Brazing filler metal alloy powder, composite brazing filler metal and preparation method and application of composite brazing filler metal

Abstract

The invention discloses brazing filler metal alloy powder. The brazing filler metal alloy powder comprises 92-95 omega t% of cadmium; 1.5 [omega] t% to 6 [omega] t% of zinc; 2 [omega] t% to 3.5 [omega] t% of silver; and 0.8 to 1.2 omega t% of silicon. The brazing filler metal alloy powder has good wettability on the surfaces of damping alloy and stainless steel, the melting temperature is low, brazing of a damping alloy pipeline and a stainless steel pipeline at the low temperature can be achieved, and the heat influence of the welding temperature on the damping alloy is reduced; compared with the conventional bonding of damping alloy and stainless steel, a brazed joint prepared from the brazing filler metal has better mechanical properties and higher service temperature, and the application scene of a damping alloy-stainless steel pipeline is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of brazing materials, and in particular relates to a brazing alloy powder, a composite brazing material for brazing a damping alloy vibration-reducing component, a preparation method and application thereof, and a brazing method. Background Art

[0002] MnCu damping alloy is a vibration-reducing material that can quickly convert vibration energy into heat energy. It has excellent strength and plasticity and is often used in the manufacture of vibration-reducing and noise-reducing components in the fields of nuclear power engineering, rail transit, and ships. However, components designed and manufactured solely based on damping alloys are no longer able to meet the needs of actual working conditions. Stainless steel has high heat resistance, corrosion resistance, and a small thermal expansion coefficient. Connecting the two can complement each other's advantages and obtain structural components with good comprehensive performance.

[0003] Due to the difference in performance between MnCu damping alloy and stainless steel, ordinary fusion welding is prone to defects such as overburning and cracks caused by welding stress at the joint. In addition, damping and vibration reduction components have strict requirements on welding temperature when used in certain fields. Brazing is an ideal method for connecting dissimilar materials. It can achieve the connection of dissimilar materials under lower temperature conditions and reduce the generation of joint stress. Using brazing to connect MnCu damping alloy and stainless steel can obtain a joint with good performance while maintaining the performance of the parent material.

[0004] Pipeline structure is a commonly used structure in the manufacturing process of damping and vibration reduction components. Usually, the brazing of pipes is mostly done by filler wire. When the pipe size is large or the difference in diameter between the inner and outer pipes is small, the use of filler wire brazing will make it difficult to fill the gap with brazing material, reduce the brazing rate, and reduce the performance of the joint.

[0005] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed before the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0006] In view of this, in order to overcome the defects of the prior art, one of the objects of the present invention is to provide a solder alloy powder that can be formed into a composite solder blank by laser 3D printing.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A solder alloy powder comprises 92ωt% to 95ωt% of cadmium, 1.5ωt% to 6ωt% of zinc, 2ωt% to 3.5ωt% of silver, and 0.8ωt% to 1.2ωt% of silicon. Compared with conventional solders, the solder has a melting range of 300 to 320°C, is suitable for medium-temperature brazing of damping alloys, has good wettability on both damping alloys and stainless steel, and the prepared damping alloy-stainless steel joint has good performance.

[0009] According to some preferred embodiments of the present invention, the purity of cadmium is ≥99.99%; the purity of zinc is ≥99.995%; the purity of silver is ≥99.9%; the purity of silicon is ≥99.99%, thus ensuring the purity of the prepared solder.

[0010] According to some preferred embodiments of the present invention, the particle size of the solder alloy powder is 25-45 μm, so as to be suitable for powder feeding to a 3D printing device.

[0011] The second object of the present invention is to provide a method for preparing the solder alloy powder as described above, comprising the following steps: mixing cadmium powder, zinc powder, silver powder and silicon powder uniformly and grinding them, and screening out powder of 25 to 45 microns. Grinding is performed by a ball mill, and the speed of the ball mill is 500 to 1000 r / min. The preparation method ensures that the raw material powders for preparing the solder are uniformly mixed, and the prepared solder composition is relatively uniform.

[0012] The third object of the present invention is to provide a composite brazing material, which comprises a first brazing material layer, a brazing material layer and a second brazing material layer in sequence, wherein the brazing material layer is prepared from the brazing material alloy powder as described above. The function of the brazing material layer is to remove the oxide film on the surface of the damping alloy and the stainless steel during brazing.

[0013] According to some preferred embodiments of the present invention, the first flux layer and / or the second flux layer is obtained by drying a flux mixture coated on the solder layer, wherein the flux mixture comprises a flux and a binder, and the weight ratio of the flux to the binder is 3.5-4.5:1, preferably 4:1.

[0014] According to some preferred embodiments of the present invention, the flux is one or more selected from zinc chloride, ammonium chloride, cadmium chloride, potassium chloride, sodium chloride, and sodium fluoride. Preferably, the flux of the first flux layer and / or the second flux layer is selected from multiple types of zinc chloride, ammonium chloride, cadmium chloride, potassium chloride, sodium chloride, and sodium fluoride, and is prepared using a binder, and the first flux layer and / or the second flux layer are obtained after drying. Preferably, the first flux layer and the second flux layer have the same composition.

[0015] According to some preferred implementation aspects of the present invention, the binder is a mixture of polyvinyl alcohol or pineol and anhydrous ethanol, and the weight ratio of polyvinyl alcohol or pineol to anhydrous ethanol is 1.8-2.2:1, preferably 2:1.

[0016] A fourth object of the present invention is to provide a method for preparing the composite solder as described above, comprising the following steps:

[0017] The solder alloy powder as described above is printed by laser 3D printing to obtain a solder layer;

[0018] The two sides of the solder layer are covered with a flux mixture respectively. After drying, the flux mixture forms a first solder layer and / or a second solder layer, and the composite solder is obtained.

[0019] According to some preferred embodiments of the present invention, when laser 3D printing is performed, the size of the brazing material layer to be printed needs to be designed and modeled using 3D design software. Preferably, the brazing material layer of the brazing material alloy powder laser 3D printing is cylindrical so that it can be assembled between the damping alloy (pipeline) and the stainless steel pipe.

[0020] According to some preferred implementation aspects of the present invention, the laser power of the laser 3D printing is 200-350 W, the scanning speed is 1200-1800 mm / s, and the printing is performed under argon protection.

[0021] According to some preferred embodiments of the present invention, the drying is performed at 100-150°C.

[0022] In some embodiments of the present invention, the preparation method of the composite solder specifically comprises the following steps:

[0023] Step 1: Prepare the ingredients

[0024] Cadmium, zinc, silver and silicon are prepared according to the composition of the solder alloy powder, wherein the purity of the elemental powder is Cd (≥99.99%), Ag (≥99.9%), Zn (≥99.995%), Si (≥99.99%), and the weight percentages are Cd 92ωt%~95ωt%; Zn 1.5ωt%~6ωt%; Ag 2ωt%~3.5ωt%; Si 0.8ωt%~1.2ωt%.

[0025] Step 2: Preparation of solder alloy powder

[0026] The weighed cadmium, zinc, silver and silicon are mixed evenly in a powder mixer, and then the mixed powder is ball-milled using a ball mill. Finally, powders of 25 to 45 microns are screened out as solder alloy powders for 3D printing raw materials, wherein the rotation speed of the ball mill is 500 to 1000 r / min.

[0027] Step 3: Laser 3D printing

[0028] Design the specific specifications and dimensions of the solder alloy (solder layer blank) to be printed, use 3D design software (such as Solidworks, UG, etc.) to model, set the laser power to 200-350W, the scanning speed to 1200-1800mm / s, and perform laser 3D printing under argon protection to form the solder layer blank.

[0029] The brazing alloy powder is preferably laser 3D printed into a cylindrical brazing layer so that it can be assembled between the damping alloy (pipe) and the stainless steel pipe.

[0030] Step 4:

[0031] Prepare the flux mixture and use a soft brush to evenly apply it to the inside and outside of the 3D printed solder layer to form the first flux layer and the second flux layer.

[0032] Step 5: Drying

[0033] Place in an oven at 100-150℃ and dry for 1.5-3h.

[0034] A fifth object of the present invention is to provide an application of the composite solder as described above in brazing pipeline damping and vibration reduction components.

[0035] A sixth object of the present invention is to provide a method for applying the composite solder as described above to brazing of pipeline damping and vibration reduction components, comprising the following steps:

[0036] Treat the surface of the substrate to be brazed;

[0037] Assemble the pipeline, composite brazing material and damping alloy pipeline in sequence;

[0038] Raise the temperature of the area to be brazed to between 350 and 360°C for brazing;

[0039] Keep warm for 10 to 15 minutes and then air cool to room temperature.

[0040] In some embodiments of the present invention, a method for applying a composite brazing material to brazing a pipeline damping and vibration reduction component comprises the following steps:

[0041] Step 1: Preprocessing

[0042] The stainless steel pipe and the damping alloy substrate to be brazed are sandblasted to remove surface dirt and rust, and are ultrasonically cleaned in anhydrous ethanol and then dried for use.

[0043] Step 2: Assembly

[0044] Assemble the treated stainless steel pipes, composite brazing filler metals and damping alloy pipes in sequence.

[0045] Step 3: Brazing

[0046] Use a flexible heating blanket to cover the area to be welded, and adjust the heating temperature to 350-360℃ for brazing. Use a flexible heating blanket to heat the brazing method and accurately control the brazing temperature.

[0047] Step 4: Cooling

[0048] After reaching the predetermined temperature, keep it warm for 10 to 15 minutes, then air cool to room temperature to complete brazing.

[0049] Due to the adoption of the above technical scheme, compared with the prior art, the advantages of the present invention are: the solder alloy powder of the present invention has good wettability on the surfaces of the damping alloy and stainless steel, and has a low melting temperature, so that the damping alloy pipeline and the stainless steel pipeline can be brazed at a lower temperature, reducing the thermal effect of the welding temperature on the damping alloy; compared with the current adhesive bonding of the damping alloy and stainless steel, the brazed joint prepared using the solder alloy has better mechanical properties and higher service temperature, which expands the application scenarios of the damping alloy-stainless steel pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0051] Figure 1 A schematic diagram of the structure of the composite solder in a preferred embodiment of the present invention;

[0052] Figure 2 This is a SEM image of the solder structure after laser 3D printing observed under an electron microscope in a preferred embodiment of the present invention;

[0053] Figure 3 This is a schematic diagram of the brazing structure assembly in a preferred embodiment of the present invention;

[0054] In the accompanying drawings, the reference numerals are: first brazing flux layer-1, brazing filler metal layer-2, second brazing flux layer-3, damping alloy-4, composite brazing filler metal-5, stainless steel pipe-6. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. 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 creative work should fall within the scope of protection of the present invention.

[0056] The present invention provides a brazing alloy powder for brazing damping alloy materials and suitable for laser 3D printing, and a preparation method thereof, including a composite brazing material 5 of a brazing layer 2 formed by the brazing alloy powder, a preparation method of the composite brazing material 5, and application of the composite brazing material 5 in brazing damping and vibration reduction components.

[0057] The solder alloy powder of the present invention has a particle size of 25 to 45 μm, and comprises 92 ωt% to 95 ωt% of cadmium, 1.5 ωt% to 6 ωt% of zinc, 2 ωt% to 3.5 ωt% of silver, and 0.8 ωt% to 1.2 ωt% of silicon. The purity of the cadmium is ≥99.99%, the purity of the zinc is ≥99.995%, the purity of the silver is ≥99.9%, and the purity of the silicon is ≥99.99%.

[0058] The preparation method of the solder alloy powder of the present invention comprises the following steps: mixing cadmium powder, zinc powder, silver powder and silicon powder uniformly, grinding and screening out powder of 25 to 45 microns, and grinding by a ball mill at a rotation speed of 500 to 1000 r / min.

[0059] The cross-sectional structure diagram of the composite brazing material 5 for the damping alloy 4 provided by the present invention is as follows: Figure 1 The composite solder 5 is a sleeve-shaped structure, and the 3D printing modeling can be changed according to the different pipe diameters and diameter differences, so as to adapt. The composite solder 5 can solve the problem of difficult processing of foil solder, improve the problem of difficult filling of filament solder, reduce the defects caused by brazing, and improve the brazing rate of the joint surface of the brazing structure.

[0060] The first brazing agent layer and / or the second brazing agent layer are obtained by drying a brazing agent mixture, wherein the brazing agent mixture comprises a brazing agent and a binder, and the weight ratio of the brazing agent to the binder is 3.5-4.5:1, preferably 4:1. The brazing agent is one or more selected from zinc chloride, ammonium chloride, cadmium chloride, potassium chloride, sodium chloride, and sodium fluoride. Preferably, the brazing agent of the first brazing agent layer and / or the second brazing agent layer is selected from a plurality of zinc chloride, ammonium chloride, cadmium chloride, potassium chloride, sodium chloride, and sodium fluoride, and is prepared using a binder, and the first brazing agent layer and / or the second brazing agent layer are obtained after drying. Preferably, the first brazing agent layer and the second brazing agent layer have the same composition.

[0061] The binder is a mixture of polyvinyl alcohol or pine alcohol and anhydrous ethanol, and the weight ratio of polyvinyl alcohol or pine alcohol to anhydrous ethanol is 1.8-2.2:1, preferably 2:1.

[0062] The preparation method of the composite solder 5 of the present invention specifically comprises the following steps:

[0063] Step 1: Prepare the ingredients

[0064] Cadmium, zinc, silver and silicon are prepared according to the composition of the solder alloy powder, wherein the purity of the elemental powder is Cd (≥99.99%), Ag (≥99.9%), Zn (≥99.995%), Si (≥99.99%), and the weight percentages are Cd 92ωt%~95ωt%; Zn 1.5ωt%~6ωt%; Ag 2ωt%~3.5ωt%; Si 0.8ωt%~1.2ωt%.

[0065] Step 2: Preparation of solder alloy powder

[0066] The weighed cadmium, zinc, silver and silicon are mixed evenly in a powder mixer, and then the mixed powder is ball-milled using a ball mill. Finally, powders of 25 to 45 microns are screened out as solder alloy powders for 3D printing raw materials, wherein the rotation speed of the ball mill is 500 to 1000 r / min.

[0067] Step 3: Laser 3D printing

[0068] The specific specifications and dimensions of the solder alloy (solder layer 2 blank) to be printed are designed, modeled using 3D design software, the laser power is set to 200-350W, the scanning speed is 1200-1800mm / s, and laser 3D printing is performed under argon protection to form the solder layer 2 blank. The solder layer 2 blank is cylindrical.

[0069] Step 4:

[0070] Prepare a flux mixture and use a soft brush to evenly apply it to the inner and outer surfaces of the 3D printed solder layer 2 to form a first flux layer 1 and a second flux layer 3.

[0071] The flux mixture includes a flux and a binder, and the weight ratio of the flux to the binder is 3.5-4.5:1, preferably 4:1. The flux is one or more selected from zinc chloride, ammonium chloride, cadmium chloride, potassium chloride, sodium chloride, and sodium fluoride. The binder is a mixture of polyvinyl alcohol or pine alcohol and anhydrous ethanol, and the weight ratio of the polyvinyl alcohol or pine alcohol to the anhydrous ethanol is 1.8-2.2:1, preferably 2:1.

[0072] Step 5: Drying

[0073] Place in an oven at 100-150℃ and dry for 1.5-3h.

[0074] The product of the present invention has good wettability on both damping alloy 4 and stainless steel, and can form a brazed joint with good performance. The brazing material provided by the present invention is 3D printed into a sleeve shape, which can effectively reduce the difficulty of brazing material forming of a pipe-shaped workpiece and improve the efficiency of brazing assembly. The brazing method provided by the present invention is suitable for brazing of pipe-mounted workpieces, and has the advantages of accurate temperature control and precise time control.

[0075] The method for applying the composite brazing material 5 of the present invention to the brazing of pipeline damping and vibration reduction components comprises the following steps:

[0076] Step 1: Preprocessing

[0077] The stainless steel pipe 6 substrate to be brazed is sandblasted to remove surface dirt and rust, ultrasonically cleaned in anhydrous ethanol, and then dried for use.

[0078] Step 2: Assembly

[0079] The processed stainless steel pipe 6, composite solder 5 and damping alloy 4 pipe are assembled in sequence.

[0080] Step 3: Brazing

[0081] Use a flexible heating blanket to cover the area to be welded and adjust the heating temperature to 350-360℃ for brazing.

[0082] Step 4: Cooling

[0083] After reaching the predetermined temperature, keep it warm for 10 to 15 minutes, then air cool to room temperature to complete brazing.

[0084] Example 1

[0085] The alloy powder of the medium-temperature solder for the damping and vibration reduction component in this embodiment comprises the following components: cadmium, zinc, silver and silicon, and the weight percentages thereof are: 94.2% cadmium, 1.5% zinc, 3.5% silver and 0.8% silicon.

[0086] The composite solder 5 of this embodiment is cylindrical, and includes a first solder layer 1, a solder layer 2, and a second solder layer 3 from the outside to the inside, and the solder layer 2 is prepared from the solder alloy powder as described above. The preparation method of the composite solder 5 of this embodiment and the method of brazing a damping and vibration reduction component using the prepared composite solder 5 specifically include the following steps:

[0087] (1) Material preparation. Cadmium, zinc, silver and silicon are prepared according to the alloy powder composition, wherein the purity of the elemental powder is Cd (99.99%), Ag (99.9%), Zn (99.995%), Si (99.99%), and the weight percentage is 94.2% of cadmium, 1.5% of zinc, 3.5% of silver, and 0.8% of silicon;

[0088] (2) The weighed cadmium, zinc, silver and silicon are mixed evenly in a powder mixer, and then the mixed powder is ball-milled using a ball mill, and finally a powder of 25 to 45 microns is screened out as a solder alloy powder for 3D printing raw materials, wherein the rotation speed of the ball mill is 750 r / min;

[0089] (3) The dimensions of the composite solder 5 sleeve are designed to be 110 mm in inner diameter and 110.2 mm in outer diameter, and the laser power is set to 200 W and the scanning speed is set to 1200 mm / s for laser printing;

[0090] (4) Prepare the flux mixture, apply it evenly to the inside and outside of the 3D printed solder using a soft brush, and dry it in an oven at 120° C. for two hours to obtain a composite solder 5;

[0091] (5) The stainless steel pipe 6 substrate to be brazed is sandblasted to remove surface dirt and rust, ultrasonically cleaned in anhydrous ethanol, and then dried for later use;

[0092] (6) Assemble the stainless steel pipe 6, composite brazing material 5 and damping alloy 4 pipe in sequence. The assembly structure diagram is shown in the attached figure. Figure 3 As shown;

[0093] (7) Use a flexible heating blanket to cover the workpiece to be welded and adjust the heating temperature to 350°C for brazing;

[0094] (8) After reaching the predetermined temperature, keep it warm for 15 minutes and then air cool it to room temperature to complete the brazing.

[0095] Example 2

[0096] The alloy powder of the medium-temperature solder for the damping and vibration reduction component in this embodiment comprises the following components: cadmium, zinc, silver and silicon, and their weight percentages are: cadmium 94.0%, zinc 1.5%, silver 3.5% and silicon 1.0%.

[0097] The composite solder 5 of this embodiment is cylindrical, and includes a first solder layer 1, a solder layer 2, and a second solder layer 3 from the outside to the inside, and the solder layer 2 is prepared from the solder alloy powder as described above. The preparation method of the composite solder 5 of this embodiment and the method of brazing a damping and vibration reduction component using the prepared composite solder 5 specifically include the following steps:

[0098] (1) Material preparation. Prepare cadmium, zinc, silver and silicon according to the alloy powder composition, wherein the purity of the elemental powder is Cd (99.99%), Ag (99.9%), Zn (99.995%), Si (99.99%), and the weight percentage is 94.0% cadmium, 1.5% zinc, 3.5% silver, and 1.0% silicon;

[0099] (2) The weighed cadmium, zinc, silver and silicon are mixed evenly in a powder mixer, and then the mixed powder is ball-milled using a ball mill, and finally a powder of 25 to 45 microns is screened out as a solder alloy powder as a raw material for 3D printing, wherein the rotation speed of the ball mill is 900 r / min;

[0100] (3) The size of the solder sleeve is designed to be 110 mm in inner diameter and 110.2 mm in outer diameter. The laser power is set to 250 W and the scanning speed is set to 1500 mm / s for laser printing.

[0101] (4) Prepare the flux mixture, apply it evenly to the inside and outside of the 3D printed solder using a soft brush, and dry it in an oven at 120° C. for two hours to obtain a composite solder 5;

[0102] (5) The stainless steel pipe 6 substrate to be brazed is sandblasted to remove surface dirt and rust, ultrasonically cleaned in anhydrous ethanol, and then dried for later use;

[0103] (6) Assemble the stainless steel pipe 6, composite brazing material 5 and damping alloy 4 pipe in sequence. The assembly structure diagram is shown in the attached figure. Figure 3 As shown;

[0104] (7) Use a flexible heating blanket to cover the workpiece to be welded and adjust the heating temperature to 350°C for brazing;

[0105] (8) After reaching the predetermined temperature, keep it warm for 15 minutes and then air cool it to room temperature to complete the brazing.

[0106] Example 3

[0107] The alloy powder of the medium-temperature solder for the damping and vibration reduction component in this embodiment comprises the following components: cadmium, zinc, silver and silicon, and the weight percentages thereof are: cadmium 93.8%, zinc 1.5%, silver 3.5% and silicon 1.2%.

[0108] The composite solder 5 of this embodiment is cylindrical, and includes a first solder layer 1, a solder layer 2, and a second solder layer 3 from the outside to the inside, and the solder layer 2 is prepared from the solder alloy powder as described above. The preparation method of the composite solder 5 of this embodiment and the method of brazing a damping and vibration reduction component using the prepared composite solder 5 specifically include the following steps:

[0109] (1) Material preparation. Prepare cadmium, zinc, silver and silicon according to the alloy powder composition, wherein the purity of the elemental powder is Cd (99.99%), Ag (99.9%), Zn (99.995%), Si (99.99%), and the weight percentage is 93.8% cadmium, 1.5% zinc, 3.5% silver, and 1.2% silicon;

[0110] (2) The weighed cadmium, zinc, silver and silicon are mixed evenly in a powder mixer, and then the mixed powder is ball-milled using a ball mill, and finally a powder of 25 to 45 microns is screened out as a solder alloy powder for 3D printing raw materials, wherein the rotation speed of the ball mill is 1000 r / min;

[0111] (3) The size of the solder sleeve is designed to be 110 mm in inner diameter and 110.2 mm in outer diameter. The laser power is set to 350 W and the scanning speed is set to 1800 mm / s for laser printing.

[0112] (4) Prepare the flux mixture, apply it evenly to the inside and outside of the 3D printed solder using a soft brush, and dry it in an oven at 120° C. for two hours to obtain a composite solder 5;

[0113] (5) The stainless steel pipe 6 substrate to be brazed is sandblasted to remove surface dirt and rust, ultrasonically cleaned in anhydrous ethanol, and then dried for later use;

[0114] (6) Assemble the stainless steel pipe 6, composite brazing material 5 and damping alloy 4 pipe in sequence. The assembly structure diagram is shown in the attached figure. Figure 3 As shown;

[0115] (7) Use a flexible heating blanket to cover the workpiece to be welded and adjust the heating temperature to 350°C for brazing;

[0116] (8) After reaching the predetermined temperature, keep it warm for 15 minutes and then air cool it to room temperature to complete the brazing.

[0117] Example 4

[0118] The alloy powder of the medium-temperature solder for the damping and vibration reduction component in this embodiment comprises the following components: cadmium, zinc, silver and silicon, and their weight percentages are: cadmium 94.0%, zinc 1.5%, silver 3.5% and silicon 1.0%.

[0119] The composite solder 5 of this embodiment is cylindrical, and includes a first solder layer 1, a solder layer 2, and a second solder layer 3 from the outside to the inside, and the solder layer 2 is prepared from the solder alloy powder as described above. The preparation method of the composite solder 5 of this embodiment and the method of brazing a damping and vibration reduction component using the prepared composite solder 5 specifically include the following steps:

[0120] (1) Material preparation. Prepare cadmium, zinc, silver and silicon according to the alloy powder composition, wherein the purity of the elemental powder is Cd (99.99%), Ag (99.9%), Zn (99.995%), Si (99.99%), and the weight percentage is 94.0% cadmium, 1.5% zinc, 3.5% silver, and 1.0% silicon;

[0121] (2) The weighed cadmium, zinc, silver and silicon are mixed evenly in a powder mixer, and then the mixed powder is ball-milled using a ball mill, and finally a powder of 25 to 45 microns is screened out as a solder alloy powder as a raw material for 3D printing, wherein the rotation speed of the ball mill is 900 r / min;

[0122] (3) The size of the solder sleeve is designed to be 110 mm in inner diameter and 110.2 mm in outer diameter. The laser power is set to 250 W and the scanning speed is set to 1500 mm / s for laser printing.

[0123] (4) Prepare the flux mixture, apply it evenly to the inside and outside of the 3D printed solder using a soft brush, and dry it in an oven at 120° C. for two hours to obtain a composite solder 5;

[0124] (5) The stainless steel pipe 6 substrate to be brazed is sandblasted to remove surface dirt and rust, ultrasonically cleaned in anhydrous ethanol, and then dried for later use;

[0125] (6) Assemble the stainless steel pipe 6, composite brazing material 5 and damping alloy 4 pipe in sequence. The assembly structure diagram is shown in the attached figure. Figure 3 As shown;

[0126] (7) Use a flexible heating blanket to cover the workpiece to be welded and adjust the heating temperature to 360°C for brazing;

[0127] (8) After reaching the predetermined temperature, keep it warm for 10 minutes and then air cool it to room temperature to complete the brazing.

[0128] Comparative Example 1

[0129] The medium-temperature solder for the damping and vibration reduction components of this comparative example, as well as its preparation method and brazing method, are basically the same as those of Example 1, except that the solder alloy powder comprises 95% cadmium, 1.5% zinc and 3.5% silver, i.e., the solder alloy powder does not contain silicon.

[0130] Performance Testing and Results

[0131] The brazed pipes obtained in Examples 1 to 4 and Comparative Example 1 were tested for shear strength and shear strength after thermal cycle test.

[0132] Shear performance test: The test is carried out with reference to the national welding standard GB / T 11363-2008 brazing joint strength test method.

[0133] Thermal cycle test: The workpiece is heated from room temperature to 288°C and then cooled to room temperature, and the cycle is repeated 60 times.

[0134] The test results are shown in Table 1:

[0135] Table 1 Performance test results of embodiments and comparative examples

[0136] Experimental Group Shear resistance / MPa Shear resistance after thermal cycling / MPa Example 1 48.85 46.89 Example 2 54.05 52.33 Example 3 51.09 48.13 Example 4 52.13 49.21 Comparative Example 1 46.59 41.96

[0137] It can be seen from Table 1 that, compared with Comparative Example 1, the shear resistance of Examples 1 to 4 of the present invention is greatly improved. After the thermal cycle test, the strength decrease of the brazed joint is also significantly better than that of the comparative example, indicating that the medium-temperature brazing filler metal prepared by the present invention can effectively improve the strength of the brazed joint and improve the heat cycle resistance of the workpiece, thereby extending the service life of the workpiece.

[0138] The present invention provides a medium-temperature solder for brazing damping alloy vibration-damping components, and a preparation and brazing method thereof, which mainly include the design of solder composition, the preparation and molding method of the composite solder, and the preferred brazing method, which can ensure the bonding strength between the damping alloy and the stainless steel, and play an important role in improving the quality of the joint. Specifically, the first purpose of the present invention is to provide a Si particle reinforced composite solder for brazing damping vibration-damping components, which can realize the brazing connection of large-sized (pipes with a diameter greater than 200 mm) damping alloy pipes and stainless steel pipes. The second purpose of the present invention is to provide a method for preparing a composite solder for brazing damping vibration-damping components. The molding method is based on 3D printing technology, which can effectively control the molding size of the solder and reduce the molding difficulty. The third purpose of the present invention is to provide a preferred brazing method for damping vibration-damping components, which can achieve uniform heating and precise temperature control.

[0139] The medium-temperature solder for brazing the damping alloy vibration-damping component provided by the present invention can achieve excellent wettability on both the damping alloy and the stainless steel material, thereby ensuring the bonding strength between the damping alloy and the stainless steel; the sleeve-shaped solder preparation method provided can solve the problem that foil-shaped solder is difficult to process, improve the problem that filament-shaped solder is difficult to fill gaps, reduce defects caused by brazing, and improve the brazing rate; the damping alloy pipe and stainless steel pipe brazing method adopted can ensure accurate temperature control and uniform heating, with little influence on the structure and performance of the parent material, thereby obtaining a good brazing joint.

[0140] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A solder alloy powder, characterized in that: Including cadmium 92ωt%~95ωt%; zinc 1.5ωt%~6ωt%; silver 2ωt%~3.5ωt%; silicon 0.8ωt%~1.2ωt%.

2. The solder alloy powder according to claim 1, characterized in that The purity of the cadmium is ≥99.99%; the purity of the zinc is ≥99.995%; the purity of the silver is ≥99.9%; and the purity of the silicon is ≥99.99%.

3. The solder alloy powder according to claim 1, characterized in that The particle size of the solder alloy powder is 25 to 45 μm.

4. A method for preparing a solder alloy powder according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: mixing cadmium powder, zinc powder, silver powder and silicon powder uniformly, grinding the mixture and screening out powder with a size of 25 to 45 microns.

5. A composite solder, characterized in that: The method comprises a first brazing agent layer, a brazing material layer and a second brazing agent layer in sequence, wherein the brazing material layer is prepared from the brazing material alloy powder according to any one of claims 1 to 3.

6. The composite solder according to claim 5, characterized in that: The first brazing agent layer and / or the second brazing agent layer are obtained by drying a brazing agent mixture coated on the brazing material layer. The brazing agent mixture comprises a brazing agent and a binder. The weight ratio of the brazing agent to the binder is 3.5-4.5:

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7. The composite solder according to claim 6, characterized in that: The flux is one or more selected from zinc chloride, ammonium chloride, cadmium chloride, potassium chloride, sodium chloride and sodium fluoride.

8. The composite solder according to claim 6, characterized in that: The binder is a mixture of polyvinyl alcohol or pine alcohol and anhydrous ethanol, and the weight ratio of polyvinyl alcohol or pine alcohol to anhydrous ethanol is 1.8-2.2:

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9. A method for preparing a composite solder according to any one of claims 5 to 8, characterized in that: The steps include: Using laser 3D printing to obtain a brazing material layer using brazing material alloy powder; The two sides of the solder layer are covered with a flux mixture respectively. After drying, the flux mixture forms a first solder layer and / or a second solder layer, and the composite solder is obtained.

10. The preparation method according to claim 9, characterized in that: When performing laser 3D printing, it is necessary to design the size of the solder layer to be printed and use 3D design software for modeling.

11. The preparation method according to claim 9, characterized in that: The laser power of the laser 3D printing is 200-350W, and the scanning speed is 1200-1800mm / s.

12. The preparation method according to claim 9, characterized in that: The drying is carried out at 100-150°C.

13. Use of the composite brazing material according to any one of claims 5 to 8 in brazing pipeline damping and vibration reduction components.

14. A method for brazing pipeline damping and vibration reduction components using the composite brazing material as claimed in any one of claims 5 to 8, characterized in that: The steps include: Treat the surface of the substrate to be brazed; Assemble the pipeline, composite brazing material and damping alloy pipeline in sequence; Raise the temperature of the area to be brazed to between 350 and 360°C for brazing; Keep warm for 10 to 15 minutes and then air cool to room temperature.

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