Contact protection tooling and laser welding protection method for an aircraft engine fuel nozzle

Abstract

The application discloses a contact protection tool and a laser welding protection method of an aero-engine fuel nozzle, and belongs to the field of nozzle laser welding. The application provides the contact protection tool and the laser welding protection method of the aero-engine fuel nozzle. A step of an inner circle part of the tool is designed to be positioned by using a nozzle end face, so that the step and a thin-walled shell part surrounding a weld seam form an annular groove as a passage of annular flow gas, and an air inlet hole and an air outlet hole of the annular flow gas are left on an outer wall of the tool. Before welding, the tool is connected with the nozzle through the positioning of the inner circle step, and then the annular flow gas is connected to exhaust air in the annular groove. In the welding process, an upper half part of the tool gathers axial flow gas to protect the weld seam and an inner circle part structure of the nozzle, a lower half part of the tool contacts the nozzle to dissipate heat, and air is isolated by using the annular flow gas. The application realizes the technical effect that no oxidation color is generated on surfaces of a weld seam and a heat affected zone after laser welding.

Description

Technical Field

[0001] This invention belongs to the field of nozzle laser welding, and in particular to the laser welding protection method for contact protection tooling and fuel nozzles of aero-engines. Background Technology

[0002] The nozzle rod core and the fuel collector ring shell of a certain aircraft engine are joined by laser welding. The weld depth is approximately 1.2–1.6 mm, the weld circumference diameter is Φ35.4 mm, the weld edge is only 2 mm from the edge of the fuel collector ring shell, and the fuel collector ring shell thickness is approximately 1.2–1 mm. The welding process involves high energy input and poor heat dissipation, making the weld and heat-affected zone highly susceptible to surface oxidation and discoloration after welding. The manufacturing process of aircraft engine fuel nozzles requires high surface quality and does not allow surface oxidation. Therefore, a welding protection method is needed to protect the laser welding process and prevent oxidation of the weld and heat-affected zone after laser welding of the nozzle. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a laser welding protection method for contact protection tooling and fuel nozzles of aero engines.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] A contact protection fixture includes a contact protection fixture body, which is a ring-shaped part, and a step is provided on the inner circular surface of the contact protection fixture body.

[0006] The contact protection fixture body is provided with an air inlet pipe, and an air inlet hole is opened on the contact protection fixture body connected to the air inlet pipe. An air outlet hole is opened on the other side of the contact protection fixture body.

[0007] The air inlet and air outlet are located on the lower side of the uniform step.

[0008] Furthermore, the end face of the main body of the contact protection fixture is chamfered.

[0009] Furthermore, the intake pipe is a copper pipe.

[0010] Furthermore, it also includes a protective cover, which is placed at the center of the contact protection fixture body and is used to fit over the inner circle of the nozzle.

[0011] A method for laser welding protection of an aircraft engine fuel nozzle includes the following steps:

[0012] 1) In the contact protection fixture of the present invention, the nozzle end face is positioned with the step, the step and the thin-walled shell part surrounding the weld form an annular groove as a circulation path, and the space between the nozzle on the other side of the step and the main body 1 of the protection fixture serves as an axial flow channel.

[0013] 2) Pre-circulate the gas, introducing argon gas into the circulation channel through the inlet pipe;

[0014] 3) Introduce axial protective gas through the axial flow channel, then turn on the laser welding machine. The laser passes through the axial flow channel to weld the nozzle according to the predetermined trajectory.

[0015] 4) Stop the circulating air supply after cooling;

[0016] 5) Lift the protective fixture and remove the nozzle parts.

[0017] Furthermore, step (1) also includes covering the nozzle onto the inner circle of the protective cap.

[0018] Furthermore, in step (2), the flow rate of argon gas is 10-12 L / min for more than 30 seconds, and then the flow rate is adjusted to 2-5 L / min.

[0019] Furthermore, in step (3), welding begins after the axial flow gas is pre-circulated for 2 seconds, and the flow rate of the axial flow gas is 16-20 L / min; the axial flow protective gas is argon.

[0020] After the welding process is completed, the axial flow protective gas is shut off after a lag of 3 to 6 seconds.

[0021] Furthermore, in step (4), cooling is performed using water cooling or air cooling.

[0022] Furthermore, in step (4), when the nozzle and tooling temperature cools to room temperature, the supply of circulating gas is stopped after a delay of more than 3 minutes.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention provides a contact protection fixture and a laser welding protection method for aircraft engine fuel nozzles. The inner circular portion of the fixture is designed with steps for positioning using the nozzle end face. These steps, along with the thin-walled shell surrounding the weld, form an annular groove as a passage for circulating gas. The outer wall of the fixture has inlet and outlet holes for the circulating gas. Before welding, the fixture is positioned and connected to the nozzle via the inner circular steps, and then the circulating gas is activated to purge the air from the annular groove. During welding, the upper part of the fixture gathers axial gas to protect the weld and the inner circular structure of the nozzle, while the lower part of the fixture contacts the nozzle for heat dissipation. Simultaneously, the circulating gas isolates the weld from the air. This invention achieves the technical effect of preventing oxidation discoloration on the surface of the weld and heat-affected zone after laser welding.

[0025] Furthermore, a protective cover is added to the inner circle of the nozzle structure. This serves two purposes: firstly, it can help to concentrate the axial flow gas, and secondly, it can protect the structural surface and prevent the metal vapor generated by laser welding from melting the structural surface. Attached Figure Description

[0026] Figure 1 Schematic diagram of the protection scheme;

[0027] Figure 2 This is a schematic diagram of the nozzle structure;

[0028] Figure 3 This is a cross-sectional view of the contact protection tooling of the present invention;

[0029] Figure 4 This is a side view of the contact protection tooling of the present invention;

[0030] Figure 5 This is a side view of the contact protection tooling of the present invention.

[0031] Among them: 1-Contact protection fixture body, 2-Protective cover, 3-Air inlet pipe. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0034] The present invention will now be described in further detail with reference to the accompanying drawings:

[0035] This invention designs a protection method for laser welding of fuel nozzles for aero-engines, manufactures laser welding protection tooling, and formulates protection operation procedures and gas flow parameters. Laser welding protection of the nozzle is achieved through dual-path inert gas coverage and contact heat dissipation. The invention is described in three parts below:

[0036] The first part is the overall design of the protection scheme:

[0037] The principle of the protection scheme designed in this invention is as follows: Figure 1 The protection scheme consists of two parts: inert gas protection and contact protection. Combined with... Figure 2 Let's take a look. Figure 2 This is a simplified diagram of the nozzle structure.

[0038] The inert gas shielding gas uses high-purity argon gas with a purity of over 99.99%, comprising two gas flows: an axial flow parallel to the incident laser beam and an annular flow surrounding the outer surface of the nozzle. Before welding, the annular flow is activated to purge air from the protective tooling groove. After purging, the axial flow is activated and stabilized before laser welding begins. During welding, both shielding gas flows remain activated. After welding, the shielding gas flows remain activated until the welded area cools below its oxidation temperature. Finally, the axial flow is turned off first, followed by the annular flow.

[0039] Contact protection employs a copper annular fixture surrounding the outer surface of the nozzle, with the fixture contacting the nozzle housing. The inner circular portion of the fixture is designed with steps for positioning using the nozzle end face, creating an annular groove with the thin-walled housing surrounding the weld seam, serving as a passage for circulating gas. The outer wall of the fixture has inlet and outlet holes for the circulating gas. Before welding, the fixture is positioned and connected to the nozzle via the inner circular steps, and then the circulating gas is activated to purge the air from the annular groove. During welding, the upper part of the fixture gathers axial gas to protect the weld seam and the inner circular structure of the nozzle, while the lower part of the fixture contacts the nozzle for heat dissipation. The circulating gas acts as a final means of protection, isolating the nozzle from air.

[0040] A copper annular protective cap is added to the inner circle of the nozzle. This serves two purposes: first, it can help to concentrate the axial flow gas; second, it can protect the surface of the structure and prevent the metal vapor generated by laser welding from melting the surface of the structure.

[0041] See Figure 3 , Figure 3 This is a schematic diagram of the contact protection fixture. The inner circle of the contact protection fixture contacts the outer wall of the nozzle housing, and the fixture is positioned using the nozzle end face via a step. The fixture consists of three main components: the contact protection fixture body 1, the protective cover 2, and the air inlet pipe 3. To clearly illustrate the structure and function, the three main components are described below:

[0042] The main body 1 of the contact protection fixture is a ring-shaped component with a stepped through-hole on the inner circular surface and chamfered edges. Its primary function is contact heat dissipation and sealing of the protective gas. The smaller inner hole is designed according to the minimum diameter of the nozzle flange, utilizing gravity to seal the annular groove through the fit between the end face and the flange. Simultaneously, it maximizes the welding space for the laser beam, avoiding interference. The larger inner hole fits with the outer circle of the nozzle housing, sealing the gas. Figure 4 The left side is the air inlet of the annular groove, and the right side is the air outlet of the annular groove.

[0043] Protective cover 2 is a circular cover whose main function is to prevent metal vapor from melting the inner circular structure of the nozzle. After the protective cover 2 is assembled, its outer circular surface, together with the main body 1 of the contact protective fixture, gathers the laser welding axial flow gas to form a gas protection on the weld surface. Its lower edge contacts the nozzle flow channel to close part of the flow channel and prevent the protective gas from flowing out of the flow channel.

[0044] Intake pipe 3 is a section of copper pipe that serves as a connector for introducing gas into the annular groove.

[0045] This invention provides a laser welding protection method for fuel nozzles of aircraft engines, comprising the following steps:

[0046] 1) Kit parts

[0047] Position the nozzle by its outer circle and end face, fit the nozzle together with the protective fixture body 1, and cover it with the protective cover 2;

[0048] 2) Pre-circulation gas

[0049] High-purity argon gas is introduced into the annular groove through vent pipe 3 at a flow rate of 10-12 L / min for at least 30 seconds, after which the flow rate is adjusted to 2-5 L / min.

[0050] 3) Start axial flow gas and welding process

[0051] Turn on the laser welding machine and perform laser welding according to the predetermined trajectory. The axial flow shielding gas is pre-flowed for 2 seconds before welding begins, with a shielding gas flow rate of 16-20 L / min. After the welding process is completed, the axial flow shielding gas is turned off after a 3-6 second delay.

[0052] 4) Cooling

[0053] After cooling with water or simply with air, wait for the nozzle and tooling temperature to drop, and then stop the supply of circulating gas after about 3 minutes.

[0054] 5) Remove the parts

[0055] Lift the protective fixture and remove the nozzle parts.

[0056] The protection method of the present invention is used to protect the laser welding process of aero-engine fuel nozzles and similar structural components, resulting in a high-quality weld surface with no oxidation color on the weld and heat-affected zone surface after laser welding.

[0057] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for laser welding protection of fuel nozzles for aircraft engines, characterized in that, A contact protection fixture is provided, the fixture comprising: The contact protection fixture body (1) is a ring-shaped part, and a step is provided on the inner circular surface of the contact protection fixture body (1). The contact protection fixture body (1) is provided with an air inlet pipe (3), and the contact protection fixture body (1) connected to the air inlet pipe (3) is provided with an air inlet hole, and the other side of the contact protection fixture body (1) is provided with an air outlet hole. The air inlet and air outlet are located on the lower side of the uniform step; The method includes the following steps: 1) The nozzle is fitted into the contact protection fixture, the nozzle end face is positioned with the step, the step and the thin-walled shell part surrounding the weld form an annular groove as a circulation path, and the space between the nozzle on the other side of the step and the main body of the protection fixture (1) serves as an axial flow channel. 2) Pre-circulate the gas and introduce argon gas into the circulation channel through the inlet pipe (3); 3) Introduce axial protective gas through the axial flow channel, then turn on the laser welding machine. The laser passes through the axial flow channel and welds the nozzle according to a predetermined trajectory. 4) Stop the circulating air supply after cooling; 5) Lift the protective fixture and remove the nozzle parts; Step (1) also includes a protective cover (2), which is placed at the center of the contact protection fixture body (1) and is used to fit on the inner circle of the nozzle.

2. The laser welding protection method for aero-engine fuel nozzles according to claim 1, characterized in that, In step (2), the flow rate of argon gas is 10-12 L / min for more than 30 seconds, and then the flow rate is adjusted to 2-5 L / min.

3. The laser welding protection method for aero-engine fuel nozzles according to claim 1, characterized in that, In step (3), welding begins 2 seconds after the axial flow gas is pre-circulated. The flow rate of the axial flow gas is 16-20 L / min. The axial flow shielding gas is argon. After the welding process is completed, the axial flow protective gas is shut off after a lag of 3 to 6 seconds.

4. The laser welding protection method for aero-engine fuel nozzles according to claim 1, characterized in that, In step (4), cooling is performed using water cooling or air cooling.

5. The laser welding protection method for aero-engine fuel nozzles according to claim 1, characterized in that, In step (4), when the nozzle and tooling temperature have cooled to room temperature, the supply of circulating gas is stopped after a delay of more than 3 minutes.

6. The laser welding protection method for aero-engine fuel nozzles according to claim 1, characterized in that, The end face of the contact protection fixture body (1) is chamfered.

7. The laser welding protection method for aero-engine fuel nozzles according to claim 1, characterized in that, The air intake pipe (3) is a copper pipe.

8. The laser welding protection method for aero-engine fuel nozzles according to claim 1, characterized in that, The protective cover (2) is made of copper.

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