JP2684501B2 - Casting method for irregular refractories - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for constructing a cast refractory material having a raised portion.

[0002]

2. Description of the Related Art The hot water contact portion of a ladle with a flat plate shape receives the molten steel from the converter according to the molten steel drop distance.
Due to the large impact and wear action, the wear rate is 2 to 4 times higher than other parts. For this reason, it is usual that the hot water contact portion has a larger thickness of refractory lining than the other portions. For this reason, it has been customary in the past to perform an indeterminate pouring construction of the ladle floor portion by installing a previously formed hot water contact block at a predetermined position and then surrounding the block.

In the case of casting a ladle sill on the entire surface in an irregular shape, the method of increasing the thickness of the refractory lining in the hot water contact part (hereinafter referred to as the raised part) is to prepare a large frame corresponding to the entire surface of the slab. However, it is necessary to set the horizontal level of the frame and take levitating measures, which is inefficient and requires a large space for storing the frame.

As an alternative method, a prefabricated hot water contact block 5 as shown in FIG. 9 is installed at a predetermined position and poured into the other parts 1 and 2 of the floor 8 in general. Although it is used, joints are formed between the block and the pouring material, molten steel enters into these joints, and if left unattended, there will be a molten metal leak accident, so the frequency of replacement is increased. Therefore, there are drawbacks such as high replacement cost and high pre-production cost.

It is an object of the present invention to provide a method for constructing a refractory material which has a raised portion and which is poured into a ladle having a flat plate shape and the like.

[0006]

According to the present invention, in a casting method for casting an irregular-shaped refractory, a construction area to be partially raised is divided into a raised peripheral portion, a raised lower portion, and a raised portion, and the formwork is raised around the raised portion. By appropriately using the boundary between the part and the raised part and the raised part, the irregular shaped refractory is poured in the order of (1) raised part (2) raised part (3) raised part, and the raised part and raised part, and The time interval for the refractory material to flow between the lower part of the raised area and the raised area should be within the time when the adhesive strength between the two parts is greater than the specified value after drying. Is a method of pouring the irregular shaped refractory, which is characterized by a hardening time that does not deform.
The construction order is as follows. (1) A formwork set for a boundary between a raised peripheral portion and a raised lower portion. (2) Pouring of irregular-shaped refractory into the raised peripheral area. (3) Pouring of irregularly shaped refractory into the lower part of the raised pad. (4) Removing the formwork of (1) above (5) Setting a frame for raising a building (6) Pouring an indeterminate refractory material into the raising section.

[0007]

The operation of the present invention will be described with reference to the alumina spinel refractory material shown in Table 1 as an example. The refractory material flow-in time intervals for making the adhesive strength after drying of the raised portion and the raised portion and between the raised portion and the raised portion not less than a predetermined value were determined by the test method shown in FIG. That is, the casting material A is applied to the frame, and B is applied later. 110
After drying at 24 ° C. for 24 hours, a load is applied to the boundary between A and B to perform a bending strength test. The results are shown in Fig. 2. The casting material A
The interval between B and B is 30 kg, which is the standard of bending strength.
In order to secure a value of / cm ² or more, it should be within 25 minutes.

[0008]

[Table 1]

Further, it is important that the pouring materials A and B are well mixed at the boundary as to the adhesiveness at the boundary between the two.
In the tap flow test shown in Fig. 2, the working interval time during which both can be stirred was investigated. D = 80 mm, X is the diameter of the casting material after being subjected to vibration for the interval time. The results are shown in FIG. 4, and the interval time between constructions in which both can be stirred is within 20 minutes.

From the above results, if the refractory material flow-in time interval of each part is within 20 minutes, the adhesive strength at the boundary between the two parts becomes a predetermined value or more.

The refractory material flow-in time interval between the raised portion and the raised portion is optimal at the time when the raised portion does not deform due to the weight of the raised portion, that is, when the fluidity decreases.

Although the fluidity of the casting material can be known by the tap flow test shown in FIG. 3, the inventors' research shows that the fluidity of the casting material decreases when the tap flow value is 110 as shown in FIG. Is. From this, the deformation of the raised portion can be prevented by applying the upper portion of the raised portion 30 minutes or more after the completion of the work of the raised portion.

[0013]

EXAMPLES Examples of the present invention and comparative examples will be described below.
Based on the experimental results shown above, pouring was carried out on the ladle floor in the process shown in FIG. The frame 6 is set on the lower portion (hot water contact portion) of the raised pad, and the casting material a is applied to the peripheral portion of the raised pad. After that, the raised lower part (hot water contact part) b is constructed, the frame 6 is removed, and the boundary between a and b is mixed with a vibrator. After that, c is applied to the raised portion (hot water contact portion) 4 with the raised frame 7 attached, and the boundary between b and c is mixed with a vibrator.

As shown in FIG. 7, the time cycle of each step is such that the refractory material inflow interval time between the raised peripheral portion a and the raised lower portion b and between the raised lower portion b and the raised portion c can maintain the adhesiveness at the boundary between them. It will be installed within 20 minutes. Further, since the refractory material flow-in interval time of the raised portion c and the raised peripheral portion a is secured for 30 minutes or more, the raised peripheral portion is not deformed by the weight of the raised portion c.

The present invention can also be used for hot water on a ladle floor as shown in FIG. 8 and hot water for a continuous casting tundish.

[0016]

As described above, the entire surface cast refractory work body of the present invention can be inexpensively bulked up and has a long service life. The ladle embodying the present invention has few repairs in the hot water contact portion and does not require an expensive block, and thus has the effect of realizing a significant cost reduction over the conventional method shown in FIG.

[Brief description of the drawings]

FIG. 1 shows a method of bending a cast material.

FIG. 2 also shows the bending test results of the cast material.

FIG. 3 shows a tap flow test method for a casting material.

FIG. 4 shows a result of tap flow test of a cast material.

FIG. 5 shows a method for pouring a ladle floor as an embodiment of the present invention.

FIG. 6 is a schematic view of a flat plate-like cast product having a raised portion.

FIG. 7 shows a pouring construction time cycle according to the embodiment of the present invention.

FIG. 8 is a sectional view of a ladle as an embodiment of the present invention.

FIG. 9 is a cross-sectional view of a conventional method for pouring ladle.

[Explanation of symbols]

 1 Ladle 2 Wall pouring material 3 Laying pouring material 4 Raised part (hot water contact part) 5 Hot water block 6 Frame for pouring material at the lower part of the raising part 7 Frame for pouring material of the raising part a Pouring material c pouring material of raised part

Claims (1)

(57) [Claims] 1. A method for pouring an irregularly shaped refractory material for partially raising a building, wherein the working area is divided into a raising peripheral portion, a raising lower portion and a raising portion, and a formwork is formed in the raising peripheral portion and the raising lower portion. By using as appropriate for the boundary and the raised part, (1) raised part, (2) raised part, (3) raised part, in addition to pouring indefinite refractory material, the raised part and raised part, and raised part and raised part The time interval for refractory physical distribution between the two parts is within a time period in which the adhesive strength between the two parts becomes greater than a predetermined value after drying, and the time interval for refractory physical distribution between the raised part and the raised part is such that the raised part does not deform due to the weight of the raised part. A method for pouring in an irregular shaped refractory, which is characterized in that it takes more than an hour.