JPH0342157A - Method for preventing drift stream in mold for continuous casting and submerged nozzle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention supplies an inert gas to prevent drifting of molten steel supplied into a mold in continuous casting, adjusts the amount of the inert gas, and prevents molten steel from drifting. This invention relates to a method for uniformly supplying molten metal by eliminating drifting of molten metal, and an immersion nozzle used therein, and relates to a method for preventing drifting in a mold for continuous casting and an immersion nozzle (prior art). A submerged nozzle that supplies an inert gas to the nozzle to prevent alumina from adhering to the nozzle inner hole and discharge port is disclosed in the following publications. For example, in the immersion nozzle disclosed in Japanese Utility Model Application Publication No. 58-134246, a porous material is provided at the lower end of the slit for injecting inert gas at the upper part of the molten metal discharge port inside the molten steel injection hole drilled in the center. The inert gas blown from the porous material at the bottom of the slit is at the top of the discharge port, and the inert gas is only blown into the inside of the molten steel injection hole.
Since the discharge port cannot be selected to the left or right for blowing, it is impossible to prevent the injected molten steel from drifting by using an inert gas.

Further, the continuous casting nozzle in Japanese Utility Model Publication No. 63-40292 is provided with a hollow chamber that communicates with a plurality of inert gas introduction holes, or the hollow chamber does not have an inert gas discharge port shown in the drawing. Even if there is a hole through which the inert gas in the hollow chamber is blown into the molten steel injection hole, the inert gas will only be blown into the molten steel in the molten steel injection hole and will prevent the molten steel from drifting at the molten steel discharge port. I can only adjust it.

Furthermore, a molten metal injection nozzle equipped with a mesh pore for blowing gas in Japanese Patent Application Laid-Open No. 62-203663 has a hollow chamber in the circumferential direction between an inner wall member and an outer wall member, and a hollow chamber in the circumferential direction is provided in this part. With holes, inert gas can only be blown into one gas socket, and inert gas can be blown selectively into the left and right outlets to prevent uneven flow. I can't adjust it because of it.

In the techniques described in the above-mentioned publications, it becomes necessary to clean the discharge port when drifting starts due to the adhesion of alumina, etc., and even if alumina etc. do not adhere, the molten steel does not flow uniformly from the discharge port, and When used for a long time, drifting occurs due to melting damage, etc., and there are defects such as the inability to uniformly cast molten steel.

(Problems to be Solved by the Invention) The present invention provides a method for preventing drift in a mold for continuous casting, with the aim of preventing drift of molten steel flowing into a mold from a submerged nozzle, and obtaining a uniform cast product. and a submerged nozzle for use in the method (Means for Solving the Problems) The present invention provides a nozzle disposed below a tundish in continuous casting, when supplying molten metal into a mold at the center. The inert gas is supplied from a plurality of inert gas supply ports opened above the immersion nozzle body, which has vertical molten steel injection holes, and a vertical slit that communicates with the inner end of the inert gas supply ports. The inert gas is transferred to the left and right or front and back of the immersion nozzle body, and the inert gas that has passed through the porous portion provided across the upper surface of the plurality of molten steel discharge CIs provided below the immersion nozzle body and the lower end surface of the slit is This is a method for preventing drift in a mold for continuous casting, which is characterized by selectively adjusting the amount of inert gas at a discharge port to allow molten steel to flow out into the mold in an adjustable manner.

In addition, a vertical molten steel injection hole 2 is opened in the center of the immersion nozzle body 1 arranged below the tundish used in the method for preventing drifting in a mold for continuous casting, and 2 (1!! A plurality of inert gas supply ports 3 are opened in the submerged nozzle body l, and a vertical slit 4 is opened in the submerged nozzle body l, and the inner end of the inert gas supply port 3 communicates with the inert gas supply port 3. This immersion nozzle is characterized by having a porous portion 6 extending over the molten steel discharge port 5 provided at the lower end of the molten steel injection hole 2!

Although the porous portion 6 is provided in the upper half of the discharge port 5 in the embodiment, it may be provided around the entire circumference of the discharge port.

Furthermore, it is preferable to provide a slit section on the back surface of the porous section and blow the gas through the slit section, since the gas can be uniformly blown from the entire surface of the porous section.

(Function) In continuous casting, when molten steel is injected into the mold from the immersion nozzle placed below the tundish, and continuous casting is performed, the molten steel injection hole is formed in the center vertical direction of the immersion nozzle body 1. When injecting the molten steel (molten metal) in the tundish into the mold 7 from 2, the inert gas supply ports are placed on the right or left, or before or after the inert gas supply ports 3 provided above the immersion nozzle body 1. 3 is selected and inert gas is blown in, and the inert gas is communicated with the inner end of the inert gas supply port 3, and the inert gas is directly blown into the molten steel discharge port 5 from the lower end through the slit 4, and from the discharge port 5. Since an inert gas is blown into the molten steel flowing out, the amount of molten steel flowing out from the discharge port 5 is adjusted according to the amount of inert gas blown into the molten steel, which allows the molten steel to flow uniformly into the mold 7 and prevents uneven flow of the molten steel. prevent.

In the present invention, inert gas can be blown directly into the molten steel flowing out from the selected discharge port 5 because the porous portion 6 is provided across the lower end of the slit 4 and the molten steel discharge port 5. Since the flow rate of molten steel can be adjusted by the amount of inert gas added, it is possible to reliably adjust the drift of molten steel.

(Example) The present invention provides two inert gas supply ports 2 to the submerged nozzle body l.
Although a plurality of inert gas supply ports 2 are provided, a case where there are two left and right inert gas supply ports 2 will be explained.

Immersion nozzle main body 1 located below the tanditshu 8
When the molten W49 (molten metal 9) in the dumpster 8 flows into the mold 7 from the molten steel injection hole 2 opened in the longitudinal direction at the center of If it is confirmed that the flow is biased to the right at the inert gas supply port 3, open the valve 10 of the inert gas supply port 3 on the right side to suppress the flow rate of the melt w49 to adjust the drift, or open the valve on the left side. Adjust the flow to the left and right while narrowing down to 10. At this time, the amount of inert gas supplied varies depending on the amount of molten steel 9 passed through, but it is adjusted within the range of 2 to 20 strokes/min for the total left and right, and it is preferable that the total amount of left and right is as small as possible.

The difference in the amount of inert gas supplied is also controlled to be as small as possible, preferably within the range of 0 to 5JL7sin, to prevent drift in the continuous casting mold.

(Effects of the Invention) As described above, the present invention supplies inert gas directly to the molten steel discharge ports formed at the lower end of the molten steel injection hole in the central vertical direction of the immersion nozzle body while adjusting the gas amount, Adjust the difference in the amount of molten steel discharged at each discharge port as much as possible,
This is because drifting of molten steel within the mold can be reliably prevented.

The quality of the cast product can be made uniform, and the work of preventing drift of molten steel can be easily and effectively carried out.

Therefore, the fear of drifting of molten steel as in the prior art is eliminated, and the object of the present invention can be fully achieved.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an example of an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line A--A in the same manner, and FIG. 3 is a vertical cross-sectional view taken along line B--B in FIG. 1... Immersion nozzle body, 2... Molten steel injection hole, 3...
・Inert gas supply port, 4...Slit, 5...Discharge port, 6...Porous part, 7...Mold, 8...
Tanditshu, 9... Molten steel, 10... Valve,
11... Corrosion resistant member.

Claims (2)

[Claims] (1) When supplying molten metal into the mold with a submerged nozzle placed below the tundish in continuous casting,
Inert gas is supplied from a plurality of inert gas supply ports opened above the immersion nozzle body having a vertical molten steel injection hole in the center through a vertical slit communicating with the inner end of the inert gas supply ports. Continuous casting characterized in that the amount of inert gas is allowed to flow directly and selectively into a plurality of discharge ports of the molten steel supplied from the molten steel injection hole through a porous portion provided at the lower end of the slit. Method for preventing unevenness in the mold. (2) Drill a vertical molten steel injection hole in the center of the immersion nozzle body located below the tundish in continuous casting,
A plurality of inert gas supply ports are provided above the immersion nozzle body, a vertical slit is formed at the inner end of the inert gas supply port, and a molten steel injection hole provided at the lower end of the slit and the lower end of the molten steel injection hole is formed. An immersion nozzle for preventing drifting in a mold for continuous casting, characterized in that a porous part is provided at the discharge port.