Large nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot and heat top sealing process thereof
By using a multi-stage hot capping process that controls the melting rate, the problem of heat input-output imbalance during the remelting of large ingot nickel-based alloys was solved, achieving efficient solidification quality control, reducing defect risks, and improving yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-03-24
AI Technical Summary
In the existing traditional hot capping process, the heat input-output balance is easily disrupted during the remelting of large ingot nickel-based alloys, and the feedback speed of melting rate changes is slow, resulting in a high risk of solidification defects such as black spots, porosity, and cracks, and a low yield.
A multi-stage melting rate control method is adopted, including steps of reducing, stabilizing, increasing and reducing the melting rate. By controlling the remaining weight of the electrode ingot and the arc power, the melting rate change during the hot capping stage is optimized to ensure the temperature stability of the electrode end and the depth of the molten pool.
It effectively reduces the depth of shrinkage cavities, increases the yield by 5-10%, reduces the risk of defects, and improves the yield and microstructure density of large nickel-based alloy vacuum consumable ingots.
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Figure CN121718709A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of special metallurgical technology, and in particular to a large nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot and its hot capping process. Background Technology
[0002] Vacuum self-consuming remelting (VAR) technology has become a core technology for producing high-end metal materials for key equipment due to its advantages of precise control of alloy composition and significant reduction of gas and inclusion content in a vacuum environment.
[0003] With the rapid development of the high-end energy and power equipment field, the size of vacuum consumable remelted alloy ingots has gradually increased from... Upgraded to even Compared with small and medium-sized ingots, large-sized nickel-based alloys face more severe challenges in solidification quality due to their larger cross-sectional area and deeper molten pool: slower heat dissipation, longer solidification time, more difficulty in controlling the thermal gradient, and a greater likelihood of defects such as macroscopic segregation, deep shrinkage cavities, and black spots, which seriously affect yield and service performance.
[0004] Hot capping is the final stage of the vacuum arc remelting process. Essentially, it involves precisely controlling the arc power and molten pool heat input to ensure sufficient feeding of the large ingot head during slow solidification, preventing macroscopic shrinkage cavities and porosity defects. Simultaneously, it promotes the floating of inclusions and the expulsion of gases, thereby ensuring the density and chemical uniformity of the ingot material. A good hot capping process requires a balance between two aspects: first, providing sufficient heat to maintain the molten pool so that the feeding molten metal can fully fill the voids created by solidification shrinkage; and second, avoiding overheating that leads to coarse grains, increased segregation, or the formation of black spots.
[0005] However, existing traditional hot capping processes mostly employ experience-based single melting rate control modes, such as linear power reduction, step power reduction, or fixed-rate cooling. Under ideal conditions, these methods can slowly reduce the melting rate (quantitative data will be supplemented later) to control the depth of shrinkage cavities and the solidification quality of the capping section. However, the heat input required for remelting large ingots of nickel-based alloys is much higher than that for conventional ingots. Even small changes in current and voltage can lead to a rapid imbalance between heat input and output. Furthermore, the feedback speed of melting rate changes in large ingots is slow. Often, an abnormal decrease in melting rate is only detected after the temperature at the electrode tip has already fallen below the critical value. At this point, effective intervention methods have been lost, the melting rate decreases rapidly, and arc interruption may even occur. This leads to an increase in the depth of solidification shrinkage cavities, a decrease in yield, and a significant increase in the risk of black spots, porosity, and cracks. Summary of the Invention
[0006] Based on the above analysis, the present invention aims to provide a large-scale nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot and its hot capping process, thereby reducing solidification defects in large-scale vacuum consumable ingots and improving yield.
[0007] On one hand, this invention provides a hot capping process for large nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingots. The process involves vacuum consumable remelting of the electrode ingot, followed by an arc-starting stage and a stable melting stage. When the remaining weight of the electrode ingot is 8%-15% of the total weight, it enters the hot capping stage. The process includes the following steps:
[0008] S1: Reduce power to decrease the melting rate from the melting rate during the stable melting stage to the preset melting rate;
[0009] S2: Maintain the preset melting rate, then increase the power to no more than 0.1 kg / min. 2 The rate of increase in melting speed is maintained after reaching the target melting speed;
[0010] S3: Then at a speed not exceeding 0.8 kg / min 2 The melting rate is reduced, and when the weight of the remaining electrode ingot is less than 3%, the power supply is stopped, the hot capping stage ends, and after solidification, a nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is obtained.
[0011] Furthermore, the diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is ≥660mm.
[0012] Furthermore, in step S1, the preset melting rate is 1 / 5 to 1 / 3 of the melting rate during the stable melting stage.
[0013] Furthermore, in step S2, the increased melting rate is no higher than 2 / 3 of the melting rate during the stable melting stage, and the duration of maintaining the increased melting rate accounts for 8% to 15% of the total heat capping time.
[0014] Furthermore, the time for maintaining the preset melting rate accounts for 30% to 50% of the total duration of the hot capping stage.
[0015] Furthermore, the hot capping stage accounts for 10% to 25% of the total melting time.
[0016] Furthermore, the diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 920 mm, the melting rate of the stable melting stage is 7-12 kg / min, and the weight of the hot capping is 960-1800 kg.
[0017] Furthermore, the diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 810 mm, the melting rate of the stable melting stage is 4-9 kg / min, and the weight of the hot capping is 800-1500 kg.
[0018] Furthermore, the diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 660 mm, the melting rate of the stable melting stage is 3-8 kg / min, and the weight of the hot capping is 480-900 kg.
[0019] On the other hand, the present invention provides a large nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot, which is prepared by the hot capping process described in the present invention.
[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:
[0021] 1. This invention proposes multi-stage controlled melting rate. After the stable melting stage, the hot capping stage begins. First, the melting rate is reduced from the stable melting stage to a preset value, and after stabilizing for a period of time, it is reduced again at a rate not exceeding 0.1 kg / min. 2 The melting rate is increased and then decreased. When the weight of the remaining electrode ingot is less than 3%, the power supply is stopped, and the hot sealing stage ends. The resulting nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is free from defects such as black spots, porosity, and cracks.
[0022] 2. The method provided by this invention is applicable to vacuum consumable steel and nickel-based alloys of all specifications. However, for small ingots, the feeding time is short, and changes in the melting rate have little effect on the electrode tip temperature, and adjustments to the hot capping process have a relatively small impact. But for large ingots, such as... For the above ingot types, especially for the low-melting-rate nickel-based alloy consumable remelting process, the optimized hot capping process reduces the shrinkage depth by more than 1 / 2 and increases the yield by 5-10%, which has great economic value.
[0023] 3. In this invention, the melting rate is reduced to a preset melting rate, which is 1 / 5 to 1 / 3 of the stable melting stage. This reduces the depth of the molten pool and improves the density of the microstructure in the early stage of the hot capping phase. If the melting rate is further reduced to below 1 / 5, the electrode tip temperature may be too low, posing a risk of arc interruption. The purpose of subsequently increasing the melting rate or keeping it constant is to maintain a certain molten pool depth and avoid the risk of shrinkage cavities and porosity caused by dendrite bridging at the bottom of the molten pool after a power outage.
[0024] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description
[0025] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.
[0026] Figure 1 The hole shrinkage depth of the hot sealing process is shown in the following figures from left to right: Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3.
[0027] Figure 2 The probability of black spot formation in the hot sealing process is shown in the following figures from left to right: Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3.
[0028] Figure 3 The secondary dendrite spacing of the hot capping process is shown in the following figures from left to right: Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3.
[0029] Figure 4 The results of longitudinal section inspection in Example 2;
[0030] Figure 5 The results are from the longitudinal section test of Comparative Example 4. Detailed Implementation
[0031] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.
[0032] Vacuum self-consuming remelting (VAR) technology has become a core technology for producing high-end metal materials for key equipment due to its advantages of precise control of alloy composition and significant reduction of gas and inclusion content in a vacuum environment.
[0033] With the rapid development of the high-end energy and power equipment field, the size of vacuum consumable remelted alloy ingots has gradually increased from... Upgraded to even Compared to small and medium-sized ingots, large-ingot nickel-based alloys face more severe challenges in solidification quality due to their larger cross-sectional area and deeper molten pool: slower heat dissipation, longer solidification time, and greater difficulty in controlling the thermal gradient. Large-ingot nickel-based alloys are more prone to defects such as macroscopic segregation, deep shrinkage cavities, and black spots, which seriously compromise yield and service performance.
[0034] Hot capping is the final stage of the vacuum arc remelting process. Its essence is to ensure that the head of the large ingot is fully fed during the slow solidification process by precisely controlling the arc power and the heat input of the molten pool, so as to avoid the formation of defects such as macroscopic shrinkage cavities and porosity. At the same time, it promotes the floating of inclusions and the discharge of gas, thereby ensuring the density and chemical composition uniformity of the ingot body material.
[0035] However, existing traditional hot capping processes mostly employ experience-based single melting rate control modes, such as linear power reduction, step power reduction, or fixed-rate cooling. Under ideal conditions, these methods can slowly reduce the melting rate (quantitative data will be supplemented later) to control the depth of shrinkage cavities and the solidification quality of the capping section. However, the heat input required for remelting large ingots of nickel-based alloys is much higher than that for conventional ingots. Even small changes in current and voltage can lead to a rapid imbalance between heat input and output. Furthermore, the feedback speed of melting rate changes in large ingots is slow. Often, an abnormal decrease in melting rate is only detected after the temperature at the electrode tip has already fallen below the critical value. At this point, effective intervention methods have been lost, the melting rate decreases rapidly, and arc interruption may even occur. This leads to an increase in the depth of solidification shrinkage cavities, a decrease in yield, and a significant increase in the risk of black spots, porosity, and cracks.
[0036] Therefore, this invention provides a hot capping process for large nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingots. The process involves vacuum consumable remelting of the electrode ingot, followed by an arc-starting stage and a stable melting stage. When the remaining weight of the electrode ingot is 8%-15% of the total weight, it enters the hot capping stage. The process includes the following steps:
[0037] S1: Reduce power to decrease the melting rate from the melting rate during the stable melting stage to the preset melting rate;
[0038] S2: Maintain the preset melting rate, then increase the power to no more than 0.1 kg / min. 2 The rate of increase in melting speed is maintained after reaching the target melting speed;
[0039] S3: Then at a speed not exceeding 0.8 kg / min 2 The melting rate is reduced, and when the weight of the remaining electrode ingot is less than 3%, the power supply is stopped, the hot capping stage ends, and after solidification, a nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is obtained.
[0040] Compared with existing technologies, this invention proposes multi-stage control of the melting rate. After the stable melting stage, the hot capping stage begins. First, the melting rate is reduced from the stable melting stage to a preset value. After stabilizing for a period of time, the melting rate is then reduced to no more than 0.1 kg / min. 2 The melting rate is increased and maintained for a period of time, and then the melting rate is reduced. When the weight of the remaining electrode ingot is less than 3%, the power supply is stopped, and the hot capping stage ends. The resulting nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is free from defects such as black spots, porosity, and cracks.
[0041] Specifically, the diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is ≥660mm.
[0042] It should be noted that the method provided by this invention is applicable to all specifications of steel and nickel-based alloys in vacuum consumable metals. However, for small ingots, the feeding time is short, and changes in the melting rate have little effect on the electrode tip temperature, and adjustments to the hot capping process have a relatively small impact. But for large ingots, such as... For the above ingot types, especially for the low-melting-rate nickel-based alloy consumable remelting process, the optimized hot capping process reduces the shrinkage depth by more than 1 / 2 and increases the yield by 5-10%, which has great economic value.
[0043] In this invention, the diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot can be [missing information]. or
[0044] Specifically, in step S1, the preset melting rate is 1 / 4 to 1 / 3 of the melting rate during the stable melting stage.
[0045] It should be noted that in this invention, reducing the melting rate to a preset melting rate, which is 1 / 5 to 1 / 3 of the stable melting stage, reduces the depth of the molten pool and improves the density of the microstructure in the early stage of hot capping. If the melting rate is further reduced to below 1 / 5, the electrode tip temperature may be too low, posing a risk of arc interruption. The purpose of maintaining a constant melting rate thereafter is to maintain a certain molten pool depth and avoid the risk of shrinkage cavities and porosity caused by dendrite bridging at the bottom of the molten pool after a power outage.
[0046] Specifically, in step S2, the increased melting rate is no higher than 2 / 3 of the melting rate during the stable melting stage.
[0047] It should be noted that after maintaining the preset melting rate for a period of time, the power is increased, thereby increasing the melting rate. The increased melting rate should not exceed 2 / 3 of the cooling rate during the melting stage. This allows the undiluted molten metal at the top to receive a small amount of additional heat input, maintaining a certain level of fluidity and filling the tiny gaps generated during the solidification process. If the melting rate exceeds 2 / 3 of the melting rate during the stable stage, it will lead to excessively high molten pool temperature and excessive depth, resulting in defects such as porosity and inclusions.
[0048] Specifically, the time for maintaining the preset melting rate accounts for 30% to 50% of the total duration of the hot capping stage.
[0049] It should be noted that maintaining the preset melting rate for 30% to 50% of the total time of the hot capping stage allows the molten pool after the melting rate reduction to smoothly transition from a deep pool with a large temperature gradient in the stable melting stage to a shallow pool with a uniform temperature gradient. If the holding time is less than 30%, the molten pool depth and temperature distribution will not stabilize before the melting rate is increased, causing the molten pool to suddenly rebound and deepen during subsequent melting rate increases, destroying the initial solidified shell formed earlier. If the holding time exceeds 50%, the molten pool will overcool, the fluidity of the molten metal at the top will decrease prematurely, and the compensating effect of subsequent melting rate increases will be significantly weakened.
[0050] Therefore, the time for maintaining the preset melting rate in this invention accounts for 30%, 32%, 33%, 35%, 37%, 39%, 40%, 41%, 43%, 45%, 48%, or 50% of the total duration of the heat sealing stage.
[0051] Specifically, the hot capping stage accounts for 10% to 25% of the total smelting time.
[0052] It should be noted that the hot capping stage should account for 10% to 25% of the total melting time. This ensures the effectiveness of top feeding and densification while balancing the efficiency, cost, and overall microstructure of the consumable ingot, avoiding defects and waste caused by excessively short or long capping times. If the hot capping time is less than 10%, the temperature field and morphology of the molten pool will not have enough time to stabilize, the feeding and filling during the rate-increasing stage will be insufficient, and the smooth solidification during the rate-decrease stage will not be completed, ultimately leaving defects such as central shrinkage cavities and porosity. If it is more than 25%, it will increase the energy consumption of the vacuum consumable furnace and also damage the fine-grained uniform microstructure of the consumable ingot.
[0053] Therefore, the time of the hot capping stage in this invention accounts for 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25% of the total melting time.
[0054] Specifically, the diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 920 mm, corresponding to a melting rate of 7–12 kg / min during the stable melting stage, and a heat-sealed weight of 960–1800 kg. The diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 810 mm, corresponding to a melting rate of 4–9 kg / min during the stable melting stage, and a heat-sealed weight of 800–1500 kg. The diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 660 mm, corresponding to a melting rate of 3–8 kg / min during the stable melting stage, and a heat-sealed weight of 480–900 kg.
[0055] It should be noted that coordinating the ingot shape with the melting rate and hot capping weight during the stable smelting stage can effectively match the molten pool characteristics and solidification shrinkage patterns of large-diameter ingots, balancing smelting stability, feeding effect, and industrial production efficiency. If the melting rate is too low, the molten pool will be too shallow, leading to cold shuts and slag inclusions on the ingot surface, while smelting efficiency will decrease significantly. If the melting rate is too high, the molten pool depth will increase dramatically, significantly slowing down the cooling rate in the central region of the large-diameter ingot, easily forming coarse columnar crystal structures and reducing the mechanical properties of the consumable ingot. If the hot capping weight is too low, the amount of feeding molten metal will be insufficient to completely fill the shrinkage gaps, ultimately leaving defects such as central shrinkage cavities and porosity. If the hot capping weight is too high, it will lead to deterioration of microstructure and properties, while increasing the energy consumption of the consumable furnace.
[0056] This invention provides a large-scale nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot, which is prepared by the hot-sealing process described in this invention.
[0057] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.
[0058] Example 1
[0059] Preparation of GH4145 nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot:
[0060] The GH4145 electrode ingot was subjected to vacuum consumable remelting, including an arc-starting stage and a stable melting stage. The melting rate during the stable melting stage was 6.5 kg / min. When the remaining weight of the electrode ingot was 10% of the total weight, it entered the hot capping stage, with a total hot capping time of 194 min. The process included the following steps:
[0061] S1: Reduce power to decrease the melting rate from the stable melting stage to the preset melting rate, and reduce it to 1.5 kg / min within 60 minutes;
[0062] S2: Maintain the preset melting rate of 1.5 kg / min for 80 minutes; then increase the power to no more than 0.1 kg / min. 2 The melting rate was increased to 3.5 kg / min in 30 minutes and maintained for 20 minutes;
[0063] S3: at 0.6kg / mm 2 The melting rate is reduced, and when the weight of the remaining electrode ingot is less than 3%, the power supply is stopped, the hot capping stage ends, and after solidification, a nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is obtained.
[0064] Example 2
[0065] The preparation process of Example 2 is largely the same as that of Example 1, except that in Example 2... Preparation of Inconel 617 nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot:
[0066] The melting rate during the stable smelting stage is 5 kg / min, and the total time for hot capping is 100 min.
[0067] S1: Reduce power to decrease the melting rate from the stable melting stage to the preset melting rate, and reduce it to 1.5 kg / min within 30 minutes;
[0068] S2: Maintain the preset melting rate of 1.5 kg / min for 40 minutes; then increase the power to no more than 0.1 kg / min. 2 The melting rate was increased to 2.2 kg / min in 10 minutes and maintained for 10 minutes;
[0069] S3: at 0.5kg / mm 2The melting rate is reduced, and when the weight of the remaining electrode ingot is less than 3%, the power supply is stopped, the hot capping stage ends, and after solidification, a nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is obtained.
[0070] Example 3
[0071] The preparation process of Example 3 is largely the same as that of Example 1, except that in Example 3, the preparation method is... Preparation of GH4169 nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot:
[0072] The melting rate during the stable smelting stage is 9 kg / min, and the total time for hot capping is 240 min.
[0073] S1: Reduce power to decrease the melting rate from the stable melting stage to the preset melting rate, which will decrease to 2.5 kg / min within 75 minutes;
[0074] S2: Maintain the preset melting rate of 2.5 kg / min for 100 min; then increase the power to no more than 0.1 kg / min. 2 The melting rate was increased to 4.0 kg / min in 30 minutes and maintained for 25 minutes;
[0075] S3: at 0.8kg / mm 2 The melting rate is reduced, and when the weight of the remaining electrode ingot is less than 3%, the power supply is stopped, the hot capping stage ends, and after solidification, a nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is obtained.
[0076] Comparative Example 1
[0077] The preparation process of Comparative Example 1 is largely the same as that of Example 1, except that in Comparative Example 1... Preparation of GH4145 nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot: The total hot sealing time is 155 min, and the melting rate is directly reduced until the hot sealing is completed.
[0078] Comparative Example 2
[0079] The preparation process of Comparative Example 2 is largely the same as that of Example 1, except that the total heat sealing time in Comparative Example 2 is 248 min.
[0080] First, rapidly reduce the melting rate to 2.5 kg / min over 70 minutes, then slowly reduce the melting rate to 1 kg / min over 70 minutes, and finally reduce the melting rate until the heat sealing is completed.
[0081] Comparative Example 3
[0082] The preparation process of Comparative Example 3 is largely the same as that of Example 1, except that the total heat sealing time in Comparative Example 3 is 102 min.
[0083] First, reduce the melting rate to 4.5 kg / min after 85 minutes, then rapidly reduce it to 2.5 kg / min after 15 minutes, and finally reduce the melting rate until the heat capping is completed.
[0084] Comparative Example 4
[0085] The preparation process of Comparative Example 4 is largely the same as that of Example 2, except that in Comparative Example 4... Preparation of Inconel 617 stainless steel vacuum consumable ingot: The total heat sealing time is 55 minutes, and the melting rate is directly reduced until the heat sealing is completed.
[0086] Comparative Example 5
[0087] The preparation process of Comparative Example 5 is largely the same as that of Example 2, except for the preparation of the φ660mm GH4169 nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot in Comparative Example 5:
[0088] The melting rate during the stable smelting stage is 4.5 kg / min, and the total time for hot capping is 50 min.
[0089] First, the melting rate is rapidly reduced to 2.0 kg / min over 22 minutes, then slowly reduced to 1 kg / min over 20 minutes, and finally reduced until the heat sealing is completed.
[0090] Comparative Example 6
[0091] The preparation process of Comparative Example 6 is largely the same as that of Example 3. The difference is that the total heat sealing time in Comparative Example 6 is 150 min, and the melting rate is directly reduced until the heat sealing is completed.
[0092] tissue testing
[0093] The tissue samples from the above embodiments and comparative examples were subjected to tissue testing, and the test results are shown in Table 1.
[0094] Table 1. Tissue Detection Results
[0095]
[0096] Combined with Examples 1-3 and Comparative Examples 1-6 and referring to Table 1 and Figure 1-5 It can be seen that the hot capping process of the large nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot provided by the present invention produces nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingots without defects such as black spots and shrinkage cavities, and the size of the primary precipitated phase is small, below 15μm.
[0097] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A process for hot end-capping of large size nickel-base heat and corrosion resistant alloy vacuum consumable ingot, characterized by, The electrode ingot undergoes vacuum consumable remelting, proceeding through an arc-starting stage and a stable melting stage. When the remaining weight of the electrode ingot is 8%-15% of the total weight, it enters the hot capping stage; this includes the following steps: S1: Reduce power to decrease the melting rate from the melting rate during the stable melting stage to the preset melting rate; S2: maintain the preset melt rate, then increase the power to increase the melt rate at a rate not higher than 0.1 kg / min 2 to the target melt rate; S3: the rate of the melting speed is reduced to not more than 0.8 kg / min 2 and when the weight of the remaining electrode ingot is less than 3%, the power supply is stopped, the hot-top stage is finished, and a nickel-based heat and corrosion resistant alloy vacuum consumable ingot is obtained after solidification.
2. The process as claimed in claim 1, wherein the process is a hot end plugged process for producing large size nickel base heat and corrosion resistant alloy vacuum arc remelted ingot. The diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is ≥660mm.
3. The process as claimed in claim 1, wherein the process is a hot end plugged process for producing large size nickel base heat and corrosion resistant alloy vacuum arc remelted ingot. In step S1, the preset melting rate is 1 / 5 to 1 / 3 of the melting rate during the stable melting stage.
4. The process as claimed in claim 1, wherein the process is a hot end plugged process for producing large size nickel base heat and corrosion resistant alloy vacuum arc remelted ingot. In step S2, the increased melting rate is no higher than 2 / 3 of the melting rate in the stable melting stage, and the duration of maintaining the increased melting rate accounts for 8% to 15% of the total heat capping time.
5. The process as claimed in claim 1, wherein the process is a hot end plugged process for producing large size nickel base heat and corrosion resistant alloy consumable vacuum arc remelted ingot. The time for maintaining the preset melting rate accounts for 30% to 50% of the total duration of the hot capping stage.
6. The process as claimed in claim 1, wherein the process is a hot end plugged process for producing large size nickel base heat and corrosion resistant alloy consumable vacuum arc remelted ingot. The hot capping stage accounts for 10% to 25% of the total melting time.
7. The process as claimed in claim 2, wherein the process is a hot end plugged process for producing large size nickel base heat and corrosion resistant alloy vacuum arc remelted ingot. The diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 920 mm, the melting rate of the stable melting stage is 7-12 kg / min, and the weight of the hot capping is 960-1800 kg.
8. The process as claimed in claim 2, wherein the process is a hot end plugged process for producing large size nickel base heat and corrosion resistant alloy vacuum arc remelted ingot. The diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 810 mm, the melting rate of the stable melting stage is 4-9 kg / min, and the weight of the hot capping is 800-1500 kg.
9. The hot sealing process for a large nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot according to claim 2, characterized in that, The diameter of the nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot is 660 mm, the melting rate of the stable melting stage is 3-8 kg / min, and the weight of the hot capping is 480-900 kg.
10. A large nickel-based heat-resistant and corrosion-resistant alloy vacuum consumable ingot, characterized in that, It is prepared by the heat sealing process according to any one of claims 1-9.