Preparation method and device for composite welding wire containing flux core

Abstract

The invention discloses a preparation method and device of a flux-cored composite welding wire, and relates to the technical field of brazing, in particular to the preparation method of the flux-cored composite welding wire, which comprises the following steps: preparing a superplastic welded pipe by adopting a Zn-Al superplastic alloy; welding flux metal powder and brazing flux are mixed, and a flux core material is prepared; and the superplastic welded pipe is heated to the superplastic deformation temperature, ultrasonic vibration is conducted on the superplastic welded pipe, thermoplastic drawing is conducted on the superplastic welded pipe, meanwhile, the flux core material is continuously poured into an inner cavity of the superplastic welded pipe, and the composite welding wire containing the flux core is obtained. According to the method, the superplastic alloy is used as a welded pipe skin material for temperature-controlled drawing, and the superplastic alloy has ultrahigh elongation, so that the processing and forming performance of the welded pipe skin is excellent, and the drawing frequency required for forming of the flux-cored wire can be effectively reduced. And meanwhile, the flux core material is synchronously filled in the thermoplastic drawing process, so that overflowing and pervading of toxic dust are reduced, the process is simple, and automatic and efficient filling can be adopted.

Description

Technical Field

[0001] The invention relates to the technical field of brazing, and in particular to a method and a device for preparing a composite welding wire containing a flux core. Background Art

[0002] Welding wire is a key material in the welding process, mainly including solid welding wire and flux-cored welding wire. The flux-cored welding wire is filled with a specific flux to form a "tube-like" structure. The flux contains various alloy elements and auxiliary materials, which can improve the metallurgical and mechanical properties during the welding process.

[0003] The melting point of Zn-Al solder alloy is in the range of 382-500℃ depending on the aluminum content. The plastic strength and wettability of the solder also change due to the change of aluminum content. Therefore, the preparation of Zn-Al solder that can flexibly adjust the aluminum content in the solder formula has good application prospects. In the traditional method of preparing flux-cored welding rods, the proportions of Zn and Al are first calculated and prepared when the solder metal powder is smelted, and a long and thin welding pipe is formed by continuous casting and extrusion. The solder is added to the slender welding pipe by manual powder loading, and then the diameter is changed and drawn multiple times to form flux-cored welding wires of different specifications. However, during the manual powder loading process, toxic dust is easily spilled and diffused, which is not conducive to worker safety and environmental protection; and the number of drawing forming times is large, the drawing die expenditure is high, the process is complicated, and it takes a long time.

[0004] For example, in a method for preparing a composite solder flux-cored aluminum welding wire in patent CN103612026A, a composite aluminum alloy is rolled into a composite alloy strip by a rolling mill, and the composite strip is thinned to 0.3-0.6 mm, and the strip width is 9-12 mm; the composite alloy strip is rolled into a U shape; after adding a flux core into the U-shaped groove of the composite alloy strip, the composite alloy strip is rolled into an O shape, and the diameter is reduced to 2.4-3.0 mm; the diameter is further reduced to make a composite solder flux-cored aluminum welding wire with a diameter of 1.0-3.0 mm; the outer skin in the form of a composite strip replaces the outer skin in the form of a traditional alloy, thereby improving the processing performance of the composite solder flux-cored welding wire. However, the manufacturing process of the flux-cored welding wire requires multiple diameter reduction treatments to achieve the specifications of a specific flux-cored welding wire, and the production efficiency is low. In addition, adding a flux core in the U-shaped groove easily leads to the overflow and diffusion of toxic dust, and the production environment is poor. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects and shortcomings of the prior art and provide a method for preparing a composite welding wire containing a flux core, which can reduce the number of drawing and forming times, achieve efficient filling of flux powder, and improve the welding performance of the welding wire.

[0006] Another object of the present invention is to provide a device for preparing a composite welding wire containing a flux core.

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] The present invention provides a method for preparing a composite welding wire containing a flux core, comprising the following steps:

[0009] S1, using Zn-Al superplastic alloy to prepare superplastic welded pipe;

[0010] S2, mixing solder metal powder and brazing flux to prepare a flux core material;

[0011] S3, heating the superplastic welded pipe to a superplastic deformation temperature, ultrasonically vibrating the superplastic welded pipe, thermoplastically drawing the superplastic welded pipe, and continuously pouring the flux-cored material into the inner cavity of the superplastic welded pipe during the drawing process, so as to obtain a flux-cored composite welding wire.

[0012] The method for preparing a composite welding wire containing a flux core of the present invention uses a superplastic alloy as the outer skin material of the weld pipe for temperature-controlled drawing. The superplastic alloy has an ultra-high elongation, which makes the outer skin of the weld pipe have excellent processing and forming properties, and can be drawn in a large diameter change range, effectively reducing the number of drawing times required for the forming of the flux-cored welding wire. At the same time, the flux core material is filled synchronously during the thermoplastic drawing process to reduce the overflow and diffusion of toxic dust, and the process is simple, and automated and efficient filling can be used. Furthermore, the present invention uses a specific superplastic alloy as the outer skin material of the weld pipe, and by regulating the solder metal powder component in the flux core material, the welding wire is melted during welding to form the required solder component, thereby achieving the effect of flexibly adjusting the aluminum content in the solder.

[0013] When the deformation amount is large during the drawing process, the friction and resistance between the mold and the workpiece increase, which not only makes deformation difficult, but also causes the roughness of the inner surface of the formed tube cavity to be too large. When the flux is directly filled, it is easy to cause powder jamming problems in local areas, affecting the welding strength and effect. In the present invention, after ultrasonic treatment is used in the superplastic material drawing process, the outer surface of the mold core and the inner wall of the solder tube cavity are separated and touched in a pulsed manner, so that the outer wall of the mold core and the inner wall of the solder are scraped at high frequency, thereby improving the surface quality of the inner wall of the tube cavity.

[0014] The superplastic alloys of the present invention refer to metal materials having superplasticity, wherein the superplasticity refers to a phenomenon in which the elongation exceeds 100%.

[0015] The superplastic alloy of the present invention can achieve a diameter variation range of not less than 22 mm during drawing, for example, a through pipe with an outer diameter of Φ30 mm can be reduced in diameter by drawing into a pipe with an outer diameter of Φ8 mm.

[0016] In some embodiments, in step S1, the Zn-Al superplastic alloy is ZnAl5 and / or ZnAl22. The ZnAl5 or ZnAl22 superplastic alloy has an elongation of more than 2500% at 200-300°C and excellent drawing processing performance.

[0017] In some embodiments, step S1 specifically includes: plastically deforming the Zn-Al superplastic alloy at 250-300°C, with the plastic deformation amount ≥ 80%, and annealing at 290-310°C for 1.5-3h to obtain a superplastic welded pipe. Preferably, the plastic deformation amount is 80-120%.

[0018] In some embodiments, in step S2, the solder metal powder is at least one of Zn powder, Al powder, Zn-based master alloy powder or Al-based master alloy powder. Preferably, the content of Al and Zn in the solder metal powder is not less than 85wt%, more preferably, the content of Al and Zn is not less than 90wt%.

[0019] Preferably, the Zn-based master alloy or the Al-based master alloy includes but is not limited to a Zn-Al master alloy, a Zn-Mg master alloy or an Al-Mg master alloy.

[0020] Optionally, the Zn-Al master alloy includes but is not limited to ZnAl2, ZnAl10, ZnAl15, ZnAl20, ZnAl30, and ZnAl50.

[0021] Optionally, the Zn-Mg master alloy includes ZnMg2.

[0022] Optionally, the Al-Mg master alloy includes AlMg2.

[0023] In some embodiments, in step S2, the brazing flux is selected from aluminum-based brazing fluxes, including but not limited to cesium fluoroaluminate brazing flux (CsF-AlF3-KF) and / or potassium fluoroaluminate brazing flux.

[0024] In some embodiments, in step S2, the mass ratio of the Zn-Al superplastic alloy to the solder metal powder is (1.5-22):1.

[0025] In some embodiments, in step S2, the ratio of the total mass of the Zn-Al superplastic alloy and the solder metal powder to the mass of the flux is (8-9):(1-2); preferably (8.5-8.8):(1.2-1.5).

[0026] In some embodiments, in step S3, the superplastic welded pipe is thermoplastically drawn while continuously pouring the flux-cored material into the inner cavity of the superplastic welded pipe, specifically comprising: thermoplastically forming the superplastic welded pipe in a mold whose outer diameter gradually decreases along the axial direction, so that a drawing portion with a smaller outer diameter is formed on one side of the superplastic welded pipe, the drawing portion of the superplastic welded pipe is drawn in a direction away from the mold, and the flux-cored material is poured into the inner cavity of the superplastic welded pipe, and during the drawing process, the pouring terminal of the flux-cored material moves synchronously with the drawing portion along the drawing direction.

[0027] Optionally, the pulling speed is 20-30 mm / min.

[0028] In some embodiments, in step S3, the superplastic deformation temperature is 250-300°C.

[0029] In some embodiments, in step S3, the frequency of the ultrasound is 16-22 kHz, and the power is 300-800 W.

[0030] A preparation device for a composite welding wire containing a flux core, comprising a drawing die module, an ultrasonic module, a temperature control module and a powder spraying and traction module;

[0031] The drawing die module is used for thermoplastic forming of the superplastic welded pipe, so that the outer diameter of the superplastic welded pipe is reduced to a preset value;

[0032] The ultrasonic module is connected to the drawing die module and is used for ultrasonic vibration of the superplastic welded pipe;

[0033] The temperature control module is arranged at the front end of the drawing die module, and is used to heat the superplastic welded pipe to a preset temperature so that the superplastic welded pipe has superplastic deformation;

[0034] The powder spraying and pulling module is arranged at the rear end of the drawing die module, and comprises a horizontally movable welding pipe clamp and a flux core material nozzle, and is used for thermoplastic drawing of the superplastic welding pipe and pouring flux core material into the inner cavity of the superplastic welding pipe.

[0035] The composite welding wire preparation device containing a flux core of the present invention is used to prepare composite solder, and the high melting point metal or reinforcement is automatically filled into the hollow solder tube in the form of powder, and then the metal-based composite solder wire is obtained through multiple diameter reduction treatments. The traditional method is to add high melting point metal elements or reinforcements during smelting and casting to make ingots. Since the composition of the metal outer skin has changed, its plasticity and strength have also changed. The rheological behavior of the metal has changed during deformation processing, and it is easy to break, crack, and composite problems. It is necessary to improve the conventional molding processing technology, such as extrusion temperature, extrusion speed, extrusion force, etc. The cost of experimental research is high, and it is difficult to flexibly adjust the aluminum content in the solder formula.

[0036] In some embodiments, the drawing die module includes an outer die and a die core, the inner diameter of the outer die changes from large to small along the axial direction and is used to connect with the outer wall of the superplastic welded pipe, and the die core is used to connect with the inner wall of the superplastic welded pipe.

[0037] In some embodiments, the ultrasonic module includes an ultrasonic generator and a frequency modulator, a transducer, a horn and a work head connected in sequence. When the deformation of the superplastic welded pipe workpiece is large, the friction and resistance between the mold and the workpiece increase, making deformation difficult, and the roughness of the inner surface of the tube cavity is too large. After using ultrasound, the outer surface of the mold core and the inner wall of the solder tube cavity are separated and touched in a pulsed manner, so that the outer wall of the mold core and the inner wall of the solder are scraped at high frequency, thereby improving the surface quality of the inner wall of the tube cavity.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention provides a method for preparing a composite welding wire containing a flux core, wherein a superplastic alloy is used as a welding pipe outer skin material for temperature-controlled drawing, and the superplastic alloy has an ultra-high elongation, so that the outer skin of the welding pipe has excellent processing and forming performance, and can effectively reduce the number of drawing times required for the forming of the flux-cored welding wire. At the same time, the flux core material is synchronously filled during the thermoplastic drawing process, so as to reduce the overflow and diffusion of toxic dust, and the process is simple, and automatic and efficient filling can be adopted.

[0040] Furthermore, the present invention adopts a specific superplastic alloy as the outer skin material of the welded pipe, and controls the solder metal powder components in the flux core material so that the welding wire melts during welding to form the required solder composition, thereby achieving the effect of flexibly adjusting the aluminum content in the solder. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the superplastic welded pipe forming process of Example 1 of the present invention.

[0042] Figure 2 This is a schematic diagram of the superplastic welded pipe forming process flow of Example 2 of the present invention.

[0043] Figure 3 This is a schematic diagram of the superplastic welded pipe forming process flow of Example 3 of the present invention.

[0044] Figure 4 The SEM and elemental analysis diagrams of the welding interface of the flux-cored welding wire and aluminum sheet brazing (brazing temperature 450° C.) in Example 1 of the present invention. Figure 4 The lower and middle parts are aluminum alloy, and the upper part is solder.

[0045] Figure 5The SEM and elemental analysis diagrams of the welding interface of the flux-cored welding wire and aluminum sheet brazing (brazing temperature 450° C.) according to Example 2 of the present invention. Figure 5 The lower and middle parts are aluminum alloy, and the upper part is solder.

[0046] Figure 6 The SEM and elemental analysis diagrams of the welding interface of the flux-cored welding wire and aluminum sheet brazing (brazing temperature 450° C.) according to Example 3 of the present invention. Figure 6 The lower and middle parts are aluminum alloy, and the upper part is solder.

[0047] Figure 7 The SEM and elemental analysis diagrams of the welding interface of the flux-cored welding wire and aluminum sheet brazing (brazing temperature 490° C.) according to Example 4 of the present invention. Figure 7 The lower and middle parts are aluminum alloy, and the upper part is solder.

[0048] Figure 8 This is a morphology diagram of the welding interface of the flux-cored welding wire of comparative example 1 of the present invention and the aluminum sheet brazing (brazing temperature 450° C.). Figure 8 The lower and middle parts are aluminum alloy, and the upper part is solder.

[0049] Among them, 1. alloy melting furnace; 2. crystallizer; 3. support wheel; 4. roller; 401. first extrusion die; 402. second extrusion die; 403. first roller; 404. second roller; 5. blank; 51. O-shaped tube; 6. forging head; 7. forging die; 8. tube blank; 81. superplastic tube; 82. solder tube; 91. ultrasonic generating and frequency modulation device; 92. ultrasonic transducer; 93. amplitude transformer; 94. working fixed head; 10. electromagnetic heater; 11. ejector rod; 12. mold core; 13. drawing outer mold; 14. core powder; 15. fixture; 16. air compressor; 17. high-pressure nozzle; 18. powder pump. DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0051] The raw materials used in the following examples and comparative examples are as follows:

[0052] AlMg2 alloy powder: Beijing Juguang Evonik Technology Co., Ltd.

[0053] ZnMg2 alloy powder: Hebei Chaoyue Metal Alloy Materials Co., Ltd.

[0054] ZnAl20: Hebei Chaoyue Metal Alloy Materials Co., Ltd.

[0055] Cesium fluoroaluminate brazing flux: Wuhan Shuer Biotechnology Co., Ltd.

[0056] Example 1

[0057] A ZnAl8-0.03Mg alloy flux-cored welding rod, wherein the welding material comprises, by weight percentage, 8% Al, 0.03% Mg and the balance Zn.

[0058] ZnAl8 is one of the common high-strength zinc-aluminum alloys. Trace amounts of Mg can improve the wetting properties of the solder. When the mass percentage of Al is 8%, it is a Zn-Al hypereutectic alloy.

[0059] A method for preparing a composite welding wire containing a flux core, such as Figure 1 As shown, the following steps are included:

[0060] (1) Preparation of ZnAl5 superplastic alloy tube: Mix and prepare the materials according to the mass ratio of various metal elements in the alloy ZnAl5 (Al 5%), heat them in a smelting furnace 1 to 720°C until they are molten, keep them warm for 25 minutes, and pour them into a crystallizer 2 and a mold after slagging. Use a continuous casting and rolling method to form a plate-shaped billet 5 with a thickness of 15 mm at a rolling speed of 25 mm / min, and cut the billet 5 into circular plates. The continuous casting and rolling method specifically includes that after the crystallizer 2 discharges the material, the material is supported and transported by a support wheel 3, and the material is rolled and deformed under the action of two rollers 4 to obtain a plate-shaped billet 5 with a thickness of 15 mm.

[0061] The circular plate blank 5 is subjected to hot forging at 250°C, the hot forging is die forging, the forging speed is 10mm / min, the outer diameter of the forging head 6 is Φ20mm, the diameter of the concave die of the forging die 7 is Φ30mm, and a cylinder with an outer diameter of Φ30mm and an inner diameter of Φ20mm with a cover at one end can be obtained by die forging. The covers at the head and bottom are removed and the tube blanks 8 are divided into tube blanks 8 with a length of 150mm and a mass of about 400g.

[0062] The tube blank 8 is annealed, and the annealing process is: heating at 300° C. and keeping the temperature for 2 hours, and then cooling in the furnace.

[0063] (2) Preparation of core powder 14: The intermediate alloy powder and the brazing agent are fully mixed; and then the mixed powder is loaded into a powder pump container in the powder spraying traction module.

[0064] The intermediate alloy powder is 100.09 grams of ZnAl20 and 6.09 grams of AlMg2, and the flux is 80 grams of cesium fluoroaluminate flux.

[0065] (3) Drawing and powder filling: The tube blank 8 is subjected to thermoplastic drawing and powder filling processing, and the equipment used is a drawing-powder filling equipment.

[0066] The drawing-powder filling equipment comprises a drawing die module, an ultrasonic module, a temperature control module and a powder spraying and traction module.

[0067] The drawing die module includes a drawing outer die 13 and a die core 12, the aperture of the drawing outer die 13 is Φ8.01mm, the outer diameter of the die core 12 is Φ6.00mm, the tube blank 8 is heated to form a superplastic tube 81, and after passing through the drawing outer die 13 and the die core 12, a solder tube 82 is finally formed; its outer diameter is Φ8mm and its inner diameter is Φ6.00mm.

[0068] The ultrasonic module includes: an ultrasonic generating and frequency modulation device 91, an ultrasonic transducer 92, an horn 93, and a working fixed head 94, which are connected in sequence. The ultrasonic working head is driven by the ultrasonic generating and frequency modulation device 91, and can convert electrical energy into mechanical energy through the ultrasonic transducer 92, change the amplitude through the horn 93, and transmit the mechanical oscillation to the working fixed head 94. The working fixed head 94 is connected to the mold core 12 through the top rod 11. The ultrasonic frequency of the working fixed head is 20kHz and the power is 500W.

[0069] The temperature regulating module is an electromagnetic heater 10, which is arranged at the front end of the drawing die. The temperature regulating device is an induction heating system. When the temperature is controlled at 250°C, the superplastic pipe 81 maintains superplasticity.

[0070] The powder spraying traction module includes a clamp 15 and a flux core material pouring structure. The clamp 15 is used to clamp the weld pipe and apply traction force to draw and form it at a speed of 25 mm / min. The clamp 15 is connected to a high-pressure nozzle 17B at the tail of the traction member, and the flux core powder 14 prepared in step (2) is sprayed into the weld pipe at a high speed by the high-pressure nozzle 17, wherein the high-pressure nozzle 17 is respectively connected to an air compressor 16 and a powder pump 18;

[0071] The clamp 15 and the high-pressure nozzle 17B are pulled along the drawing direction and move to the right together with the tail of the welded pipe. When the welded pipe becomes longer during the drawing, the flux-cored powder 14 is continuously sprayed into the lumen until it is filled, forming a flux-cored welding wire with an outer diameter of 8 mm and an inner diameter of 6 mm.

[0072] Example 2

[0073] A ZnAl10 alloy flux-cored welding rod, wherein the solder comprises, by weight percentage, 10% Al and the remainder Zn. When the mass percentage of Al is 10%, it is a Zn-Al hypereutectic alloy.

[0074] A method for preparing a composite welding wire containing a flux core, such as Figure 2 As shown, the following steps are included:

[0075] (1) Preparation of ZnAl5 superplastic alloy tube: The various metal elements in the alloy ZnAl5 are mixed and proportioned according to their mass ratio (Al 5%), and the mixture is placed in a smelting furnace 1 and heated to 720°C until it is molten. The mixture is kept warm for 25 minutes, and after slagging, it is poured into a crystallizer 2 and a first extrusion die 401 to form a cylindrical rod with a diameter of Φ100 mm. When the rod is cooled to 300°C, it is extruded using a second extrusion die 402 to extrude the casting into a through tube with an outer diameter of Φ30 mm and an inner diameter of Φ20 mm, and the casting is divided into tube blanks 8 with a length of 150 mm. The weight of each tube blank 8 is 400.35 g.

[0076] The tube blank 8 is annealed, and the annealing process is: heating at 300° C. and keeping the temperature for 2 hours, and then cooling with the furnace to obtain a superplastic tube blank.

[0077] (2) Preparation of core powder 14: The intermediate alloy powder and the brazing agent are fully mixed; and then the mixed powder is loaded into a powder pump container in the powder spraying traction module.

[0078] Wherein, the intermediate alloy powder is 200.175 grams of ZnAl20, and the brazing flux is 105 grams of cesium fluoroaluminate brazing flux.

[0079] (3) Drawing and powder filling: The tube blank 8 is subjected to thermoplastic drawing and powder filling processing, and the equipment used is a drawing-powder filling equipment.

[0080] The drawing-powder filling equipment comprises a drawing die module, an ultrasonic module, a temperature control module and a powder spraying and traction module.

[0081] The drawing die module includes a drawing outer die 13 and a die core 12, the aperture of the drawing outer die 13 is Φ8.01mm, the outer diameter of the die core 12 is Φ6.00mm, the tube blank 8 is heated to form a superplastic tube 81, and after passing through the drawing outer die 13 and the die core 12, a solder tube 82 is finally formed, the outer diameter of which is Φ8mm and the inner diameter is Φ6.00mm.

[0082] The ultrasonic module includes: an ultrasonic generating and frequency modulation device 91, an ultrasonic transducer 92, an horn 93, and a working fixed head 94, which are connected in sequence. The ultrasonic working head is driven by the ultrasonic generating and frequency modulation device 91, and can convert electrical energy into mechanical energy through the ultrasonic transducer 92, change the amplitude through the horn 93, and transmit the mechanical oscillation to the working fixed head 94. The working fixed head 94 is connected to the mold core 12 through the top rod 11. The ultrasonic frequency of the working fixed head is 18kHz and the power is 400W.

[0083] The temperature regulating module is an electromagnetic heater 10, which is arranged at the front end of the drawing die. The temperature regulating device is an induction heating system. When the temperature is controlled at 280°C, the superplastic pipe 81 maintains superplasticity.

[0084] The powder spraying traction module includes a clamp 15 and a flux core material pouring structure. The clamp 15 is used to clamp the weld pipe and apply traction force to draw and form it at a speed of 25 mm / min. The clamp 15 is connected to a high-pressure nozzle 17 at the tail of the traction part, and the flux core powder 14 prepared in step (2) is sprayed into the weld pipe at a high speed by the high-pressure nozzle 17, wherein the high-pressure nozzle 17 is respectively connected to an air compressor 16 and a powder pump 18;

[0085] The clamp 15 and the high-pressure nozzle 17 are pulled along the drawing direction and move to the right together with the tail of the welding pipe. When the welding pipe is drawn longer, the flux core powder 14 is continuously sprayed into the tube cavity until it is filled, forming a flux cored welding wire with an outer diameter of 8 mm and an inner diameter of 6 mm.

[0086] Example 3

[0087] A ZnAl15 alloy flux-cored welding rod, wherein the solder comprises, by weight percentage, 15% Al and the remainder Zn. When the mass percentage of Al is 15%, it is a Zn-Al hypereutectic alloy.

[0088] A method for preparing a composite welding wire containing a flux core, such as Figure 3 As shown, the following steps are included:

[0089] (1) Preparation of ZnAl22 superplastic alloy tube: Mix and prepare the various metal elements in the alloy ZnAl22 according to their mass ratio (Al22%), heat them in a smelting furnace 1 to 720°C until they are molten, keep them warm for 25 minutes, and pour them into a crystallizer 2 and a mold after slagging. When the casting is cooled to 280°C, use a continuous casting and rolling method, and use the first roller 403 and the second roller 404 to roll and deform the casting into a plate-shaped billet 5 with a thickness of 2 mm at a rolling speed of 25 mm / min. The billet 5 is rolled into an O-shaped tube 51 with an outer diameter of Φ8 mm and an inner diameter of Φ6.00 mm; and cut into a tube billet 8 with a length of 150 mm, weighing 353.25 g.

[0090] The tube blank 8 is annealed, and the annealing process is: heating at 300° C. and keeping the temperature for 2 hours, and then cooling with the furnace to obtain a superplastic tube blank.

[0091] (2) Preparation of core powder 14: The intermediate alloy powder and the brazing agent are fully mixed; and then the mixed powder is loaded into a powder pump container in the powder spraying traction module.

[0092] Wherein, the intermediate alloy powder is 164.85 grams of Zn powder, and the brazing agent is 80 grams of cesium fluoroaluminate brazing agent.

[0093] (3) Drawing and powder filling: The tube blank 8 is subjected to thermoplastic drawing and powder filling processing, and the equipment used is a drawing-powder filling equipment.

[0094] The drawing-powder filling equipment comprises a drawing die module, an ultrasonic module, a temperature control module and a powder spraying and traction module.

[0095] The drawing die module includes a drawing outer die 13 and a die core 12, the aperture of the drawing outer die 13 is Φ5.01mm, the outer diameter of the die core 12 is Φ4.00mm, the tube blank 8 is heated to form a superplastic tube 81, and after passing through the drawing outer die 13 and the die core 12, a solder tube 82 is finally formed; its outer diameter is Φ5mm and its inner diameter is Φ4.00mm.

[0096] The ultrasonic module includes: an ultrasonic generating and frequency modulation device 91, an ultrasonic transducer 92, an horn 93, and a working fixed head 94, which are connected in sequence. The ultrasonic working head is driven by the ultrasonic generating and frequency modulation device 91, and can convert electrical energy into mechanical energy through the ultrasonic transducer 92, change the amplitude through the horn 93, and transmit the mechanical oscillation to the working fixed head 94. The working fixed head 94 is connected to the mold core 12 through the top rod 11. The ultrasonic frequency of the working fixed head is 20kHz and the power is 800W.

[0097] The temperature regulating module is an electromagnetic heater 10, which is arranged at the front end of the drawing die. The temperature regulating device is an induction heating system. When the temperature is controlled at 280°C, the superplastic pipe 81 maintains superplasticity.

[0098] The powder spraying traction module includes a clamp 15 and a flux core material infusion structure, and the clamp 15 is used to clamp the weld pipe and apply traction force to draw and form at a speed of 25mm / min. The clamp 15 is connected to the high-pressure nozzle 17B at the tail of the traction member, and the flux core powder 14 prepared in step (2) is sprayed into the weld pipe at high speed by the high-pressure nozzle 17, wherein the high-pressure nozzle 17 is respectively connected to the air compressor 16 and the powder pump 18; the clamp 15 and the high-pressure nozzle 17 are pulled together with the tail of the weld pipe along the drawing direction and move to the right, and when the weld pipe is drawn and lengthened, the flux core powder 14 is also continuously sprayed into the tube cavity until it is filled, forming a flux cored welding wire with an outer diameter of 5mm and an inner diameter of 4mm.

[0099] Example 4

[0100] A ZnAl22Mg0.1 alloy flux-cored welding rod, wherein the solder comprises, by weight percentage, 22% Al, 0.1% Mg, and the remainder Zn. When the mass percentage of Al is 22%, it is a Zn-Al hypereutectic alloy.

[0101] A method for preparing a composite welding wire containing a flux core, such as Figure 3 As shown, the following steps are included:

[0102] (1) Preparation of ZnAl22 superplastic alloy tube: Same as Example 3.

[0103] (2) Preparation of core powder 14: The intermediate alloy powder and the brazing agent are fully mixed; and then the mixed powder is loaded into a powder pump container in the powder spraying traction module.

[0104] Wherein, the intermediate alloy powder is 18.83 grams of ZnMg2 powder, and the brazing agent is 62 grams of cesium fluoroaluminate brazing agent.

[0105] (3) Drawing and powder filling: The ZnAl22 superplastic tube blank is subjected to thermoplastic drawing and powder filling processing, and the equipment used is drawing-powder filling equipment.

[0106] The drawing-powder filling equipment comprises a drawing die module, an ultrasonic module, a temperature control module and a powder spraying and traction module.

[0107] The drawing die module includes a drawing outer die 13 and a die core 12, the aperture of the drawing outer die 13 is Φ8.01mm, the outer diameter of the die core 12 is Φ6.00mm, the tube blank 8 is heated to form a superplastic tube 81, and after passing through the drawing outer die 13 and the die core 12, a solder tube 82 is finally formed, with an outer diameter of Φ8mm and an inner diameter of Φ6.00mm.

[0108] The ultrasonic module includes: an ultrasonic generating and frequency modulation device 91, an ultrasonic transducer 92, an horn 93, and a working fixed head 94, which are connected in sequence. The ultrasonic working head is driven by the ultrasonic generating and frequency modulation device 91, and can convert electrical energy into mechanical energy through the ultrasonic transducer 92, change the amplitude through the horn 93, and transmit the mechanical oscillation to the working fixed head 94. The working fixed head 94 is connected to the mold core 12 through the top rod 11. The ultrasonic frequency of the working fixed head is 18kHz and the power is 400W.

[0109] The temperature regulating module is an electromagnetic heater 10, which is arranged at the front end of the drawing die. The temperature regulating device is an induction heating system. When the temperature is controlled at 280°C, the superplastic pipe 81 maintains superplasticity.

[0110] The powder spraying traction module includes a clamp 15 and a flux core material infusion structure, wherein the clamp 15 is used to clamp the weld pipe and apply traction force, and draw the weld pipe at a speed of 25 mm / min. The clamp 15 is connected to a high-pressure nozzle 17 at the tail of the traction member, and the flux core powder 14 prepared in step (2) is sprayed into the weld pipe at a high speed by the high-pressure nozzle 17, wherein the high-pressure nozzle 17 is respectively connected to an air compressor 16 and a powder pump 18; the clamp 15 and the high-pressure nozzle 17 are pulled together with the tail of the weld pipe along the drawing direction and move to the right, and when the weld pipe is drawn and lengthened, the flux core powder 14 is also continuously sprayed into the lumen until it is filled, forming a flux cored welding wire with an outer diameter of 8 mm and an inner diameter of 6 mm.

[0111] Comparative Example 1

[0112] A method for preparing a composite welding wire containing a flux core is different from that of Example 3 in that during the preparation process, the ultrasonic module is in a closed state.

[0113] Performance Testing

[0114] 1. SEM characterization

[0115] The flux-cored welding wire of Examples 1-4 was brazed between two aluminum sheets at a brazing temperature of 450-490° C. The welding interface of the weldment was obtained for SEM analysis.

[0116] The welding interface of the flux-cored welding wire of Example 1 (brazing temperature 450° C.) is as follows: Figure 4 It can be seen that there is a continuous metallurgical bonding layer between the aluminum alloy and the solder. When the brazing is heated, aluminum atoms diffuse from the matrix to the solder layer, and zinc atoms diffuse from the solder to the aluminum matrix, thus forming a good welding microscopic interface.

[0117] The welding interface of the flux-cored welding wire of Example 2 (brazing temperature 450° C.) is as follows Figure 5 It can be seen that there is a continuous metallurgical bonding layer between the aluminum alloy and the solder, and a large amount of aluminum elements are detected on the side close to the solder in the welding interface, which proves that when brazing is heated, aluminum atoms diffuse from the matrix to the solder layer, thus forming a good welding microscopic interface.

[0118] The welding interface of the flux-cored welding wire of Example 3 (brazing temperature 450° C.) is as follows: Figure 6 It can be seen that there is a continuous metallurgical bonding layer between the aluminum alloy and the solder. When the brazing is heated, aluminum atoms diffuse from the matrix to the solder layer, and zinc atoms diffuse from the solder to the aluminum matrix, thus forming a good welding microscopic interface.

[0119] The welding interface of the flux-cored welding wire of Example 4 (brazing temperature 490° C.) is as follows Figure 7 It can be seen that there is a continuous metallurgical bonding layer between the aluminum alloy and the solder. When the brazing is heated, aluminum atoms diffuse from the matrix to the solder layer, and zinc atoms diffuse from the solder to the aluminum matrix, thus forming a good welding microscopic interface.

[0120] The welding interface of the flux-cored welding wire of Comparative Example 1 (brazing temperature 450° C.) is as follows Figure 8It can be seen that there is a continuous thick black line between the aluminum alloy and the solder. This black line is the oxide film on the aluminum surface that has not been removed. This is because the mold core is not acted on ultrasonically, making the inner surface of the narrow space rough, causing powder jamming in local areas when filling the flux. When there is no flux during welding, the oxide film on the surface of the aluminum alloy cannot be effectively removed, thus affecting the welding strength and effect.

[0121] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a composite welding wire containing a flux core, characterized in that: The following steps are involved: S1, using Zn-Al superplastic alloy to prepare superplastic welded pipe; S2, mixing solder metal powder and brazing flux to prepare a flux core material; S3, heating the superplastic welded pipe in step S1 to a superplastic deformation temperature, ultrasonically vibrating the superplastic welded pipe, thermoplastically drawing the superplastic welded pipe, and continuously pouring the flux core material in step S2 into the inner cavity of the superplastic welded pipe during the drawing process, so as to obtain a flux-cored composite welding wire.

2. The method for preparing a flux-cored composite welding wire according to claim 1, characterized in that: Step S1 specifically includes: plastically deforming the Zn-Al superplastic alloy at 250-300° C., with the plastic deformation amount being ≥80%, and annealing at 290-310° C. for 1.5-3 hours to obtain a superplastic welded pipe.

3. The method for preparing a flux-cored composite welding wire according to claim 1 or 2, characterized in that: In step S1, the Zn-Al superplastic alloy is ZnAl5 and / or ZnAl22.

4. The method for preparing a flux-cored composite welding wire according to claim 1, characterized in that: In step S2, the solder metal powder is at least one of Zn powder, Al powder, Zn-based master alloy powder or Al-based master alloy powder.

5. The method for preparing a flux-cored composite welding wire according to claim 1, characterized in that: In step S2, the brazing flux is cesium fluoroaluminate brazing flux and / or potassium fluoroaluminate brazing flux.

6. The method for preparing a flux-cored composite welding wire according to claim 1, characterized in that: In step S2, the mass ratio of the Zn-Al superplastic alloy to the solder metal powder is (1.5-22):

1.

7. The method for preparing a flux-cored composite welding wire according to claim 1, characterized in that: In step S2, the ratio of the total mass of the Zn-Al superplastic alloy and the solder metal powder to the mass of the flux is (8-9):(1-2).

8. The method for preparing a flux-cored composite welding wire according to claim 1, characterized in that: In step S3, the superplastic welded pipe is thermoplastically drawn, and the flux-cored material is continuously poured into the inner cavity of the superplastic welded pipe, specifically comprising: thermoplastically forming the superplastic welded pipe in a mold whose outer diameter gradually decreases along the axial direction, so that a drawing portion with a smaller outer diameter is formed on one side of the superplastic welded pipe, the drawing portion of the superplastic welded pipe is drawn in a direction away from the mold, and the flux-cored material is poured into the inner cavity of the superplastic welded pipe. During the drawing process, the pouring terminal of the flux-cored material moves synchronously with the drawing portion along the drawing direction.

9. The method for preparing a flux-cored composite welding wire according to claim 1, characterized in that: In step S3, the frequency of the ultrasound is 16-22 kHz, and the power is 300-800 W.

10. A device for preparing a composite welding wire containing a flux core, characterized in that: It includes a drawing die module, an ultrasonic module, a temperature control module and a powder spraying traction module; The drawing die module is used for thermoplastic forming of the superplastic welded pipe, so that the outer diameter of the superplastic welded pipe is reduced to a preset value; The ultrasonic module is connected to the drawing die module and is used for ultrasonic vibration of the superplastic welded pipe; The temperature control module is arranged at the front end of the drawing die module, and is used to heat the superplastic welded pipe to a preset temperature so that the superplastic welded pipe has superplastic deformation; The powder spraying and pulling module is arranged at the rear end of the drawing die module, and comprises a horizontally movable welding pipe clamp and a flux core material nozzle, and is used for thermoplastic drawing of the superplastic welding pipe and pouring flux core material into the inner cavity of the superplastic welding pipe.

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