JPH0644511Y2 - Porous plug - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is directed to temperature control and uniformization of molten steel in the steelmaking process
The present invention relates to a porous plug for gas bubbling attached to a molten metal container for stirring for refining, removal of non-metallic inclusions, and the like.

[Prior Art] A porous plug used for such an application is instantly heated from normal temperature to high temperature by molten metal and is subjected to the pressure of the molten metal. However, since the material itself forming the porous plug has a larger pore diameter than that of general refractory bricks, it is easily melted and requires frequent replacement.

It is extremely important to accurately check the amount of erosion and know the exact timing of replacement.If it is too late, it may lead to a molten metal leak accident, which is dangerous, and if it is replaced too early, The number of replacements also increases and the cost increases.

In order to easily know the timing of this replacement, a porous plug having a structure that makes it easy to confirm the melt damage state is disclosed, for example, in Japanese Utility Model Publication No. 61-4436, Japanese Utility Model Publication No. 62-8920, and Japanese Utility Model Publication No. 63-25240. Various publications are disclosed in Japanese Utility Model Publication No. Sho 63-56962.

FIG. 7 shows a typical structure of these porous plugs,
FIG. 8 and FIG. 7 show the shape of the horizontal cross section as seen from the line XIV-XIV.

In these figures, inside a dense refractory 3 arranged in a metal case 2 connected to a gas blowing pipe 1, an upper breathable refractory 4 and a lower breathable refractory 4 each having a different cross-sectional shape. No. 5, which is an upper and lower two-stage structure, and is a breathable refractory that is cooled by the flow of an inert gas during cleaning with an oxygen burner for removing the metal after discharging the molten metal from the container. The part becomes black, and the dense refractory surrounding it retains the red heat state, and the degree of melting loss is judged by visual inspection of this state.

Generally, the amount of melting loss of the porous plug is usually confirmed by hot work, so the confirmation part must be easily visible at a place far from the installation position.

However, in terms of ventilation performance, it is necessary for the porous plug to have a large contact area between the bottom surface of the upper-stage breathable refractory material 4 and the upper surface of the lower-stage breathable refractory material 5. Therefore, the cross-sectional area at the joint surface of both refractory materials is required. If the ratio is small, it will not be rough. Therefore, it is difficult to visually confirm that the level difference between the upper and lower breathable refractories at the time of melting damage is small, and even if the melting damage state due to the change in horizontal cross-sectional shape is judged, the judgment is considerable. Requires skill.

Further, in Japanese Utility Model Laid-Open No. 63-81847, there is one in which a space portion is provided in a porous plug and this is used as an object for identifying a melt-damaged state.

In this case, the molten metal penetrates into the space and solidifies, and the difference in light and dark is not clear, and it becomes difficult to identify the melted portion.

[Problems to be solved by the device]

The problem to be solved in the present invention is to clarify the replacement timing due to melting loss in a porous plug composed of a dense refractory and a breathable refractory surrounded by the dense refractory without requiring special skill. It is to be able to judge.

[Means for Solving the Problems]

The porous plug of the present invention has an upper-stage breathable refractory and a lower-stage breathable refractory that have different cross-sectional shapes inside a dense refractory placed inside a metal case connected to a gas blowing pipe. In the gas injection porous plug arranged in two stages, the plane cross section of the lower breathable refractory material is divided into a plurality of parts by a dense refractory material.

The breathable refractory material or the dense refractory material in the horizontal section can have any shape or form.

Further, a gas pool (space portion) may be provided at any place of the breathable refractory and the dense refractory to improve the breathability of the porous plug.

[Action]

Thus, when the degree of melting damage is confirmed by the difference in luminance between the dense refractory material and the breathable refractory material at the melting damage portion, the difference is spread over a plurality of places, which facilitates confirmation. Furthermore, by combining a single and plural occupied parts of any refractory in the cross section and changing the number of plural parts, the degree of melting loss can be confirmed by the change of the number of bright or dark parts. Therefore, it is possible to know the change in the degree of the melting loss relatively accurately.

Furthermore, it becomes possible to more precisely adjust the occupied area in the cross section of the breathable refractory and the dense substance, and the breathability of the entire porous plug can be adjusted accordingly, depending on the type of molten metal to be treated. Facilitates the manufacture of porous plugs.

〔Example〕

 1 to 6 show an embodiment of the present invention.

FIG. 1 shows the first embodiment, and FIG. 2 is a horizontal cross-sectional view taken along line II-II at the boundary surface between the upper porous brick 1 and the modified porous brick 2 in FIG. Here, the porous brick belongs to a breathable refractory material.

In FIG. 1, the porous plug 10 is a dense refractory material 3
The breathable refractory surrounded by is formed into a two-stage structure of a trapezoidal upper-stage breathable refractory 4 and a lower-stage breathable refractory 5 which are divided at a substantially central position. Further, the area of the upper surface of the lower-stage breathable refractory 5 is such that the gas from the gas blowing pipe 1 smoothly passes through the porous plug and is blown into the molten steel from above. 4 is formed to be larger than or equal to the area of the upper surface of No. 4. Then, as shown in FIG. 2, the lower-stage breathable refractory material 5 is divided and the dense refractory material 3 is interposed in the middle thereof. When the porous plug 10 is in a red-hot state, in order for the observer to confirm the contour of the refractory material from a position away from the hot air so that the observer can see it, the interval between the divided parts of the lower breathable refractory material 5 is 5 mm or more. Is desirable.

FIG. 3 shows the second embodiment, in which the porous plug 20 has a recess 6 at the center of the upper surface of the lower breathable refractory 5.
Is formed. This makes it easier to assemble the divided lower breathable refractory 5 into the plug. FIG. 4 shows the structure of a horizontal section taken along the line IV-IV in FIG. Referring to the figure, the dense refractory material 3 is formed in a form crossing the upper surface of the lower-stage breathable refractory material 5 having a circular cross section.
The form which intervenes is shown. The horizontal section taken along the line IV-IV in FIG. 3 may have a sectional structure as shown in FIG. The recess 6 of FIG. 5 shown as the third embodiment is also formed on the upper-stage breathable refractory 4 side, and the dense refractory 3 is formed in both recesses.
It is also possible to have a structure filled with.

By this, it is possible to more surely grasp the melting damage state,
Moreover, it is possible to prevent the upper-stage breathable refractory and the lower-stage breathable refractory from peeling off during operation (gas blowing).

Further, FIG. 6 shows a sectional structural view of another example. The central part of the breathable refractory is divided into cruciform shapes and is filled with dense refractory material. In the present invention, this cruciform shape also constitutes one form of substantially separated parts. Therefore, by combining with the above-mentioned embodiment, or by just doing so, the bonding strength of the upper and lower breathable products becomes stronger, the number of division surfaces increases, and confirmation becomes easier.

As a manufacturing method, first to third embodiments (FIGS. 1 to 6)
In, press molding, the porous bricks that have been molded by casting, etc. in advance are installed in the form of the porous plug, and the method of casting with a dense cast refractory, or the molded porous bricks of dense refractory There is a method of embedding it in the compound and simultaneously pressing.

[Effect of device]

The porous plug of the present invention has the following effects.

(1) Breathable refractory material or dense refractory material or both occupying surfaces in the cross section are divided into a plurality of places (or the cross-sectional shape corresponding thereto is included), so that the breathable refractory material has a dense dark color and red heat state. It is possible to observe that a plurality of high-quality anti-corrosion materials emerge, which makes it possible to more accurately confirm the replacement time of the porous plug.

(2) A distinguishing function can be provided without affecting the basic design of the porous plug for gas ventilation.

(3) A wide ventilation area can be secured, and it is easy to confirm the residual. In addition, since there are no extra joints in the gas jet, there is no infiltration of molten steel from the joint portion, uniform gas bubbling is possible, and it is easy to confirm the residual gas.

[Brief description of drawings]

1 to 6 are views showing an embodiment of the porous plug of the present invention. 7 and 8 show a conventional example. 1: Gas injection pipe, 2: Metal case 3: Dense refractory 4,5: Breathable refractory

Front Page Continuation (56) References Practical application Microfilm (JP, U) Practical application filming the specification and drawings attached to the application for Sho 57-60744 (Act 55-137222) Microfilm (JP, U) Application No. Sho 61-63343 (Act No. Sho 59-No. No. Sho 63-26240 (Act. No. Sho 61-115467) No. 147310) and the specification attached to the application of Microfilm (JP, U) Practical Application No. 48-77454 (Practical No. 47-1218) A microfilm (JP, U) of the contents of the drawing

Claims (1)

[Scope of utility model registration request] 1. An upper-stage breathable refractory (3) having a cross-sectional shape different from each other inside a dense refractory (3) arranged in a metal case (2) connected to a gas blowing pipe (1). 4) and a lower-stage breathable refractory (5) arranged in upper and lower two stages, in a gas-blowing porous plug, the plane cross-section of the lower-stage breathable refractory (5) is divided into a plurality of parts by a dense refractory (3). Porous plug.