JPH04503533A - Method and apparatus for vacuum treating metals - 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] name of invention Methods and equipment for vacuum treating metals Technical field The present invention is based on the example described in the generic concept of one of claims 1 to 3. The present invention relates to a method and apparatus for vacuum treating metals such as steel.

Background technology In ladle degassing, a ladle filled with molten steel is lowered into a cylindrical chamber. The cylindrical chamber is then vacuum-tightly closed with a lid. As a sealing member, it is usually A rubber ring is used. The lid is manufactured from steel casting or sheet metal construction. Underside of the lid A radiation protection member consisting of a pressed metal plate and/or refractory material is provided. ing. A dosing device and an observation window are provided on the lid.

A vacuum generator usually consists of at least four steam injectors. Negative pressure is applied to molten steel. The interior of the molten steel has a pressure that depends on the internal pressure above the molten metal surface. There are gas bubbles. Molten steel with high oxygen content and not stationary should be vacuum treated. Carbon oxide is formed when the pressure in the free space of the container drops below 300 Torr. boiling, which removes hydrogen and nitrogen from the molten metal and thus Gas removal takes place even in a relatively poor vacuum. If the pressure is further lowered, boiling will occur. , for example, so violently that the molten steel rises 1 m or more in the ladle. . In order to make the inner wall of the ladle sufficiently high, select a somewhat large ladle and provide extra height. It is necessary to prevent molten steel from reaching the edge of the ladle, but current steel mills Then the ladle size and filling weight are matched to the lifting device. Must have sufficient margin Because of this, it is not possible to fill the ladle to the edge, resulting in low productivity. make the ladle bigger An alternative solution is to adjust the lifting and storage equipment to accommodate the increased transport weight. must match.

In another solution, a receiving container is provided that relies on a ladle. German patent issued From Application Publication No. 2032830, it is known that the open side of the immersed body is in the molten metal to the deepest part. Immersion bodies are known which are immersed in water and then evacuated inside the body. This immersion The immersion body is pushed into the molten metal to obtain the required immersion depth during vacuum processing. It has disadvantages that must be overcome. When negative pressure is applied, the surface of the molten metal will change due to the pressure difference. and may have a height of significantly more than 1 m. In contrast to this The molten metal surface, to which no vacuum is applied, will fall by an equivalent amount. compared to a ladle By housing the molten metal in a small immersion body, a relatively large amount of molten metal can be , is separated from the molten metal remaining in the ladle and is therefore separated into two molten metal parts. There is a drawback that a vacuum is applied.

From German Patent Application No. 1965136, there is a A ladle filled with molten metal that allows the attached reaction tube to be immersed in molten metal. Devices for degassing are known. A lance with active gas is used for metallurgical processing. For this purpose, the gas is guided into a chamber surrounded by reaction tubes, and degassing and This results in an increase in the volume of the molten metal. The same negative pressure is applied to the molten metal surface. This ensures that the increase in volume within the ring area between the reaction tube and the ladle edge is cannot be avoided.

German Patent Application No. 1912907 or German Patent Application No. 1919 From Publication No. 053, gas is separated from the molten metal by a tubular separation wall immersed in the molten metal. Devices introduced therein are known. This separation wall is formed into a ring by another tubular separation wall. The cylindrical chamber and ring-shaped chamber formed by these separation walls are connected to each other. It's flowing. Connection to pressure pump and/or suction pump allows for different pressures The height of the molten metal surface in the individual chambers can be adjusted differently for the molten metal flow is improved.

technical challenges The object of the present invention is to provide a simple method that does not require extra height of the ladle and does not prevent degassing of molten metal. A method for removing the above-mentioned defects using suitable means, for example, for vacuum treating metals such as steel. The objective is to provide methods and equipment.

The above problem is solved by the features described in the characteristic parts of claims 11 to 3. Ruya In the present invention, the vacuum processing container is structurally simple, relatively small, and lightweight. An apron is attached. The diameter of this apron depends on the immersion depth of the apron. It is slightly smaller than the diameter of the ladle. , the lower open edge of the L prong is made of molten metal. There are two melts due to the apron being immersed, which is slightly immersed in the Metal surface sector, i.e. ring-shaped molten metal surface (lid and circular molten metal surface sector) A sector is formed, and different negative pressures are applied to the two sectors.

Differential pressure can be adjusted arbitrarily. The preferred area is 2 to 2” of one pressure stage. between the pressure stages.

A screen with a radius in the ratio of 8:1 to 122:1 to the width of the ring-shaped sector The size of the tube does not impede the vacuum processing of all molten metal; this effect is , the immersion depth of the apron is limited to a minimum of 10 to 20 (1 will be improved. The above spatial dimensions and the shallow immersion depth of the apron facilitate the flow of molten metal. There is little to no interference. This allows the cleaning gas to pass through up to three cleaning gas nozzles. This condensation occurs because the molten metal flow rate is usually high at present. It has a particularly advantageous effect.

This effect depends on the filling height of the ladle, as the screen is formed vertically adjustable. If the immersion depth of the apron can be adjusted in each phase of the vacuum process, It becomes impossible to increase it.

The pressure difference can be tapped off directly between the two pressure stages or by providing a branch pipe with a throttle valve. It can be adjusted by

Next, the present invention will be explained in detail based on an embodiment using figures.

Figure 1 shows the vacuum processing equipment with the metal lid when connected from different stages of the vacuum generator. Figure 1a is a cross-sectional view similar to Figure 1 with a possible apron in the axial direction. It is a front view. Figure 2 is a cross-sectional view of a vacuum processing container with an axially movable apron; Figure 3 shows the connection of the vacuum processing equipment to the vacuum generating station run through the branch pipe and throttle valve. FIG. 3 is a cross-sectional view of the connection.

BEST EMBODIMENT OF THE INVENTION 1 and 1a show a vacuum processing vessel 30 having a flange and a sealing ring. However, M2O is placed on top of the vacuum processing container 30. Inside the vacuum processing container 30 A ladle 40 is provided which is filled with molten metal 41.

The lower edge 21 of the apron 21 fixed to the lid 20 is submerged in the molten metal. ing.

The apron 21 submerged below the molten metal surface in the ladle circles the molten metal surface. It is divided into a shaped segment 42 and a ring shaped segment 43.

Circular molten metal surface 42, inner mantle of apron 21 and circular portion 23 of lI 20 Free space A is surrounded by .

Other parts of the lid 20, including the ring-shaped part 29, the outer side of the mantle of the apron 21 surface, the lower part of the vacuum processing container 30, the outer side of the ladle 40, and the ring-shaped molten metal surface 43 surrounds the free space B.

Observation windows 33.34 are provided in the lid 20 to observe the molten metal 42.43. It is. The free space A is connected via the connecting pipe 24 in the area of the circular part 23 and The free space B is connected to the vacuum device IO via a connecting pipe 25 in the area of the ring-shaped lid part 29. It is being continued.

Vacuum generator! 10 is a water seal pump 14, a steam injector 13 (60 Torr), a water seal A condenser 16 and a steam injector 12 provided between the pump 14 and the steam injector 13 (10 Torr), steam injector 11 (0,5 Torr), and injector 12 The condenser 15 installed between and 13 is installed. Free space A is steam injector 1 1 maximum negative pressure stage p1, and the free space B is injected in this example by two stages less. It is connected to a negative pressure source between vessels 13 and 12. Vacuum generator 10 is operating During this period, the level of the circular molten metal surface 42 becomes the level of the ring-shaped molten metal surface 43. Compared to (!a), it rises higher.

In addition to the above-described device of FIG. 1, FIG. It protrudes into the free space A through the electrode guide hole in the region 3.

FIG. 2 schematically shows an apron 21 which is vertically adjustable. The prong 21 is fixed to a circular portion 23 on the lid 20, and the circular portion 23 is attached to the lid 20. The position of the ring-shaped portion 29 can be adjusted by the adjustment member 51.

A compensator 53 is provided between the ring-shaped portion 29 and the circular portion 23 for gas-tight sealing. It is provided. The connecting pipe 25 to the free space B is provided in the lid 20 in one example. In the other example, it is provided in the lower part of the vacuum processing container 30.

Although FIG. 3 shows all the important parts of FIG. 1, the connection pipe 24 to free space A is shown in FIG. The connection is made via a branch pipe 26, which also connects to the connection pipe 25 in free space B. The difference is that a throttle valve 27 is provided between the branch pipe 26 and the connecting pipe 27. Ru.

Reference number list ■ Central axis 10 Vacuum device 22 Edge area 24.25 Connecting pipe 26 Branch pipe 28 Ring-shaped opening 29 M ring-shaped part 30 Vacuum processing container 40 Ladle 41 Molten metal 42 Circular molten metal surface A, B free space 5111 Adjustable parts 60 electrode Submission of translation of written amendment August 21, 1991

Claims (7)

[Claims] 1. The molten metal is in a vacuum processing vessel that is tightly closed by a lid; The surface of the metal is separated into circular sectors and ring-shaped sectors, and the surface of the molten metal is For example, for vacuum processing molten metals such as steel, where different negative pressures are applied during vacuum processing. In the second method, the ring-shaped sector exerts less negative pressure than the circular sector. and the separation into sectors is due to the depth of immersion into the molten metal in the ring-shaped sectors. For vacuum processing of molten metal characterized by being carried out to a depth of 10-20 cm. Method. 2. The negative pressure difference between the ring-shaped sector and the circular sector causes one pressure stage of the vacuum device to Claims characterized in that they are selected to correspond to at least 1/2. A method for vacuum treating molten metal according to paragraph 1. 3. A valve having a lid equipped with a sealing member and connected to a multi-stage vacuum generator. Equipped with an empty processing container, the ladle filled with molten metal is placed in the vacuum processing container. A device for carrying out the method according to claim 1 or 2 that can be attached. In the position, the lid (20) is arranged parallel to the central axis (1) of the lid (20). an edge area (22) of the apron (21); protrudes into the molten metal (41) in the ladle (40), and the diameter of the apron (21) , slightly smaller than the diameter of the ladle at the immersion depth in the edge region (22). and the connecting pipes (24, 25) connected to the vacuum device (10) are The circular part (23) in the lid (20) and the filled state are separated by the long tube (21). a free space surrounded by a circular molten metal surface (42) in the ladle (40); (A), the ring-shaped part (29) in the lid (20), the vacuum processing container ( 30), a ladle (40), and a ring-shaped molten metal surface (4) in the filled ladle. 3) is provided for the free space (B) surrounded by The connecting pipe (24) of the injector (24) with the highest pressure stage in the vacuum device (10) 11) and a connecting pipe (25) to the free space (B) is connected to the vacuum device (10). A device characterized in that it is connected to the highest pressure stage at the second stage in the second stage. 4. A branch pipe (25) having a throttle member (27) connected to the free space (A) 26) is connected and the branch pipe (26) is connected to the free space (B). 4. The device according to claim 3, characterized in that 5. The lid (20) has a ring-shaped opening (28), and the adjustment member (51) The apron (21) is aligned with the central axis (1) by the adjustment member (51) provided on the lid (20). 4. Device according to claim 3, characterized in that it is movable in parallel to ). 6. A ring-shaped part (29) in the lid (20) and in the apron (21), A compensator (53) is placed in a gas-tight manner between the edge (23) facing away from the ladle (40). 6. Device according to claim 5, characterized in that it is fixed to. 7. At least one electrode (60) can be guided through the lid (20) The method according to one of claims 3 to 6, characterized in that Device.