A method for homogenizing and blooming of iron-nickel based superalloy ingot

Abstract

The application discloses a kind of iron-nickel-based superalloy homogenization billet methods, belong to superalloy technical field, for solving the problem that the existing large size iron-nickel-based superalloy ingot is often coarse after being homogenized, or the problem of uneven organization.The method comprises: first homogenization treatment, first short-time high-temperature homogenization, pre-upsetting, second short-time high-temperature homogenization and two-up two-draw;Among them, the temperature of the first short-time high-temperature homogenization is higher than that of the first homogenization treatment, and the two-up two-draw adopts narrow temperature zone forging + successive cooling mode.The method realizes the uniform fine-grained rod organization by adopting narrow temperature zone, two-up two-draw forging of successive cooling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature alloys, in particular to a uniformizing cogging method for iron-nickel-based high-temperature alloy ingots. BACKGROUND

[0002] Nickel-based alloys are important materials in the aerospace and energy power industries, and their market demand is growing. Nickel-based alloys such as GH4169 and GH4706 have good high-temperature creep strength, fatigue resistance, oxidation resistance and hot corrosion resistance, and relatively low cost, so they have become the most widely used high-temperature alloy in large-scale gas turbine discs.

[0003] With increasingly harsh service conditions, and in order to reduce production costs, the size of the ingot of the high-temperature alloy is continuously expanded, which makes the segregation in the ingot more serious and the organization more non-uniform, further reducing the hot working plasticity of the alloy. Therefore, the first step of deforming the high-temperature alloy, i.e., cogging, has become one of the production bottlenecks that limit the product yield. In the existing process, after the cogging of the large-size iron-nickel-based high-temperature alloy ingot, there are often problems of coarse organization or non-uniform organization, and cracks are prone to occur. SUMMARY

[0004] In view of the above, the present application aims to provide a uniformizing cogging method for iron-nickel-based high-temperature alloy ingots, which solves one of the problems that after the cogging of large-size iron-nickel-based high-temperature alloy ingots in the existing process, coarse organization or non-uniform organization often exists, and cracks are prone to occur.

[0005] The purpose of the present application is mainly achieved by the following technical solutions:

[0006] The present application provides a uniformizing cogging method for iron-nickel-based high-temperature alloy ingots, comprising: primary homogenization treatment, first short-time high-temperature homogenization, pre-upsetting, second short-time high-temperature homogenization and two-upsetting and two-drawing; wherein the temperature of the first short-time high-temperature homogenization is higher than the temperature of the primary homogenization treatment, and the two-upsetting and two-drawing adopts the mode of narrow temperature zone forging + gradual temperature reduction.

[0007] Further, the uniformizing cogging method for iron-nickel-based high-temperature alloy ingots comprises the following steps:

[0008] S1, the iron-nickel-based high-temperature alloy ingot is subjected to primary homogenization treatment at T0, and then the temperature is raised to T0+ΔT1 for the first short-time high-temperature homogenization treatment; wherein ΔT1=20-40℃;

[0009] S2, the furnace temperature is lowered to T0-ΔT1 for more than 2h of heat preservation for the iron-nickel-based high-temperature alloy ingot, and then the ingot is taken out of the furnace for pre-upsetting;

[0010] S3, the ingot after pre-upset is reheated and kept for a second short-time high-temperature homogenization treatment, the keeping temperature is controlled at T0+ΔT2; then the temperature is decreased to T0-ΔT1 and kept for at least 2 hours before the ingot is taken out, the ingot is subjected to a first upsetting; ΔT2=0-40℃;

[0011] S4, the ingot after the first upsetting is reheated and kept, the keeping temperature is controlled at T0-ΔT3, and kept for at least 2 hours before the ingot is taken out and subjected to a first drawing; ΔT3=40-60℃;

[0012] S5, the ingot after the first drawing is reheated and kept, the keeping temperature is controlled at T0-ΔT4, and kept for at least 2 hours before the ingot is taken out and subjected to a second upsetting; ΔT4=60-80℃;

[0013] S6, the ingot after the second upsetting is reheated and kept, the keeping temperature is controlled at T0-ΔT5, and kept for at least 2 hours before the ingot is taken out and subjected to a second drawing to obtain b; ΔT5=80-110℃.

[0014] Further, in S2, the deformation amount of the pre-upsetting is 10%-30%.

[0015] Further, in S2, the deformation rate of the pre-upsetting is 0.001-0.01s -1 .

[0016] Further, in S3, the deformation amount of the first upsetting is greater than that of the pre-upsetting.

[0017] Further, in S3, the deformation amount of the first upsetting is 30%-40%.

[0018] Further, in S3, the deformation rate of the first upsetting is controlled at 0.001-0.01s -1 .

[0019] Further, the keeping time of the primary homogenization treatment is t0, the keeping time of the first short-time high-temperature homogenization treatment is t1, and the keeping time of the second short-time high-temperature homogenization treatment is t2, the above keeping times and the diameter of the ingot satisfy the following relationships:

[0020] When the diameter of the ingot is 300-400mm, t0 is 14-17h, t1 is 14-17h, and t2 is 17-20h;

[0021] When the diameter of the ingot is 400-500mm, t0 is 17-20h, t1 is 17-20h, and t2 is 20-23h;

[0022] When the diameter of the ingot is 500-600mm, t0 is 20-24h, t1 is 20-24h, and t2 is 23-27h;

[0023] The ingot diameter is 600-700mm, t0 is 24-28h, t1 is 24-28h, and t2 is 27-31h;

[0024] The ingot diameter is 700-800mm, t0 is 28-34h, t1 is 28-34h, and t2 is 31-37h;

[0025] The ingot diameter is 800-900mm, t0 is 34-40h, t1 is 34-40h, and t2 is 37-43h;

[0026] The ingot diameter is 900mm, t0 is 40h, t1 is 40h, and t2 is 43h.

[0027] Further, in S4, the deformation amount of the first elongation is 20%-40%.

[0028] Further, in S5, the deformation amount of the second upsetting is 30%-40%.

[0029] Further, in S6, the deformation amount of the second elongation is 30%-40%.

[0030] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0031] The iron-nickel-based high-temperature alloy ingot homogenization and breaking-in method of the present application first eliminates low-melting-point phases in the alloy by adopting a first-stage homogenization treatment, then carries out a first short-time high-temperature homogenization treatment to eliminate part of the segregation but still leave some dendrites, which become recrystallization nucleation points in the pre-upsetting process and are conducive to recrystallization; the diffusion distance of the segregation elements is significantly shortened after pre-upsetting, and then a second short-time high-temperature homogenization treatment is carried out after pre-upsetting, which improves the segregation elimination efficiency and enables the dispersed recrystallized structure to fully undergo static recrystallization, further breaking the columnar crystal organization inheritance; the two-upsetting and two-elongation process in a narrow temperature range ensures that each or after completion, a finer grain structure is obtained than the previous one. The last elongation is ensured to have a uniform fine-grained structure by means of large deformation + low-temperature deformation. The method of the present application combines homogenization annealing and upsetting process by precisely controlling the sequence of each process and the process parameters of each step, thereby improving the efficiency and quality of large-size iron-nickel-based high-temperature alloy ingot homogenization and breaking-in. The two-upsetting and two-elongation forging process in a narrow temperature range and with successive temperature reduction realizes the obtaining of a uniform fine-grained rod structure.

[0032] The grain structure obtained by the method of the present application is fine and uniform, for example, the grain size is finer than 5 levels, and the maximum grain size level difference is not more than 3 levels, for example, the maximum grain size level difference of an iron-nickel-based high-temperature alloy ingot with a diameter of less than 550mm after being treated by the method is not more than 2 levels.

[0033] The method of the present application is not prone to cracks, has high yield, and is safe in process.

[0034] Other features and advantages of the present application will be set forth in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0036] Figure 1 is the recrystallization structure of the GH4169 alloy ingot after pre-upsetting + holding in Example 1;

[0037] Figure 2 is the recrystallization structure of the GH4169 alloy ingot after the first lengthening in Example 1;

[0038] Figure 3 is the recrystallization structure of the GH4169 alloy ingot after the second lengthening in Example 1;

[0039] Figure 4 is the recrystallization structure of the GH4706 alloy ingot after pre-upsetting + holding in Example 2;

[0040] Figure 5 is the recrystallization structure of the GH4706 alloy ingot after the first lengthening in Example 2;

[0041] Figure 6 is the recrystallization structure of the GH4706 alloy ingot after the second lengthening in Example 2;

[0042] Figure 7 is the recrystallization structure of the GH4169 alloy ingot after pre-upsetting + holding in Example 3;

[0043] Figure 8 is the recrystallization structure of the GH4169 alloy ingot after the second lengthening in Example 3;

[0044] Figure 9 is the recrystallization structure of the GH4169 alloy ingot after pre-upsetting + holding in Example 4;

[0045] Figure 10 is the recrystallization structure of the GH4169 alloy ingot after the second lengthening in Example 4;

[0046] Figure 11is the recrystallization structure of the GH4706 alloy ingot after pre-upsetting + holding in Example 5;

[0047] Figure 12 is the recrystallization structure of the GH4706 alloy ingot after the second lengthening in Example 5;

[0048] Figure 13 is the recrystallization structure of the GH4169 alloy ingot after the second lengthening in Comparative Example 1;

[0049] Figure 14 is the recrystallization structure of the GH4169 alloy ingot after the second lengthening in Comparative Example 2;

[0050] Figure 15 is the recrystallization structure of the GH4706 alloy ingot after the second lengthening in Comparative Example 3. DETAILED DESCRIPTION

[0051] The preferred embodiments of the present application will be described in detail below with reference to the drawings, wherein the drawings constitute a part of the present application and serve to explain the principles of the embodiments of the present application.

[0052] The inventors found in the research process that large-size (for example, a diameter of 300 mm or more) GH4169, GH4706 and other nickel-based alloy ingots often have coarse structure after breakdown, or uneven structure, and are prone to cracks. Therefore, the inventors provide a homogenization breakdown method for iron-nickel-based high-temperature alloy ingots, which can refine the structure of large-size iron-nickel-based high-temperature alloy ingots, improve the uniformity, improve the hot working performance, and reduce the crack sensitivity, thereby providing a rod blank with up-to-standard structure and performance for subsequent closed die forging.

[0053] The present application provides a homogenization breakdown method for iron-nickel-based high-temperature alloy ingots, comprising: primary homogenization treatment, first short-time high-temperature homogenization, pre-upsetting, second short-time high-temperature homogenization and two-up two-down; wherein the temperature of the first short-time high-temperature homogenization is higher than the temperature of the primary homogenization treatment, and the two-up two-down adopts the mode of narrow temperature zone forging + gradual cooling.

[0054] Specifically, the homogenization breakdown method for iron-nickel-based high-temperature alloy ingots of the present application is particularly suitable for nickel-based high-temperature alloy ingots with a diameter of 300 mm or more.

[0055] Specifically, the homogenization breakdown method for iron-nickel-based high-temperature alloy ingots comprises the following steps:

[0056] S1, homogenizing the iron-nickel-based high-temperature alloy ingot at T0 for primary homogenization treatment, and then increasing the temperature to T0+ΔT1 for holding for first short-time high-temperature homogenization treatment; wherein ΔT1=20-40℃;

[0057] S2, the furnace temperature is reduced to T0-ΔT1, and the iron-nickel-based superalloy ingot is preserved for more than 2 hours, and then the furnace is discharged to pre-upset the ingot;

[0058] S3, the pre-upset ingot is reheated and preserved, and a second short-time high-temperature homogenization treatment is performed, the preservation temperature is controlled at T0+ΔT2; then the temperature is reduced to T0-ΔT1 and preserved for at least 2 hours before the furnace is discharged, and the ingot is first upset; ΔT2=0-40℃;

[0059] S4, the first upset ingot is reheated and preserved, the preservation temperature is controlled at T0-ΔT3, and the preservation is at least 2 hours or more, and then the furnace is discharged for the first drawing; ΔT3=40-60℃;

[0060] S5, the first drawn ingot is reheated and preserved, the preservation temperature is controlled at T0-ΔT4, and the preservation is at least 2 hours or more, and then the furnace is discharged for the second upsetting; ΔT4=60-80℃;

[0061] S6, the second upset ingot is reheated and preserved, the preservation temperature is controlled at T0-ΔT5, and the preservation is at least 2 hours or more, and then the furnace is discharged for the second drawing to obtain b; ΔT5=80-110℃.

[0062] Specifically, in the above S1, the purpose of the first homogenization treatment is to make the harmful phase laves phase in the iron-nickel-based superalloy ingot completely dissolve but not initial melting, otherwise it will make the plasticity of the ingot worse and cause cracking during the breakdown process; therefore, the range of T0 is controlled at 1140-1160℃.

[0063] Specifically, in the above S1, the first short-time high-temperature homogenization treatment is to appropriately eliminate part of the dendritic segregation in the ingot, but some dendrites are still left, which become recrystallization nucleation points in the subsequent pre-upsetting process, which is beneficial to recrystallization.

[0064] Specifically, in the above S2, the purpose of pre-upsetting is: 1. breaking part of columnar crystals; 2. reducing the residual interdendritic spacing through the compression effect of pre-upsetting, reducing the diffusion distance of segregation elements, thereby facilitating the rapid diffusion in the next step; 3. causing partial dynamic recrystallization of the as-cast grain boundaries, interdendritic spacing of residual dendrites, and carbide vicinity. When the deformation amount of pre-upsetting is too large, the ingot is prone to cracking; when the deformation amount is too small, the effect of reducing the interdendritic spacing of residual dendrites cannot be achieved, thereby failing to reduce the diffusion distance of segregation elements. When the deformation rate of pre-upsetting is too large, the risk coefficient of ingot cracking is increased; when the deformation rate is too small, on the one hand, the ingot cools quickly, resulting in low temperature, and therefore the required upsetting force is significantly increased; on the other hand, the ingot is prone to cold cracking, causing the ingot to be scrapped. Therefore, the deformation amount of pre-upsetting is controlled to be 10% to 30% (for example, the deformation amount can be 10%, 15%, 20%, 25%, 30%, etc.), and the deformation rate of pre-upsetting is controlled to be 0.001 to 0.01 s -1 (for example, the deformation rate can be 0.002 s -1 , 0.005 s -1 , 0.008 s -1 , etc.).

[0065] Specifically, in the above S2, the diffusion distance of segregation elements is significantly shortened after pre-upsetting, and the efficiency of segregation elimination is improved after the second short-time high-temperature homogenization treatment, and the dispersed recrystallized structure is fully subjected to static recrystallization, further breaking the organization inheritance of columnar crystals.

[0066] Specifically, in the above S3, the temperature is lowered to T0-ΔT1 and held for at least 2 h before being discharged, ensuring that the temperature of the ingot is uniform from the surface to the center.

[0067] Specifically, in the above S3, the deformation amount of the first upsetting is greater than that of the pre-upsetting.

[0068] Specifically, in the above S3, the deformation amount of the first upsetting is too large, increasing the risk of ingot cracking, and too small, failing to break the as-cast grains, resulting in poor effect and affecting the final performance; the deformation rate of the first upsetting is too large, causing the ingot to crack easily, and too small, significantly increasing the upsetting force and the risk of ingot cracking. Therefore, the deformation amount of the first upsetting is controlled to be 30% to 40% (for example, the deformation amount can be 30%, 35%, 40%, etc.), the deformation rate of the first upsetting is controlled to be 0.001 to 0.01 s -1 (for example, the deformation rate can be 0.002 s -1 , 0.005 s -1 , 0.008 s -1 , etc.), and the final forging temperature of the first upsetting is controlled to be above 950°C, for example, 950 to 1000°C. After the first upsetting, the recrystallization ratio of the ingot is greatly improved, and a uniform open-die structure can be obtained through subsequent elongation processes.

[0069] Specifically, the holding temperature in the first short-time high-temperature homogenization treatment should not be too low, otherwise the diffusion of the segregated elements will be adversely affected; the holding time should not be too long, therefore, an appropriate time should be selected so that a portion of the dendritic structure remains in the ingot; the holding time of the first homogenization treatment is t0, the holding time of the first short-time high-temperature homogenization treatment is t1, and the holding time of the second short-time high-temperature homogenization treatment is t2; the inventors have conducted in-depth research and found that the holding times and the ingot diameter should satisfy the following relationships:

[0070] when the ingot diameter is 300-400 mm, t0 is 14-17 h, t1 is 14-17 h, and t2 is 17-20 h;

[0071] when the ingot diameter is 400-500 mm, t0 is 17-20 h, t1 is 17-20 h, and t2 is 20-23 h;

[0072] when the ingot diameter is 500-600 mm, t0 is 20-24 h, t1 is 20-24 h, and t2 is 23-27 h;

[0073] when the ingot diameter is 600-700 mm, t0 is 24-28 h, t1 is 24-28 h, and t2 is 27-31 h;

[0074] when the ingot diameter is 700-800 mm, t0 is 28-34 h, t1 is 28-34 h, and t2 is 31-37 h;

[0075] when the ingot diameter is 800-900 mm, t0 is 34-40 h, t1 is 34-40 h, and t2 is 37-43 h;

[0076] when the ingot diameter is 900 mm, t0 is ≥40 h, t1 is ≥40 h, and t2 is ≥43 h.

[0077] Specifically, in S4, the deformation amount of the first elongation is too large, the risk of cracking is high, and the ends are prone to have a necking phenomenon; the deformation amount is too small to reach the critical deformation amount required for dynamic recrystallization. The deformation rate of the first elongation is too large, on the one hand, the blank is prone to cracking, and on the other hand, for large-size blanks, the outer surface has a lower temperature due to temperature drop, and the core has a temperature rise under a large deformation rate, resulting in a large difference in the structure between the inside and outside of the blank. The deformation rate of the first elongation is too small, due to the temperature drop, the number of heating times needs to be increased to complete the elongation process, resulting in grain growth of the portion that has been elongated, and the portion that is newly elongated has a fine structure. Therefore, the deformation amount of the first elongation is controlled to be 20%-40%, the deformation rate of the first elongation is controlled to be 0.01-0.1 s -1 , and the final forging temperature is controlled to be above 950℃.

[0078] Specifically, in the above S4, the ingot after the first elongation is completed to change the as-cast structure to the as-forged structure.

[0079] Specifically, in the above S5, the temperature of the second upsetting is lower than that of the first upsetting, which is beneficial to the control of fine grains.

[0080] Specifically, in the above S5, the deformation amount of the second upsetting is too large, and the blank is prone to cracking. If the deformation amount of the second upsetting is too small, the upsetting is not transparent, and dynamic recrystallization cannot be achieved because the required deformation amount for dynamic recrystallization is not reached. If the deformation rate of the second upsetting is too large, the blank is prone to cracking; if the deformation rate of the second upsetting is too small, the temperature drop at both ends is large, which causes the end to be prone to cracking. Therefore, the deformation amount of the second upsetting is controlled to be 30% to 40%, the deformation rate of the second upsetting is controlled to be 0.01 to 0.1 s -1 , and the final forging temperature is controlled to be above 950°C.

[0081] Specifically, in the above S6, the second elongation is the final forming pass, and if the deformation amount is too large, cracking is prone to occur, or the internal and external structures are not uniform, and if the deformation amount is too small, the critical deformation amount for dynamic recrystallization is not reached, and the effect of recrystallization refinement cannot be effectively achieved. If the deformation rate of the second elongation is too large, cracking is prone to occur, causing the final product to be scrapped; if the deformation rate is too small, the temperature is too low due to the temperature drop, and the effect of dynamic recrystallization refinement through one pass elongation cannot be achieved. Therefore, the deformation amount of the second elongation is controlled to be 30% to 40%, the deformation rate of the second elongation is controlled to be 0.01 to 0.1 s -1 , and the final forging temperature is controlled to be above 930°C. During the second elongation, the temperature is lower and the deformation amount is larger, which is beneficial to achieving a uniform and fine-grained structure.

[0082] Specifically, the above upsetting and elongation operations can be performed on a fast-forging hydraulic press or a water press.

[0083] Specifically, after the above S6, the obtained structure has fine and uniform grains, for example, the grain size is finer than 5 levels, and the maximum grain size difference is not more than 3 levels.

[0084] Compared with the prior art, the iron-nickel-based superalloy ingot homogenization cogging method of the present application firstly eliminates low-melting-point phases in the alloy by adopting primary homogenization treatment, then carries out first short-time high-temperature homogenization treatment to eliminate part of segregation but still leave some dendrites, which become recrystallization nucleation points in the pre-upsetting process and are beneficial to recrystallization; the diffusion distance of segregation elements is obviously shortened after pre-upsetting, and second short-time high-temperature homogenization treatment is carried out after pre-upsetting, which improves the segregation elimination efficiency and enables dispersed recrystallized structure to fully statically recrystallize, further breaking the columnar crystal organization inheritance; two-up two-down is carried out in a narrow temperature range, and the temperature is sequentially lowered in each fire to ensure that each or after completion, finer grain structure is obtained than the previous fire. The last fire is elongated by means of large deformation + low temperature deformation to ensure the uniform fine-grained structure. The method of the present application combines homogenization annealing and upsetting process by precisely controlling the sequence of each process and the process parameters of each step, thereby improving the efficiency and quality of large-size iron-nickel-based superalloy ingot homogenization cogging. By adopting two-up two-down forging in a narrow temperature range with sequential temperature lowering, the uniform fine-grained rod structure is obtained.

[0085] The method of the present application obtains a structure with fine and uniform grains, for example, the grain size is finer than 5 levels, and the maximum grain size difference is not more than 3 levels, for example, the maximum grain size difference of an iron-nickel-based superalloy ingot with a diameter of less than 550 mm after being treated by the method is not more than 2 levels.

[0086] Example 1

[0087] The present embodiment provides an iron-nickel-based superalloy ingot homogenization cogging method, comprising:

[0088] Step 1: The Φ508mm GH4169 alloy ingot obtained by vacuum induction melting + vacuum consumable remelting dual process is subjected to homogenization annealing treatment, and the homogenization process includes primary homogenization and first short-time high-temperature homogenization, the primary homogenization is 1160℃ for 24h, and the first short-time high-temperature homogenization is 1200℃ for 20h;

[0089] Step 2: The furnace temperature is lowered to 1120℃ for 6h, and then the ingot is pre-upset, the pre-upsetting deformation is 15%, and the deformation rate is 0.008s -1 ;

[0090] Step 3: The pre-upset ingot is reheated and kept at 1180℃ for 25h, and the grain structure after the end of the keeping is shown in Figure 1 ; After the temperature is lowered to 1120℃ for 6h, the ingot is first upset, the upsetting deformation is 35%, and the deformation rate is 0.01s -1 ;

[0091] Step 4, the ingot after the first upsetting is reheated and kept at 1110℃ for 6h, and then is taken out to perform the first elongation, the deformation amount of the first elongation is 40%, and the elongation deformation rate is controlled to be 0.02s -1 , the grain structure after the first elongation is shown in Figure 2 ;

[0092] Step 5, the ingot after the first elongation is reheated and kept at 1090℃ for 6h, and then is taken out to perform the second upsetting, the upsetting deformation amount of the second upsetting is 30%, and the upsetting deformation rate is controlled to be 0.01s -1 , the final forging temperature is controlled to be above 950℃;

[0093] Step 6, the ingot after the second upsetting is reheated and kept at 1060℃ for 6h, and then is taken out to perform the second elongation, the deformation amount of the second elongation is 35%, and the elongation deformation rate is controlled to be 0.05s -1 , the final forging temperature is controlled to be above 930℃.

[0094] The grain size in the 0.5R (the area within 0.5 times the radius on the cross section of the rod) of the rod after the breaking down in the embodiment reaches 5.5, the grain structure is shown in Figure 3 , the grains are uniform, and the maximum grain size difference in different parts is 2. No cracks occur in the production process in the embodiment, and the finished product rate is high.

[0095] Embodiment 2

[0096] The embodiment provides a uniformizing breaking down method for an iron-nickel-based high-temperature alloy ingot, and the method comprises the following steps:

[0097] Step 1, a Φ620mm GH4706 alloy ingot obtained through a vacuum induction melting+vacuum self-consumption remelting double process is subjected to homogenizing annealing treatment, the homogenizing process comprises primary homogenizing and first short-time high-temperature homogenizing, the primary homogenizing treatment process is kept at 1160℃ for 27h, and the first short-time high-temperature homogenizing is kept at 1190℃ for 25h;

[0098] Step 2, the furnace temperature is reduced to 1140℃ and kept for 8h, and then the ingot is subjected to pre-upsetting, the pre-upsetting deformation amount is 18%, and the deformation rate is 0.006s -1 ;

[0099] Step 3, the ingot after the pre-upsetting is reheated and kept at 1200℃ for 27h, and then is taken out, the grain structure after the keeping is shown in Figure 4 ; the temperature is reduced to 1140℃ and kept for 8h, and then the ingot is taken out to perform the first upsetting, the upsetting deformation amount is 35%, and the deformation rate is 0.005s-1 ;

[0100] Step 4, the ingot after the first upsetting is reheated, the reheating temperature is 1120℃, the reheating is kept for 8h, then the first elongation is performed, the elongation deformation is 40%, the elongation deformation rate is controlled at 0.01s -1 , the final forging temperature is controlled at 950℃ or above, the grain structure after the first elongation is shown in Figure 5 ;

[0101] Step 5, the ingot after the first elongation is reheated, the reheating temperature is 1100℃, the reheating is kept for 8h, then the second upsetting is performed, the upsetting deformation is 30%, the upsetting deformation rate is controlled at 0.01s -1 , the final forging temperature is controlled at 950℃ or above;

[0102] Step 6, the ingot after the second upsetting is reheated, the reheating temperature is 1070℃, the reheating is kept for 8h, then the second elongation is performed, the elongation deformation is 40%, the elongation deformation rate is controlled at 0.03s -1 , the final forging temperature is controlled at 930℃ or above.

[0103] The grain size of the rod within 0.5R after the breaking down in the embodiment reaches level 5, the grain structure is shown in Figure 6 , the grains are uniform, and the maximum grain size difference of different parts is level 3. No cracks occur in the production process of the embodiment, and the finished product rate is high.

[0104] Embodiment 3

[0105] The embodiment provides a uniformizing breaking down method for a Fe-Ni-based high-temperature alloy ingot, comprising:

[0106] Step 1, a Φ406mm GH4169 gold ingot obtained by a vacuum induction melting+protective atmosphere electroslag remelting+vacuum consumable remelting three-process smelting is subjected to homogenizing annealing treatment, the homogenizing process comprises primary homogenizing and first short-time high-temperature homogenizing, the primary homogenizing is kept at 1160℃ for 18h, and the first short-time high-temperature homogenizing is kept at 1200℃ for 18h;

[0107] Step 2, the furnace temperature is reduced to 1120℃ and kept, and the ingot is kept for 5h, then the ingot is pre-upset, the pre-upsetting deformation is 18%, and the deformation rate is 0.006s -1 ;

[0108] Step 3, the ingot after the pre-upsetting is reheated, the reheating temperature is 1190℃, the reheating time is 20h, and the grain structure after the reheating is shown in Figure 7; the temperature is decreased to 1130 DEG C and kept for 5h, then the ingot is taken out of the furnace, the ingot is first upset, the upsetting deformation is 36%, and the upsetting deformation rate is 0.006s -1 ;

[0109] Step 4, the ingot after the first upsetting is taken out of the furnace and kept for 5h, then the ingot is drawn, the drawing deformation is 35%, and the drawing deformation rate is controlled to be 0.05s -1 ;

[0110] Step 5, the ingot after the first drawing is taken out of the furnace and kept for 5h, then the ingot is secondly upset, the upsetting deformation is 30%, and the upsetting deformation rate is controlled to be 0.03s -1 , and the final forging temperature is controlled to be above 950 DEG C;

[0111] Step 6, the ingot after the second upsetting is taken out of the furnace and kept for 5h, then the ingot is secondly drawn, the drawing deformation is 35%, and the drawing deformation rate is controlled to be 0.03s -1 , and the final forging temperature is controlled to be above 930 DEG C.

[0112] The grain size of the rod after the breaking down in the embodiment is controlled to be 7 levels, and the grain structure is shown in Figure 8 The grain is uniform, and the maximum grain size level difference of different parts is 2 levels. In the production process of the embodiment, no cracks occur, and the finished product rate is high.

[0113] Embodiment 4

[0114] The embodiment provides a uniformizing breaking down method for a Fe-Ni-based high-temperature alloy ingot, and the method comprises the following steps:

[0115] Step 1, a Φ350mm GH4169 alloy ingot obtained through a vacuum induction melting+vacuum self-consumption remelting double process is subjected to homogenizing annealing treatment, and the homogenizing process comprises primary homogenization and first short-time high-temperature homogenization, the primary homogenization is kept at 1160 DEG C for 16h, and the first short-time high-temperature homogenization is kept at 1200 DEG C for 15h;

[0116] Step 2, the furnace temperature is decreased to 1140 DEG C and kept, and the ingot is kept for 4h, then the ingot is pre-upset, the pre-upsetting deformation is 16%, and the deformation rate is 0.008s -1 ;

[0117] Step 3, the ingot after the pre-upsetting is taken out of the furnace and kept, the keeping temperature is 1190 DEG C, and the keeping time is 20h, and the grain structure after the keeping is shown in Figure 9 ; the temperature is decreased to 1140 DEG C and kept for 4h, then the ingot is taken out of the furnace, the ingot is first upset, the upsetting deformation is 30%, and the upsetting deformation rate is 0.005s-1 ;

[0118] Step 4: Return the ingot after the first upsetting to the furnace for heat treatment at 1120℃ for 4 hours. Then, remove it from the furnace for drawing, with a drawing deformation of 35% and a drawing deformation rate controlled at 0.04s. -1 ;

[0119] Step 5: Return the ingot, after the first drawing, to the furnace for heat treatment at 1100℃ for 4 hours. Then, remove it from the furnace for a second upsetting, with an upsetting deformation of 33% and an upsetting deformation rate controlled at 0.04s. -1 The final forging temperature is controlled above 950℃;

[0120] Step 6: Return the ingot after the second upsetting to the furnace for heat treatment at 1070℃ for 4 hours. Then, remove it from the furnace for the second drawing process. The drawing deformation should be 34%, and the drawing deformation rate should be controlled at 0.05s. -1 The final forging temperature is controlled above 930℃.

[0121] In this embodiment, after billet preparation, the grain size of the bar stock within 0.5R reached level 7, and its grain structure is shown in the figure. Figure 10 The grains are uniform, with a maximum grain size difference of only one grade in different locations. No cracks occurred during the production process in this embodiment, resulting in a high yield.

[0122] Example 5

[0123] This embodiment provides a method for homogenizing the billet preparation of iron-nickel-based superalloy ingots, including:

[0124] Step 1: The 495mm GH4706 alloy ingot obtained by the dual process of vacuum induction melting + protective atmosphere electroslag remelting + vacuum arc remelting is subjected to homogenization annealing treatment. The homogenization process includes primary homogenization and the first short-time high-temperature homogenization. The primary homogenization is held at 1150℃ for 17h, and the first short-time high-temperature homogenization is held at 1190℃ for 18h.

[0125] Step 2: Reduce the furnace temperature to 1130℃ and hold for 5 hours. Then, pre-upset the ingot, with a pre-upsetting deformation of 17% and a deformation rate of 0.007s. -1 ;

[0126] Step 3: After pre-upsetting, the ingot is returned to the furnace for heat treatment at 1190℃ for 22 hours. After the heat treatment, its grain structure is as follows: Figure 11 After the temperature was lowered to 1130℃ and held for 5 hours, the ingot was removed from the furnace and subjected to its first upsetting. The upsetting deformation was 32% and the deformation rate was 0.007s. -1 ;

[0127] Step 4, the ingot after the first upsetting is reheated and kept at a temperature of 1110℃ for 5h, then is taken out to be elongated, the elongation deformation is 37%, and the elongation deformation rate is controlled at 0.04s -1 ;

[0128] Step 5, the ingot after the first elongation is reheated and kept at a temperature of 1090℃ for 5h, then is taken out to be upsetted for the second time, the upsetting deformation is 32%, and the upsetting deformation rate is controlled at 0.01s -1 , and the final forging temperature is controlled above 950℃;

[0129] Step 6, the ingot after the second upsetting is reheated and kept at a temperature of 1070℃ for 5h, then is taken out to be elongated for the second time, the elongation deformation is 37%, and the elongation deformation rate is controlled at 0.07s -1 , and the final forging temperature is controlled above 930℃.

[0130] The grain size of the rod within 0.5R after the breakdown of the embodiment is controlled at level 6, and the grain structure thereof is shown in Figure 12 , the grains are uniform, and the maximum grain size difference of different parts is level 2. No cracks occur in the production process of the embodiment, and the finished product rate is high.

[0131] In addition to the above embodiments, the present application can also have other implementation manners, and any technical method formed by equivalent replacement or equivalence falls within the protection scope required by the present application.

[0132] The inventor has carried out a large number of researches in the research process, and some of the schemes with poor effects are listed as the following comparative examples:

[0133] Comparative Example 1

[0134] The present comparative example provides a kind of iron-nickel-based superalloy ingot breakdown method, comprising:

[0135] Step 1, the Φ508mm GH4169 alloy ingot obtained by vacuum induction melting + vacuum self-consumption remelting double process is subjected to homogenization annealing treatment, the homogenization process is that the ingot is heated to 1160℃ with furnace and kept for 24h, then heated to 1200℃, kept for 74h, and the temperature is reduced to 1120℃ and kept for 6h, the ingot is subjected to a breakdown process of two upsetting and two elongation, and the specific steps are completely same as the process of the first upsetting, the first elongation, the second upsetting and the second elongation in the embodiment 1. The grain size within 0.5R of the final rod is about level 3, the grains are relatively large, and the grain size is shown in Figure 13 .

[0136] Comparative Example 2

[0137] The present comparative example provides a kind of iron-nickel-based superalloy ingot breakdown method, comprising:

[0138] Step 1, the Φ406mm GH4169 alloy ingot obtained by vacuum induction melting + protective atmosphere electroslag remelting + vacuum consumable remelting triple process is subjected to homogenization annealing treatment, the homogenization process is that the ingot is heated to 1160℃ with furnace, and then heated to 1190℃, and kept for 72h, and then the temperature is reduced to 1120℃ and kept for 5h, and the ingot is subjected to two upsetting and two drawing breakdown processes, and the specific steps are completely same as the processes of the first upsetting, the first drawing, the second upsetting and the second drawing in embodiment 1.

[0139] The grain size of the final rod within 0.5R is about 3.5 grade, and the grain structure is not uniform, and the maximum grain size grade difference of different parts of the cross section is 4 grade, referring to Figure 14 .

[0140] Comparative example 3

[0141] The present comparative example provides a breakdown method of iron-nickel-based high-temperature alloy ingot, comprising:

[0142] The Φ495mm GH4706 nickel-based alloy ingot obtained by vacuum induction melting + protective atmosphere electroslag remelting + vacuum consumable remelting double process is subjected to homogenization annealing treatment, the homogenization process is that the ingot is heated to 1160℃ with furnace, and then heated to 1200℃, and kept for 70h, and then the temperature is reduced to 1120℃ and kept for 5h, and the ingot is subjected to two upsetting and two drawing breakdown processes, and the specific steps are completely same as the processes of the first upsetting, the first drawing, the second upsetting and the second drawing in embodiment 1.

[0143] The final rod within 0.5R is mainly 3.5 grade, and presents mixed crystal structure. The maximum grain size grade difference of different parts is 3 grade, referring to Figure 15 .

[0144] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method of homogenizing and breaking down an iron-nickel-based superalloy ingot, characterized by, The method comprises the following steps: The method comprises the following steps: S1, the ingot is subjected to primary homogenization treatment at T0, and then subjected to first short-time high-temperature homogenization treatment at a temperature higher than T0 by ΔT1; wherein ΔT1=20-40℃; S2, the ingot is subjected to pre-upsetting at T0-ΔT1 for more than 2 hours, and then taken out of the furnace; S3, the ingot is subjected to second short-time high-temperature homogenization treatment at T0+ΔT2, and then taken out of the furnace after the temperature is lowered to T0-ΔT1 for at least 2 hours; ΔT2=0-40℃; S4, the ingot is subjected to first upsetting at T0-ΔT3 for more than 2 hours, and then taken out of the furnace; ΔT3=40-60℃; S5, the ingot is subjected to second upsetting at T0-ΔT4 for more than 2 hours, and then taken out of the furnace; ΔT4=60-80℃; S6, the ingot is subjected to second drawing at T0-ΔT5 for more than 2 hours, and then taken out of the furnace to obtain b; ΔT5=80-110℃; T0 is controlled to be 1140-1160℃. In S6, the deformation of the second drawing is 30%-40%. In the S2, the deformation amount of the pre-upsetting is 10% to 30%; the deformation rate of the pre-upsetting is 0.001 to 0.01 s -1 ; In S2, the deformation of the pre-upsetting is 15%-30%.

2. The Fe-Ni-based superalloy ingot homogenization breakdown method according to claim 1, characterized in that, In S3, the deformation of the first upsetting is greater than that of the pre-upsetting.

3. The Fe-Ni-based superalloy ingot homogenization breakdown method according to claim 2, characterized in that, The deformation rate of the pre-upsetting in S2 is 0.001-0.008 s -1 .

4. The Fe-Ni based superalloy ingot homogenization breakdown method according to claim 1, characterized in that, In S3, the deformation of the first upsetting is 30%-40%.

5. The Fe-Ni-based superalloy ingot homogenization breakdown method according to claim 4, characterized in that, The homogenization time of the primary homogenization treatment is t0, the homogenization time of the first short-time high-temperature homogenization treatment is t1, and the homogenization time of the second short-time high-temperature homogenization treatment is t2; the above homogenization times and the diameter of the ingot satisfy the following relationships:

6. The Fe-Ni-based superalloy ingot homogenization breakdown method according to claim 5, characterized in that, In the S3, the first upsetting is controlled at a deformation rate of 0.001 to 0.01 s -1 .

7. The Fe-Ni based superalloy ingot homogenization breakdown method according to claim 1, characterized in that, When the diameter of the ingot is 300-400mm, t0 is 14-17h, t1 is 14-17h, and t2 is 17-20h; When the diameter of the ingot is 400-500mm, t0 is 17-20h, t1 is 17-20h, and t2 is 20-23h; When the diameter of the ingot is 500-600mm, t0 is 20-24h, t1 is 20-24h, and t2 is 23-27h; When the diameter of the ingot is 600-700mm, t0 is 24-28h, t1 is 24-28h, and t2 is 27-31h; When the diameter of the ingot is 700-800mm, t0 is 28-34h, t1 is 28-34h, and t2 is 31-37h; When the diameter of the ingot is 800-900mm, t0 is 34-40h, t1 is 34-40h, and t2 is 37-43h; ​ The ingot diameter is 900 mm, t0≥40 h, t1≥40 h, and t2≥43 h.

8. The Fe-Ni based superalloy ingot homogenization breakdown method according to claim 1, characterized in that, In the S4, the deformation amount of the first elongation is 20% to 40%.

9. The iron-nickel based superalloy ingot homogenization breakdown method according to any one of claims 1 to 8, characterized in that, In the S5, the deformation amount of the second upsetting is 30% to 40%.

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