A type of C f SiC-clad tube connectors and their induction welding methods and applications

Abstract

This invention belongs to the field of composite material welding technology, and discloses a C f / SiC clad tube connectors and their induction welding methods and applications. The method involves spraying solder onto the surface of the SiC end plug to be welded; after the alcohol on the surface of the SiC end plug has completely evaporated, the SiC end plug is then connected to the C... f / SiC clad tube fitting, with graphite carbon felt for C f The SiC clad tube is wrapped at the welding area to form a prefabricated connector; the prefabricated connector is placed inside an induction coil with 5–50 turns and a frequency of 10–20 kHz, and then placed in a protective atmosphere of Ar or 10. ‑5 ~10 ‑ 1 In a vacuum, an alternating current is passed through an induction coil, and the current is controlled to heat the clad tube to 1400–1600 °C for sintering, thus producing C. f / SiC clad tube connector. This method ensures uniform internal and external temperatures during the cladding tube welding process and achieves rapid connection.

Description

Technical Field

[0001] This invention belongs to the field of composite material welding technology, and more specifically, relates to a C f / SiC clad tube connectors and their induction welding methods and applications. Background Technology

[0002] Currently, induction heating technology is widely used in the welding of SiC clad tubes. The heating element of induction heating welding equipment is generally a graphite ring. An alternating magnetic field is provided by an induction coil, which induces eddy currents on the graphite ring. The energy of these eddy currents is used to heat the graphite ring, and then the heat is transferred to the clad tube to be connected through convective and radiative heat transfer in the atmosphere. However, this rapid welding method has the following two disadvantages: (1) During the welding heating process, the outer surface of the clad tube receives heat first, and then the heat is transferred to the inside, resulting in uneven temperature inside and outside the clad tube. The existence of temperature difference leads to inconsistent thermal expansion between the inside and outside, which may have an adverse effect on the welding effect; (2) Due to the presence of the graphite ring and the insulation material, temperature measurement is inconvenient. Generally, the steady-state temperature of the clad tube is indirectly known by measuring the temperature of the graphite ring. The measured temperature has an error compared with the actual temperature of the clad tube. In view of the above-mentioned disadvantages of induction heating, it is necessary to propose an improved induction heating connection method to make the temperature inside and outside of the SiC clad tube uniform under induction heating, facilitate the placement of the temperature measuring point on the SiC clad tube, and improve the connection performance. Summary of the Invention

[0003] In order to overcome the shortcomings and disadvantages of the existing technology, the purpose of this invention is to provide a C f An induction welding method for SiC clad tube connectors is described, which ensures uniform internal and external temperatures during the cladding tube welding process and achieves rapid connection.

[0004] Another object of the present invention is to provide C obtained by the above-described induction welding method. f / SiC clad tube connector.

[0005] Another object of the present invention is to provide the above-mentioned C f Applications of SiC-clad tube connectors.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A type of C f The induction welding method for SiC clad tube connectors includes the following steps:

[0008] S1. Spray solder onto the surface of the SiC end plug to be soldered. The solder is SiC, Al2O3 and Re2O3 mixed with alcohol, where Re2O3 is Ce2O3 or Y2O3; SiC and SiO2 mixed with alcohol; CaO, Al2O3, MgO and SiO2 mixed with alcohol.

[0009] S2. After the alcohol on the surface of the SiC end plug has completely evaporated, connect the SiC end plug to the C... f / SiC clad tube fitting, with graphite carbon felt for C f The welding area of ​​the SiC clad tube is wrapped to form a prefabricated connector;

[0010] S3. Place the prefabricated connector inside an induction coil with 5 to 50 turns and a frequency of 10 to 20 kHz, in a protective atmosphere of Ar or 10⁻⁵ to 10⁻⁵ kHz. -1 In a vacuum, an alternating current is passed through an induction coil, and the current is controlled to heat the clad tube to 1400–1600 °C for sintering, thus producing C. f / SiC clad tube connector.

[0011] Preferably, in step S1, the mass ratio of SiC, Al2O3 and Re2O3 mixed in alcohol is (3-8):1:1; the mass ratio of SiC and SiO2 mixed in alcohol is (1-3):1; and the mass ratio of CaO, Al2O3, MgO and SiO2 mixed in alcohol is (1-8):1:1:1.

[0012] Preferably, the SiC end plug of the part to be welded is pressureless sintered silicon carbide (PLS-SiC), chemical vapor deposition silicon carbide (CVD-SiC), or reaction sintered silicon carbide (RB-SiC).

[0013] Preferably, the C in step S2 f The outer diameter of the SiC clad tube is 9–12 mm, and the inner diameter is 6–8 mm. f The length of the SiC clad tube is 16–100 mm.

[0014] Preferably, the heating rate in step S3 is 50–200 °C / min, and the sintering time is 1–60 min.

[0015] A type of C f / SiC clad tube connector, the C f The SiC clad tube connector is prepared by the method described above.

[0016] Preferably, the C f The SiC cladding tube connector has a boss-type interlocking structure with a push-out force of 2000–4000 N.

[0017] The C mentioned f Applications of SiC clad tube connectors in aerospace, military, and nuclear energy fields.

[0018] Typically, when carbon fibers are introduced into a SiC ceramic matrix, it becomes C. f / SiC composite materials, while carbon fiber has good electrical conductivity, similar to graphite rings, and may be used as a heating element for induction heating, thereby transmitting the heat through C f / SiC clad tubes achieve welding through self-heating. This invention, however, uses an alternating magnetic field generated by the alternating current of an induction coil to directly act on the C... f The carbon fibers in the SiC clad tube induce eddy currents within the carbon fibers. Since heat flows from the inside out, C... f / SiC clad tubes exhibit uniform temperature, enabling internal heating C f / SiC clad tube, completing C f High-efficiency welding of SiC clad tubes. Therefore, welded joints with high mechanical properties and uniform weld layer can be obtained.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This invention uses induction welding to obtain C f The SiC clad tube connector features a highly simplified induction heating device, eliminating the need for a graphite ring as the heating element, thus improving thermal efficiency and enabling rapid welding of SiC clad tubes even at low power.

[0021] 2. This invention achieves C through self-heating. f / SiC clad tube welding: the temperature of each layer of material is similar, the thermal expansion rate is consistent, and the welding thermal stress is small.

[0022] 3. The C prepared by this invention f / SiC clad tube connectors have high pull-out strength (2000~4000N) and the welded joint connection layer is uniform. Attached Figure Description

[0023] Figure 1 The present invention uses induction welding to obtain C f A cross-sectional schematic diagram of the / SiC clad tube connector.

[0024] Figure 2 For the present invention C f / A schematic diagram of the microscopic eddy currents generated by carbon fibers in a SiC clad tube under the action of an alternating magnetic field. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments, but these should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0026] Figure 1 The present invention uses induction welding to obtain C f A cross-sectional schematic diagram of the / SiC clad tube connector. Where 1 represents C. f / SiC clad tube (composition: 6 is a SiC ceramic layer, 7 is a carbon fiber layer C) f ), 2 is the induction coil, 3 is the graphite carbon felt, 4 is the SiC end plug, and 5 is the solder layer. From Figure 1 As can be seen from this, the alternating current in the induction coil is at C f An alternating magnetic field is generated along the central axis of the SiC clad tube, causing C f The carbon fiber layer in the SiC clad tube induces heating eddies. Figure 2 For the present invention C f A schematic diagram of the microscopic eddy currents generated by carbon fibers in a SiC-clad tube under an alternating magnetic field. Figure 2 As can be seen from this, C is achieved by using induction. f / SiC clad tube welding, through the alternating magnetic field generated by the alternating current of the induction coil, directly acts on C f The carbon fibers in the SiC clad tube induce eddy currents within the carbon fibers, thereby heating the C from the inside. f / SiC clad tube, completing C f High-efficiency welding of SiC clad tubes is achieved because the heat flows from the inside out. f The SiC cladding tube has a uniform temperature. Therefore, a welded joint with high mechanical properties and a uniform weld layer can be obtained.

[0027] Example 1

[0028] 1. A solder is prepared by mixing SiC, Al2O3 and Ce2O3 in a mass ratio of 8:1:1 with anhydrous ethanol at a concentration of 99.99%. The solder is then sprayed onto the surface of the pressureless sintered silicon carbide (PLS-SiC) end plug of the part to be soldered using a spraying device.

[0029] 2. After the alcohol on the surface of the SiC end plug has completely evaporated, connect the SiC end plug to the C... f / SiC clad tube (outer diameter 10mm) fitting, with graphite carbon felt for C f The SiC clad tube welding area is wrapped with a thickness of 1.5mm to form a prefabricated connector;

[0030] 3. Place the prefabricated connector inside an induction coil with 5 turns and a frequency of 13 kHz. In an Ar atmosphere of 0.1 MPa, control the current in the induction coil to heat the cladding tube to 1400℃ at a rate of 100℃ / min, then hold it at that temperature for 10 min. After symmetrical cooling, a boss-shaped C is obtained. f / SiC clad tube connector.

[0031] The C prepared in this embodiment was according to ASTM C1862 standard. f The SiC clad tube connector underwent an ejection force test, achieving a room temperature ejection force of 2494 N. Observation of the connector cross-section revealed a uniform and consistent connecting layer, indicating that the boss-type C-shaped connector... f SiC clad tube connectors have excellent mechanical properties and can be widely used in aerospace, military and nuclear energy fields.

[0032] Example 2

[0033] 1. A solder is prepared by mixing SiC and SiO2 in a mass ratio of 1:1 with 99.99% anhydrous ethanol. The solder is then sprayed onto the surface of the reaction-bonded silicon carbide (RB-SiC) end plug to be soldered using a spraying device.

[0034] 2. After the alcohol on the surface of the SiC end plug has completely evaporated, connect the SiC end plug to the C... f The SiC clad tube (outer diameter 10mm) is fitted together, and the welding part of the SiC clad tube is wrapped with graphite carbon felt with a wrapping thickness of 1.8mm to form a prefabricated connector.

[0035] 3. Place the prefabricated connector inside an induction coil with 5 turns and a frequency of 13kHz, and run it for 10 seconds. -1 In a vacuum, the current in the induction coil is controlled to heat the cladding tube to 1450℃ at a rate of 80℃ / min, then held at that temperature for 15min, and then cooled symmetrically to obtain a boss-shaped C-shaped tube. f / SiC clad tube connector.

[0036] The C prepared in this embodiment was according to ASTM C1862 standard. f The SiC clad tube connector underwent an ejection force test, achieving a room temperature ejection force of 2861 N. Observation of the connector cross-section revealed a uniform and consistent connecting layer, indicating that the boss-type C-shaped connector... f SiC clad tube connectors have excellent mechanical properties and can be widely used in aerospace, military and nuclear energy fields.

[0037] Example 3

[0038] 1. A solder is prepared by mixing SiC, Al2O3 and Y2O3 in a mass ratio of 8:1:1 with 99.99% anhydrous ethanol. The solder is then sprayed onto the surface of the chemical vapor deposition silicon carbide (CVD-SiC) end plug of the workpiece to be soldered using a spraying device.

[0039] 2. After the alcohol on the surface of the SiC end plug has completely evaporated, connect the SiC end plug to the C... f / SiC clad tube (outer diameter 10mm) fitting, using graphite carbon felt to bond C f The SiC clad tube welding area is wrapped with a thickness of 1.2mm to form a prefabricated connector;

[0040] 3. Place the prefabricated connector inside an induction coil with 5 turns and a frequency of 13kHz. In a protective atmosphere or vacuum, enable the induction coil and control the current in the induction coil to heat the casing tube to 1500℃ at a rate of 100℃ / min. Then hold at that temperature for 5 minutes and cool symmetrically to obtain a boss-shaped C. f / SiC clad tube connector.

[0041] The C prepared in this embodiment was according to ASTM C1862 standard. f The SiC clad tube connector underwent an ejection force test, achieving a room temperature ejection force of 3018 N. Observation of the connector cross-section revealed a uniform and consistent connecting layer, indicating that the boss-type C-shaped connector... f SiC clad tube connectors have excellent mechanical properties and can be widely used in aerospace, military and nuclear energy fields.

[0042] Example 4

[0043] 1. Prepare a solder by mixing CaO, Al2O3, MgO and SiO2 in alcohol at a mass ratio of 8:1:1:1. Apply the solder to the surface of the PLS-SiC end plug to be soldered using a spraying device.

[0044] 2. After the alcohol on the surface of the SiC end plug has completely evaporated, connect the SiC end plug to the C... f / SiC clad tube fitting (outer diameter 10mm), using graphite carbon felt to bond C f The SiC clad tube welding area is wrapped with a thickness of 2mm to form a prefabricated connector.

[0045] 3. Place the prefabricated connector inside an induction coil with 5 turns and a frequency of 13kHz. In a protective atmosphere or vacuum, enable the induction coil and control the current in the induction coil to heat the cladding tube to 1500℃ at a rate of 150℃ / min for sintering. Then hold at that temperature for 8 minutes, and after symmetrical cooling, obtain a boss-shaped C. f / SiC clad tube connector.

[0046] The C prepared in this embodiment was according to ASTM C1862 standard. f The SiC clad tube connector underwent an ejection force test, with a room temperature ejection force of 2219 N. Observation of the connector cross-section revealed a uniform and consistent connecting layer, indicating that the boss-type C-shaped connector... f SiC clad tube connectors have excellent mechanical properties and can be widely used in aerospace, military and nuclear energy fields.

[0047] Example 5

[0048] 1. Prepare a solder by mixing SiC, Al2O3 and Y2O3 in alcohol at a mass ratio of 3:1:1, and then spray the solder onto the surface of the PLS-SiC end plug to be soldered using a spraying device.

[0049] 2. After the alcohol on the surface of the SiC end plug has completely evaporated, connect the SiC end plug to the C... f / SiC clad tube (outer diameter 10mm) fitting, using graphite carbon felt to bond C f The SiC clad tube welding area is wrapped with a thickness of 1.2mm to form a prefabricated connector;

[0050] 3. Place the prefabricated connector inside an induction coil with 5 turns and a frequency of 13kHz. In a protective atmosphere or vacuum, enable the induction coil and control the current in the induction coil to heat the cladding tube to 1500℃ at a rate of 100℃ / min for sintering. Then hold at that temperature for 5 minutes, and after symmetrical cooling, obtain a boss-shaped C. f / SiC clad tube connector.

[0051] The C prepared in this embodiment was according to ASTM C1862 standard. f The SiC clad tube connector underwent an ejection force test, yielding 2932 N at room temperature. Observation of the connector cross-section revealed a uniform and consistent connecting layer, indicating that the boss-type C-shaped connector... f SiC clad tube connectors have excellent mechanical properties and can be widely used in aerospace, military and nuclear energy fields.

[0052] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A type of C f The induction welding method for SiC clad tube connectors is characterized by... Includes the following steps: S1. Apply solder to the surface of the SiC end plug to be soldered. The solder is a mixture of SiC, Al2O3, and Re2O3 mixed with alcohol, wherein Re2O3 is Ce2O3 or Y2O3, SiC and SiO2 mixed with alcohol, and CaO, Al2O3, MgO, and SiO2 mixed with alcohol. The mass ratio of SiC, Al2O3, and Re2O3 mixed with alcohol is (3~8):1:1; the mass ratio of SiC and SiO2 mixed with alcohol is (1~3):1; and the mass ratio of CaO, Al2O3, MgO, and SiO2 mixed with alcohol is (1~8):1:1:

1. S2. After the alcohol on the surface of the SiC end plug has completely evaporated, connect the SiC end plug to the C... f / SiC clad tube fitting, with graphite carbon felt for C f The SiC clad tube welding area is wrapped to form a prefabricated connector; S3. Place the prefabricated connector inside an induction coil with 5-50 turns and a frequency of 10-20 kHz, and place it in a protective atmosphere of Ar or 10 kHz. -5 ~10 -1 In a vacuum, alternating current is passed through an induction coil, and the current is controlled to heat the clad tube to 1400~1600 ℃ for sintering, thus producing C. f / SiC clad tube connector; the alternating magnetic field generated by the alternating current of the induction coil directly acts on C f The carbon fibers in the SiC clad tube induce eddy currents within the carbon fibers. Since heat flows from the inside out, C... f / SiC clad tubes exhibit uniform temperature, enabling internal heating C f / SiC clad tube.

2. The C according to claim 1 f The induction welding method for SiC clad tube connectors is characterized by... The SiC end plug of the workpiece to be welded in step S1 is pressureless sintered silicon carbide, chemical vapor deposition silicon carbide, or reaction sintered silicon carbide.

3. The C according to claim 1 f The induction welding method for SiC clad tube connectors is characterized by... C in step S2 f The outer diameter of the SiC clad tube is 9~12 mm, and the inner diameter is 6~8 mm. f The length of the SiC clad tube is 16~100 mm.

4. The C according to claim 1 f The induction welding method for SiC clad tube connectors is characterized by... The thickness of the package described in step S2 is 1~2 mm.

5. The C according to claim 1 f The induction welding method for SiC clad tube connectors is characterized by... The heating rate in step S3 is 50~200 ℃ / min, and the sintering time is 1~60 min.

6. A type of C f / SiC clad tube connector, characterized in that The C f The SiC clad tube connector is prepared by the method described in any one of claims 1 to 5.

7. C according to claim 6 f / SiC clad tube connector, characterized in that The C f The SiC cladding tube connector has a boss-type interlocking structure with a push-out force of 2000~4000 N.

8. The C according to claim 6 or 7 f Applications of SiC clad tube connectors in aerospace, military, and nuclear energy fields.

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