JPS58221217A - Pressure refining and casting device - Google Patents

Abstract

PURPOSE:To provide a titled device which enables the rephosphorization, resulfurization, the prevention of the decrease in the yield of volatile metal, etc. in the stage of casting by providing a movable lance to a pressurized vessel for contg. molten steel, and constituting a charger for additives and a casting mold at the top end thereof attachably and detachably and exchangeably. CONSTITUTION:Gaseous Ar is introduced through a gas introducing pipe 4 into a pressurized vessel 1 to maintain the pressure therein at about 3atm. The bottom end of a freely vertically movable lance 5 is immersed in the molten steel 3 in a ladle 2 contained in the vessel 1, and the dephosphorizing and desulfurizing flux and volatile metal, etc. in an additive hopper 7 mounted with a connection part 13 for attaching and detaching which is made freely hermetically mountable are added into the steel 3 under exertion of about 7atm pressure by the gaseous Ar introduced through a piping 8 for a gaseous carrier so that the steel is refined under the pressure. The hopper 7 is removed in the part 13, and a casting mold 9 is mounted by means of a branching plate 12. The pressure therein is kept at about 3atm by a pressure regulating valve 10 and the gaseous Ar is further supplied through the pipe 4 into the vessel 1 to increase the pressure to 7atm, by which the molten steel 3 is lifted into the mold 9 and is thus cast.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure refining and casting apparatus. Conventionally, steel refining techniques are well known in which molten steel is charged into a pressurized vessel, pressure is increased, and flux or volatile metals such as Ca and Mg are added.

However, these techniques are applied only to the refining process, and the casting process is performed under atmospheric pressure.

For this reason, even if the pressure is increased in the refining process and flux or volatile metals are added to increase the efficiency of flux in removing CP and removing S, or to increase the yield of volatile metals, during casting, the During casting, the yield of volatile metals with high vapor pressure decreased as well as rephosphorization and resulfurization occurred during casting. For example, the vapor pressure of Ca is 1550°C.

1.05 atm at 1.81 atm at 1600°C
, 2.32a1. at 1650°C. m, and exhibits a high vapor pressure at steelmaking temperatures (~1650°C).

The present invention advantageously solves these difficulties,
It effectively performs refining and casting in a pressurized container, and its main points are: a pressurized container containing a ladle of molten steel to be cast, a gas introduction device with a pressure adjustment valve to the pressurized container, and a pressurized container. A movable lance that fits into a hole provided in the outer shell of the container and can move up and down is installed, a switching valve in the middle of the lance, and a detachable connection part with a casting mold with an additive injection device and a pressure regulating valve at its upper end. This is a pressurized refining and casting apparatus characterized by comprising:

The gas introduction pipe in the present invention is provided with a pressure regulating valve in order to increase the pressure inside the pressurized container and maintain a constant pressure. Ar is supplied from this gas introduction pipe.

It is preferable to introduce an inert gas such as N2.1. Yes, but
It may also be a gas mixed with some oxygen, such as air.

In addition, the pressure inside the pressurized container is increased to above atmospheric pressure,
In the case of adding Ca, since the vapor pressure of Ca at the steel-making temperature is i,05 atm to 2.32 atm, it is preferable to set the pressure in the pressurized container to 2 atm or more.

Moreover, the gas introduction pipe and the pressure regulating valve do not need to be integrated and may be installed separately in the pressurized container.

This lance has the function of injecting additives with carrier gas into the lance and introducing the self-molten steel from the ladle into the casting mold. However, since the lance is preheated at the time of injection, it can be easily cast. Further, as an applied example of the present invention, it is also possible to separately arrange a lance exclusively for injection and a lance exclusively for casting. The switching valve in the middle of the lance is used to maintain the pressure inside the pressurized vessel and to control the outflow of additives and inflow of molten steel, and is preferably an airtight sliding nozzle or the like.

The additive hopper is charged with flux and volatile metal for removing [P] and removing [8], and is injected into the molten steel via a switching valve lance with a carry gas.
The hopper and lance are mounted on the top of the switching valve so that they can be installed in a hermetically sealed manner. Furthermore, the above-mentioned flux etc. can be easily added by increasing the carrier gas pressure to 4 to 5 atm or more higher than the pressure inside the pressurized container.

The hopper may be placed above the lance, but it may also be attached to the lance via piping from the hopper so that it can be installed in a hermetically sealed manner.

Like the additive hopper, the casting mold can be installed in a hermetically sealed manner at the top of the switching valve. During refining, the casting mold can be placed in the additive hopper, and during casting, it can be replaced alternately at the top of the switching valve, or a special lance can be installed. hopper and mold may be installed.

Casting molds use the pressure difference by opening and closing a switching valve to sequentially inject molten steel into a mold placed at a higher position than the ladle surface. It is also necessary to increase the pressure inside the pressurized container. In addition, a pressure regulating valve is installed in the mold to increase the pressure inside the mold, and by further increasing the pressure inside the pressurized container, it is possible to cast at a pressure higher than atmospheric pressure, and solidify as it is. By doing so, volatile metals can also be left in the steel ingot with a good yield.

Furthermore, when pouring LC1, it is also preferable to arrange it so that it can pour into many molds with one operation of the switching valve, and for this purpose, it is preferable to use the branching plate 12 shown in Fig. 1 (6) K. It is valid.

Next, the operation of the device of the present invention will be explained using the first embodiment. First, as shown in Fig. 1(a), pressurized container 11
Increase the internal pressure to 3 atm. At this time, the movable lance 5, which can be moved up and down, is positioned above the molten steel level in the pressurized vessel, and the lance switching valve 6 and the cut-off valve 11 of the additive hopper 7 are kept closed. An additive popper 7 is arranged via a fitting device 13 so as to be able to be installed in a sealed manner above 6.

Ar gas was used as the carrier gas for feeding the additives into the additive hopper 7, and its pressure P2 was set to 7 atm.

Next, as shown in Fig. 1(b), a switching valve 6 and a cutting valve 11 are added to remove [P] and [S] from the molten steel and add metal Ca under pressure. When the processing of molten steel, that is, refining, is completed, the lance 5 rises, the switching valve 6 and the cutoff valve 11 are closed, and the additive hopper 7 and the lance 5 are disconnected by the fitting device 13, and then As shown in C), it is connected to the lance 5 using a fitting device 13 such as a mold 9 so as to be airtightly installed. Next, the mold internal pressure P3 is set to 5 atm, and is lowered together with the lance 5 while being adjusted with the pressure regulating valve 10, and the lance is immersed in the molten steel. Thereafter, the pressure P3 of the mold 9 is lowered to 3 atm by the pressure regulating valve 10, and the pressure P1 inside the pressurized container 1 is reduced to 3 atm.
The molten steel 3 was injected from the ladle 2 into the mold 9 through the lance. A 201 mold was used as the mold, and the molds were poured at once into the molds arranged above the lance from the branching disc 12. How can the pressure difference be used to easily cast the molten steel 3 into the mold 9?
Since it can be solidified under a pressure similar to ATM, there is no rephosphorization or resulfurization during casting, and the yield of volatile metals does not decrease, making it possible to maintain the effects of pressure refining until the time of casting. Can you make high purity steel?

Additionally, a single lance is used to add flux, etc., and during casting, the molten steel is guided into the mold, making the work easier.

CP) by performing refining and casting using the apparatus of the present invention
<: 50 ppm, (S) < 5 ppm steel is easily drawn up into the upper mold due to the pressure difference from the tip of the lance, which is below the slag layer floating at the top. Therefore, it is possible to obtain steel with less slag contamination.

[Brief explanation of the drawing]

1.1 is a diagram showing the pressure refining and casting apparatus of the present invention and its operation. 1: Pressurized container, 2: Ladle, 3: Molten steel, 4: Gas introduction pipe,
5: Lance, 6: Switching valve, 7: Additive hopper, 8: Carrier gas piping m9: fiffLlo: Pressure adjustment valve,
11: Hopper cutoff valve. 】2: Branching board, 13 fitting device. Representative Patent Attorney Masaaki Akizawa 2 Mitsugai July 1981 Patent Application No. 103500 Pressure Refining and Casting Equipment 3 Relation to the Amendment Case Applicant Address (Residence) Tokyo 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (665) Nippon Steel Corporation 4, Agent
Place of residence: 1F, Taiyo Building, Sode 1F, 12-1, Nihonkakukabuto-cho, Chuo-ku, Tokyo Date: Showa Month, Day (Delivery) Rejection J11! Mountain Notification 6: Number of inventions increased by amendment None Contents of Amendment 1: The scope of the claims of this H patent is amended as follows. (1) A pressurized container containing a ladle of molten steel to be cast, a gas introduction device with a pressure adjustment valve to the pressurized container, a movable lance 4 that fits into a hole provided in the outer shell of the pressurized container and can be moved up and down.・Establishment,
Pressure refining and casting equipment, characterized in that it is equipped with a switching valve in the middle of a nuclear lance, and a detachable connection part with an additive injection device or a casting mold with a pressure regulating valve at its upper end. ” 2. Change “Pressure container 11” to “Pressure container 1” at the end of page 5 of the specification.
”. 3. On lines 605 and 605, the words "fitting device" in the fourth line from the bottom of the same page and the third line from the bottom of the same page are respectively changed to "detachable connection part." 4. Shiga, page 8, line 12 (bottom line of the text), "13 Fitting device" is changed to "13: Detachable connection part."

Claims (1)

[Claims] A gas introduction device with a pressure regulating valve, a movable lance that fits into a hole provided in the outer shell of the pressurized container and can move up and down freely, a switching valve in the middle of the lance, an additive injection device and a pressure regulating valve at the upper end. A pressurized refining and casting device characterized by being equipped with a connection part for attaching and detaching a casting mold.