JPS595063B2 - How to start tapping molten metal in a container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for starting the tapping of molten metal stored in a molten metal storage container such as a ladle or tundish, for example, when molten metal is tapped from the bottom of the container.

Conventionally, when storing molten metal in a ladle with a sliding nozzle attached to the bottom, it is common to fill the tap hole above the sliding nozzle, that is, the ladle nozzle, with a non-sintering filler before receiving the steel. be.

Therefore, when using the molten steel in the ladle for ingot making, if you start pouring the molten steel in the above-mentioned state, the above-mentioned fillers will be discharged together with the molten steel, contaminating the molten steel and causing quality problems. Conventionally, the method used is to drain the hot water in advance and then pour it into the mold.

However, this method is laborious and causes time loss and yield loss, so it is difficult to say that it is a preferable method.

In addition, when molten steel in a ladle is used for continuous casting, if the metal is discarded in advance, yield loss will naturally occur, and in particular, time will be lost, making it difficult to carry out so-called continuous casting in an optimal manner in terms of quality and work. do not have.

Therefore, the conventional method has been to start pouring with the long nozzle between the ladle and tundish removed, and then set the long nozzle and operate normally.

The disadvantages of this case are not only the above-mentioned contamination of the molten steel due to the filler being injected into the tundish, but also
- The slag floating on the molten steel in the tundish is driven into the molten steel, causing quality deterioration of the casting joints at the initial stage of casting and successively.

etc.

On the other hand, in the case of Tanditshu, it is very difficult to start with something packed in the nozzle because the nozzle may become clogged.
Even if it were possible, the filler would be directly injected into the mold, resulting in a defective slab containing inclusions.

On the other hand, if you start pouring with the sliding nozzle open, the initial molten steel tends to solidify inside the nozzle (
Therefore, the nozzle becomes clogged.

For this reason, conventionally, the sliding nozzle was opened and the upper part of the upper nozzle of the tundish was covered with a steel plate to receive the molten steel, and once a certain amount of steel head was secured, the steel plate was melted and damaged. It uses a natural injection start method.

The problems with this method are: ■ It is laborious to prepare and set the steel plate for the lid with a predetermined thickness; ■ The injection starts naturally due to melting of the steel plate, so the injection start time varies over time. ■Since it is not possible to start with the molten steel fully filled in the tundish, there is a concern that the time for inclusions to float is not secured, leading to quality deterioration.

The present invention was made in view of the above-mentioned situation, and its features include a tap hole provided at the bottom of the container, a sliding opening/closing device for the tap hole, and a tip facing the inner wall of the tap hole. When tapping the stored molten metal using a molten metal storage container equipped with an inert gas supply system,
An inert gas is supplied into the tap, and the weakly sintering or non-sintering filling that has been filled in the tap is blown up into the molten metal in the container and dissolved or separated and floated. The object of the present invention is to provide a method for tapping molten metal in a container, which involves opening a dynamic opening/closing device to tap out molten metal, and which makes it possible to improve workability, yield loss, and improve quality.

As a result of various studies prior to the completion of the present invention, the inventors of the present invention broke away from the conventional fixed idea that the filling at the spout is discharged out of the container by the flow of molten metal, and instead decided to They were able to discover that it undergoes melting treatment or separate floating in molten metal.

That is, a weakly sinterable filling such as silicic acid is used, the steel is placed in a container, and immediately before the start of injection, an inert gas such as argon gas is blown into the upper nozzle (porous nozzle) of the sliding nozzle. After filling the filling with the blown gas and causing it to float into the molten metal in the container, the sliding nozzle is opened to start injection.

During this time, the filling powder pushed into the molten metal is melted and consumed.

Next, an example will be described.

■ SN (sliding nozzle) upper nozzle: Porous nozzle (corundum, mullite beads) ■ SN upper nozzle filling: silicic acid ■ Blow gas: Inert gas (N2.Ar) ■ Blow Gas pressure Ladle ~3~7kg/CrIL tandit ~0.5~5 kg/CTL ■〃 Flow rate Ladle~100~10001/rn
Inert gas was blown into the SN upper nozzle under the above conditions to melt and consume the filling in the upper nozzle portion, and the injection was started.

The present invention can be applied to a container equipped with a sliding nozzle such as a ladle for ingot making, a ladle for continuous casting, and a tundish. For example, in a ladle for ingot making, workability is improved because waste hot water is not required. , time and yield losses were eliminated.

In addition, the continuous casting ladle prevents the molten steel from becoming contaminated due to filling, and since pouring can be started with the long nozzle set, ■ it is possible to prevent the oxidation and contamination of the molten steel due to open casting, and prevent slag from being trapped. Improvements in slab quality were observed.

Furthermore, in the case of Tanditshu, by securing sufficient molten steel at the start, stable work and improved quality were observed, and in all cases there was an extremely large effect in terms of workability and improved quality.

Claims (1)

[Scope of Claims] 1. A molten metal storage comprising a tap hole provided at the bottom of the container, a sliding opening/closing device for the tap hole, and an inert gas supply system with its tip facing the inner wall of the tap hole. When tapping the stored molten metal using a container, an inert gas is fed into the tap opening to melt the weakly sinterable or non-sinterable filler that has been filled in the tap opening in advance in the container. A method for starting dispensing molten metal in a container, which comprises blowing up the molten metal into the metal, causing it to melt or separate and float, and then opening a sliding opening/closing device to dispense the molten metal.