An alloy transition bushing and brazing method for the socket structure brazing of a Y-TZP ceramic furnace body and a metal component

Abstract

An alloy transition bushing and brazing method for the socket structure brazing of a Y-TZP ceramic furnace body and a metal component, which relates to an alloy transition bushing for brazing and its application. In order to solve the problems of large residual stress existing in the direct brazing of the existing Y-TZP ceramic furnace body with copper wire, K-type thermocouple wire and 316L gas pipe main pipe, and the low mechanical properties, sealing performance and thermal shock resistance of the brazed joint. The present invention uses a copper wire transition bushing, a thermocouple transition bushing and a gas pipe connection transition bushing for the brazing transition between the metal component and the Y-TZP ceramic furnace body. The transition bushing can effectively relieve the residual stress between the Y-TZP ceramic furnace body of the induction heating furnace and the copper wire, thermocouple and gas pipe main pipe. The corrosion phenomenon of the metal base material in the socket joint is inhibited, and the mechanical properties, sealing performance and thermal shock resistance of the joint are all significantly improved.

Description

Technical Field

[0001] The present invention relates to an alloy transition bushing for brazing and its application. Background Art

[0002] Induction heating furnaces have been used in the aerospace field. For example, the volatile preparation unit of the lunar soil volatile analyzer in aerospace uses an induction heating furnace for measuring the volatiles and their isotope contents in lunar soil. It plays an important role in heating lunar soil and preparing volatiles.

[0003] The functional parts of the induction heating furnace for aerospace consist of a Y-TZP ceramic (yttria-stabilized tetragonal zirconia polycrystalline ceramic) furnace body, an oxygen-free copper induction coil (copper wire), a K-type thermocouple (Ni-based alloy), a conduit, etc. After the volatiles are prepared, the induction heating furnace needs to maintain airtightness to prevent the leakage of volatile components. Therefore, it is necessary to ensure the airtightness of the connection between the Y-TZP ceramic furnace body and other metal components. Considering the differences in the weldability between ceramics and metals, as well as the temperature adaptability, technical requirements, and special service conditions of aerospace product connections, the connection process between the Y-TZP ceramic furnace body and other metal components is mainly the brazing process, and generally, AgCuTi active brazing filler metal is selected.

[0004] However, there are significant differences in the physical and chemical properties between Y-TZP ceramics and metals such as copper and Ni-based alloys, especially in the linear expansion coefficient. Moreover, the AgCuTi brazing filler metal severely corrodes the copper wire, and the copper wire is extremely easy to be melted; and directly brazing the Y-TZP ceramic furnace body with the copper wire, the K-type thermocouple wire, and the 316L gas pipe main pipe will generate relatively large residual stresses, resulting in a reduction in the mechanical properties, sealing performance, and thermal shock resistance of the joint. Summary of the Invention

[0005] In order to solve the problems of relatively large residual stresses existing in the direct brazing of the existing Y-TZP ceramic furnace body with the copper wire, the K-type thermocouple wire, and the 316L gas pipe main pipe, and the low mechanical properties, sealing performance, and thermal shock resistance of the brazed joint, the present invention provides an alloy transition bushing for brazing the socket joint structure of the Y-TZP ceramic furnace body and metal components and a brazing method.

[0006] The alloy transition bushing for brazing the socket structure of the Y-TZP ceramic furnace body and the metal component of the present invention includes a copper wire transition bushing (1), a thermocouple transition bushing (2), and an air duct connection pipe transition bushing (3); the copper wire transition bushing (1) consists of a copper wire sleeve (11) and a copper wire transition bushing flange (12), and the copper wire transition bushing flange (12) is arranged at one end of the copper wire sleeve (11); the thermocouple transition bushing (2) consists of a thermocouple sleeve (21) and a thermocouple transition bushing flange (22), and the thermocouple transition bushing flange (22) is arranged at one end of the thermocouple sleeve (21); the air duct connection pipe transition bushing (3) is composed of an air duct connection pipe connecting sleeve (31) and an air duct connection pipe transition bushing flange (32), and the air duct connection pipe transition bushing flange (32) is arranged in the middle of the outer surface of the air duct connection pipe connecting sleeve (31).

[0007] The method for brazing the Y-TZP ceramic furnace body and the metal component by using the alloy transition bushing for brazing the socket structure of the Y-TZP ceramic furnace body and the metal component of the present invention is carried out according to the following steps:

[0008] Step 1: Use a vernier caliper and a plug gauge to measure the fit clearance between the welding hole and the transition bushing, and the fit clearance between the transition bushing and the metal component to meet the brazing requirements;

[0009] The welding holes are the copper wire welding hole on the Y-TZP ceramic furnace body, the thermocouple welding hole on the Y-TZP ceramic furnace body, and the air duct welding hole on the Y-TZP ceramic furnace body;

[0010] The metal components are copper wires and thermocouples;

[0011] The transition bushings are the copper wire transition bushing (1), the thermocouple transition bushing (2), and the air duct connection pipe transition bushing (3);

[0012] Step 2: Cut the AgCuTi filler metal foil strip into a parallelogram and a circular ring;

[0013] Step 3: Grind the cut AgCuTi filler metal foil strip with 400# sandpaper to remove the dense oxide skin on its surface, and then clean and dry it;

[0014] Step 4: Wrap the cleaned parallelogram AgCuTi filler metal foil strip on the outer surface of the copper wire sleeve (11) of the copper wire transition bushing (1), the outer surface of the thermocouple sleeve (21) of the thermocouple transition bushing (2), and the outer surface of the air duct connection pipe connecting sleeve (31) of the air duct connection pipe transition bushing (3);

[0015] Step Five: Place the copper wire transition bushing (1) wrapped with AgCuTi solder foil tape into the copper wire welding hole, and place an annular AgCuTi solder foil tape between the copper wire transition bushing flange (12) in the copper wire transition bushing (1) and the Y-TZP ceramic furnace body; place the thermocouple transition bushing (2) wrapped with AgCuTi solder foil tape into the thermocouple welding hole, and place an annular AgCuTi solder foil tape between the thermocouple transition bushing flange (22) in the thermocouple transition bushing (2) and the Y-TZP ceramic furnace body; place the gas pipe connection transition bushing (3) wrapped with AgCuTi solder foil tape into the gas pipe welding hole, and place an annular AgCuTi solder foil tape between the gas pipe connection transition bushing flange (32) in the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body;

[0016] Step Six: Clean and dry the copper wire welding hole on the Y-TZP ceramic furnace body, the thermocouple welding hole on the Y-TZP ceramic furnace body, the gas pipe welding hole on the Y-TZP ceramic furnace body, and the metal components;

[0017] Step Seven: Apply AgCuTi solder paste between the circumferential surface of the copper wire transition bushing flange (12) in the copper wire transition bushing (1) and the Y-TZP ceramic furnace body, and apply AgCuTi solder paste on the gap between the lower end surface of the copper wire transition bushing flange (12) and the lower end surface of the copper wire welding hole;

[0018] Place the thermocouple into the thermocouple sleeve (21) of the thermocouple transition bushing (2), apply AgCuTi solder paste between the circumferential surface of the thermocouple and the upper surface of the thermocouple transition bushing flange (22), apply AgCuTi solder paste between the circumferential surface of the thermocouple transition bushing flange (22) and the Y-TZP ceramic furnace body, and apply AgCuTi solder paste on the inner wall of the thermocouple welding hole on the lower end surface of the thermocouple sleeve (21) and the Y-TZP ceramic furnace body;

[0019] Apply AgCuTi solder paste between the circumferential surface of the gas pipe connection transition bushing flange (32) of the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body, and apply AgCuTi solder paste on the gap between the lower end surface of the gas pipe connection sleeve (31) of the gas pipe connection transition bushing (3) and the lower end surface of the gas pipe welding hole;

[0020] Step Eight: Fix the copper wire transition bushing (1), the thermocouple transition bushing (2), and the gas pipe connection transition bushing (3) through the tooling fixture to complete the pre-welding assembly work;

[0021] Step Nine: Place the Y-TZP ceramic furnace body into the vacuum furnace for brazing;

[0022] Step 10: Take out the Y-TZP ceramic furnace body, polish the inner hole of the copper wire sleeve (11) in the copper wire transition bushing (1) and the copper wire to be welded, brush them with acetone, and then dry them;

[0023] Step 11: placing the copper wire in the inner hole of the copper wire sleeve (11) in the copper wire transition bushing (1), and applying paste-like AgCuInSn solder between the upper end surface of the copper wire sleeve (11) in the copper wire transition bushing (1) and the circumferential surface of the copper wire;

[0024] Step 12: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing.

[0025] The principles and beneficial effects of the present invention are:

[0026] 1. The present invention uses a copper wire transition bushing (1), a thermocouple transition bushing (2) and a gas pipe transition bushing (3) for brazing transition between a metal component and a Y-TZP ceramic furnace body. The transition bushing can effectively relieve the residual stress between the Y-TZP ceramic furnace body of the induction heating furnace and the copper wire, the thermocouple and the gas pipe main pipe. Moreover, the weld will not crack and fail after being assessed in a mechanical environment (conditions are 18g acceleration test, 12g sinusoidal vibration test, 15.5g random vibration test and 1800g impact test) and a temperature environment (-195℃~195℃ thermal cycle test), thus meeting the application requirements of aerospace. At the same time, the present invention takes advantage of the easy machining performance of Kovar alloy, uses Kovar alloy to process into a transition bushing structure for brazing ceramic and metal socket structures, and utilizes the characteristics of Kovar alloy with moderate thermal expansion coefficient and difficulty in corrosion to greatly alleviate the post-weld residual thermal stress caused by the difference in thermal expansion coefficient of the parent materials on both sides during the brazing process of the socket structure ceramic and metal, and the corrosion phenomenon of the metal parent material in the socket joint is suppressed, and the mechanical properties, sealing properties and thermal shock resistance of the joint are significantly improved.

[0027] 2. The material of the transition bushing used in the present invention is 4J50 Kovar alloy, which reacts well with the AgCuTi solder used for welding ceramics. Therefore, the shear strength of the brazed joint between the transition bushing and the Y-TZP ceramic is extremely high, and the joint strength of the flat joint and the socket joint reaches 80MPa.

[0028] 3. The transition bushing used in the present invention effectively avoids the corrosion of the AgCuTi solder on the copper wire and protects the shape and size of the oxygen-free copper wire.

[0029] 4. The present invention pre-bends the solder foil into shape and places it in the weld, which greatly promotes the flow and filling of liquid active solder into the metal ceramic weld during brazing, making the induction heating furnace weld excellent in air tightness, and the induction heating furnace weld leakage rate is <5×10 -13 Pa·m 3 / s. It avoids the situation that due to the too small diameters of the copper wire and the K-type thermocouple wire, the depth-diameter ratio of the corresponding welding holes on the ceramic furnace body is too large. Due to the difficult operation, the filler metal cannot be placed in advance, the filler metal cannot be completely filled, and the airtightness of the induction heating furnace is poor.

[0030] 5. In the present invention, the transition bushing is provided with a positioning platform (flange), which is used in cooperation with the brazing fixture. During welding, the weld gap can be ensured to remain unchanged, which is beneficial to the smooth flow and filling of the filler metal and the dimensional accuracy of the induction heating furnace. Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of the copper wire transition bushing (1), the thermocouple transition bushing (2) and the gas pipe connection transition bushing (3) in Embodiment 1;

[0032] Figure 2 It is a schematic assembly diagram of the copper wire transition bushing (1), the thermocouple transition bushing (2), the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body in Embodiment 1;

[0033] Figure 3 It is a schematic assembly diagram of the filler metal, the copper wire transition bushing (1), the copper wire and the Y-TZP ceramic furnace body in Embodiment 1;

[0034] Figure 4 It is a schematic assembly diagram of the filler metal, the thermocouple transition bushing (2), the thermocouple and the Y-TZP ceramic furnace body in Embodiment 1;

[0035] Figure 5 It is a schematic assembly diagram of the filler metal, the gas pipe connection transition bushing (3), the gas pipe connection and the Y-TZP ceramic furnace body in Embodiment 1;

[0036] Figure 6 It is a diagram of the appearance and interface microstructure of the brazed joint between the Y-TZP ceramic furnace body and the gas pipe connection transition bushing (3) in Embodiment 1; Detailed Embodiments

[0037] The technical solution of the present invention is not limited to the following specific embodiments listed, and also includes any reasonable combination between the specific embodiments.

[0038] Specific Embodiment 1: The alloy transition bushing for brazing the socket structure between the Y-TZP ceramic furnace body and the metal component includes a copper wire transition bushing (1), a thermocouple transition bushing (2), and a gas pipe connection transition bushing (3); the copper wire transition bushing (1) consists of a copper wire sleeve (11) and a copper wire transition bushing flange (12), and the copper wire transition bushing flange (12) is arranged at one end of the copper wire sleeve (11); the thermocouple transition bushing (2) consists of a thermocouple sleeve (21) and a thermocouple transition bushing flange (22), and the thermocouple transition bushing flange (22) is arranged at one end of the thermocouple sleeve (21); the gas pipe connection transition bushing (3) is composed of a gas pipe connection sleeve (31) and a gas pipe connection transition bushing flange (32), and the gas pipe connection transition bushing flange (32) is arranged in the middle of the outer surface of the gas pipe connection sleeve (31).

[0039] This embodiment has the following beneficial effects:

[0040] 1. In this embodiment, the copper wire transition bushing (1), the thermocouple transition bushing (2), and the gas pipe connection transition bushing (3) are used for brazing transition between the metal component and the Y-TZP ceramic furnace body. The transition bushing can effectively relieve the residual stress between the Y-TZP ceramic furnace body of the induction heating furnace and the copper wire, the thermocouple, and the main gas pipe. And after the weld seam is tested under mechanical environment (conditions are 18g acceleration test, 12g sinusoidal vibration test, 15.5g random vibration test, and 1800g shock test) and temperature environment (-195°C to 195°C thermal cycle test), it will not crack and fail, meeting the application requirements of aerospace. At the same time, by virtue of the easy machinability characteristics of Kovar alloy, this invention processes the Kovar alloy into a transition bushing structure for brazing the ceramic and metal socket structure. Utilizing the characteristics of moderate thermal expansion coefficient and difficult corrosion of Kovar alloy, the residual thermal stress caused by the difference in thermal expansion coefficients of the two base metals during the brazing process of the socket structure ceramic and metal is greatly relieved, and the corrosion phenomenon of the metal base material in the socket joint is inhibited, and the mechanical properties, sealing performance, and thermal shock resistance of the joint are all significantly improved.

[0041] 2. The material of the transition bushing adopted in this embodiment is 4J50 Kovar alloy, which reacts well with the AgCuTi brazing filler metal used for welding ceramics. Therefore, the shear strength of the brazed joint between the transition bushing and the Y-TZP ceramic is extremely high, and the joint strength of the flat joint plus socket joint reaches 80 MPa.

[0042] 3. The transition bushing adopted in this embodiment effectively avoids the corrosion effect of the AgCuTi brazing filler metal on the copper wire and protects the integrity of the shape and size of the oxygen-free copper wire.

[0043] 4. In this embodiment, the solder foil strip is pre-bent and formed and placed in the weld seam, which greatly promotes the flow and filling of the liquid active solder into the cermet weld seam during brazing, resulting in excellent airtightness of the induction heating furnace weld seam. The leakage rate of the induction heating furnace weld seam is <5×10 -13 Pa·m 3 / s. It avoids the situation that due to the too small diameters of the copper wire and the K-type thermocouple wire, the depth-to-diameter ratio of the corresponding welding holes on the ceramic furnace body is too large, and due to the difficult operation, the solder cannot be pre-placed, the solder cannot be completely filled, and the airtightness of the induction heating furnace is poor.

[0044] 5. In this embodiment, the transition bushing is provided with a positioning platform (flange) and is used in cooperation with the brazing fixture. During welding, the weld gap can be ensured to remain unchanged, which is beneficial to the smooth flow and filling of the solder and the dimensional accuracy of the induction heating furnace.

[0045] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that the materials of the copper wire transition bushing (1), the thermocouple transition bushing (2), and the gas pipe connection transition bushing (3) are 4J50 Kovar alloy.

[0046] Specific Embodiment 3: The method for brazing the Y-TZP ceramic furnace body and the metal component using the alloy transition bushing for the socket joint structure of the Y-TZP ceramic furnace body and the metal component is carried out according to the following steps:

[0047] Step 1: Use a vernier caliper and a plug gauge to measure that the fit gaps between the welding holes and the transition bushing, and between the transition bushing and the metal component meet the brazing requirements;

[0048] The welding holes are the copper wire welding holes, the thermocouple welding holes, and the gas pipe welding holes on the Y-TZP ceramic furnace body;

[0049] The metal components are copper wire and thermocouple;

[0050] The transition bushings are the copper wire transition bushing (1), the thermocouple transition bushing (2), and the gas pipe connection transition bushing (3);

[0051] Step 2: Cut the AgCuTi solder foil strip into a parallelogram and a circular ring;

[0052] Step 3: Grind the cut AgCuTi solder foil strip with 400# sandpaper to remove the dense oxide skin on its surface, and then wash and dry it;

[0053] Step 4: Wrap the cleaned parallelogram AgCuTi solder foil strip around the outer surface of the copper wire sleeve (11) of the copper wire transition bushing (1), the outer surface of the thermocouple sleeve (21) of the thermocouple transition bushing (2), and the outer surface of the gas pipe connection sleeve (31) of the gas pipe connection transition bushing (3).

[0054] Step 5: Place the copper wire transition bushing (1) wrapped with AgCuTi solder foil strip into the copper wire welding hole, and place an annular AgCuTi solder foil strip between the copper wire transition bushing flange (12) in the copper wire transition bushing (1) and the Y-TZP ceramic furnace body; place the thermocouple transition bushing (2) wrapped with AgCuTi solder foil strip into the thermocouple welding hole, and place an annular AgCuTi solder foil strip between the thermocouple transition bushing flange (22) in the thermocouple transition bushing (2) and the Y-TZP ceramic furnace body; place the gas pipe connection transition bushing (3) wrapped with AgCuTi solder foil strip into the gas pipe welding hole, and place an annular AgCuTi solder foil strip between the gas pipe connection transition bushing flange (32) in the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body.

[0055] Step 6: Clean and dry the copper wire welding hole on the Y-TZP ceramic furnace body, the thermocouple welding hole on the Y-TZP ceramic furnace body, the gas pipe welding hole on the Y-TZP ceramic furnace body, and the metal components.

[0056] Step 7: Apply AgCuTi solder paste between the circumferential surface of the copper wire transition bushing flange (12) in the copper wire transition bushing (1) and the Y-TZP ceramic furnace body, and apply AgCuTi solder paste to the gap between the lower end surface of the copper wire transition bushing flange (12) and the lower end surface of the copper wire welding hole;

[0057] Place the thermocouple into the thermocouple sleeve (21) of the thermocouple transition bushing (2), apply AgCuTi solder paste between the circumferential surface of the thermocouple and the upper surface of the thermocouple transition bushing flange (22), apply AgCuTi solder paste between the circumferential surface of the thermocouple transition bushing flange (22) and the Y-TZP ceramic furnace body, and apply AgCuTi solder paste to the inner wall of the thermocouple welding hole on the lower end surface of the thermocouple sleeve (21) and the Y-TZP ceramic furnace body;

[0058] Apply AgCuTi solder paste between the circumferential surface of the gas pipe connection transition bushing flange (32) in the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body, and apply AgCuTi solder paste to the gap between the lower end surface of the gas pipe connection sleeve (31) of the gas pipe connection transition bushing (3) and the lower end surface of the gas pipe welding hole.

[0059] Step 8: Fix the copper wire transition bushing (1), the thermocouple transition bushing (2) and the air guide pipe transition bushing (3) by using a fixture to complete the pre-welding assembly work;

[0060] Step 9: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing;

[0061] Step 10: Take out the Y-TZP ceramic furnace body, polish the inner hole of the copper wire sleeve (11) in the copper wire transition bushing (1) and the copper wire to be welded, brush them with acetone, and then dry them;

[0062] Step 11: placing the copper wire in the inner hole of the copper wire sleeve (11) in the copper wire transition bushing (1), and applying paste-like AgCuInSn solder between the upper end surface of the copper wire sleeve (11) in the copper wire transition bushing (1) and the circumferential surface of the copper wire;

[0063] Step 12: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing.

[0064] 1. This embodiment uses a copper wire transition bushing (1), a thermocouple transition bushing (2) and a gas pipe transition bushing (3) for brazing transition between metal components and a Y-TZP ceramic furnace body. The transition bushing can effectively relieve the residual stress between the Y-TZP ceramic furnace body of the induction heating furnace and the copper wire, the thermocouple and the gas pipe main pipe. Moreover, the weld will not crack and fail after being assessed in a mechanical environment (conditions are 18g acceleration test, 12g sinusoidal vibration test, 15.5g random vibration test and 1800g impact test) and a temperature environment (-195℃~195℃ thermal cycle test), meeting the application requirements of aerospace. At the same time, the present invention takes advantage of the easy machining performance of Kovar alloy, uses Kovar alloy to process into a transition bushing structure for brazing ceramic and metal socket structures, and utilizes the characteristics of Kovar alloy with moderate thermal expansion coefficient and difficulty in corrosion to greatly alleviate the post-weld residual thermal stress caused by the difference in thermal expansion coefficient of the parent materials on both sides during the brazing process of the socket structure ceramic and metal, and the corrosion phenomenon of the metal parent material in the socket joint is suppressed, and the mechanical properties, sealing properties and thermal shock resistance of the joint are significantly improved.

[0065] 2. The material of the transition bushing used in this embodiment is 4J50 Kovar alloy, which reacts well with the AgCuTi brazing material used for welding ceramics. Therefore, the shear strength of the brazed joint between the transition bushing and the Y-TZP ceramic is extremely high, and the strength of the butt joint and socket joint reaches 80MPa.

[0066] 3. The transition bushing used in this embodiment effectively avoids the corrosion of the AgCuTi solder on the copper wire and protects the shape and size of the oxygen-free copper wire.

[0067] 4. In this embodiment, the solder foil strip is pre-bent and formed and placed in the weld seam, which greatly promotes the flow and filling of the liquid active solder into the cermet weld seam during brazing, resulting in excellent airtightness of the induction heating furnace weld seam. The leakage rate of the induction heating furnace weld seam is <5×10 -13 Pa·m 3 / s. It avoids the situation that due to the too small diameters of the copper wire and the K-type thermocouple wire, the depth-to-diameter ratio of the corresponding welding holes on the ceramic furnace body is too large, and due to the difficult operation, the solder cannot be pre-placed, the solder cannot be completely filled, and the airtightness of the induction heating furnace is poor.

[0068] 5. In this embodiment, the transition bushing is provided with a positioning platform (flange) and is used in cooperation with the brazing fixture. During welding, the weld seam gap can be ensured to remain unchanged, which is beneficial to the smooth flow and filling of the solder and the dimensional accuracy of the induction heating furnace.

[0069] Specific Embodiment Four: The difference between this embodiment and Specific Embodiment Three is that: the mating clearance between the measured welding hole and the transition bushing in Step One meets 0.095 - 0.105 mm.

[0070] Specific Embodiment Five: The difference between this embodiment and Specific Embodiment Three is that: the mating clearance between the transition bushing and the metal component in Step One meets 0.03 - 0.07 mm.

[0071] Specific Embodiment Six: The difference between this embodiment and Specific Embodiment Three is that: the thermocouple in Step One is a K-type Ni-based alloy thermocouple.

[0072] Specific Embodiment Seven: The difference between this embodiment and Specific Embodiment Three is that: the cleaning and drying process in Step Three is: ultrasonic cleaning for 1 - 30 min, and then drying in an oven at 150°C.

[0073] Specific Embodiment Eight: The difference between this embodiment and Specific Embodiment Three is that: the cleaning and drying process in Step Six is: ultrasonic cleaning for 1 - 30 min, and then drying in an oven at 150°C.

[0074] Specific Embodiment Nine: The difference between this embodiment and Specific Embodiment Three is that: the brazing process in Step Nine is: after the vacuum degree in the vacuum furnace reaches 5×10 -3 Pa, heat it to 750°C at a rate of 10°C / min, then heat it to 900°C at a rate of 5°C / min and hold for 90 min, and then cool it to 300°C at a rate of 5°C / min, and then cool it to room temperature with the furnace.

[0075] Specific Embodiment Ten: The difference between this embodiment and Specific Embodiment Three is that: the brazing process in Step Twelve is: after the vacuum degree in the vacuum furnace reaches 5×10 -3After reaching 100 Pa, heat it to 550 °C at a rate of 10 °C / min, then heat it to 700 °C at a rate of 5 °C / min and hold for 30 min, then cool it to 300 °C at a rate of 5 °C / min, and then cool it in the furnace to room temperature to complete the brazing of the induction heating furnace.

[0076] Example 1:

[0077] The alloy transition bushing for brazing the socket structure of the Y-TZP ceramic furnace body and the metal component in this example is used for brazing the Y-TZP ceramic furnace body and the metal component according to the following steps:

[0078] Step 1: Use a vernier caliper and a plug gauge to measure that the clearance between the welding hole and the transition bushing and the clearance between the transition bushing and the metal component meet the brazing requirements;

[0079] The measured clearance between the welding hole and the transition bushing meets 0.095 - 0.105 mm;

[0080] The clearance between the transition bushing and the metal component meets 0.03 - 0.07 mm;

[0081] The welding holes are the copper wire welding hole, the thermocouple welding hole, and the gas pipe welding hole on the Y-TZP ceramic furnace body;

[0082] The metal components are copper wires and thermocouples; the thermocouple is a K-type Ni-based alloy thermocouple;

[0083] The transition bushings are the copper wire transition bushing (1), the thermocouple transition bushing (2), and the gas pipe connection transition bushing (3);

[0084] Step 2: Cut the Ag69.5Cu27Ti3.5 solder foil tape into parallelograms and circular rings;

[0085] Step 3: Grind the cut Ag69.5Cu27Ti3.5 solder foil tape with 400# sandpaper to remove the dense oxide skin on its surface, and then perform cleaning and drying;

[0086] The cleaning and drying process is: ultrasonic cleaning for 15 min, and then drying in an oven at 150 °C;

[0087] Step 4: Wrap the cleaned parallelogram Ag69.5Cu27Ti3.5 solder foil tape on the outer surface of the copper wire sleeve (11) of the copper wire transition bushing (1), the outer surface of the thermocouple sleeve (21) of the thermocouple transition bushing (2), and the outer surface of the gas pipe connection sleeve (31) of the gas pipe connection transition bushing (3);

[0088] Step Five: Place the copper wire transition bushing (1) wrapped with Ag69.5Cu27Ti3.5 solder foil tape into the copper wire welding hole, and place an annular Ag69.5Cu27Ti3.5 solder foil tape between the copper wire transition bushing flange (12) in the copper wire transition bushing (1) and the Y-TZP ceramic furnace body; place the thermocouple transition bushing (2) wrapped with Ag69.5Cu27Ti3.5 solder foil tape into the thermocouple welding hole, and place an annular Ag69.5Cu27Ti3.5 solder foil tape between the thermocouple transition bushing flange (22) in the thermocouple transition bushing (2) and the Y-TZP ceramic furnace body; place the gas pipe connection transition bushing (3) wrapped with Ag69.5Cu27Ti3.5 solder foil tape into the gas pipe welding hole, and place an annular Ag69.5Cu27Ti3.5 solder foil tape between the gas pipe connection transition bushing flange (32) in the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body;

[0089] Step Six: Clean and dry the copper wire welding hole on the Y-TZP ceramic furnace body, the thermocouple welding hole on the Y-TZP ceramic furnace body, the gas pipe welding hole on the Y-TZP ceramic furnace body and the metal components;

[0090] The cleaning and drying process is as follows: ultrasonic cleaning for 1 - 30 min, and then drying in an oven at 150 °C;

[0091] Step Seven: Apply Ag69.5Cu27Ti3.5 solder paste between the circumferential surface of the copper wire transition bushing flange (12) in the copper wire transition bushing (1) and the Y-TZP ceramic furnace body, and apply Ag69.5Cu27Ti3.5 solder paste to the gap between the lower end surface of the copper wire transition bushing flange (12) and the lower end surface of the copper wire welding hole;

[0092] Place the thermocouple into the thermocouple sleeve (21) of the thermocouple transition bushing (2), apply Ag69.5Cu27Ti3.5 solder paste between the circumferential surface of the thermocouple and the upper surface of the thermocouple transition bushing flange (22), apply Ag69.5Cu27Ti3.5 solder paste between the circumferential surface of the thermocouple transition bushing flange (22) and the Y-TZP ceramic furnace body, and apply Ag69.5Cu27Ti3.5 solder paste to the inner wall of the thermocouple welding hole on the lower end surface of the thermocouple sleeve (21) and the Y-TZP ceramic furnace body;

[0093] Apply Ag69.5Cu27Ti3.5 solder paste between the circumferential surface of the gas pipe connection transition bushing flange (32) of the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body, and apply Ag69.5Cu27Ti3.5 solder paste to the gap between the lower end surface of the gas pipe connection sleeve (31) of the gas pipe connection transition bushing (3) and the lower end surface of the gas pipe welding hole;

[0094] Step 8: Fix the copper wire transition bushing (1), the thermocouple transition bushing (2) and the air guide pipe transition bushing (3) by using a fixture to complete the pre-welding assembly work;

[0095] Step 9: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing;

[0096] The brazing process is as follows: wait until the vacuum degree in the vacuum furnace reaches 5×10 -3 After Pa, it was heated to 750°C at a rate of 10°C / min, then heated to 900°C at a rate of 5°C / min and kept at that temperature for 90min, then cooled to 300°C at a rate of 5°C / min, and then cooled to room temperature with the furnace;

[0097] Step 10: Take out the Y-TZP ceramic furnace body, polish the inner hole of the copper wire sleeve (11) in the copper wire transition bushing (1) and the copper wire to be welded, brush them with acetone, and then dry them;

[0098] Step 11: placing the copper wire in the inner hole of the copper wire sleeve (11) in the copper wire transition bushing (1), and applying paste-like AgCuInSn solder between the upper end surface of the copper wire sleeve (11) in the copper wire transition bushing (1) and the circumferential surface of the copper wire;

[0099] Step 12: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing;

[0100] The brazing process is as follows: wait until the vacuum degree in the vacuum furnace reaches 5×10 -3 Pa, heat to 550℃ at a rate of 10℃ / min, then heat to 700℃ at a rate of 5℃ / min and keep warm for 30min, then cool to 300℃ at a rate of 5℃ / min, and then cool to room temperature with the furnace to complete the brazing of the induction heating furnace.

[0101] The welding effect of the transition bushing and the Y-TZP ceramic furnace body obtained in this case is good, and the air tightness index (leakage rate) of the induction heating furnace weld after welding is less than 5×10 -13 Pa·m 3 / s, and after the induction heating furnace has undergone aerospace identification-level sinusoidal vibration, random vibration, and 1800g impact tests, the induction heating furnace weld air tightness index (leakage rate) is still less than 5×10 -13 Pa·m 3 / s, and then experienced 4 rounds of low-temperature storage at -195℃ for 12h, 4 rounds of high-temperature storage at 195℃ for 12h, and 25.5 rounds of thermal cycles at -85℃ to 195℃, the air tightness index (leakage rate) of the induction heating furnace weld was still less than 5×10 -13 Pa·m 3 / s. The core indicators of the induction heating furnace fully meet the requirements of aerospace use.

[0102] The appearance and interfacial microstructure of the welded joint between the gas pipe connection transition bushing obtained in this example and the Y-TZP ceramic furnace body are as Figure 6 shown. The brazing rate of the joint of the gas pipe connection transition bushing reaches 100%, and there are no welding defects at the joint interface. Moreover, due to the extremely small difference in thermal expansion coefficients between the bushing and the ceramic, the residual stress after welding is effectively relieved, the strength of the joint after welding reaches 80 MPa, and the joint strength reaches 70 MPa after 25.5 cycles of -85°C to 195°C thermal cycling.

Claims

1. A method for brazing a Y-TZP ceramic furnace body and a metal component using an alloy transition bushing for the socket joint structure of the Y-TZP ceramic furnace body and the metal component, characterized in that: The method is carried out according to the following steps: Step 1: Use a vernier caliper and a plug gauge to measure the fit clearance between the welding hole and the transition bushing, and the fit clearance between the transition bushing and the metal component to meet the requirements of brazing; The welding holes are the copper wire welding holes on the Y-TZP ceramic furnace body, the thermocouple welding holes on the Y-TZP ceramic furnace body, and the gas pipe welding holes on the Y-TZP ceramic furnace body; The metal components are copper wires and thermocouples; The transition bushings are the copper wire transition bushing (1), the thermocouple transition bushing (2), and the gas pipe connection transition bushing (3); Step 2: Cut the AgCuTi filler metal foil into parallelograms and circular rings; Step 3: Grind the cut AgCuTi filler metal foil with 400# sandpaper to remove the dense oxide skin on its surface, and then clean and dry it; Step 4: Wrap the cleaned parallelogram AgCuTi filler metal foil around the outer surface of the copper wire sleeve (11) of the copper wire transition bushing (1), the outer surface of the thermocouple sleeve (21) of the thermocouple transition bushing (2), and the outer surface of the gas pipe connection sleeve (31) of the gas pipe connection transition bushing (3); Step 5: Place the copper wire transition bushing (1) wrapped with AgCuTi filler metal foil into the copper wire welding hole, and place a circular AgCuTi filler metal foil between the copper wire transition bushing flange (12) in the copper wire transition bushing (1) and the Y-TZP ceramic furnace body; Place the thermocouple transition bushing (2) wrapped with AgCuTi filler metal foil into the thermocouple welding hole, and place a circular AgCuTi filler metal foil between the thermocouple transition bushing flange (22) in the thermocouple transition bushing (2) and the Y-TZP ceramic furnace body; Place the gas pipe connection transition bushing (3) wrapped with AgCuTi filler metal foil into the gas pipe welding hole, and place a circular AgCuTi filler metal foil between the gas pipe connection transition bushing flange (32) in the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body; Step 6: Clean and dry the copper wire welding hole on the Y-TZP ceramic furnace body, the thermocouple welding hole on the Y-TZP ceramic furnace body, the gas pipe welding hole on the Y-TZP ceramic furnace body, and the metal components; Step 7: Apply AgCuTi solder paste between the circumferential surface of the copper wire transition bushing flange (12) in the copper wire transition bushing (1) and the Y-TZP ceramic furnace body, and apply AgCuTi solder paste to the gap between the lower end surface of the copper wire transition bushing flange (12) and the lower end surface of the copper wire welding hole; Place the thermocouple in the thermocouple sleeve (21) of the thermocouple transition bushing (2), apply AgCuTi solder paste between the circumferential surface of the thermocouple and the upper surface of the thermocouple transition bushing flange (22), apply AgCuTi solder paste between the circumferential surface of the thermocouple transition bushing flange (22) and the Y-TZP ceramic furnace body, and apply AgCuTi solder paste to the inner wall of the thermocouple welding hole on the lower end surface of the thermocouple sleeve (21) and the Y-TZP ceramic furnace body; Apply AgCuTi solder paste on the circumferential surface between the flange (32) of the gas pipe connection transition bushing (3) and the Y-TZP ceramic furnace body, and also apply AgCuTi solder paste on the gap between the lower end surface of the gas pipe connection sleeve (31) of the gas pipe connection transition bushing (3) and the lower end surface of the gas pipe welding hole; Step Eight: Fix the copper wire transition bushing (1), the thermocouple transition bushing (2) and the gas pipe connection transition bushing (3) with a tooling fixture to complete the pre-welding assembly work; Step Nine: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing; Step Ten: Take out the Y-TZP ceramic furnace body, grind the inner hole of the copper wire sleeve (11) in the copper wire transition bushing (1) and the copper wire to be welded, brush it with acetone, and then dry it; Step Eleven: Place the copper wire in the inner hole of the copper wire sleeve (11) in the copper wire transition bushing (1), and apply paste-like AgCuInSn filler metal between the upper end surface of the copper wire sleeve (11) in the copper wire transition bushing (1) and the circumferential surface of the copper wire; Step Twelve: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing; The alloy transition bushing for brazing the socket joint structure between the Y-TZP ceramic furnace body and the metal component includes a copper wire transition bushing (1), a thermocouple transition bushing (2) and a gas pipe connection transition bushing (3); the copper wire transition bushing (1) consists of a copper wire sleeve (11) and a copper wire transition bushing flange (12), and the copper wire transition bushing flange (12) is arranged at one end of the copper wire sleeve (11); the thermocouple transition bushing (2) consists of a thermocouple sleeve (21) and a thermocouple transition bushing flange (22), and the thermocouple transition bushing flange (22) is arranged at one end of the thermocouple sleeve (21); the gas pipe connection transition bushing (3) is composed of a gas pipe connection sleeve (31) and a gas pipe connection transition bushing flange (32), and the gas pipe connection transition bushing flange (32) is arranged in the middle of the outer surface of the gas pipe connection sleeve (31); the materials of the copper wire transition bushing (1), the thermocouple transition bushing (2) and the gas pipe connection transition bushing (3) are 4J50 kovar alloy.

2. The method for brazing a Y-TZP ceramic furnace body and a metal component by using an alloy transition bushing for brazing the socket structure of the Y-TZP ceramic furnace body and the metal component according to claim 1, characterized in that: The fit clearance between the welding hole and the transition bushing in Step One meets 0.095 - 0.105 mm.

3. The method for brazing a Y-TZP ceramic furnace body and a metal component using an alloy transition bushing for the socket joint structure of the Y-TZP ceramic furnace body and the metal component according to claim 1, characterized in that: The fit clearance between the transition bushing and the metal component in Step One meets 0.03 - 0.07 mm.

4. The method for brazing a Y-TZP ceramic furnace body and a metal component with an alloy transition bushing using the socket structure of the Y-TZP ceramic furnace body and the metal component according to claim 1, characterized in that: The thermocouple in Step One is a K-type Ni-based alloy thermocouple.

5. The method for brazing a Y-TZP ceramic furnace body and a metal component by using an alloy transition bushing for the socket joint structure of the Y-TZP ceramic furnace body and the metal component according to claim 1, characterized in that: The cleaning and drying process in Step Three is: ultrasonic cleaning for 1 - 30 min, and then drying in an oven at 150 °C.

6. The method for brazing a Y-TZP ceramic furnace body and a metal component by using an alloy transition bushing for the socket joint structure of the Y-TZP ceramic furnace body and the metal component according to claim 1, characterized in that: The cleaning and drying process in Step Six is: ultrasonic cleaning for 1 - 30 min, and then drying in an oven at 150 °C.

7. The method for brazing a Y-TZP ceramic furnace body and a metal component by using an alloy transition bushing for the socket joint structure of the Y-TZP ceramic furnace body and the metal component according to claim 1, characterized in that: The brazing process described in Step Nine is as follows: After the vacuum degree in the vacuum furnace reaches 5×10 -3 Pa, heat it to 750°C at a rate of 10°C / min, then heat it to 900°C at a rate of 5°C / min and hold for 90 min, then cool it to 300°C at a rate of 5°C / min, and then cool it to room temperature with the furnace.

8. The method for brazing a Y-TZP ceramic furnace body and a metal component using an alloy transition bushing for the socket joint structure of the Y-TZP ceramic furnace body and the metal component according to claim 1, characterized in that: The brazing process described in Step Twelve is as follows: After the vacuum degree in the vacuum furnace reaches 5×10 -3 Pa, it is heated to 550°C at a rate of 10°C / min, then heated to 700°C at a rate of 5°C / min and held for 30 min, then cooled to 300°C at a rate of 5°C / min, and then cooled to room temperature in the furnace to complete the brazing of the induction heating furnace.

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