Metal ripple protection equipment suitable for totally-enclosed electroslag furnace

Abstract

The invention relates to the technical field of metallurgical equipment, and discloses metal corrugated protection equipment suitable for a fully-closed electroslag furnace, which comprises a metal corrugated pipe main body, the metal corrugated pipe main body adopts a 304 corrugated pipe, the metal corrugated pipe main body adopts a double-layer corrugated pipe and three-flange design, the upper layer and the lower layer are made of flexible waves, and the upper layer and the lower layer are made of flexible waves. Meanwhile, upper, middle and lower flanges are designed. According to the metal corrugated protection equipment suitable for the fully-closed electroslag furnace, by arranging the metal corrugated pipe main body and changing the structure and manufacturing materials of the metal corrugated pipe main body, the problems of elasticity losing and fatigue damage of a high-temperature wave plate are solved, the service life of the metal corrugated protection equipment is greatly prolonged, and inconvenience caused by disassembly and replacement is reduced; through the design of the upper flange, the middle flange, the lower flange and the double-layer corrugated pipe, the influence of a metal corrugated pipe body on an equipment weighing system is eliminated, the purpose of constant melting speed is achieved, the equipment is used for all totally-enclosed electroslag furnaces, the totally-enclosed electroslag furnaces are not influenced by air atmosphere, and cast ingots with higher quality can be produced.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical equipment, in particular to a metal corrugated protection device suitable for a fully enclosed electroslag furnace. Background Art

[0002] The electroslag remelting process (ESR) is a main method for producing high-quality ingots. Its advantages include less non-metallic impurities and inclusions in the steel, dense structure, high purity of the ingots, and high metal yield rate. It is widely used in the production of high-quality ingots for the aerospace, energy applications, military and other industries.

[0003] During the electroslag remelting process, the end of the consumable electrode drops to a certain position and connects various parts with the short-mesh wire to form a current loop. Most of the current is converted into heat energy in the slag pool, making the slag pool temperature as high as 1800°C or above. In traditional designs, bellows are usually made of silicone rubber or nylon leather. Due to the influence of high temperature, the wave plate is prone to elastic loss and fatigue damage, and the general service life is 1 to 2 months. In the past, floating seals or flexible joints were mainly used. Whether it is a floating seal or a flexible joint, it will cause an offset in the XY direction. At the same time, the center of the bellows is a conductive rod, which cannot be replaced with an integrated sealing design. Only a zipper structure can be used, so it cannot be completely sealed. Therefore, frequent dismantling and replacement of equipment is required.

[0004] As the molten slag pool is in contact with the air for a long time, harmful gases such as nitrogen, hydrogen, and oxygen in the air dissolve and penetrate into the molten slag pool, which will cause a large number of different types of inclusions and burnout of easily oxidized elements in the steel ingot. Blue brittleness and hydrogen embrittlement may also occur, which will directly affect the fatigue life of the steel ingot, resulting in poor performance of the remelted electric slag steel, unqualified composition, and even brittleness leading to major safety accidents. The high temperature of the consumable electrode intensifies oxidation, and the generated oxides fall into the slag pool with the formed molten droplets, and fully react with the slag pool, resulting in a substantial increase in FeO, which aggravates the easily oxidized elements Al, B, and M in the steel ingot. n and other burnouts, iron powder or aluminum deoxidizers are usually added to the molten slag pool to continuously deoxidize the slag. However, the addition of deoxidizers will change the composition of the slag and fail to meet the ingot production composition standard. It can be seen that a protective cover can be installed on the electroslag furnace crystallizer to isolate the air and pass protective gas to discharge the gas in the electroslag furnace. At the same time, it is necessary to meet the requirements of the protective gas flow rate on the gas flow field in the electroslag furnace, which can not only play a protective role, but also save production costs. Therefore, the study of a metal bellows device suitable for a fully enclosed electroslag furnace is of great significance to the actual application and production of electroslag remelting. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the shortcomings of the prior art, the present invention provides a metal corrugated protection device suitable for a fully enclosed electric slag furnace, which has the advantages of being completely sealed and able to meet long-term use, and solves the problem that iron powder or aluminum-based deoxidizers are usually added to the molten slag pool to continuously deoxidize the slag, but the addition of deoxidizers will change the composition of the slag and fail to meet the composition standards for steel ingot production.

[0007] (II) Technical solution

[0008] In order to achieve the above-mentioned purpose of complete sealing and long-term use, the present invention provides the following technical solutions: a metal bellows protection device suitable for a fully enclosed electroslag furnace, comprising a metal bellows body, the metal bellows body adopts a 304 bellows, the metal bellows body adopts a double-layer bellows and a three-flange design, the upper and lower layers are both made of flexible waves, and three flanges of upper, middle and lower are designed at the same time.

[0009] Preferably, the manufacturing method of the metal bellows body is: using 304 flexible metal bellows, the corrugations are made of soft waves, the additional force is small and the deformation of the weighing sensor can be calculated in microns, so whether there are heavy objects on the weighing platform will not affect the bellows weighing.

[0010] Preferably, the structural design determination method of the metal bellows body is as follows: the bellows adopts a double-layer bellows structure, the lower bellows is used for XY adjustment, and the lateral force is <10kg; the upper bellows is mainly used for weighing, and the external force generated during weighing is ≤1kg.

[0011] Preferably, the lower flange of the three flanges is installed on the fixed platform, the middle flange is installed on the XY adjustment platform, and the upper flange is installed on the weighing upper platform.

[0012] Preferably, the bellows between the middle and lower flanges is adapted to satisfy the movement in the XY directions, and between the upper and middle flanges, it is mainly used for longitudinal deformation for weighing.

[0013] Preferably, the flange weighing base in the bellows is fixed, and when moving in the XY direction (horizontal movement), there is no radial movement between the upper and middle flanges, so when XY is adjusted, it will not affect the weighing of the consumable electrode.

[0014] (III) Beneficial effects

[0015] Compared with the prior art, the present invention provides a metal corrugated protection device suitable for a fully enclosed electroslag furnace, which has the following beneficial effects:

[0016] 1. The metal bellows protection device suitable for fully enclosed electroslag furnaces solves the problems of high-temperature wave plate loss of elasticity and fatigue damage by setting a metal bellows main body and changing the structure and manufacturing materials of the metal bellows main body, greatly improving its service life and reducing the inconvenience caused by removal and replacement. The upper, middle and lower three flanges and double-layer bellows design eliminate the influence of the metal bellows main body on the equipment weighing system, thereby achieving the purpose of constant melting rate.

[0017] 2. This metal corrugation protection device is suitable for fully enclosed electroslag furnaces. The corrugations are made of soft waves, and the deformation of the weighing sensor is calculated at the nanometer level. Therefore, whether there are heavy objects on the weighing platform will not affect the weighing of the bellows. This equipment is used in all fully enclosed electroslag furnaces, and the fully enclosed electroslag furnaces are not affected by the air atmosphere and can produce higher quality ingots. DETAILED DESCRIPTION

[0018] Figure 1 A schematic diagram of oxygen content in the consumable electrode of the present invention;

[0019] Figure 2 This is a schematic diagram of the element composition of the rack steel of the present invention;

[0020] Figure 3 This is a schematic diagram of detecting the hydrogen and oxygen content in a sample according to the present invention;

[0021] Figure 4 Schematic diagram of the relationship between oxygen content and time in steel tested in a fully enclosed and conventional electroslag furnace according to the present invention;

[0022] Figure 5 It is a schematic diagram of the change of oxygen content in the steel with time under the constant temperature condition of 1800°C for the experimental steel of the present invention;

[0023] Figure 6 It is a schematic diagram of oxygen content in the electric slag furnace of the present invention;

[0024] Figure 7 It is a schematic diagram of the composition of the head, middle and tail parts of the steel ingot of the present invention;

[0025] Figure 8 Schematic diagram of the N, H and O contents of the electroslag ingot of the present invention.

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1:

[0028] Company A smelted five batches of a steel base material of the same furnace number in different electroslag furnaces. 1#, 2#, 3#, 4#, and 5# represent the sample numbers respectively. 1# and 2# were smelted in conventional electroslag furnaces, while 3#, 4#, and 5# were smelted in metal bellows protective covers.

[0029] According to the analysis of nitrogen and oxygen meter, the initial oxygen content of consumable electrode is 10×10-6ppm, the average oxygen content of ingots produced by 1# and 2# conventional electroslag furnaces is 30.2×10-6ppm, and the average oxygen content of ingots produced by 3#, 4#, 5# and 6# fully enclosed electroslag furnaces using metal bellows protection cover is 18×10-6ppm, which is significantly reduced. Figure 1 shown.

[0030] Oxygen in the atmosphere penetrates into the slag pool and is transferred to the steel. It can be seen that under the protection of the metal bellows protective cover, the increase in oxygen content in the atmosphere during the electroslag remelting process is effectively controlled.

[0031] Embodiment 2:

[0032] Rack steel was used as the test steel type, and the chemical composition of its electroslag blank was as follows: Figure 2 As shown, firstly, 10 specimens with a diameter of 50 mm and a height of 50 mm were cut out of the rack steel, and the surface oxide scale was removed by grinding and polishing. Then, the slag was baked to remove its moisture. Five groups of experiments were designed respectively.

[0033] In a closed electroslag furnace using a metal bellows protective cover, samples are taken at a constant temperature of 1800°C for 1h, 2h, 3h, 4h, 5h, 6h, 7h, and 8h. After drying, the hydrogen and oxygen content in the samples is tested. The content is as follows: Figure 3 .

[0034] like Figure 5 The graph shows the change of oxygen content in the steel with time under the constant temperature condition of 1800℃. The initial oxygen content of the experimental steel in the fully enclosed electroslag furnace was 120×10-6ppm, which dropped to 35×10-6ppm after 2h of constant temperature and reached 56×10-6ppm after 8h of constant temperature. However, the oxygen content of the experimental steel in the conventional electroslag furnace without a protective cover increased significantly. It can be concluded that the sealing performance of the equipment is excellent, and the use of a fully enclosed metal bellows to introduce a protective atmosphere during electroslag remelting will effectively reduce the oxygen content of the steel ingot.

[0035] like Figure 5The curve shown is the change of hydrogen content in the experimental steel with time under the constant temperature condition of 1800℃. The initial hydrogen content of the experimental steel in the fully closed electroslag furnace was 3.0×10-6ppm, which dropped to 3.5×10-6ppm after 2h of constant temperature and reached 2.4×10-6ppm after 8h of constant temperature. The hydrogen content of the experimental steel in the conventional electroslag furnace without a protective cover has been on an upward trend, increasing from an initial hydrogen content of 1.8×10-6 to 8.7×10-6ppm.

[0036] It shows that the hydrogen content of the steel ingot in the electroslag furnace without the metal bellows increases significantly during the electroslag remelting process. Due to the good sealing performance of the metal bellows, the protective cover allows the introduction of protective gas to effectively reduce the hydrogen content in the steel ingot.

[0037] Embodiment three:

[0038] In order to verify the tightness of the metal bellows equipment, an oxygen analyzer was used in a certain enterprise to record the changes in oxygen content in the electroslag furnace during the actual production process. Figure 6 As shown, the oxygen content in the initial state is about 21.2%, the electroslag remelting furnace starts to operate, and protective gas is continuously introduced into the fully enclosed metal bellows protective cover. After smelting for 0.5h, the oxygen content in the electroslag furnace drops to about 10.2%, and the oxygen content drops sharply; after smelting for 1h, the oxygen content in the electroslag furnace drops to about 8.5%; after smelting for 4h, the oxygen content in the electroslag furnace is about 2.8%; after smelting in the electroslag furnace for 8h, the oxygen analyzer data no longer changes, and the gas equilibrium state is reached in the electroslag furnace. At this time, the oxygen content is about 0.5%. As shown in the figure, the use of the metal bellows protective cover can effectively reduce the oxygen content in the electroslag furnace, providing good conditions for the production of high-quality ingots.

[0039] Experimental Example 4:

[0040] To verify the feasibility of the present invention, three sections of the head, middle and tail of the rack steel ingot were randomly selected from 100 furnaces smelted on site for component analysis. The analysis results are shown in Figure 7 , it can be seen that the composition of the head, middle and tail of the ingot does not fluctuate much, indicating that the composition uniformity of the ML40CR ingot is good.

[0041] The beneficial effects of the present invention are as follows: the metal bellows protection device suitable for a fully enclosed electric slag furnace solves the problems of elastic loss and fatigue damage of high-temperature wave plates by setting a metal bellows main body and changing the structure and manufacturing materials of the metal bellows main body, thereby greatly improving its service life and reducing the inconvenience caused by dismantling and replacement. The upper, middle and lower three flanges and double-layer bellows design eliminate the influence of the metal bellows main body on the equipment weighing system, thereby achieving the purpose of constant melting rate.

[0042] In addition, the corrugation is made of soft waves, and the deformation of the weighing sensor is calculated at the nanometer level. Therefore, whether there are heavy objects on the weighing platform will not affect the weighing of the bellows. The equipment is used in all fully enclosed electroslag furnaces, and the fully enclosed electroslag furnaces are not affected by the air atmosphere and can produce higher quality ingots.

[0043] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A metal corrugated protection device suitable for a fully enclosed electroslag furnace, comprising a metal corrugated pipe body, It is characterized in that The main body of the metal bellows is a 304 bellows. The main body of the metal bellows is a double-layer bellows and a three-flange design. The upper and lower layers are both made of flexible waves, and three flanges are designed, upper, middle and lower.

2. A metal corrugated protection device suitable for a fully enclosed electroslag furnace according to claim 1, It is characterized in that The manufacturing method of the metal bellows body is as follows: a 304 flexible metal bellows is used, the bellows are made of soft waves, the additional force is small and the deformation of the weighing sensor can be calculated in microns, so whether there is a heavy object on the weighing platform will not affect the bellows weighing.

3. The metal corrugated protection device suitable for a fully enclosed electroslag furnace according to claim 1, It is characterized in that The structural design determination method of the metal bellows body is as follows: the bellows adopts a double-layer bellows structure, the lower bellows is used for XY adjustment, the lateral force is less than 10kg, and the upper bellows is mainly used for weighing, and the external force generated during weighing is ≤1kg.

4. The metal corrugated protection device suitable for a fully enclosed electroslag furnace according to claim 1, It is characterized in that The lower flange of the three flanges is installed on the fixed platform, the middle flange is installed on the XY adjustment platform, and the upper flange is installed on the weighing upper platform.

5. The metal corrugated protection device suitable for a fully enclosed electroslag furnace according to claim 4, It is characterized in that The bellows between the middle and lower flanges is adapted to meet the requirements of movement in the XY directions, and between the upper and middle flanges, it is mainly used for longitudinal deformation for weighing.

6. A metal corrugated protection device suitable for a fully enclosed electroslag furnace according to claim 5, It is characterized in that The flange weighing base in the bellows is fixed. When moving in the XY direction (horizontal movement), there is no radial movement between the upper and middle flanges. Therefore, when XY is adjusted, it will not affect the weighing of the consumable electrode.

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