A brazing method for sealing structure of pulse engine output end

Abstract

The invention discloses a brazing method for a pulse engine output end sealing structure, comprising: placing a brazing material in a groove of a pulse engine housing; placing an ultra-thin metal foil in the groove of the pulse engine housing to press the brazing material; pressing the metal foil with a pressing tool to fit it with the brazing material, and placing the whole into a brazing furnace; turning on the brazing furnace, setting the brazing temperature and the brazing insulation time, and cooling to room temperature after the brazing is completed; taking out the pulse engine, cleaning the brazing part, removing the residual brazing agent, coating a layer of three-proof protective agent on the brazing part and the foil surface, and curing at room temperature. Compared with the traditional output end foil, the present invention is thinner, the bursting pressure of the sealing structure is lower, and the sealing performance is stable and the long-term storage performance is good.

Description

Technical Field

[0001] The invention relates to a brazing method for a sealing structure of a pulse engine output end, which is suitable for sealing connection of a small pulse engine output end and belongs to the field of pyrotechnics. Background Art

[0002] Aerospace pyrotechnics are core components for the ignition, separation, and attitude adjustment of carrier models and defense projects, and are widely used in aviation, aerospace, ships, weapons, and other fields. The agents in pyrotechnics need to be in a well-sealed state during long-term storage. Therefore, strict requirements are placed on the sealing of the output end. The output end of a small pulse engine is sealed with a curling + gluing structure, which has certain shortcomings:

[0003] 1) In order to extend the life cycle of the system, the model requires that the storage period of the pulse engine be increased to (17 to 20) years. The adhesive is prone to aging failure after long-term storage, which reduces the sealing performance of the output end of the pyrotechnics. After moisture enters, the temperature-humidity alternating load can easily cause the pyrotechnics to fail, affecting the storage life of the product;

[0004] 2) The existing adhesive sealing method has low strength. After the pyrotechnics are stored in extreme environments, the adhesive ages rapidly and the connection strength is further reduced, making it difficult to meet the requirements of the use environment.

[0005] 3) Adhesive structures require a long curing time (e.g. HXJ-14 glue requires 24 hours of curing, and low-temperature epoxy glue requires 7 days of curing). Other operations cannot be performed during the curing process, which prolongs the product production cycle and affects the delivery schedule.

[0006] Therefore, it is proposed to study the brazing sealing of the output end of the pulse engine to improve the storage sealing performance and production efficiency of the product.

[0007] The output end of the pulse engine is a nozzle with a diameter of about 10mm. The diaphragm needs to be opened within an explosion pressure of 5MPa. The typical metal foil for sealing connection is about (0.03~0.05)mm thick. The current laser welding process will directly ablate the diaphragm and cannot achieve a sealed connection.

[0008] At present, there is no report on the welding and sealing of ultra-thin metal foil ((0.03~0.05)mm thick) and pulse engine. Summary of the invention

[0009] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide a brazing method for the sealing structure of the output end of a pulse engine, to overcome the problem of poor long-term storage reliability of the sealing structure of the curled edge and glue-coated output end of the pulse engine, to achieve a welding and sealing connection between the output end of the pulse engine and the ultra-thin foil, and at the same time to use a material with better weldability as the output end foil, to avoid the problem of poor product appearance or unstable sealing caused by base material corrosion caused by active brazing flux during the brazing process.

[0010] The technical solution of the present invention is: a brazing method for a pulse engine output end sealing structure, comprising:

[0011] Placing the brazing material in the groove of the pulse engine housing;

[0012] Place the ultra-thin metal foil into the groove of the pulse engine housing to press the brazing material;

[0013] Use a pressing tool to press the metal foil to make it fit with the brazing material, and put the whole into the brazing furnace;

[0014] Turn on the brazing furnace, set the brazing temperature and brazing holding time, and cool to room temperature after brazing is completed;

[0015] Take out the pulse engine, clean the brazing area, remove the residual brazing flux, apply a layer of three-proof protective agent on the brazing area and the foil surface, and cure it at room temperature.

[0016] Preferably, the solder is any one of the following:

[0017] Sn63Pb37, Sn96.5Ag3Cu0.5, SnSb5.

[0018] Preferably, the brazing temperature is: 250±5°C.

[0019] Preferably, the brazing holding time is 5±2 min.

[0020] Preferably, the ultra-thin metal foil has a thickness of 0.03 mm to 0.05 mm and can be made of any of the following materials:

[0021] Zn, Ag72Cu28, Pb95Ag5, Ag, Cu, Ni.

[0022] Preferably, when the metal foil is pressed by the pressing tool, the pressing pressure is 0.2 MPa to 0.5 MPa.

[0023] Preferably, the triple-proof protective agent is DBSF-6102, and the curing time at room temperature is 2h to 3h.

[0024] Preferably, the solder is in a ring-shaped solder or a paste-shaped solder.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) The thickness of the weldable and sealed metal foil of the present invention is (0.03-0.05) mm, which is thinner than the conventional output-end foil and has a lower bursting pressure of the sealing structure;

[0027] (2) The present invention adopts brazing sealing, which can withstand more severe environmental and mechanical conditions, has stable sealing performance and good long-term storage performance;

[0028] (3) The present invention uses materials with good brazing properties as the output end foil (Zn, Ag72Cu28, Pb95Ag5, Ag, Cu, Ni, etc.), and can directly use solder with low-activity flux, and batch welding can be completed in the low-temperature state of the atmospheric environment, and the appearance after welding is good;

[0029] (4) The present invention adopts materials (Zn, Ag72Cu28, Pb95Ag5, Ag, Cu, Ni) as the output end foil. The material has good rigidity and toughness, and the melting point is within 780°C, which is close to the melting point of traditional aluminum foil as the output end material, and can be easily directly burned and exploded by gunpowder. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the sealing structure of the present invention.

[0031] The accompanying drawings are marked as: pulse engine casing 1, solder 2, and ultra-thin metal foil 3. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is: a method for brazing a sealing structure at the output end of a pulse engine: mainly comprising a pulse engine casing, brazing material (Sn63Pb37, Sn96.5Ag3Cu0.5, SnSb5), and ultra-thin metal foil ((Zn, Ag72Cu28, Pb95Ag5, Ag, Cu, Ni), with a thickness of (0.03-0.05) mm).

[0033] The preparation of the sealing structure mainly includes the following steps:

[0034] 1) Place the solder with low-activity flux in the groove of the pulse engine housing;

[0035] 2) Place the ultra-thin metal foil into the groove of the pulse engine housing to press the solder;

[0036] 3) Press the metal foil with a pressing tool and put the whole into the brazing furnace;

[0037] 4) Turn on the brazing furnace, set the brazing temperature to (250±5)℃, and the brazing holding time to (5±2)min. After brazing, cool to room temperature;

[0038] 5) Take out the pulse engine, clean the brazing area, remove the residual brazing flux, apply a thin layer of triple-proof protective agent (DBSF-6102) on the brazing area and the foil surface, and cure at room temperature for (2-3) hours.

[0039] like Figure 1 As shown, a method for brazing a sealing structure at an output end of a pulse engine of the present invention comprises a pulse engine housing 1, a brazing material 2, and an ultra-thin metal foil 3.

[0040] The present invention implements the steps as follows:

[0041] 1. Place solder 2 (Sn63Pb37, Sn96.5Ag3Cu0.5, SnSb5) containing low-activity flux in the groove of the pulse engine housing 1. The solder 2 is in the form of a ring solder or a paste solder.

[0042] 2. Place ultra-thin metal foil (Zn, Ag72Cu28, Pb95Ag5, Ag, Cu, Ni, thickness (0.03-0.05) mm) in the groove of the pulse engine housing 1 and press the solder 2;

[0043] 3. Use a pressing tool to press the ultra-thin metal foil to make it fit well with the brazing material layer. The pressure is (0.2-0.5) MPa, and the whole is placed in the brazing furnace;

[0044] 4. Turn on the brazing furnace, set the brazing temperature to (250±5)℃, and the brazing holding time to (5±2)min. After brazing, cool with air or wind to room temperature.

[0045] 5. Take out the pulse engine, clean the brazing area, remove the residual brazing flux, apply a thin layer of triple-proof protective agent (DBSF-6102) on the brazing area and the foil surface, and cure it at room temperature for (2-3) hours.

[0046] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims

1. A method for brazing a sealing structure at the output end of a pulse engine, characterized in that include: Placing the brazing material in the groove of the pulse engine housing; Place the ultra-thin metal foil into the groove of the pulse engine housing to press the brazing material; Use a pressing tool to press the metal foil to make it fit with the brazing material, and put the whole into the brazing furnace; Turn on the brazing furnace, set the brazing temperature and brazing holding time, and cool to room temperature after brazing is completed; Take out the pulse engine, clean the brazing area, remove the residual brazing flux, apply a layer of three-proof protective agent on the brazing area and the foil surface, and cure it at room temperature.

2. A method for brazing a sealing structure at an output end of a pulse engine according to claim 1, characterized in that: The solder can be any of the following: Sn63Pb37, Sn96.5Ag3Cu0.5, SnSb5.

3. A method for brazing a sealing structure at an output end of a pulse engine according to claim 1, characterized in that: Brazing temperature: 250±5℃.

4. A method for brazing a sealing structure at an output end of a pulse engine according to claim 1, characterized in that: The brazing holding time is 5±2min.

5. The brazing method of the pulse engine output end sealing structure according to claim 1, characterized in that: The thickness of ultra-thin metal foil is 0.03mm~0.05mm, and can be made of any of the following materials: Zn, Ag72Cu28, Pb95Ag5, Ag, Cu, Ni.

6. A method for brazing a sealing structure at an output end of a pulse engine according to claim 1, characterized in that: When the metal foil is pressed by a pressing tool, the pressure applied is 0.2MPa~0.5MPa.

7. A method for brazing a sealing structure at an output end of a pulse engine according to claim 1, characterized in that: The triple-proof protective agent uses DBSF-6102, and the curing time at room temperature is 2h to 3h.

8. A method for brazing a sealing structure at an output end of a pulse engine according to claim 1, characterized in that: The solder state is ring solder or paste solder.

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