WO2019171895A1

WO2019171895A1 - Tuyere setting structure

Info

Publication number: WO2019171895A1
Application number: PCT/JP2019/005130
Authority: WO
Inventors: 幸司瓦田
Original assignee: 黒崎播磨株式会社
Priority date: 2018-03-06
Filing date: 2019-02-13
Publication date: 2019-09-12
Also published as: JP2019150863A; TW201938291A

Abstract

The present invention provides a tuyere setting structure in which no gap is generated between a nozzle or plug set at the bottom of a molten metal container and a plate or the like located below the nozzle or plug, and between the nozzle or plug and a tuyere located above or on the outer peripheral side of the nozzle or plug. In the tuyere setting structure according to the present invention, a tuyere 2 which is set so as to surround a plug or a nozzle 1 for discharging molten metal downwardly from the bottom of the molten metal container, is fixed, with studs 3, to an iron shell 4 at the bottom of the molten metal container.

Description

Installation structure of tuyere

The present invention relates to a tuyere installation structure installed so as to surround a nozzle or a plug for discharging molten metal downward from the bottom of a molten metal container.

In order to discharge the molten metal downward from the bottom of the molten metal container, the nozzle installed at the bottom of the molten metal container includes a plate-like sliding nozzle device, an immersion nozzle, and an upper nozzle for controlling the flow rate of the molten metal. Etc.

For example, the upper plate for the sliding nozzle device is fixed to the iron shell at the bottom of the molten metal container, and the upper nozzle installed on the upper plate is a part of the refractory layer inside the iron plate at the bottom of the molten metal container. Between the tuyere and the tuyere that is in direct contact with the upper nozzle.
The boundary between the lower end of the upper nozzle and the upper plate in such an installation structure is considered to be a structure with a certain thickness in close contact, but during use, the joint part is separated and the interval is increased. There may be voids.
Further, even at the boundary between the upper nozzle and the tuyere, the joint portion of the boundary portion may be separated and the interval may be increased, resulting in a gap.
When such voids are generated, molten metal may enter the voids, which may cause a molten metal leakage accident.

In order to suppress the formation of voids at the boundary between the upper nozzle and the upper plate or tuyere, it has been attempted to take measures mainly for the upper nozzle.
For example, Patent Document 1 states that “the outer peripheral surface taper angle of the hollow frustoconical upper nozzle is less than 7 °, and a molten metal holding container such as a tundish or a ladle is placed on the outer periphery of the upper nozzle located immediately above the sliding gate. An upper nozzle for a sliding gate provided with a positioning projection for hanging on a lower outer wall or a refractory is disclosed (see the abstract of Patent Document 1).
Patent Document 2 states that “the upper nozzle 20 has a frustoconical shape and the lower part has a cylindrical shape, and has a nozzle hole through which molten metal passes in the axial center, and the upper nozzle provided at the bottom of the molten metal container. In a casting nozzle structure in which a nozzle receiving brick 20 is inserted from below and a sliding flow control device (slide valve) 4 is disposed below the upper nozzle, the lower end of the upper nozzle 20 "A casting nozzle structure in which concave portions 21 and / or convex portions 24 are formed on the outer peripheral surface excluding" is disclosed (see abstract of Patent Document 2).

A plug installed inside the tuyere for the purpose of blowing gas into the molten metal container or energizing may cause a gap between the tuyere and the iron skin in the same manner as the upper nozzle described above. There is a high risk of causing an accident.

Japanese Patent Laid-Open No. 11-207457 JP 2002-35926 A

In Patent Literature 1, the upper nozzle itself is restrained from moving upward with respect to the iron skin or the like of the molten metal container by the “positioning protrusion that is latched to the lower outer wall of the molten metal holding container or the refractory”. be able to. However, the upper nozzle is not fixed to the tuyere and does not have a function to fix the tuyere, so when the tuyere moves upward, the upper nozzle moves relative to the tuyere. It becomes possible, and void formation between them is inevitable.

The mechanism of the void formation will be described with reference to FIG.
As shown in the figure, in the conventional tuyere installation structure, the tuyere 2 is not directly fixed to the iron skin 4 at the bottom of the molten metal container. When the refractory lining layer at the bottom of the molten metal container including the tuyere 2 moves from the iron skin 4 at the bottom of the molten metal container to the inside of the molten metal container, that is, upward, due to heat or other causes, the tuyere 2 is linked to it. Thus, it moves easily in the inner direction (upward direction) of the molten metal container, and a gap 9 is formed between the bottom of the molten metal container and the iron skin 4.
On the other hand, the upper nozzle 1 can move between the lower structure 7 (here, the upper plate is taken as an example). That is, the upper nozzle 1 has a larger contact area with the tuyere 2 than a contact area with the lower component 7 (area of the joint), and a slag or scale is formed on the upper nozzle 1 above the tuyere 2. Often infiltrates or reacts with the surface to produce a tightly integrated part. For these reasons, the upper nozzle 1 moves upward so as to move away from the lower component 7 and interlock with the tuyere 2, and a gap 6 is formed between the upper nozzle 1 and the lower component 7.
As another method, the present inventors applied a structure in which the upper nozzle is locked to a lower sliding nozzle device located outside the iron skin with metal parts. However, in this case, the upper nozzle rises together with the tuyere and the metal part is deformed, or the vicinity of the metal part of the upper nozzle is broken to prevent the generation of a gap between the upper nozzle and the upper plate. I couldn't.

In Patent Document 2, the upper nozzle does not move relative to the mortar by the concave portion or the convex portion provided on the outer peripheral surface excluding the lower end of the upper nozzle, and the convex portion is provided with the convex portion of the tuyere. If it is the form which bites into an inner surface, it can suppress that an upper nozzle moves upwards with respect to a tuyere. However, as described in Patent Document 1 and FIG. 5 described above, Patent Document 2 does not have a function of fixing the tuyere, so when the tuyere itself moves upward, the upper nozzle is interlocked with the tuyere. Therefore, it is inevitable to form a gap with the plate located below the upper nozzle.

The phenomenon as described above may occur not only in the nozzle but also in a plug installed inside the tuyere for the purpose of gas blowing or for energization.

The problems to be solved by the present invention are located between a nozzle or plug installed at the bottom of a molten metal container and a plate or the like located below the nozzle or plug, and above or outside the nozzle or plug. It is to provide a tuyere installation structure that does not generate a gap between the tuyere.
By doing so, it is intended to prevent the occurrence of air entrainment from the air gap and leakage of molten metal.

According to the present invention, the tuyere installation structure described in the following 1 to 4 is provided.
1. A tuyere installation structure installed so as to surround a nozzle or plug for discharging molten metal downward from the bottom of the molten metal container, and the tuyere is fixed to the iron skin at the bottom of the molten metal container by a stud The tuyere installation structure.
2. The tuyere is composed of an inner hole side refractory layer and an outer peripheral side refractory layer in the radial direction from the inner hole central axis,
At least one of the inner hole side refractory layer and the outer peripheral side refractory layer is fixed to the iron skin at the bottom of the molten metal container by a stud;
An upward movement blocking portion for preventing upward movement of the inner hole side refractory layer with respect to the outer peripheral side refractory layer at a contact portion between the inner hole side refractory layer and the outer peripheral side refractory layer The tuyere installation structure according to 1 above, comprising:
3. The tuyere installation structure according to 2, wherein at least one of the inner hole side refractory layer or the outer periphery side refractory layer is an amorphous refractory.
4. The tuyere installation structure according to 2 or 3 above, wherein the coefficient of thermal expansion up to 1500 ° C. has a relationship of the inner hole side refractory layer ≧ the outer periphery side refractory layer at the same temperature.

According to the present invention, the tuyere installed inside the molten metal container bottom iron shell is fixed to the molten metal container bottom iron core by the stud, so the tuyere moves upward (in the molten metal container inner direction). There is nothing. As a result, the nozzle or plug, such as the upper nozzle, installed on the inner hole side of the tuyere does not move upward relative to the tuyere, and is It does not move in the direction. As a result, it is possible to prevent the generation of a gap between them, or to prevent air entrainment in the nozzle bore or leakage of molten metal.
As shown in 2 of the present invention, the tuyere is composed of two separable parts, ie, the inner hole side refractory layer and the outer periphery side refractory layer, and the inner hole side refractory layer and the outer periphery side refractory The inner hole side refractory layer portion is provided on the outer peripheral side by providing an upward movement blocking portion for suppressing upward movement of the inner hole side refractory layer relative to the outer peripheral side refractory layer at the contact portion with the layer. The structure fixed to the refractory layer portion can be maintained.
Furthermore, in the form composed of these two separable parts, it is easy to replace them individually depending on the damage form and the degree of damage, and the cost of the material is maintained while maintaining the fixed structure of the tuyere. It is possible to reduce the labor and cost for reduction and repair work. In particular, at least one of these is made into an indeterminate refractory that can be installed in the field, making these replacements and repairs even easier.
As shown in 4 of the present invention, in the form in which the coefficient of thermal expansion up to 1500 ° C. is in the relationship of the inner hole side refractory layer ≧ the outer periphery side refractory layer, voids or looseness may occur between them. It is further suppressed and the fixation of these tuyere can be strengthened.

The image figure of the longitudinal direction cross section which shows the installation structure of the tuyere which is the 1st Embodiment of this invention. The image figure of the longitudinal direction cross section which shows the installation structure of the tuyere which is the 2nd Embodiment of this invention. The image figure of the longitudinal cross-section which shows the installation structure of the tuyere which is the 3rd Embodiment of this invention. The image figure of the longitudinal cross-section which shows the installation structure of the tuyere which is the 3rd Embodiment of this invention. The image figure of the longitudinal direction cross section which shows the example of the installation structure of the conventional tuyere.

FIG. 1 is an image view of a longitudinal section showing a tuyere installation structure according to the first embodiment of the present invention. In this embodiment, the tuyere 2 is composed of a single layer, and is fixed to the iron skin 4 by a stud 3 that is installed on the iron skin 4 at the bottom of the molten metal container and extends inside the tuyere 2.

FIG. 2 is an image view of a longitudinal section showing the tuyere installation structure according to the second embodiment of the present invention. In this embodiment, the tuyere 2 is composed of two layers of an inner hole side refractory layer 2a and an outer periphery side refractory layer 2b, and is installed on the iron shell 4 at the bottom of the molten metal container and extends into the outer periphery side refractory layer 2b. The stud 3 is fixed to the iron skin 4. In addition, in the contact portion between the inner hole side refractory layer 2a and the outer peripheral side refractory layer 2b, the upward movement prevention is performed to prevent the inner hole side refractory layer 2a from moving upward relative to the outer peripheral side refractory layer 2b. As a part, the taper fitting part 2c which diameter-expands toward the downward direction is provided.

FIG. 3 is an image view of a longitudinal section showing the tuyere installation structure according to the third embodiment of the present invention. In this embodiment, the tuyere 2 is composed of two layers of an inner hole side refractory layer 2a and an outer periphery side refractory layer 2b, and is installed on the iron shell 4 at the bottom of the molten metal container to be inside the inner hole side refractory layer 2a. It is fixed to the iron skin 4 with an extended stud 3. In addition, in the contact portion between the inner hole side refractory layer 2a and the outer peripheral side refractory layer 2b, the upward movement prevention is performed to prevent the inner hole side refractory layer 2a from moving upward relative to the outer peripheral side refractory layer 2b. As a part, the taper fitting part 2c which diameter-expands toward the downward direction is provided.

FIG. 4 is an image view of a longitudinal section showing a tuyere installation structure according to a fourth embodiment of the present invention. In this embodiment, the tuyere 2 is composed of two layers of an inner hole side refractory layer 2a and an outer periphery side refractory layer 2b, and is installed on the iron shell 4 at the bottom of the molten metal container and extends into the outer periphery side refractory layer 2b. The stud 3 is fixed to the iron skin 4. In addition, in the contact portion between the inner hole side refractory layer 2a and the outer peripheral side refractory layer 2b, the upward movement prevention is performed to prevent the inner hole side refractory layer 2a from moving upward relative to the outer peripheral side refractory layer 2b. As a part, it has the coating | coated part 2d which the outer peripheral side refractory layer 2b covers and contacts the upper end part of the inner-hole side refractory layer 2a.

Thus, in each embodiment, the tuyere 2 is fixed to the iron skin 4 with the stud 3 installed so as to be fixed to the iron skin 4 at the bottom of the molten metal container and extending inside the tuyere 2. In order to allow the stud 3 to exist inside the tuyere 2 in this way, a space corresponding to the size and shape of the tuyere is provided in the refractory lining at the bottom of the molten metal container at the position of the tuyere. , Studs can be installed in the space in advance, and refractories can be installed there. As the refractory serving as the tuyere, it is preferable from the viewpoint of work quality and tuyere quality to select an irregular refractory such as pouring, thrusting and blowing.

The tuyere may be a single layer or two layers. The tuyere has erosion due to slag and oxygen cleaning, wear due to molten metal, reaction with joint materials such as mortar installed between other refractories such as the upper nozzle, and damage due to the removal work. The extent of these damages depends on the tuyere site. In order to protect the molten metal container from accidents such as tuyere damage or leakage of molten metal, or to adjust the life of each part, the optimum or minimum for each damaged part against damage that varies depending on such parts. Repairs and replacements may be performed as appropriate. In order to cope with such repair and replacement, the tuyere can be made into two layers. In the case of two layers, (1) two layers in the radial direction with respect to the longitudinal central axis of the tuyere, (2) based on the above two-layer structure, and further the upper part of the inner hole side refractory layer It is possible to cover with an outer refractory layer.

In the case of these two-layer structures, in order not to move the nozzle upward, it is necessary to fix at least the inner-hole-side refractory layer so as not to move upward. The fixing part by the stud for fixing can be either one or both of the inner hole side refractory layer and the outer peripheral side refractory layer. These layers can be integrated with a refractory having an adhesive function such as mortar, or both can be integrated by direct contact. In the latter case, it is possible to fix the two layers by the adhesive force by making one side into a pre-formed shaped product and making the other into an indeterminate refractory and making direct contact.

Here, especially when the outer periphery side refractory layer is fixed with a stud and the inner hole side refractory layer is not fixed with a stud, it is not sufficient to bond these layers alone, and the inner hole side refractory layer moves upward. there's a possibility that. In view of this, the contact portion between the inner hole side refractory layer and the outer periphery side refractory layer is provided with an upward movement blocking portion for suppressing upward movement of the inner hole side refractory layer relative to the outer periphery side refractory layer. It is preferable. This upward movement blocking portion prevents the inner hole side refractory layer from moving upward relative to the outer peripheral side refractory layer in terms of geometric or mechanical structure.
As the upward movement blocking portion, in addition to the tapered fitting portion 2c and the covering portion 2d, a lateral uneven portion or a stepped portion is provided at a part of any position in the range from the upper end to the lower end. It can be configured.

In addition, such an upward movement blocking portion is not limited to preventing the inner hole side refractory layer from moving upward relative to the outer peripheral side refractory layer, but when the molten metal passes through the nozzle inner hole. When the temperature of the inner hole side refractory layer is higher than the temperature of the outer periphery side refractory layer, and both have the same thermal expansion characteristics, the inner hole side refractory layer is The contact surface can be crimped by expanding to the physical layer side.
In order to enhance this function, in the case of nozzles, the material of each refractory is selected so that the coefficient of thermal expansion up to 1500 ° C has the relationship of the inner hole side refractory layer ≥ outer periphery side refractory layer at the same temperature. More preferably. In order to configure the thermal expansion characteristics to be different, for example, a method such as changing the alumina content or changing the content ratio of minerals having different expansibility can be adopted.
In the case of a gas blowing plug, since the inner hole side of the plug is cooled by the passage of gas, the thermal expansion coefficient of the inner hole side refractory layer is higher than that of the nozzle described above. It is preferable that the relationship be higher than the thermal expansion coefficient of the outer peripheral refractory layer.

1 Upper nozzle 2 Tuyere 2a Inner hole side refractory layer (part of tuyere)
2b Outer refractory layer (part of tuyere)
2c Taper fitting part (upward movement prevention part)
2d coating part (upward movement prevention part)
3 Stud 4 Iron core of molten metal container 5 Joint between upper nozzle and tuyere 6 Joint between gap between upper nozzle and component (upper plate)
6S Thickness when gap is generated in 6 7 Upper plate (component below the upper nozzle)
8 Inner hole 9 Gaps formed between the tuyere and the iron shell at the bottom of the molten metal container 9S Thickness of 9

Claims

A tuyere installation structure installed so as to surround a nozzle or plug for discharging molten metal downward from the bottom of the molten metal container, and the tuyere is fixed to the iron skin at the bottom of the molten metal container by a stud The tuyere installation structure.
The tuyere is composed of an inner hole side refractory layer and an outer peripheral side refractory layer in the radial direction from the inner hole central axis,
At least one of the inner hole side refractory layer and the outer peripheral side refractory layer is fixed to the iron skin at the bottom of the molten metal container by a stud;
An upward movement blocking portion for preventing upward movement of the inner hole side refractory layer with respect to the outer peripheral side refractory layer at a contact portion between the inner hole side refractory layer and the outer peripheral side refractory layer The tuyere installation structure according to claim 1, comprising:
The tuyere installation structure according to claim 2, wherein at least one of the inner hole side refractory layer or the outer periphery side refractory layer is an amorphous refractory.
4. The tuyere installation structure according to claim 2, wherein a thermal expansion coefficient up to 1500 ° C. has a relationship of the inner hole side refractory layer ≧ the outer periphery side refractory layer at the same temperature.