A method for preparing GH4145 alloy foil

Abstract

The present invention belongs to the technical field of nickel-based high-temperature alloy foil preparation, and discloses a method for preparing GH4145 alloy foil. It includes: vacuum induction melting, ingot forging, hot rolling, solution treatment, multiple passes of four-roll cold rolling + stress relief annealing, pickling + trimming, multiple passes of twenty-roll cold rolling + stress relief annealing, and finished product annealing. The ingot forging temperature is 1020℃-1050℃; the hot rolling temperature is 1050℃-1085℃; the solution treatment is kept at 1085℃ for 60 minutes; the cold rolling deformation is controlled to be less than 50%; and stress relief annealing is performed between passes. The alloy foil obtained by the preparation method of the present invention has the advantages of low stress, excellent mechanical properties, high dimensional accuracy and smooth surface, and can meet the use requirements in aerospace, chip preparation, nuclear reactors and new energy batteries.

Description

Technical Field

[0001] The invention relates to the technical field of nickel-based high-temperature alloy foil preparation, and in particular to a method for preparing a GH4145 alloy foil. Background Art

[0002] GH4145 alloy is a nickel-based face-centered cubic high-temperature alloy with γ´ as the main strengthening phase. It has excellent high temperature resistance, corrosion resistance and oxidation resistance at 900℃-1200℃ and is widely used in aviation aircraft, rocket engines, chip preparation, nuclear reactors and new energy batteries. There is a huge demand for GH4145 alloy foil with a thickness of less than 0.1mm in China, but it is still heavily dependent on foreign imports due to the limitations of preparation technology. A complete domestic preparation process technology is urgently needed.

[0003] For the GH4145 alloy foil preparation technology, there are mainly the following main problems:

[0004] (1) The alloy has high stress and is difficult to process:

[0005] GH4145 alloy contains more strengthening elements such as Cr, Al, Ti, Nb, etc. The temperature range of hot working is small. Strengthening phases and carbides are easily precipitated during heat treatment, which causes the plasticity and toughness of the alloy to decrease. The internal stress is extremely large during cold and hot processing, and it is difficult to thin it to less than 0.1mm.

[0006] (2) The alloy foil preparation process is not systematic and the yield rate is low:

[0007] The preparation technology of nickel-based high-temperature alloy foil is affected by many factors such as raw materials, processing equipment, and process flow. The preparation technology of GH4145 alloy foil has not been studied in China, so it is necessary to conduct in-depth and systematic research on forging process, cold rolling and hot rolling parameters, solution system, and stress relief annealing system. Reasonable deformation and stress relief annealing process can completely recrystallize the structure and prevent stress concentration and strip deformation and cracking caused by excessive deformation.

[0008] (3) Alloy foil cannot meet the requirements of high-tech fields and has poor performance:

[0009] Precision manufacturing has strict requirements for nickel-based high-temperature alloy foil, requiring low stress, high dimensional accuracy and surface quality. Since the GH4145 alloy has high deformation resistance and high processing difficulty, even if the foil can be formed and prepared, it is difficult to meet the specified dimensional accuracy and forming performance. The present invention can solve this pain point problem through reasonable rolling and heat treatment processes, and provide a systematic preparation technology with simple process and low cost for the application of GH4145 alloy foil. Summary of the invention

[0010] The purpose of the present invention is to provide a method for preparing GH4145 alloy foil, and to obtain a low-stress alloy foil with uniform structure and excellent mechanical properties through a reasonable cold rolling process and stress relief annealing process, so as to meet the use requirements in the fields of aerospace, chip preparation, nuclear reactors and new energy batteries, and provide a systematic preparation method for the domestic production of GH4145 alloy foil.

[0011] The technical solution of the present invention is as follows:

[0012] Low stress GH4145 alloy foil is prepared through reasonable deformation and heat treatment process. The process flow is: vacuum induction melting, ingot forging, hot rolling, solution treatment, multi-pass four-roll cold rolling + stress relief annealing, pickling + trimming, multi-pass twenty-roll cold rolling + stress relief annealing, and finished product annealing.

[0013] The specific process is as follows:

[0014] Step (1), vacuum induction melting: melting GH4145 alloy ingots by vacuum induction plus electroslag remelting;

[0015] Step (2), ingot forging: forging the GH4145 alloy ingot into a 30-40 mm thick slab, with the overall deformation controlled at 55%-70%;

[0016] Step (3), hot rolling: hot rolling the GH4145 alloy slab into a strip at a temperature of 1050°C-1085°C, and air cooling;

[0017] Step (4), solution treatment: subjecting the 2-3 mm thick hot-rolled strip to solution treatment at a temperature of 1085°C for 60 minutes and water cooling;

[0018] Step (5), multi-pass four-roller cold rolling + stress relief annealing: a four-roller rolling mill performs multi-pass room temperature rolling to obtain a thin strip with a thickness of 0.2-0.25 mm; stress relief annealing is performed between passes, the stress relief annealing temperature is 1020°C-1035°C, the holding time is 15-30 minutes, and water cooling is performed; the stress relief annealing adopts 99.99% argon vacuum annealing, and argon is continuously introduced for furnace cooling; when the strip thickness is 0.3-0.4 mm, pickling is performed to remove surface oxides and impurities, and edge trimming is performed;

[0019] The rolling speed is maintained at 0.03-0.06 m / s, and the deformation per pass is less than 50% to reduce stress concentration;

[0020] Step (6), multi-pass twenty-roller cold rolling + stress relief annealing: the twenty-roller rolling mill is rolled at room temperature to obtain a foil with a thickness of 0.05-0.1 mm; the stress relief annealing temperature between passes is 960°C-990°C, and the temperature is kept for 30-45 minutes;

[0021] Step (7), annealing the finished product;

[0022] Furthermore, in the ingot forging, the temperature of the ingot forged into a slab is 1020°C-1050°C.

[0023] Furthermore, the slab in the hot rolling process needs to be hot rolled into a 2-3 mm thick strip with a deformation of 90%-95%.

[0024] Furthermore, water cooling is performed after the solution treatment to reduce the generation of carbides and precipitation phases, thereby reducing stress.

[0025] The purpose of trimming is to remove cracks at the edges after cold rolling, ensure uniform thickness of the strip, and prevent stress concentration and deformation cracking during subsequent cold rolling.

[0026] In the multi-pass twenty-roller cold rolling process, the rolling speed is maintained at 0.01-0.03 m / s, and the deformation in each pass is less than 50%, minimizing stress.

[0027] The finished product annealing is argon protected vacuum annealing at a temperature of 980°C for 45 minutes.

[0028] The final finished foil has a thickness of 0.05-0.1mm and a KAM value of ≤0.1°, indicating that it has extremely low stress and an elongation of 13-22%.

[0029] There are a large number of evenly distributed and deep dimples on the tensile fracture of the finished foil of target thickness, which is an obvious ductile fracture, indicating that its plastic toughness is good.

[0030] The beneficial effects of the present invention are:

[0031] The present invention provides a systematic stress reduction process method in the technical field of domestic production of GH4145 alloy foil. By controlling the rolling speed and the deformation between passes by a multi-roll cold rolling mill and cooperating with a stress relief annealing process, a high-precision low-stress foil with a thickness of 0.05-0.1mm is obtained, and the error is within ±0.003. The current situation of uneven deformation and deformation cracking caused by excessive stress during the cold rolling of difficult-to-deform alloys has been greatly improved. A GH4145 alloy foil with low stress, excellent mechanical properties, high dimensional accuracy and smooth surface is obtained. In addition, the foil preparation process described in the present invention has the advantages of simple process, high yield rate and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the microstructure of the plate after solid solution.

[0033] Figure 2 The microstructure of the finished foil with a thickness of 0.052mm.

[0034] Figure 3 The microstructure of the finished foil with a thickness of 0.095 mm.

[0035] Figure 4 This is the KAM diagram of 0.052mm thick foil after stress relief annealing.

[0036] Figure 5 This is the KAM diagram of 0.095mm thick foil after stress relief annealing.

[0037] Figure 6 Mechanical properties of finished foil with thickness of 0.052mm.

[0038] Figure 7 Mechanical properties of finished foil with thickness of 0.095mm.

[0039] Figure 8 This is the tensile fracture structure of the finished foil with a thickness of 0.075mm. DETAILED DESCRIPTION

[0040] The chemical composition and content of the materials involved in the preparation method of the GH4145 alloy foil of the present invention are shown in Table 1.

[0041] Table 1 Chemical composition and content of each component of GH4145 alloy

[0042]

[0043] The preparation process of the present invention is described in detail below in conjunction with specific embodiments.

[0044] Example 1

[0045] The GH4145 alloy ingot was melted by vacuum induction, and then forged into a 40 mm thick slab at 1020℃-1050℃, with an overall deformation of about 55%. The slab was hot rolled into a 3 mm thick strip at 1080℃, air cooled, and the deformation was about 92.5%. The solution treatment temperature was 1085℃, kept for 60 minutes, and water cooled. Subsequently, multiple cold rolling and stress relief annealing were carried out, and pickling and trimming were carried out at a thickness of about 0.34mm, and finally a foil with a thickness of 0.058mm was obtained. The rolling process parameters are shown in Table 2.

[0046] Table 2 Rolling process parameters involved in Example 1

[0047]

[0048] Example 2

[0049] GH4145 alloy ingots were melted by vacuum induction, and then forged into 35mm thick slabs at 1020℃-1050℃, with an overall deformation of about 60%. The slabs were hot rolled into 2mm thick strips at 1060℃, air-cooled, and the deformation was about 94%. The solution treatment temperature was 1085℃, kept for 60 minutes, and water-cooled. The microstructure after solution treatment Figure 1 As shown. Then, multiple cold rolling and stress relief annealing are carried out, and pickling and trimming are carried out when the thickness is about 0.37mm, and finally a foil with a thickness of 0.052mm is obtained. Figure 2 The KAM value of the foil after stress relief annealing is 0.07°, indicating that the internal stress of the foil is extremely low. Figure 4 This is the KAM diagram of the foil after stress relief annealing. Figure 6 The rolling process parameters are shown in Table 3.

[0050] Table 3 Rolling process parameters involved in Example 2

[0051]

[0052] Example 3

[0053] GH4145 alloy ingots were melted by vacuum induction, and then forged into 30mm thick slabs at 1020℃-1050℃, with an overall deformation of about 70%. The slabs were hot rolled into 2.6mm thick strips at 1050℃, air-cooled, and the deformation was about 91.3%. The solution treatment temperature was 1085℃, kept for 60 minutes, and water-cooled. Subsequently, multiple cold rolling and stress relief annealing were carried out, and pickling and trimming were carried out at a thickness of about 0.40mm. Finally, a foil with a thickness of 0.095mm was obtained. Figure 3 The KAM value of the foil after stress relief annealing is 0.09°, indicating that the internal stress of the foil is extremely low. Figure 5 This is the KAM diagram of the foil after stress relief annealing. Figure 7 The rolling process parameters are shown in Table 4.

[0054] Table 4 Rolling process parameters involved in Example 3

[0055]

[0056] Example 4

[0057] The GH4145 alloy ingots were melted by vacuum induction melting, and then forged into 40mm thick slabs at 1020℃-1050℃, with an overall deformation of about 55%. The slabs were hot rolled into 2.5mm thick strips at 1070℃, air-cooled, and the deformation was about 93.8%. The solution treatment temperature was 1085℃, kept for 60 minutes, and water-cooled. Subsequently, multiple cold rolling and stress relief annealing were carried out, and pickling and trimming were carried out when the thickness was about 0.38mm. Finally, a foil with a thickness of 0.075mm was obtained. There were a large number of evenly distributed and deep dimples on the tensile fracture of the foil, which was an obvious ductile fracture, indicating that it had good plastic toughness. Figure 8 The tensile fracture structure of the foil is shown in Table 5.

[0058] Table 5 Rolling process parameters involved in Example 4

[0059]

[0060] Example 5

[0061] The GH4145 alloy ingot was melted by vacuum induction, and then forged into a 40 mm thick slab at 1020℃-1050℃, with an overall deformation of about 55%. The slab was hot rolled into a 2.4 mm thick strip at 1080℃, air-cooled, and the deformation was about 94%. The solution treatment temperature was 1085℃, kept for 60 minutes, and water-cooled. Subsequently, multiple cold rolling and stress relief annealing were carried out, and pickling and trimming were carried out at a thickness of about 0.35 mm, and finally a foil with a thickness of 0.063 mm was obtained. The rolling process parameters are shown in Table 6.

[0062] Table 6 Rolling process parameters involved in Example 5

[0063]

[0064] Comparative Example 1

[0065] The GH4145 alloy ingot was melted by vacuum induction, and then forged into a 35mm thick slab at 1020℃-1050℃, with an overall deformation of about 60%. The slab was hot rolled into a 2mm thick strip at 1060℃, air-cooled, and the deformation was about 94%. The solution treatment temperature was 1085℃, kept for 60 minutes, and water-cooled. Subsequently, multiple cold rolling and stress relief annealing were carried out, and pickling and trimming were carried out when the thickness was about 0.32mm. The expected target thickness was 0.05-0.06mm, but due to the high rolling speed and high stress, deformation and cracking occurred at 0.089mm. After annealing again, the edge sawtooth cracking occurred when it was rolled to 0.077mm, and it was impossible to continue thinning. The rolling process parameters are shown in Table 7.

[0066] Table 7 Rolling process parameters involved in Comparative Example 1

[0067]

[0068] Comparative Example 2

[0069] The GH4145 alloy ingot was melted by vacuum induction, and then forged into a 35mm thick slab at 1020℃-1050℃, with an overall deformation of about 60%. The slab was hot rolled into a 2.8mm thick strip at 1080℃, air-cooled, and the deformation was about 92%. The solution treatment temperature was 1085℃, kept warm for 60 minutes, and water-cooled. Subsequently, multiple cold rolling and stress relief annealing were carried out, and pickling and trimming were carried out when the thickness was about 0.39mm. The expected target thickness was 0.05-0.06mm, but due to the slow rolling speed, when the foil was cold rolled to 0.091mm thick, irregular indentations and wrinkles appeared on the surface of the foil, the thickness was extremely uneven, and the local stress was too large, resulting in serrated cracks at the edge. After annealing again, it was rolled to 0.082mm and tore, and it could not be further thinned. The slow rolling speed also led to large mechanical losses and high costs. The rolling process parameters are shown in Table 8.

[0070] Table 8 Rolling process parameters involved in Comparative Example 2

[0071]

[0072] Comparative Example 3

[0073] The GH4145 alloy ingot was melted by vacuum induction melting, and then forged into a 35mm thick slab at 1020℃-1050℃, with an overall deformation of about 60%. The slab was hot rolled into a 3mm thick strip at 1020℃, air-cooled, and the deformation was about 91.4%. The solution treatment temperature was 1020℃, kept warm for 45 minutes, and water-cooled. Subsequently, multiple cold rolling and stress relief annealing were carried out, and pickling and trimming were carried out when the thickness was about 0.31mm. The expected target thickness was 0.06-0.07mm, but due to the unreasonable stress relief annealing process, the stress of the material was large, and the edge serrated cracking occurred at 0.094mm. After annealing again, the strip broke when it was rolled to 0.086mm, and it was impossible to continue thinning. The rolling process parameters are shown in Table 9.

[0074] Table 9 Rolling process parameters involved in Comparative Example 3

[0075]

[0076] Comparative Example 4

[0077] The GH4145 alloy ingot was melted by vacuum induction, and then forged into a 40mm thick slab at 1020℃-1050℃, with an overall deformation of about 55%. The slab was hot rolled into a 2.5mm thick strip at 1150℃, air-cooled, and the deformation was about 93.8%. The solution treatment temperature was 1120℃, kept warm for 45 minutes, and water-cooled. Subsequently, multiple cold rolling and stress relief annealing were carried out, and pickling and trimming were carried out when the thickness was about 0.38mm. The expected target thickness was 0.06-0.07mm, but due to the unreasonable stress relief annealing process, the grains grew abnormally, the stress of the material was large, and severe cracking occurred at 0.09mm. After annealing again, the strip broke when it was rolled to 0.079mm, and it was impossible to continue thinning. The rolling process parameters are shown in Table 10.

[0078] Table 10 Rolling process parameters involved in Comparative Example 4

[0079]

[0080] The mechanical properties of the finished GH4145 alloy foil are shown in Table 11.

[0081] Table 11 Mechanical properties and stress magnitude of GH4145 alloy foil finished products

[0082]

[0083] The parts not described in detail in the present invention are known technologies.

[0084] The above specific implementations are only used to illustrate the technical solutions and features of the present invention, mainly to allow people familiar with the technology to quickly understand the content of the present invention and implement it accordingly, but they cannot be used to limit the scope of protection of the present invention. All equivalent modifications or replacements made according to the technical solution of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing GH4145 alloy foil, characterized in that: The steps include: Step 1, vacuum induction melting: melting GH4145 alloy ingot by vacuum induction plus electroslag remelting; Step 2, ingot forging: forging the GH4145 alloy ingot into a 30-40 mm thick slab, with the overall deformation controlled at 55%-70%; Step 3, hot rolling: hot rolling the GH4145 alloy slab into a strip at a temperature of 1050°C-1085°C, and air cooling; Step 4, solution treatment: subject the 2-3 mm thick hot-rolled strip to solution treatment at a temperature of 1085°C for 60 minutes and water cooling; Step 5, multi-pass four-roller cold rolling + stress relief annealing: a four-roller rolling mill performs multi-pass room temperature rolling to obtain a thin strip with a thickness of 0.2-0.25 mm; stress relief annealing is performed between passes, the stress relief annealing temperature is 1020°C-1035°C, the holding time is 15-30 minutes, and water cooling is performed; the stress relief annealing adopts 99.99% argon vacuum annealing, and argon is continuously introduced for furnace cooling; when the strip thickness is 0.3-0.4 mm, pickling is performed to remove surface oxides and impurities, and edge trimming is performed; The rolling speed is maintained at 0.03-0.06 m / s, and the deformation per pass is less than 50% to reduce stress concentration; Step 6, multi-pass twenty-roller cold rolling + stress relief annealing: The twenty-roller rolling mill is rolled at room temperature to obtain a foil with a thickness of 0.05-0.1 mm; the stress relief annealing temperature between passes is 960°C-990°C, and the temperature is kept for 30-45 minutes; the rolling speed is maintained at 0.01-0.03 m / s, and the deformation of each pass is less than 50%; Step 7, annealing of finished product; The final finished foil has a thickness of 0.05-0.1mm, a KAM value of ≤0.1°, and an elongation of 13-22%.

2. The method for preparing GH4145 alloy foil according to claim 1, characterized in that: In the step 2, the temperature of the ingot forged into the slab is 1020°C-1050°C.

3. The method for preparing GH4145 alloy foil according to claim 1, characterized in that: In step 3, the GH4145 alloy slab is hot rolled into a strip with a thickness of 2-3 mm, and the deformation amount is 90%-95%.

4. The method for preparing GH4145 alloy foil according to claim 1, characterized in that: In step 4, water cooling is performed after the solution treatment to reduce the generation of carbides and precipitation phases, thereby reducing stress.

5. The method for preparing GH4145 alloy foil according to claim 1, characterized in that: The finished product annealing in step 7 is argon protection vacuum annealing at a temperature of 980° C. for 45 minutes.

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