JPH05155666A - Molding body for masonry joint - Google Patents

Abstract

PURPOSE:To enable joining of shaped refractories while hot and to exchange immersed nozzles while hot in the continuous casting of steel by using a molding body for masonry joint consisting of a refractory material and a binder and which maintains its shape at ordinary temp. and is plasticized at high temp. CONSTITUTION:A material consisting of 40-90wt.% of the refractory material (having the same composition as the nozzle refractory and tuyere refractory to be joined) and 10-60wt.% of a binder (e.g. thermoplastic resin and/or pitch) is mixed with 0.1-10wt.% by outer percentage of carbon fiber increased to prepare a molding body for the masonry joint. The molding body is heated to about 150 deg.C and made flowable, and the flowable body is press-formed into the shape equivalent to the joint between the tuyere brick 2 of a tundish 1 and an immersed nozzle 3 and having a flange 4 at the upper part, cooled and dried to obtain a cap-shaped molding body 5 for the masonry joint. The molding body is put on the nozzle 3 preheated to about 1000 deg.C, and is plasticized by the heat retained by the nozzle 3, softened and inserted, while still hot, into the tuyere brick 2 of the tundish 1, and both members are joined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint molding which is filled between a nozzle refractory material and a tuyere refractory material to form a joint and which can join the nozzle refractory material to the tuyere refractory material. is there.

[0002]

2. Description of the Related Art Nozzle refractories used in continuous steel casting operations include long nozzles and immersion nozzles. Immersion nozzles will be described here. That is, the immersion nozzle connects the two so as to supply molten steel from the tundish to the mold, and is attached to the tuyere of the tundish. A joint material is filled between the tuyere and the dipping nozzle in order to prevent molten steel from entering and causing accidents such as leakage of molten metal. Usually, such a joint material is composed of mortar which has been kneaded with water, and this mortar is applied to the tuyere joint portion of the dipping nozzle to a predetermined thickness by hand, and the tundish and the tundish after mounting the dipping nozzle on the tuyere. The joint is formed by preheating the immersion nozzle to a predetermined temperature. The joint joins the tundish and the dipping nozzle.

In the continuous casting operation, since the final process of solidifying molten steel into a billet between the tundish, the dipping nozzle and the mold, it is important to prevent contamination of the molten steel, and the tundish and the dipping nozzle are integrated. It is normally used as a continuous casting with 5 to 10 charges followed by the same steel type, and is then discarded together with the change of steel type. However, it is not preferable in terms of cost to discard and replace the tundish and the dipping nozzle each time the steel type is changed, and the tundish can be continuously treated by improving the lining material of the tundish and the method of removing the residual hot water and slag in the tundish. Considered for use.

[0004]

However, while the life of the tundish is about 100 charges, the life of the immersion nozzle is short and it is necessary to replace the immersion nozzle with 5 to 10 charges. From the viewpoint of energy saving and shortening of operating time, it is preferable to replace the immersion nozzle hot. However, the preheating temperature of the immersion nozzle is 70
It is impossible to apply water-mixed mortar to the immersion nozzle in the hot range of 0 to 1200 ° C, and if the normal temperature immersion nozzle coated with mortar is attached to a hot tundish, the immersion nozzle spalls, In order to join the immersion nozzle to the tundish by the above-mentioned conventional method, the tundish must be once cooled to near room temperature. Therefore, in the replacement of the immersion nozzle by the conventional joining method, loss of energy during cooling of the tundish and heating to the operating temperature again, and loss of time during that period are unavoidable, which contributes to energy saving and shortening of operating time. There is a problem of being contrary. DISCLOSURE OF THE INVENTION The present invention aims to solve the above problems, and provides a joint molding capable of inserting and joining a nozzle refractory such as an immersion nozzle into a tuyere refractory while hot. It is what

[0005]

In order to achieve the above-mentioned object, the joint molding according to the present invention is basically a refractory material; 40% of the total composition of 100 wt%. ~
90 wt% and a binder; 10 to 60 wt% and formed into a molded body having a shape corresponding to the joint between the nozzle refractory and the tuyere refractory to be joined. It is characterized in that it is attached to the upper outer peripheral portion of the nozzle refractory and exhibits plasticity due to the retained heat of the nozzle refractory.

The refractory materials used in the present invention include alumina, magnesia, silica, zirconia, zircon,
Any material that can be used as a material for mortar such as titania, bauxite, granite, wax stone, etc. may be used, and carbonaceous materials such as phosphorous graphite, earthy graphite and coke may be used in combination. Refractory materials can also be mixed and used. In general, the refractory material preferably has the same composition as the nozzle refractory and tuyere refractory to be joined. If the content of such a refractory material is less than 40 wt%, the fire resistance at the continuous casting operating temperature, the molten steel, the erosion resistance to slag, and the wear resistance decrease, and the content of the binder inevitably increases. When the joint molding is mounted so as to cover the preheated nozzle refractory, it is excessively plasticized by the retained heat of the nozzle refractory and flows down by its own weight. Also, if it exceeds 90 wt%, the amount of the binder to be blended will inevitably decrease, so the plasticization due to the retained heat of the preheated nozzle refractory is insufficient, and as a joint material when set in the tuyere refractory. Fillability deteriorates.

As the binder, a thermoplastic resin and / or pitches are mainly used. As an example of the thermoplastic resin, a thermoplastic phenol resin (novolak resin containing almost no hexamine), and as the pitches, coal pitch or petroleum High residual coal pitch with high pitch or mesophase content is desirable. Since these binders develop plasticity when heat is applied, when a nozzle refractory equipped with a joint molding containing these binders is joined to a tuyere refractory, it is plasticized by preheating the nozzle refractory. The converted joint material flows along the joint portion and is filled into the joint shape. However, these thermoplastic resins and / or pitches tend to have too much fluidity in the hot state, and when the blending amount of these thermoplastic resins and / or pitches is large, the joint molding is attached to the upper outer peripheral portion of the preheated nozzle refractory. There is a risk of fluidization immediately after.
The compounding ratio of the binder as described above is preferably 10 to 60 wt%, and particularly preferably 20 to 50 wt%, although it is somewhat dependent on the preheating temperature at the time of replacing the nozzle refractory. If it is less than 10 wt%, sufficient plasticity and fluidity cannot be obtained, making it difficult to fill it as a joint material, and if it exceeds 60 wt%, the joint material flows too quickly and flows out from the joint, resulting in the formation of joints. It will be difficult.

In order to adjust the hot fluidity of the joint material, a thermosetting resin such as a phenol resin having a high residual carbon content may be used in combination as one of the binders. In addition, this thermosetting resin has a preferable blending amount of the binder of 10 to 60 wt%.
Among them, the ratio of the thermoplastic resin and / or pitches to the thermosetting resin is 90/10 to 10/90, preferably 80
It can be used in the range of / 20 to 40/60.

It is also preferable to add 0.1 to 10 wt% of carbon fiber by external coating to 100 wt% of the total amount of the above-mentioned compounding composition, and to increase the strength as a molded product and a joint material by the effect of rustiness. .. The amount of such carbon fiber added is 0.
If it is less than 1 wt%, the effect of increasing the strength is not small, and if it exceeds 10 wt%, it becomes difficult to uniformly knead the mixture during molding.

[0010]

The joint molded body, which is molded into a shape corresponding to the joint between the nozzle refractory and the tuyere refractory to be joined, is mounted on the outer periphery of the upper portion of the nozzle refractory to be preheated. It is plasticized by the heat it retains. Next, the nozzle refractory is inserted and joined in the tuyere refractory in a plasticized state of the joint molding. Thus, the joint molded body is filled between the nozzle refractory and the tuyere refractory, and the joint molded body is in a hot-fired state and is eroded by molten steel, slag, etc. It forms a fine joint to withstand, and firmly joins the nozzle refractory to the tuyere refractory.

Since a series of steps from the setting of the joint molded body to the formation of the fine joint as described above are performed hot, for example, the tundish is cooled even when the immersion nozzle connected to the tundish is replaced. There is no need to do it, and the replacement is done promptly.

Since the joint molding of the present invention has a shape-retaining property of moderate strength at room temperature, it can be smoothly mounted on the nozzle refractory without being damaged by the handling by the robot and can be hot-worked. Easy to operate. Also,
While hot, it exhibits an appropriate degree of plasticity and smoothly fills the joint site.

[0013]

EXAMPLES Next, specific examples of the joint molding according to the present invention will be described with reference to the drawings and tables.
Alumina powder and phosphorous graphite as the refractory material, coal pitch powder and thermoplastic phenolic resin as the thermoplastic binder, thermosetting phenolic resin as the thermosetting binder, and carbon fiber materials in the mixing ratios shown in Table 1. They were used and mixed with a Henschel mixer to prepare joint materials. These joint materials are heated to 150 ° C. to impart fluidity, and as shown in FIGS. 1 and 2, correspond to joints between the tuyere brick 2 of the tundish 1 and the dipping nozzle 3, In addition, pressure molding was performed into a shape having a collar 4 on the upper portion, and after cooling and drying, a cap-shaped joint molded body 5 was obtained. In addition, in order to reliably fill the joint material, the joint molded body 5
It is desirable that the thickness of the joint be slightly thicker than the joint thickness between the tuyere brick 2 and the dipping nozzle 3 to be joined. In addition, as a comparative example, a joint molding was prepared in which the mixing ratio of each material deviates from the range of the present invention, and the mixing ratios thereof are also shown in Table 1.

[0014]

[Table 1]

The joint molding 5 produced as described above is put on the immersion nozzle 3 preheated to 1000 ° C., and the joint molding 5 is plasticized and softened by the heat retained by the immersion nozzle 3 for 2 minutes. After that, the tuyere bricks 2 of the tundish 1 were hot-inserted and attached to join them. Then, when No. 1 of the present invention was continuously cast with 5 charges, No. 2 and No. 3 were 8 charges, and No. 4 and No. 5 were 7 charges, none of them leaked. Further, when the dipping nozzle 3 was removed from the tundish 1 after the end of continuous casting and the joints were visually observed, good results were obtained without any penetration of molten steel. However, Comparative Example N
I tried to insert and join the o.6 and No.8 joint molding 5 to the tuyere brick 2 by covering it with the dipping nozzle 3, but since the joint material has low plasticity and the fluidity suitable for joining cannot be obtained. ,
Only part of the tip of the immersion nozzle 3 was inserted into the tuyere brick 2 and they could not be joined. Also,
The joint moldings 5 of Comparative Examples No. 7 and No. 9 have excessive plasticity of the jointing material, and when the joint molding 5 is covered with the dipping nozzle 3, the joint molding 5 has large fluidity and is inserted into the tuyere brick 2 before joining. The joint material couldn't be joined because it flowed down.

Since the joint molded body in this embodiment has a collar having an upper portion, when it is covered by the heat of the immersion nozzle so as to cover the top of the immersion nozzle, it is plasticized.
It has the effect of preventing slipping from the immersion nozzle. Further, since the acid prevention material applied to the surface of the dipping nozzle acts as an adhesive while hot, when the dipping nozzle is removed, the joint molding is adhered to the dipping nozzle and the tuyere brick is removed together with the dipping nozzle. To be removed. Therefore, maintenance of the tuyere brick surface is not required, and the next immersion nozzle can be quickly mounted.

[0017]

EFFECTS OF THE INVENTION Since the joint molding according to the present invention has a shape-retaining property at room temperature and is plasticized hot, it is possible to join a fixed refractory material while hot. Therefore, for example, when the joint molding according to the present invention is used in a continuous casting operation, the immersion nozzle can be exchanged hot, which contributes to energy saving and shortening of operating time.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a joint molding and a dipping nozzle according to the present invention mounted on a tundish.

FIG. 2 is an external perspective view of a joint molding according to the present invention.

[Explanation of symbols]

 1 Tundish 2 Tuyere brick 3 Immersion nozzle 4 Tsuba 5 Joint molding

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[Procedure amendment]

[Submission date] December 5, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location C04B 35/66 M 7305-4G Q 7305-4G (72) Inventor Kiyoshi Isono Hirohata-ku, Himeji City, Hyogo Prefecture Fuji Town No. 1 Shin Nippon Steel Co., Ltd. Hirohata Works (72) Inventor Yoichi Yokoyama 1-3-1, Niihama, Niihama, Arai Town, Takasago City, Hyogo Prefecture (72) Inventor Tatsuo Okada Hirohata, Himeji City, Hyogo Prefecture 1-21-2 Omachi, Tokyo Stock company Okada Shokai

Claims (4)

[Claims] 1. A nozzle refractory and a tuyere refractory, which are composed of a refractory material; 40 to 90 wt% and a binder; 10 to 60 wt% out of a total amount of 100 wt% of the composition. For joints characterized by being molded into a molded body having a shape corresponding to a joint between the nozzles and attached to the upper outer peripheral portion of the nozzle refractory during replacement of the nozzle refractory to exhibit plasticity due to the heat retained by the nozzle refractory. Molded body. 2. The joint molding according to claim 1, wherein the binder is a thermoplastic resin and / or a pitch. 3. The joint molding according to claim 1, wherein the binder is a thermosetting resin, a thermoplastic resin, and / or pitches. 4. The total amount of the composition is 100 wt%,
The molded joint product according to any one of claims 1 to 3, wherein 0.1 to 10 wt% of carbon fiber is added to the outside.