JPS59145481A - Siphon type converter slag cutting device - 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 The present invention relates to a siphon-type converter slag cutting device that prevents slag from flowing out during steel tapping in a converter.

If the slag generated during converter blowing flows into the ladle during tapping, impurities will be mixed into the molten steel.1 Reduction in ferroalloy yield, rephosphorization, increased use of converter subsidiary materials, and ladle. This can cause adverse effects such as melting of bricks and a reduction in the refining effect in the ladle1.For this reason, various slag cutting techniques (separating slag from tapped molten steel) have been developed and put into practical use. However, they had the following problems.

1) Method using a slug cut ball.

During the latter half of tapping, balls with a specific gravity between those of slag and molten steel are put into the converter, and the balls float on the flow of molten steel between the molten steel and slag layer, and are released when the molten steel finishes flowing out. This method reaches above the steel tap and closes the tap from above to prevent slag from flowing out.

The drawback is that it is unreliable because it relies on the ball floating.

2) A method in which a sliding nozzle is installed at the tap port of the converter.

In this method, a sliding nozzle is installed at the tap port of the converter, and the slag flowing out from the tap port of the converter is cut by opening and closing the nozzle. The disadvantages include (1) increased cost of refractories, (2) reduced converter production efficiency due to the removal and attachment of the sliding nozzle to the cassette, and (3) residual metal in the converters.

6) A system in which the converter taphole is a siphon type.

To be able to hydrodynamically prevent slag outflow during tapping,
This method cuts the slag using a siphon-type converter tap. The disadvantages are (1) the lifespan of the tapping port is short, the frequency of replacement is high, and the production efficiency of the converter is reduced (
(2) Molten steel remains inside the siphon.

The present invention is a siphon type system that eliminates the drawbacks of the equipment used in the conventional slag cutting method, and that makes it possible to ensure slag separation and improve the quality of molten steel without reducing the production efficiency of the converter. The purpose of this invention is to provide a converter slag cutting device.

The siphon-type converter slag cutting device of the present invention includes a molten steel receiving tank (slag cut pot) equipped with a siphon pipe for pouring out molten steel at the bottom, and a molten steel receiving tank that is connected to a converter tap and a ladle. It consists of a turning and tilting device that can be freely placed and withdrawn between the two. The details will be explained below with reference to embodiment figures.

FIG. 1 is a layout (side) view showing the configuration of the siphon type converter slag cutting device of the present invention. In the figure, 1 is a converter, 2 is a converter tap, and 6 is a ladle that receives the tapped steel from the converter. 4 is a molten steel receiving tank (siphon-type slag cut bot) of the device of the present invention, which has a fireproof lining inside the steel shell, and a slag cut pot at the bottom of which pours the molten steel from the converter into the ladle. A dead siphon tube 5 is provided.

The siphon tube 5 is made of heat-resistant steel or the like. The slag cut pot serves as a relay for pouring molten steel between the converter and the ladle. Reference numeral 6 denotes a rotating and tilting device, which is equipped with the slag cut pot 4 and can be rotated to place the slag cut pot at a working position between the converter tapping port and the ladle, or to withdraw it to a standby position; The slag cut pot can be tilted in its standby position.

The procedure for cutting syslag using the siphon type converter slag cutting device of the present invention is as follows.

1) Before tilting the converter 1 for tapping, the turning and tilting device 6 is turned and the siphon-type slag cut pot 4 is rotated.
Ao is placed directly below the converter tapping port 2 from the standby position. 2) The converter is tilted to start tapping.

6) The molten steel once falls from the tapping port 2 to the siphon type slag cut bot 4, passes through the siphon pipe 5, and falls into the ladle 6.

4) At the end of tapping, the metal pressure and slag pressure in the siphon tube 5 are balanced, and tapping is automatically stopped at the same time as pouring from the converter is stopped. This prevents subsequent slag from flowing into the ladle.

5) After tapping, the turning and tilting device 6 is rotated to withdraw the siphon-type slag cut bot 4 to the original standby position, and then the slag cut pot 4 is tilted to remove the slag remaining in the pot. discharge.

6) If the siphon tube 5 is clogged, remove it and replace it. The siphon tube is replaceable. The above exchange is performed in the standby position during blowing of the next charge, which seriously reduces the converter production capacity.6 Next, the principle of the siphon-type converter slag cutting apparatus of the present invention will be explained (see FIG. 2). Figure 2 shows the state of the slag cut pot at the end of tapping.
4 is a slag cut pot, 5 is a siphon tube, S is a slag, and M is a metal. 1. Also, hs is the slug height on the inlet side of the siphon, and hm is the metal height on the outlet side of the siphon. If the slag specific gravity is ρ81 and the metal specific gravity is Pa, then the heights of the entrance and exit sides of the siphon should be set so that the static pressure of the metal inside the siphon exceeds the static pressure of the slag at the end of tapping. If set, tapping will automatically stop, preventing slag following molten steel from flowing into the ladle, and making slag cutting possible.

By using the siphon type converter slag cutting device of the present invention, the following effects were obtained.

1) Reduced slag in the ladle.

Figure 6 is a histogram showing the effect of reducing the amount of slag that enters the ladle during tapping (indicated by the thickness of slag in the ladle) by using the device of the present invention. In the case of l~, Figure (b) shows the case where the apparatus of the present invention is used. As is clear from the figure, the slag thickness in the ladle (average value Ma) decreased from 145 to 27, and the variation σ decreased from 61 to 1.
0+mn, indicating the high reliability of the device of the present invention.

2) Improved yield of ferroalloy (reduced amount of Al used).

Since the outflow of oxidizing slag rich in FeO, MnO, and 1%05 is reduced, the amount of A4 used is reduced and the yield of ferroalloy is improved. FIG. 4 is a graph showing a comparison between no slag cutting and slag cutting using the apparatus of the present invention in the production of low carbon aluminum guild steel for thin plates.
The vertical axis shows the Al basic unit h/T, and the horizontal axis shows the slag thickness in the ladle. In the figure, white circles show results without slag cutting, and black circles show results when slag cutting was performed using the apparatus of the present invention.

That is, when using the device of the present invention, the amount of Al used is reduced,
It can be seen that this results in an improvement in the yield of ferroalloy.

3) Decrease in the amount of rephosphorus.

Rephosphorus is the P in the slag! 0. occurs when it is reduced. Therefore,
If the amount of slag flowing into the ladle is reduced by slag cutting, the amount of rephosphorization will be reduced. FIG. 5 is a graph showing a comparison of the amount of rephosphorization in the production of UOE (X-70) steel without slag cutting and in the case where slag cutting was performed using the apparatus of the present invention. In the figure, the vertical axis shows the amount of rephosphorization, the horizontal axis shows the slag thickness in the ladle, the white circles are the results without slag cutting, and the black circles are the results when using the apparatus of the present invention. The figure shows that when slag cutting is performed using the apparatus of the present invention, the amount of rephosphorization is significantly reduced.

4) Improved refining effect in the ladle.

By performing slag cutting using the apparatus of the present invention, the amount of slag in the ladle is reduced, thereby improving the cleanliness of the steel when performing deep ladle refining.

5) The siphon type slag cut pot is easy to replace.
Since the replacement time is short and it can be replaced during blowing, the steel tapping capacity of the converter will not be reduced.

As described above, the siphon-type converter slag cutting device of the present invention is extremely effective for cutting slag during steel tapping in a converter, and is an extremely excellent device that can be used to improve the quality of steel.

[Brief explanation of drawings]

Fig. 1 is a layout (side) view showing the configuration of the siphon type converter slag cutting device of the present invention, Fig. 2 is a diagram explaining the principle of slag cutting by the device of the present invention, and Fig. 6 is a diagram showing the use of the device of the present invention. Fig. 4 is a graph showing the effect on the slag thickness in the ladle, Fig. 4 is a graph showing the effect on the At basic unit, and Fig. 5 is a graph showing the effect on the amount of rephosphorus. 1: converter, 2: tapping port, 3: ladle, 4: siphon type slag cut pot, 5: siphon tube, 6: turning and tilting device, h8 varnish slag height, hm: metal height. Agent Patent Attorney Sanro Kimura Figure 1 Figure 2 Figure 3 Book 'ktrj11灼7°K (mm1"41"°. 257' to 1.l-t!t-., JP-A-59- 1454
81(4) Figure 5, M ``'2M?'''. / "Hardware tube in the ear '7 - Thickness (mm)

Claims (1)

[Scope of Claims] 1) A molten steel receiving tank (slag cut pot) equipped with a siphon pipe for pouring out molten steel at the bottom, and the molten steel receiving tank is mounted and placed between the converter tapping port and the ladle. A siphon-type converter slag cutting device that is similar to a rotating and tilting device that allows the fist to be freely retracted. 2) When the slag height on the inlet side of the siphon tube at the end of tapping is hsh, the metal height on the outlet side is hm, the slag specific gravity is PB, and the metal specific gravity is 2m, hB・PB<hm-2
2. The siphon-type converter slag cutting device according to claim 1, wherein the heights of the inlet and outlet sides of the siphon tube are set so that the height of the siphon tube is set to be m.