Molten steel scum removing device in vacuum melting

Abstract

The utility model relates to the technical field of vacuum melting high-temperature alloy, and discloses a molten steel scum removing device in vacuum melting, which comprises a vacuum melting furnace, a lifting mechanism, a skimming ladle and a crucible are sequentially arranged in the vacuum melting furnace from top to bottom, the lifting mechanism is positioned at the top of the vacuum melting furnace, and the skimming ladle is positioned at the bottom of the vacuum melting furnace. The lifting mechanism is movably connected with the skimming ladle, a rotating mechanism is further arranged between the lifting mechanism and the skimming ladle, the lifting mechanism, the rotating mechanism, the skimming ladle and the crucible are located on the same axis, and the skimming ladle has a preset inclination angle relative to the surface of molten steel in the crucible. A plurality of through holes are formed in the skimming ladle. According to the utility model, metal oxides, nitrides, sulfides and other inclusions suspended on the surface of molten steel can be effectively removed, the purity of castings and materials is improved, and the production cost is reduced; and the high purity of the high-temperature alloy steel liquid is improved, and a high-quality high-temperature alloy material is obtained.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of vacuum melting high-temperature alloy, especially relates to a floating slag removing device for molten steel in vacuum melting. BACKGROUND

[0002] At present, there are strict requirements for high-purity of high-temperature alloy materials at home and abroad, especially the content control of metal oxides, nitrides and sulfides and other inclusions suspended in high-temperature alloy molten steel is particularly prominent. If these impurities are not removed in time, they will form slag inclusions, pores and other defects in the castings and materials, which seriously affects the strength, toughness and appearance quality of the castings. Pure molten metal can ensure the tightness and flawlessness of the internal structure of the castings, thereby improving the strength, toughness and mechanical properties of the castings.

[0003] Common methods for removing floating slag in molten steel in vacuum melting include: adding slagging agents (such as fluorite, lime and silica sand) and other deslagging and deoxidizing agents: repeatedly adding deslagging and deoxidizing agents to the surface of molten steel and standing for 3-5 minutes to remove slag and deslagging treatment, under the action of deslagging agents, the metal oxides, nitrides and inclusions suspended in the molten steel are removed and carried out. For example, argon is blown into the bottom of the rotating ladle to remove gas and slag: inert gas such as argon is blown into the gas inlet at the bottom of the crucible containing molten steel to remove gas and slag. By floating the free O, N gas and suspended metal oxides, nitrides and sulfides and other inclusions in the inert gas, the purity of the molten steel is improved. However, in the vacuum melting environment, the slag in these two slag removal methods floats on the surface of the molten steel and cannot be removed, which further pollutes the molten steel. In addition, the bottom of the crucible can be cast: the pure molten steel at the bottom of the crucible is cast into the mold through the bottom. However, the slag remaining on the surface of the molten steel will remain in the crucible, and the slag will be removed manually, which has low continuous production efficiency. Or the molten steel is stirred by electromagnetic power frequency to refine and push the slag: the slag is pushed to the crucible wall and the crucible is tilted to hang the slag, which reduces the molten steel slag floating on the liquid surface and reduces the pollution of the castings and materials caused by entering the mold. However, for products with more returned materials, there is more floating slag, and the slag problem cannot be completely solved.

[0004] The above slag removal methods cannot effectively prevent the molten steel from being completely skimmed, so an effective slag skimming device under vacuum environment is needed, and high-temperature alloy materials with higher purity and better performance stability are obtained, which are applied to the fields of automobiles, medical treatment, ships and aerospace. UTILITY MODEL CONTENTS

[0005] The utility model provides a floating slag removing device for molten steel in vacuum melting, which can effectively remove the inclusions in the upper part of the molten steel under the vacuum melting environment, improve the purity of the alloy molten steel, and ultimately reduce the floating slag and improve the performance of the material.

[0006] Technical scheme: the utility model provides a kind of vacuum melting steel liquid dross removal device, comprising: vacuum melting furnace, the furnace of the vacuum melting furnace is equipped with lifting mechanism, skimming ladle and crucible from top to bottom in turn, the lifting mechanism is located the furnace top of the vacuum melting furnace, the lifting mechanism with the skimming ladle is movably connected, the lifting mechanism with the skimming ladle between still be equipped with rotating mechanism, the lifting mechanism, the rotating mechanism, the skimming ladle with the crucible are located same axis, the skimming ladle has preset inclination angle relative to the surface of the steel liquid in the crucible, the skimming ladle has several through holes on it.

[0007] Further, the lifting mechanism includes a reel and a rope matched with the reel; the both ends of the reel are connected with the inner wall of the vacuum melting furnace; the end of the rope is provided with a hook. The reel is arranged in the upper chamber of the vacuum melting furnace, and the lifting of the hook at the end of the rope is realized by winding and unwinding the rope on the reel, so as to finally realize the lifting of the skimming ladle.

[0008] Preferably, the rope is a high-temperature-resistant stainless steel flat ribbon.

[0009] Further, the rotating mechanism includes a transmission device and a rotating shaft arranged below the transmission device. The transmission device provides transmission for the rotating shaft, and specifically includes a worm gear box, one side of the worm gear box is equipped with a high-temperature-resistant vacuum stepping motor drive (direct current 24V), and the inside of the worm gear box is provided with a driving gear connected with the high-temperature-resistant vacuum stepping motor drive and a driven gear connected with the rotating shaft. The driving gear and the driven gear are assembled at a vertical angle, and bearings and bearing seats are matched on the driving gear shaft and the driven gear shaft for transmission of the rotating shaft. The overall transmission speed is controlled at 10-15 r / min. The rotating shaft is made of 316L material, which has high high-temperature-resistant strength.

[0010] Further, the skimming ladle is connected with the rotating shaft through a fastener. The fastener is a bolt, one end of the skimming ladle connected with the rotating shaft has an assembly hole matched with the size of the rotating shaft, the through hole on the assembly hole of the skimming ladle is consistent with the size of the through hole on the assembly hole of the rotating shaft, and the bolt is used to lock them during assembly to prevent them from falling off during use. The skimming ladle is made of mullite powder and a binder by pressing and sintering.

[0011] Further, a counterweight is arranged between the lifting mechanism and the rotating mechanism, the top end of the counterweight is connected with the lifting mechanism through a lifting ring, and the bottom end of the counterweight is connected with the rotating mechanism through a connecting rod. The counterweight is made of 316L stainless steel, and the main purpose of adding the counterweight is to facilitate the device to quickly and smoothly enter the steel liquid when descending, and to ensure the smooth operation of the device when the skimming ladle rotates at low speed.

[0012] Further, the diameter of the skimming ladle is less than the radius of the crucible. The preset diameter of the skimming ladle ensures that the skimming ladle rotates 360° on the surface of the molten steel in the crucible.

[0013] Further, the skimming ladle has an inclination angle of 30-60° relative to the surface of the molten steel in the crucible.

[0014] Further, a high-temperature protection plate is arranged on the rotating shaft between the rotating mechanism and the crucible. The high-temperature protection plate is a 30mm-thick circular stainless steel protection plate (2mm thick), and the inside of the protection plate is a hollow structure filled with aluminum silicate felt high-temperature resistant material, which is used for high-temperature isolation and protection of the driving motor and blocks the heat rising from the molten steel to prevent damage to the vacuum driving motor.

[0015] Beneficial effects: Compared with the prior art, the present application has the following beneficial effects:

[0016] The device has high strength and good heat resistance, is not easy to deform and decompose under the operation of high-temperature alloy molten steel at about 1500℃, can be repeatedly used for multiple times, and reduces production cost. The slag on the skimming ladle can be cleaned and reused for multiple times. The device can effectively remove the inclusions such as metal oxides, nitrides and sulfides suspended on the surface of the molten steel, improve the purity of the castings and materials, reduce production cost, improve the high purity of the high-temperature alloy molten steel, and obtain high-quality high-temperature alloy materials. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a structural diagram of a molten steel floating slag removal device in vacuum melting according to the present application;

[0018] Figure 2 FIG. 2 is a partial structural detail view of the molten steel floating slag removal device in vacuum melting according to the present application;

[0019] Figure 3 FIG. 3 is a schematic diagram of the molten steel liquid level in the crucible before and after use of the molten steel floating slag removal device in vacuum melting according to the present application, wherein (a) is before use, and (b) is after use;

[0020] FIG. 1 is a structural diagram of a molten steel floating slag removal device in vacuum melting according to the present application; DETAILED DESCRIPTION

[0021] The present application will be described in detail below in combination with embodiments.

[0022] Embodiment 1:

[0023] This embodiment provides a device for removing slag from molten steel during vacuum melting, such as... Figures 1-2 The device specifically includes: a vacuum melting furnace 1; inside the vacuum melting furnace 1, a lifting mechanism, a counterweight 8, a rotating mechanism, a slag skimmer 13 and a crucible 14 are arranged from top to bottom, and the lifting mechanism, the counterweight 8, the rotating mechanism, the slag skimmer 13 and the crucible 14 are arranged coaxially.

[0024] The lifting mechanism is located on the top of the vacuum melting furnace 1. The lifting mechanism includes a drum 4, the two ends of which are connected to the inner wall of the upper chamber 2 of the vacuum melting furnace. A winding rope 5 is provided on the drum 4, and a hook 6 is provided at the end of the winding rope 5.

[0025] The top of the counterweight 8 is connected to the hook 6 via the lifting ring 7, and the bottom of the counterweight 8 is connected to the rotating mechanism via the connecting rod 9.

[0026] The rotating mechanism includes a transmission device and a rotating shaft 12 disposed below the transmission device. The transmission device specifically includes a spiral gearbox 10, on one side of which is mounted a high-temperature resistant vacuum stepper motor driver 11 (DC 24V). Inside the spiral gearbox 10 are a driving gear connected to the high-temperature resistant vacuum stepper motor driver 11 and a driven gear connected to the rotating shaft. The driving gear and driven gear are mounted at a perpendicular angle. Bearings and bearing housings are used on the driving gear shaft and driven gear shaft for transmission of the rotating shaft 12. The rotating shaft 12 is made of 316L stainless steel.

[0027] The skimmed ladle 13 is connected to the rotating mechanism via a rotating shaft 12. One end of the skimmed ladle 13 connected to the rotating shaft 12 has an assembly hole that matches the size of the rotating shaft 12. The through hole on the assembly hole of the skimmed ladle 13 is the same size as the through hole on the assembly hole of the rotating shaft 12. During assembly, bolts 18 are used to lock the two together, thus achieving a tight connection between the skimmed ladle 13 and the rotating shaft 12. The slag skimmer 13 is made by mixing and pressing mullite powder and binder, and the diameter of the slag skimmer 13 is smaller than the radius of the crucible 14. The slag skimmer 13 has a 45° tilt angle relative to the surface of the molten steel in the crucible 14, and the slag skimmer 13 has several through holes (Ø5mm). During use, by rotating the slag skimmer multiple times, all the slag on the surface of the molten steel can be removed. The remaining molten steel in the slag skimmer 13 leaks into the crucible 14 through the small holes, while the slag remains in the slag skimmer 13. The refractory material of the slag skimmer 13 has a heat resistance temperature of about 1800℃ and high thermal fatigue strength. The refining temperature of high-temperature alloy metal molten steel is usually 1500℃±50℃, so it can work in high-temperature molten steel for a long time. Each slag skimming operation time is controlled within 2 minutes.

[0028] Optionally, a high-temperature protective plate 16 is also provided on the rotating shaft 12 between the rotating mechanism and the crucible 14. The high-temperature protective plate 16 is a 30mm thick circular stainless steel protective plate (plate thickness 2mm). The interior of the protective plate 16 has a hollow structure and is filled with high-temperature resistant aluminum silicate felt material. It is used for high-temperature isolation and protection of the drive motor, blocking the heat rise from the molten steel and preventing damage to the vacuum drive motor.

[0029] Working principle: In the later stage of alloying in molten steel melting, the counterweight, rotating mechanism, high-temperature protective plate, and skimming ladle of the molten steel slag removal device in vacuum melting are assembled, and the assembled parts are placed on the hook of the drum inside the upper chamber of the vacuum melting furnace. Then, the door of the upper chamber is closed and a vacuum is drawn. When the vacuum level reaches the same level as the melting chamber, the isolation valve between the upper chamber and the melting chamber is opened, and the lifting mechanism of the upper chamber is started. The part below the hook in the device is lowered by the winding rope of the drum. When the skimming ladle enters the crucible to about 10 cm below the molten steel surface, the rotating mechanism is started. A high-temperature resistant vacuum stepper motor (DC 24V) drives a spiral gearbox, which in turn drives a rotating shaft to control the slag skimmer to rotate clockwise on the surface of the molten steel in the crucible at a speed of 10-15 r / min. Through repeated rotations, all the slag on the surface of the molten steel can be removed. The remaining molten steel in the skimmer leaks back into the molten steel through the skimmer's through-hole, while the slag remains inside the skimmer. After skimming, a lifting mechanism raises the skimmer to the upper chamber, and the molten steel and slag inside are removed. If there is a lot of slag on the surface of the molten steel in the crucible, the above operation can be repeated multiple times until the slag on the surface is completely removed. The skimmer can be reused multiple times after cleaning.

[0030] Performance testing:

[0031] Figure 3 The following are schematic diagrams of the molten steel surface in the crucible before and after using the slag removal device for vacuum melting of this utility model: (a) before use; (b) after use; it can be seen that the slag on the surface of the molten steel in the crucible has been significantly removed.

[0032] The O and N values ​​of materials produced by conventional processes and materials produced after removing scum using the device of this invention were tested, and the results are shown in Table 1-2:

[0033]

[0034]

[0035] Conclusion: By comparing Table 1-2, the O and N values ​​of the material produced after removing scum using the device of this invention are lower, indicating that the content of inclusions such as oxides and nitrides is reduced, and the material achieves higher purity.

[0036] The following table shows the test results of removing slag from the surface of molten steel using the device of this invention:

[0037]

[0038] Conclusion: Through this process, the slag grade on the surface of molten steel is less than level 2. This device can effectively improve the purity of molten steel and enhance the quality of materials and castings.

[0039] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent transformations or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A device for removing slag from molten steel during vacuum melting, characterized in that, include: A vacuum melting furnace, wherein a lifting mechanism, a slag skimmer, and a crucible are arranged sequentially from top to bottom inside the furnace. The lifting mechanism is located at the top of the vacuum melting furnace and is movably connected to the slag skimmer. A rotating mechanism is also provided between the lifting mechanism and the slag skimmer. The lifting mechanism, the rotating mechanism, the slag skimmer, and the crucible are located on the same axis. The slag skimmer has a preset tilt angle relative to the surface of the molten steel in the crucible and has several through holes.

2. The slag removal device for molten steel in vacuum melting according to claim 1, characterized in that: The lifting mechanism includes a drum and a rope that is matched with the drum; both ends of the drum are connected to the inner wall of the vacuum melting furnace; and hooks are provided at the ends of the rope.

3. The slag removal device for molten steel in vacuum melting according to claim 1, characterized in that: The rotating mechanism includes a transmission device and a rotating shaft disposed below the transmission device.

4. The slag removal device for molten steel in vacuum melting according to claim 3, characterized in that: The skimming ladle is connected to the rotating shaft by fasteners.

5. The slag removal device for molten steel in vacuum melting according to claim 1, characterized in that: A counterweight is provided between the lifting mechanism and the rotating mechanism. The top of the counterweight is connected to the lifting mechanism via a lifting ring, and the bottom of the counterweight is connected to the rotating mechanism via a connecting rod.

6. The slag removal device for molten steel in vacuum melting according to claim 1, characterized in that: The diameter of the skimming ladle is smaller than the radius of the crucible.

7. The slag removal device for molten steel in vacuum melting according to claim 1, characterized in that: The skimming ladle has an inclination angle of 30-60° relative to the surface of the molten steel in the crucible.

8. The slag removal device for molten steel in vacuum melting according to claim 3, characterized in that: It also includes a high-temperature protective plate, which is disposed on the rotation shaft between the rotating mechanism and the crucible.

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