Super-large ingot type high-temperature alloy forging material and preparation method thereof

Abstract

The invention relates to the technical field of high-temperature alloys, and provides a preparation method of an oversized ingot type high-temperature alloy forging material, which comprises the following steps: S1, heating a high-temperature alloy ingot; s2, the high-temperature alloy cast ingot obtained in the step S1 is subjected to pre-deformation, wherein pre-deformation comprises upsetting and drawing-out which are conducted in sequence; s3, the pre-deformed high-temperature alloy cast ingot is subjected to homogenizing heat treatment; s4, performing cogging thermal deformation on the high-temperature alloy ingot subjected to the homogenizing heat treatment; and S5, the forging stock obtained in the step S4 is cooled and then subjected to heat treatment, and finally radial forging is conducted. According to the preparation method of the high-temperature alloy forged material, firstly, a large-size high-temperature alloy cast ingot is subjected to pre-deformation with the small deformation amount, and then homogenization heat treatment is conducted at the high temperature, so that segregation phases in the cast ingot are redissolved, segregation elements are diffused, and the high-temperature alloy forged material is obtained. And after homogenization, the high-temperature alloy cast ingot is subjected to fast forging and radial forging, and the high-temperature alloy bar with the uniform structure is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature alloys, and particularly relates to an ultra-large ingot type high-temperature alloy forging material and a preparation method thereof. BACKGROUND

[0002] The high-temperature alloy has good mechanical properties and heat corrosion resistance, and is widely applied in the fields of aerospace, gas turbine and nuclear industry, and can be used to prepare high-temperature components such as turbine discs, combustion chambers, fasteners and energy conversion devices. In recent years, the development of the aero-engine further promotes the development of the high-temperature alloy; for example, the thrust-to-weight ratio of the aero-engine is getting larger and larger, so the service temperature of the high-temperature components is getting higher and higher, the single-stage load is continuously increasing, and the stress level of the parts is getting higher and higher.

[0003] In order to cope with the increasingly severe service environment, the alloying degree of the high-temperature alloy is continuously improved, so as to obtain better mechanical properties and temperature resistance. However, the high-temperature alloy with high alloying degree inevitably has micro-segregation in the solidification process, forms dendritic morphology and segregation phases, and the larger the size of the ingot is, the more serious the segregation is. The segregation phase consumes a large amount of strengthening elements in the matrix, and the brittle phase with a low melting point reduces the plasticity of the ingot, so that the hot working with a large deformation cannot be realized, and then the microstructure and the regulation of the segregation phase are affected.

[0004] At the same time, the design trend of the engine is that the part structure is increasingly complex, and the part size is getting larger and larger, so the ultra-large specification high-temperature alloy ingot must be prepared, and then the large-size deformed high-temperature alloy forging rod is prepared, so that the disc forging product with gradually increasing diameter can be produced. With the increasing product specification, the regulation of the microstructure and the precipitated phase of the high-temperature alloy is more and more difficult.

[0005] Currently, the main method for preparing high-temperature alloys involves subjecting the ingot to a prolonged high-temperature annealing heat treatment at a relatively high temperature before hot deformation. This process ensures complete dissolution of segregated phases and uniform diffusion of segregated elements before large-deformation forging. However, when dealing with ultra-large ingot-shaped high-temperature alloys, severe segregation necessitates lengthy high-temperature annealing heat treatment to achieve elemental homogenization. For example, Chinese Patent CN202411108942 discloses a method for preparing φ150mm bars from a φ510mm ingot. The homogenization heat treatment process involves holding the ingot at 1160℃ for 35 hours, then raising the temperature to 1200℃ and holding it for 40 hours, followed by furnace cooling to 1100℃ and then air cooling. Chinese patent CN202411719262 discloses a process for preparing φ400mm bars from φ508mm electroslag ingots. Before forging, the ingot undergoes a prolonged, segmented high-temperature annealing heat treatment: the φ508mm electroslag ingot is held at 740℃ for 8 hours, then heated to 1160℃ at a rate of 70℃ / h and held for 25 hours, followed by a heating to 1189℃ at a rate of 70℃ / h and held for 110 hours, then cooled to 1085℃ at a rate of 50℃ / h and held for 4 hours, and finally air-cooled. After forging, a finished forged bar with a diameter of φ400mm is obtained. Currently, there are few methods for preparing deformed high-temperature alloy forged bars with ingots larger than φ600mm.

[0006] Currently, the preparation methods for ultra-large ingot-shaped (>φ600mm) wrought superalloy forged bars are still immature, resulting in problems such as lengthy heat treatment, high energy consumption, severe material oxidation, and low yield of finished products. Therefore, it is necessary to study an efficient preparation method for ultra-large ingot-shaped wrought superalloy forged bars. Summary of the Invention

[0007] The technical problem solved by this invention is to provide a method for preparing ultra-large ingot-shaped high-temperature alloy forgings. The preparation method provided by this application can prepare large-sized high-temperature alloy forgings with uniform microstructure and a short preparation time.

[0008] In view of this, this application provides a method for preparing ultra-large ingot-shaped high-temperature alloy forgings, comprising the following steps:

[0009] S1. Heating the high-temperature alloy ingot;

[0010] S2. Pre-deform the high-temperature alloy ingot obtained in step S1, wherein the pre-deformation includes upsetting and drawing in sequence.

[0011] When T 1max -T 1min At temperatures above 100℃, the upsetting deformation ε0 is 1 / 3ε c ~2 / 3ε cThe elongation deformation ε0' is 1 / 3ε c ~2 / 3ε c When the surface temperature of the ingot decreases to (T 1min Before pre-deformation is completed at +20℃, the furnace is reheated for 1-2 hours.

[0012] When T 1max -T 1min At ≤100℃, the upsetting deformation ε0 is 1 / 3ε c ~1 / 2ε c The elongation deformation ε0' is 1 / 3ε c ~1 / 2ε c After the upsetting process is completed, the surface of the upset ingot is wrapped with insulating cotton and then returned to the furnace for insulation.

[0013] S3. The pre-deformed high-temperature alloy ingot is subjected to homogenization heat treatment.

[0014] For T p <T s The high-temperature alloy, wherein the homogenization heat treatment specifically comprises:

[0015] The high-temperature alloy ingot is placed in a heat treatment furnace of T1 and heated to T. h1 Hold at temperature t1, then raise the temperature to T. h2 Keep warm and then cool;

[0016] For T p ≥T s The high-temperature alloy, wherein the homogenization heat treatment specifically comprises:

[0017] The high-temperature alloy ingot is placed in a heat treatment furnace of T1 and heated to T. h2 Keep warm and then cool;

[0018] S4. The high-temperature alloy ingot after homogenization heat treatment is subjected to billet hot deformation, with a total deformation of 1 / 3ε. c ~3 / 4ε c ;

[0019] S5. After cooling the forging billet obtained in step S4, perform heat treatment and finally radial forging.

[0020] The heat distortion temperature range is T. 1min ~T 1max Critical deformation ε for cracking c Maximum safe remelting temperature of precipitated phase T P Equilibrium solid-liquid phase temperature T s ;

[0021] T 1min ≤T1≤T 1max T h1The range of values ​​for is (T) p -50℃)~(T p -10℃), t1=Aexp(-0.0186T h1 The value of A is in the range of 1.5 * 10^6. 10 ~5*10 10 ;T h2 The range of values ​​for is (T) s -100℃)~(T s -10℃).

[0022] In some specific embodiments, in step S1, the heating specifically involves:

[0023] When T 1max -T 1min >100℃, place the high-temperature alloy ingot in the T1 heat treatment furnace and hold for 3~5 hours;

[0024] When T 1max -T 1min At ≤100℃, place the high-temperature alloy ingot in a T1 heat treatment furnace and hold it for 3~5 hours. After holding, wrap the ingot with insulation cotton and continue to hold it in a T1 heat treatment furnace for 1~2 hours.

[0025] In some specific embodiments, in step S3, for T p <T s High-temperature alloys, T1 heated to T h1 The heating rate is 50~100℃ / h, T h1 Heat up to T h2 The heating rate is 20~100℃ / h; and / or, the temperature is increased to T. h2 The heat preservation time is 36~90 hours.

[0026] In some specific embodiments, in step S3, for T p ≥T s High-temperature alloys, T1 heated to T h2 The heating rate is 20~100℃ / h; and / or, the temperature is increased to T. h2 The heat preservation time is 24~72h.

[0027] In some specific embodiments, in step S3, the cooling method is specifically: furnace cooling to below 700°C followed by air cooling.

[0028] In some specific embodiments, in step S4, the hot deformation of the billet is performed by four upsetting and four drawing processes with seven heating cycles, and the heating temperature before each upsetting and drawing is T. 1min ~T1, keep warm for 2~4 hours.

[0029] In some specific embodiments, in step S5, the cooling specifically involves air cooling to a surface temperature below 100°C for the high-temperature alloy ingot; and / or, the heat treatment temperature is T2, and the holding time is 3~5 hours, wherein T2 ≥ T1 - 200°C; and / or, the radial forging includes multiple passes, with the forging frequency of each pass controlled at 60~240 times / min, and the total deformation controlled at 1 / 3ε. c ~3 / 4ε c .

[0030] In some specific embodiments, the diameter of the high-temperature alloy ingot is >600mm, and the diameter of the high-temperature alloy forging is ≥350mm;

[0031] And / or, the high-temperature alloy ingot includes GH4169, GH2909 or GH738.

[0032] This application also provides high-temperature alloy forgings prepared by the preparation method described above.

[0033] In some specific embodiments, the grain size from the edge to the center of the high-temperature alloy forging is grade 4.5~5, grade 6.5~7.5, and grade 7~7.5, with grade differences of 0.5, 1, and 0.5, respectively.

[0034] This application provides a method for preparing ultra-large ingot-shaped high-temperature alloy forgings. First, the high-temperature alloy ingot is held at a certain temperature. Then, the ingot is pre-deformed under specific conditions. Next, the pre-deformed ingot undergoes homogenization heat treatment. Finally, the ingot is subjected to rapid forging and radial forging, ultimately yielding large-size high-temperature alloy forgings with uniform diffusion of segregated elements and a homogeneous microstructure. In this method, the large-size high-temperature alloy ingot is first pre-deformed with a small deformation to crush large-size segregated phases, preventing cracking of the high-temperature alloy in a segregated state during pre-deformation. Then, homogenization heat treatment is performed at a higher temperature to dissolve the segregated phases in the ingot and diffuse the segregated elements, ensuring the uniformity of the microstructure. Simultaneously, a reasonable homogenization heat treatment temperature and time are determined based on the composition of the high-temperature alloy to shorten the preparation time. Compared to the multi-stage high-temperature homogenization heat treatment in existing technologies, this application uses a combination of pre-deformation and homogenization treatment, which can significantly shorten the homogenization time, reduce energy consumption, reduce material oxidation and cracking during the preparation process, and improve the yield of finished products. Attached Figure Description

[0035] Figure 1 The image shows the metallographic structure of the high-temperature alloy forging prepared in Example 1 of this invention.

[0036] Figure 2 A metallographic photograph of the high-temperature alloy forging prepared in Comparative Example 1 of this invention;

[0037] Figure 3 The image shows the metallographic structure of the high-temperature alloy forging prepared in Example 2 of this invention.

[0038] Figure 4 This is a metallographic photograph of the high-temperature alloy forging prepared in Example 3 of the present invention. Detailed Implementation

[0039] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0040] To address the problems of severe segregation in ultra-large ingot-shaped high-temperature alloy castings (>φ600mm), which are difficult to homogenize compared to smaller ingots, leading to difficulties in controlling the microstructure and precipitated phases during subsequent hot deformation, as well as long homogenization time, high energy consumption, severe oxidation, and low yield of finished products, this application provides a method for preparing ultra-large ingot-shaped high-temperature alloy forgings. The method involves first performing a small-scale pre-deformation, followed by homogenization heat treatment at a higher temperature to dissolve the segregated phases and diffuse the segregated elements. After homogenization, the high-temperature alloy ingot is subjected to rapid forging and radial forging to obtain the finished high-temperature alloy forging. This alloy forging exhibits dispersed segregated phases, a uniform microstructure, and significantly reduced preparation time. Specifically, this invention discloses a method for preparing ultra-large ingot-shaped high-temperature alloy forgings, including the following steps:

[0041] S1. Heating the high-temperature alloy ingot;

[0042] S2. Pre-deform the high-temperature alloy ingot obtained in step S1, wherein the pre-deformation includes upsetting and drawing in sequence.

[0043] When T 1max -T 1min At temperatures above 100℃, the upsetting deformation ε0 is 1 / 3ε c ~2 / 3ε c The elongation deformation ε0' is 1 / 3ε c ~2 / 3ε c When the surface temperature of the ingot decreases to (T 1min Before pre-deformation is completed at +20℃, the furnace is reheated for 1-2 hours.

[0044] When T 1max -T 1min At ≤100℃, the upsetting deformation ε0 is 1 / 3ε c ~1 / 2ε c The elongation deformation ε0' is 1 / 3ε c ~1 / 2ε cAfter the upsetting process is completed, the surface of the upset ingot is wrapped with insulating cotton and then returned to the furnace for insulation.

[0045] S3. The pre-deformed high-temperature alloy ingot is subjected to homogenization heat treatment.

[0046] For T p <T s The high-temperature alloy, wherein the homogenization heat treatment specifically comprises:

[0047] The high-temperature alloy ingot is placed in a heat treatment furnace of T1 and heated to T. h1 Hold at temperature t1, then raise the temperature to T. h2 Keep warm and then cool;

[0048] For T p ≥T s The high-temperature alloy, wherein the homogenization heat treatment specifically comprises:

[0049] The high-temperature alloy ingot is placed in a heat treatment furnace of T1 and heated to T. h2 Keep warm and then cool;

[0050] S4. The high-temperature alloy ingot after homogenization heat treatment is subjected to billet hot deformation, with a total deformation of 1 / 3ε. c ~3 / 4ε c ;

[0051] S5. After cooling the forging billet obtained in step S4, perform heat treatment and finally radial forging.

[0052] The heat distortion temperature range of the high-temperature alloy is T. 1min ~T 1max Critical deformation ε for cracking c Maximum safe remelting temperature of precipitated phase T P The equilibrium solid-liquid phase temperature T of high-temperature alloys s ;

[0053] T 1min ≤T1≤T 1max T h1 The range of values ​​for is (T) p -50℃)~(T p -10℃), t1=Aexp(-0.0186T h1 The value of A is in the range of 1.5 * 10^6. 10 ~5*10 10 ;T h2 The range of values ​​for is (T) s -100℃)~(T s -10℃).

[0054] Based on the composition of the high-temperature alloy, the hot deformation temperature range T of the high-temperature alloy was determined.1min ~T 1max Critical deformation ε for cracking c Maximum safe remelting temperature of precipitated phase T P Equilibrium solid-liquid phase temperature T s Wherein, the critical deformation amount for cracking is the maximum deformation amount that will not cause cracking (or crack initiation) during the plastic deformation of the high-temperature alloy; the equilibrium solid-liquid phase temperature is the temperature range in which the solid and liquid states of the high-temperature alloy coexist under thermodynamic equilibrium conditions; and the maximum safe remelting temperature of the precipitated phase is the upper limit of the remelting temperature of the segregated phase in the high-temperature alloy. The above-mentioned hot deformation temperature range, critical deformation amount for cracking, maximum safe remelting temperature of the precipitated phase, and equilibrium solid-liquid phase temperature are obtained from simulation software and production experience.

[0055] In the process of preparing high-temperature forgings, this application first heats the high-temperature alloy ingot; the preparation method of the high-temperature alloy ingot is in accordance with methods well known to those skilled in the art, and this application has no particular limitations on this; the high-temperature alloy includes GH4169, GH2909, and GH738. The heating specifically involves:

[0056] When T 1max -T 1min >100℃, place the high-temperature alloy ingot in the T1 heat treatment furnace and hold for 3~5 hours;

[0057] When T 1max -T 1min At ≤100℃, place the high-temperature alloy ingot in a T1 heat treatment furnace and hold it for 3~5 hours. After holding, wrap the ingot with insulation cotton and continue to hold it in a T1 heat treatment furnace for 1~2 hours.

[0058] This application then pre-deforms the heated high-temperature alloy ingot. The pre-deformation in this application employs a one-upsetting-one-drawing method. Specifically, the pre-deformation involves:

[0059] When T 1max -T 1min At temperatures above 100℃, the upsetting deformation ε0 is 1 / 3ε c ~2 / 3ε c The elongation deformation ε0' is 1 / 3ε c ~2 / 3ε c When the surface temperature of the ingot decreases to (T 1min Before pre-deformation is completed at +20℃, the furnace is reheated for 1-2 hours.

[0060] When T 1max -T 1min At ≤100℃, the upsetting deformation ε0 is 1 / 3ε c ~1 / 2εc The elongation deformation ε0' is 1 / 3ε c ~1 / 2ε c After the upsetting process is completed, the surface of the upset ingot is wrapped with insulating cotton and then returned to the furnace for insulation.

[0061] For the above T 1max -T 1min For high-temperature alloys with a temperature ≤100℃, the hot deformation temperature range is relatively narrow, resulting in shorter deformation times per deformation. Therefore, after upsetting, insulation cotton is needed for heat preservation, and the deformation amount should be reduced to avoid the temperature dropping after pre-deformation and thus not pre-deforming within the aforementioned deformation temperature range.

[0062] The pre-deformation described in this application uses a smaller deformation amount. The smaller deformation amount can prevent the high-temperature alloy in the segregated state from cracking during the pre-deformation process. However, the pre-deformation process crushes large-sized segregated phase flakes, reduces the degree of segregation of the high-temperature alloy ingot, and is more conducive to the subsequent microstructure and segregated phase control of the high-temperature alloy.

[0063] According to the present invention, the pre-deformed high-temperature alloy ingot is then subjected to homogenization heat treatment, wherein the homogenization heat treatment specifically comprises:

[0064] For T p <T s The high-temperature alloy, wherein the homogenization heat treatment specifically comprises:

[0065] The high-temperature alloy ingot is placed in a heat treatment furnace of T1 and heated to T. h1 Hold at temperature t1, then raise the temperature to T. h2 Keep warm and then cool;

[0066] For T p ≥T s The high-temperature alloy, wherein the homogenization heat treatment specifically comprises:

[0067] The high-temperature alloy ingot is placed in a heat treatment furnace of T1 and heated to T. h2 Keep warm and then cool;

[0068] The pre-deformed high-temperature alloy ingot contains segregated phases, and the distribution of each element has a gradient difference (some elements are enriched in the interdendritic space, and some are enriched in the dendrite trunk). This application uses homogenization heat treatment to achieve the purpose of dissolving the segregated phases and uniformly distributing the elements. For high-temperature alloys with Tp < Ts, the first stage is used to dissolve the segregated phases. During the dissolution process, the segregated elements also diffuse, but the distribution is not yet uniform. Therefore, after the segregated phases are dissolved, the second stage is usually carried out to increase the homogenization temperature and accelerate the diffusion rate of the segregated elements. If the temperature of the first stage homogenization heat treatment is too high, the segregated phases will be overburned during the dissolution process, producing pores and affecting the performance of the high-temperature alloy. If the temperature and time of the second stage homogenization heat treatment are too low, the homogenization will be insufficient, and there will still be a large amount of element segregation, affecting the material properties. If the temperature and time of the second stage homogenization heat treatment are too high, the high-temperature alloy ingot will be in an over-homogeneous state, with obvious grain growth and more oxidation, which will also affect the performance of the high-temperature alloy ingot.

[0069] Specifically, T h1 The range of values ​​for is (T) p -40℃)~(T p The value of A is in the range of 2.0 * 10^2. 10 ~3.5*10 10 ;T h2 The range of values ​​for is (T) s -90℃)~(T s More specifically, T h1 The range of values ​​for is (T) p -30℃)~(T p The value of A is 2.5 * 10. 10 ~3.0*10 10 ;T h2 The range of values ​​for is (T) s -70℃)~(T s ).

[0070] During the above homogenization process, for T p <T s High-temperature alloys, T1 heated to T h1 The heating rate is 50~100℃ / h, T h1 Heat up to T h2 The heating rate is 20~100℃ / h; the temperature is increased to T. h2 The subsequent heat preservation time is 24~72 hours; specifically, T1 is heated to T... h1 The heating rate is 60~90℃ / h, T h1 Heat up to T h2 The heating rate is 30~80℃ / h; the temperature is increased to T h2The subsequent heat preservation time is 30~60 hours; more specifically, the temperature is increased from T1 to T. h1 The heating rate is 70~80℃ / h, T h1 Heat up to T h2 The heating rate is 40~60℃ / h; the temperature is increased to T h2 The subsequent heat preservation time is 36~54 hours.

[0071] For T p ≥T s High-temperature alloys, T1 heated to T h2 The heating rate is 20~100℃ / h; the temperature is increased to T. h2 The heat preservation time is 36~90h; specifically, T1 is heated to T h2 The heating rate is 40~80℃ / h; the temperature is increased to T h2 The heat preservation time is 48~72 hours.

[0072] In the above homogenization heat treatment process, the cooling specifically involves furnace cooling to below 700°C followed by air cooling.

[0073] This application then subjectes the homogenized high-temperature alloy ingot to hot deformation. In this application, the hot deformation employs a four-upsetting and four-drawing process with seven heating cycles. If only one upsetting and one drawing, or two upsetting and two drawing cycles are performed, the ingot cannot be sufficiently deformed, resulting in mixed grains and significant differences in grain size across different areas. The heating temperature before each upsetting and each drawing cycle is T. 1min ~T1, keep warm for 2~4 hours; for T 1max -T 1min For high-temperature alloys ≤100℃, the alloy should be wrapped with insulating cotton before each heat treatment furnace holding. After hot deformation of the billet, the resulting high-temperature alloy forging billet is cooled, specifically by air cooling to a surface temperature below 100℃.

[0074] According to this invention, the high-temperature alloy forging billet is finally heat-treated and then radially forged. Specifically, the heat treatment temperature is T2, and the holding time is 3-5 hours, where T2 ≥ T1 - 200℃. The radial forging specifically employs 4-5 passes, with the forging frequency of each pass controlled at 60-240 times / min, and the total deformation controlled at 1 / 3ε. c ~3 / 4ε c .

[0075] The preparation method provided in this application is mainly for high-temperature alloy ingots with a diameter > 600 mm. After a series of pre-deformation, homogenization heat treatment, billet hot deformation, heat treatment and radial forging processes, the diameter of the obtained high-temperature alloy forging is ≥ 350 mm.

[0076] Furthermore, this application provides a high-temperature alloy forging prepared by the above method.

[0077] In a specific embodiment, the grain size from edge to center of the high-temperature alloy forging prepared in this application is grade 4.5~5, grade 6.5~7.5, and grade 7~7.5, with grade differences of 0.5, 1, and 0.5, respectively.

[0078] This application provides a method for preparing high-temperature alloy forgings. First, a large-sized high-temperature alloy ingot is pre-deformed with a small deformation amount. This small deformation amount avoids cracking of the high-temperature alloy in a segregated state during pre-deformation, but it also breaks down large-sized segregated phases, reducing the degree of segregation in the high-temperature alloy ingot and facilitating subsequent microstructure and segregated phase control. For T... p <T s For high-temperature alloys, the first-stage homogenization heat treatment time range at different homogenization temperatures can be determined by formula, saving time and production costs while ensuring the uniformity of the alloy structure. Compared with the current conventional multi-stage high-temperature homogenization heat treatment method, the pre-deformation + homogenization method can significantly shorten the homogenization time, reduce energy consumption, reduce material oxidation during the preparation process, and improve the yield of finished products.

[0079] To further understand the present invention, the preparation method of the high-temperature alloy forging provided by the present invention will be described in detail below with reference to the embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0080] Example 1

[0081] 1) The Φ660mm high-temperature alloy ingot prepared by vacuum induction-electroslag remelting-vacuum self-consumption has the following chemical composition (wt%): Cr: 18.5, Fe: 18.5, Mo: 3.0, Nb: 5.2, with the remainder being Ni and small amounts of Co, Mn, Al, Si, Ti, etc.

[0082] 2) Based on the composition and tests of the above high-temperature alloy, the hot deformation temperature range of the above high-temperature alloy is 1000℃~1100℃, the critical deformation amount for cracking is 60%, the maximum safe remelting temperature of the precipitated phase is 1150℃, and the equilibrium solid-liquid phase temperature of the high-temperature alloy is 1216℃.

[0083] 3) Hold the high-temperature alloy ingot obtained in step 1) at 1100℃ for 3 hours, then wrap the ingot with insulation cotton and continue to hold it in the furnace for 2 hours.

[0084] 4) Upset the high-temperature alloy ingot, with a deformation of 25%. After upsetting, re-wrap it with insulation cotton, and then heat it in the furnace at 1100℃ for 1.5 hours. After heat treatment, draw it out, with a deformation of 25%.

[0085] 5) The high-temperature alloy ingot after the above pre-deformation is subjected to homogenization heat treatment: the pre-deformed high-temperature alloy ingot is placed in a heat treatment furnace at 1100℃, heated to 1140℃ at a heating rate of 50℃ / h, and held for 16h; then heated to 1190℃ at a heating rate of 50℃ / h and held for 72h; after the holding period, the furnace is cooled to below 700℃ and then removed and air-cooled.

[0086] 6) The homogenized high-temperature alloy ingot is subjected to four upsetting and four drawing hot deformation in seven heat treatments: Before each upsetting or drawing, the ingot is wrapped with heat insulation cotton and kept in a heat treatment furnace at 1020℃~1100℃ for 2~4 hours. After the hot deformation, the high-temperature alloy ingot is forged into a 520mm octagonal forging blank.

[0087] 7) After forging, the obtained high-temperature alloy forging billet is air-cooled to a surface temperature below 100°C;

[0088] 8) After cooling, the forging billet is machined and polished until the surface is free of cracks;

[0089] 9) Place the polished high-temperature alloy forging billet in a heat treatment furnace at 1010℃ and hold for 4 hours. After holding, perform radial forging on the high-temperature alloy forging billet. The radial forging includes four passes, with the forging frequency of each pass controlled at 60~240 times / min. The total deformation is 41%, and the forging billet is forged into a forging bar with a diameter of φ400mm.

[0090] After the pre-deformation in step 4), the large-sized Laves phase in the high-temperature alloy ingot is broken down and reduced in size, which reduces the degree of ingot segregation and the difficulty of material homogenization.

[0091] After homogenization heat treatment at 1140℃ / 16h + 1190℃ / 72h in step 5), the segregation elements in the high-temperature alloy diffused uniformly, and the residual segregation coefficients were reduced to below 0.2.

[0092] After step 9) radial forging, the φ400mm high-temperature alloy forged bar has a grain size of 6.5~7.5 from the center to the edge, with a range of 1, and a uniform microstructure. Figure 1 As shown, the tensile strength at room temperature is 1386 MPa.

[0093] Comparative Example 1

[0094] 1) The Φ660mm high-temperature alloy ingot prepared by vacuum induction-electroslag remelting-vacuum self-consumption has the following chemical composition (wt%): Cr: 18.5, Fe: 18.5, Mo: 3.0, Nb: 5.2, with the remainder being Ni and small amounts of Co, Mn, Al, Si, Ti, etc.

[0095] 2) Based on the composition and tests of the high-temperature alloy, its hot deformation temperature range is 1000℃~1100℃, the critical deformation amount for cracking is 60%, the highest safe remelting temperature of the precipitated phase is 1150℃, and the equilibrium solid-liquid phase temperature of the high-temperature alloy is 1216℃.

[0096] 3) Place the high-temperature alloy ingot in a heat treatment furnace at 700℃, raise the temperature to 1130℃ at a heating rate of 50℃ / h, and hold for 24h; continue raising the temperature to 1160℃ at a heating rate of 50℃ / h, and hold for 24h; continue raising the temperature to 1190℃ at a heating rate of 50℃ / h, and hold for 108h; after holding, cool the furnace to below 700℃, and remove and air cool.

[0097] 4) The homogenized high-temperature alloy ingot is subjected to four upsetting and four drawing hot deformation in seven heat treatments: Before each upsetting or drawing, the ingot is wrapped with heat insulation cotton and kept in a heat treatment furnace at 1020℃~1100℃ for 2~4 hours. After the hot deformation, the high-temperature alloy ingot is forged into a 520mm octagonal forging blank.

[0098] 5) After forging, the high-temperature alloy forging billet is air-cooled to a surface temperature below 100°C;

[0099] 6) After cooling, the forging billet is machined and polished until the surface is free of cracks;

[0100] 7) Place the polished high-temperature alloy forging billet in a heat treatment furnace at 1010℃ and hold for 4 hours. After holding, perform radial forging on the high-temperature alloy forging billet. The radial forging includes four passes, and the forging frequency of each pass is controlled at 60~240 times / min. Forge the billet into a forging bar with a diameter of φ400mm.

[0101] After the homogenization heat treatment of step 3) at 1130℃ / 24h + 1160℃ / 24h + 1190℃ / 108h, the segregation elements in the high-temperature alloy diffused uniformly, and the residual segregation coefficients were reduced to below 0.2.

[0102] After step 7) radial forging, the φ400mm high-temperature alloy forged bar has a grain size of grade 6-7 from the center to the edge, with a range of grade 1, and a uniform microstructure. Figure 2 As shown, the tensile strength at room temperature is 1349 MPa.

[0103] Comparative Example 2 CN119411047A discloses a method for preparing a Φ400mm rod:

[0104] 1) A Φ508mm electroslag ingot was obtained by dual smelting of vacuum induction and electroslag remelting. The chemical composition (wt%) included: Ni 54.61, Nb 5.09, Ti 0.87, Al 0.39, Mo 2.92, C 0.042, Cr 18.88, Fe balance;

[0105] 2) The electroslag ingot is subjected to homogenization heat treatment. The electroslag ingot is held at 740℃ for 8 hours, then heated to 1160℃ at a rate of 70℃ / h and held for 25 hours. Then it is heated to 1189℃ at a rate of 70℃ / h and held for 110 hours. Then it is cooled to 1085℃ at a rate of 50℃ / h and held for 4 hours. Finally, it is taken out of the furnace and air-cooled.

[0106] 3) The electroslag ingot after homogenization heat treatment is heated before forging, and then subjected to two drawing and two upsetting processes to obtain semi-finished bar stock;

[0107] 4) Continuously draw the semi-finished bar stock to the finished forging specification of Φ400mm.

[0108] The GH4169 Φ400mm bar obtained in this comparative example has a grain size of 6.5~7.5 from the edge to the center, with a grade difference of 1, and the grains are uniform.

[0109] The preparation methods of the above embodiments and comparative examples are different, but they can all make the segregated elements in the original ingot diffuse evenly, and prepare large-sized deformed high-temperature alloy forging bars with uniform structure. In addition, the materials in the embodiments have higher room temperature tensile strength, and the forging bar preparation time in the embodiments is shorter, which reduces production energy consumption, reduces material oxidation, and increases the yield of finished products.

[0110] Example 2

[0111] 1) The Φ660mm high-temperature alloy ingot prepared by vacuum induction-electroslag remelting-vacuum self-consumption has the following chemical composition (wt%): Cr: 18.5, Fe: 18.5, Mo: 3.0, Nb: 5.2, with the remainder being Ni and small amounts of Co, Mn, Al, Si, Ti, etc.

[0112] 2) Based on the composition and tests of the above high-temperature alloy, its hot deformation temperature range is 1000℃~1100℃, the critical deformation amount for cracking is 60%, the highest safe remelting temperature of the precipitated phase is 1150℃, and the equilibrium solid-liquid phase temperature of the high-temperature alloy is 1216℃.

[0113] 3) Hold the high-temperature alloy ingot obtained in step 1) at 1100℃ for 3 hours, then wrap the ingot with insulation cotton and continue to hold it in the furnace for 2 hours.

[0114] 4) Upset the high-temperature alloy ingot, with a deformation of 25%. After upsetting, re-wrap it with insulation cotton, and then heat it in the furnace at 1100℃ for 1.5 hours. After heat treatment, draw it out, with a deformation of 25%.

[0115] 5) The high-temperature alloy ingot after the pre-deformation is subjected to homogenization heat treatment: the pre-deformed high-temperature alloy ingot is placed in a heat treatment furnace at 1100℃, heated to 1130℃ at a heating rate of 50℃ / h, and held for 24h; then heated to 1190℃ at a heating rate of 50℃ / h and held for 60h; after holding, the furnace is cooled to below 700℃ and then air-cooled.

[0116] 6) The homogenized high-temperature alloy ingot is subjected to four upsetting and four drawing hot deformation in seven heat treatments: Before each upsetting or drawing, the ingot is wrapped with heat insulation cotton and kept in a heat treatment furnace at 1020℃~1100℃ for 2~4 hours. After the hot deformation, the high-temperature alloy ingot is forged into a 520mm octagonal forging blank.

[0117] 7) After forging, the obtained high-temperature alloy forging billet is air-cooled to a surface temperature below 100°C;

[0118] 8) After cooling, the forging billet is machined and polished until the surface is free of cracks;

[0119] 9) Place the polished high-temperature alloy forging billet in a heat treatment furnace at 1010℃ and hold for 4 hours. After holding, perform radial forging on the high-temperature alloy forging billet. The radial forging includes four passes, with the forging frequency of each pass controlled at 60~240 times / min. The total deformation is 47%, and the forging billet is forged into a forging bar with a diameter of φ380mm.

[0120] After the pre-deformation in step 4), the large-sized Laves phase in the high-temperature alloy ingot is broken down and reduced in size, which reduces the degree of ingot segregation and the difficulty of material homogenization.

[0121] After the homogenization heat treatment of 1130℃ / 24h+1190℃ / 60h in step 5), the segregation elements in the high-temperature alloy diffused uniformly, and the residual segregation coefficients were reduced to below 0.2.

[0122] After step 9) radial forging, the φ380mm high-temperature alloy forged bar has a grain size of 6.5~7.5 from the center to the edge, with a range of 1, and a uniform microstructure. Figure 3 As shown; the tensile strength at room temperature is 1415 MPa.

[0123] Example 3

[0124] 1) The Φ660mm high-temperature alloy ingot prepared by vacuum induction-electroslag remelting-vacuum self-consumption has the following chemical composition (wt%): Cr: 18.5, Fe: 18.5, Mo: 3.0, Nb: 5.2, with the remainder being Ni and small amounts of Co, Mn, Al, Si, Ti, etc.

[0125] 2) Based on the composition and tests of the above high-temperature alloy, its hot deformation temperature range is 1000℃~1100℃, the critical deformation amount for cracking is 60%, the highest safe remelting temperature of the precipitated phase is 1150℃, and the equilibrium solid-liquid phase temperature of the high-temperature alloy is 1216℃.

[0126] 3) Hold the high-temperature alloy ingot obtained in step 1) at 1100℃ for 3 hours, wrap the ingot with insulation cotton, and continue to hold it in the furnace for 2 hours.

[0127] 4) Upset the high-temperature alloy ingot, with a deformation of 25%. After upsetting, re-wrap it with insulation cotton, and then heat it in the furnace at 1100℃ for 1.5 hours. After heat treatment, draw it out, with a deformation of 25%.

[0128] 5) The high-temperature alloy ingot after the pre-deformation is subjected to homogenization heat treatment: the pre-deformed high-temperature alloy ingot is placed in a heat treatment furnace at 1100℃, heated to 1130℃ at a heating rate of 50℃ / h, and held for 24h; then heated to 1190℃ at a heating rate of 50℃ / h and held for 60h; after holding, the furnace is cooled to below 700℃ and then air-cooled.

[0129] 6) The homogenized high-temperature alloy ingot is subjected to four upsetting and four drawing hot deformation in seven heat treatments: Before each upsetting or drawing, the ingot is wrapped with heat insulation cotton and kept in a heat treatment furnace at 1020℃~1100℃ for 2~4 hours. After the hot deformation, the high-temperature alloy ingot is forged into a 520mm octagonal forging blank.

[0130] 7) After forging, the obtained high-temperature alloy forging billet is air-cooled to a surface temperature below 100°C;

[0131] 8) After cooling, the forging billet is machined and polished until the surface is free of cracks;

[0132] 9) Place the polished high-temperature alloy forging billet in a heat treatment furnace at 1010℃ and hold for 4 hours. After holding, perform radial forging on the high-temperature alloy forging billet. The radial forging includes four passes, with the forging frequency of each pass controlled at 60~240 times / min and the total deformation amount being 55%. Forge the billet into a forging bar with a diameter of φ350mm.

[0133] After the pre-deformation in step 4), the large-sized Laves phase in the high-temperature alloy ingot is broken down and reduced in size, which reduces the degree of ingot segregation and the difficulty of material homogenization.

[0134] After the homogenization heat treatment of 1130℃ / 24h+1190℃ / 60h in step 5), the segregation elements in the high-temperature alloy diffused uniformly, and the residual segregation coefficients were reduced to below 0.2.

[0135] After step 9) radial forging, the φ350mm high-temperature alloy forged bar has a grain size of 7~7.5 from the center to the edge, with a range of 0.5, and a uniform microstructure. Figure 4 As shown, the tensile strength at room temperature is 1389 MPa.

[0136] Comparative Example 3

[0137] 1) The Φ660mm high-temperature alloy ingot prepared by vacuum induction-electroslag remelting-vacuum self-consumption has the following chemical composition (wt%): Cr: 18.5, Fe: 18.5, Mo: 3.0, Nb: 5.2, with the remainder being Ni and small amounts of Co, Mn, Al, Si, Ti, etc.

[0138] 2) Based on the composition and tests of the above high-temperature alloy, its hot deformation temperature range is 1000℃~1100℃, the critical deformation amount for cracking is 60%, the highest safe remelting temperature of the precipitated phase is 1150℃, and the equilibrium solid-liquid phase temperature of the high-temperature alloy is 1216℃.

[0139] 3) Hold the high-temperature alloy ingot obtained in step 1) at 1100℃ for 3 hours, then wrap the ingot with insulation cotton and continue to hold it in the furnace for 2 hours.

[0140] 4) Upsetting the high-temperature alloy ingot with a deformation of 45%, re-wrapping it with insulation cotton after upsetting, and then holding it in the furnace at 1100℃ for 1.5 hours. After holding, drawing is performed with a deformation of 25%.

[0141] 5) The high-temperature alloy ingot after the pre-deformation is subjected to homogenization heat treatment: the pre-deformed high-temperature alloy ingot is placed in a heat treatment furnace at 1100℃, heated to 1140℃ at a heating rate of 50℃ / h, and held for 16h; then heated to 1190℃ at a heating rate of 50℃ / h and held for 30h; after holding, the furnace is cooled to below 700℃ and then air-cooled.

[0142] 6) The homogenized high-temperature alloy ingot is subjected to four upsetting and four drawing hot deformation processes in seven heat treatments. Before each upsetting or drawing, the ingot is wrapped with heat-insulating cotton and kept in a heat treatment furnace at 1020℃~1100℃ for 2~4 hours.

[0143] After the pre-deformation in step 4), the large-sized Laves phase in the high-temperature alloy ingot is broken down and reduced in size, which reduces the degree of ingot segregation and the difficulty of material homogenization.

[0144] However, the homogenization time of 1140℃ / 16h + 1190℃ / 30h in step 5) was too short, and the segregated elements in the high-temperature alloy were not completely diffused uniformly. The residual segregation coefficient of Nb element was greater than 0.35. As a result, the high-temperature alloy ingot cracked and the forging failed during the hot deformation of the billet in step 6).

[0145] Example 4

[0146] 1) A Φ660mm high-temperature alloy ingot prepared by vacuum induction-electroslag remelting-vacuum self-consumption has the following chemical composition (wt%): Co: 13.5, Cr: 19.5, Mo: 4.25, Ti: 3, with the remainder being Ni and small amounts of Al, Fe, Mn, Si, etc.

[0147] 2) Based on the composition and tests of the above high-temperature alloy, its hot deformation temperature range is 1040℃~1170℃, the critical deformation amount for cracking is 60%, the highest safe remelting temperature of the precipitated phase is 1305℃, and the equilibrium solid-liquid phase temperature of the high-temperature alloy is 1266℃.

[0148] 3) Hold the high-temperature alloy ingot obtained in step 1) at 1160℃ for 3 hours;

[0149] 4) Upsetting the high-temperature alloy ingot with a deformation of 25%, followed by furnace heating at 1160℃ for 1.5 hours, and then drawing with a deformation of 25%.

[0150] 5) The high-temperature alloy ingot after the above pre-deformation is subjected to homogenization heat treatment: the pre-deformed high-temperature alloy ingot is placed in a heat treatment furnace at a temperature of 1160℃, heated to 1240℃ at a heating rate of 50℃ / h, and held for 30h; after the holding is completed, the furnace is cooled to below 700℃ and then air-cooled.

[0151] 6) Perform four upsetting and four drawing hot deformations on the homogenized high-temperature alloy ingots in seven heat treatments: Before each upsetting or drawing, hold the ingots at 1040℃~1160℃ for 2~4 hours. After the hot deformation, forge the high-temperature alloy ingots into 520mm octagonal billets.

[0152] 7) After forging, the obtained high-temperature alloy forging billet is air-cooled to a surface temperature below 100°C;

[0153] 8) After cooling, the forging billet is machined and polished until the surface is free of cracks;

[0154] 9) Place the polished high-temperature alloy forging billet in a heat treatment furnace at 1020℃ and hold for 4 hours. After holding, perform radial forging on the high-temperature alloy forging billet. The radial forging includes four passes, with the forging frequency of each pass controlled at 60~240 times / min. The total deformation is 47%, and the forging billet is forged into a forging bar with a diameter of φ380mm.

[0155] After the pre-deformation in step 4), the large-sized carbide phases in the high-temperature alloy ingot are broken down and reduced in size, which reduces the degree of segregation in the ingot and reduces the difficulty of material homogenization.

[0156] After the homogenization heat treatment at 1240℃ for 36h in step 5), the segregation elements in the high-temperature alloy diffused uniformly, and the residual segregation coefficients were reduced to below 0.2.

[0157] After step 9), the φ380mm high-temperature alloy forged bar has a grain size of 4.5~5 from the center to the edge, with a range of 0.5, and a uniform microstructure. The tensile strength at room temperature is 1326MPa.

[0158] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0159] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing ultra-large ingot-shaped high-temperature alloy forgings, comprising the following steps: S1. Heating the high-temperature alloy ingot; S2. Pre-deform the high-temperature alloy ingot obtained in step S1, wherein the pre-deformation includes upsetting and drawing in sequence. When T 1max -T 1min At temperatures above 100℃, the upsetting deformation ε0 is 1 / 3ε c ~2 / 3ε c The elongation deformation ε0' is 1 / 3ε c ~2 / 3ε c When the surface temperature of the ingot decreases to (T 1min Before pre-deformation is completed at +20℃, the furnace is reheated for 1-2 hours. When T 1max -T 1min At ≤100℃, the upsetting deformation ε0 is 1 / 3ε c ~1 / 2ε c The elongation deformation ε0' is 1 / 3ε c ~1 / 2ε c After the upsetting process is completed, the surface of the upset ingot is wrapped with insulating cotton and then returned to the furnace for insulation. S3. The pre-deformed high-temperature alloy ingot is subjected to homogenization heat treatment. For T p <T s The high-temperature alloy, wherein the homogenization heat treatment specifically comprises: The high-temperature alloy ingot is placed in a heat treatment furnace of T1 and heated to T. h1 Hold at temperature t1, then raise the temperature to T. h2 Keep warm and then cool; For T p ≥T s The high-temperature alloy, wherein the homogenization heat treatment specifically comprises: The high-temperature alloy ingot is placed in a heat treatment furnace of T1 and heated to T. h2 Keep warm and then cool; S4. The high-temperature alloy ingot after homogenization heat treatment is subjected to billet hot deformation, with a total deformation of 1 / 3ε. c ~3 / 4ε c ; S5. After cooling the forging billet obtained in step S4, perform heat treatment and finally radial forging. The heat distortion temperature range is T. 1min ~T 1max Critical deformation ε for cracking c Maximum safe remelting temperature of precipitated phase T P Equilibrium solid-liquid phase temperature T s ; T 1min ≤T1≤T 1max T h1 The range of values ​​for is (T) p -50℃)~(T p -10℃), t1=Aexp(-0.0186T h1 The value of A is in the range of 1.5 * 10^6. 10 ~5*10 10 ; T h2 The range of values ​​for is (T) s -100℃)~(T s -10℃).

2. The preparation method according to claim 1, characterized in that, In step S1, the heating specifically involves: When T 1max -T 1min >100℃, place the high-temperature alloy ingot in the T1 heat treatment furnace and hold for 3~5 hours; When T 1max -T 1min At ≤100℃, place the high-temperature alloy ingot in a T1 heat treatment furnace and hold it for 3~5 hours. After holding, wrap the ingot with insulation cotton and continue to hold it in a T1 heat treatment furnace for 1~2 hours.

3. The preparation method according to claim 1, characterized in that, In step S3, for T p <T s High-temperature alloys, T1 heated to T h1 The heating rate is 50~100℃ / h, T h1 Heat up to T h2 The heating rate is 20~100℃ / h; and / or, the temperature is increased to T. h2 The heat preservation time is 36~90 hours.

4. The preparation method according to claim 1, characterized in that, In step S3, for T p ≥T s High-temperature alloys, T1 heated to T h2 The heating rate is 20~100℃ / h; and / or, the temperature is increased to T. h2 The heat preservation time is 24~72h.

5. The preparation method according to claim 1, characterized in that, In step S3, the cooling method is specifically: furnace cooling to below 700°C followed by air cooling.

6. The preparation method according to claim 1, characterized in that, In step S4, the hot deformation method of the billet is four upsetting and four drawing processes with seven heating cycles. The heating temperature before each upsetting and each drawing is T. 1min ~T1, keep warm for 2~4 hours.

7. The preparation method according to claim 1, characterized in that, In step S5, the cooling specifically involves air cooling to below 100°C on the surface of the high-temperature alloy ingot; and / or, the heat treatment temperature is T2, and the holding time is 3-5 hours, wherein T2 ≥ T1 - 200°C; and / or, the radial forging includes multiple passes, with the forging frequency of each pass controlled at 60-240 times / min, and the total deformation controlled at 1 / 3ε. c ~3 / 4ε c .

8. The preparation method according to any one of claims 1 to 7, characterized in that, The diameter of the high-temperature alloy ingot is >600mm, and the diameter of the high-temperature alloy forging is ≥350mm; And / or, the high-temperature alloy ingot includes GH4169, GH2909 or GH738.

9. The high-temperature alloy forging prepared by the preparation method according to any one of claims 1 to 8.

10. The high-temperature alloy forging according to claim 9, characterized in that, The grain size from the edge to the center of the high-temperature alloy forging is grade 4.5~5, grade 6.5~7.5, and grade 7~7.5, with grade differences of 0.5, 1, and 0.5, respectively.

Images