Electroslag remelting method of high alloy material
By optimizing the melting rate and electrode design in stages during the electroslag remelting process, the problems of low electroslag remelting efficiency and electroslag ingot quality were solved, and efficient and low-energy-consumption electroslag ingot production was achieved.
Patent Information
- Application Number
- CN202511822950.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-05
- Publication Date
- 2026-03-03
Smart Images
Figure CN121592869A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electroslag remelting technology, and more specifically, to a method for electroslag remelting high alloy materials. Background Technology
[0002] Electroslag remelting, as a special metallurgical technology, is mainly used in the field of high alloy materials, including the production of high-end metal materials such as tool and die steel, corrosion-resistant alloys, high-temperature alloys, and special stainless steel.
[0003] Currently, the electroslag remelting process generally includes arc initiation and slag formation, remelting, feeding, and electroslag ingot demolding. Each stage of the existing electroslag remelting process has some problems that urgently need to be solved, as follows: (1) In general, in order to obtain electroslag ingots with high longitudinal solidification consistency, the ratio of melting rate to crystallizer diameter in the remelting stage is generally less than 1.0. The setting of this melting rate lacks fine division of the remelting stage, which may affect the remelting efficiency and lead to an increase in the electrical energy consumed by electroslag remelting.
[0004] (2) In the arc initiation and slag formation stage, consumable electrodes or graphite electrodes are generally used for arc initiation. However, both types of electrodes have their own defects. Specifically, when consumable electrodes are used for solid slag initiation and slag formation, the melting of the consumable electrode accompanies the slag formation process due to the low melting point of high alloy materials, resulting in poor quality of the lower part of the electroslag ingot. On the other hand, when graphite electrodes are used for early slag formation, it is easy to cause carbon accumulation at the bottom of the electroslag ingot. More importantly, the slag system often contains CaO, which increases the risk of hydrogen accumulation at the bottom of the electroslag ingot, especially when the air humidity increases. Summary of the Invention
[0005] 1. Technical problems to be solved This invention provides an electroslag remelting method for high-alloy materials. This method finely divides the remelting stages of electroslag remelting, providing corresponding distinguishing points to separate a rapid remelting stage and a stable remelting stage, and offering corresponding melting rate designs. While ensuring the uniformity of the electroslag solidification structure, the melting rate of the rapid remelting stage is further increased, thereby improving the remelting efficiency of this stage and reducing the electrical energy consumed in electroslag remelting. Furthermore, the slag-forming electrode used in the arc-initiation and slag-forming stage is optimized to ensure sufficient melting of the slag material while preventing the slag-forming electrode from melting, and to reduce the gas content in the slag material, thus solving the problem of hydrogen accumulation at the bottom of the electroslag ingot.
[0006] 2. Technical solutions adopted To achieve the above objectives, the technical solution provided by the present invention is as follows: This invention provides an electroslag remelting method for high-alloy materials, including a remelting stage comprising a rapid remelting stage and a stable remelting stage. Specifically: when the height of the remelted ingot inside the crystallizer is less than the diameter of the crystallizer, it is a rapid remelting stage. In this stage, the melting rate first gradually increases to a first melting rate, and then maintains this melting rate to continue remelting. The ratio of the first melting rate to the crystallizer diameter is 1.3, the unit of the first melting rate is kg / h, and the unit of the crystallizer diameter is mm. When the height of the remelted ingot inside the crystallizer is equal to the crystallizer diameter, the process transitions from the rapid remelting stage to the stable remelting stage. In the initial stage of the stable remelting stage, the melting rate gradually decreases from the first melting rate to a second melting rate, and then maintains this second melting rate until the end of the stable remelting stage.
[0007] It should be noted that during the formation of the remelted ingot, the ratio of the first melting rate to the crystallizer diameter (hereinafter referred to as the melting rate ratio) generally does not exceed 1.0, where the unit of the first melting rate is kg / h and the unit of the crystallizer diameter is mm. While a lower melting rate ratio helps improve the solidification quality of the corresponding height section of the remelted ingot, the overall performance evaluation of the resulting remelted ingot needs to comprehensively consider its weakest area along the longitudinal direction. The inventors inadvertently discovered that in the initial stage of remelting, i.e., the rapid remelting stage as referred to in this invention, further increasing the melting rate of the rapid remelting stage, i.e., increasing the value of the first melting rate, can still ensure that the solidification quality of that section of the resulting remelted ingot meets the overall performance requirements. The reason for this is that in the initial stage of remelting, under the combined cooling of the bottom water tank and the crystallizer, further increasing the melting rate allows the molten pool inside the crystallizer to remain shallow and flat, which maintains good solidification quality. Through in-depth research into the remelting process, the inventors determined that the ratio of the first melting rate to the crystallizer diameter is 1.3, and also identified the endpoint of the rapid remelting stage, which is the starting point of the stable remelting stage. In summary, by increasing the value of the first melting rate, the efficiency of electroslag remelting is further improved while reducing energy consumption, ensuring good solidification quality of the remelted ingot.
[0008] During the rapid remelting phase Figure 1 The figure shows a simulation of the molten pool temperature distribution when the melting rate ratio is 1.3. The red portion represents the liquid state, the blue portion represents the solid state, and the boundary between the red and blue portions is the solid-liquid mixing zone. The horizontal axis represents the radius of the crystallizer, the vertical axis represents the height of the crystallizer, and the depth of the molten pool is represented by h. Generally, an ideal molten pool depth is 1 / 3 to 1 / 2 of the crystallizer diameter. The simulation shows that the ratio of h to the crystallizer diameter satisfies this requirement, meaning that the cooling performance of the bottom water tank and the crystallizer can meet the melting rate requirements to maintain the shallow and flat shape of the molten pool.
[0009] Furthermore, in the initial stage of the stable remelting phase, the melting rate is gradually reduced from the first melting rate to the second melting rate within 60-180 minutes, with the ratio of the second melting rate to the crystallizer diameter being 0.55-0.95. At the beginning of the stable remelting phase, the cooling effect of the bottom water tank on the resulting remelted ingot weakens, and the electroslag ingot relies primarily on the crystallizer for cooling. Continuing to use the first melting rate at the end of the rapid remelting phase would result in a deeper molten metal pool and a poorer solidification structure. Therefore, upon entering the stable remelting phase, the remelting rate is reduced to maintain the same shallow and flat shape as in the rapid remelting phase, thus ensuring the consistency of the longitudinal solidification structure of the electroslag ingot.
[0010] Furthermore, the current during the rapid remelting stage is controlled between 6000A and 15000A, with current fluctuations between ±300A and ±1500A. Generally speaking, the larger the current value, the greater the current fluctuation within the fluctuation range.
[0011] Furthermore, in the initial stage of the stable remelting phase, the control current is gradually reduced to 4000~10000A within 60min~180min, with current fluctuation values between ±200A~±1000A.
[0012] During the rapid remelting and stable remelting stages, the current used for remelting is highly sensitive to changes. By controlling the fluctuations in the current, the insertion depth of the consumable electrode can be controlled, ensuring that the insertion depth remains constant. If slag resistance is used to control the insertion depth of the consumable electrode, changes in the slag pool composition during remelting may lead to changes in the basic properties of the slag pool, which in turn will cause changes in the insertion depth.
[0013] Furthermore, the slag-making electrode used in the arc-initiation and slag-making stage is made of pure iron with a melting point ≥1530℃, while the melting point of the slag material used for slag-making is ≤1300℃; the slag-making temperature is ≤1500℃. The use of pure iron electrodes for slag-making, with a melting point higher than that of the slag material and the high-alloy materials being smelted, effectively prevents the slag-making electrode from melting during the arc-initiation and slag-making stage, avoiding the problem of carbon buildup at the bottom of the electroslag ingot caused by traditional graphite electrode slag-making. It also solves the problem of poor quality at the bottom of the electroslag ingot obtained when using consumable electrodes for solid slag arc initiation.
[0014] Furthermore, the melting point of the high-alloy materials smelted is ≤1450℃.
[0015] Furthermore, the slag-forming electrode has a cylindrical structure with a first argon gas channel running through it axially. This channel is used to introduce argon gas during the arc-starting slag-forming stage, with a flow rate of 10-60 L / min. The first argon gas channel in the slag-forming electrode helps remove gases generated during the slag-forming process by introducing argon gas into the slag pool during the arc-starting slag-forming stage. At this time, a small amount of moisture inside the crystallizer will also evaporate into water vapor upon heating; introducing argon gas further helps to remove this water vapor, thus further solving the problem of hydrogen accumulation at the bottom of the electroslag ingot. Furthermore, the first argon gas channel includes an inlet section, a transition section, and an outlet, arranged sequentially from top to bottom. The inlet section and outlet are located at the top and bottom of the slag-forming electrode, respectively. Argon gas enters from the inlet section, is redistributed through the transition section, and flows into the slag pool through the outlet to promote the removal of gases from the slag pool.
[0016] Furthermore, the height of the inlet section accounts for 1 / 2 to 3 / 4 of the height of the slag electrode, the diameter of the transition section is larger than that of the inlet section, and multiple outlet holes are evenly spaced radially along the transition section. Argon gas enters through the inlet section, is redistributed within the transition section, and is then sent into the slag pool through the outlet holes, which helps to expand the agitation area and agitation effect of the slag pool.
[0017] Furthermore, the diameter of a single outlet is 3~10mm; and the number of outlets is 6~12.
[0018] Compared with the prior art, the technical solution provided by this invention has the following advantages: (1) This invention optimizes the remelting stage by dividing it into a rapid remelting stage and a stable remelting stage, and optimizes the first melting rate of the rapid remelting stage to further improve the melting rate of the rapid remelting stage, that is, by increasing the value of the first melting rate, so as to make full use of the excess cooling performance of the bottom water tank and the crystallizer. The setting of this first melting rate still maintains the metal pool of the rapid remelting stage as shallow and flat, which further improves the efficiency of electroslag remelting and reduces power consumption while ensuring good solidification quality of the remelted ingot. Furthermore, in the early stage of the stable remelting stage, the melting rate is reduced from the first melting rate to the second melting rate at the same rate within 60 min to 180 min, and the ratio of the second melting rate to the diameter of the crystallizer is 0.55 to 0.95; so that the shape of the metal pool in this stage remains the same as that in the rapid remelting stage, thereby ensuring the consistency of the solidification structure of the electroslag ingot along the longitudinal direction.
[0019] (2) The present invention further optimizes the oscillation mode of the remelting stage. Specifically, the current during the rapid remelting stage is controlled between 6000A and 15000A, with current fluctuations between ±300A and ±1500A. In the initial stage of the stable remelting stage, the current gradually decreases to 4000A to 10000A within 60 to 180 minutes, with current fluctuations between ±200A and ±1000A. During both the rapid and stable remelting stages, the insertion depth of the consumable electrode is controlled by controlling the current fluctuations. Because the current changes during the remelting process are sensitive, this control method ensures that the insertion depth remains constant during the remelting process.
[0020] (3) The present invention further optimizes the design of the slag-forming stage of electroslag remelting. Specifically, the slag-forming electrode uses a pure iron electrode, which avoids the problem of carbon accumulation at the bottom of the electroslag ingot caused by the traditional use of graphite electrodes for slag-forming. At the same time, it solves the problem of poor quality at the bottom of the electroslag ingot due to the solidification of the consumable electrode and arc initiation. In addition, a first argon gas channel is set inside the slag-forming electrode to remove gas from the slag and solve the problem of easy hydrogen accumulation at the bottom of the electroslag ingot. Attached Figure Description
[0021] Figure 1 This is a simulation diagram of the molten pool shape during the rapid remelting stage in the electroslag remelting process of the present invention.
[0022] Figure 2 This is a schematic diagram of the arc initiation and slag formation stage during the electroslag remelting process according to an embodiment of the present invention.
[0023] Figure 3 This is a schematic diagram of the feeding stage in the electroslag remelting process according to an embodiment of the present invention.
[0024] Explanation of icon numbers: 1. Slag-reducing electrode; 101. First argon gas channel; 111. Inlet section; 112. Transition section; 113. Outlet port; 2. Crystallizer; 3. Bottom water tank; 4. Slag pit; 5. Compensation for self-consumable electrodes; 501. First stage of feeding electrode; 502. Second stage of feeding electrode; 503. Third-stage compensation electrode; 504, Second Argon Gas Channel. Detailed Implementation
[0025] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.
[0026] In the following examples and comparative examples, unless otherwise specified, the ratio of melting rate to crystallizer diameter is expressed in kg / h for melting rate and in mm for crystallizer diameter.
[0027] Example 1 This embodiment provides a method for electroslag remelting of high alloy materials, referencing... Figure 2 As shown, the slag-refining electrode 1 used is made of pure iron with a melting point ≥1530℃. The slag-refining electrode 1 has a cylindrical structure, in which a first argon gas channel 101 is provided through it along its axial direction. The first argon gas channel 101 includes an inlet section 111, a transition section 112 and an outlet hole 113 arranged sequentially from top to bottom. The inlet section 111 and the outlet hole 113 are respectively opened at the top and bottom of the slag-refining electrode 1. Argon gas enters from the inlet section 111, is redistributed through the transition section 112, and flows into the slag pool 4 from the outlet hole 113 to promote the discharge of gas in the slag pool 4.
[0028] Regarding the specific structural design of the slag-reducing electrode 1, the diameter of the first argon gas channel 101 can be set to 20mm~40mm, and in this embodiment, the diameter of the first argon gas channel 101 is set to 30mm; the height of the inlet section 111 can be set to 1 / 2~3 / 4 of the overall height of the slag-reducing electrode 1, and in this embodiment, the height of the inlet section 111 accounts for 2 / 3; the diameter of the transition section 112 is larger than the diameter of the inlet section 111, and the outlet holes 113 are evenly arranged radially along the transition section 112, with a number of 6~12, and the diameter of a single outlet hole 113 is 3~10mm. In this embodiment, the number of outlet holes 113 is designed to be 8, and the diameter of a single outlet hole 113 is designed to be 5mm.
[0029] The slag material used for slag melting has a melting point of ≤1300℃ and a slag melting temperature of ≤1500℃; the consumable electrode used has an Al content of 0.180% and a hydrogen content of 0.00018%.
[0030] In this embodiment, the diameter of the crystallizer 2 is 500 mm, and the height of the remelted ingot used for smelting is 2100 mm.
[0031] The electroslag remelting process includes the following steps: S1. Use slag-initiating electrode 1 to perform arc slag initiation; the slag melting time is 45 min; 10 min before the end of slag initiation, add 150 g of aluminum particles and 300 g of SiCa alloy deoxidizer in sequence; wherein, argon gas with a flow rate of 35 g / min is introduced into the first argon gas channel 101 in slag-initiating electrode 1.
[0032] S2. Remove the slag electrode 1 and quickly feed it into the consumable electrode to enter the rapid remelting stage. The consumable electrode is cast from the smelted high-alloy molten metal. A high-power, high-speed remelting process is adopted, with the current controlled between 6000 and 15000A, and the current fluctuation value between ±300A and ±1500A. As the current increases, the current fluctuation value increases. Gradually increase the melting rate to the first melting rate. The ratio of the first melting rate to the diameter of the crystallizer 2 is 1.3. The unit of the first melting rate is kg / h, and the unit of the diameter of the crystallizer 2 is mm.
[0033] S3. When the height of the remelted ingot inside the crystallizer 2 is equal to the diameter of the crystallizer 2, the stable remelting stage begins. The current is gradually reduced to 4000A~10000A within 120 minutes, with a current fluctuation value of ±200A~±1000A. At the same time, the melting rate is reduced from the first melting rate to the second melting rate, and the ratio of the second melting rate to the diameter of the crystallizer 2 is 0.75.
[0034] S4, Entering the shrinkage phase.
[0035] S5, Demolding of electroslag ingots.
[0036] In this embodiment, a remelted ingot was prepared. After removing the slag, the Al content along the longitudinal outer edge was measured. Sampling points were specifically taken at distances of 1 / 5H, 2 / 5H, 3 / 5H, 4 / 5H, and 5 / 5H from the bottom surface of the electroslag ingot, where H represents the total height of the electroslag ingot after slag removal. These points were named a1, a2, a3, a4, and a5, respectively. The hydrogen content was also measured at a cross-section 100mm from the bottom surface. Sampling points were taken along a certain radius at distances of 0mm, 1 / 4R, 2 / 4R, 3 / 4R, and R from the center of the cross-section, respectively, and named b1, b2, b3, b4, and b5. Detailed test results are shown in Table 1. The rapid remelting stage took 83 minutes and consumed 803 kW·h of electrical energy.
[0037] Comparative Example 1 This comparative example provides an electroslag remelting method for high alloy materials, which differs from Example 1 in that: in the rapid remelting stage, the ratio of the first melting rate to the crystallizer diameter is 1.2, where the unit of the first melting rate is kg / h and the unit of the crystallizer diameter is mm; the rest of the operations are basically the same.
[0038] The remelted ingot prepared in this comparative example was sampled and tested. The Al content along the longitudinal outer edge was measured. The sampling points were selected and named in the same way as in Example 1. The test results are detailed in Table 1. Meanwhile, the rapid remelting stage took 92 minutes and consumed 880 kW·h of electrical energy.
[0039] As shown in Table 1, compared with Example 1, Comparative Example 1 has a smaller difference in the distribution of aluminum content along the longitudinal direction of the electroslag ingot, consumes slightly more electrical energy than Example 1, and has a slightly lower remelting efficiency than Example 1.
[0040] Comparative Example 2 This comparative example provides an electroslag remelting method for high alloy materials, which differs from Example 1 in that: in the rapid remelting stage, the ratio of the first melting rate to the crystallizer diameter is 1.35, where the unit of the first melting rate is kg / h and the unit of the crystallizer diameter is mm; the rest of the operations are basically the same.
[0041] The remelted ingots prepared in this comparative example were sampled and tested. The Al content along the longitudinal outer edge was measured. The sampling points were the same as in Example 1. The test results are detailed in Table 1. Meanwhile, the rapid remelting stage took 80 minutes and consumed 790 kW·h of electrical energy.
[0042] As shown in Table 1, although Comparative Example 2 consumes slightly less electrical energy and has a slightly higher remelting efficiency than Example 1, the difference in aluminum content distribution along the longitudinal direction of the resulting electroslag ingot is greater.
[0043] Comparative Example 3 This comparative example provides an electroslag remelting method for high alloy materials, which differs from Example 1 in that it uses a graphite electrode for arc initiation and slag formation; the remaining operations are basically the same.
[0044] The remelted ingots prepared in this comparative example were sampled and tested. The hydrogen content of the cross-section 100 mm from the bottom end was tested. The selection and naming of the sampling points were the same as in Example 1. The test results are detailed in Table 1.
[0045] As shown in Table 1, compared with Example 1, the hydrogen content at the bottom of the electroslag ingot obtained in Comparative Example 3 is significantly increased compared with the hydrogen content of the electroslag ingot and consumable electrode prepared in Example 1.
[0046] Example 2 This embodiment provides an electroslag remelting method for high-alloy materials, which differs from Embodiment 1 in that the electroslag remelting process parameters are slightly different, as detailed below: In this embodiment, the diameter of the crystallizer 2 is 600 mm, and the height of the remelted ingot used for smelting is 2400 mm.
[0047] The electroslag remelting process includes the following steps: S1. Use slag-initiating electrode 1 to perform arc slag initiation; the slag melting time is 30 min; 10 min before the end of slag initiation, add 100 g of aluminum particles and 200 g of SiCa alloy deoxidizer in sequence; during the slag initiation process, argon gas with a flow rate of 10 / min is introduced into the first argon gas channel 101 of slag-initiating electrode 1.
[0048] S2. Remove the slag electrode 1 and quickly feed it into the consumable electrode to enter the rapid remelting stage. The consumable electrode is cast from the smelted high-alloy molten metal. A high-power, high-speed remelting process is adopted, with the current controlled between 6000A and 15000A, and the current fluctuation value between ±300A and ±1500A. As the current increases, the current fluctuation value increases. Gradually increase the melting rate to the first melting rate. The ratio of the first melting rate to the crystallizer diameter is 1.3. The unit of the first melting rate is kg / h, and the unit of the crystallizer diameter is mm.
[0049] S3. When the height of the remelted ingot inside the crystallizer 2 is equal to the diameter of the crystallizer 2, the stable remelting stage begins. The current is gradually reduced to 4000~10000A within 60 minutes, with a current fluctuation value of ±200A~±1000A. At the same time, the melting rate is reduced from the first melting rate to the second melting rate, and the ratio of the second melting rate to the diameter of the crystallizer 2 is 0.95.
[0050] S4, Entering the shrinkage phase.
[0051] S5, Demolding of electroslag ingots.
[0052] The remelted ingot prepared in this embodiment has similar properties to the electroslag ingot obtained by smelting in Example 1; wherein, the rapid remelting stage takes 132 minutes and consumes 1450 kW.h of electrical energy.
[0053] Example 3 This embodiment provides an electroslag remelting method for high-alloy materials, which differs from Embodiment 1 in that the electroslag remelting process parameters are slightly different, as detailed below: In this embodiment, the diameter of the crystallizer 2 is 400 mm, and the height of the remelted ingot used for smelting is 1800 mm.
[0054] The electroslag remelting process includes the following steps: S1. Use slag-initiating electrode 1 to perform arc slag initiation; the slag melting time is 60 min; 10 min before the end of slag initiation, add 200 g of aluminum particles and 400 g of SiCa alloy deoxidizer in sequence; during the slag initiation process, argon gas with a flow rate of 60 g / min is introduced into the first argon gas channel 101 of slag-initiating electrode 1.
[0055] S2. Remove the slag electrode 1 and quickly feed it into the consumable electrode to enter the rapid remelting stage. The consumable electrode is cast from the smelted high-alloy molten metal. A high-power, high-speed remelting process is adopted, with the current controlled between 6000A and 15000A, and the current fluctuation value between ±300A and ±1500A. As the current increases, the current fluctuation value increases. Gradually increase the melting rate to the first melting rate. The ratio of the first melting rate to the crystallizer diameter is 1.3. The unit of the first melting rate is kg / h, and the unit of the crystallizer diameter is mm.
[0056] S3. When the height of the remelted ingot inside the crystallizer 2 is equal to the diameter of the crystallizer 2, the stable remelting stage begins. The current is gradually reduced to 4000A~10000A within 180 minutes, with a current fluctuation value of ±200A~±1000A. At the same time, the melting rate is reduced from the first melting rate to the second melting rate, and the ratio of the second melting rate to the diameter of the crystallizer 2 is 0.55.
[0057] S4, Entering the shrinkage phase.
[0058] S5, Demolding of electroslag ingots.
[0059] The remelted ingot prepared in this embodiment has similar properties to the electroslag ingot obtained by smelting in Example 1; wherein, the rapid remelting stage takes 53 minutes and consumes 430 kW.h of electrical energy.
[0060] Example 4 It should be noted that in the feeding stage of S4 in the above embodiments 1-3, the self-consumable electrode itself can be used as the feeding self-consumable electrode. The feeding of the core at the top of the electroslag ingot can be achieved by gradually reducing the melting rate. Alternatively, a feeding self-consumable electrode with a smaller diameter can be provided on the top of the self-consumable electrode and fixedly arranged coaxially with it. The feeding self-consumable electrode 5 and feeding process of this embodiment can also be used.
[0061] refer to Figure 3 As shown, the self-consumable electrode 5 used in this embodiment S4 includes a first self-consumable electrode 501, a second self-consumable electrode 502, and a third self-consumable electrode 503, which are coaxially arranged from bottom to top and have decreasing diameters. The diameter of the first self-consumable electrode 501 is 0.9 times that of the self-consumable electrode, and 0.8 times that of the crystallizer 2. The mass of the first self-consumable electrode 501 accounts for 10% of the total mass of the remelted ingot. The diameter of the second self-consumable electrode 502 is 0.6 times that of the crystallizer 2, and 6% of the total mass of the remelted ingot. The diameter of the third self-consumable electrode 503 is 0.4 times that of the crystallizer 2, and 4% of the total mass of the remelted ingot. The third self-consumable electrode 503 has a second argon gas channel 504 that extends longitudinally through its interior.
[0062] The specific process of this feeding stage is as follows: When the mass of the remelted ingot obtained inside the crystallizer reaches 80% of the total mass of the remelted ingot, the electroslag remelting enters the feeding stage; the consumable electrode is replaced with a feeding consumable electrode 5, and the melting rate of the first feeding electrode 501 used in the remelting stage is 0.4 times the diameter of the crystallizer 2; the melting rate of the second feeding electrode 502 used in the remelting stage is 0.3 times the diameter of the crystallizer 2; when the third feeding electrode 503 is remelting, the melting rate is 0.2 times the diameter of the crystallizer 2, and the flow rate of argon gas introduced into the second argon gas channel 504 is 10 L / min, which is used to promote the droplets in the third feeding electrode 103 to pass through the slag pool and drip into the molten metal pool.
[0063] By designing the above-mentioned self-consumable electrode 5 for feeding and the corresponding melting rate for each segment, the diameter and depth of the feeding pit at the top of the electroslag ingot can be effectively reduced, thereby improving the metal yield of electroslag remelting.
Claims
1. A method for electroslag remelting of high-alloy materials, characterized in that, This includes a remelting stage, which comprises a rapid remelting stage and a stable remelting stage; wherein: When the height of the remelted ingot inside the crystallizer (2) is less than the diameter of the crystallizer, it is a rapid remelting stage. In this stage, the melting rate first gradually increases to the first melting rate, and then the first melting rate is maintained to continue remelting. The ratio of the first melting rate to the diameter of the crystallizer is 1.
3. The unit of the first melting rate is kg / h, and the unit of the diameter of the crystallizer is mm. When the height of the remelted ingot inside the crystallizer (2) is equal to the diameter of the crystallizer, it enters the stable remelting stage from the rapid remelting stage. In the early stage of the stable remelting stage, the melting rate gradually decreases from the first melting rate to the second melting rate, and then maintains the second melting rate until the end of the stable remelting stage.
2. The electroslag remelting method for high-alloy materials according to claim 1, characterized in that, In the initial stage of the stable remelting phase, the melting rate is reduced from the first melting rate to the second melting rate at a constant rate within 60 min to 180 min, and the ratio of the second melting rate to the crystallizer diameter is 0.55 to 0.
95.
3. The electroslag remelting method for high-alloy materials according to claim 2, characterized in that, The current during the rapid remelting stage is controlled between 6000A and 15000A, with current fluctuations between ±300A and ±1500A.
4. The electroslag remelting method for high-alloy materials according to claim 3, characterized in that, In the initial stage of stable remelting, the control current is gradually reduced to 4000A~10000A within 60min~180min, and the current fluctuation value is between ±200A~±1000A.
5. The electroslag remelting method for high-alloy materials according to any one of claims 1-4, characterized in that, The electroslag remelting includes an arc initiation and slag-forming stage before the remelting stage. The slag-forming electrode (1) used in the arc initiation and slag-forming stage is made of pure iron with a melting point ≥1530℃. The melting point of the slag material used for slag-forming is ≤1300℃ and the slag-forming temperature is ≤1500℃.
6. The electroslag remelting method for high-alloy materials according to claim 5, characterized in that, The melting point of the high alloy materials smelted is ≤1450℃.
7. The electroslag remelting method for high-alloy materials according to claim 5, characterized in that, The slag-forming electrode (1) is a cylindrical structure, in which a first argon gas channel (101) is provided to pass through along its axial direction, for introducing argon gas during the arc-starting slag-forming stage, and the flow rate of the introduced argon gas is 10~60L / min.
8. The electroslag remelting method for high-alloy materials according to claim 7, characterized in that, The first argon channel (101) includes an inlet section (111), a transition section (112), and an outlet (113) arranged sequentially from top to bottom. The inlet section (111) and the outlet (113) are respectively located at the top and bottom of the slag electrode (1). Argon enters from the inlet section (111), is redistributed through the transition section (112), and flows into the slag pool (4) through the outlet (113) to promote the discharge of gas from the slag pool (4).
9. The electroslag remelting method for high-alloy materials according to claim 8, characterized in that, The height of the air inlet section (111) is 1 / 2 to 3 / 4 of the height of the slag electrode (1). The diameter of the transition section (112) is larger than the diameter of the air inlet section (111). Multiple air outlet holes (113) are evenly spaced along the radial direction of the transition section (112).
10. The electroslag remelting method for high-alloy materials according to claim 9, characterized in that, The diameter of a single vent (113) is 3~10mm; the number of vents is 6~12.