JPS6217117A - Molten steel treatment device - Google Patents

Abstract

PURPOSE:To permit the common use of the working spaces for a vacuum degassing device and powder injection device by disposing a horizontal rail above a ladle and providing carriages for vacuum degassing and carriage for powder injection in common use for inert gas bubbling in such a manner that these carriages can respectively independently move on the rail. CONSTITUTION:The ladle 1 contg. a molten steel 9 is carried over a ladle lifting device 2. The rail 11 extending in a horizontal direction is installed above the ladle 1. The carriages 4a, 4b for vacuum degasssing and the carriage 12 for powder injection in common use for inert gas bubbling are made respectively independently movable on the rail 11. The working space used for vacuum degassing and the working space for executing the powder injection are thus made commonly usable and the operations of the vacuum degassing and powder injection are selectively executed.

Description

[Detailed Description of the Invention] [Industrial Field of Application J] The present invention relates to a ladle that is used to process molten steel tapped from a melting furnace (including a converter, etc., hereinafter the same) before sending it to an ingot making process such as continuous casting. Regarding equipment for internal molten steel processing, in detail, molten steel processing can be performed in a continuous combination of stirring by inert gas injection or powder injection processing and vacuum degassing processing! This is related to aii.

[Prior art] Before molten steel produced in a converter, electric furnace, etc. is made into an ingot using a continuous casting device or a large mold, it is necessary to (a) equalize and optimize the temperature of the molten steel in the ladle, and (b) Cleaning of molten steel, (c)
The molten steel undergoes various treatments in a ladle for the purpose of adjusting the molten steel composition.

Methods for treating steel in a bubble ladle include the bubbling method, in which inert gas such as Ar gas is blown into the molten steel in the ladle through a bottom blow hole or lance, and the vacuum degassing method, in which the molten steel is sucked up into a vacuum chamber and brought into contact with the vacuum section. The law is mainly used.

As an example, a vacuum degassing device using the RH method is shown in Figure 3 (a).
This is shown and explained below. #The molten steel transferred from the cracking furnace to the ladle 1 is placed on the trolley 14 and transported to the lower part of the vacuum degassing device. Two vacuum chambers 3a and 3b for sucking up molten steel and making it contact with the vacuum section are arranged on degassing carts 4a and 4b, respectively, and the degassing carts 4a and 4b move along a track 11 in the left-right direction in the drawing. It is placed so that it can be moved horizontally.

The reason why two vacuum chambers for degassing are used is that one vacuum chamber is prepared as a spare, and molten steel is processed continuously even while the other vacuum chamber is being inspected and repaired using the repair trolley 5. This is to ensure that.

There is a duct 1 in the vacuum chamber 3a placed directly above the duct 1.
Scale fi4 through 5! i6 and an alloy metal tank 7 are provided, and alloy metals necessary for adjusting the composition of molten steel are blended through the weigher 6 and added to and mixed with the molten steel drawn up into the vacuum tank 3a. A lifting device 2 is provided below the vacuum chamber 3a for raising and lowering the ladle 1 that has been moved toward or away from the vacuum chamber 3a. R.H.
In the vacuum chamber of the method, Ar gas is blown into one of the two immersion tubes 8 as shown in Fig. 3(b), and the molten steel 9 is raised into the vacuum chamber 3 using the principle of a gas lift pump. The gas components in the molten steel are removed by contacting the molten steel with the vacuum section of the molten steel. However, there are various degassing methods such as the DH method, and the present invention is not particularly limited thereto.

[Problems to be solved by the invention] When trying to obtain special steel such as ultra-low sulfur steel or low oxide steel,
It cannot be said that desulfurization and deoxidation are sufficiently achieved by vacuum descaling such as the DH method or the RH method, and as a means of refining these special steels, alkaline earth metal-based chemicals are mixed with a carrier gas in a ladle. A so-called powder injection method, in which powder is injected into molten steel, is sometimes used in combination.

As a powder injection device, a device using a ladle bottom blower 4 or an immersion lance is used.Generally, an Ar bubbling device is installed just before continuous casting and conveying to a dollar trolley to inject Ca-5i and Fuller 2x such as CaO type is injected.

However, if a device for both injection of alkaline earth metal-based substances into molten steel and Ar bubbling (hereinafter also simply referred to as an injection device) is installed on a one-dollar turret, it becomes difficult to use the injection device. Due to the fact that special steel is rarely smelted, it has become extremely uneconomical in terms of space, and it has been found that it is very inconvenient to use it interchangeably with vacuum degassing equipment, which is highly versatile.

Therefore, the present inventors have devised a method for efficiently processing molten steel, whether vacuum degassing of molten steel and powder injection are performed alone or in combination.
Moreover, we believed that it was necessary to devise an economical arrangement that would prevent equipment and equipment from being wasted, and after conducting various researches, we finally completed the present invention.

[Means for Solving the Problems] The present invention is an apparatus for processing molten steel in a ladle, in which a horizontal track is disposed above the ladle, and a vacuum degassing trolley and an inert gas bubbling and powder processing apparatus are provided. The gist lies in that the injection carts are placed movably independently on the track.

[Function] When processing the molten steel in the ladle in parallel between the melting furnace and the continuous casting device, the vacuum degassing trolley and the powder injection trolley can be moved independently on the same horizontal track. By arranging it in a similar manner, the work space used for vacuum degassing and the work space for powder injection can be shared, and both vacuum degassing and powder injection operations can be switched and carried out efficiently. It was decided that In other words, the conditions can be freely set, whether vacuum degassing treatment or powder injection treatment is performed individually, or whether the vacuum degassing treatment is followed by powder injection treatment or vice versa. In response to the demand for manufacturing a variety of steel types, molten steel processing can be carried out without waste.

Furthermore, according to the present invention, common equipment (for example, a weighing machine, etc.) can be used in both the vacuum degassing equipment and the powder injection equipment, so it is possible to reduce the space occupied by the equipment in the factory and the equipment cost.

[Example] A typical embodiment of the invention is shown in FIG.

A ladle l containing molten steel 9 is carried from the melting furnace onto the ladle lifting device 2. The lifting device 2 raises and lowers the ladle 1 to approach or leave the molten steel processing device. A track 11 extending horizontally is installed above the ladle 1,
Two vacuum descaling carts (hereinafter simply referred to as degassing carts) 4a and 4b and a powder injection and inert gas bubbling cart (hereinafter referred to as powder injection carts) are placed on the track ll. . Repair carts 5.5 for maintaining and repairing the vacuum degassing tanks 3a and 3b are provided at the lower left and right sides of the track 11.

Further to the L side of the degassing carts 4a, 4b or the powder injection cart, a metal tank 7 for alloy is provided, and an appropriate amount of the additive substance stored in this tank is prepared using a weighing device 6, and then transferred to a rotary feeder 10. A substance addition device for supplying the substance into the molten steel through the duct 15 is also provided.

In Fig. 1, the powder injection cart 12 is shown disposed directly above the ladle l, but in Fig. 2, the powder injection cart 12 is used to perform powder injection. represents the state. Next, the structure of the powder injection trolley will be schematically explained. A lift truck 14 is attached to the frame 16 of the powder injection truck 12.
Injection lance 1 so that it can be raised and lowered freely by
3 is disposed, and at the same time as the ladle 1 is raised by a lifting device 2 (not shown in FIG. 2), the injection lance 13 is lowered and immersed in the molten steel 9. The injection lance 13 is constructed of a cylindrical body, and additive substances are fed into the lance using an inert gas such as Ar scum as a carrier gas to refine the molten steel. Ar gas, which is a carrier gas, is fed from the carrier gas introduction path 15 to the injection lance 13 via a hose 17, etc., and upper alkaline substances such as Ca-5i and CaO are fed into the carrier gas from the pressure regulating tank 6a. The mixed powder is mixed with powder and sent to the injection lance 13.

The process of molten steel treatment is divided into the following steps.

That is, during normal operation, two vacuum chambers 3a are prepared.
, 3b, vacuum degassing is performed while adding an alloying metal or a sticky material such as flux, and then the next step is performed. When special treatment is required to manufacture ultra-low sulfur steel, etc., vacuum degassing is performed using one of the vacuum chambers 3a and 3b as described above, and then the powder injection cart 12 is used to perform vacuum degassing. Ca-3i and CaO-based fluxes are injected to perform more effective deoxidation and desulfurization. In this case, the same effect as described above can be obtained even if the order of the vacuum degassing operation and the powder injection operation is reversed. Alternatively, if both of the two vacuum chambers 3a and 3b are out of order or both need to be overhauled,
The molten steel may be treated by stirring the molten steel by performing Ar bubbling while adding an alloying metal or a sticky material using the powder injection cart 12.

[Effects of the Invention] By using the apparatus of the present invention, molten steel processing carried out in a ladle can be performed in various ways, including degassing in a vacuum tank, degassing in a vacuum chamber, degassing in Ar bubbling, and degassing and stirring/injection in powder injection. It became possible to implement it. Furthermore, since the vacuum degassing truck and the powder injection truck are arranged on the same track, the space of the entire device can be kept small and the equipment cost can be kept low.

[Brief explanation of the drawing]

FIG. 1 is an elevational view showing a typical embodiment of the invention; FIG.
The figure is an explanatory diagram showing a state in which molten steel is processed in a ladle using an Ar bubbling trolley, Figure 3 (a) is an elevational view showing an example of a device used for conventional RH method vacuum degassing, b) is an explanatory diagram showing vacuum degassing by the RH method. l... Ladle 2... Lifting device 3a,
3b... Vacuum chambers 4a, 4b... Vacuum degassing trolley 5... Repair trolley 6... Weighing machine 8a... Pressure regulating tank? , 7a... Alloy metal tank 8... Immersion tube 9... Molten steel lO... Rotary feeder 11... Track 12... Ar bubbling trolley l3... Injection lance 14... Lifting cart 15... Carrier gas introduction path 16... Frame 17... Hose Figure 2 Figure 1 Figure 3b Figure 3 (a) Figure 3 (b)

Claims (1)

[Claims] A device for processing molten steel in a ladle, in which a horizontal track is arranged above the ladle, and a vacuum degassing trolley and an inert gas bubbling/powder injection trolley run independently on the track. A molten steel processing apparatus characterized in that the molten steel processing apparatus is movably mounted on the molten steel.