Electroslag ingot anti-crack production method and device

Abstract

The present application relates to a kind of electric slag ingot crack prevention production method and device, the electric slag ingot crack prevention production method, including electric slag remelting stage, specifically including the following steps: step S1: before electric slag remelting starts, set the temperature difference of cooling water into bottom water tank and crystallizer as 15~20 ℃;Step S2: electric slag remelting is carried out;Step S3: with the progress of electric slag remelting stage, adjust the position of cooling water on the crystallizer and make the position move upwards with the rising of the melt pool in the crystallizer;Step S4: remove crystallizer;Wherein, in step S4, when removing crystallizer is completed, the lower end temperature of electric slag ingot is greater than 550 ℃, and the difference between the upper end temperature and the lower end temperature of electric slag ingot is less than or equal to 200 ℃.The present application reduces the influencing factors of large electric slag ingot crack to reduce the probability of large electric slag ingot crack.

Description

Technical Field

[0001] This invention relates to the field of electroslag remelting technology, specifically to a method and apparatus for producing electroslag ingots with crack prevention. Background Technology

[0002] 40NiCrMoV13-4 is a high-permeability steel with a low phase transformation temperature. In the production of large electroslag ingots, most of them are produced in fixed electroslag furnaces. After annealing using existing technology, especially after sawing off the ingot guard plate, a considerable number of electroslag ingots develop cracks at the bottom, resulting in scrap. The scrap rate is as high as 62.5%, resulting in huge economic losses.

[0003] Therefore, developing a crack-resistant production process for producing large 40NiCrMoV13-4 electroslag ingots using a stationary electroslag furnace is an urgent problem to be solved in this field. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method and apparatus for preventing cracks in electroslag ingots. The purpose is to change the production process and reduce the influencing factors that cause cracks in large electroslag ingots, thereby preventing cracks from forming in large electroslag ingots during the production process.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for preventing cracking in electroslag ingots includes an electroslag remelting stage, specifically comprising the following steps:

[0007] Step S1: Before electroslag remelting begins, set the temperature difference between the cooling water flowing into the bottom water tank and the crystallizer to 15℃~20℃, with the cooling water temperature flowing into the bottom water tank being higher than the cooling water temperature flowing into the crystallizer.

[0008] Step S2: Perform electroslag remelting;

[0009] Step S3: As the electroslag remelting stage proceeds, adjust the inlet position of the cooling water in the crystallizer so that the inlet position moves upward as the molten pool in the crystallizer rises.

[0010] Step S4: Remove the crystallizer;

[0011] In step S4, when the crystallizer is removed, the temperature at the lower end of the electroslag ingot is greater than 550°C, and the temperature difference between the upper and lower ends of the electroslag ingot is less than or equal to 300°C.

[0012] Preferably, in step S4, when the crystallizer is removed, the temperature of the lower end of the electroslag ingot is greater than 550°C, and the temperature difference between the upper end and the lower end of the electroslag ingot is less than or equal to 200°C.

[0013] The method for measuring the temperature of the upper and lower ends of the electroslag ingot is to use an infrared thermometer to measure the temperature values ​​at the upper and lower ends of the outer wall of the columnar electroslag ingot.

[0014] Analysis revealed that the main cause of the cracks was an inherent problem with the electroslag furnace production process. During electroslag furnace production, cooling water always enters from the bottom of the crystallizer and exits from the top. This means that the lower end of the electroslag ingot in the crystallizer is always strongly cooled. As a result, when the electroslag remelting is completed and the electroslag ingot leaves the crystallizer, there is a huge temperature difference between the upper and lower ends of the electroslag ingot, generating great thermal stress.

[0015] When the electroslag remelting process is completed and the electroslag ingot is removed from the crystallizer, the temperature difference between its upper and lower parts reaches 400℃, which can easily lead to stress cracking of the electroslag ingot. Taking a 40NiCrMoV13-4 electroslag ingot with a single weight of 13.5t, a diameter of 975mm, and a length of 2300mm as an example, its main components are as follows:

[0016] C 0.38-0.42 0.382 0.409 0.4 Si 0.23-0.37 0.325 0.350 0.33 Mn 0.20-0.35 0.296 0.307 0.32 P ≤0.010 0.003 0.004 0.004 S ≤0.005 0.001 0.002 0.002 Cr 0.90-1.20 0.974 0.970 1 Ni 3.1-3.5 3.31 3.29 3.31 Mo 0.45-0.70 0.483 0.494 0.493 Cu ≤0.10 0.040 0.045 0.03 Al ≤0.02 0.008 0.011 0.016 V 0.12-0.18 0.179 0.198 0.167 Ti ≤0.03 0.003 0.008 0.005 W ≤0.20 0.004 0.017 H ≤1.9 0.55 O ≤20 14 N 55

[0017] During conventional production, when the electroslag ingot leaves the crystallizer, the upper part has a temperature of about 850℃ and the lower part has a temperature of about 450℃, with a temperature difference of 400℃ between the upper and lower parts. At the same time, due to the dual cooling effect of the crystallizer and the bottom water tank at the bottom of the electroslag ingot, coupled with the long smelting time of the electroslag ingot, the cooling effect at the bottom of the electroslag ingot is too strong, and the solid shrinkage at the bottom of the electroslag ingot is large. Tensile stress is generated in the center part of the electroslag ingot, causing deformation of the electroslag ingot. When the amount of deformation exceeds the elongation at that temperature, cracks will occur.

[0018] Based on the above analysis, it was found that this invention uses different cooling effects to reduce the temperature difference between the upper and lower ends of the electroslag ingot. For this method, the cooling water injection point is the strong cooling zone. As the cooling water enters the crystallizer, it gradually absorbs heat and heats up, reducing the cooling effect and implementing weak cooling in subsequent areas. By adjusting the cooling water inflow point, the cooling conditions of the electroslag ingot are changed, causing the strong cooling zone (cooling water inflow point) to move upwards with the molten pool, providing a relatively strong cooling effect to the overheated parts. This reduces the temperature difference between the upper and lower ends of the electroslag ingot, decreasing thermal stress. Furthermore, the relatively strong cooling effect causes the outer layer of the electroslag ingot to solidify rapidly, maintaining the ingot's shape. After rapid solidification of the outer layer, the strong cooling zone moves upwards (the cooling water inflow point becomes the strong cooling zone). As the water flows downwards, it gradually absorbs heat and the temperature rises. This continues with relatively weak cooling at this point. The relatively weak cooling rate slows down the solidification rate in the middle of the electroslag ingot. During solidification at the lower end, it receives feed from the upper melt pool at the axial direction. Simultaneously, the lower cooling rate reduces thermal stress and increases the water temperature in the bottom water tank, reducing its cooling effect. This ensures that the temperature at the lower end of the electroslag ingot at the end of the electroslag remelting stage is higher than the temperature at the lower end of existing electroslag ingots at the end of the electroslag remelting stage, reducing thermal stress and preventing a large temperature difference between the lower and upper ends due to excessive temperature drop. At the end of electroslag ingot production, the temperature difference between the upper and lower parts of the electroslag ingot is maintained below 200℃, effectively reducing thermal stress and crack formation.

[0019] Furthermore, it also includes a heat preservation stage, with a heat preservation temperature of 550℃±10℃ and a heat preservation time of ≥10h.

[0020] The electroslag ingot is removed from the crystallizer and immediately hoisted into the annealing furnace for heat preservation. The electroslag ingot is placed in the annealing furnace preheated to 550℃±10℃ to slowly dissipate heat. The electroslag ingot is kept in the annealing furnace for more than 10 hours.

[0021] The annealing furnace is preheated to 550℃±10℃. When the electroslag ingot production is completed, the temperature at the bottom is higher than 550℃. This allows for a temperature reduction margin during the hoisting of the electroslag ingot and ensures that the electroslag ingot is mostly pearlite during the heat preservation stage, avoiding the formation of bainite and martensite, reducing the coexistence of multiple structures, and reducing structural stress.

[0022] Therefore, in addition to reducing / eliminating thermal stress by maximizing the temperature difference between the two ends of the electroslag ingot through heat conduction, the heat preservation stage also specifically prevents the generation of structural stress. This is because during the production of the electroslag ingot, the lower end is cooled first. During solidification, the supercooled austenite transforms into different structures at different temperatures at the upper and lower ends. This can easily lead to greater structural stress during annealing due to the different shrinkage and expansion states of these structures, increasing the probability of crack formation. Even if the temperature is raised to a sufficient level during annealing and then slowly cooled, it cannot compensate for the cracks that have already formed. Therefore, it is necessary to heat preservation before annealing for a sufficient duration to allow the structural transformation to become more uniform and reduce structural stress before proceeding with annealing.

[0023] Furthermore, it also includes an annealing stage, which specifically includes the following steps:

[0024] Step 1: Increase the temperature at a rate of 50℃ / h~65℃ / h until it reaches 780℃±10℃;

[0025] Step 2: Insulate for at least 20 hours;

[0026] Step 3: Cool down at a rate of ≤10℃ / h, and then cool in a sheltered place after the temperature has dropped below 100℃.

[0027] During the windproof cooling process, hardness testing is performed. If the hardness is below 300HB, the electroslag ingot is cooled to room temperature and packaged. If the hardness is above 300HB, it is hoisted back to the annealing furnace for re-annealing.

[0028] This annealing step reduces the heating and cooling rates to ensure a uniform pearlitic structure during the annealing stage. Compared to the prior art, the holding and annealing stages of this invention are equivalent to two annealing processes. The holding stage is used to prevent crack formation, while the annealing stage is used to improve processing performance, thereby improving product quality.

[0029] An anti-crack production device for electroslag ingots includes an electroslag furnace. The electroslag furnace includes a casting section for depositing molten metal, a mechanical transmission section for holding consumable electrodes, and a power supply section for providing an electrical circuit. The casting section includes a bottom water tank and a crystallizer. Multiple water inlet pipes are arranged along the height of the crystallizer, and water outlet pipes are respectively provided at the lower and upper ends of the crystallizer. As the molten pool in the crystallizer rises, cooling water is introduced into the crystallizer through the higher water inlet pipes. After entering the crystallizer, the cooling water flows upward and downward respectively to control the cooling state of the electroslag ingot.

[0030] The present invention provides an anti-crack production device for electroslag ingots, wherein the crystallizer of the electroslag furnace has an adjustable cooling water inflow position, which can reduce the temperature difference between the upper and lower ends of the electroslag ingot.

[0031] Furthermore, both ends of the multiple water inlet pipes are respectively connected to a crystallizer and a valve. The flow of cooling water in different water inlet pipes is regulated by the valve. The valve includes a housing, a valve core, and a drive motor. The side wall of the housing is connected to multiple water inlet pipes. The valve core is slidably connected inside the housing. The valve core is a tubular body. The side wall of the valve core is provided with a spiral water inlet. The cooling water supply pipe passes through the housing and connects to the valve core. A drive shaft is coaxially provided on the valve core. The drive shaft is driven by the drive motor outside the housing to make the valve core rotate inside the housing. When the valve core rotates, cooling water flows in the water inlet pipe directly opposite the water inlet.

[0032] There are several options for adjusting the cooling water injection position. For example, each inlet pipe can be configured as a tubular body with a valve on it. In this case, by adjusting the opening and closing of different valves, the inlet pipe can be raised as the molten pool rises. Alternatively, each inlet pipe can be connected to the cooling water supply pipe via a selective valve. When it is necessary to raise the cooling water inflow channel, the lower cooling water supply pipe can be closed while the upper cooling water supply pipe is opened. Both options can achieve the required solution.

[0033] However, the above structure requires extremely precise control, and the valve control points are numerous and complex. Insufficient precision can easily lead to fluctuations in the cooling effect of the cooling water, so further improvements are needed.

[0034] This solution was selected as the preferred one among various methods for regulating the flow of cooling water. The continuous change of the water inlet pipe can be achieved by driving the valve core to rotate with the drive motor. The adjustment needs can be met by simply controlling the rotation speed of the drive motor. Compared with other solutions that require multi-point adjustment, this solution is easier to control, the cooling water flow changes smoothly, the accuracy is higher, there are fewer controls, and the operation is simpler.

[0035] Furthermore, the upward-flowing cooling water flow rate is greater than the downward-flowing cooling water flow rate.

[0036] Compared to the previous method of designating the cooling water injection point as the strong cooling zone and the rest as the weak cooling zone, the method of creating a flow difference between the upward and downward flowing cooling water significantly increases the gap between strong and weak cooling. The smaller flow rate of the downward flowing cooling water results in faster heat absorption and temperature rise, further reducing the cooling effect on the cooling water injection point. This ensures that the temperature difference between the upper and lower ends of the electroslag ingot remains within the allowable range after the electroslag remelting stage, or even decreases further.

[0037] Furthermore, the inner diameter of the water outlet pipe at the lower end of the crystallizer is smaller than the inner diameter of the water outlet pipe at the upper end of the crystallizer.

[0038] This is the specific method of the previous scheme, which determines the flow difference based on the diameter of the outlet pipe.

[0039] Furthermore, both the water outlet pipe at the lower end of the crystallizer and the water outlet pipe at the upper end of the crystallizer are equipped with shut-off valves that can adjust the opening degree.

[0040] Further optimization of the scheme allows for the adjustment of the flow rate difference between the water outlet pipe at the lower end and the water outlet pipe at the upper end of the crystallizer, thus enabling it to adapt to the production of electroslag ingots of different diameters and the control of different temperature differences.

[0041] Furthermore, the width of the water inlet on the valve core is greater than or equal to the width or diameter of the water inlet pipe, and the sum of the cross-sections of the water outlet pipes at the lower end and upper end of the crystallizer is less than the cross-section of the cooling water supply pipe.

[0042] Compared to a single water inlet pipe, the water outlet is wider and the cooling water supply pipe has a larger cross-section, ensuring a sufficient supply of cooling water.

[0043] Furthermore, the water inlet rotates around the central axis of the valve core by an angle of 90° to 270°.

[0044] Furthermore, the water inlet rotates 180° around the central axis of the valve core.

[0045] The beneficial effects of the present invention through the above technical solution are as follows:

[0046] This invention changes the production process, fundamentally reducing the factors influencing crack formation in large electroslag ingots from the production stage, thereby reducing the probability of crack formation in large electroslag ingots and resulting in significant economic benefits.

[0047] This invention modifies the annealing process by adding a heat preservation stage, which enables the electroslag ingot to achieve temperature uniformity at both ends before annealing, and makes the microstructure transformation more consistent during heat preservation, eliminating thermal stress and preventing annealing cracking.

[0048] This invention modifies the structure of the crystallizer to match the production process of electroslag ingots. The crystallizer has an adjustable cooling water inflow position, which can reduce the temperature difference between the upper and lower ends of the electroslag ingot. It also requires minimal equipment modification and can satisfy the production process of this invention as well as be applied to existing production processes.

[0049] This invention adjusts the structure of the valve to allow for smooth and continuous adjustment of the cooling water inflow position, making operation simple. Attached Figure Description

[0050] Figure 1 This refers to the annealing process of the electroslag ingot in Embodiment 1 of the present invention;

[0051] Figure 2 This is the crack state of the electroslag ingot in Embodiment 1 of the present invention;

[0052] Figure 3This refers to the annealing process of the electroslag ingot in Embodiment 2 of the present invention;

[0053] Figure 4 This is the crack state of Embodiment 2 of the present invention;

[0054] Figure 5 This is a schematic diagram of the electroslag furnace of the present invention;

[0055] Figure 6 This is a cross-sectional front view of the crystallizer of the present invention;

[0056] Figure 7 This is a schematic diagram of the valve core of the present invention.

[0057] The attached diagram is labeled as follows: 1. Bottom water tank; 2. Crystallizer; 3. Copper liner; 4. Cooling sleeve; 5. Cooling channel; 6. Water inlet pipe; 7. Valve; 8. Shell; 9. Valve core; 10. Drive motor; 11. Cooling water supply pipe; 12. Water inlet; 13. Drive shaft; 14. Water outlet pipe; 15. Shut-off valve. Detailed Implementation

[0058] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0059] Example 1:

[0060] A method for producing anti-crack electroslag ingots includes two stages: electroslag remelting and annealing. Immediately after the electroslag remelting stage, the electroslag ingot is hoisted into an annealing furnace for annealing. The relationship between temperature and time during the annealing process is as follows: Figure 1 As shown, in this embodiment, 16 electroslag ingots were manufactured. Customer feedback indicated that 10 of the ingots had cracks at the bottom, resulting in a scrap rate of 62.5%. The cracks at the bottom of the electroslag ingots are shown in the image below. Figure 2 As shown.

[0061] Example 2:

[0062] A method for producing anti-crack electroslag ingots includes three stages: electroslag remelting, heat preservation, and annealing. The heat preservation stage involves taking the electroslag ingot out of the crystallizer 2 and immediately hoisting it into the annealing furnace for heat preservation. The electroslag ingot is placed in the annealing furnace preheated to 550℃±10℃ to slowly dissipate heat, and the electroslag ingot is kept at this temperature in the annealing furnace for more than 10 hours.

[0063] The relationship between temperature and time in the annealing stage is as follows: Figure 3 As shown, it includes the following steps:

[0064] Step 1: Heat the annealing furnace to 780℃±10℃ at a heating rate of 50℃ / h~65℃ / h;

[0065] Step 2: Keep warm for at least 20 hours;

[0066] Step 3: After cooling the electroslag ingot to below 100℃ at a cooling rate of less than 10℃ / h, remove it from the furnace, cool it in a sheltered environment, and perform a hardness test. If the hardness is less than 300HB, cool the electroslag ingot to room temperature and package it. If the hardness is greater than 300HB, hoist it back to the annealing furnace for re-annealing.

[0067] This embodiment is an improvement on Embodiment 1, addressing the issues encountered with the product in Embodiment 1. After the improvement process, 20 electroslag ingots were produced. Customer feedback indicated that 6 of the ingots had cracks at the bottom, resulting in a scrap rate of 30%. The cracks at the bottom of the electroslag ingots are as follows: Figure 4 As shown.

[0068] Example 3:

[0069] A method for preventing cracking in electroslag ingots includes an electroslag remelting stage, specifically comprising the following steps:

[0070] Step S1: Before electroslag remelting begins, set the temperature difference between the cooling water supplied to the bottom water tank and the crystallizer to be 15℃~20℃;

[0071] Step S2: Perform electroslag remelting;

[0072] Step S3: As the electroslag remelting stage proceeds, adjust the inlet position of the cooling water in the crystallizer so that the inlet position moves upward as the molten pool in the crystallizer rises.

[0073] Step S4: Remove the crystallizer;

[0074] In step S4, when the crystallizer is removed, the temperature at the lower end of the electroslag ingot is greater than 550°C, and the temperature difference between the upper and lower ends of the electroslag ingot is less than or equal to 200°C.

[0075] It also includes a heat preservation stage and an annealing stage. The heat preservation stage involves taking the electroslag ingot out of the crystallizer 2 and immediately hoisting it into the annealing furnace for heat preservation. The electroslag ingot is placed in the annealing furnace preheated to 550℃±10℃ to slowly dissipate heat. The electroslag ingot is kept in the annealing furnace for more than 10 hours.

[0076] The annealing stage includes the following steps:

[0077] Step 1: Heat the annealing furnace to 780℃±10℃ at a heating rate of 50℃ / h~65℃ / h;

[0078] Step 2: Keep warm for at least 20 hours;

[0079] Step 3: After cooling the electroslag ingot to below 100℃ at a cooling rate of less than 10℃ / h, remove it from the furnace, cool it in a sheltered environment, and perform a hardness test. If the hardness is less than 300HB, cool the electroslag ingot to room temperature and package it; if the hardness is greater than 300HB, hoist it back to the annealing furnace for re-annealing.

[0080] This embodiment is an improvement on embodiment two. In this embodiment, 26 electroslag ingots were produced. Customer feedback indicated that no cracks appeared at the bottom of any of the electroslag ingots, and the quality of the electroslag ingots was good.

[0081] like Figure 5 As shown, an anti-crack production device for electroslag ingots includes an electroslag furnace for electroslag remelting and an annealing furnace for heat preservation annealing. Similar to a conventional electroslag furnace, the electroslag furnace includes a melting and casting section, a mechanical transmission section, and a power supply section. The melting and casting section includes a bottom water tank 1 and a crystallizer 2. The crystallizer 2 includes a cylindrical copper liner 3 and a cylindrical cooling sleeve 4. The outer wall of the copper liner 3 is fixedly connected to the inner wall of the cooling sleeve 4. The interior of the cooling sleeve 4 is provided with a spiral cooling channel 5. The difference is that, as shown in the figure... Figure 6 As shown, multiple water inlet pipes 6 are arranged along the height direction of the crystallizer 2, including but not limited to multiple water pipes arranged along the height direction of the crystallizer and connected to the cooling sleeve 4. In this embodiment, the water inlet pipe 6 is a rectangular pipe with multiple partitions inside, forming multiple channels arranged sequentially from top to bottom. Each of the multiple water inlet pipes 6 is connected to the cooling sleeve 4 at one end and to a valve 7 at the other end. The valve 7 controls the flow of cooling water in one or two adjacent water inlet pipes 6, while the other water inlet pipes are in a closed state.

[0082] The valve 7 includes a housing 8, a valve core 9, and a drive motor 10. The housing 8 is a cylindrical body, and multiple water inlet pipes 6 are connected to the side wall of the housing 8. The valve core 9 is installed inside the housing 8. Figure 7 As shown, the valve core 9 is a tubular body. The outer wall of the valve core 9 slides in contact with the inner wall of the housing 8. The cooling water supply pipe 11 passes through the housing 8 and connects to the valve core 9. A spiral water inlet 12 is provided on the side wall of the valve core 9. The water inlet 12 rotates around the central axis of the valve core 9 by an angle of 90° to 270°, i.e., less than one revolution, to avoid the water inlet 12 connecting multiple (far apart) water inlet pipes 6 at one time. In this embodiment, 180° is selected. A drive shaft 13 is provided at the end of the valve core 9 away from the cooling water supply pipe 11. The drive shaft 13 passes through the housing 8 and is driven to rotate by the drive motor 10 outside the housing 8. When the drive shaft When the valve core 9 rotates, it rotates around its central axis and slides relative to the housing. Cooling water flows in the water inlet pipe 6, which is directly opposite the water inlet 12. As the valve core 9 rotates, the water inlet 12 and the water inlet pipe 6 become higher and higher, so that the cooling water injection position moves upward with the rise of the melting pool, which is used to control the cooling state of the electroslag ingot. The lower end and the upper end of the crystallizer 2 are respectively provided with water outlet pipes 14. Both the lower end water outlet pipe 14 and the upper end water outlet pipe 14 of the crystallizer 2 are provided with shut-off valves 15 that can adjust the opening. The inner diameter of the lower end water outlet pipe 14 of the crystallizer 2 is smaller than the inner diameter of the upper end water outlet pipe 14 of the crystallizer 2.

[0083] The width of the water inlet 12 on the valve core 9 is greater than or equal to the width or diameter of the water inlet pipe 6, and the sum of the cross-sections of the water outlet pipes 14 at the lower end of the crystallizer 2 and the upper end of the crystallizer 2 is less than the cross-section of the cooling water supply pipe 11.

[0084] During operation, the mechanical transmission part clamps the consumable electrode and extends it into the melting and casting part for electroslag remelting. Initially, the lower end of the water inlet 12 is connected to the lowest water inlet pipe 6. At this time, all the cooling water flows upward from the bottom of the crystallizer 2 and is discharged from the water outlet pipe 14 at the upper end of the crystallizer 2. During the electroslag remelting stage, as the consumable electrode is consumed, the molten pool gradually rises. The drive motor 10 drives the valve core 9 to rotate, causing the position of the water inlet 12 on the valve core 9 connected to the water inlet pipe 6 to move upward, that is, the position of the cooling water inlet moves upward. At this time, a portion of the cooling water flows upward (flow rate). A larger portion of the cooling water flows upward and is discharged through the outlet pipe 14 at the upper end of the crystallizer 2, while another portion flows downward (with a smaller flow rate) and is discharged through the outlet pipe 14 at the lower end of the crystallizer 2. Because both the outlet pipe 14 at the lower end of the crystallizer 2 and the outlet pipe 14 at the upper end of the crystallizer 2 are equipped with shut-off valves 15 that can adjust the opening, and the inner diameter of the outlet pipe 14 at the lower end of the crystallizer 2 is smaller than that at the upper end of the crystallizer 2, more cooling water flows upward than downward, resulting in a stronger cooling effect. Therefore, it is possible to cool the electroslag ingot, while reducing the temperature difference between the upper and lower ends of the electroslag ingot and reducing thermal stress.

[0085] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various modifications can be made to the technical solutions of the present invention without departing from the spirit of the present invention or the scope of disclosure.

Claims

1. An electroslag ingot anti-crack production apparatus, used to realize an anti-crack production method for electroslag ingots, the production method including an electroslag remelting stage, the production method specifically including the following steps: Step S1: Before electroslag remelting begins, set the temperature difference between the cooling water entering the bottom water tank and the crystallizer to 15℃~20℃; Step S2: Perform electroslag remelting; Step S3: As the electroslag remelting stage progresses, adjust the position of the cooling water entering the crystallizer so that the position moves upward as the molten pool inside the crystallizer rises; Step S4: Remove the crystallizer; wherein, in step S4, when the crystallizer is removed, the temperature of the lower end of the electroslag ingot is greater than 550℃, and the temperature difference between the upper end and the lower end of the electroslag ingot is less than or equal to 300℃; The production apparatus includes an electroslag furnace, which includes a casting section for depositing molten metal, a mechanical transmission section for holding consumable electrodes, and a power supply section for providing an electrical circuit. The casting section includes a bottom water tank (1) and a crystallizer (2). The crystallizer (2) is characterized by having multiple water inlet pipes (6) arranged along the height direction of the crystallizer (2), and water outlet pipes (14) respectively provided at the lower end and the upper end of the crystallizer (2). As the molten pool in the crystallizer (2) rises, cooling water is introduced into the crystallizer (2) through the water inlet pipes (6) at a higher position. After entering the crystallizer (2), the cooling water flows upward and downward respectively to control the cooling state of the electroslag ingot. Both ends of the multiple water inlet pipes (6) are respectively connected to the crystallizer (2) and the valve (7). The flow of cooling water in the different water inlet pipes (6) is regulated by the valve (7). The valve (7) includes a housing (8), a valve core (9) and a drive motor (10). The side wall of the housing (8) is connected to multiple water inlet pipes (6). The valve core (9) is slidably connected inside the housing (8). The valve core (9) is a tubular body. The side wall of the valve core (9) is provided with a spiral water inlet (12). The cooling water supply pipe (11) passes through the housing (8) and connects to the valve core (9). The valve core (9) is coaxially provided with a drive shaft (13). The drive shaft (13) is driven by the drive motor (10) outside the housing (8) to make the valve core (9) rotate inside the housing (8). When the valve core (9) rotates, cooling water flows in the water inlet pipe (6) opposite to the water inlet (12).

2. The anti-crack production device for electroslag ingots according to claim 1, characterized in that, The production method also includes a heat preservation stage, with a heat preservation temperature of 550℃±10℃ and a heat preservation time of ≥10h.

3. The anti-crack production device for electroslag ingots according to claim 1, characterized in that, The production method also includes an annealing stage, which specifically includes the following steps: Step 1: Heating, with a heating rate of 50℃ / h~65℃ / h, heating to 780℃±10℃; Step 2: Holding, holding time ≥20h; Step 3: Cooling, with a cooling rate ≤10℃ / h, cooling to below 100℃ and then cooling in a sheltered environment; wherein, during the sheltered cooling process, hardness testing is performed, if the hardness is lower than 300HB, the electroslag ingot is cooled to room temperature and packaged; if the hardness is higher than 300HB, it is hoisted back to the annealing furnace for re-annealing.

4. The anti-crack production device for electroslag ingots according to claim 1, characterized in that, The flow rate of cooling water flowing upward is greater than the flow rate of cooling water flowing downward.

5. The anti-crack production device for electroslag ingots according to claim 4, characterized in that, The inner diameter of the water outlet pipe (14) at the lower end of the crystallizer (2) is smaller than the inner diameter of the water outlet pipe (14) at the upper end of the crystallizer (2).

6. The anti-crack production device for electroslag ingots according to claim 4, characterized in that, Both the water outlet pipe (14) at the lower end of the crystallizer (2) and the water outlet pipe (14) at the upper end of the crystallizer (2) are equipped with shut-off valves (15) that can adjust the opening degree.

7. The anti-crack production device for electroslag ingots according to claim 1, characterized in that, The width of the water inlet (12) on the valve core (9) is greater than or equal to the width or diameter of the water inlet pipe (6), and the sum of the cross sections of the water outlet pipe (14) at the lower end of the crystallizer (2) and the upper end of the crystallizer (2) is less than the cross section of the cooling water supply pipe (11).

8. The anti-crack production device for electroslag ingots according to claim 1, characterized in that, The water inlet (12) rotates around the central axis of the valve core (9) at an angle of 90°~270°.

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