Protector heating wire welding method and welding equipment

Abstract

The present invention discloses a protector heating wire welding method and welding equipment, the welding method comprising: S1, pre-treating the brazing sides of several heating wires into a truncated cone shape, and dividing the brazing sides into a first welding surface and a second welding surface; S2, fixing the heating wire with a vertical clamp, placing a solder sheet on the first welding surface, activating an induction heating part after introducing an inert gas, and controlling the rotation of a single-sided vertical clamp to perform friction welding; S3, fixing the heating wire with a horizontal clamp, activating the induction heating part, introducing oxygen and controlling the rotation of the bidirectional horizontal clamp to form a thin oxide layer on the surface of the heating wire; S4, uniformly spraying a mixture of solder powder and flux onto the rotating heating wire, and feeding the heating wire layer by layer; S5, obtaining the heating welding wire after cooling; the welding equipment comprises an induction heating part, a working part and a feeding part arranged inside the equipment body; the present invention improves welding quality, strength and corrosion resistance, and also ensures the safety and stability of the welding part.

Description

Technical Field

[0001] The present invention relates to the field of welding technology, in particular to the field of brazing technology, and specifically to a protector heating wire welding method and welding equipment thereof. Background Art

[0002] A protector heating wire is a component used to heat the protector. It is usually made of conductive material and is connected to the corresponding circuit or device through welding to achieve the heating function. The purpose of welding is to ensure good contact and stable conduction between the protector heating wire and the circuit or device.

[0003] Induction brazing is currently the most common method for welding heating wires. It utilizes high-frequency, medium-frequency, or industrial-frequency induced current as a heat source. It is considered the cleanest and most environmentally friendly method of heating and welding. During induction brazing, the brazed portion of the part is placed in an alternating magnetic field. This portion of the base metal is heated by the resistive heat generated by the induced current within the field.

[0004] However, under the action of the alternating electromagnetic field, the current distribution inside the part is uneven, and the current is concentrated in a thin layer on the surface of the part. The closer to the surface of the part, the greater the current density, the higher the frequency, and the smaller the current penetration depth. Although the surface layer is heated rapidly, the heated thickness becomes thinner. The interior of the part can only be heated by heat conduction from the surface layer to the inside, resulting in the skin effect.

[0005] In addition, the solder usually has a certain thickness during induction welding. However, if the heating is insufficient, only the surface of the solder will melt, while the liquid solder will not be completely formed inside, resulting in uneven heating and pores inside the solder. These pores will affect the strength and sealing performance during brazing.

[0006] Therefore, it is necessary to provide a protector heating wire welding device and a welding method thereof that improve the skin effect and reduce the occurrence of pores, so as to improve the above-mentioned problems. Summary of the Invention

[0007] The present invention overcomes the deficiencies of the prior art and provides a protector heating wire welding method and welding equipment thereof.

[0008] To achieve the above object, the present invention adopts the following technical solution: a method for welding a protector heating wire, comprising the following steps:

[0009] S1. Pretreatment: Pretreatment of the soldering sides of the plurality of heating wires into a truncated cone shape, and dividing the soldering sides into a first soldering surface and a second soldering surface; mechanical treatment until the first soldering surface has a rough surface and the second soldering surface has a smooth surface;

[0010] S2. First welding: Fix several heating wires with vertical clamps, place a thin sheet of solder on the first welding surface, introduce inert gas and activate the induction heating part, and control the rotation of the single-side vertical clamp to perform friction welding, then stop heating;

[0011] S3, surface treatment: Fix the heating wire obtained after the first welding in S2 with a horizontal clamp, activate the induction heating part, introduce oxygen and control the rotation of the bidirectional horizontal clamp to form a thin oxide layer on the surface of the heating wire;

[0012] S4, secondary welding: Inert gas is introduced, and a mixture of solder powder and flux is evenly sprayed onto the rotating heating wire through the feeding part, and the heating wire is brazed layer by layer;

[0013] S5. Welding is completed: After stopping heating, the heated welding wire is obtained after cooling.

[0014] In a preferred embodiment of the present invention, in S2, the specific steps of activating the induction heating part after the inert gas is introduced are:

[0015] S21. After introducing inert gas into the equipment through the ventilation part by connecting an inert gas pump to the ventilation part for 7-8 seconds, the induction heating part is activated, and the induction heating current is set to 300-700A, the current frequency is set to 50-100Hz, and the duration of induction heating is set to 5-6 seconds;

[0016] S22. Keep the vertical clamp on one side stationary and control the vertical clamp on the other side to rotate for friction welding. The rotation speed is 600-1100 r / min, the friction pressure is 1.2-2.5 MPa, the friction time is 0.2-0.5 s, and the top forging pressure is 55-67 MPa.

[0017] In a preferred embodiment of the present invention, in S2, when a solder sheet is placed on the first welding surface, the thickness of the solder sheet is not greater than 1 mm; the solder sheet is a nickel-based alloy, including at least one of ENiCrMo-3, ERNiCrMo-11, ERCuNi, and ERNiCrMo-4.

[0018] In a preferred embodiment of the present invention, the inert gas is one or more of helium, neon, argon, krypton, xenon and radon.

[0019] In a preferred embodiment of the present invention, in S3, introducing oxygen and controlling the rotation of the bidirectional horizontal clamping member specifically includes the following steps:

[0020] S31, connect the oxygen pump to the ventilation part to introduce oxygen into the equipment, and the oxygen concentration introduced is 14-20ppm;

[0021] S32. Control the vertical clamps on both sides to drive the heating wire to rotate in the same direction at a speed of 65-130 r / min.

[0022] In a preferred embodiment of the present invention, in S3, the concentration of the oxygen introduced is 5.3% to 7.5%.

[0023] In a preferred embodiment of the present invention, in S4, the steps of preparing the mixture of solder powder and flux are specifically as follows:

[0024] S41. The solder used in the secondary soldering is a silver-copper alloy, which is at least one of Ag99.95, AgCu3, AgCu5, AgCu7.5, AgCu10, AgCu15, AgCu20, AgCu28, and AgCu50;

[0025] S42, selecting a flux to be used for secondary welding, which is one of NaF, NH4Cl and KF;

[0026] S43, adding solder powder to the flux, with the mass ratio of solder powder to flux being 45-55:15-25; and grinding the solder powder into a solder flux mixed powder with a particle size of 55-90 μm.

[0027] In a preferred embodiment of the present invention, in said S1, the material of the heating wire is one of FeCrAl alloy 1450 and NiCr alloy 1380; and the diameter of the heating wire is not less than 3 mm, and the thickness of the flat strip is not less than 2 mm.

[0028] In a preferred embodiment of the present invention, in S1, the minimum distance D between the induction heating parts is not less than the diameter of the heating wire.

[0029] The present invention also provides a protector heating wire welding device, comprising: a device body, and an induction heating part, a working part, and a feeding part arranged inside the device body;

[0030] The equipment body includes: a welding chamber, an operating door provided on the welding chamber, an observation window provided on the operating door, and a plurality of universal wheels provided on the bottom of the equipment body;

[0031] The induction heating part includes: a first conductive part and a second conductive part arranged opposite to each other, and a plurality of high-frequency devices electrically connected to the first conductive part and the second conductive part; the first conductive part and the second conductive part are both conductive loops;

[0032] The working part includes: a vertical clamping member and a horizontal clamping member arranged inside the main body of the device, a rotating member and a telescopic member arranged on the vertical clamping member and the horizontal clamping member, and a ventilation member arranged inside the main body of the device; the ventilation member is connected to an inert gas pump and an oxygen pump arranged outside;

[0033] The feeding part includes: a plurality of feeding pipes arranged on both sides of the vertical clamping piece, and a feeding spray hole arranged on one side of the feeding pipe.

[0034] In a preferred embodiment of the present invention, the vertical clamping member includes a first clamping member and a second clamping member respectively arranged on the top inner wall and the bottom inner wall of the equipment body; the horizontal clamping member includes a third clamping member and a fourth clamping member respectively arranged on both sides of the inner wall of the equipment body.

[0035] In a preferred embodiment of the present invention, the diameter of the feeding nozzle is 0.3-0.5 mm.

[0036] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0037] (1) The present invention provides a protector heating wire welding method and welding equipment thereof. The protector heating wire welding method is combined with the welding equipment to improve the welding quality, strength and corrosion resistance through the steps of pretreatment, friction welding, surface treatment, induction welding and layer-by-layer loading, while also ensuring the safety and stability of the welding part.

[0038] (2) The present invention pre-treats the welding side of the heating wire, including shape adjustment and surface treatment; by pre-treating the welding side into a truncated cone shape, the welding area can be increased and the welding strength can be improved; at the same time, by making the surface of the first welding surface rough, the contact area with the solder can be increased, thereby improving the brazing effect; by making the surface of the second welding surface smooth, the area of ​​the solder remaining on the second welding surface can be reduced, thereby avoiding affecting the secondary welding.

[0039] (3) The present invention places a solder sheet on the first welding surface during the first welding, and controls the thickness of the sheet to accurately ensure the amount of solder during the first welding. The induction heating part activates the heating wire for friction welding, combining multiple welding methods and only controlling the rotation of the one-way vertical clamp for friction welding. This vertical clamping and rotating friction welding method can achieve efficient and uniform welding, and improve welding speed and quality.

[0040] (4) The present invention introduces oxygen and performs induction heating before the second welding, and the oxygen reacts with the heating wire to form a thin oxide layer on the surface, thereby processing the second welding surface into a rough welding surface. The rough grooves on the surface of the heating wire play a special capillary role, which can improve the wetting and spreading of the solder on the heating wire; then, a mixture of solder powder and flux is sprayed on the second welding surface, which increases the contact area between the solder powder and flux and the second welding surface and prolongs the time that the solder powder and flux remain on the second welding surface.

[0041] (5) By spraying a mixture of solder powder and flux on the second welding surface during secondary welding, the generated oxide layer can be removed while increasing the retention area, thereby avoiding the adverse effects of the oxide layer on the welding strength; and by controlling the rotation speed, the heating wire is loaded layer by layer. This layer-by-layer loading method can ensure that the solder and flux are evenly covered on the surface of the heating wire, thereby preventing the problem of pores inside the solder due to the difficulty in fully melting the center in the existing technology, thereby improving the welding quality and strength.

[0042] (6) The present invention stops heating after the first weld, which can prevent the heating wire from overheating and reduce the occurrence of thermal stress and deformation. After the second weld, it is also necessary to wait for the weld to cool down, which can ensure that the temperature of the weld part is reduced to a safe range, further reducing the occurrence of thermal stress and deformation.

[0043] (7) The present invention is divided into primary welding and secondary welding. The primary welding fixes the solder sheet on the first welding surface by unidirectional friction welding, ensuring sufficient contact area between the solder and the heating wire, thereby improving the brazing effect. A solder with a lower melting point than the solder used in the primary welding is selected and made into powder for secondary welding, thereby increasing the contact area between the solder and the welding surface without affecting the primary welding joint, thereby further improving the brazing effect.

[0044] (8) The present invention can realize the process of loading materials layer by layer by simultaneously controlling the temperature and speed of induction brazing, gradually building up the welding stack, and ensuring that each layer has sufficient solder and flux; and can ensure that the solder and flux are evenly covered on the surface of the heating wire, which can improve the welding quality and strength and avoid the occurrence of local poor welding or weak areas; at the same time, the amount of solder and flux used can be more accurately controlled, saving material costs and improving welding efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts.

[0046] Figure 1 This is a flow chart of Example 1 of the heating wire welding method of the present invention;

[0047] Figure 2 This is an overall three-dimensional structural diagram of a fourth embodiment of a heating wire welding device according to the present invention;

[0048] Figure 3 1 is a schematic diagram of the overall cross-sectional structure of a fourth embodiment of a heating wire welding device according to the present invention;

[0049] Figure 4 This is a cross-sectional perspective structural diagram of the working portion of the fourth embodiment of the heating wire welding device of the present invention;

[0050] Figure 5 1 is a schematic cross-sectional view of the induction heating portion of the fourth embodiment of the heating wire welding device of the present invention;

[0051] Figure 6 This is a cross-sectional perspective structural diagram of the vertical clamping member and the horizontal clamping member in the fourth embodiment of the heating wire welding device of the present invention;

[0052] Figure 7 This is a cross-sectional perspective structural diagram of the feeding portion of the fourth embodiment of the heating wire welding device of the present invention;

[0053] In the figure: 1. Equipment body; 11. Welding chamber; 12. Operating door; 13. Observation window; 14. Universal wheel; 2. Induction heating part; 21. First conductive part; 22. Second conductive part; 23. Several high-frequency devices; 3. Working part; 31. Vertical clamping part; 311. First clamping part; 312. Second clamping part; 32. Horizontal clamping part; 321. Third clamping part; 322. Fourth clamping part; 33. Rotating part; 34. Telescopic part; 35. Ventilation part; 4. Feeding part; 41. Feeding pipe; 42. Feeding nozzle. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Example 1

[0055] This embodiment uses the present invention as Figure 1 The welding method shown is for welding a heating wire with a diameter of 3mm and a flat strip thickness of 2mm; the specific steps are as follows:

[0056] S1. Preprocessing:

[0057] (1) Select a heating wire made of nickel-chromium alloy with a diameter of 3 mm and a flat strip thickness of 2 mm;

[0058] (2) Grinding the surface of the heating wire using a grinding wheel, pre-processing the brazing side of several heating wires into a truncated cone shape, and dividing the brazing side into a first welding surface and a second welding surface;

[0059] (3) The surface of the first weld surface is rough. Use a polishing disc to polish the second weld surface until it is smooth.

[0060] The shape of the welding side of the heating wire is adjusted and the surface is treated. The welding side is pre-treated into a truncated cone shape, which increases the welding area and improves the welding strength. By making the surface of the first welding surface rough, the contact area with the solder can be increased, thereby improving the brazing effect. By making the surface of the second welding surface smooth, the area of ​​the solder remaining on the second welding surface can be reduced, thereby avoiding affecting the secondary welding. The heating wire is set to 3mm and the flat strip thickness is 2mm, which also ensures the service life of the heating wire.

[0061] S2. First welding:

[0062] (1) Fix the two heating wires with a vertical clamp, place a 0.5 mm thick solder sheet on the first welding surface of the heating wire supported by the second clamp, and the solder sheet is ENiCrMo-3. Adjust the minimum distance D between the induction heating parts to 3.5 mm;

[0063] (2) After nitrogen is introduced for 7 seconds, the induction heating unit is activated, the induction heating current is set to 450A, the current frequency is set to 65Hz, and the duration of induction heating is set to 6 seconds;

[0064] (3) Keep the vertical clamp on one side stationary and control the vertical clamp on the other side to rotate for friction welding. The rotation speed is 750r / min, the friction pressure is 2MPa, the friction time is 0.3s, and the forging pressure is 63MPa.

[0065] (4) After controlling the rotation of the single-sided vertical clamp for friction welding, stop heating.

[0066] By placing a brazing material sheet on the first welding surface during the first welding and controlling the thickness of the sheet to 0.5mm, the amount of brazing material during the first welding can be accurately guaranteed; the induction heating part can be activated after nitrogen is introduced for 7 seconds to protect the induction heating part;

[0067] The induction heating unit activates the heating wire for friction welding, combining multiple welding methods. It only controls the one-way rotation of the vertical clamp for friction welding. The rotation speed is controlled to 750r / min, the friction pressure during friction welding is 2MPa, the friction time is 0.3, and the forging pressure is 63MPa. The heating wire is quickly rubbed while being heated. This vertical clamping and rotating friction welding method can achieve efficient and uniform welding, improving welding speed and quality.

[0068] Stop heating after the first weld to prevent the heating wire from overheating and reduce thermal stress and deformation.

[0069] S3. Surface treatment:

[0070] (1) Fix the heating wire obtained after the first welding in S2 with a horizontal clamp, activate the induction heating part for 5 seconds, and connect the oxygen pump to the ventilation part to introduce oxygen into the equipment. The oxygen concentration is 14ppm.

[0071] (2) Control the vertical clamps on both sides to drive the heating wire to rotate in the same direction at a speed of 65 r / min;

[0072] (3) After the rotation of the bidirectional horizontal clamp stops, a thin oxide layer is formed on the surface of the heating wire.

[0073] Before the secondary welding, an oxygen concentration of 14ppm is introduced and induction heating is performed. The rotation speed is set to 65r / min, and the two-way rotation is performed. The oxygen reacts with the heating wire to form a thin oxide layer on the surface. By controlling the oxygen concentration to 14ppm, the oxygen introduced can be completely consumed after the oxide layer is formed, avoiding the impact of oxygen residue in the subsequent operation.

[0074] The formation of a thin oxide layer also roughens the second weld surface. The rough grooves on the heating wire surface act as a capillary force, enhancing the wetting and spreading of the solder on the heating wire. This provides a base for the subsequent spraying of the solder powder and flux mixture on the second weld surface, increasing the contact area between the solder powder and flux and the second weld surface, and extending the time the solder powder and flux remain on the second weld surface.

[0075] S4, secondary welding:

[0076] (1) The solder used in the secondary welding is a silver-copper alloy, which is a mixture of AgCu3 and AgCu5, where the doping concentration of AgCu5 is 2.8wt%;

[0077] (2) NaF is selected as the flux used for secondary welding;

[0078] (3) Add solder powder to the flux with a mass ratio of solder powder to flux being 45:15; grind the mixture into a solder-flux mixed powder with a particle size of 55 μm;

[0079] (4) After nitrogen is introduced for 7 seconds, the induction heating part is activated, and the induction heating current is set to 550A, the current frequency is set to 50Hz, and the duration of induction heating is set to 5s; a mixture of solder powder and flux is evenly sprayed onto the rotating heating wire through the feeding part, and the rotation speed is maintained at 65r / min to feed the heating wire layer by layer for brazing.

[0080] During secondary welding, a mixture of solder powders AgCu3 and AgCu5 and flux NaF is sprayed on the second welding surface and ground into a solder-flux mixed powder with a particle size of 55 μm, so that the powder can adhere to the oxide layer. This can increase the retention area of ​​the solder-flux mixed powder while removing the oxide layer generated in S3, thus preventing the oxide layer from adversely affecting the welding strength.

[0081] The heating wire is loaded layer by layer by controlling the rotation speed to 65 r / min to ensure the uniformity between layers during loading. This layer-by-layer loading method can ensure that the solder and flux are evenly covered on the surface of the heating wire, preventing the problem of pores inside the solder due to difficulty in fully melting the center in the existing technology, thereby improving the welding quality and strength.

[0082] S5. Welding is completed: After stopping heating, the heated welding wire is obtained after cooling.

[0083] After the secondary welding, wait for it to cool down to ensure that the temperature of the welding part drops to a safe range, further reducing the occurrence of thermal stress and deformation. Example 2

[0084] This embodiment uses the present invention as Figure 1 The welding method shown is for welding a heating wire with a diameter of 4mm and a flat strip thickness of 3.2mm. The specific steps are as follows:

[0085] S1. Preprocessing:

[0086] (4) Select a heating wire made of nickel-chromium alloy with a diameter of 4 mm and a flat strip thickness of 3.2 mm;

[0087] (5) Grinding the surface of the heating wire using a grinding wheel, pre-processing the brazing side of several heating wires into a truncated cone shape, and dividing the brazing side into a first welding surface and a second welding surface;

[0088] (6) The surface of the first weld surface is rough. Use a polishing disc to polish the second weld surface until the surface is smooth.

[0089] S2. First welding:

[0090] (5) Fix the two heating wires with a vertical clamp, place a 0.8 mm thick solder sheet on the first welding surface of the heating wire supported by the second clamp, and the solder sheet is ERNiCrMo-11. Adjust the minimum distance D between the induction heating parts to 4.5 mm;

[0091] (6) After nitrogen was introduced for 8 seconds, the induction heating unit was activated, the induction heating current was set to 520 A, the current frequency was set to 72 Hz, and the duration of induction heating was set to 6 seconds;

[0092] (7) Keep the vertical clamp on one side stationary and control the vertical clamp on the other side to rotate for friction welding. The rotation speed is 810 r / min, the friction pressure is 2.3 MPa, the friction time is 0.4 s, and the forging pressure is 65 MPa.

[0093] (8) After controlling the rotation of the single-sided vertical clamp for friction welding, stop heating.

[0094] S3. Surface treatment:

[0095] (4) Fix the heating wire obtained after the first welding in S2 with a horizontal clamp, activate the induction heating part for 5 seconds, and connect the oxygen pump to the ventilation part to introduce oxygen into the equipment. The oxygen concentration introduced is 16 ppm;

[0096] (5) Control the vertical clamps on both sides to drive the heating wire to rotate in the same direction at a speed of 79 r / min;

[0097] (6) After the rotation of the bidirectional horizontal clamp stops, a thin oxide layer is formed on the surface of the heating wire.

[0098] S4, secondary welding:

[0099] (5) The solder used in the secondary welding is a silver-copper alloy, which is a mixture of AgCu10 and AgCu15, where the doping concentration of AgCu15 is 2.5wt%;

[0100] (6) NaF is selected as the flux used for secondary welding;

[0101] (7) Add solder powder to the flux, with the mass ratio of solder powder to flux being 49:17; grind the mixture into a solder-flux mixed powder with a particle size of 60 μm;

[0102] (8) After nitrogen is introduced for 7 seconds, the induction heating part is activated, and the induction heating current is set to 600A, the current frequency is set to 55Hz, and the duration of induction heating is set to 5s. The mixture of solder powder and flux is evenly sprayed onto the rotating heating wire through the feeding part, and the rotation speed is maintained at 70r / min to feed the heating wire layer by layer for brazing.

[0103] S5. Welding is completed: After stopping heating, the heated welding wire is obtained after cooling. Example 3

[0104] This embodiment uses the present invention as Figure 1 The welding method shown is for welding a heating wire with a diameter of 5mm and a flat strip thickness of 4mm. The specific steps are as follows:

[0105] S1. Preprocessing:

[0106] (7) Select a heating wire made of nickel-chromium alloy with a diameter of 5 mm and a flat strip thickness of 4 mm;

[0107] (8) Grinding the surface of the heating wire using a grinding wheel, pre-processing the brazing side of several heating wires into a truncated cone shape, and dividing the brazing side into a first welding surface and a second welding surface;

[0108] (9) The surface of the first weld surface is rough. Use a polishing disc to polish the second weld surface until the surface is smooth.

[0109] S2. First welding:

[0110] (9) Fix the two heating wires with a vertical clamp, place a 1.2 mm thick solder sheet on the first welding surface of the heating wire supported by the second clamp, and the solder sheet is ERNiCrMo-4. Adjust the minimum distance D between the induction heating parts to 5.3 mm;

[0111] (10) After nitrogen was introduced for 8 seconds, the induction heating unit was activated, the induction heating current was set to 530 A, the current frequency was set to 82 Hz, and the duration of induction heating was set to 6 seconds;

[0112] (11) Keep the vertical clamp on one side stationary and control the vertical clamp on the other side to rotate for friction welding. The rotation speed is 859 r / min, the friction pressure is 3.1 MPa, the friction time is 0.8 s, and the forging pressure is 70 MPa.

[0113] (12) After controlling the rotation of the single-sided vertical clamp for friction welding, stop heating.

[0114] S3. Surface treatment:

[0115] (7) Fix the heating wire obtained after the first welding in S2 with a horizontal clamp, activate the induction heating part for 6 seconds, and connect the oxygen pump to the ventilation part to introduce oxygen into the equipment. The oxygen concentration introduced is 18 ppm;

[0116] (8) Control the vertical clamps on both sides to drive the heating wire to rotate in the same direction at a speed of 91 r / min;

[0117] (9) After the rotation of the bidirectional horizontal clamp stops, a thin oxide layer is formed on the surface of the heating wire.

[0118] S4, secondary welding:

[0119] (9) The solder used in the secondary welding is a silver-copper alloy, which is a mixture of AgCu20 and AgCu28, where the doping concentration of AgCu28 is 2.1wt%;

[0120] (10) NaF is selected as the flux used for secondary welding;

[0121] (11) Add solder powder to flux, with the mass ratio of solder powder to flux being 51:21; grind the mixture into a solder-flux mixed powder with a particle size of 65 μm;

[0122] (12) After nitrogen was introduced for 8 seconds, the induction heating part was activated, and the induction heating current was set to 700A, the current frequency was set to 60Hz, and the duration of induction heating was set to 6 seconds. A mixture of solder powder and flux was evenly sprayed onto the rotating heating wire through the feeding part, and the rotation speed was maintained at 75r / min to feed the heating wire layer by layer for brazing.

[0123] S5. Welding is completed: After stopping heating, the heated welding wire is obtained after cooling. Example 4

[0124] This embodiment provides a protector heating wire welding device such as Figure 2 As shown, it specifically includes: an equipment body, and an induction heating part, a working part and a loading part arranged inside the equipment body;

[0125] The main body of the equipment includes: a welding chamber, an operating door arranged on the welding chamber, an observation window arranged on the operating door, and a plurality of universal wheels arranged at the bottom of the main body of the equipment; Figure 3 shows a schematic diagram of the overall cross-sectional structure of this embodiment;

[0126] like Figure 4 The working part shown includes: a vertical clamping member and a horizontal clamping member arranged inside the main body of the device, a rotating member and a telescopic member arranged on the vertical clamping member and the horizontal clamping member, and a ventilation member arranged inside the main body of the device; the ventilation member is connected to an inert gas pump and an oxygen pump arranged outside;

[0127] The induction heating part includes: a first conductive part and a second conductive part arranged opposite to each other, and a plurality of high-frequency devices electrically connected to the first conductive part and the second conductive part; the first conductive part and the second conductive part are both conductive loops; the specific arrangement is as follows Figure 5 As shown;

[0128] The vertical clamping member includes a first clamping member and a second clamping member respectively arranged on the top inner wall and the bottom inner wall of the equipment body; the horizontal clamping member includes a third clamping member and a fourth clamping member respectively arranged on both sides of the inner wall of the equipment body. The layout positions of the vertical clamping member and the horizontal clamping member are as follows: Figure 6 As shown;

[0129] The feeding part includes: a plurality of feeding pipes arranged on both sides of the vertical clamping member, and a feeding nozzle arranged on one side of the feeding pipe, such as Figure 7 As shown; wherein, the diameter of the feeding nozzle is 0.3~0.5mm.

[0130] Comparative Example 1

[0131] However, under the action of the alternating electromagnetic field, the current distribution inside the part is uneven, and the current is concentrated in a thin layer on the surface of the part. The closer to the surface of the part, the greater the current density, the higher the frequency, and the smaller the current penetration depth. Although the surface layer is heated rapidly, the heated thickness becomes thinner. The interior of the part can only be heated by heat conduction from the surface layer to the inside, resulting in the skin effect.

[0132] In addition, the solder usually has a certain thickness during induction welding. However, if the heating is insufficient, only the surface of the solder will melt, while the liquid solder will not be completely formed inside, resulting in uneven heating and pores inside the solder. These pores will affect the strength and sealing performance during brazing.

[0133] In order to investigate the comparative effect of the heating wire welding method of the present application and the traditional induction brazing, Example 1 is selected for comparison. The heating wire used in Comparative Example 1 is exactly the same as that in Example 1, except that Comparative Example 1 only uses induction brazing to weld the heating wire. The specific steps are as follows:

[0134] S1. Fix two heating wires and coat the opposite surfaces of the two heating wires with a mixture of AgCu3 and AgCu5, where the doping concentration of AgCu5 is 2.8wt%;

[0135] S2. After nitrogen is introduced for 7 seconds, the induction heating current is set to 550 A, the current frequency is set to 50 Hz, the induction heating duration is set to 5 seconds, and the heating wire is brazed.

[0136] S3. After stopping heating, the heating wire is cooled to obtain the completed welding wire.

[0137] Comparative Example 2

[0138] In order to investigate the comparative effect of the heating wire welding method of the present application and traditional friction brazing, Example 1 is selected for comparison. The heating wire used in Comparative Example 2 is exactly the same as that in Example 1, except that Comparative Example 2 only uses friction welding to weld the heating wire. The specific steps are as follows:

[0139] S1. Fix two heating wires and apply ENiCrMo-3 solder on the opposite sides of the two heating wires;

[0140] S2. Set the rotation speed to 750 r / min, the friction pressure to 2 MPa, the friction time to 0.3 s, and the forging pressure to 63 MPa for friction welding.

[0141] S3. Get the welded heating wire.

[0142] Test Example 1

[0143] Mechanical properties tests, corrosion resistance tests and service life tests were performed on Examples 1 to 3 and Comparative Examples 1 and 2 using a universal testing machine. The test results are shown in the following table:

[0144] Table 1 Mechanical properties, corrosion resistance and service life test results

[0145]

[0146] It can be seen from the above test data that the present invention achieves the effect of improving the brazing strength by combining friction welding and induction welding, and as the diameter of the heating wire and the thickness of the flat strip increase, the tensile strength and elongation at break also increase accordingly; and through two weldings, the corrosion resistance effect is also improved, and the hardness is also enhanced synchronously, further increasing the service life; compared with the control example 1 which only uses induction brazing and the control example 2 which only uses friction welding, the present invention significantly improves the mechanical properties and corrosion resistance of the heating wire.

[0147] The above description is based on the ideal embodiment of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the content of the specification and must be determined according to the scope of the claims.

Claims

1. A method for welding a protector heating wire, characterized in that: The following steps are involved: S1. Pretreatment: Pretreatment of the soldering sides of the plurality of heating wires into a truncated cone shape, and dividing the soldering sides into a first soldering surface and a second soldering surface; mechanical treatment until the first soldering surface has a rough surface and the second soldering surface has a smooth surface; S2. First welding: Fix several heating wires with vertical clamps, place a thin sheet of solder on the first welding surface, introduce inert gas and activate the induction heating part, and control the rotation of the single-side vertical clamp to perform friction welding, then stop heating; S3. Surface treatment: The heating wire obtained after the first welding in S2 is fixed with a horizontal clamp, the induction heating part is activated, oxygen is introduced, and the bidirectional horizontal clamp is controlled to rotate to form a thin oxide layer on the surface of the heating wire. The oxide layer is used to treat the second weld surface into a rough weld surface; S4, secondary welding: Inert gas is introduced, and a mixture of solder powder and flux is evenly sprayed onto the rotating heating wire through the feeding part, and the heating wire is brazed layer by layer; S5, welding is completed: after stopping heating, the heating wire is cooled to obtain the completed welding wire; In said S2, the specific steps of activating the induction heating part after introducing the inert gas are as follows: S21. Connect an inert gas pump to the ventilation part to introduce inert gas into the equipment for 7-8 seconds, then activate the induction heating part, set the induction heating current to 300-700A, the current frequency to 50-100Hz, and the induction heating duration to 5-6 seconds; S22, keeping one side of the vertical clamp stationary, controlling the other side of the vertical clamp to rotate for friction welding, the rotation speed is 600-1100 r / min, the friction pressure is 1.2-2.5 MPa, the friction time is 0.2-0.5 s, and the upset pressure is 55-67 MPa; In said S2, when a solder sheet is placed on the first welding surface, the thickness of said solder sheet is not greater than 1 mm; said solder sheet is a nickel-based alloy, including at least one of ENiCrMo-3, ERNiCrMo-11, ERCuNi, and ERNiCrMo-4; In said S3, introducing oxygen and controlling the rotation of the bidirectional horizontal clamp specifically includes the following steps: S31, connecting an oxygen pump to the ventilation part to introduce oxygen into the device; the concentration of the introduced oxygen is 14-20 ppm, and the introduced oxygen concentration is used to completely consume the introduced oxygen after the oxide layer is formed; S32, control the horizontal clamps on both sides to drive the heating wire to rotate in the same direction, with a rotation speed of 65-130r / min; In said S4, the steps of preparing the mixture of solder powder and flux are specifically as follows: S41. The solder used in the secondary soldering is a silver-copper alloy, which is at least one of Ag99.95, AgCu3, AgCu5, AgCu7.5, AgCu10, AgCu15, AgCu20, AgCu28, and AgCu50; S42. Select a flux to be used in secondary welding, which is one of NaF, NH4Cl and KF; S43, adding solder powder to the flux, with the mass ratio of solder powder to flux being 45-55:15-25; and grinding the mixture into a solder-flux mixed powder with a particle size of 55-90 μm.

2. The method for welding a protector heating wire according to claim 1, wherein: The inert gas is one or more of helium, neon, argon, krypton, xenon and radon.

3. A protector heating wire welding device, based on a protector heating wire welding method according to any one of claims 1 to 2, comprising: The device body, and the induction heating part, working part and feeding part arranged inside the device body are characterized in that: The equipment body includes: a welding chamber, an operating door provided on the welding chamber, an observation window provided on the operating door, and a plurality of universal wheels provided on the bottom of the equipment body; The induction heating part includes: a first conductive part and a second conductive part arranged opposite to each other, and a plurality of high-frequency devices electrically connected to the first conductive part and the second conductive part; the first conductive part and the second conductive part are both conductive loops; The working part includes: a vertical clamping member and a horizontal clamping member arranged inside the main body of the device, a rotating member and a telescopic member arranged on the vertical clamping member and the horizontal clamping member, and a ventilation member arranged inside the main body of the device; the ventilation member is connected to an inert gas pump and an oxygen pump arranged outside; The feeding part includes: a plurality of feeding pipes arranged on both sides of the vertical clamping piece, and a feeding spray hole arranged on one side of the feeding pipe.

4. The protector heating wire welding device according to claim 3, characterized in that: The vertical clamping member includes a first clamping member and a second clamping member respectively arranged on the top inner wall and the bottom inner wall of the equipment body; the horizontal clamping member includes a third clamping member and a fourth clamping member respectively arranged on both sides of the inner wall of the equipment body.

5. The protector heating wire welding device according to claim 3, characterized in that: The diameter of the feeding nozzle is 0.3-0.5 mm.

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