Low-segregation high-temperature alloy and control method for segregation defects of high-temperature alloy

Abstract

The invention relates to the technical field of high-temperature alloys, and provides a low-segregation high-temperature alloy and a control method for segregation defects of the high-temperature alloy, and the control method comprises the following steps: S1, according to the ingot type size of a high-temperature alloy vacuum consumable ingot, determining the height of the high-temperature alloy vacuum consumable ingot corresponding to the reduction of the melting speed in a vacuum consumable steady-state smelting period; according to the content range of segregation elements in the high-temperature alloy, the melting speed decreasing range is determined; according to the ingot shape size of the high-temperature alloy vacuum consumable ingot, the helium pressure drop range in the heat top sealing period is determined; and S2, carrying out vacuum consumable smelting on the high-temperature alloy according to the vacuum consumable smelting process determined in the step S1. According to the control method provided by the invention, the problem of black spot control of high-temperature alloy vacuum consumable ingots with different ingot types and alloy component marks is solved, and the low-segregation high-temperature alloy consumable ingots are prepared.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high-temperature alloy manufacturing, and particularly relates to a low-segregation high-temperature alloy and a method for controlling segregation defects of high-temperature alloy. BACKGROUND

[0002] High-temperature alloys have excellent creep resistance, high-temperature strength, corrosion resistance and fatigue performance, and can work stably for a long time in a high-temperature environment above 600℃, and are widely used in key fields such as aerospace, petroleum and chemical industry.

[0003] Vacuum consumable smelting is an important secondary smelting process for producing high-quality high-temperature alloys. A large number of studies have shown that due to the high alloying degree and complex composition of high-temperature alloys, black spot segregation defects are prone to occur during the consumable smelting process. This segregation defect significantly reduces the toughness, yield strength and endurance performance of high-temperature alloys, resulting in material waste, which has been listed as a high-risk quality problem in the industry and will directly lead to the scrap of high-temperature alloy products once found. Therefore, reducing or eliminating black spot segregation defects in the vacuum consumable smelting process plays an important role in the manufacturing and development of high-temperature alloys.

[0004] For black spot segregation defects, it is found that as the smelting process proceeds, the cooling effect of the crystallizer bottom plate weakens, the local solidification time of the alloy at the head of the ingot (the feeding end, A end) becomes longer, and the alloy solidification segregation tendency is serious, so that black spot problems are prone to occur in this part. Chinese patents with publication numbers CN115896471A and CN116287744A propose to increase gas cooling in the later stage of consumable smelting to reduce black spot segregation at the head of the ingot; however, the use of large flow gas cooling in the above-mentioned patents will reduce the vacuum degree during the smelting process, resulting in unstable arc and molten pool, which will increase the probability of black spot formation. In addition, Chinese patent with publication number CN117926020A proposes to start reducing the melting rate at a position 1 / 4~1 / 3 height from the top of the ingot in the later stage of stable smelting to reduce the heat input at the head of the ingot and reduce black spot segregation at the head of the ingot; however, the application and implementation of this technology are mainly for Φ508mm ingot type, and this technology does not consider the influence of alloy composition on smelting rate and black spot.

[0005] In summary, although researchers have carried out some research work on the improvement of black spot segregation problems of vacuum consumable ingots, there are still some deficiencies in the research work and the results obtained; the existing technology has not paid attention to the black spot control problem of high-temperature alloy consumable ingots of different ingot sizes and alloy composition grades. SUMMARY

[0006] The technical problem solved by the present application is to provide a control method for segregation defects of high-temperature alloy, which can control the segregation defects, especially black spot segregation, of consumable ingots of different ingot types and different alloy component grades of high-temperature alloy, and finally ensure to obtain low-segregation high-temperature alloy consumable ingot products.

[0007] Therefore, the present application provides a control method for segregation defects of high-temperature alloy, which comprises the following steps:

[0008] S1, determining the height of the high-temperature alloy vacuum consumable ingot corresponding to the melting rate reduction of the vacuum consumable steady-state smelting period according to the ingot size of the high-temperature alloy vacuum consumable ingot;

[0009] determining the range of the melting rate reduction according to the content range of the segregation element in the high-temperature alloy;

[0010] determining the helium pressure reduction range of the hot sealing top period according to the ingot size of the high-temperature alloy vacuum consumable ingot;

[0011] S2, vacuum consumable smelting the high-temperature alloy according to the vacuum consumable smelting process determined in step S1.

[0012] In some specific embodiments, in step S1, the ingot size of the high-temperature alloy vacuum consumable ingot comprises one or more of Φ406mm, Φ508mm and Φ660mm.

[0013] In some specific embodiments, in step S1, the segregation element comprises three or four of W, Mo, Al and Ti.

[0014] In some specific embodiments, when the ingot size of the high-temperature alloy vacuum consumable ingot is Φ406mm, the melting rate is reduced from the position 1 / 6-1 / 4 of the height of the high-temperature alloy vacuum consumable ingot during the vacuum consumable steady-state smelting process.

[0015] When the ingot size of the high-temperature alloy vacuum consumable ingot is Φ508mm, the melting rate is reduced from the position 1 / 4-1 / 3 of the height of the high-temperature alloy vacuum consumable ingot during the vacuum consumable steady-state smelting process.

[0016] When the ingot size of the high-temperature alloy vacuum consumable ingot is Φ660mm, the melting rate is reduced from the position 1 / 3-1 / 2 of the height of the high-temperature alloy vacuum consumable ingot during the vacuum consumable steady-state smelting process.

[0017] In some specific embodiments, when the ingot size of the high-temperature alloy vacuum consumable ingot is Φ406mm, the content range of the segregation element is lower than the threshold range, the melting rate reduction range is 0.10-0.15kg / min, and the content range of the segregation element is in the threshold range, the melting rate reduction range is 0.16-0.30kg / min.

[0018] In some embodiments, when the ingot size of the high-temperature alloy vacuum consumable ingot is Φ508 mm, the melting rate reduction range is 0.30-0.50 kg / min when the content range of the segregation element is below the threshold range, and the melting rate reduction range is 0.51-0.70 kg / min when the content range of the segregation element is in the threshold range.

[0019] In some embodiments, when the ingot size of the high-temperature alloy vacuum consumable ingot is Φ660 mm, the melting rate reduction range is 0.45-0.65 kg / min when the content range of the segregation element is below the threshold range, and the melting rate reduction range is 0.66-0.85 kg / min when the content range of the segregation element is in the threshold range.

[0020] In some embodiments, the threshold range is: Mo 7.0-10wt%, W 2-4.5wt%, Ti 3-3.5wt%, and Al 1.0-2.5wt%.

[0021] In some embodiments, when the ingot size of the high-temperature alloy vacuum consumable ingot is Φ406 mm, the helium pressure is reduced to 1 / 4-1 / 3 of the steady-state melting period in the hot sealing top period of vacuum consumable smelting.

[0022] When the ingot size of the high-temperature alloy vacuum consumable ingot is Φ508 mm, the helium pressure is reduced to 1 / 3-1 / 2 of the steady-state melting period in the hot sealing top period of vacuum consumable smelting.

[0023] When the ingot size of the high-temperature alloy vacuum consumable ingot is Φ660 mm, the helium pressure is reduced to 1 / 2-2 / 3 of the steady-state melting period in the hot sealing top period of vacuum consumable smelting.

[0024] The application also provides a low-segregation high-temperature alloy, which is obtained by vacuum consumable remelting smelting, and the vacuum consumable remelting smelting is performed according to the control method described in the above scheme.

[0025] The application provides a high-temperature alloy segregation defect control method, which firstly determines a specific position of a vacuum consumable ingot head according to an ingot size of the high-temperature alloy vacuum consumable ingot, and reduces a smelting melt rate in advance to avoid an increase in cost of a small ingot size consumable ingot smelting position and effectively control a black spot problem of a large ingot size consumable ingot smelting melt rate reduction position; meanwhile, the content range of a segregation element in the high-temperature alloy is combined, the segregation element content is higher, the segregation tendency is greater, and the black spot defect is more likely to occur, the appropriate melt rate reduction range is determined according to the content range of the segregation element to avoid the problems of a large melt rate reduction, a small smelting melt rate, a long period, a poor surface quality of the consumable ingot and a white spot prone to occur in the high-temperature alloy with less segregation element, and the problems of a small melt rate reduction, a large smelting melt rate and a black spot prone to occur in the alloy with more segregation element; further, the appropriate helium pressure reduction range of the hot sealing top period is determined according to the ingot size of the vacuum consumable smelting consumable ingot to enhance the helium cooling effect of the upper part of the consumable ingot and reduce the black spot formation tendency of the consumable ingot.

[0026] Therefore, the high-temperature alloy segregation defect control method provided by the application determines the appropriate steady-state smelting melt rate reduction position, melt rate reduction range and helium reduction range of the hot sealing top period by studying the internal relationship between the ingot size of the high-temperature alloy vacuum consumable ingot, alloy composition and black spot formation of the consumable ingot, thereby realizing effective control of the black spot of the high-temperature alloy vacuum consumable ingot with different ingot sizes and different component grades, and obtaining a low-segregation high-temperature alloy. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A macro photograph of a high-temperature alloy product prepared in Example 3 of the application;

[0028] Figure 2 A macro photograph of a high-temperature alloy product prepared in Comparative Example 7 of the application. DETAILED DESCRIPTION

[0029] In order to further understand the application, the preferred embodiments of the application are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the application, and are not a limitation on the claims of the application.

[0030] In view of the fact that the high-temperature alloy black spot formation in the prior art is not associated with the high-temperature alloy ingot size and alloy composition grade, and thus the control of the black spot of the consumable ingot of the high-temperature alloy with different ingot sizes and different grades cannot be achieved, the present application provides a control method for black spot segregation of high-temperature alloy vacuum consumable smelting, which solves the problem of black spot control of the high-temperature alloy consumable ingot with different ingot sizes and alloy composition grades, and prepares a low-segregation high-temperature alloy; in the actual production process, the black spot segregation tendency of the high-temperature alloy with different ingot sizes, different compositions, i.e., different grades, is different, and correspondingly, the smelting melt rate drop position and range are different, and the helium pressure size at the hot sealing top time is also different, so it is necessary to adapt the melt rate drop position, drop range of the steady-state smelting period and the helium pressure size at the hot sealing top period to reduce the generation of black spot defects and effectively shorten the smelting cycle. Specifically, the present application discloses a control method for segregation defects of high-temperature alloy, comprising the following steps:

[0031] S1, determining the height of the high-temperature alloy vacuum consumable ingot corresponding to the melt rate drop of the vacuum consumable steady-state smelting period according to the ingot size of the high-temperature alloy vacuum consumable ingot;

[0032] determining the range of the melt rate drop according to the content range of the segregation element in the high-temperature alloy;

[0033] determining the helium pressure drop range of the hot sealing top period according to the ingot size of the high-temperature alloy vacuum consumable ingot;

[0034] S2, vacuum consumable smelting the high-temperature alloy according to the vacuum consumable smelting process determined in step S1.

[0035] In the control method for segregation defects of high-temperature alloy provided in the present application, first, based on different high-temperature alloy vacuum consumable ingot sizes, the melt rate drop position of the high-temperature alloy in the vacuum consumable steady-state smelting period is determined, i.e., the consumable ingot height corresponding to the start of the melt rate drop; in the vacuum consumable smelting process, the larger the ingot size of the consumable ingot, the larger the smelting melt rate, the deeper the smelting bath, the more serious the longitudinal heat accumulation of the consumable ingot, and the more prone to segregation of the upper part of the consumable ingot. In order to avoid the segregation of the consumable ingot, it is found through research that as the size of the consumable ingot increases, the smelting speed needs to be reduced in advance at a position farther away from the head of the consumable ingot in the steady-state smelting period, so as to effectively reduce the longitudinal heat accumulation and black spot formation tendency of the large ingot consumable ingot.

[0036] In some specific embodiments, the ingot size of the high-temperature alloy vacuum consumable ingot includes at least one of Φ406mm, Φ508mm and Φ660mm; for those skilled in the art, the ingot size represents different diameter sizes of the consumable ingot.

[0037] On the basis of the above ingot size, according to different consumable ingot ingot type, the position of the high-temperature alloy vacuum consumable ingot at which the melting rate decreases in the later stage of vacuum consumable steady-state smelting, i.e. the corresponding consumable ingot height at which the melting rate begins to decrease, is determined, comprising:

[0038] When the consumable ingot ingot type is Φ406mm ingot type, the melting rate begins to decrease at a position 1 / 6~1 / 4 height away from the top of the consumable ingot in the later stage of steady-state smelting, specifically, the melting rate begins to decrease at a position 1 / 6, 1 / 5, 1 / 4 height away from the top of the consumable ingot in the later stage of steady-state smelting.

[0039] When the consumable ingot ingot type is Φ508mm ingot type, the melting rate begins to decrease at a position 1 / 3~1 / 4 height away from the top of the consumable ingot in the later stage of steady-state smelting.

[0040] When the consumable ingot ingot type is Φ660mm ingot type, the melting rate begins to decrease at a position 1 / 2~1 / 3 height away from the top of the consumable ingot in the later stage of steady-state smelting.

[0041] In the present application, according to the consumable ingot ingot size and black spot segregation characteristics, for large ingot type (such as Φ660mm ingot type), the consumable ingot has a large longitudinal segregation tendency, in order to effectively avoid black spot defects in the smelting process, the smelting melting rate begins to decrease at a position far away from the top of the consumable ingot (1 / 2~1 / 3 height position); for small ingot type consumable ingot (such as Φ406mm ingot type), the consumable ingot has a small longitudinal segregation tendency, while avoiding the generation of black spots, the smelting melting rate begins to decrease at a position close to the top of the consumable ingot (1 / 6~1 / 4 height position). For the same ingot type (in terms of diameter) of the high-temperature alloy vacuum consumable ingot, if the melting rate decrease position exceeds the above range height, the whole smelting period will be long, and the production cost will be increased; if the melting rate decrease position is lower than the above range height, the effect of reducing the heat accumulation phenomenon at the head of the consumable ingot will not be significant, and it is difficult to effectively reduce the black spot defects.

[0042] On the basis of the above, for the ingot size, based on the alloy composition, according to the content range of the segregation elements in the high-temperature alloy, the range of the above melting rate decrease is determined; as described above, the ingot size includes at least one of Φ406mm, Φ508mm, Φ660mm, and the segregation elements in the high-temperature alloy are selected from three or four of W, Mo, Al and Ti, i.e. the segregation elements in the high-temperature alloy contain three of W, Mo, Al and Ti, or all of W, Mo, Al and Ti.

[0043] In some specific embodiments, on the basis of the determination of the ingot size, based on the high-temperature alloy composition, the melting rate decrease range of the high-temperature alloy consumable ingot in the later stage of vacuum consumable steady-state smelting is determined, comprising:

[0044] When the self-consuming ingot ingot type is Φ406mm ingot type, the melting rate is reduced at the position of 1 / 6~1 / 4 height from the top of the self-consuming ingot in the later stage of the steady-state smelting, and when the content of the easily segregating element is lower than the specified range (threshold range), the melting rate reduction range is 0.10~0.15kg / min; when the content of the easily segregating element is in the specified range, the melting rate reduction range is 0.16~0.30kg / min.

[0045] When the self-consuming ingot ingot type is Φ508mm ingot type, the melting rate is reduced at the position of 1 / 3~1 / 4 height from the top of the self-consuming ingot in the later stage of the steady-state smelting, and when the content of the easily segregating element is lower than the specified range, the melting rate reduction range is 0.30~0.50kg / min; when the content of the easily segregating element is in the specified range, the melting rate reduction range is 0.51~0.7kg / min.

[0046] When the self-consuming ingot ingot type is Φ660mm ingot type, the melting rate is reduced at the position of 1 / 2~1 / 3 height from the top of the self-consuming ingot in the later stage of the steady-state smelting, and when the content of the easily segregating element is lower than the specified range, the melting rate reduction range is 0.45~0.65kg / min; when the content of the easily segregating element is in the specified range, the melting rate reduction range is 0.66~0.85kg / min.

[0047] The above specified range (threshold range) is: Mo 7.0~10wt%, W 2~4.5wt%, Ti 3~3.5wt%, Al 1.0~2.5wt%.

[0048] In some embodiments, for different ingot sizes, based on the content range of alloy components, especially the content of segregating elements, the melting rate reduction range of the high-temperature alloy self-consuming ingot in the later stage of the vacuum self-consuming steady-state smelting is determined, when the high-temperature alloy self-consuming ingot ingot type is Φ406mm ingot type, and the content of the easily segregating element is lower than the specified range (threshold range), the melting rate reduction range in the later stage of the steady-state smelting is 0.10~0.15kg / min, and when the content of the easily segregating element is lower than the specified range, the melting rate reduction range is 0.16~0.30kg / min.

[0049] When the high-temperature alloy self-consuming ingot ingot type is Φ508mm ingot type, and the content of the easily segregating element is lower than the specified range, the melting rate reduction range in the later stage of the steady-state smelting is 0.30~0.50kg / min, and when the content of the easily segregating element is in the specified range, the melting rate reduction range is 0.51~0.7kg / min.

[0050] When the self-consumption ingot ingot type is Φ660mm ingot type, and the content of the easily segregated element is lower than the specified range, the melting rate reduction range in the later stage of steady-state smelting is 0.45-0.65 kg / min, and when the content of the easily segregated element is in the specified range, the melting rate reduction range is 0.66-0.85 kg / min.

[0051] In the present application, for different ingot sizes, considering that the longitudinal segregation of the self-consumption ingot increases with the increase of the ingot size, it is found that with the increase of the ingot size, the melting rate reduction range increases, so as to effectively reduce the black spot segregation tendency of the self-consumption ingot. Meanwhile, for a certain ingot size, when the content of the easily segregated element is lower than the specified range, the alloy segregation tendency is small, and a smaller melting rate reduction range is adopted, so as to reduce the black spot of the self-consumption ingot while ensuring that the production cycle and cost are not significantly affected. When the content of the easily segregated element is in the specified range, the alloy segregation tendency is large, and a larger melting rate reduction range is adopted, so as to ensure that the longitudinal heat accumulation of the self-consumption ingot can be effectively reduced, and the black spot defect of the self-consumption ingot head can be reduced. If the melting rate reduction range exceeds the above range, the whole smelting cycle will be long, and the production cost will be increased. If the melting rate reduction range is lower than the above range, it is difficult to effectively reduce the black spot defect.

[0052] In the present application, when three of the above segregation elements are lower than the above specified range, the melting rate reduction value is according to the melting rate reduction range lower than the specified range, and when three of the above segregation elements are in the above specified range, the melting rate reduction value is according to the melting rate reduction range in the specified range. The range of the segregation element cannot contain both the range lower than the specified range and the range in the specified range. The above range lower than the specified range means that the maximum value in the range of the segregation element is less than the minimum value in the specified range, and the above range in the specified range means that both the maximum value and the minimum value in the range of the segregation element are in the specified range.

[0053] Finally, the helium pressure reduction range and the helium pressure value at the hot sealing top sealing period are determined based on different ingot sizes.

[0054] In some specific embodiments, the helium pressure reduction range and the helium pressure at the hot sealing top sealing period are determined according to different ingot sizes, specifically:

[0055] When the self-consumption ingot ingot type is Φ406mm ingot type, the helium pressure gradually decreases to 1 / 4-1 / 3 of the steady-state helium pressure size at the hot sealing top sealing period of the vacuum self-consumption smelting, and then remains stable;

[0056] When the self-consumption ingot ingot type is Φ508mm ingot type, the helium pressure gradually decreases to 1 / 3-1 / 2 of the steady-state helium pressure size at the hot sealing top sealing period of the vacuum self-consumption smelting, and then remains stable;

[0057] When the self-consuming ingot ingot type is Φ660mm ingot type, the helium pressure gradually decreases to 1 / 2~2 / 3 of the stable helium pressure size and then remains stable when entering the vacuum self-consuming smelting hot sealing top period.

[0058] It is found through research that, with the increase of the ingot size, the helium pressure value is appropriately increased and maintained at the hot sealing top period, so as to enhance the helium cooling effect of the upper part of the self-consuming ingot, reduce the tendency of black spot formation of the self-consuming ingot, avoid the phenomenon that the helium pressure is large during the hot sealing top smelting of the small ingot, the molten pool is easily broken, and the smelting process is unstable, and avoid the problem that the helium pressure is small during the hot sealing top smelting of the large ingot, and it is difficult to effectively reduce the black spot of the head of the self-consuming ingot.

[0059] In the above-mentioned vacuum self-consuming remelting process, the process parameters are determined according to the ingot size of the high-temperature alloy vacuum self-consuming ingot, the alloy element (type and content), and especially the element segregation content, the melting speed drop position of the steady-state smelting period, the melting speed drop range and the helium pressure drop range of the hot sealing top period in the vacuum self-consuming process of the high-temperature alloy are determined, and then the above-mentioned vacuum self-consuming smelting process is used for vacuum self-consuming smelting of the high-temperature alloy self-consuming electrode rod, that is, in the process of vacuum self-consuming smelting of the high-temperature alloy, by analyzing the ingot size, the segregation element type and the content range of the high-temperature alloy vacuum self-consuming ingot, the related process parameters of the melting speed of the steady-state smelting period and the helium pressure of the hot sealing top period are determined to ensure that the high-temperature alloy vacuum self-consuming ingot does not have the problem of black spot segregation.

[0060] In the present application, the vacuum self-consuming smelting includes an arc starting stage, a steady-state melting stage and a hot sealing top stage, wherein the steady-state melting stage and the hot sealing top stage have an important effect on the black spot of the self-consuming ingot and have a great influence, therefore, the present application mainly focuses on the process parameters of the steady-state melting and the hot sealing top stage, and the parameters of the arc starting stage are performed according to the method well known to those skilled in the art, and the present application does not make special limitations.

[0061] The control method for black spot segregation in the vacuum self-consuming smelting of the high-temperature alloy provided by the present application first determines the melting speed drop position of the steady-state smelting period according to the ingot size, so as to effectively reduce the longitudinal heat accumulation and the black spot formation tendency of the large ingot self-consuming ingot. On this basis, the melting speed drop range of the steady-state smelting period is determined according to the alloy composition and the segregation characteristics, so as to avoid the problem that the alloy with high content of the easily-segregated element forms a black spot defect during the smelting process, and to avoid the problem that the smelting melting speed of the alloy with low content of the easily-segregated element is too low, and the smelting period is too long; on the basis of the above, the helium pressure drop range of the hot sealing top period is determined according to different ingot sizes, so as to further avoid the phenomenon that the helium pressure is large during the hot sealing top of the small ingot self-consuming ingot, the molten pool is easily broken, and the smelting process is unstable, and to avoid the problem that the helium pressure is small during the hot sealing top of the large ingot self-consuming ingot, and it is difficult to effectively reduce the black spot of the head of the self-consuming ingot.

[0062] The application also provides a low segregation high-temperature alloy obtained by vacuum self-consumption remelting smelting according to the control method.

[0063] The application provides a control method for black spot segregation in vacuum self-consumption smelting of a high-temperature alloy. For different ingot types and alloy grades of the high-temperature alloy, the black spot problem is solved by the following method. First, according to the research that the larger the size of the self-consumption ingot, the greater the smelting speed, the deeper the smelting pool, the more serious the longitudinal heat accumulation of the self-consumption ingot, and the greater the segregation of the upper part of the self-consumption ingot, it is obtained that, as the size of the self-consumption ingot increases, the smelting speed needs to be reduced at a position farther from the head of the self-consumption ingot in the steady-state smelting stage. This avoids the problem that, when a small ingot type self-consumption ingot is smelted, the smelting speed reduction position is too early, which increases the smelting cycle and cost. Meanwhile, this also avoids the problem that, when a large ingot type self-consumption ingot is smelted, the smelting speed reduction position is too late, which makes it difficult to effectively control the black spot.

[0064] Further, considering the segregation of alloy components, such as the higher the content of Al, Ti, W, Mo, etc. of the self-consumption ingot, the greater the segregation tendency, and the easier the black spot defect, it is proposed that the greater the segregation tendency of the alloy components, the higher the content, and the greater the smelting speed reduction range, so as to enhance the alloy cooling and solidification rate, effectively reduce the black spot formation tendency of the alloy with a high content of easily segregated elements under the same ingot size, and avoid the problems that, when the alloy with a small content of easily segregated elements is smelted, the smelting speed is greatly reduced, the smelting speed is small, the cycle is long, and the surface quality of the self-consumption ingot is poor, and the white spot is prone to occur. Meanwhile, this also avoids the problem that, when the alloy with a large content of easily segregated elements is smelted, the smelting speed is slightly reduced, the smelting speed is large, and the black spot is prone to occur.

[0065] Finally, on the basis of the above, based on the research that the larger the size of the self-consumption ingot, the greater the smelting speed, and the larger the volume and depth of the smelting pool, it is proposed that, as the size of the ingot increases, the decrease value of the helium pressure during the heat sealing top is smaller, that is, the helium pressure value during the heat sealing top is appropriately increased and maintained, so as to enhance the helium cooling effect of the upper part of the self-consumption ingot, reduce the black spot formation tendency of the self-consumption ingot, and avoid the problems that, when a small ingot type self-consumption ingot is heat sealed, the helium pressure is large, the smelting pool is prone to be disturbed, and the smelting process is unstable. Meanwhile, this also avoids the problem that, when a large ingot type self-consumption ingot is heat sealed, the helium pressure is small, and it is difficult to effectively reduce the black spot of the head of the self-consumption ingot. Therefore, the high-temperature alloy with different ingot types and different alloy components is matched with an appropriate vacuum self-consumption smelting process, and the generation of black spot segregation is effectively controlled.

[0066] In order to further understand the application, the control method for black spot segregation in vacuum self-consumption smelting of a high-temperature alloy provided by the application is described in detail below in combination with embodiments, and the protection scope of the application is not limited by the following embodiments.

[0067] Example 1

[0068] 1) The high-temperature alloy chemical composition is specifically as follows in mass percentage: C≤0.08%, Cr: 17~21%, Co≤1%, Mo: 2.8~3.3%, Al: 0.2~0.8%, Ti: 0.65~1.15%, Nb: 4.75~5.5%, the balance being Ni and some inevitable impurity elements; the consumable smelting electrode rod is prepared through the processes of vacuum induction smelting and pouring, annealing, sawing, peeling, baking and welding in sequence;

[0069] 2) The electrode rod prepared in step 1) is placed into a Φ406mm ingot-type consumable furnace as a consumable electrode, the furnace door is closed, vacuumizing is started, and when the vacuum degree and the leakage rate reach the requirements, i.e. the vacuum degree is less than 0.1Pa and the leakage rate is less than 0.1Pa / min, power supply is started to begin smelting;

[0070] In the 0~20min time, it is the arc starting stage of the consumable smelting of the high-temperature alloy, the arc starting stage adopts current+ voltage control, the current range of the arc starting stage is 3.0kA~7.0kA, the voltage range is 21V~25V, and the helium pressure of the arc starting stage is 0Pa;

[0071] 3) In the 21~450min time, it is the steady-state smelting stage of the consumable smelting of the high-temperature alloy, the steady-state smelting stage adopts droplet+melting rate control, the droplet number is 7 1 / s, the melting rate is 3.35kg / min, the helium is filled when the smelting time reaches 100min, the helium pressure is increased to 600Pa after the smelting time reaches 130min and then tends to be stable, and the smelting melting rate is reduced to reduce the heat input at the head position of the consumable ingot, i.e. the melting rate is gradually reduced from 3.35kg / min in the steady-state smelting stage to 3.2kg / min in the hot sealing top stage;

[0072] 4) In the 451~511min time, it is the hot sealing top stage of the consumable smelting of the high-temperature alloy, the hot sealing top stage adopts droplet+melting rate control, the droplet number is 11~16 1 / s, and the melting rate is 1.4~3.2kg / min; wherein, in the 451~470min time, it is the early stage of the hot sealing top smelting, the melting rate is gradually reduced from 3.2kg / min to 1.7kg / min during this period, the helium pressure is reduced from 600Pa in the steady state to 150Pa, i.e. the helium pressure is reduced to 1 / 4 of the steady state, and in the 471~511min time, it is the late stage of the hot sealing top smelting, the melting rate is gradually reduced from 1.7kg / min to 1.4kg / min during this period, and the helium pressure used is 150Pa;

[0073] 5) After the hot sealing top is completed, the consumable ingot is cooled in the crystallizer for 60min and then is taken out, and the high-temperature alloy consumable ingot is obtained after air cooling.

[0074] The smelted consumable ingot obtained by the above method does not have black spot defects.

[0075] Example 2

[0076] The preparation method of the superalloy is basically the same as that in Example 1, except that:

[0077] 1) In this example, Φ508mm vacuum consumable ingot type smelting is adopted, and a Φ508mm electrode rod for consumable ingot type is prepared through the processes of vacuum induction smelting and pouring-annealing-sawing-skinning-baking-welding in sequence;

[0078] 2) The electrode rod in step 1) is placed into a Φ508mm ingot type consumable furnace as a consumable electrode to prepare a superalloy by vacuum consumable remelting, and the arc striking stage for the consumable smelting is within 0~30min, the arc striking stage adopts current+ voltage control, the current range of the arc striking stage is 4.0kA~8.0kA, the voltage range is 21V~25V, and the helium pressure in the arc striking stage is 0Pa;

[0079] 3) The steady smelting stage for the consumable smelting is within 31~600min, the steady state adopts a droplet number of 6.5 1 / s and a melting speed of 4.3kg / min, and the melting speed is gradually reduced from 4.3kg / min in the steady smelting stage to 3.9kg / min in the hot sealing top stage to reduce the heat input at the head position of the consumable ingot, i.e. the melting speed is gradually reduced from 4.3kg / min in the steady smelting stage to 3.9kg / min in the hot sealing top stage;

[0080] 4) The hot sealing top stage for the consumable smelting is within 601~670min, the droplet number is 11~16 1 / s, and the melting speed is 1.8~3.9kg / min;

[0081] Among them, the hot sealing smelting early stage is within 601~620min, during which the melting speed is gradually reduced from 3.9kg / min to 2.1kg / min, and the helium pressure used is reduced from 600Pa in the steady state to 300Pa, i.e. the helium pressure is reduced to 1 / 2 of the steady state;

[0082] The hot sealing smelting late stage is within 621~670min, during which the melting speed is gradually reduced from 2.1kg / min to 1.8kg / min, and the helium pressure used is 300Pa;

[0083] 5) After the hot sealing top is completed, the consumable ingot is cooled in the crystallizer for 90min and then taken out, and the superalloy consumable ingot is obtained after air cooling.

[0084] The smelted consumable ingot obtained by the above method does not have black spot defects.

[0085] Example 3

[0086] The preparation method of the high-temperature alloy is basically the same as that in embodiment 1, except that:

[0087] 1) In this embodiment, a Φ660 mm vacuum consumable ingot type smelting is adopted, and a Φ660 mm electrode rod for the consumable ingot type is prepared through the processes of vacuum induction smelting and pouring-annealing-sawing-scaling-baking-welding in sequence.

[0088] 2) The electrode rod in step 1) is placed into a Φ660 mm ingot type consumable furnace as a consumable electrode, and the arc striking stage of the consumable smelting is within 0-65 min. The arc striking stage adopts current + voltage control, the current range of the arc striking stage is 5.0 kA-9.5 kA, the voltage range is 21 V-25 V, and the helium pressure of the arc striking stage is 0 Pa.

[0089] 3) The steady-state smelting stage of the consumable smelting is within 66-1400 min. The steady-state adopts a droplet number of 7 1 / s and a melting speed of 4.7 kg / min. The melting speed is gradually reduced from 4.7 kg / min in the steady-state smelting stage to 4.1 kg / min in the hot sealing top stage, so as to reduce the heat input at the head position of the consumable ingot, i.e., the melting speed is gradually reduced from 4.7 kg / min in the steady-state smelting stage to 4.1 kg / min in the hot sealing top stage.

[0090] 4) The hot sealing top stage of the consumable smelting is within 1401-1500 min, the droplet number is 11-16 1 / s, and the melting speed is 1.8-4.1 kg / min.

[0091] Among them, the hot sealing top smelting early stage is within 1501-1535 min, during which the melting speed is gradually reduced from 4.1 kg / min to 2.1 kg / min, and the helium pressure used is reduced from 600 Pa in the steady state to 400 Pa, i.e., the helium pressure is reduced to 2 / 3 of the steady state. The hot sealing top smelting later stage is within 1536-1600 min, i.e., the low melting speed holding smelting stage smelting time is 65 min, during which the melting speed is gradually reduced from 2.1 kg / min to 1.8 kg / min, and the helium pressure used is 400 Pa.

[0092] 5) After the hot sealing top is completed, the consumable ingot is cooled in the crystallizer for 120 min and then taken out. The high-temperature alloy consumable ingot is obtained after air cooling.

[0093] The smelted consumable ingot obtained according to the above method does not appear black spot defects, as shown in Figure 1 .

[0094] Embodiment 4

[0095] The preparation method of the high-temperature alloy is basically the same as that in embodiment 1, except that:

[0096] 1) The chemical composition of the nickel-based superalloy used in this embodiment is: C: 0.06~0.12%, Cr: 18~20%, Co: 10~12%, Mo: 9~10.5%, Al: 1.4~1.8%, Ti: 3~3.5%, the balance being Ni and some unavoidable impurity elements;

[0097] The melting rate at a position 1 / 5 height from the top of the consumable ingot gradually decreases from 3.3 kg / min in the steady melting stage to 3.0 kg / min in the hot sealing top stage;

[0098] The melting rate gradually decreases from 3.2 kg / min in the steady melting stage to 1.7 kg / min in the subsequent hot sealing top stage.

[0099] The smelted consumable ingot obtained by the above method does not have black spot defects.

[0100] Example 5

[0101] The preparation method of the superalloy is basically the same as that of Example 1, except that:

[0102] The melting rate at a position 1 / 4 height from the top of the consumable ingot gradually decreases from 3.35 kg / min in the steady melting stage to 3.2 kg / min in the hot sealing top stage;

[0103] The melting rate gradually decreases from 3.2 kg / min in the steady melting stage to 1.7 kg / min in the subsequent hot sealing top stage.

[0104] The smelted consumable ingot obtained by the above method does not have black spot defects.

[0105] Example 6

[0106] The preparation method of the superalloy is basically the same as that of Example 1, except that:

[0107] The melting rate at a position 1 / 6 height from the top of the consumable ingot gradually decreases from 3.35 kg / min in the steady melting stage to 3.2 kg / min in the hot sealing top stage;

[0108] The melting rate gradually decreases from 3.2 kg / min in the steady melting stage to 1.7 kg / min in the subsequent hot sealing top stage.

[0109] The smelted consumable ingot obtained by the above method does not have black spot defects.

[0110] Example 7

[0111] The preparation method of the superalloy is basically the same as that of Example 1, except that:

[0112] In the early stage of hot sealing top smelting, the helium pressure used is reduced from the steady state of 600 Pa to 200 Pa, that is, the helium pressure is reduced to 1 / 3 of the steady state, and the helium pressure in the later stage of hot sealing top smelting is kept at 200 Pa.

[0113] The smelted consumable ingot obtained by the above method does not have black spot defects.

[0114] Comparative Example 1

[0115] The preparation method of the high-temperature alloy is basically the same as that of Example 1, except that:

[0116] The melting rate at a position 1 / 7 of the height of the consumable ingot from the top is gradually reduced from 3.35 kg / min in the steady state smelting stage to 3.2 kg / min in the hot sealing top stage.

[0117] The smelted consumable ingot obtained by the above method has a significantly increased smelting time, which increases the production cycle and cost.

[0118] Comparative Example 2

[0119] The preparation method of the high-temperature alloy is basically the same as that of Example 1, except that:

[0120] The melting rate at a position 1 / 7 of the height of the consumable ingot from the top is gradually reduced from 3.35 kg / min in the steady state smelting stage to 3.2 kg / min in the hot sealing top stage.

[0121] The smelted consumable ingot obtained by the above method has a significantly increased smelting time, which increases the production cycle and cost.

[0122] Comparative Example 3

[0123] The preparation method of the high-temperature alloy is basically the same as that of Example 1, except that:

[0124] The melting rate at a position 1 / 5 of the height of the consumable ingot from the top is gradually reduced from 3.35 kg / min in the steady state smelting stage to 2.9 kg / min in the hot sealing top stage, and the smelting melting rate in the subsequent hot sealing top is gradually reduced from 2.9 kg / min to 1.7 kg / min.

[0125] In this comparative example, the steady state smelting melting rate is significantly reduced, which increases the smelting cycle and deteriorates the surface quality of the consumable ingot head.

[0126] Comparative Example 4

[0127] The preparation method of the high-temperature alloy is basically the same as that of Example 1, except that:

[0128] The melting rate is gradually reduced from 3.35 kg / min in the steady melting stage to 3.3 kg / min in the hot sealing top stage at a position 1 / 5 of the height of the top of the consumable ingot. The melting rate is gradually reduced from 3.3 kg / min to 1.7 kg / min in the subsequent hot sealing top stage.

[0129] In the present comparative example, the heat accumulation phenomenon of the head of the consumable ingot is serious, and the black spot formation tendency is large.

[0130] Comparative Example 5

[0131] The preparation method of the superalloy is basically the same as that of Example 1, except that:

[0132] In the early stage of the hot sealing top smelting at 451-470 min, the helium pressure is reduced from 600 Pa in the steady state to 100 Pa, that is, the helium pressure is reduced to 1 / 6 of the steady state. The helium pressure is maintained at 100 Pa in the later stage of the hot sealing top smelting.

[0133] In the present comparative example, the heat accumulation phenomenon of the head of the consumable ingot is serious, and the black spot formation tendency is large.

[0134] Comparative Example 6

[0135] The preparation method of the superalloy is basically the same as that of Example 1, except that:

[0136] In the early stage of the hot sealing top smelting at 451-470 min, the helium pressure is reduced from 600 Pa in the steady state to 300 Pa, that is, the helium pressure is reduced to 1 / 2 of the steady state. The helium pressure is maintained at 300 Pa in the later stage of the hot sealing top smelting.

[0137] In the present comparative example, the larger helium pressure is easy to break the molten pool, increase the instability of the smelting process, and lead to the white spot problem of the smelting consumable ingot.

[0138] Comparative Example 7

[0139] The preparation method of the superalloy is basically the same as that of Example 3, except that:

[0140] The constant smelting rate of 4.7 kg / min is used throughout the steady melting, and the smelting rate is gradually reduced from 4.7 kg / min to 2.4 kg / min in the hot sealing top stage of the consumable smelting.

[0141] In the present comparative example, the heat accumulation phenomenon of the consumable ingot in the smelting process is significant, and the black spot is serious, as shown in Figure 2 .

[0142] The above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be noted that for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

[0143] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling segregation defects in high-temperature alloys, comprising the following steps: S1. Determine the height of the high-temperature alloy vacuum consumable ingot corresponding to the decrease in melting rate during the vacuum consumable steady-state smelting period based on the ingot shape dimensions. The range of the decrease in melting rate is determined based on the content range of segregating elements in the high-temperature alloy; Based on the ingot dimensions of the high-temperature alloy vacuum consumable ingot, determine the range of helium pressure drop during the hot capping period; S2. Perform vacuum self-consumption smelting on the high-temperature alloy according to the vacuum self-consumption smelting process determined in step S1.

2. The control method according to claim 1, characterized in that, In step S1, the ingot size of the high-temperature alloy vacuum consumable ingot includes one or more of Φ406mm, Φ508mm, and Φ660mm.

3. The control method according to claim 1, characterized in that, In step S1, the segregation elements include three or four of W, Mo, Al and Ti.

4. The control method according to claim 2, characterized in that, When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ406mm, the melting rate begins to decrease at a height of 1 / 6 to 1 / 4 of the top of the high-temperature alloy vacuum consumable ingot during the vacuum consumable steady-state smelting process. When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ508mm, the melting rate begins to decrease at a height of 1 / 4 to 1 / 3 of the top of the high-temperature alloy vacuum consumable ingot during the vacuum consumable steady-state smelting process. When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ660mm, the melting rate begins to decrease at a height of 1 / 3 to 1 / 2 of the top of the high-temperature alloy vacuum consumable ingot during the vacuum consumable steady-state smelting process.

5. The control method according to claim 4, characterized in that, When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ406mm, the melting rate decreases by 0.10~0.15kg / min when the content of the segregated element is below the threshold range, and by 0.16~0.30kg / min when the content of the segregated element is within the threshold range.

6. The control method according to claim 4, characterized in that, When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ508mm, the melting rate decreases by 0.30~0.50kg / min when the content of the segregated element is below the threshold range, and by 0.51~0.70kg / min when the content of the segregated element is within the threshold range.

7. The control method according to claim 4, characterized in that, When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ660mm, the melting rate decreases by 0.45~0.65kg / min when the content of the segregated element is below the threshold range, and by 0.66~0.85kg / min when the content of the segregated element is within the threshold range.

8. The control method according to any one of claims 5 to 7, characterized in that, The threshold range is: Mo 7.0~10wt%, W 2~4.5wt%, Ti 3~3.5wt%, Al 1.0~2.5wt%.

9. The control method according to claim 8, characterized in that, When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ406mm, during the hot capping period of vacuum consumable smelting, the helium pressure drops to 1 / 4 to 1 / 3 of that during the steady-state smelting period. When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ508mm, during the hot capping period of vacuum consumable smelting, the helium pressure drops to 1 / 3 to 1 / 2 of that during the steady-state smelting period. When the high-temperature alloy vacuum consumable ingot has an ingot shape of Φ660mm, during the hot capping period of vacuum consumable smelting, the helium pressure drops to 1 / 2 to 2 / 3 of that during the steady-state smelting period.

10. A low-segregation high-temperature alloy, characterized in that, The high-temperature alloy is obtained by vacuum arc remelting, and the vacuum arc remelting is carried out according to the control method described in any one of claims 1 to 9.

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