Brazing method for aero-engine nozzle valve

Abstract

The invention discloses a brazing method for an aero-engine nozzle valve. The brazing method comprises the following steps that S1, a plurality of bosses are machined on a valve base; s2, strip-shaped brazing filler metal is pre-arranged on the periphery of the valve base; s3, the valve base is installed in the nozzle shell; and S4, a gap between the valve base and the nozzle shell is welded. The method has the beneficial effects that in general, the problems that foil-shaped brazing filler metal is preset, the energy storage welding process is complex and low in efficiency are solved, the technological process is simplified, the eccentric problem of a pipe opening is solved, the manufacturing period is greatly shortened, and the cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of welding, in particular to a method for brazing a nozzle valve of an aero-engine. Background Art

[0002] Unlike fusion welding, the base material joint does not melt during brazing. Brazing uses a brazing filler metal with a melting point lower than the base material solidus. It is placed at the brazing joint. When the heating temperature exceeds the melting point of the brazing filler metal but is lower than the base material solidus, the brazing filler metal melts. The liquid brazing filler metal melts and wets the base material, flows and fills the gap in the base material joint, diffuses with the base material, and finally cools and solidifies, thereby welding the two pieces of material together.

[0003] The engine nozzle has a complex structure and requires extensive brazing technology. It is required to be welded and formed in one go. Any carelessness will lead to scrapping, resulting in huge economic losses. Especially when welding the nozzle valve, it is difficult to ensure the pre-setting of brazing material and gap control due to the obstruction of the valve housing. At the same time, due to the eccentricity of the valve and the base during assembly, the gap is uneven, resulting in defects such as partial incomplete welding and shrinkage holes.

[0004] For the above problems, the industry generally adopts the method of plugging and pre-setting foil brazing material, that is, a small amount of foil of the same material as the parent material is pre-stuffed into the gap during assembly, or a foil brazing material equal to the gap is directly pre-set to ensure a uniform gap ("Research on Brazing Process of Nozzle Shell Assembly" - Yang Shuo used amorphous foil strips and paste brazing material in combination, and obtained a qualified welded joint after adjusting the brazing gap). Although this method can weld qualified products, the solution will greatly reduce production efficiency in mass production due to its complex process. Since the gap itself is very small, it is difficult to assemble after pre-setting foil brazing, and the technical level of workers is also required to be high. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method for brazing an aircraft engine nozzle valve to solve the above-mentioned problems.

[0006] The object of the present invention is achieved through the following technical solutions: A method for brazing an aeroengine nozzle valve comprises the following steps: S1. Processing multiple bosses on the valve base; S2. Pre-place strip solder around the valve base; S3, installing the valve base in the nozzle housing; S4. Weld the gap between the valve base and the nozzle housing.

[0007] The length of the boss is 0.03-0.1 mm.

[0008] The valve base and the nozzle housing are made of high-temperature alloy.

[0009] There is a step S5 between steps S2 and S3, wherein step S5 is to remove the oxide film from the surface to be welded of the nozzle housing and the surface to be welded of the valve base, and then wipe the surface to be welded of the nozzle housing and the surface to be welded of the valve base.

[0010] In step S5, the surface to be welded is wiped with alcohol or acetone.

[0011] The method further comprises step S0, wherein the step S0 is to process the nozzle housing by mechanical processing.

[0012] The beneficial effects of the present invention are: (1) The method of machining the boss on the valve base can accurately control the brazing gap and ensure that there will be no eccentricity between the valve base round tube and the valve housing after assembly, thereby improving the qualified rate of the product; the outer diameter of the boss at the pipe mouth and the inner diameter of the housing oil pipe are assembled with zero clearance to ensure that there will be no eccentricity after assembly. At the same time, the boss area accounts for 1% to 3% of the total brazing area. Even if the boss is not brazed, it will not affect the overall brazing quality (the first type of weld in the brazing standard requires that the unwelded area accounts for no more than 10% of the total area).

[0013] (2) The boss processing method replaces the pre-set foil solder and energy storage positioning welding, which simplifies the process flow and improves work efficiency.

[0014] (3) Pre-setting strip solder further simplifies the process and improves process operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a diagram of the nozzle housing after machining; Figure 2 It is a schematic diagram of a valve base with a boss; Figure 3 is a schematic diagram of the boss structure; Figure 4 is a schematic diagram of boss structure distribution; Figure 5 This is a schematic diagram after pre-setting the solder; Figure 6 This is a schematic diagram of the valve and nozzle structure with tooling; Figure 7 It is a schematic diagram of the flow of brazing material along the gap during brazing; Figure numerals: 1-nozzle housing, 2-valve base, 3-boss, 4-strip solder, 5-tooling. DETAILED DESCRIPTION

[0016] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0017] It is to be noted that the concepts of directions “left”, “right”, “up”, “down”, “front”, “back”, “inside” and “outside” in the following schemes are all relative directions and will not be listed one by one here.

[0018] A method for brazing a nozzle valve of an aero-engine, referring to Figure 1-Figure 7 , including the following steps: A high temperature alloy material is selected and forgings are used to forge the nozzle housing 1 blank and the valve base 2. For those skilled in the art, the high temperature alloy material can also be used to make the nozzle housing 1 blank and the valve base 2 in a 3D printing manner.

[0019] The nozzle housing 1 is processed by mechanical processing, and the processing requirements are based on the corresponding drawing requirements.

[0020] The boss 3 is machined on the valve base 2. The size of the boss 3 is between 0.03 and 0.1 mm. The distribution of the boss 3 is as follows: Figure 4 Of course, for those skilled in the art, the distribution of the bosses 3 is not limited to Figure 4 Four types are shown.

[0021] Mechanical grinding is used to remove the oxide film from the processed nozzle housing 1 to be welded surface and the valve base 2 to be welded surface. For those skilled in the art, sand blowing can also be used to remove the oxide film. After grinding is completed, alcohol is used to wipe the nozzle housing 1 to be welded surface and the valve base 2 to be welded surface. For those skilled in the art, acetone can also be used for wiping.

[0022] A strip-shaped solder 4 is pre-placed around the valve base 2 .

[0023] The valve base 2 is installed into the nozzle housing 1 using the tooling 5 .

[0024] Welding is performed according to the pre-set brazing process parameters. Figure 7 Fill the entire brazing surface in the direction of the arrow.

[0025] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above description or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for brazing an aircraft engine nozzle valve, characterized in that: The following steps are involved: S1. Processing multiple bosses on the valve base; S2. Pre-place strip solder around the valve base; S3, installing the valve base in the nozzle housing; S4, welding the gap between the valve base and the nozzle housing; The outer diameter of the boss and the inner diameter of the nozzle housing oil pipe are assembled with zero clearance.

2. The method for brazing an aircraft engine nozzle valve according to claim 1, characterized in that: The length of the boss is 0.03-0.1 mm.

3. The method for brazing an aircraft engine nozzle valve according to claim 1, characterized in that: The valve base and the nozzle housing are made of high-temperature alloy.

4. The method for brazing an aircraft engine nozzle valve according to claim 1, characterized in that: There is a step S5 between steps S2 and S3, wherein step S5 is to remove the oxide film from the surface to be welded of the nozzle housing and the surface to be welded of the valve base, and then wipe the surface to be welded of the nozzle housing and the surface to be welded of the valve base.

5. The method for brazing an aircraft engine nozzle valve according to claim 4, characterized in that: In step S5, the oxide film is removed by mechanical grinding or sand blasting.

6. The method for brazing an aircraft engine nozzle valve according to claim 4, characterized in that: In step S5, the surface to be welded is wiped with alcohol or acetone.

7. The method for brazing an aircraft engine nozzle valve according to claim 1, characterized in that: The method further comprises step S0, wherein the step S0 is to process the nozzle housing by mechanical processing.

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