Vacuum electron beam welding method for solid solution strengthening type nickel-based high-temperature alloy GH3536 strip

Abstract

The present application belongs to the technical field of high-temperature alloy strip preparation, and particularly relates to a vacuum electron beam welding method for a solid solution strengthening type nickel-based high-temperature alloy GH3536 strip. In order to prevent vaporization burn-through and incomplete penetration of the strip and fully ensure the performance of the strip, the vacuum electron beam welding method comprises strip edge treatment, strip pre-weld cleaning, butt joint weld assembly, positioning welding, formal welding and post-weld heat treatment. By controlling the welding process parameters, the present application not only has a small, flat and continuous weld width, full arc collection, but also has no defects such as holes, collapse and spatter in the welded joint, and the strength of the welded joint reaches more than 93% of the strength of the base material. The plasticity and tensile strength of the welded joint are equivalent to those of the base material, so that the welded joint has mechanical properties equivalent to those of the base material. The strip parts prepared after welding have the advantages of lightweight structure, high safety and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-temperature alloy strip preparation, and particularly relates to a vacuum electron beam welding method of a solid solution strengthening type nickel-based high-temperature alloy GH3536 strip. BACKGROUND

[0002] High-temperature alloy strip-prepared thin-wall sheet metal parts account for a considerable proportion in aerospace engines, gas turbines, missiles and other equipment, and play a decisive role in structural weight reduction, improvement and increase of engine performance. In advanced aero-engines, high-temperature alloy thin-wall parts account for more than 28%, and the honeycomb sealing device of a high thrust-to-weight ratio aero-engine mainly uses GH3536 strip (thickness of 0.1-0.3 mm), which is a solid solution strengthening type nickel-based high-temperature alloy, has excellent hot corrosion resistance, oxidation resistance, high-temperature stability and microstructure stability, can be used for a long time below 900 DEG C, and the short-time working temperature can also reach 1080 DEG C, and welding is an important means of connecting these parts. At the same time, good welding of the strip also makes it possible to mass-produce a single roll of foil with a weight of more than 500 kg. Due to the too thin thickness of the material, the welding difficulty is significantly increased, and ordinary welding methods (such as TIG, MIG, etc.) have large heat input and serious welding deformation, and are not suitable for thin material welding. The resistance welding method commonly used at present is easy to cause welding deformation due to large heat input, and in many cases will affect the use and appearance of the device; tungsten inert gas arc welding is suitable for thin plate welding, but it is also difficult to realize reliable welding of strip with a thickness of ≤0.3 mm. Electron beam welding is a high-energy density welding method, and its rapid development and wide application in modern industrial fields are because electron beam welding has a series of advantages.

[0003] Compared with other ways of fusion welding, electron beam welding has the following advantages: (1) high power density, the diameter of the electron beam focusing point is about 0.1-1 mm, and the power density of the electron beam can reach 10 6 W / cm 2Above, belongs to high-energy beam. High-energy electron beam, beam diameter is small, can form a deep and narrow penetration weld, weld depth can reach 20:1. (2) accurate, fast controllability, through the electric field, the electron beam can be fast and accurate control. (3) fast welding speed, small heat affected zone, small welding deformation, the electron beam welding speed is generally above, the electron beam weld heat affected zone is very small, sometimes almost does not exist. The characteristics of small welding heat input make the deformation of electron beam welding smaller. (4) electron beam is easy to control, the welding parameters of electron beam welding can be accurately controlled, the repeatability and stability of the parameters during welding are good. Therefore, the penetration depth, size and characteristics of the weld can be strictly controlled, and the welding quality and stability of the product are improved. (5) vacuum environment is conducive to improving the quality of the weld, vacuum electron beam welding is carried out in a vacuum chamber, which eliminates the influence of harmful gases hydrogen and oxygen in the atmosphere on the molten metal, and the chemical composition of the molten metal is pure, which improves the quality of the weld. Therefore, these characteristics make the vacuum electron beam welding more suitable for the welding of thin materials than other welding methods. SUMMARY

[0004] In order to prevent vaporization burn-through of the strip, incomplete penetration, and fully ensure the performance of the strip, the purpose of the present application is to provide a vacuum electron beam welding method for solid solution strengthening type nickel-based superalloy GH3536 strip, which can obtain a wide, flat and continuous weld by controlling the welding process parameters, and the welded joint is free of defects such as holes, collapse and spatter, and the tensile strength of the welded joint reaches more than 93% of the strength of the base material.

[0005] The technical scheme of the present application is:

[0006] A vacuum electron beam welding method for solid solution strengthening type nickel-based superalloy GH3536 strip, comprising the following steps:

[0007] (1) The edge part of the to-be-welded strip is machined to ensure the smoothness and flatness of the edge part, and the surface roughness of the edge part is less than 0.5 μm;

[0008] (2) The base material is chemically cleaned before welding, and the specific process is: degreasing → water washing → alkali washing → water washing → acid washing → water washing, and the cleaned material is dried;

[0009] (3) The strip is assembled, and in order to ensure the welding quality, the gap at the weld after assembly is ≤0.05 mm;

[0010] (4) The butt-jointed GH3536 strip is placed into the vacuum chamber of the welding machine, and the vacuum chamber of the welding machine is evacuated until the air pressure in the vacuum chamber is lower than 1×10 -4 mbar;

[0011] (5) Symmetrical positioning welding is performed on the welds by electron beam welding to control the deformation of the assembly generated in the formal welding process, and the process parameters of the symmetrical positioning welding are as follows: voltage 30 kV, welding speed 2200±10 mm / min, beam current 0.5-3 mA, welding heat input 0.4-2.5 J / mm, focusing current 1605 mA, X-direction swing amplitude 0.5 mm, and Y-direction swing amplitude 0.5 mm;

[0012] (6) Formal welding is performed on the welds of the GH3536 strip after positioning welding, and the process parameters of the formal welding are as follows: voltage 30 kV, welding speed 2200±10 mm / min, focusing current 1605 mA, beam current 1.5-9 mA, welding heat input 1.2-7.4 J / mm, X-direction swing amplitude 0.5 mm, and Y-direction swing amplitude 0.5 mm;

[0013] (7) After formal welding, the sample is taken out after 10 min of cooling in the vacuum chamber of the welding machine.

[0014] In the step (1), the thickness of the solid solution strengthened nickel-based high-temperature alloy GH3536 strip to be welded is 0.1-0.3 mm.

[0015] In the step (5), when symmetrical positioning welding is performed, for the 0.3-mm-thick strip, the electron beam current is 2-2.3 mA, the welding speed is 36.7 mm / s, and the welding heat input is 1.6-2.5 J / mm; for the 0.2-mm-thick strip, the electron beam current is 1-1.7 mA, the welding speed is 36.7 mm / s, and the welding heat input is 0.8-1.3 J / mm; and for the 0.1-mm-thick strip, the electron beam current is 0.5-0.6 mA, the welding speed is 36.7 mm / s, and the welding heat input is 0.4-0.5 J / mm.

[0016] In the step (6), when formal welding is performed, for the 0.3-mm-thick strip, the electron beam current is 6-7 mA, the welding speed is 36.7 mm / s, and the welding heat input is 4.9-7.4 J / mm; for the 0.2-mm-thick strip, the electron beam current is 3-5 mA, the welding speed is 36.7 mm / s, and the welding heat input is 2.5-4.1 J / mm; and for the 0.1-mm-thick strip, the electron beam current is 1.5-1.75 mA, the welding speed is 36.7 mm / s, and the welding heat input is 1.2-1.4 J / mm.

[0017] The vacuum electron beam welding method of the solid solution strengthening type nickel-based high-temperature alloy GH3536 strip material has a weld width of 0.7-1.2mm for the GH3536 strip material with a thickness of 0.3mm, a weld width of 0.5-1mm for the GH3536 strip material with a thickness of 0.2mm, and a weld width of 0.5-0.8mm for the GH3536 strip material with a thickness of 0.1mm.

[0018] The vacuum electron beam welding method of the solid solution strengthening type nickel-based high-temperature alloy GH3536 strip material is subjected to conventional stress relief heat treatment after welding, and the heat treatment temperature is 150±10 DEG C and the holding time is 20-30min.

[0019] The vacuum electron beam welding method of the solid solution strengthening type nickel-based high-temperature alloy GH3536 strip material has a weld joint tensile strength of more than 93% of the base material tensile strength.

[0020] The design idea of the present application is:

[0021] The thin-walled sheet metal parts prepared from the GH3536 strip material with a thickness of 0.1-0.3mm account for a considerable proportion in the field of aerospace, and need to be welded in use; meanwhile, the good welding of the strip material also makes it possible to produce the foil material in a single roll with a weight of more than 500kg. In order to prevent a series of defects such as oxidation, large deformation, incomplete penetration and burn-through of the weld, the present application adopts vacuum electron beam welding to obtain a weld with small width, flatness, no welding defects and the strength of the weld equal to that of the base material, so as to ensure the safety and reliability of the structure and the connection of the strip material. Firstly, in order to prevent welding deformation, symmetric positioning welding is adopted; secondly, high-speed vacuum electron beam welding is carried out to improve the welding efficiency and make the weld metal have rapid cooling capacity, so as to improve the solidification state of the weld metal, make the structure dense and uniform, and prevent segregation, thereby improving the strength of the welded joint; thirdly, the welding heat input is controlled to obtain a weld with small width, flatness and continuity, without subsequent polishing processing treatment, and the coarse grain zone and wide columnar crystal are avoided to prevent the deterioration of the material performance; fourthly, low-temperature stress relief heat treatment is carried out to obtain good strength and plasticity.

[0022] The present application has the following advantages and beneficial effects:

[0023] 1. The technical key of the present application is to adopt low acceleration voltage and high-speed welding parameters to carry out vacuum electron beam welding on a solid solution strengthening type nickel-based high-temperature alloy GH3536 strip material, effectively control the welding heat input, not only improve the welding efficiency, but also prevent burn-through, and is beneficial to the effective fusion of the weld root.

[0024] 2. The present application can obtain a wide, flat and continuous weld by reducing the welding heat input and precisely controlling the vacuum electron beam welding parameters. For the GH3536 strip with a thickness of 0.1-0.3 mm, the weld width is 0.5-1.2 mm, the weld is well formed, the weld surface is bright, and the welded joint is free of defects such as holes, collapse, spatter and cracks.

[0025] 3. The tensile strength of the welded joint of the present application is more than 93% of the strength of the base material. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Figure 2 is a tensile stress-strain curve of the welded joint of the GH3536 alloy strip with a thickness of 0.2 mm; in the figure, the horizontal axis Engineering strain is engineering strain (%), and the vertical axis Engineering stress is engineering stress (MPa).

[0027] Figure 2 Figure 3 is a tensile stress-strain curve of the welded joint of the GH3536 alloy strip with a thickness of 0.1 mm; in the figure, the horizontal axis Engineering strain is engineering strain (%), and the vertical axis Engineering stress is engineering stress (MPa).

[0028] Figure 3 (a) is the macroscopic morphology of the front surface of the vacuum electron beam welded joint of the GH3536 alloy strip with a thickness of 0.2 mm (beam current 3 mA, welding heat input 2.5 J / mm).

[0029] Figure 3 (b) is the macroscopic morphology of the back surface of the vacuum electron beam welded joint of the GH3536 alloy strip with a thickness of 0.2 mm (beam current 3 mA, welding heat input 2.5 J / mm).

[0030] Figure 3 (c) is the macroscopic morphology of the front surface of the vacuum electron beam welded joint of the GH3536 alloy strip with a thickness of 0.2 mm (beam current 4 mA, welding heat input 3.3 J / mm).

[0031] Figure 3 (d) is the macroscopic morphology of the back surface of the vacuum electron beam welded joint of the GH3536 alloy strip with a thickness of 0.2 mm (beam current 4 mA, welding heat input 3.3 J / mm).

[0032] Figure 3 (e) is the macroscopic morphology of the front surface of the vacuum electron beam welded joint of the GH3536 alloy strip with a thickness of 0.2 mm (beam current 5 mA, welding heat input 4.1 J / mm).

[0033] Figure 3(f) Macrograph of the back surface of the vacuum electron beam welded joint of a 0.2 mm thick GH3536 alloy strip (beam current 5 mA, welding heat input 4.1 J / mm). DETAILED DESCRIPTION

[0034] The present application is further illustrated by the following examples without thereby limiting the present application to the examples described. The experimental methods in the following examples, for which no specific conditions are indicated, are carried out according to the conventional methods and conditions.

[0035] Example

[0036] In the examples, the solid solution strengthened nickel-based superalloy GH3536 strip with thickness of 0.1 mm, 0.2 mm and 0.3 mm is selected, and the specific components and contents thereof are as follows in terms of weight percentage: Cr: 21.5, Fe: 18.5, Mo: 9.0, Co: 1.32, W: 0.37, C: 0.066, Si: 0.31, Mn: 0.82, S: 0.005, P: 0.005, and Ni: balance.

[0037] The vacuum electron beam welding method includes strip edge treatment, strip pre-weld cleaning, butt joint assembly, positioning welding, formal welding and post-weld heat treatment, and the specific steps are as follows:

[0038] 1. The edge of the to-be-welded strip is mechanically processed to ensure the smoothness and flatness of the edge, and the surface roughness of the edge is 0.3 μm;

[0039] 2. The base material, gasket and the like are chemically cleaned before welding, specifically: degreasing → water washing → alkali washing → water washing → acid washing → water washing and the like, and the cleaned parts are dried;

[0040] 3. The strips are assembled, and in order to ensure the welding quality, the gap at the weld after assembly is ≤0.05 mm.

[0041] 4. Vacuum is drawn until the air pressure in the vacuum chamber is lower than 1 × 10 -4 mbar;

[0042] 5. The electron beam welding is used to position weld the weld to control the deformation of the assembly in the formal welding process: the process parameters of the symmetrical positioning welding are as follows: the control acceleration voltage is 30 kV, the welding speed is 2200 mm / min, the focusing current is 1605 mA, the X-direction swing amplitude is 0.5 mm, the Y-direction swing amplitude is 0.5 mm, and the specific vacuum electron beam welding process is shown in Table 1.

[0043] 6. The weld of the high-temperature alloy GH3536 strip after positioning welding is formally welded, and the process parameters of the formal welding are as follows: accelerating voltage 30 kV, welding speed 2200 mm / min, focusing current 1605 mA, X direction swing amplitude 0.5 mm, Y direction swing amplitude 0.5 mm, and the specific vacuum electron beam welding process is shown in Table 1;

[0044] 7. After welding, the sample is taken out after cooling in the vacuum chamber of the welding machine for 10 min.

[0045] 8. After welding, the conventional stress relief heat treatment is carried out, the heat treatment temperature is (150±10) ℃, the holding time is 20-30 min, and the furnace is cooled to room temperature, and the purpose is to eliminate the welding stress.

[0046] Table 1

[0047]

[0048] The weld area is subjected to X-ray flaw detection, and no cracks, incomplete penetration, incomplete fusion, and weld-through samples are found in the weld. The tensile strength of the sample and the strength ratio of the sample to the base material are shown in Table 2.

[0049] Table 2

[0050]

[0051] As shown in Figure 1 , the tensile stress-strain curve of the 0.2 mm thick GH3536 alloy strip welded joint, from the figure, it can be seen that when the electron beam current of the controlled vacuum electron beam welding is 3-5 mA and the welding heat input is 2.5-4.1 J / mm, the strength of the welded joint changes slightly, and can reach 93%-97% of the strength of the base material.

[0052] As shown in Figure 2 , the tensile stress-strain curve of the 0.1 mm thick GH3536 alloy strip welded joint, from the figure, it can be seen that when the electron beam current of the controlled vacuum electron beam welding is 1.5-1.75 mA and the welding heat input is 1.2-1.4 J / mm, the strength of the welded joint changes slightly, and can reach 94%-97% of the strength of the base material.

[0053] As shown in Figure 3 (a)-(f), the macroscopic morphology of the vacuum electron beam welded weld of the 0.2 mm thick GH3536 alloy strip, from the figure, it can be seen that when the electron beam current is 3-5 mA and the welding heat input is 2.5-4.1 J / mm, the weld width is small, flat and continuous, and the arc is full, and the welded joint has no defects such as holes, collapse and spatter, and does not need subsequent polishing processing.

[0054] The implementation result shows that the welding method has small, flat and continuous weld width, full arc, and the welding joint has no defects such as hole, collapse and splash, and the tensile strength of the welding joint reaches more than 93% of the base material strength, the plasticity and tensile strength of the welding joint are equivalent to the base material, so that the welding joint has the mechanical properties equivalent to the base material, and the prepared strip part after welding has the advantages of lightweight structure, high safety and the like.

Claims

1. A vacuum electron beam welding method for solid solution strengthened nickel-based superalloy GH3536 strip, characterized in that, Includes the following steps: (1) The edges of the strip to be welded are machined to ensure the smoothness and straightness of the edges, and the surface roughness of the edges is less than 0.5μm. The thickness of the solution-strengthened nickel-based high-temperature alloy GH3536 strip to be welded is 0.3mm. (2) Chemical cleaning of the base material before welding, the specific process is: degreasing → water washing → alkaline washing → water washing → acid washing → water washing, and drying after cleaning; (3) Assemble the strip. To ensure welding quality, the gap at the weld after assembly should be ≤0.05mm. (4) Place the butted GH3536 strip into the welding machine vacuum chamber, then evacuate the welding machine vacuum chamber until the air pressure inside the vacuum chamber is lower than 1×10⁻⁶. -4 mbar; (5) Electron beam welding is used to perform symmetrical positioning welding on the weld seam in order to control the deformation of the component during the formal welding process. The process parameters for symmetrical positioning welding are as follows: voltage 30kV, welding speed 36.7mm / s, electron beam current 2~2.3mA, welding heat input 1.6J / mm~2.5J / mm, focusing current 1605mA, X-direction swing amplitude 0.5mm, Y-direction swing amplitude 0.5mm; (6) Perform formal welding on the weld of GH3536 strip after positioning welding. The process parameters for formal welding are as follows: voltage 30kV, welding speed 36.7mm / s, focusing current 1605mA, electron beam current 6~7mA, welding heat input 4.9J / mm~7.4J / mm, X-direction oscillation amplitude 0.5mm, Y-direction oscillation amplitude 0.5mm; (7) After the formal welding, the sample is taken out after cooling in the vacuum chamber of the welding machine for 10 minutes.

2. The vacuum electron beam welding method for solid solution strengthened nickel-based superalloy GH3536 strip as described in claim 1, characterized in that, For GH3536 strip with a thickness of 0.3mm, the weld width is 0.7~1.2mm.

3. The vacuum electron beam welding method for solid solution strengthened nickel-based superalloy GH3536 strip as described in claim 1, characterized in that, After welding, conventional stress-relieving heat treatment is performed at a temperature of 150±10℃ and a holding time of 20~30min.

4. The vacuum electron beam welding method for solid solution strengthened nickel-based superalloy GH3536 strip as described in claim 1, characterized in that, The tensile strength of the welded joint is more than 93% of the tensile strength of the base material.

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