Alloy transition lining for brazing of sleeving structure of Y-TZP ceramic furnace body and metal component and brazing method

Abstract

The invention discloses an alloy transition lining for brazing of a Y-TZP ceramic furnace body and metal component sleeving structure and a brazing method, and relates to an alloy transition lining for brazing and application. The problems that large residual stress exists when an existing Y-TZP ceramic furnace body is directly brazed with a copper wire, a K-type thermocouple wire and a 316L gas guide pipe main pipe, and a connector obtained through brazing is low in mechanical property, sealing property and thermal shock resistance are solved. The copper wire transition lining, the thermocouple transition lining and the gas guide pipe connecting pipe transition lining are used for brazing transition between the metal component and the Y-TZP ceramic furnace body, and the transition linings can effectively relieve residual stress between the Y-TZP ceramic furnace body of the induction heating furnace and a copper wire, a thermocouple and a gas guide pipe main pipe; the corrosion phenomenon of the metal base material in the sleeve joint is inhibited, and the mechanical property, the sealing property and the thermal shock resistance of the joint are obviously improved.

Description

Technical Field

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

[0002] Induction heating furnaces have been used in the aerospace field. For example, the volatile preparation unit of the volatile measurement instrument of the aerospace lunar soil volatile measurement instrument uses an induction heating furnace, which is used to measure the volatiles and isotope content in the lunar soil. It plays an important role in heating the lunar soil and preparing volatiles.

[0003] The functional part of the aerospace induction heating furnace is composed 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, the airtightness of the connection between the Y-TZP ceramic furnace body and other metal components must be ensured. Taking into account the differences in the weldability of ceramics and metals, as well as the temperature adaptability, technical requirements and special service conditions of aerospace products, the connection process between the Y-TZP ceramic furnace body and other metal components is mainly brazing, and AgCuTi active brazing filler metal is generally selected.

[0004] However, the physical and chemical properties of Y-TZP ceramics are quite different from those of metallic copper and nickel-based alloys, especially the linear expansion coefficient. The AgCuTi solder seriously dissolves the copper wire, which is very easy to be melted. In addition, direct welding of the Y-TZP ceramic furnace body with copper wire, K-type thermocouple wire and 316L air duct main pipe will produce large residual stress, resulting in reduced mechanical properties, sealing properties and thermal shock resistance of the joint. Summary of the invention

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

[0006] The alloy transition bushing for brazing the Y-TZP ceramic furnace body and metal component sleeve joint structure of the present invention comprises a copper wire transition bushing (1), a thermocouple transition bushing (2) and an air duct pipe transition bushing (3); the copper wire transition bushing (1) comprises 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) comprises 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 pipe transition bushing (3) comprises an air duct pipe connecting sleeve (31) and an air duct pipe transition bushing flange (32), and the air duct pipe transition bushing flange (32) is arranged at the middle of the outer surface of the air duct pipe connecting sleeve (21);

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

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

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

[0010] The metal components are copper wire and thermocouple;

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

[0012] Step 2: Cut the AgCuTi solder foil into parallelograms and rings;

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

[0014] Step 4: Wrapping the cleaned parallelogram-shaped AgCuTi solder foil strip on the outer surface of the copper wire sleeve (11) of the copper wire transition sleeve (1), the outer surface of the thermocouple sleeve (21) of the thermocouple transition sleeve (2), and the outer surface of the air pipe connecting sleeve (31) of the air pipe transition sleeve (3);

[0015] Step 5: placing a copper wire transition bushing (1) coated with AgCuTi solder foil in a copper wire welding hole, and placing a ring-shaped AgCuTi solder foil between the copper wire transition bushing flange (12) and the Y-TZP ceramic furnace body in the copper wire transition bushing (1); placing a thermocouple transition bushing (2) coated with AgCuTi solder foil in a thermocouple welding hole, and placing a ring-shaped AgCuTi solder foil between the thermocouple transition bushing flange (22) and the Y-TZP ceramic furnace body in the thermocouple transition bushing (2); placing an air duct connection pipe transition bushing (3) coated with AgCuTi solder foil in an air duct welding hole, and placing a ring-shaped AgCuTi solder foil between the air duct connection pipe transition bushing flange (32) and the Y-TZP ceramic furnace body in the air duct connection pipe transition bushing (3);

[0016] Step 6: Clean and dry the copper wire welding holes on the Y-TZP ceramic furnace body, the thermocouple welding holes on the Y-TZP ceramic furnace body, the air guide pipe welding holes on the Y-TZP ceramic furnace body and the metal components;

[0017] 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 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] Placing a thermocouple in a thermocouple sleeve (21) of a thermocouple transition sleeve (2), coating AgCuTi solder paste between the circumferential surface of the thermocouple and the upper surface of the thermocouple transition sleeve flange (22), coating AgCuTi solder paste between the circumferential surface of the thermocouple transition sleeve flange (22) and the Y-TZP ceramic furnace body, and coating AgCuTi solder paste on the lower end surface of the thermocouple sleeve (21) and the inner wall of the electric couple welding hole of the Y-TZP ceramic furnace body;

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

[0020] 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;

[0021] Step 9: Place the Y-TZP ceramic furnace body in a 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. This avoids the problem that the depth-to-diameter ratio of the corresponding welding holes on the ceramic furnace body is too large due to the small diameter of the copper wire and K-type thermocouple wire, the solder cannot be placed in advance due to difficult operation, the solder cannot be fully filled, and the induction heating furnace has poor air tightness.

[0030] 5. The transition bushing of the present invention is provided with a positioning platform (flange), which is used in conjunction with a brazing fixture to ensure that the weld gap remains unchanged during welding, which is beneficial to the smooth flow and filling of the brazing material and the dimensional accuracy of the induction heating furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of a copper wire transition bushing (1), a thermocouple transition bushing (2) and an air guide pipe transition bushing (3) in Example 1;

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

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

[0034] Figure 4 This is a schematic diagram of the assembly of the brazing material, the thermocouple transition bushing (2), the thermocouple and the Y-TZP ceramic furnace body of Example 1;

[0035] Figure 5 This is a schematic diagram of the assembly of the brazing material, the transition bushing (3) of the air duct pipe, the air duct pipe and the Y-TZP ceramic furnace body of Example 1;

[0036] Figure 6 This is the appearance and interface organization diagram of the brazed joint between the Y-TZP ceramic furnace body and the transition bushing (3) of the air guide pipe in Example 1; DETAILED DESCRIPTION

[0037] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any reasonable combination of the specific implementation modes.

[0038] Specific implementation method one: In this implementation method, the alloy transition bushing for brazing the Y-TZP ceramic furnace body and the metal component sleeve structure includes a copper wire transition bushing (1), a thermocouple transition bushing (2) and an air duct transition bushing (3); the copper wire transition bushing (1) is composed 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) is composed 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 transition bushing (3) is composed of an air duct connecting sleeve (31) and an air duct transition bushing flange (32), and the air duct transition bushing flange (32) is arranged in the middle of the outer surface of the air duct connecting sleeve (21).

[0039] This implementation has the following beneficial effects:

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 4. In this embodiment, the brazing material foil is pre-bent and formed into a shape and placed in the weld, which greatly promotes the flow and filling of the liquid active brazing material into the metal ceramic weld during brazing, making the induction heating furnace weld airtight and the induction heating furnace weld leakage rate <5×10 -13 Pa·m 3 / s. This avoids the problem that the depth-to-diameter ratio of the corresponding welding holes on the ceramic furnace body is too large due to the small diameter of the copper wire and K-type thermocouple wire, the solder cannot be placed in advance due to difficult operation, the solder cannot be fully filled, and the induction heating furnace has poor air tightness.

[0044] 5. In this embodiment, the transition bushing has a positioning platform (flange) and is used in conjunction with a brazing fixture to ensure that the weld gap remains unchanged during welding, which is beneficial to the smooth flow and filling of the brazing material and the dimensional accuracy of the induction heating furnace.

[0045] Specific implementation method 2: The difference between this implementation method and specific implementation method 1 is that the material of the copper wire transition bushing (1), the thermocouple transition bushing (2) and the air duct transition bushing (3) is 4J50 Kovar alloy.

[0046] Specific implementation method three: In this implementation method, the method of brazing the Y-TZP ceramic furnace body and the metal component using the alloy transition bushing for brazing 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 the clearance between the welding hole and the transition bushing, and the clearance between the transition bushing and the metal component to meet the brazing requirements;

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

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

[0050] The transition bushings are copper wire transition bushings (1), thermocouple transition bushings (2) and air pipe transition bushings (3);

[0051] Step 2: Cut the AgCuTi solder foil into parallelograms and rings;

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

[0053] Step 4: Wrapping the cleaned parallelogram-shaped AgCuTi solder foil strip on the outer surface of the copper wire sleeve (11) of the copper wire transition sleeve (1), the outer surface of the thermocouple sleeve (21) of the thermocouple transition sleeve (2), and the outer surface of the air pipe connecting sleeve (31) of the air pipe transition sleeve (3);

[0054] Step 5: placing a copper wire transition bushing (1) coated with AgCuTi solder foil in a copper wire welding hole, and placing a ring-shaped AgCuTi solder foil between the copper wire transition bushing flange (12) and the Y-TZP ceramic furnace body in the copper wire transition bushing (1); placing a thermocouple transition bushing (2) coated with AgCuTi solder foil in a thermocouple welding hole, and placing a ring-shaped AgCuTi solder foil between the thermocouple transition bushing flange (22) and the Y-TZP ceramic furnace body in the thermocouple transition bushing (2); placing an air duct connection pipe transition bushing (3) coated with AgCuTi solder foil in an air duct welding hole, and placing a ring-shaped AgCuTi solder foil between the air duct connection pipe transition bushing flange (32) and the Y-TZP ceramic furnace body in the air duct connection pipe transition bushing (3);

[0055] Step 6: Clean and dry the copper wire welding holes on the Y-TZP ceramic furnace body, the thermocouple welding holes on the Y-TZP ceramic furnace body, the air guide pipe welding holes 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 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;

[0057] Placing a thermocouple in a thermocouple sleeve (21) of a thermocouple transition sleeve (2), coating AgCuTi solder paste between the circumferential surface of the thermocouple and the upper surface of the thermocouple transition sleeve flange (22), coating AgCuTi solder paste between the circumferential surface of the thermocouple transition sleeve flange (22) and the Y-TZP ceramic furnace body, and coating AgCuTi solder paste on the lower end surface of the thermocouple sleeve (21) and the inner wall of the electric couple welding hole of the Y-TZP ceramic furnace body;

[0058] AgCuTi solder paste is applied between the circumferential surface of the gas pipe connecting sleeve flange (32) of the gas pipe connecting sleeve (3) and the Y-TZP ceramic furnace body, and AgCuTi solder paste is applied on the gap between the lower end surface of the gas pipe connecting sleeve (31) of the gas pipe connecting sleeve (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 brazing material foil is pre-bent and formed into a shape and placed in the weld, which greatly promotes the flow and filling of the liquid active brazing material into the metal ceramic weld during brazing, making the induction heating furnace weld airtight and the induction heating furnace weld leakage rate <5×10 -13 Pa·m 3 / s. This avoids the problem that the depth-to-diameter ratio of the corresponding welding holes on the ceramic furnace body is too large due to the small diameter of the copper wire and K-type thermocouple wire, the solder cannot be placed in advance due to difficult operation, the solder cannot be fully filled, and the induction heating furnace has poor air tightness.

[0068] 5. In this embodiment, the transition bushing has a positioning platform (flange) and is used in conjunction with a brazing fixture to ensure that the weld gap remains unchanged during welding, which is beneficial to the smooth flow and filling of the brazing material and the dimensional accuracy of the induction heating furnace.

[0069] Specific implementation method four: The difference between this implementation method and specific implementation method three is that: in step one, the matching clearance between the measured welding hole and the transition bushing meets the requirement of 0.095 to 0.105 mm.

[0070] Specific implementation method five: The difference between this implementation method and specific implementation method three is that: the matching clearance between the transition bushing and the metal component in step one meets the requirement of 0.03 to 0.07 mm.

[0071] Specific implementation method six: This implementation method is different from specific implementation method three in that: the thermocouple described in step one is a K-type Ni-based alloy thermocouple.

[0072] Specific implementation method 7: The difference between this implementation method and specific implementation method 3 is that the cleaning and drying process in step 3 is: ultrasonic cleaning for 1-30 minutes, and then drying in an oven at 150°C.

[0073] Specific implementation eight: This implementation differs from specific implementation three in that: the cleaning and drying process described in step six is: ultrasonic cleaning for 1-30 minutes, and then drying in an oven at 150°C.

[0074] Specific embodiment 9: This embodiment is different from the specific embodiment 3 in that: the brazing process described in step 9 is: 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 this temperature for 90 min, then cooled to 300°C at a rate of 5°C / min, and then cooled to room temperature with the furnace.

[0075] Specific embodiment 10: This embodiment is different from the specific embodiment 3 in that: the brazing process described in step 12 is: wait until the vacuum degree in the vacuum furnace is 5×10 -3Pa, 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.

[0076] Embodiment 1:

[0077] The method for brazing a Y-TZP ceramic furnace body and a metal component with an alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component in this embodiment is carried out according to the following steps:

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

[0079] The matching clearance between the measuring welding hole and the transition bushing meets the requirement of 0.095-0.105 mm;

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

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

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

[0083] The transition bushings are copper wire transition bushings (1), thermocouple transition bushings (2) and air pipe transition bushings (3);

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

[0085] Step 3: Grind the cut Ag69.5Cu27Ti3.5 solder foil with 400# sandpaper to remove the dense oxide scale on its surface, and then clean and dry it;

[0086] The cleaning and drying process is as follows: ultrasonic cleaning for 15 minutes, followed by drying in an oven at 150°C;

[0087] Step 4: Wrapping the cleaned parallelogram-shaped Ag69.5Cu27Ti3.5 solder foil strip on the outer surface of the copper wire sleeve (11) of the copper wire transition sleeve (1), the outer surface of the thermocouple sleeve (21) of the thermocouple transition sleeve (2), and the outer surface of the air pipe connecting sleeve (31) of the air pipe transition sleeve (3);

[0088] Step 5: Place the copper wire transition bushing (1) coated with Ag69.5Cu27Ti3.5 solder foil in the copper wire welding hole, and place a circular Ag69.5Cu27Ti3.5 solder foil between the copper wire transition bushing flange (12) and the Y-TZP ceramic furnace body in the copper wire transition bushing (1); place the thermocouple transition bushing (2) coated with Ag69.5Cu27Ti3.5 solder foil in the thermocouple welding hole, and place the thermocouple transition bushing (2) in the thermocouple transition bushing (2). A ring-shaped Ag69.5Cu27Ti3.5 solder foil is placed between a thermocouple transition bushing flange (22) and a Y-TZP ceramic furnace body; an air duct pipe transition bushing (3) coated with the Ag69.5Cu27Ti3.5 solder foil is placed in an air duct welding hole, and a ring-shaped Ag69.5Cu27Ti3.5 solder foil is placed between an air duct pipe transition bushing flange (32) and the Y-TZP ceramic furnace body in the air duct pipe transition bushing (3);

[0089] Step 6: Clean and dry the copper wire welding holes on the Y-TZP ceramic furnace body, the thermocouple welding holes on the Y-TZP ceramic furnace body, the air guide pipe welding holes on the Y-TZP ceramic furnace body and the metal components;

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

[0091] Step 7: 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 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;

[0092] Placing a thermocouple in a thermocouple sleeve (21) of a thermocouple transition sleeve (2), coating Ag69.5Cu27Ti3.5 solder paste between the circumferential surface of the thermocouple and the upper surface of the thermocouple transition sleeve flange (22), coating Ag69.5Cu27Ti3.5 solder paste between the circumferential surface of the thermocouple transition sleeve flange (22) and the Y-TZP ceramic furnace body, and coating Ag69.5Cu27Ti3.5 solder paste on the lower end surface of the thermocouple sleeve (21) and the inner wall of the electric couple welding hole of the Y-TZP ceramic furnace body;

[0093] Ag69.5Cu27Ti3.5 solder paste is applied between the circumferential surface of the gas pipe transition bushing flange (32) of the gas pipe transition bushing (3) and the Y-TZP ceramic furnace body, and Ag69.5Cu27Ti3.5 solder paste is applied on the gap between the lower end surface of the gas pipe connecting sleeve (31) of the gas pipe 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 this 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 is 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 interface structure of the welded joint between the transition bushing of the air guide pipe and the Y-TZP ceramic furnace body obtained in this example are as follows Figure 6 As shown. The brazing rate of the transition bushing of the air duct is 100%, and there is no welding defect at the joint interface. And because the difference in thermal expansion coefficient between the bushing and the ceramic is very small, the residual stress after welding is effectively relieved, and the joint strength after welding reaches 80MPa. After 25.5 rounds of -85℃~195℃ thermal cycles, the joint strength reaches 70MPa.

Claims

1. An alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component sleeve structure, characterized in that: The alloy transition bushing for brazing the Y-TZP ceramic furnace body and the metal component sleeve structure comprises a copper wire transition bushing (1), a thermocouple transition bushing (2) and an air duct pipe transition bushing (3); the copper wire transition bushing (1) comprises 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) comprises 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 pipe transition bushing (3) comprises an air duct pipe connecting sleeve (31) and an air duct pipe transition bushing flange (32), and the air duct pipe transition bushing flange (32) is arranged at the middle of the outer surface of the air duct pipe connecting sleeve (21).

2. The alloy transition bushing for brazing the Y-TZP ceramic furnace body and metal component sleeve structure according to claim 1 is characterized in that: The copper wire transition bushing (1), the thermocouple transition bushing (2) and the air guide pipe transition bushing (3) are made of 4J50 Kovar alloy.

3. A method for brazing a Y-TZP ceramic furnace body and a metal component using the alloy transition bushing for brazing the Y-TZP ceramic furnace body and metal component sleeve structure as claimed in claim 1, characterized in that: The method proceeds as follows: Step 1: Use a vernier caliper and a plug gauge to measure the clearance between the welding hole and the transition bushing, and the clearance between the transition bushing and the metal component to meet the brazing requirements; The welding holes are copper wire welding holes on the Y-TZP ceramic furnace body, thermocouple welding holes on the Y-TZP ceramic furnace body, and air guide pipe welding holes on the Y-TZP ceramic furnace body; The metal components are copper wire and thermocouple; The transition bushings are copper wire transition bushings (1), thermocouple transition bushings (2) and air pipe transition bushings (3); Step 2: Cut the AgCuTi solder foil into parallelograms and rings; Step 3: Grind the cut AgCuTi solder foil with 400# sandpaper to remove the dense oxide scale on its surface, and then clean and dry it; Step 4: Wrapping the cleaned parallelogram-shaped AgCuTi solder foil strip on the outer surface of the copper wire sleeve (11) of the copper wire transition sleeve (1), the outer surface of the thermocouple sleeve (21) of the thermocouple transition sleeve (2), and the outer surface of the air duct pipe connecting sleeve (31) of the air duct pipe transition sleeve (3); Step 5: placing a copper wire transition bushing (1) coated with AgCuTi solder foil in a copper wire welding hole, and placing a ring-shaped AgCuTi solder foil between the copper wire transition bushing flange (12) and the Y-TZP ceramic furnace body in the copper wire transition bushing (1); placing a thermocouple transition bushing (2) coated with AgCuTi solder foil in a thermocouple welding hole, and placing a ring-shaped AgCuTi solder foil between the thermocouple transition bushing flange (22) and the Y-TZP ceramic furnace body in the thermocouple transition bushing (2); placing an air duct connection pipe transition bushing (3) coated with AgCuTi solder foil in an air duct welding hole, and placing a ring-shaped AgCuTi solder foil between the air duct connection pipe transition bushing flange (32) and the Y-TZP ceramic furnace body in the air duct connection pipe transition bushing (3); Step 6: Clean and dry the copper wire welding holes on the Y-TZP ceramic furnace body, the thermocouple welding holes on the Y-TZP ceramic furnace body, the air guide pipe welding holes 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 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; Placing a thermocouple in a thermocouple sleeve (21) of a thermocouple transition sleeve (2), coating AgCuTi solder paste between the circumferential surface of the thermocouple and the upper surface of the thermocouple transition sleeve flange (22), coating AgCuTi solder paste between the circumferential surface of the thermocouple transition sleeve flange (22) and the Y-TZP ceramic furnace body, and coating AgCuTi solder paste on the lower end surface of the thermocouple sleeve (21) and the inner wall of the electric couple welding hole of the Y-TZP ceramic furnace body; AgCuTi solder paste is applied between the circumferential surface of the gas pipe connecting sleeve flange (32) of the gas pipe connecting sleeve (3) and the Y-TZP ceramic furnace body, and AgCuTi solder paste is applied on the gap between the lower end surface of the gas pipe connecting sleeve (31) of the gas pipe connecting sleeve (3) and the lower end surface of the gas pipe welding hole; 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; Step 9: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing; 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; 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; Step 12: Place the Y-TZP ceramic furnace body in a vacuum furnace for brazing.

4. The method for brazing a Y-TZP ceramic furnace body and a metal component by using an alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component sleeve structure according to claim 3, characterized in that: In step 1, the fitting clearance between the welding hole and the transition bushing is measured to meet the requirement of 0.095 to 0.105 mm.

5. The method for brazing a Y-TZP ceramic furnace body and a metal component by using an alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component sleeve structure according to claim 3, characterized in that: In step 1, the matching clearance between the transition bushing and the metal component meets the requirement of 0.03-0.07 mm.

6. The method for brazing a Y-TZP ceramic furnace body and a metal component by using an alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component sleeve structure according to claim 3, characterized in that: The thermocouple in step 1 is a K-type Ni-based alloy thermocouple.

7. The method for brazing a Y-TZP ceramic furnace body and a metal component by using an alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component sleeve structure according to claim 3, characterized in that: The cleaning and drying process in step 3 is: ultrasonic cleaning for 1-30 minutes, and then drying in an oven at 150°C.

8. The method for brazing a Y-TZP ceramic furnace body and a metal component using an alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component sleeve structure according to claim 3, characterized in that: The cleaning and drying process in step six is: ultrasonic cleaning for 1-30 minutes, and then drying in an oven at 150°C.

9. The method for brazing a Y-TZP ceramic furnace body and a metal component using an alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component sleeve structure according to claim 3, characterized in that: Step 9: When 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 this temperature for 90 min, then cooled to 300°C at a rate of 5°C / min, and then cooled to room temperature with the furnace.

10. The method for brazing a Y-TZP ceramic furnace body and a metal component using an alloy transition bushing for brazing a Y-TZP ceramic furnace body and a metal component sleeve structure according to claim 3, characterized in that: Step 12: 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.

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