JPS5937321Y2 - sliding nozzle device - Google Patents

Description

[Detailed Description of the Invention] The present invention is directed to a Nuriding Nozzle (hereinafter referred to as SN) device installed in a ladle or tundish.
The present invention relates to a device for preventing C adhesion and accumulation of non-metallic inclusions in a lower nozzle hole of the device and a long nozzle hole below the lower nozzle.

Recently, there have been many cases in which elements such as Al or Ti are added to molten steel to improve the quality of steel or to melt special steel.

Oxides or nitrides of these additional elements are added to the SN during casting.
It adheres and accumulates in the lower nozzle hole and long nozzle hole of the device, making the nozzle hole narrower and making it impossible to obtain a predetermined injection rate.

In severe cases, the nozzle hole may become clogged, making injection impossible.

A conventional method for solving the above problem is to heat one nozzle.

Apply ultrasonic waves to 2 nozzles. There are methods such as constructing the inner surface of the nozzle with a special refractory material to which non-metallic inclusions are difficult to adhere, but none of these methods yields sufficient effects.

On the other hand, a ring-shaped gas-permeable refractory (hereinafter referred to as porous brick) was installed above the ladle nozzle (1985).
l-20014) or installed on the upper plate of the SN device (Special Publication No. 49-21016).
In the former case, the blown gas is mainly used for stirring and refining the molten steel in the ladle, and in the latter case, the purpose is to prevent solidification of the molten steel in the upper plate hole until the start of injection.

According to the experience of the inventor of the present invention, it has been found that the conventional method of mounting a porous brick above the sliding plate in an SN device has a small effect of preventing the nozzle hole from clogging.

The reason for this is that the outflow speed is slow at the beginning of injection, so the sliding plate of the SN device is positioned as shown in Figure 1 to narrow the molten steel outflow hole.

In this case, the molten steel becomes turbulent as shown in the figure, and the sliding plate 1
slides to the left together with the lower nozzle 7, and the sliding plate 1
On the side where the lower nozzle 7 is retracted from the fixed plate 6, the gas ejected from the porous brick 2 flows down the path shown in the figure, so the action of washing away non-metallic inclusions is small, especially on the sliding plate 1. It was found that nonmetallic inclusions K adhered and accumulated on the lead-in side.

The present invention is based on such knowledge, and a porous brick is attached to the molten steel flow hole of the plate brick of the SN device, which has a sliding surface on the upper surface and a non-sliding surface on the lower surface and is directly connected to the lower nozzle. A gas introduction pipe is connected to the porous brick, and the molten steel flow hole of the plate brick and the molten steel flow hole of the lower nozzle are always maintained concentrically.

The present invention will be explained below with reference to the drawings.

Fig. 2 shows an example in which a polar spring 2-1 is attached to the sliding plate brick 1 of the SN device, and Fig. 3 shows an example in which a porous spring 2-1 is attached to the lower fixed plate brick 3 of the SN device.
-2 is shown.

Each porous brick 2 has a ring shape and is installed inside concentrically with the sliding plate brick 1 and the lower fixing plate brick 30, respectively.

Further, a gas introduction pipe 4 for feeding an inert gas is connected to the porous brick 2.

The method for installing the porous bricks may be to mold each plate brick and porous brick and then fit them together, or to mold each plate brick at the same time by changing the grain size of the porous brick portion during molding.

The position of the inner thigh of the porous brick should be such that it is not exposed to the sliding surface of each plate brick.

That is, the porous brick 2 has lower erosion resistance and crushing strength than refractories such as sliding plate bricks.

Therefore, if the polar spring is exposed to the sliding surface,
The porous brick is severely eroded by the molten steel flow.

In addition, since the sliding surface is made watertight with great force, a great force is applied to the porous brick, causing damage.

The porous brick is attached to the molten steel flow hole of the sliding plate brick 1 or near the bottom of the sliding plate brick, that is, the molten steel flow hole of the lower fixed plate brick 3, so that even if it falls over, the upper surface is a sliding surface and the lower surface is a non-sliding surface. Provided on the plate brick facing the surface.

When a porous brick is attached to the molten steel flow hole of the sliding plate brick 1, the lower surface is a non-sliding surface, and the lower nozzle 7 following this works together with the sliding plate brick 1, and the molten steel flow holes of both are always concentric. It is now possible to maintain the condition.

In addition, when a porous brick is attached to the fixed plate brick 3, the lower surface of the fixed plate/freeze 3 is a non-sliding surface and the lower nozzle 7 following it is fixed, so the molten steel flow hole of the fixed plate brick 3 and the lower part The nozzle 7 is maintained concentrically with the molten steel flow hole.

Note that 5 indicates a nozzle of, for example, a tundish that accommodates molten steel, and 6 indicates an upper fixing plate brick of the SN device.

In the apparatus shown in FIGS. 2 and 3, when, for example, Ar gas is blown into the flowing molten steel from the gas introduction pipe 4 through the porous brick 2 during injection of molten steel, the gas becomes bubbles and flows into the molten steel. and falls near the inner surface of the nozzle.

This prevents nonmetallic inclusions in the molten steel from adhering to the inner surface of the nozzle, and also washes away the adhered nonmetallic inclusions.

The gas blown in in the present invention is a gas that does not adversely affect the components of molten steel, and for example, an inert gas such as Ar gas is suitable.

Example While pouring SUS 430 stainless steel containing 0.38% of Al into the mold from the tundish, the SN
A from the porous brick installed in the sliding plate of the device
R gas was injected.

As a result, the amount of non-metallic inclusions attached to the lower nozzle and long nozzle after completion of injection was extremely small.

This nozzle was later usable for 1ch.

In comparison, when the porous brick is installed inside the upper fixed plate under the same conditions as above, the nozzle diameter is 40 mm.
There were 10 to 30 degrees of deposits on the inner surface of the nozzle, making it impossible to use it later.

Ar gas pressure crab 0.1 kg/cmf Ar gas flow rate; 271/min In addition, the present invention has the effect that the sliding plate that protrudes into the molten steel flow hole and is easily damaged by melting is protected by the gas curtain action of the blown gas, Furthermore, since the molten steel does not come into contact with the porous brick when the SN nozzle is closed, it has the advantage that the erosion of the porous brick is significantly smaller than when it is installed on the upper fixed plate or the upper nozzle.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing how non-metallic inclusions adhere to the inner surface of the nozzle when a porous brick is installed above the sliding plate, and FIGS. 2 and 3 are cross-sectional views of the device of the present invention. 1...Sliding plate, 2...Porous brick, 3...Lower fixing plate, 4...
... Gas introduction pipe, 5 ... Upper nozzle, 6 ...
...Top fixing plate, 7...Bottom nozzle.

Claims (1)

[Scope of utility model registration request] A gas-permeable refractory is installed in a ring shape in the molten steel flow hole of the plate brick, which has a sliding surface on the upper surface and a non-sliding surface on the lower surface and is directly connected to the lower nozzle, and gas is introduced into the gas-permeable refractory. A sliding nozzle device characterized in that the pipes are connected, and the molten steel flow hole of the plate brick and the molten steel flow element of the lower nozzle are always maintained in a concentric state.