Vacuum electron beam welding method for nickel-based deformation high-temperature alloy foil for aero-engine

Abstract

The invention belongs to the technical field of preparation of high-temperature alloy foils, and particularly relates to a vacuum electron beam welding method of a nickel-based deformation high-temperature alloy foil for an aero-engine. A vacuum electron beam welding method is adopted for the micron-scale (30-80 microns) nickel-based deformed high-temperature alloy foil, and the vacuum electron beam welding method comprises the following steps of: carrying out chemical cleaning on a base material, a gasket and the like before welding, assembling and clamping, vacuumizing, carrying out electron beam welding, cooling in a vacuum chamber, and optimizing a vacuum electron beam welding process, so that the micron-scale (30-80 microns) nickel-based deformed high-temperature alloy foil is obtained. And the tensile strength of a welding joint can reach more than 95% of the tensile strength of a base material. Welding is stable, the width of a welding seam is uniform, splashing is small, arc suppression is full, the tensile strength of a welding joint is equivalent to that of base metal, and structural safety and reliability are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature alloy foil preparation, and in particular relates to a vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aviation engines. Background Art

[0002] High-temperature alloy profiles with a thickness greater than 1 mm are usually called plates, those with a thickness of 0.1 to 0.8 mm are called strips, and those with a thickness less than 0.1 mm are called foils. The thickness of metal foil is much smaller than the other two dimensions, and it is a typical micron-scale material. GH3536 is a solid solution-strengthened nickel-based high-temperature alloy with excellent thermal corrosion resistance, oxidation resistance, high-temperature stability and structural stability. It can be used for a long time below 900°C, and the short-term working temperature can reach 1080°C. GH3536 alloy foil can be used to prepare complex thin-walled high-temperature resistant structural parts such as aircraft engine combustion liners, turbine exhaust components, and aircraft cabin heaters. It is a type of micron-scale material with important application backgrounds in the fields of aviation and aerospace. Thin-walled sheet metal parts prepared from micron-scale GH3536 alloy foil account for a considerable proportion of the combustion chambers and turbines of aircraft engines, and welding is an important means of connecting these parts. Traditional welding process methods do not concentrate heat, have low welding efficiency, large deformation of parts, easy oxidation of welds, and easy welding defects. The aerospace industry has high requirements for welding quality, especially for parts and components that are in service under high temperature conditions. Welding defects are one of the important ways for products to fail. Vacuum electron beam welding does not require the introduction of protective gas. Parts are welded in a vacuum state, which greatly reduces the pollution of the surrounding environment to the weld. It has the characteristics of strong penetration ability, fast welding speed, small heat-affected zone, small welding stress, large weld depth-to-width ratio, and good welding quality. It is widely used in aerospace and other fields. When GH3536 alloy foil is electron beam welded, the parent metal undergoes a process of first being heated and melted and then cooled and solidified. In this process, different welding heat inputs will cause the temperature rise and cooling rate of the weld metal to change, resulting in changes in the microstructure of the weld area, which ultimately affects the mechanical properties of the welded joint. Considering the safety and reliability of the structure, it is generally required that the weld strength is at least equal to the parent material strength, that is, the "equal strength" design principle. Summary of the invention

[0003] The purpose of the present invention is to provide a vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines, which has the advantages of small deformation, beautiful weld formation, and no defects such as cracks and pores. Under optimized welding process parameters, the tensile strength of the joint can reach more than 95% of the tensile strength of the parent material.

[0004] The technical solution of the present invention is:

[0005] A vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines comprises the following steps:

[0006] Step 1: Use nickel-based deformed high-temperature alloy foil with a thickness of 0.03-0.08 mm, and the liner is 2-4 mm thick 316 stainless steel plate;

[0007] Step 2: Chemically clean the base metal and liner before welding. The specific process is: degreasing → water washing → alkali washing → water washing → acid washing → water washing, and drying after cleaning;

[0008] Step 3: Assembly and clamping, the assembly gap is less than 0.01mm;

[0009] Step 4: Evacuate the chamber and perform electron beam welding, controlling the acceleration voltage to 30 kV and the focusing current to 1600 mA;

[0010] Step 5: After welding, cool in the vacuum chamber for 5 minutes and then take out the sample.

[0011] The vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines is as follows: in the third step, the cleaned nickel-based deformed high-temperature alloy foil is placed on a horizontal workbench. In order to avoid the weldment from shifting due to deformation during welding, the weld is aligned with the slots of the upper and lower gaskets, and the gaskets are clamped by a metal clamp to achieve assembly of the weldment.

[0012] The vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines, in the fourth step, for 0.03mm thick foil: electron beam current 0.15-0.2mA, welding speed 36.7mm / s, welding heat input 0.12-0.16J / mm; for 0.05mm thick foil: electron beam current 0.3-0.4mA, welding speed 36.7mm / s, welding heat input 0.2-0.3J / mm; for 0.08mm thick foil: electron beam current 1.1-1.3mA, welding speed 36.7mm / s, welding heat input 0.9-1.1J / mm.

[0013] The vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines has a weld width of 0.4-0.7 mm for a foil with a thickness of 0.08 mm, a weld width of 0.1-0.2 mm for a foil with a thickness of 0.05 mm, and a weld width of 0.1-0.15 mm for a foil with a thickness of 0.03 mm.

[0014] The vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aviation engines is described. The nickel-based deformed high-temperature alloy is GH3536 alloy, and the tensile strength of the welded joint is more than 95% of the tensile strength of the base material.

[0015] The design idea of ​​the present invention is:

[0016] Thin-walled sheet metal parts made of nickel-based high-temperature alloy GH3536 foil in the combustion chamber and turbine of aircraft engines need to be welded. In order to prevent oxidation of the weld, large deformation of parts, and a series of defects such as incomplete penetration and welding, the present invention adopts vacuum electron beam welding to obtain welds without welding defects and achieve strong matching of weld strength and parent material strength to ensure the safety and reliability of the structure. First, in order to prevent welding deformation, reduce positioning welding procedures, and improve welding efficiency, a groove-type gasket is designed, and the foil is pressed and fixed with an assembly tool; second, the welding speed of vacuum electron beam welding is controlled to achieve high-speed welding, increase welding efficiency, increase the cooling speed of the weld, improve the crystallization state of the weld metal, and obtain a dense and uniform structure, thereby improving the strength of the weld joint; third, the welding heat input is controlled to obtain a small, flat, and continuous weld without the need for subsequent grinding and processing, and avoid the appearance of coarse grain areas to prevent deterioration of material properties. In summary, the vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines proposed in the present invention has the advantages of small deformation, beautiful weld formation, and no defects such as cracks and pores. Under optimized welding process parameters, the tensile strength of the joint can reach more than 95% of the tensile strength of the parent material.

[0017] The advantages and beneficial effects of the present invention are:

[0018] 1. The vacuum electron beam welding process for nickel-based deformed high-temperature alloy GH3536 foil proposed by the present invention has concentrated energy, high power density, low heat input, small heat-affected zone, small deformation and high welding speed.

[0019] 2. The weld width of the 0.08mm thick foil of the present invention is 0.4-0.7mm, the weld width of the 0.05mm thick foil is 0.1-0.2mm, and the weld width of the 0.03mm thick foil is 0.1-0.15mm. There are no defects such as cracks and pores, and the welding process is stable.

[0020] 3. The present invention adopts vacuum electron beam welding method for micron-scale (30-80 μm) GH3536 alloy foil, and obtains excellent welds with good forming, no pores and cracks by optimizing the welding process, and the tensile strength of the welded joint reaches more than 95% of the tensile strength of the parent material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the liner used for welding GH3536 foil.

[0022] Figure 2 (a) The front macroscopic morphology of the EBW weld of 50 μm thick GH3536 alloy foil when the welding heat input is 0.25 J / mm.

[0023] Figure 2 (b) The macroscopic morphology of the back side of the EBW weld of 50 μm thick GH3536 alloy foil when the welding heat input is 0.25 J / mm.

[0024] Figure 2 (c) The front macroscopic morphology of the EBW weld of 50 μm thick GH3536 alloy foil when the welding heat input is 0.3 J / mm.

[0025] Figure 2 (d) shows the macroscopic morphology of the back side of the EBW weld of a 50 μm thick GH3536 alloy foil when the welding heat input is 0.3 J / mm. DETAILED DESCRIPTION

[0026] In the specific implementation process, for the welding of GH3536 foil, since the material is very thin and easy to burn through, in order to obtain a continuous weld without burn-through, the key is to accurately control the parameters. The inventors of the present invention have optimized the vacuum electron beam welding process through research, and thus proposed a vacuum electron beam welding method for micron-scale (30-80μm) GH3536 alloy foil. The process is: chemically clean the base material, gasket, etc. before welding → assemble and clamp → evacuate → perform electron beam welding → cool in a vacuum chamber.

[0027] 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.

[0028] Example

[0029] In the embodiment, GH3536 alloy foil with specifications of thickness of 0.03 mm, 0.05 mm and 0.08 mm is selected, and its specific composition and content are as follows by weight percentage: Cr: 21.8, Fe: 19.8, Mo: 8.66, Co: 0.82, W: 0.57, C: 0.086, Al: 0.19, Si: 0.21, Mn: 0.72, Cu: 0.05, S: 0.001, P: 0.005, and Ni balance.

[0030] The vacuum electron beam welding method is adopted, and the specific steps are as follows:

[0031] 1. GH3536 alloy foil with thickness of 0.03mm, 0.05mm and 0.08mm, and the liner is 316 stainless steel plate with thickness of 2-4mm;

[0032] 2. Before welding, the base material, gasket, etc. shall be chemically cleaned, specifically: degreasing → water washing → alkali washing → water washing → acid washing → water washing, etc., and then dried after cleaning;

[0033] 3. Butt the parts to be welded, ensure that the gap between the two welds is no more than 0.001mm, align the weld with the upper and lower gasket slots, and clamp the gasket with a metal clamp to achieve assembly of the welded parts.

[0034] 4. Evacuate the chamber and perform electron beam welding. The process parameters are as follows: control the acceleration voltage to 30 kV, the focusing current to 1600 mA, and the specific vacuum electron beam welding process is shown in Table 1.

[0035] Table 1

[0036]

[0037] The weld area was subjected to X-ray flaw detection, and no cracks, incomplete penetration, or incomplete fusion were found inside the weld. The tensile strength of the welded sample and the proportion of its tensile strength to the tensile strength of the base material are shown in Table 2.

[0038] Table 2

[0039]

[0040] like Figure 1 As shown in the figure, it is a schematic diagram of the liner used for welding GH3536 foil. It can be seen from the figure that the designed grooved liner and the assembly tooling are used to press and fix the foil to prevent welding deformation, reduce the positioning welding process and improve welding efficiency.

[0041] like Figure 2 (a)-(d) show the macroscopic morphology of the EBW weld of 50 μm thick GH3536 alloy foil. It can be seen from the figure that no matter when the welding heat input is 0.25 J / mm or 0.3 J / mm, the front and back sides of the weld are small, flat, and continuous, and no subsequent grinding processing is required.

[0042] The implementation results show that the vacuum electron beam welding method adopted in the present invention can not only make the welding stable, the weld width uniform, the spatter small and the arc closing full, but also the tensile strength of the weld joint is equivalent to that of the parent material, the structure has safety and reliability, the weld is well formed, the weld surface is bright, and there are no pores or cracks.

Claims

1. A vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines, characterized in that: The following steps are involved: Step 1: Use nickel-based deformed high-temperature alloy foil with a thickness of 0.03-0.08 mm, and the liner is 2-4 mm thick 316 stainless steel plate; Step 2: Chemically clean the base metal and liner before welding. The specific process is: degreasing → water washing → alkali washing → water washing → acid washing → water washing, and drying after cleaning; Step 3: Assembly and clamping, the assembly gap is less than 0.01mm; Step 4: Evacuate the chamber and perform electron beam welding, controlling the acceleration voltage to 30 kV and the focusing current to 1600 mA; Step 5: After welding, cool in the vacuum chamber for 5 minutes and then take out the sample.

2. The vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines according to claim 1, characterized in that: In the third step, the cleaned nickel-based deformed high-temperature alloy foil is placed on a horizontal workbench. In order to avoid the weldment from shifting due to deformation during welding, the weld is aligned with the slots of the upper and lower gaskets, and the gaskets are clamped with metal clamps to achieve assembly of the weldment.

3. The vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines according to claim 1, characterized in that: In the fourth step, for 0.03mm thick foil: electron beam current 0.15~0.2mA, welding speed 36.7mm / s, welding heat input 0.12~0.16J / mm; for 0.05mm thick foil: electron beam current 0.3~0.4mA, welding speed 36.7mm / s, welding heat input 0.2~0.3J / mm; for 0.08mm thick foil: electron beam current 1.1~1.3mA, welding speed 36.7mm / s, welding heat input 0.9~1.1J / mm.

4. The vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines according to claim 3, characterized in that: For foil with a thickness of 0.08 mm, the weld width is 0.4 to 0.7 mm; for foil with a thickness of 0.05 mm, the weld width is 0.1 to 0.2 mm; for foil with a thickness of 0.03 mm, the weld width is 0.1 to 0.15 mm.

5. The vacuum electron beam welding method for nickel-based deformed high-temperature alloy foil for aircraft engines according to claim 1, characterized in that: The nickel-based deformed high-temperature alloy is GH3536 alloy, and the tensile strength of the welded joint is more than 95% of the tensile strength of the base material.

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