Preparation method of nickel-based wrought superalloy strip capable of increasing weight of single coil

Abstract

The invention belongs to the technical field of preparation of high-temperature alloy strips for aerospace, and particularly relates to a preparation method of a nickel-based wrought high-temperature alloy strip capable of increasing the weight of a single coil. The method comprises the following steps: firstly, carrying out vacuum electron beam welding on a nickel-based wrought superalloy blank plate: before welding, carrying out chemical cleaning on base metal, assembling, clamping, vacuumizing, carrying out segmented electron beam welding, cooling in a vacuum chamber, and optimizing a vacuum electron beam welding process to obtain an excellent welding seam which is well formed and free of pores and cracks; and then the recrystallization grain size of the nickel-based wrought superalloy strip and the welded joint is effectively controlled by selecting the deformation amount of the middle rolling process and the annealing system. The nickel-based wrought superalloy strip prepared through the method is high in single coil weight and good in strip mechanical property, equal-strength matching is achieved between a welded joint and base metal, and the room-temperature mechanical properties of the nickel-based wrought superalloy strip and the welded joint meet the requirements that the yield strength Rp0.2 is not lower than 370 MPa, the tensile strength Rm is not lower than 780 MPa, and the room-temperature ductility A is not lower than 25%.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of high-temperature alloy strips for aerospace, and in particular relates to a method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil. Background Art

[0002] GH3536 is a nickel-based deformable high-temperature alloy with a high content of Fe, which is mainly strengthened by solid solution of Cr and Mo. It has good oxidation resistance and corrosion resistance, medium endurance and creep strength below 900℃, good cold and hot processing formability and welding performance. Its strip can be used to prepare complex thin-walled structural parts such as aircraft engine combustion liners, turbine exhaust components, and aircraft cabin heaters. It plays a decisive role in reducing the structure, improving and enhancing engine performance, and occupies a considerable proportion. The American SMC (Special Metals Corporation) has achieved coil rolling of high-temperature alloy strips, with a single coil weight of more than 10 tons, and its performance is stable, with matching strength and toughness, and good stamping plasticity, representing the highest level and development direction of metal special profiles.

[0003] In order to achieve the preparation of high-temperature alloys with high single-coil weight, the plate blanks for preparing the strip need to be welded and then rolled after connection. In order to ensure the quality of the welded joints of the blanks after welding and to match the mechanical properties of the welded joints with the strip parent material after rolling, the blank welding process needs to be precisely controlled. Due to the thin thickness of the strip, welding is difficult. Ordinary welding methods (such as TIG, MIG, etc.) have large heat input and severe welding deformation, which are not suitable for welding thin materials. In addition, the cold-rolled GH3536 has high strength (yield strength can reach more than 1500MPa) but poor plasticity (elongation generally does not exceed 5%). It must be subjected to subsequent annealing treatment to obtain stable strong and plastic properties in order to meet the subsequent use requirements of precision stamping of workpieces. Summary of the invention

[0004] In view of the technical problems existing in the existing preparation of high-single-coil weight high-temperature alloy strips and good strength and plasticity control, the present invention provides a method for preparing high-single-coil weight nickel-based deformed high-temperature alloy strips and controlling their performance. The GH3536 alloy strip prepared by the present invention has high single-coil weight, good strip mechanical properties, and the welded joint achieves equal strength matching with the base material.

[0005] The technical solution of the present invention is:

[0006] A method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil, wherein vacuum electron beam welding is performed on a nickel-based deformed high-temperature alloy blank plate, comprising the following steps:

[0007] (1) The edges of the blanks to be welded must be machined to ensure the smoothness and straightness of the edges, and the surface roughness of the edges is less than 0.5 μm;

[0008] (2) Chemically clean the base material before welding and dry it after cleaning;

[0009] (3) The blank is welded. To ensure the welding quality, the gap at the weld after assembly is ≤0.1mm;

[0010] (4) Use vacuum electron beam welding to perform positioning welding on the weld to control the deformation of the component during the formal welding process;

[0011] (5) Use vacuum electron beam welding to perform formal welding on the weld;

[0012] (6) After welding, cool in a vacuum chamber for 15 minutes;

[0013] (7) Carry out X-ray inspection on the weld area. No cracks, incomplete penetration or incomplete fusion are allowed inside the entire weld.

[0014] In the method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil, in step (4), the process parameters for positioning welding are as follows: voltage 60 kV, welding speed 1000 mm / min, focusing current 2325-2345 mA, beam current 8.5-9.5 mA, welding heat input 30 J / mm-34 J / mm, and swing amplitude in the X and Y directions 0.6 mm.

[0015] The method for preparing a nickel-based deformed high-temperature alloy strip that can increase the weight of a single coil is as follows: in step (5), the formal welding adopts segmented welding, and its process parameters are as follows: for the first 70% of the length of the weld, the voltage is 60 kV, the welding speed is 1000 mm / min, the focusing current is 2325-2345 mA, the beam current is 27-28 mA, the welding heat input is 97 J / mm-100 J / mm, and the swing amplitude in the X and Y directions is 0.6 mm; for the last 30% of the length of the weld, the voltage is 60 kV, the welding speed is 1000 mm / min, the focusing current is 2325-2345 mA, the beam current is 26-27 mA, the welding heat input is 94 J / mm-97 J / mm, and the swing amplitude in the X and Y directions is 0.6 mm.

[0016] The method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil comprises the following steps: performing four rolling processes on a precision rolling mill on a nickel-based deformed high-temperature alloy blank plate after welding, wherein the deformation amounts of the first two rolling processes are 30% to 40%, and the deformation amounts of the last two rolling processes are 50% to 60%. The thickness of the rolled strip is controlled to be 0.3 to 0.5 mm, so that the nickel-based deformed high-temperature alloy strip has deformation energy storage that is beneficial to the nucleation of recrystallization in the later stage.

[0017] The method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil is characterized in that after each rolling process is completed, a high-temperature intermediate flexible bright annealing is immediately performed, and the annealing temperature between the rolling processes is controlled as follows: after the first three rolling processes, the annealing temperature is 1110-1150°C, and the tape feed speed is 10-20 m / min; after the last rolling process, the annealing temperature is 1050-1100°C, and the tape feed speed is 0.5-1 m / min.

[0018] In the method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil, the annealing equipment is a continuous ammonia decomposition heat treatment furnace or a hydrogen protection continuous heat treatment furnace.

[0019] The method for preparing a nickel-based deformed high-temperature alloy strip that can increase the weight of a single coil is described. The nickel-based deformed high-temperature alloy is a GH3536 alloy. The room temperature mechanical properties of the GH3536 alloy strip and the welded joint meet the following requirements: the yield strength Rp0.2 is not less than 370 MPa, the tensile strength Rm is not less than 780 MPa, the room temperature elongation A is not less than 25%, and the welded joint after rolling achieves equal strength matching with the parent material.

[0020] The design concept of the present invention is:

[0021] The vacuum electron beam has high energy density, narrow weld and heat-affected zone, large weld depth-to-width ratio, small welding deformation, and easy and precise control of process parameters. It does not require the use of welding materials such as welding wire or welding rod, thus avoiding the introduction of foreign inclusions or composition segregation caused by composition differences. The present invention uses a vacuum electron beam welder to perform segmented welding on the GH3536 billet sheet, and then ensures the surface quality of the GH3536 alloy strip by precision rolling forming. Through the intermediate pass "deformation-annealing" and the control of the final pass deformation amount and annealing system selection, the recrystallized grain size of the GH3536 alloy strip and the welded joint is effectively controlled, so that the strength and plasticity at the welded joint are basically consistent with the parent material, achieving the purpose of preparing a high-strength and high-plasticity high-temperature alloy strip with high single coil weight.

[0022] The present invention adopts a vacuum electron beam welding method to control the welding process parameters of the plate. The rolling-annealing process of the blank plate after welding is optimized to obtain a high-temperature alloy plate with a high single-roll weight, in which the welded joint and the parent material are equally matched and the mechanical properties meet the requirements. First, by accurately controlling the vacuum electron welding parameters in sections, a small-width, flat, and continuous weld is obtained, and the welded joint has no defects such as holes, collapse, and spatter, so that the strength coefficient of the welded joint can reach more than 95%; secondly, controlling the intermediate deformation amount and annealing system to prevent the occurrence of problems such as cracking and breaking of the plate is the premise for ensuring the final plate performance; then, accumulating large deformations to make the GH3536 alloy strip and the welded joint have higher deformation energy storage, establish the relationship between the deformation amount of the GH3536 strip-recrystallization annealing process and the mechanical properties, control the uniform growth of the grain size, and further ensure the acquisition of a high-temperature alloy strip with high single-roll weight and high strength and plasticity.

[0023] After the blank plate is welded by vacuum electron beam, the cast structure of the welded joint can be completely eliminated after multiple rolling + annealing treatments, and it can be transformed into a processed state. The fusion line and the heat-affected zone are completely eliminated; the strength and plasticity at the welded joint are basically the same as those of the parent material. Under different annealing systems, the grains are promoted to grow uniformly, and while eliminating work hardening, the average grain size of the GH3536 strip is controlled to further ensure the strong plasticity. Therefore, the present invention develops a high-temperature alloy with a high single coil weight and a 0.3-0.5 mm thick GH3536 strip with stable strong plasticity mechanical properties by optimizing the vacuum electron beam welding process and the rolling-annealing process of the blank plate.

[0024] The advantages and beneficial effects of the present invention are:

[0025] 1. The present invention performs vacuum electron beam welding on GH3536 blank plates, and obtains a flat and continuous weld by precisely controlling welding parameters in sections, and the weld joint has no defects such as holes, collapse, and spatter.

[0026] 2. The present invention designs the rolling deformation and annealing process of the GH3536 alloy plate after welding, so that the rolling deformation is more sufficient, the internal structure is more uniform, and the intermediate high temperature rapid annealing is performed to suppress the coarsening of the internal grains and adjust the grain size and uniformity of the internal structure of the strip and the welded joint.

[0027] 3. The present invention realizes the stable production of high-strength and high-plasticity GH3536 alloy strip with high single-roll weight, and the performance is uniform and stable, meeting the high-quality requirements. The welded joints of the GH3536 alloy strip achieve equal strength matching with the parent material, and the room temperature mechanical properties can meet the following requirements: the yield strength (Rp0.2) is not less than 370MPa, the tensile strength (Rm) is not less than 780MPa, and the room temperature elongation (A) is not less than 25%.

[0028] 4. The GH3536 alloy strip prepared by the present invention has excellent performance, can achieve industrial production of high single coil weight, and meet the use requirements of high-performance aircraft engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1-Figure 2 For the welding joint of blank plate ( Figure 1 ) and welded joints after multi-pass rolling annealing ( Figure 2 ) is an electron backscatter diffraction (EBSD) pattern. DETAILED DESCRIPTION

[0030] In the specific implementation process, the single roll weight of the domestically prepared strip is low, the performance is unstable, and the reliability is difficult to guarantee. The specific process of vacuum electron beam welding of GH3536 blank plate by the present invention is: chemical cleaning of the parent material before welding → assembly and clamping → vacuum → segmented electron beam welding → cooling in a vacuum chamber, and optimizing the vacuum electron beam welding process to obtain a good weld with good forming, no pores and cracks; then through the selection of the deformation amount of the intermediate rolling process and the annealing system, the recrystallized grain size of the GH3536 alloy strip and the welded joint is effectively controlled. The single roll weight of the GH3536 alloy strip prepared by the present invention is high, the mechanical properties of the strip are good, the welded joint and the parent material are equally matched, and the room temperature mechanical properties of the GH3536 alloy strip and the welded joint meet the requirements.

[0031] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods without specific conditions in the following examples are based on conventional methods and conditions.

[0032] Example 1

[0033] In this embodiment, a GH3536 alloy strip coil with a thickness of 4.5 mm and a matte surface finish is selected as the blank plate. Its specific composition and content, by weight percentage, are: Cr: 20.5, Fe: 18.8, Mo: 9.06, Co: 1.02, W: 0.60, C: 0.094, Al: 0.15, Si: 0.25, Mn: 0.42, S<0.001, P: 0.004, and Ni as a remainder.

[0034] The specific steps of vacuum electron beam welding of blank plates are as follows:

[0035] 1. The edges of the plates to be welded are machined to ensure smoothness and straightness of the edges. The surface roughness of the edges is 0.3μm;

[0036] 2. Chemically clean the base material, liner, etc. before welding, and dry them after cleaning;

[0037] 3. Assemble the plates. To ensure the welding quality, the gap at the weld should be ≤0.1mm after assembly.

[0038] 4. Evacuate the vacuum chamber until the pressure is lower than 1×10 -4 mbar;

[0039] 5. Use electron beam welding to perform positioning welding on the weld to control the deformation of the component during the formal welding process.

[0040] The process parameters of positioning welding are as follows: voltage 60 kV, welding speed 1000 mm / min, focusing current 2345 mA, beam current 9.5 mA, welding heat input 34 J / mm, swing amplitude in X and Y directions 0.6 mm;

[0041] 6. Formal welding: Formal welding is performed on the weld of the high-temperature alloy GH3536 plate after positioning welding. Segment welding is adopted. The process parameters of formal welding are as follows: for the first 70% of the length of the weld, the voltage is 60kV, the welding speed is 1000mm / min, the focusing current is 2345mA, and the swing amplitude in the X and Y directions is 0.6mm; for the last 30% of the length of the weld, the voltage is 60kV, the welding speed is 1000mm / min, the focusing current is 2345mA, and the swing amplitude in the X and Y directions is 0.6mm. The electron beam current and welding heat input parameters of segment welding are shown in Table 1:

[0042] Table 1

[0043]

[0044] 7. After welding, cool in the vacuum chamber for 15 minutes and then take out the sample;

[0045] 8. X-ray inspection was carried out on the weld area, and no cracks, incomplete penetration, or incomplete fusion were found inside the weld.

[0046] The design parameters of intermediate rolling-annealing of the 4.5 mm thick plate after welding are shown in Table 2:

[0047] Table 2

[0048] path Thickness before rolling / mm Thickness after rolling / mm Deformation / % Annealing temperature / ℃ Tape speed / (m / min) First rolling process 4.5 3.0 33.3 1150 20 Second rolling process 3.0 2.0 33.3 1145 16 The third rolling process 2.0 1.0 50.0 1130 12 Fourth rolling process 1.0 0.5 50.0 1080 1

[0049] The final rolled 0.5 mm thick strip was annealed at 1080°C with a strip speed of 1 m / min.

[0050] The obtained strips were tested, and the performance indicators of the welded joints of the 0.5mm thick strips were: tensile strength 793MPa, yield strength 400MPa, and elongation 29.8%; the tensile strength of the 0.5mm thick strips was 792MPa, yield strength 375MPa, and elongation 34%. After rolling and annealing, the strength of the welded joints achieved equal strength matching with the parent material.

[0051] like Figure 1-Figure 2 As shown, the blank plate welding joint ( Figure 1 ) and welded joints after multi-pass rolling annealing ( Figure 2 ) shows that the temperature of the molten pool area of ​​the initial welding joint drops rapidly after the electron beam leaves, and then the molten metal at both ends of the molten pool begins to nucleate non-uniformly, and the grains grow outward from the center of the molten pool to form tightly arranged columnar crystal regions with different grain orientations from the parent material. After multiple rolling and annealing processes, the grain orientation of the joint has tended to be consistent with that of the parent material, and the average grain size is small, indicating that multiple rolling and annealing processes can improve the structure of the joint.

[0052] Example 2

[0053] In this embodiment, a GH3536 alloy strip coil with a thickness of 4.0 mm and a matte surface finish is selected as the blank plate, and vacuum electron beam welding is performed on it. The difference from Example 1 is the welding parameters of positioning welding and formal welding.

[0054] The process parameters of positioning welding are: voltage 60kV, welding speed 1000mm / min, focusing current 2325mA, beam current 8.5mA, welding heat input 30J / mm, swing amplitude in X and Y directions 0.6mm;

[0055] The process parameters of formal welding are as follows: for the first 70% of the length of the weld, the voltage is 60kV, the welding speed is 1000mm / min, the focusing current is 2325mA, and the swing amplitude in the X and Y directions is 0.6mm; for the last 30% of the length of the weld, the voltage is 60kV, the welding speed is 1000mm / min, the focusing current is 2325mA, and the swing amplitude in the X and Y directions is 0.6mm. The electron beam current and welding heat input parameters of segmented welding are shown in Table 3:

[0056] Table 3

[0057]

[0058] After welding, the samples were taken out after cooling in the vacuum chamber for 15 min;

[0059] The weld area was subjected to X-ray inspection, and no cracks, incomplete penetration, or incomplete fusion were found inside the weld.

[0060] The design parameters of intermediate rolling-annealing of 4.0 mm thick plate after welding are shown in Table 4:

[0061] Table 4

[0062] path Thickness before rolling / mm Thickness after rolling / mm Deformation / % Annealing temperature / ℃ Tape speed / (m / min) First rolling process 4.0 2.5 37.5 1145 18 Second rolling process 2.5 1.6 36.0 1140 15 The third rolling process 1.6 0.7 56.3 1110 10 Fourth rolling process 0.7 0.3 57.1 1050 0.5

[0063] The final rolled 0.3 mm thick strip was annealed at 1050°C with a strip speed of 0.5 m / min.

[0064] The obtained strips were tested, and the performance indicators of the welded joints of the 0.3mm thick strips were: tensile strength 809MPa, yield strength 392MPa, and elongation 26.6%; the tensile strength of the 0.3mm thick strips was 801MPa, yield strength 382MPa, and elongation 30%. After rolling and annealing, the strength of the welded joints achieved equal strength matching with the parent material.

[0065] The implementation results show that the present invention performs vacuum electron beam welding on GH3536 billet and plate, and obtains a flat and continuous weld by precisely controlling the welding parameters in sections, and the weld joint is free of defects such as holes, collapse, and spatter, and the rolling-annealing process of the billet and plate after welding is optimized. This method can achieve uniform internal structure of the strip and the strip weld joint, and can obtain a high-temperature alloy strip with high single coil weight in which the weld joint and the parent material are equally matched in strength and the mechanical properties meet the requirements.

Claims

1. A method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil, characterized in that: The vacuum electron beam welding of nickel-based deformed high-temperature alloy blanks and plates comprises the following steps: (1) The edges of the blanks to be welded must be machined to ensure the smoothness and straightness of the edges, and the surface roughness of the edges is less than 0.5 μm; (2) Chemically clean the base material before welding and dry it after cleaning; (3) The blank is welded. To ensure the welding quality, the gap at the weld after assembly is ≤0.1mm; (4) Use vacuum electron beam welding to perform positioning welding on the weld to control the deformation of the component during the formal welding process; (5) Use vacuum electron beam welding to perform formal welding on the weld; (6) After welding, cool in a vacuum chamber for 15 minutes; (7) Carry out X-ray inspection on the weld area. No cracks, incomplete penetration or incomplete fusion are allowed inside the entire weld.

2. The method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil according to claim 1, characterized in that: In step (4), the process parameters of positioning welding are as follows: voltage 60kV, welding speed 1000mm / min, focusing current 2325~2345mA, beam current 8.5~9.5mA, welding heat input 30J / mm~34J / mm, and swing amplitude in X and Y directions 0.6mm.

3. The method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil according to claim 1, characterized in that: In step (5), the formal welding adopts segmented welding, and its process parameters are as follows: for the first 70% of the length of the weld, the voltage is 60kV, the welding speed is 1000mm / min, the focusing current is 2325-2345mA, the beam is 27-28mA, the welding heat input is 97J / mm-100J / mm, and the swing amplitude in the X and Y directions is 0.6mm; for the last 30% of the length of the weld, the voltage is 60kV, the welding speed is 1000mm / min, the focusing current is 2325-2345mA, the beam is 26-27mA, the welding heat input is 94J / mm-97J / mm, and the swing amplitude in the X and Y directions is 0.6mm.

4. The method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil according to any one of claims 1 to 3, characterized in that: The nickel-based deformed high-temperature alloy billet and plate after welding are rolled in four rolling processes on a precision rolling mill. The deformation amounts of the first two rolling processes are 30% to 40%, and the deformation amounts of the last two rolling processes are 50% to 60%. The thickness of the rolled strip is controlled to be 0.3 to 0.5 mm, so that the nickel-based deformed high-temperature alloy strip has deformation energy storage that is beneficial to the later recrystallization nucleation.

5. The method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil as claimed in claim 4, characterized in that: After each rolling process is completed, high-temperature intermediate flexible bright annealing is carried out immediately. The annealing temperature between rolling processes is controlled as follows: after the first three rolling processes, the annealing temperature is 1110-1150°C, and the belt speed is 10-20m / min; after the last rolling process, the annealing temperature is 1050-1100°C, and the belt speed is 0.5-1m / min.

6. The method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil as claimed in claim 5, characterized in that: The annealing equipment is a continuous ammonia decomposition heat treatment furnace or a hydrogen protection continuous heat treatment furnace.

7. The method for preparing a nickel-based deformed high-temperature alloy strip capable of increasing the weight of a single coil as claimed in claim 1, characterized in that: The nickel-based deformed high-temperature alloy is GH3536 alloy. The room temperature mechanical properties of GH3536 alloy strip and welded joints meet the following requirements: yield strength Rp0.2 is not less than 370MPa, tensile strength Rm is not less than 780MPa, room temperature elongation A is not less than 25%, and the welded joint after rolling achieves equal strength matching with the parent material.

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