Square high-temperature aluminum brazing wire and preparation method thereof

Abstract

The present application provides a square high-temperature aluminum brazing filler metal wire and a preparation method thereof. The preparation method comprises: providing a melted brazing filler metal, the brazing filler metal comprising aluminum and silicon; subjecting the brazing filler metal to silicon modification and refining to obtain a modified brazing filler metal; casting the modified brazing filler metal to obtain an ingot; subjecting the ingot metal to a first hot extrusion treatment multiple times to obtain a round brazing filler metal of a first diameter; subjecting the round brazing filler metal of the first diameter to a second hot extrusion treatment multiple times, subjecting each preset second extrusion treatment to a first annealing treatment to obtain a round brazing filler metal of a second diameter; the second diameter being 0.23-0.28 times the first diameter; subjecting the round brazing filler metal of the second diameter to a cold drawing treatment in a chamfered wire drawing die, subjecting the cold drawing treatment to a second annealing treatment to obtain a square high-temperature aluminum brazing filler metal wire having a third side length; the third side length being 0.73-0.77 times the second diameter. The wire material can be drawn into a nearly square shape for brazing connection to meet brazing requirements.

Description

Technical Field

[0001] The present application relates to the technical field of material preparation, and in particular to a square high-temperature aluminum brazing wire and a preparation method thereof. Background Art

[0002] Brazing is an ancient craft, a method for joining metals. It involves melting a filler metal with a lower melting point than the base metal to join the workpieces together, without melting the base metal itself. Examples include soldering with an electric iron, various copper and silver soldering methods. Despite its age, brazing remains a long-standing method. On the contrary, in recent decades, it has experienced significant development and widespread application based on modern technology. It plays a particularly important role in electromechanics, radio, instrumentation, and aerospace, becoming an irreplaceable process. The continuous emergence of new materials, with their diverse requirements for both the materials being joined and the brazing materials, has placed increasingly stringent demands on brazing technology, requiring continuous innovation in brazing connection processes.

[0003] Currently, high-temperature wire solder used in furnace welding and flame welding needs to be cut and placed at one end of the weld during the welding process. However, the round wire tends to roll after placement, which can lead to cold solder joints and leaks, posing a quality risk and causing significant signal attenuation in waveguide devices.

[0004] Therefore, a new high-temperature aluminum brazing wire is urgently needed. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a square high-temperature aluminum brazing wire and a preparation method thereof.

[0006] Based on the above objectives, the present application provides a method for preparing square high-temperature aluminum brazing wire, the preparation method comprising:

[0007] Providing a melted brazing filler metal, wherein the brazing filler metal comprises aluminum and silicon;

[0008] Performing silicon modification treatment on the brazing filler metal and refining the same to obtain modified brazing filler metal;

[0009] Casting the modified brazing filler metal to obtain an ingot;

[0010] performing a first hot extrusion process on the ingot multiple times to obtain a round wire solder of a first diameter;

[0011] performing a second hot extrusion process on a round wire solder having the first diameter for a plurality of times, and performing a first annealing process after each predetermined second extrusion process, to obtain a round wire solder having a second diameter; wherein the second diameter is 0.23-0.28 times the first diameter;

[0012] The round solder wire of the second diameter is cold drawn in a chamfered drawing die, and subjected to a second annealing treatment during the cold drawing process to obtain a square high-temperature aluminum solder wire with a third side length; the third side length is 0.73-0.77 times the second diameter.

[0013] In some embodiments, in the first hot extrusion process, the second hot extrusion process and the cold drawing process, the diameter change amount each time is 0.05 times the second diameter.

[0014] In some embodiments, cold drawing the round solder wire of the second diameter in a chamfered drawing die specifically includes:

[0015] Providing a plurality of molds, wherein the plurality of molds respectively have different straight side lengths and chamfer radii;

[0016] The round solder wire having the second diameter is sequentially cold-drawn in the plurality of dies.

[0017] In some embodiments, performing the second annealing treatment during the cold drawing process specifically includes: performing the second annealing treatment on each of the other cold drawing processes except the last two cold drawing processes.

[0018] In some embodiments, the preset number of times is two.

[0019] In some embodiments, the temperature of the first annealing treatment and the second annealing treatment are both 295-305° C., and the holding time is both 30 minutes.

[0020] In some embodiments, performing silicon modification treatment and refining on the brazing material comprises:

[0021] Add lanthanum modifier in batches at a mass fraction of 0.1-0.3% of the solder;

[0022] After the lanthanum modifier is melted, an aluminum-strontium master alloy and an aluminum-magnesium master alloy are added; the aluminum-strontium master alloy accounts for 0.05-0.1% of the solder by mass;

[0023] Add inert gas for refining.

[0024] In some embodiments, the temperature of the first hot extrusion process and the second hot extrusion process are both 495-505°C.

[0025] In some embodiments, the third side length is 1.5 mm.

[0026] The embodiment of the present application further provides a square high-temperature aluminum brazing wire, which is prepared using the preparation method of the square high-temperature aluminum brazing wire as described in any of the preceding items.

[0027] As can be seen from the above, the preparation method of the square high-temperature aluminum solder wire provided in the present application is as follows: providing a melted solder, wherein the solder includes aluminum and silicon; performing silicon modification treatment on the solder and refining to obtain a modified solder; casting the modified solder to obtain an ingot; performing a first hot extrusion treatment on the ingot multiple times to obtain a round wire solder of a first diameter; performing a second hot extrusion treatment on the round wire solder of the first diameter multiple times, and performing a first annealing treatment after each preset second extrusion treatment to obtain a round wire solder of a second diameter; the second diameter is 0.23-0.28 times the first diameter; cold drawing the round wire solder of the second diameter in a chamfered drawing die, and performing a second annealing treatment during the cold drawing process to obtain a square high-temperature aluminum solder wire having a third side length; the third side length is 0.73-0.77 times the second diameter, which can improve the plasticity of the casting material, avoid wire breakage during the drawing process, and finally draw it into a nearly square wire, which can be used for brazing connection to meet brazing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] Figure 1 Schematic diagram of the process of preparing the square high-temperature aluminum brazing wire according to the embodiment of the present application;

[0030] Figure 2 This is another schematic flow chart of the method for preparing square high-temperature aluminum brazing wire according to an embodiment of the present application;

[0031] Figure 3 Schematic diagram of the metallographic phase of the ingot after the second step of modification in Example 1;

[0032] Figure 4 This is a schematic diagram of the square high-temperature vacuum aluminum solder foil prepared in Example 1. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0034] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0035] Square wire, due to its resistance to rolling, can effectively avoid problems such as cold welds and leaks. However, current wires are typically round and can be produced using circular molds, which can be produced simply by gradually reducing the wire radius during the process. However, circular molds are not suitable for processing square wires. Furthermore, due to the relatively sharp corners of square wires, direct extrusion can easily cause wire breakage. Therefore, the extrusion and drawing methods currently used in wire production are suitable for round wires, but not for processing square wires.

[0036] Based on this, the embodiments of the present application provide a square high-temperature aluminum brazing wire and a preparation method thereof, which can solve the processing problem of square wire to a certain extent.

[0037] See also Figure 1 and Figure 2 The present invention provides a method for preparing a square high-temperature aluminum brazing wire, the method comprising:

[0038] S100, providing a melted brazing filler metal, wherein the brazing filler metal includes aluminum and silicon;

[0039] S200, performing silicon modification treatment on the solder and refining to obtain modified solder;

[0040] S300, casting the modified brazing filler metal to obtain an ingot;

[0041] S400, performing a first hot extrusion process on the ingot multiple times to obtain a round wire solder of a first diameter;

[0042] S500, subjecting the round solder wire of the first diameter to a plurality of second hot extrusion processes, and performing an annealing process after each predetermined number of second extrusion processes, to obtain a round solder wire of a second diameter; the second diameter being 0.23-0.28 times the first diameter;

[0043] S600: cold-drawing the round solder wire of the second diameter in a chamfered drawing die, and performing a second annealing treatment during the cold-drawing process to obtain a square high-temperature aluminum solder wire with a third side length; the third side length is 0.73-0.77 times the second diameter.

[0044] In some embodiments, in step S100, providing the melted solder may specifically include:

[0045] Melt the aluminum-silicon master alloy and pure aluminum. This can be done in a medium-frequency furnace or a resistance furnace. The specific amounts of aluminum-silicon master alloy and pure aluminum used are determined based on the composition requirements of the square high-temperature aluminum brazing wire to be prepared. A silicon content of 10.5-12.5% by mass in the brazing material provides good fluidity. At room temperature, this silicon content forms a single phase.

[0046] After the aluminum-silicon master alloy and pure aluminum ingot are melted, maintain the furnace temperature at 700-750℃.

[0047] In some embodiments, in step S200, silicon can be modified using lanthanum and aluminum-strontium alloys. The lanthanum modifier can comprise 0.1-0.3% by mass of the brazing filler metal, and the aluminum-strontium master alloy can comprise 0.05-0.1% by mass of the brazing filler metal. This allows for effective silicon modification, transforming the dendritic silicon into vermicular spheroids, significantly reducing the filler metal's brittleness and preventing wire breakage during subsequent rolling.

[0048] In some embodiments, adding a modifier to the melted solder for refining may specifically include:

[0049] Lanthanum modifiers are added in batches at a rate of 0.1-0.3% by mass to the brazing filler metal, with the furnace temperature controlled at 700-750°C. This stepwise addition enhances the silicon's modification, resulting in a more complete transformation of the aluminum-silicon master alloy and pure aluminum. This transforms the silicon in the alloy from dendritic to vermicular, preventing the gradual growth of silicon during the cooling process after casting, which can lead to low ingot plasticity. This improves the alloy's plasticity, further enhancing the brazing filler metal's profile processing properties while also ensuring mechanical properties such as weldability.

[0050] After the lanthanum modifier is melted, an aluminum-strontium master alloy and an aluminum-magnesium master alloy are added; the aluminum-strontium master alloy accounts for 0.05-0.1% of the solder by mass. The mass of the aluminum-strontium master alloy can be determined based on the composition requirements of the square high-temperature aluminum solder wire to be prepared. Specifically, after the lanthanum modifier is melted, the aluminum-strontium master alloy can be added at a ratio of 0.05-0.1%. The temperature is maintained at 700°C. After the aluminum-strontium master alloy is melted, the temperature is maintained at 700-750°C for 40 minutes. After the 40-minute temperature maintenance period, the aluminum-magnesium master alloy is added, and the furnace temperature is controlled at 700°C.

[0051] Add inert gas for refining. The inert gas can be argon, etc. The refining temperature can be 750°C and the refining time can be 20-30 minutes.

[0052] In some embodiments, in step S300 , the casting may be performed in a mold, for example, in an iron wire mold, wherein the size of the iron wire mold may be 600 mm×φ90 mm.

[0053] In some embodiments, in step S400, the temperature of the first hot extrusion process may be 495-505°C to prevent melting of the ingot while effectively deforming the ingot. A 600-ton hot extruder may be used for the extrusion process. During each first hot extrusion process, the diameter reduction may be 0.01 mm to minimize wire breakage.

[0054] In some embodiments, in step S500, the temperature of the second hot extrusion treatment can be 495-505°C, which can avoid the melting of the ingot and can well deform the ingot. The diameter change amount each time is 0.05 times the second diameter, for example, it can be 0.01mm each time, which can minimize wire breakage. The preset number of times is two times, that is, after every two second hot extrusion treatments, the first annealing treatment is performed after each 0.2mm diameter change. In this way, hardening can be eliminated and hardening phenomena can be avoided during the drawing process. By drawing the round wire solder into a round wire solder of the second diameter and then changing the mold for drawing, the occurrence of wire breakage can be reduced and it can be ensured that the wire is drawn to a nearly square shape after multiple chamfered drawing.

[0055] The first annealing treatment can be performed at a temperature of 295-305°C for 30 minutes. Setting the temperature at 295-305°C allows the alloy to achieve good thermoplasticity, reduces the metal's resistance to plastic deformation, achieves uniform temperature distribution throughout the alloy, and refines silicon, significantly improving the filler metal's plasticity. This allows the hot-rolled round wire filler metal to undergo further rolling processes, such as cold drawing.

[0056] In some embodiments, in step S600, the diameter change amount each time is 0.05 times the second diameter, for example, 0.01 mm each time, which can minimize wire breakage.

[0057] In some embodiments, cold drawing the round solder wire of the second diameter in a chamfered drawing die specifically includes:

[0058] A plurality of molds are provided, each having different straight side lengths and chamfer radii. The size of the right-angled side of the mold can be gradually increased to the size of the third side length, and the chamfer radius can be gradually reduced to zero.

[0059] The round wire solder having the second diameter is sequentially cold-drawn in the plurality of dies. The annealing treatment during the cold-drawing process may be a second annealing process performed on each of the cold-drawing processes except for the last two cold-drawing processes. The specific content of the second annealing process may be the same as the first annealing process and will not be further described herein.

[0060] In some embodiments, performing the second annealing treatment during the cold drawing process specifically includes performing the second annealing treatment on each of the cold drawing processes except for the last two cold drawing processes. This can ensure that the square high-temperature aluminum brazing filler metal is hardened, ultimately obtaining a third square high-temperature aluminum brazing filler metal wire with a side length of 1.5 mm.

[0061] Based on the same inventive concept, an embodiment of the present invention further provides a square high-temperature aluminum brazing wire, which is prepared by the processing method of the square high-temperature aluminum brazing wire described in any one of the above technical solutions.

[0062] The technical solution of the present invention is further described below with reference to specific implementation methods.

[0063] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0064] Unless otherwise specified, the test materials used in the following examples were purchased from conventional biochemical reagent stores.

[0065] Example A square high-temperature vacuum aluminum brazing foil with a side length of 1.5 mm was prepared, and the composition was Si: 11.78%, Fe: 0.03%, La: 0.10% and Sr: 0.002%.

[0066] Step 1: Solder melting:

[0067] Use a medium frequency furnace or resistance furnace to melt 100kg of aluminum-silicon master alloy and 50kg of pure aluminum according to the calculated brazing material ratio. After the aluminum-silicon master alloy and pure aluminum ingot are melted, maintain the furnace temperature at 700-750℃.

[0068] Step 2: Silicon deterioration treatment:

[0069] A modifier is slowly added in batches at a ratio of 0.2% of lanthanum and a ratio of 0.3kg, and the furnace temperature is controlled at 700-750°C. After the lanthanum modifier is melted, 1.125kg of an aluminum-strontium master alloy is added at a ratio of 0.75%, and the temperature is maintained at 700°C. After the aluminum-strontium master alloy is melted, the temperature is kept at 40 minutes, and the furnace temperature is controlled at 700-750°C. After the temperature is kept, the charge is refined using argon inert gas at a refining temperature of 750°C and a refining time of 20-30 minutes.

[0070] Step 3: Ingot casting:

[0071] After refining, casting is performed; the wire mold is: 600mm×φ90mm.

[0072] Step 4: Round wire extrusion molding:

[0073] The extruder uses a 600-ton hot extruder, and the hot extrusion temperature is controlled at 500±5℃. Multiple hot extrusions are performed, and the diameter change each time is 0.1mm. The ingot is hot extruded into a round wire solder of about 8mm (ie the first diameter).

[0074] Step 5: Round wire drawing:

[0075] The extruder uses a 600-ton hot extruder, with the extrusion temperature controlled at 500 ± 5°C. Multiple hot extrusions are performed, each with a diameter change of 0.1 mm. Annealing is performed every 0.2 mm. The annealing temperature is 300°C, and the holding time is 30 minutes. The result is a 2 mm (second diameter) round wire solder.

[0076] Step 6: Square wire forming:

[0077] The diameter reduction is controlled at 0.1mm per stroke, and the process is performed in a chamfering die. The straight edge of the chamfering die is designed to have angles of 0.4, 0.6, 0.8, 1.2, and 1.5mm, with chamfer radii of 0.75, 0.6, 0.45, 0.15, and 0.0mm, respectively. The final two drawing passes are not annealed, resulting in a square wire of high-temperature aluminum brazing filler metal with a side length of 1.5mm (the third side).

[0078] Example 2

[0079] The only difference from Example 1 is that in the fifth step, a round wire solder with a diameter of 1.8 mm (ie, the second diameter) is obtained.

[0080] Example 3

[0081] The only difference from Example 1 is that in the fifth step, a round wire solder with a diameter of 2.2 mm (ie, the second diameter) is obtained.

[0082] Comparative Example 1

[0083] The only difference from Example 1 is that the first diameter in the fourth step is 2 mm, and the fifth step is not included.

[0084] Comparative Example 2

[0085] The only difference from Example 1 is that in the fifth step, annealing is performed every time the diameter changes by 0.4 mm.

[0086] Comparative Example 3

[0087] The only difference from Example 1 is that the diameter of the round wire solder obtained in the fifth step is 3 mm (ie the second diameter is 3 mm).

[0088] Comparative Example 4

[0089] The only difference from Example 1 is that the diameter of the round wire solder obtained in the fifth step is 1 mm (ie the second diameter is 1 mm).

[0090] Test Case

[0091] The square high-temperature aluminum brazing wires of Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The tensile strength was tested using the GB / T 2651-2008 welded joint tensile test method, and the bending angle was tested using the GB / T 2653-2008 welded joint bending test method. The test results are shown in Table 1. In addition, the metallographic microscopy method was used to observe the metallographic phase of the ingot after the second step of the modification treatment in Example 1. The results are shown in Table 1. Figure 3 The square high temperature aluminum brazing wire finally prepared in Example 1 is as follows Figure 4 shown.

[0092] Table 1 Properties of square high temperature aluminum brazing wire

[0093]

[0094] It can be seen that the square high-temperature vacuum aluminum solder foils prepared in Examples 1 to 3 of the present application have good tensile strength and good bending angles, and can be used for welding waveguide devices, etc.

[0095] Comparing each embodiment with Comparative Example 1, it can be seen that when the round wire solder is directly hot-extruded without annealing and the cold drawing process is carried out in the chamfering die, wire breakage will occur, and it is impossible to prepare a square high-temperature vacuum aluminum solder foil. Comparing each embodiment with Comparative Example 2, it can be seen that when the diameter change is greater than 0.2mm, annealing is carried out, and the cold drawing process is carried out in the chamfering die, wire breakage will occur, and it is impossible to prepare a square high-temperature vacuum aluminum solder foil. Comparing each embodiment with Comparative Example 3, when the diameter of the round wire solder is greater than the set range of this application, cold drawing is carried out in the chamfering die, wire breakage will occur, and it is impossible to prepare a square high-temperature vacuum aluminum solder foil. Comparing each embodiment with Comparative Example 4, it can be seen that when the diameter of the round wire solder is less than the set range of this application, cold drawing is carried out in the chamfering die, wire breakage will occur, and it is impossible to prepare a square high-temperature vacuum aluminum solder foil.

[0096] Therefore, in the present application, the amount of each drawing is 0.1mm when processing square wire. Before drawing to the final size, a round wire die is first used for drawing. When drawing to 8mm, annealing treatment is performed after each diameter change of 0.2mm. Then, after pulling to 1.8mm-2.0mm, a square die with chamfered corners is used for drawing. The chamfer of the square die gradually decreases, which can improve the plasticity of the casting material and avoid wire breakage. Finally, the wire is drawn into a nearly square shape, which can be used for brazing connection and meet brazing requirements.

[0097] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples. Within the scope of the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present disclosure as described above, which are not provided in detail for the sake of simplicity.

[0098] While the disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0099] The embodiments of the present disclosure are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A method for preparing square high-temperature aluminum brazing wire, characterized in that: The preparation method comprises: Providing a melted brazing filler metal, wherein the brazing filler metal comprises aluminum and silicon; Performing silicon modification treatment on the brazing filler metal and refining the same to obtain modified brazing filler metal; Casting the modified brazing filler metal to obtain an ingot; performing a first hot extrusion process on the ingot multiple times to obtain a round wire solder of a first diameter; performing a second hot extrusion process on a round wire solder having the first diameter for a plurality of times, and performing a first annealing process after each predetermined second extrusion process, to obtain a round wire solder having a second diameter; wherein the second diameter is 0.23-0.28 times the first diameter; cold-drawing the round solder wire of the second diameter in a chamfered drawing die, and performing a second annealing process during the cold-drawing process to obtain a square high-temperature aluminum solder wire having a third side length; the third side length is 0.73-0.77 times the second diameter; In the first hot extrusion process, the second hot extrusion process and the cold drawing process, the diameter change amount each time is 0.05 times the second diameter; The cold drawing process of the round solder wire of the second diameter in a drawing die with chamfers specifically includes: Providing a plurality of molds, wherein the plurality of molds respectively have different straight side lengths and chamfer radii; The round solder wire having the second diameter is sequentially cold-drawn in the plurality of dies.

2. The method for preparing square high-temperature aluminum brazing wire according to claim 1, characterized in that: The second annealing treatment during the cold drawing process specifically includes: The second annealing treatment is performed on each of the cold drawing treatments except the last two cold drawing treatments.

3. The method for preparing square high-temperature aluminum brazing wire according to claim 1, characterized in that: The preset number of times is two times.

4. The method for preparing square high-temperature aluminum brazing wire according to claim 1, characterized in that: The temperature of the first annealing treatment and the second annealing treatment are both 295-305° C., and the holding time is both 30 minutes.

5. The method for preparing square high-temperature aluminum brazing wire according to claim 1, characterized in that: The solder is subjected to silicon modification and refining, comprising: Add lanthanum modifier in batches at a mass fraction of 0.1-0.3% of the solder; After the lanthanum modifier is melted, an aluminum-strontium master alloy and an aluminum-magnesium master alloy are added; the aluminum-strontium master alloy accounts for 0.05-0.1% of the solder by mass; Add inert gas for refining.

6. The method for preparing square high-temperature aluminum brazing wire according to claim 1, characterized in that: The temperatures of the first hot extrusion process and the second hot extrusion process are both 495-505°C.

7. The method for preparing square high-temperature aluminum brazing wire according to claim 1, characterized in that: The third side length is 1.5 mm.

8. A square high-temperature aluminum brazing wire, characterized in that: The square high-temperature aluminum brazing wire is prepared by the preparation method of any one of claims 1 to 7.

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