wt% or less is small, up to 2 wt% is acceptable.

The added amount of the alumina cement is 5 to 3
0% by weight is desirable. If it is less than 5% by weight, the strength of the filler is low, and if it exceeds 30% by weight, the explosion resistance during drying deteriorates, which is not preferable.

When sodium silicate fluoride is used as a curing retarder, the pot life can be further secured. The amount added for 12CaO · 7Al ₂ O ₃ content is 2% by weight 5 to 30% by weight alumina cement is less than the filler 100 parts by weight of the balance of the refractory raw material powder 0.02-2 Parts by weight are desirable. If the amount is less than 0.02 parts by weight, a sufficient curing retarding effect cannot be obtained, and if it exceeds 2 parts by weight, the accompanying effect cannot be expected, and waste is produced in terms of cost.

Furthermore, the water retention agent can impart an appropriate ironing and troweling strength, and flows down by its own weight after construction to form an icicle, and after kneading, the liquid phase oozes out of the filler to form aggregates. It is used for the purpose of preventing the binder from separating into a non-uniform structure, and furthermore, as a binding aid. The amount added for 12CaO · 7Al ₂ O ₃ content is 2% by weight 5 to 30% by weight alumina cement is less than the filler 100 parts by weight of the balance of the refractory raw material powder 0.05-2 Parts by weight are desirable. Examples of the water retention agent include wheat starch, potato starch, sweet potato starch, tapioca starch, rice starch, sago starch, mung bean starch, starches such as corn starch and high amylose corn starch, wheat flour, rice flour, corn flour, dried potato flour, cut dried flour. Typical examples include tapioca powder, guar gum, locust bean gum, sanzan gum, karaya gum, agar, seaweed powder, gelatin, carrageenan, and gum arabic, and further include polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), methyl cellulose (MC), and the like. Polymers or dextrins can be used alone or in combination of two or more. When the amount is less than 0.05 part by weight, effective workability cannot be obtained, and when the amount exceeds 2 parts by weight, the strength of the filler decreases, which is not preferable.

The refractory raw material powder used in the present invention includes:
Silica such as silica, silica sand, fused silica, hydrated amorphous silica and anhydrous amorphous silica, mullite, bauxite, ban shale, sillimanite, kyanite,
Alumina such as sintered alumina, electrofused alumina and calcined alumina, raw stone, chamotte, pottery stone, clay, kaolin,
Alumina-siliceous materials such as bentonite, zirconia materials such as zircon and zirconia, electrofused magnesia, sintered magnesia, basic materials such as alumina-magnesia spinel and calcium oxide, chromic materials such as spinel, chromium oxide and chromite, and carbonized Silicon, carbides such as aluminum carbide and zirconium carbide, zirconium nitride, silicon nitride, silicon nitride, nitrides such as boron nitride and aluminum nitride, and raw materials containing carbon include coke, natural graphite, artificial graphite, calcined anthracite, pitch. It is a carbonaceous material such as powder, carbon black, carbon bricks and electrode scraps.In addition to the above, it is necessary to select from the group consisting of all refractory materials such as borides such as boron carbide, silicides such as silicon and ferrosilicon, One type or two or more types can be used together depending on the situation.

The particle size of these refractory raw materials is 0.074 m
m to 60% to 100%. The place of use is the gap between the metal case and the refractory, and this interval is usually around 3 mm. When the refractory raw material has a coarse particle size, it tends to be insufficiently filled, so fine powder of 0.074 mm or less is often used as the raw material. Is preferred. 0.074m
If less than 60% of the raw material is less than m, the filling tends to be defective.

In the filler of the present invention, additives such as an antifoaming agent, a foaming agent, and a workability-imparting agent used for ordinary castables can be used. Further, one or two or more substances can be selected and used from the substances having the same effects as those described above.

The filler according to the present invention has a pot life of 3 hours for a short one and 24 hours or more for a long one at room temperature when kneaded with water, and when heated to 80 to 200 ° C., Sufficient strength is developed within 24 hours. For this reason, softening deformation during use can be prevented.

[0024]

Examples Table 2 shows examples of the present invention, and Table 3 shows comparative examples.

[0025]

[Table 2]

[Table 3] Table 4 shows the mineral composition of the alumina cement used in this example and the comparative example.

[0026]

[Table 4] After kneading the composition consisting of the raw material ratios in Tables 2 and 3, 40 ×
Make a cast sample of 40 × 160mm, 90 ° C
After drying for 24 hours, each physical property was measured. The flow value was evaluated according to JIS, and the pot life was evaluated according to the consistency described in JIS. In addition, to evaluate the degree of softening due to moisture absorption, 4
2 in an autoclave under steam at a pressure of 130 ° C
The compressive strength after the time treatment was measured and compared with the compressive strength before the treatment.

Examples 1 to 11 In Examples 1 to 11 using alumina cement, the compressive strength after the autoclave treatment was higher than Comparative Example 1 using water glass as a binder and Comparative Example 2 using aluminum phosphate. , And there was little softening deformation due to moisture absorption.

The pot life was 3 hours in Example 1 using the alumina cement of the present invention, whereas
Comparative Example 3 using the conventional alumina cement is 1.5 hours, and the present invention can ensure a sufficiently long pot life.

With respect to the addition ratio of alumina cement, the strength was low at 4% by weight of Comparative Example 4 and was not practical, and the pot life was short at 1.5 hours at 33% by weight of Comparative Example 5, resulting in poor workability. It is.

The effect of the sodium silicofluoride used as a curing retarder is not seen at 0.01% by weight (outer portion) of Comparative Example 8.

When the water retention material was 0.04% by weight (outer shell) of Comparative Example 6, the workability improvement effect was small, and 2.2% of Comparative Example 7 was used.
If it is% by weight, the compressive strength is low and it is not suitable.

Embodiment 12 In the sliding nozzle plate 1 shown in FIG.
The filler 4 of Example 5 was filled between the plate brick 2 and the metal case 3. As a result of using 30 sets of the sliding nozzle plates 1 with an average of 4.3 charges in a molten steel pot, no ingots were found between the surfaces, and the results were good.

Embodiment 13 In the lower nozzle 5 shown in FIG.
Was filled between the metal case 7 and the refractory 8. As a result of using 30 lower nozzles and an average of 5.7 charges in a molten steel pot, no damage or the like due to air suction from cracks was observed, and the results were good.

[0034]

【The invention's effect】

(1) Alumina cement is hardened by a hydration reaction and develops its strength, so that insufficient filling or softening deformation of the filler due to moisture absorption does not occur.

(2) By preventing softening deformation, steel leakage from between the surfaces of the sliding nozzle plate can be prevented.

(3) By preventing softening deformation, there is no gap between the joining surfaces of the upper nozzle, so that air suction and steel leakage can be prevented.

(4) Since the pot life is long and the workability does not change, the quality of the filler portion is stabilized.

(5) By using the water retention agent, the sagging of the filler is eliminated and the work efficiency is improved.

(6) By using sodium silicofluoride,
Further, the pot life can be secured, a large amount of filler can be kneaded at a time, and work efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sliding nozzle plate according to a twelfth embodiment.

FIG. 2 is a sectional view of a lower nozzle according to a thirteenth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sliding nozzle plate 2 Plate brick 3 Metal case 4 Filler 5 Lower nozzle 6 Filler 7 Metal case 8 Refractory

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirofumi Sakai 1-1-1, Higashihama-cho, Yawatanishi-ku, Kitakyushu-shi, Fukuoka Inside Kurosaki Ceramics Co., Ltd.

Claims (3)

[Claims] 1. A filling between a metal case and a refractory, characterized in that 5-30% by weight of alumina cement having a content of 12CaO.7Al ₂ O ₃ of 2% by weight or less and a refractory raw material powder for the remainder. Wood. 2. The filler between a metal case and a refractory according to claim 1, wherein 0.02 to 2 parts by weight of sodium silicofluoride is added to 100 parts by weight of the filler. 3. The filler between a metal case and a refractory according to claim 1, wherein 0.05 to 2 parts by weight of a water retention agent is added to 100 parts by weight of the filler.