JPH077018Y2 - Porous plug for blowing gas - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a porous plug used for blowing an inert gas into a molten metal.

(Prior Art) An inert gas is blown into a molten metal for the purpose of adjusting the temperature of the molten metal, making the components uniform, removing non-metallic inclusions, and the like.

To show the general structure of the porous plug used in this method, as shown in FIG. 3, a porous refractory 2 having a gas permeation function is surrounded by a dense refractory 1 that does not permeate gas.
The lower end is covered with a bottom iron plate 4 to which the gas introduction pipe 3 is connected, and the outer periphery is provided with a side iron plate 5 fixed to the bottom iron plate 4. For example, as disclosed in Japanese Utility Model Laid-Open No. 59-47647.

(Problems to be Solved by the Invention) A porous plug has a problem that a thermal leak due to a high temperature during use causes a gap between a refractory and an iron plate portion to cause a gas leak. The gas leak abnormally melts the refractory located around the porous plug, and when the gas injection is stopped, the metal plug is inserted into the gas leak portion, and the life of the porous plug is shortened.

There is also a problem that the refractory portion of the porous plug floats up due to the gas pressure. If it floats even a little, gas will flow toward the outer circumference of the porous plug, which will promote gas leakage. The large rise may cause the entire refractory to come out upward, in which case a serious accident due to leakage of hot water may occur.

In order to solve the above problems, various measures have been conventionally made. The same is true of the invention disclosed in Japanese Utility Model Laid-Open No. 59-47647. However, it has not been fully resolved yet.

(Means for Solving the Problem) The present invention solves the problems of gas league and lifting of refractories all at once by changing the shape of the iron skin attached to the porous plug. The structure thereof will be described with reference to the drawings of the embodiments. A porous refractory 2 whose outer periphery is surrounded by a dense refractory 1 and a lower surface of the porous refractory 2 are covered, and a gas introduction pipe 3 is connected. Bottom iron plate 4 and side iron plate 5 having its lower end fixed to the bottom iron plate 4 and extending upward.
In the gas-blowing porous plug, the side-face iron plate 5 is inclined toward the inside to be included in the dense refractory material 1.

(Function) Unlike the conventional one in which the side iron plate is provided on the outer periphery of the dense refractory, the side iron plate is internal to the dense refractory, so even if it is subjected to thermal expansion due to the high temperature during use, There is no problem of opening between quality refractories.

The side iron plate inclined toward the inside of the dense refractory works as a hook to prevent the refractory from rising.

(Examples) Examples of the present invention will be described below.

In FIG. 1, the porous refractory 2 has a gas permeation function. The porous refractory material is manufactured by a conventional method, for example, by adjusting the particle size of the refractory aggregate or mixing the burnable cell-forming material into a porous structure. The shape is not limited to the one shown in the figure, and for example, the shape of the upper side and the shape of the lower side may be different in order to make it easier to determine the melting damage state.

The dense refractory 1 has a role of protecting the porous refractory 2 having poor strength and a role of preventing gas passing through the porous refractory 2 from leaking to the outer peripheral side of the porous plug. In order to facilitate mounting on the bottom of the molten metal container, the side surface has a taper on its outer periphery.

In order to allow the inert gas to enter from the entire lower surface of the porous refractory material 2, it is preferable to form a gas pool chamber 6 by providing a fixed space between the bottom iron plate 4 and the lower end of the porous refractory material 2. In order to provide a space between the bottom iron plate 4 and the porous refractory material 2, the bottom iron plate 4 may be lowered as shown in the figure, or the lower end of the porous refractory material 2 may be provided on the outer periphery of the dense refractory material 1. There is a method such as making it shorter.

The side iron plate 5 is fixed at its lower end to the bottom iron plate 5. In the embodiment shown in FIG. 1, the entire upper side of the side iron plate 5 is inclined toward the inside of the dense refractory 1 and is made to exist inside the dense refractory 1. In the embodiment shown in FIG. 2, only the upper end portion of the side iron plate 5 is tilted so as to be included in the dense refractory material 1. The inclination angle of the side iron plate 5 is not particularly limited, but in order to obtain the full effect of the present invention, the side iron plate 5 is inclined so that the tip of the side iron plate 5 is substantially in the center of the thick portion of the dense refractory material 1. Preferably.

Although not shown in the figure, the surface of the side iron plate 5 may be coated with ceramic fibers or asbestos. The ceramic fiber / asbestos acts as an expansion allowance of the side iron plate 5. Further, although it is not preferable because the number of parts increases, a shielding iron plate may be additionally provided inside the side iron plate as seen in, for example, Japanese Utility Model Laid-Open No. 59-47647.

In order to manufacture the above-mentioned porous plug, for example, after setting the porous refractory 2 and the iron plates 4,5 having a shape according to the present invention in a casting mold, the porous refractory 2 and the iron plates 4,5 are set. This can be easily performed by casting a refractory material as the dense refractory material 1 between and.

The entire refractory part has a bottom surface diameter of 210 mm, a top surface diameter of 163 mm,
In a porous plug having a truncated cone shape with a height of 200 mm and a thick portion of the dense refractory 1 of 36 mm, the embodiment of the present invention described above and the conventional type in which the side iron plate 5 covers the outer periphery of the dense refractory 1 are used. A comparison test was conducted. As a result, in the conventional tie type, the refractory material arranged around the porous plug was largely melted due to gas leakage from the outer periphery of the porous plug. In addition, when the material was cut open after use and investigated, a 2 mm gap was formed between the dense refractory and the bottom iron plate. On the other hand, in the case of the embodiment of the present invention, almost no gas leakage or floating was observed, and the service life thereof was more than twice that of the conventional type.

(Effect) As described above, the present invention has an effect of preventing gas leakage and floating. Therefore, the use of the porous plug of the present invention greatly improves the efficiency of molten metal processing due to its reliability and service life.

[Brief description of drawings]

Each of the figures is a longitudinal sectional view, and FIGS. 1 and 2 show an embodiment of the present invention and FIG. 3 shows a conventional example. 1 …… Dense refractory 2 …… Porous refractory 3 …… Gas introduction tube 4 …… Bottom iron plate 5 …… Side iron plate

Claims (1)

[Scope of utility model registration request] 1. A porous refractory 2 whose outer periphery is surrounded by a dense refractory 1, a bottom iron plate 4 which covers a lower surface of the porous refractory 2 and which is connected to a gas introduction pipe 3, and a lower end thereof. In a porous plug for gas blowing, which comprises a side iron plate 5 fixed to the bottom iron plate 4 and extending upward, the side iron plate 5 is inclined toward the inside to be included in the dense refractory material 1. Porous plug for blowing gas.