Feeding consumable electrode for electroslag remelting and feeding method thereof

Abstract

The invention discloses a feeding consumable electrode for electroslag remelting and a feeding method thereof, and belongs to the technical field of electroslag remelting. The feeding consumable electrode comprises a first-section feeding electrode, a second-section feeding electrode and a third-section feeding electrode which are coaxially arranged from bottom to top and have gradually decreased diameters, and a first argon gas channel penetrating in the longitudinal direction is formed in the third-section feeding electrode and used for promoting liquid drops in the third-section feeding electrode to penetrate through the slag pool to drip into the metal molten pool. In the feeding stage in the electroslag remelting process, a consumable electrode is replaced with a feeding consumable electrode, when a third-section feeding electrode is remelted, argon is introduced into a first argon channel, and the flow speed of the argon is 5-10 L / min. According to the scheme, the feeding electrode used in the feeding stage is optimally designed, and the caliber and the depth of the electroslag ingot feeding pit can be reduced.

Description

Technical Field

[0001] This invention relates to the field of electroslag remelting technology, and more specifically, to a feeding consumable electrode for electroslag remelting and a feeding method thereof. 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 feeding stage in the electroslag remelting process typically suffers from the following problems: if the feeding process is not properly implemented, pits may appear at the top after feeding, eventually requiring the pits to be removed, reducing metal yield and increasing the production cost of the electroslag ingot. Existing technologies generally address this by reducing the melting rate or by incorporating a smaller-diameter feeding section at the top of the consumable electrode. While these two designs can reduce the size of the feeding pits in the resulting electroslag ingot to some extent, there is still room for further optimization. Summary of the Invention

[0004] 1. Technical problems to be solved This invention provides a feeding consumable electrode for electroslag remelting and a feeding method thereof. By optimizing the design of the feeding electrode used in the feeding stage, the diameter and depth of the feeding pit in the electroslag ingot can be reduced, thereby improving the metal yield of electroslag remelting.

[0005] 2. Technical solutions adopted To achieve the above objectives, the technical solution provided by the present invention is as follows: The first aspect of the present invention provides a feeding consumable electrode for electroslag remelting, the feeding consumable electrode comprising a first feeding electrode, a second feeding electrode and a third feeding electrode arranged coaxially from bottom to top with decreasing diameter; wherein, the interior of the third feeding electrode is provided with a first argon gas channel running longitudinally through it, for promoting the droplets in the third feeding electrode to pass through the slag pool and drip into the molten metal pool.

[0006] In existing electroslag remelting processes, the feeding stage typically involves gradually reducing the melting rate to accommodate the decreasing diameter and depth of the molten pool. Additionally, some studies have explored methods such as placing a smaller-diameter feeding electrode at the top of the consumable electrode, or using a consumable electrode with a diameter that gradually decreases from bottom to top, with the corresponding frustum-shaped section at the top of the consumable electrode essentially serving as the feeding electrode. Both of these methods inevitably lead to the following problems: in the later stages of feeding, due to the lower melting rate and slag temperature, further reducing the melting rate of the feeding consumable electrode results in a slower rate at which the molten droplets formed by the electrode pass through the slag pool and drip onto the top of the remelted ingot. This limits further reductions in the diameter of the feeding section and the melting rate, severely restricting feeding efficiency. Furthermore, it also hinders the control of the size of the top replenishment pit. By adding a first argon gas channel inside the uppermost third feeding electrode, the droplets in the third feeding electrode can be facilitated to drip through the slag pool and fall into the molten metal pool, thus overcoming the limitations on further reducing the diameter of the feeding section and the melting rate, and achieving a good synergy between feeding quality and feeding efficiency.

[0007] Furthermore, the ratio of the diameter of the third feeding electrode to the diameter of the crystallizer is 0.2~0.4, and the diameter of the argon channel is 5~10mm. Compared with the electrode diameter corresponding to the existing feeding section, the ratio of the diameter of the uppermost feeding section to the diameter of the crystallizer is further reduced, thereby better adapting to the changing pattern of the shrinkage of the molten pool diameter at the feeding end. Under the action of gas thrust in the argon channel, the feeding electrode section with a smaller diameter at its top can achieve micro-volume and precise metal molten metal supply.

[0008] Furthermore, the diameter of the first feeding electrode is 80% to 90% of the diameter of the consumable electrode used in the remelting stage, and the ratio of its diameter to the crystallizer diameter is 0.6 to 0.8. The ratio of the diameter of the second feeding electrode to the crystallizer diameter is 0.4 to 0.6, to adapt to the shrinkage process of the molten pool diameter gradually decreasing. Generally speaking, the ratio of the diameter of the corresponding feeding electrode segment to the crystallizer diameter takes the upper limit of this ratio range for larger crystallizers and the lower limit of this ratio range for smaller crystallizers.

[0009] Furthermore, the first feeding electrode accounts for 6% to 10% of the total mass of the remelted ingot, the second feeding electrode accounts for 3% to 6% of the total mass, and the third feeding electrode accounts for 2% to 4% of the total mass. As the melting rate decreases, the size of the molten metal pool decreases accordingly, and the amount of feeding required for its solidification process also decreases. Based on the temperature field variation law of the molten pool obtained from numerical simulation, this design accurately designs the different mass proportions of the feeding electrode segments and their corresponding melting rates in the subsequent feeding process.

[0010] The second aspect of the present invention provides a feeding method for electroslag remelting, wherein feeding self-consumable electrode of any of the above-mentioned methods is used for feeding during the feeding stage. When the mass of the remelted ingot obtained inside the crystallizer reaches 80% to 88% of the total weight of the remelted ingot, the electroslag remelting enters the feeding stage. Specifically, the self-consumable electrode is replaced with a feeding self-consumable electrode. When the feeding electrode of the third stage of remelting is used, argon gas is introduced into the argon gas channel at a flow rate of 5-10 L / min.

[0011] Furthermore, the ratio of the melting rate to the crystallizer diameter used in remelting the third feeding electrode is 0.05 to 0.2.

[0012] Furthermore, the ratio of the melting rate to the crystallizer diameter used in the first stage of remelting the feeding electrode is 0.4 to 0.7; the ratio of the melting rate to the crystallizer diameter used in the second stage of remelting the feeding electrode is 0.2 to 0.4.

[0013] A third aspect of the present invention provides an electroslag remelting apparatus, the apparatus comprising a crystallizer, a bottom water tank, a consumable electrode, and a feeding consumable electrode as described above, wherein the feeding consumable electrode is used to replace the consumable electrode for remelting during the feeding stage.

[0014] Furthermore, the device also includes a slag-forming electrode, which has a second argon gas channel extending along its axial direction for introducing argon gas during the arc-starting slag-forming stage to promote the discharge of gas inside the slag pool during the slag-forming stage; wherein, the slag-forming electrode is made of pure iron electrode, and its melting point is greater than the slag-forming temperature and the melting point of the consumable electrode.

[0015] Compared with the prior art, the technical solution provided by this invention has the following advantages: (1) The present invention optimizes the design of the self-consuming electrode used in the feeding stage of electroslag remelting. Specifically, the third feeding electrode is provided with a first argon gas channel. At the end of the feeding stage, argon gas is introduced into the first argon gas channel. Under the action of argon gas, the molten droplets at the bottom of the third feeding electrode can be dropped quickly, so that a smaller melting rate can be used, thereby improving the feeding quality and feeding efficiency.

[0016] (2) The present invention further optimizes the design of the feeding self-consumable electrode. Specifically, in the feeding stage, a three-segment feeding self-consumable electrode with decreasing diameter from bottom to top is adopted. The diameter of the feeding self-consumable electrode is gradually reduced, so that the formed droplet region is more in line with the shrinkage law of the metal pool diameter. The core of the top of the electroslag ingot is accurately fed, which helps to reduce defects such as shrinkage cavities and pits at the top, thereby reducing the amount of material removed from the head of the electroslag ingot and improving the metal yield. Furthermore, based on the temperature field change law of the molten pool obtained by numerical simulation, the mass ratio of each feeding electrode segment and its corresponding melting rate in the subsequent feeding process are accurately designed. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the feeding stage in the electroslag remelting process according to an embodiment of the present invention.

[0018] 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.

[0019] Explanation of reference numerals in the attached figures: 1. Compensation for consumable electrodes; 101. First stage of feeding electrode; 102. Second stage feeding electrode; 103. Third-stage compensation electrode; 104. First argon gas passage; 2. Crystallizer; 3. Bottom water tank; 4. Slag pit; 5. Slag-removing electrode; 501. Second argon gas channel. Detailed Implementation

[0020] 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.

[0021] 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 mm for crystallizer diameter.

[0022] Example 1 This embodiment provides a method for electroslag remelting, referencing... Figure 1 As shown, the feeding self-consumable electrode 1 includes a first feeding electrode 101, a second feeding electrode 102, and a third feeding electrode 103 arranged coaxially from bottom to top with decreasing diameters; wherein the diameter of the first feeding electrode 101 is 0.85 times the diameter of the self-consumable electrode used in the remelting stage, the diameter of the first feeding electrode 101 is 0.7 times the diameter of the crystallizer 2, and the mass of the first feeding electrode 101 accounts for 8% of the total mass of the remelted ingot; the diameter of the second feeding electrode 102 is 0.5 times the diameter of the crystallizer 2, and the mass of the second feeding electrode 102 accounts for 5% of the total mass of the remelted ingot; the diameter of the third feeding electrode 103 is 0.3 times the diameter of the crystallizer 2, and the mass of the third feeding electrode 103 accounts for 2% of the total mass of the remelted ingot.

[0023] The third feeding electrode 103 has a first argon gas channel 104 running longitudinally inside. The diameter of the first argon gas channel 104 can be 5~10mm. In this embodiment 1, the diameter of the first argon gas channel 104 is set to 8mm, 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.

[0024] The diameter of the crystallizer 2 used in this embodiment is 500 mm.

[0025] The electroslag remelting process includes the following steps: S1, Arc initiation and slag formation stage; S2, remelting stage; S3, Feeding Stage: When the mass of the remelted ingot obtained inside the crystallizer 2 reaches 85% of the total mass of the remelted ingot, the electroslag remelting enters the feeding stage; the consumable electrode is replaced with the feeding consumable electrode 1, and the ratio of the melting rate used for the first feeding electrode 101 to the diameter of the crystallizer 2 is 0.55; the ratio of the melting rate used for the second feeding electrode 102 to the diameter of the crystallizer 2 is 0.3; when remelting the third feeding electrode 103, the ratio of the melting rate used to the diameter of the crystallizer 2 is 0.1, and the flow rate of argon gas introduced into the first argon gas channel 104 is 8L / min; S4. Demolding of electroslag ingots.

[0026] The remelted ingot prepared in this embodiment, after the slag skin is removed, has an upward-facing protrusion at its top, with a diameter of 200 mm at the bottom and a height of approximately 3 mm. Compared to the conventional pitted top, this significantly reduces the amount of material removed from the resulting electroslag ingot, thereby improving the metal yield during the remelting process. Comparative Example 1 This comparative example provides a method for electroslag remelting, which differs from Example 1 in that: the self-consumable feeding electrode 1 used in this method is composed of a first feeding electrode 101 of the same size as in Example 1, the mass of the first feeding electrode 101 accounts for 15% of the total mass of the remelted ingot, and it does not include the second feeding electrode 102 and the third feeding electrode 103. Accordingly, the relevant melting rate control operation in the electroslag remelting process is omitted; the rest of the operation is basically the same.

[0027] The remelted ingot prepared in this comparative example, after the slag skin is removed, has a pit at its top with a diameter of 380 mm and a depth of 30 mm.

[0028] Comparative Example 2 This comparative example provides a method for electroslag remelting, which differs from Example 1 in that: the feeding self-consumable electrode 1 used in this method consists of a first feeding electrode 101 and a second feeding electrode 102 of the same size as in Example 1. The mass of the first feeding electrode 101 accounts for 10% of the total mass of the remelted ingot, and the mass of the second feeding electrode 102 accounts for 5% of the total mass of the remelted ingot. It does not include the third feeding electrode 103. Accordingly, the relevant melting rate control operation in the electroslag remelting process is omitted, and the remaining operations are basically the same.

[0029] The remelted ingot prepared in this comparative example, after the slag skin is removed, has a pit at its top with a diameter of 300 mm and a depth of 25 mm.

[0030] Comparative Example 3 This comparative example provides a method for electroslag remelting, which differs from Example 1 in that: the feeding self-consumable electrode 1 used in this method consists of a first feeding electrode 101 and a second feeding electrode 102 of the same size as in Example 1. The mass of the first feeding electrode 101 accounts for 10% of the total mass of the remelted ingot, and the mass of the second feeding electrode 102 accounts for 5% of the total mass of the remelted ingot. Furthermore, an argon gas channel is provided inside the second feeding electrode 102. Accordingly, the operation of introducing argon gas in the electroslag remelting process is omitted, and the remaining operations are basically the same.

[0031] The remelted ingot prepared in this comparative example, after the slag skin was removed, formed a pit at the top of the ingot. The pit had a diameter of 300 mm and a depth of 22 mm.

[0032] Comparative Example 4 This embodiment provides a method for electroslag remelting, which differs from Embodiment 1 in that: no argon gas channel is provided inside the third-stage feeding electrode 103, and correspondingly, the relevant argon gas introduction operation in the electroslag remelting process is omitted, while the remaining operations are basically the same.

[0033] The remelted ingot prepared in this comparative example, after slag removal, had a pit formed at its top. The pit had a diameter of 280 mm and a depth of 20 mm. The net weight of the final electroslag ingot was reduced compared to Example 1. The reason is as follows: based on the size of the formed pit, the required remelted ingot height to be removed was 20 mm. Compared to the protrusion formed in Example 1, the amount of material removed in Example 1 was significantly reduced.

[0034] Example 2 This embodiment provides a method for electroslag remelting, which differs from Embodiment 1 in that the size of the feeding consumable electrode 1 used is different and the process parameters for electroslag remelting are slightly different, as detailed below: The feeding self-consumable electrode 1 used includes a first feeding electrode 101, a second feeding electrode 102, and a third feeding electrode 103 arranged coaxially from bottom to top with decreasing diameters; wherein the diameter of the first feeding electrode 101 is 0.8 times the diameter of the self-consumable electrode used in the remelting stage, the diameter of the first feeding electrode 101 is 0.6 times the diameter of the crystallizer 2, and the mass of the first feeding electrode 101 accounts for 6% of the total mass of the remelted ingot; the diameter of the second feeding electrode 102 is 0.4 times the diameter of the crystallizer 2, and the mass of the second feeding electrode 102 accounts for 3% of the total mass of the remelted ingot; the diameter of the third feeding electrode 103 is 0.2 times the diameter of the crystallizer 2, and the mass of the third feeding electrode 103 accounts for 3% of the total mass of the remelted ingot.

[0035] The diameter of the crystallizer 2 used in this embodiment is 400 mm.

[0036] The electroslag remelting process includes the following steps: S1, Arc initiation and slag formation stage; S2, remelting stage; S3. When the mass of the remelted ingot obtained inside the crystallizer reaches 88% of the total mass of the remelted ingot, the electroslag remelting enters the feeding stage; the consumable electrode is replaced with the feeding consumable electrode 1, and the ratio of the melting rate of the first feeding electrode 101 to the diameter of the crystallizer 2 is 0.4; the ratio of the melting rate of the second feeding electrode 102 to the diameter of the crystallizer 2 is 0.2; when the third feeding electrode 103 is remelting, the ratio of the melting rate to the diameter of the crystallizer 2 is 0.05, and the flow rate of argon gas introduced into the first argon gas channel 104 is 5L / min; S4. Demolding of electroslag ingots.

[0037] The remelted ingot prepared in this embodiment has an upward protrusion at its top after the slag is removed. The diameter of the bottom of the protrusion is 160 mm and its height is about 3 mm.

[0038] Example 3 This embodiment provides a method for electroslag remelting, which differs from Embodiment 1 in that the size of the feeding consumable electrode 1 used is different and the process parameters for electroslag remelting are slightly different, as detailed below: The feeding self-consumable electrode 1 used includes a first feeding electrode 101, a second feeding electrode 102, and a third feeding electrode 103 arranged coaxially from bottom to top with decreasing diameters; wherein the diameter of the first feeding electrode 101 is 0.9 times the diameter of the self-consumable electrode used in the remelting stage, the diameter of the first feeding electrode 101 is 0.8 times the diameter of the crystallizer 2, and the mass of the first feeding electrode 101 accounts for 10% of the total mass of the remelted ingot; the diameter of the second feeding electrode 102 is 0.6 times the diameter of the crystallizer 2, and the mass of the second feeding electrode 102 accounts for 6% of the total mass of the remelted ingot; the diameter of the third feeding electrode 103 is 0.4 times the diameter of the crystallizer 2, and the mass of the third feeding electrode 103 accounts for 4% of the total mass of the remelted ingot.

[0039] The crystallizer 2 used in this embodiment has a diameter of 600 mm.

[0040] The electroslag remelting process includes the following steps: S1, Arc initiation and slag formation stage; S2, remelting stage; S3, Feeding Stage: 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 the feeding consumable electrode 1, and the ratio of the melting rate of the first feeding electrode 101 to the diameter of the crystallizer 2 is 0.7; the ratio of the melting rate of the second feeding electrode 102 to the diameter of the crystallizer 2 is 0.4; when the third feeding electrode 103 is remelting, the ratio of the melting rate to the diameter of the crystallizer 2 is 0.2, and the flow rate of argon gas introduced into the first argon gas channel 104 is 10L / min; S4. Demolding of electroslag ingots.

[0041] The remelted ingot prepared in this embodiment has an upward protrusion at its top after the slag is removed. The diameter of the bottom of the protrusion is 320 mm and its height is about 1 mm.

[0042] Example 4 In Examples 1-3, graphite electrodes or consumable electrodes can be used as slag electrodes during the arc initiation and slag formation stage, or the slag electrode used in this example can be used.

[0043] In this embodiment, a novel slag-forming electrode was designed for the arc initiation and slag-forming stage, referring to... Figure 2 As shown, the slag-forming electrode 5 is provided with a second argon gas channel 501 that runs through it along its axial direction. This channel is used to introduce argon gas during the arc-starting slag-forming stage to promote the discharge of gas inside the slag pool during the slag-forming stage. This gas includes gas generated by the vaporization of condensate on the inner wall of the crystallizer. The slag-forming electrode 5 is made of pure iron electrode, and its melting point is higher than the slag-forming temperature and the melting point of the consumable electrode. This prevents the slag-forming electrode 5 from melting during the slag-forming stage and thus prevents the introduction of other impurities.

Claims

1. A feeding consumable electrode for electroslag remelting, characterized in that, The self-consumable feeding electrode includes a first feeding electrode (101), a second feeding electrode (102), and a third feeding electrode (103) arranged coaxially from bottom to top with decreasing diameters; wherein, the third feeding electrode (103) is provided with a first argon gas channel (104) running longitudinally through the interior, which is used to promote the droplets in the third feeding electrode (103) to pass through the slag pool (4) and drip into the molten metal pool.

2. The self-consumable electrode for electroslag remelting according to claim 1, characterized in that, The diameter of the third-stage feeding electrode (103) is 0.2 to 0.4 of the diameter of the crystallizer (2), and the diameter of the first argon channel (104) is 5 to 10 mm.

3. The feeding consumable electrode for electroslag remelting according to claim 2, characterized in that, The diameter of the first feeding electrode (101) is 80% to 90% of the diameter of the consumable electrode used for remelting, and the ratio of the diameter of the electrode to the diameter of the crystallizer (2) is 0.6 to 0.

8. The diameter of the second feeding electrode (102) is 0.4 to 0.6 of the diameter of the crystallizer (2).

4. The self-consumable electrode for electroslag remelting according to claim 3, characterized in that, The mass of the first feeding electrode (101) accounts for 6% to 10% of the total mass of the remelted ingot, the mass of the second feeding electrode (102) accounts for 3% to 6% of the total mass of the remelted ingot, and the mass of the third feeding electrode (103) accounts for 2% to 4% of the total mass of the remelted ingot.

5. A feeding compensation method for electroslag remelting, characterized in that, During the feeding stage, the feeding self-consumable electrode as described in any one of claims 1-4 is used for feeding. When the mass of the remelted ingot obtained inside the crystallizer (2) reaches 80%~88% of the total weight of the remelted ingot, the electroslag remelting enters the feeding stage; specifically: Replace the consumable electrode with a feeding consumable electrode (1). When remelting the third feeding electrode (103), argon gas is introduced into the first argon channel (104) at a flow rate of 5~10L / min.

6. The feeding method for electroslag remelting according to claim 1, characterized in that, The melting rate used for remelting the third section feeding electrode (103) is 0.05~0.2 times the diameter of the crystallizer (2).

7. The feeding method for electroslag remelting according to claim 1, characterized in that, The ratio of the melting rate of the first stage feeding electrode (101) to the diameter of the crystallizer (2) is 0.4 to 0.7; the ratio of the melting rate of the second stage feeding electrode (102) to the diameter of the crystallizer (2) is 0.2 to 0.

4.

8. An electroslag remelting apparatus, characterized in that, The device includes a crystallizer (2), a bottom water tank (3), a consumable electrode, and a feeding consumable electrode (1) as described in any one of claims 1-7, wherein the feeding consumable electrode (1) is used to replace the consumable electrode for remelting during the feeding stage.

9. The electroslag remelting apparatus according to claim 8, characterized in that, The device also includes a slag-forming electrode (5), which has a second argon gas channel (501) running through it along its axial direction, for introducing argon gas during the arc-starting slag-forming stage to promote the discharge of gas inside the slag pool (4) during the slag-forming stage; wherein, the slag-forming electrode (5) is made of pure iron electrode, and its melting point is greater than the slag-forming temperature and the melting point of the consumable electrode.

Images