JP2644404B2 - Joint molding - Google Patents

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 and a tuyere refractory to form a joint, and the nozzle refractory can be joined to the tuyere refractory. is there.

[0002]

2. Description of the Related Art As nozzle refractories used in continuous casting operation of steel, there are a long nozzle and a submerged nozzle. Here, the submerged nozzle will be described. That is, the immersion nozzle connects the two in order to supply molten steel from the tundish to the mold, and is mounted on the tuyere of the tundish. A joint material is filled between the tuyere and the immersion nozzle in order to prevent molten steel from entering and preventing accidents such as hot water leakage. Usually, such a joint material is made of water-mixed mortar, and the mortar is applied to the tuyere joint of the immersion nozzle by hand or the like to a predetermined thickness, and after attaching the immersion nozzle to the tuyere, a tundish and The joint is formed by preheating the immersion nozzle to a predetermined temperature. The joint connects the tundish and the immersion nozzle.

[0003] In the continuous casting operation, it is important to prevent the molten steel from being contaminated since the molten steel is solidified into a slab from the tundish to the immersion nozzle to the mold in the final process. After the continuous casting of 5 to 10 charges, usually followed by the same steel type, is discarded with the change of the steel type. However, discarding and replacing the tundish and the immersion nozzle each time the steel type is changed is not preferable in terms of cost.Consequently, the tundish is continuously replaced by improving the lining material of the tundish or improving the method of removing residual hot water and slag in the tundish. Use is being considered.

[0004]

However, while the life of the tundish is about 100 charges, the life of the immersion nozzle is short, and the immersion nozzle needs to be replaced every 5 to 10 charges. The replacement of the immersion nozzle is preferably performed hot from the viewpoint of energy saving and shortening of operation time. However, the preheating temperature of the immersion nozzle, 70
It is impossible to apply water-mixed mortar to the immersion nozzle at a temperature of 0 to 1200 ° C, and when the mortar-coated normal temperature immersion nozzle is mounted on a hot tundish, the immersion nozzle spalls. In order to join the immersion nozzle to the tundish by the conventional method described above, the tundish must be once cooled to near normal temperature. Therefore, in the replacement of the immersion nozzle by the conventional joining method, energy loss while cooling the tundish and heating it again to the operating temperature, and the time loss during that time are inevitable, saving energy and shortening operation time. There is a problem that it goes against. An object of the present invention is to provide a molded article for joints in which a nozzle refractory such as an immersion nozzle can be inserted into and joined to a tuyere refractory in a hot state in order to solve such a problem. It is assumed that.

[0005]

In order to achieve the above-mentioned object, a joint molding according to the present invention has a total composition of 1%.
Of the 00 wt%, a refractory material; 40 to 90 wt%, and a binder composed of a thermosetting resin and a thermoplastic resin and / or pitches; It is molded into a molded product having a shape corresponding to the joint between the tuyere refractory and is attached to the upper outer peripheral portion of the nozzle refractory when exchanging the nozzle refractory, and exhibits plasticity due to the retained heat of the nozzle refractory. It is characterized by the following.

The refractory materials used in the present invention include alumina, magnesia, silica, zirconia, zircon,
Any material such as titania, bauxite, shale, and mortar may be used as long as it can be used as a material for mortar, and carbonaceous materials such as phosphorous graphite, earthy graphite, and coke may be used in combination. A mixture of refractory materials can also be used. Generally, 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% by weight, the fire resistance at the continuous casting operation temperature and the corrosion resistance to molten steel and slag and the wear resistance are reduced, and the content of the binder is inevitably increased. When the joint forming body is mounted so as to cover the preheated nozzle refractory, there is a problem that the plastic is excessively plasticized by the retained heat of the nozzle refractory and flows down by its own weight. On the other hand, if the content exceeds 90 wt%, the amount of the binder is inevitably reduced. The filling property deteriorates.

As the binder, a thermoplastic resin and / or pitches are mainly used. As an example of the thermoplastic resin, a thermoplastic phenol resin (a novolak resin containing almost no hexamine) is used. High resid coal pitch with high pitch or mesophase content is desirable. Since these binders exhibit plasticity when heat is applied, when a nozzle refractory equipped with a joint forming body containing these binders is joined to a tuyere refractory, the nozzle refractory is plasticized by preheating. 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 excessive hot fluidity. If the blending amount of these thermoplastic resins and / or pitches increases, the joint molding is mounted on the upper outer peripheral portion of the preheated nozzle refractory. May flow immediately after
The mixing ratio of the binder as described above slightly depends on the preheating temperature at the time of exchanging the refractory of the nozzle, but is preferably from 10 to 60% by weight, particularly preferably from 20 to 50% by weight. If the content is less than 10 wt%, sufficient plasticity and fluidity cannot be obtained, so that it is difficult to fill as a joint material. If the content is more than 60 wt%, the joint material flows too fast and flows out of the joint to form the joint. It will be difficult.

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

It is also preferable to add 0.1 to 10% by weight of carbon fiber on the outside with respect to the total amount of 100% by weight of the above composition. . 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 composition during molding.

[0010]

The joint molding formed into a shape corresponding to the joint between the nozzle refractory and the tuyere refractory to be joined is mounted on the upper outer peripheral portion of the preheated nozzle refractory, and the nozzle refractory is provided. It is plasticized by the heat of the material. Next, in a state where the joint molding is plasticized, the nozzle refractory is inserted and joined in the tuyere refractory. In this way, the joint forming body is filled between the nozzle refractory and the tuyere refractory, and the joint forming body is baked hot to erode and wear the molten steel and slag. To form a dense joint that can withstand the refractory, and to firmly join the nozzle refractory to the tuyere refractory.

[0011] Since a series of steps from the setting of the joint forming body to the formation of the dense joint as described above are performed by heating, the tundish is cooled even when the immersion nozzle connected to the tundish is replaced, for example. There is no need to do this, and the exchange is performed promptly.

The molded article for joints according to the present invention has a moderately strong shape-retaining property at room temperature, so that it can be smoothly mounted on the nozzle refractory without being broken even by handling by a robot, so that it can be heated during heating. Operation is easy. Also,
When hot, it exhibits moderate plasticity and fills the joint site smoothly.

[0013]

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 a refractory material, coal pitch powder and a thermoplastic phenolic resin as a thermoplastic binder, a thermosetting phenolic resin as a thermosetting binder, and carbon fiber were mixed in the proportions shown in Table 1. Each was mixed with a Henschel mixer to prepare a joint material. By heating these joint materials to 150 ° C. to impart fluidity, they correspond to the joints between the tuyere brick 2 of the tundish 1 and the immersion nozzle 3 as shown in FIGS. Further, it was press-molded into a shape having a flange 4 on an upper portion, and after cooling and drying, a cap-shaped joint-formed body 5 was obtained. In order to ensure the filling of the joint material, the joint molding 5
Is desirably slightly thicker than the joint between the tuyere brick 2 and the immersion nozzle 3 to be joined. As comparative examples, joint moldings in which the mixing ratio of each material is out of the range of the present invention were prepared, and the mixing ratios are shown in Table 1.

[0014]

[Table 1]

The joint molding 5 prepared as described above is placed on the immersion nozzle 3 preheated to 1000 ° C., and the joint molding 5 exhibits plasticity and softness due to the heat retained by the immersion nozzle 3 for 2 minutes. Later, hot tundish 1
The tuyere bricks of No. 2 were inserted and mounted to join them. Then, the present invention example No. 1 and No. 2 is 8 charges,
No. 3 and No. 3 As for No. 4, when the continuous casting of 7 charges was performed, none of the hot water leaked. After the end of the continuous casting, the immersion nozzle 3 was removed from the tundish 1, and the joints were visually observed. As a result, good results were obtained without any penetration of molten steel. However, Comparative Example N
o. 5 and No. 5 7 is immersed in nozzle 3
The tuyere brick 2 was inserted into the tuyere brick 2, but the plasticity of the joint material was so small that fluidity suitable for joining could not be obtained. Therefore, a part of the tip of the immersion nozzle 3 was inserted into the tuyere brick 2. They were not able to be joined together.
Also, in Comparative Example No. 6 and no. Joint molding 5 of 8
Since the plasticity of the joint material was excessive, the joint material 5 was covered with the immersion nozzle 3, the flowability was large, and the joint material flowed down before insertion and joining to the tuyere brick 2, and the joint materials could not be joined. .

Since the joint forming body in the present embodiment has a shape having a flange on the upper part, when the plastic is formed by covering heat so as to cover the top of the immersion nozzle,
This has the effect of preventing slippage from the immersion nozzle. In addition, since the acid inhibitor applied to the surface of the immersion nozzle acts as an adhesive hot, when removing the immersion nozzle, the joint molding is adhered to the immersion nozzle and the tuyere brick is removed together with the immersion nozzle. Removed. Therefore, maintenance of the tuyere brick surface is unnecessary, and the next immersion nozzle can be quickly mounted.

[0017]

The molded article for joints according to the present invention has shape-retaining properties at room temperature and plasticizes when hot, so that a fixed refractory can be joined hot. Therefore, for example, if the joint forming body 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 operation time.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a joint forming body 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]

 DESCRIPTION OF SYMBOLS 1 Tundish 2 Tuyere brick 3 Immersion nozzle 4 Flange 5 Joint molding

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication C04B 35/66 C04B 35/66 M Q (72) Inventor Yoichi Yokoyama 1-chome, Araimachi, Takasago City, Hyogo Prefecture No. 3-1 Harima Ceramics Co., Ltd. (72) Inventor Tatsuo Okada 1-21-2 Omachi, Hirohata-ku, Himeji-shi, Hyogo Prefecture Examiner, Okada Shokai Co., Ltd. Michichi Chino (56) References JP-A-3-221248 ( JP, A) JP 1-20943 (JP, B2) JP 61-14111 (JP, B2) JP 1 33259 (JP, Y2)

Claims (2)

(57) [Claims] 1. A refractory material of 40% to 90% by weight of a total of 100% by weight of a compounding composition, and a thermosetting resin and a thermosetting resin.
A binder comprising a plastic resin and / or pitches ; 1
0 to 60 wt%, and is formed into a molded body having a shape corresponding to the joint between the nozzle refractory and the tuyere refractory to be joined, and the upper outer periphery of the nozzle refractory when the nozzle refractory is replaced. A molded article for joints, which is attached to a portion and exhibits plasticity by heat retained by the nozzle refractory. 2. The joint molding according to claim 1 , wherein 0.1 to 10% by weight of carbon fiber is externally added to the total amount of 100% by weight of the composition.