Self-lubricating filamentous nickel-based brazing filler metal and preparation method and application thereof

Abstract

The invention discloses a self-lubricating filamentous nickel-based brazing filler metal and a preparation method and application thereof.The preparation method of the filamentous nickel-based brazing filler metal comprises the steps that alloy raw materials are smelted according to chemical components of the nickel-based brazing filler metal, and alloy melt is obtained; the alloy melt is subjected to atomization powder making through a gas atomization water cooling process, and the filamentous nickel-based brazing filler metal is obtained; wherein the nickel-based brazing filler metal is prepared from the following chemical components in percentage by mass: 29 to 30 percent of Cr, 3.85 to 4.15 percent of Si, 5.85 to 6.15 percent of P, 0.1 to 0.15 percent of B, 0.1 to 0.2 percent of Ce and the balance of Ni. The filamentous nickel-based brazing filler metal in a rapid solidification state is prepared by optimizing the components of the nickel-based brazing filler metal and accurately controlling the smelting and atomization processes, the filamentous nickel-based brazing filler metal is in a filamentous morphology, the special morphology enables the brazing filler metal to have self-lubricating performance, and compared with traditional powdery nickel-based brazing filler metal, the filamentous nickel-based brazing filler metal has the beneficial effects that the components are more uniform, the hardness is higher, and the service life is prolonged. The nickel-based brazing filler metal has the advantages of better wetting and flowability and higher spreading diffusivity, and the problems that existing nickel-based brazing filler metal is difficult to distribute and form and the like are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of brazing, and particularly relates to a self-lubricating filamentous nickel-based brazing filler metal, a preparation method thereof, and an application thereof. Background Art

[0002] Nickel-based brazing filler metals are high-temperature brazing filler metal alloys with a complex phase structure formed by using a nickel solid solution as a matrix and adding appropriate amounts of alloying elements such as Cr, B, Si, W, P, C, etc. They can braze various high-temperature alloys such as stainless steel, iron-based, nickel-based, and cobalt-based alloys. Nickel-based brazing filler metals have the advantages of high temperature resistance, corrosion resistance, and high strength at high temperatures. The working temperature of the brazed joint can be as high as 1000°C, and it has high tensile strength, shear strength, good oxidation resistance, salt spray corrosion resistance, and electrical conductivity at high temperatures. Therefore, nickel-based brazing filler metals are widely used in industrial fields such as machinery, aviation, and aerospace.

[0003] Due to the presence of strengthening elements such as Cr, Si, B, and P in nickel-based brazing filler metals, the brazing filler metals are brittle and have very poor formability. Therefore, it is very difficult to manufacture them into filamentous, sheet-like, etc. forms, and they are often made into powder states by atomization methods. However, for the welding of special structure parts such as honeycomb and large-area parts, there are operation process problems such as difficult control of powder distribution and addition amount of the powder state brazing filler metal, which severely restricts the application range of the brazing filler metal. Currently, by selecting appropriate adhesives and adhesives, alloy brazing filler metal powders can be prepared into tape brazing filler metals and paste brazing filler metals to improve the brazing filler metal distribution effect. However, a large amount of binders in the tape brazing filler metals and paste brazing filler metals will burst due to volatilization during heating, affecting the wetting characteristics of the brazing filler metal; moreover, these volatiles will affect the vacuum degree during vacuum brazing, prolong the brazing heating time, reduce production efficiency, and more importantly, will cause pollution to the vacuum furnace and vacuum system. Therefore, the use of tape brazing filler metals and paste brazing filler metals will bring new problems.

[0004] In view of the above technical problems, if the nickel-based brazing filler metal can be directly processed into a filamentous form and its lubricity and fluidity can be improved, then it is not necessary to prepare the nickel-based brazing filler metal into tape brazing filler metals and paste brazing filler metals, or very small amounts of adhesives or adhesive bases can be added to make tape brazing filler metals and paste brazing filler metals, thereby reducing or even avoiding the use of binders, and of course overcoming the problems such as difficult distribution and forming of nickel-based brazing filler metals.

[0005] The disclosed patent CN119035871A discloses a Ni-Cr-P series nickel-based brazing filler metal, a preparation method thereof, and a brazing method. The preparation process is based on the Ni-Cr-P series nickel-based brazing filler metal, doped with an appropriate amount of Y element, effectively improving the fluidity of the brazing filler metal, filling the weld porosity during the brazing process, reducing the generation of brittle phosphide phases, and improving the mechanical properties of the welded joint. Although it improves the fluidity of the brazing filler metal to a certain extent, it is not sufficient to change the processing form of the nickel-based brazing filler metal, and of course, it cannot overcome the problems such as difficult distribution and forming of the existing nickel-based brazing filler metals.

[0006] Patent CN114641363A also discloses a low-melting-point nickel-manganese-silicon-based brazing filler metal for heat exchanger applications. The main improvement method is to micro-alloy the alloy by controlling the addition of copper and a small amount of boron elements to improve the alloy properties. Compared with the commonly used BNi-8 type nickel-based brazing filler, the melting point of the alloy is significantly reduced, enabling heat exchangers with thin metal sheets to be brazed at lower temperatures. However, the above nickel-based brazing filler only modifies the Ni-Cr-P-based nickel-based brazing filler by micro-alloying to improve the performance of the material in terms of fluidity or welding melting point, and it is also not sufficient to change the processing form of the nickel-based brazing filler. Summary of the Invention

[0007] Based on the above technical problems, the present invention provides a self-lubricating filamentous nickel-based brazing filler and its preparation method and application. By optimizing the composition of the nickel-based brazing filler and precisely controlling the melting and atomization processes, a filamentous nickel-based brazing filler in a rapidly solidified state is prepared. It has a filamentous morphology, and this special morphology makes the brazing filler have self-lubricity. Compared with traditional powdered nickel-based brazing fillers, it has the advantages of more uniform composition, better wetting and fluidity, and higher spreading and diffusivity, overcoming the problems such as difficult cloth laying and forming of existing nickel-based brazing fillers.

[0008] A preparation method of a self-lubricating filamentous nickel-based brazing filler proposed by the present invention includes the following steps:

[0009] S1. Melting alloy raw materials according to the chemical composition of the nickel-based brazing filler to obtain an alloy melt;

[0010] S2. Atomizing the alloy melt by a gas atomization water cooling process to obtain the filamentous nickel-based brazing filler;

[0011] Among them, the chemical composition of the nickel-based brazing filler by mass percentage includes: Cr: 29-30%, Si: 3.85-4.15%, P: 5.85-6.15%, B: 0.1-0.15%, Ce: 0.1-0.2%, and the balance is Ni.

[0012] In the present invention, based on the BNi5-X nickel-based filler metal, the composition is improved. For the national standard composition with the balance of Ni, Cr content of 28.0%-30.0%, Si content of 3.0%-5.0%, and P content of 5.0%-7.0%, the Cr content is controlled at 29%-30%, the Si content is controlled at 3.85%-4.15%, and the P content is controlled at 5.85%-6.15%. At the same time, B element is added by means of microalloying with a content of 0.1%-0.15%, and Ce element is added with a content of 0.1%-0.2%. The B element and the Ce element cooperate to control the melting point of the nickel-based filler metal, making the temperature range required for the solidification process of the nickel-based filler metal narrower, which helps to form a filamentous morphology, thereby improving the wettability and fluidity of the filler metal. Further, the alloy melt is atomized into powder by controlling the gas atomization water cooling process, so as to obtain a self-lubricating filamentous nickel-based filler metal. The obtained filler metal has uniform composition and excellent wetting and diffusibility, and the filler metal can smoothly diffuse into the base metal, thereby reducing the generation of brittle phases and improving the mechanical properties of the welded joint of the nickel-based filler metal.

[0013] Preferably, in step S1, the chemical composition of the nickel-based filler metal is by mass percentage: Cr: 29.5%, Si: 4.0%, P: 6.0%, B: 0.125%, Ce: 0.15%, and the balance is Ni.

[0014] Preferably, in step S1, the alloy raw materials include Ni, Cr, Si, Ce elemental substances and Ni-P master alloy, Ni-B master alloy;

[0015] Preferably, the purity of the Ni, Cr, Si, Ce elemental substances and Ni-P master alloy, Ni-B master alloy is above 99.95%.

[0016] Preferably, in step S1, the alloy raw materials are added into an intermediate frequency electromagnetic induction melting furnace and melted under the protection of an inert gas;

[0017] Preferably, the melting temperature is 1375-1385°C.

[0018] Preferably, in step S2, the alloy melt is conveyed to an atomization device, and after flowing out of the heat preservation crucible, it is broken into mist-like droplets by the inert gas ejected from the gas atomization nozzle, and then atomized into powder by water cooling.

[0019] Preferably, the temperature of the inert gas is 80-90°C, the pressure is 27.8-28.2 MPa, the temperature of the water cooling cooling water is below 30°C, and the cooling water pressure is 1.6-2 MPa;

[0020] Preferably, the temperature of the inert gas is 85°C, the pressure is 28 MPa, the temperature of the water cooling cooling water is below 30°C, and the cooling water pressure is 1.8 MPa;

[0021] Preferably, the temperature of the heat-insulating crucible is 1145 - 1155 °C.

[0022] In the present invention, the powder preparation is carried out by the vacuum inert gas atomization method. First, Ni, Cr, Si, Ce elemental substances and Ni-P intermediate alloy, Ni-B intermediate alloy are selected for alloy preparation. Using an intermediate frequency induction melting furnace, the raw materials are melted under the protection of high-purity inert gas to obtain an alloy melt. When the temperature rises to the atomization temperature, at the same time, the heat-insulating crucible is heated by a high-frequency induction system, and the heating rate is synchronized with the melting rate, so that when the melt reaches the atomization temperature, the temperature of the heat-insulating crucible is suitable for powder preparation; the atomization temperature is precisely controlled, and the temperature of the melt in the melting furnace is controlled between 1375 - 1385 °C, and the temperature of the heat-insulating crucible is between 1145 - 1155 °C; high-purity argon can be used as the medium for atomization powder making. By the water bath heating method, the temperature of the atomization medium is maintained at 80 - 90 °C, and the gas output temperature is maintained at 80 - 90 °C through the water bath heating equipment and the coil system. After reaching the atomization conditions, the atomization powder making operation is carried out. The metal melt is gradually transferred from the melting crucible to the heat-insulating crucible, and at the same time, the atomization air flow is turned on for powder preparation. The atomization air pressure is 27.8 - 28.2 MPa, the water temperature of the cooling water of the atomization system is controlled below 30 °C, and the cooling water pressure is 1.6 - 2 MPa. After all the metal melt is atomized, wait for the temperature of the system and the powder material to drop to room temperature, and take out the powder material from the powder collection tank; by strictly controlling the above process parameters, the nickel-based filler metal alloy forms filaments during the atomization process. The change in temperature during this process will cause the powder to return to spherical powder, and it is impossible to obtain filamentous nickel-based filler metal.

[0023] Preferably, in step S2, it further includes screening the powder after atomization powder making, and then the filamentous nickel-based filler metal is obtained.

[0024] In the present invention, the proportion of the filamentous nickel-based filler metal in the powder after atomization powder making is about 10%.

[0025] The present invention also provides a self-lubricating filamentous nickel-based filler metal prepared by the above preparation method.

[0026] The present invention also provides an application of the above self-lubricating filamentous nickel-based filler metal in welding hard alloy and steel substrate.

[0027] Preferably, the brazing temperature is 1100 - 1200 °C, the heating rate is 10 - 15 °C / min, and the vacuum degree is 10 -2 -10 -3 Pa.

[0028] The beneficial effects of the present invention:

[0029] (1) In the present invention, by precisely controlling the modification of the filler metal composition and the atomization powder-making process, a filamentous Ni-Cr-P series nickel-based filler metal in a rapidly solidified state is prepared. It exhibits filamentous characteristics in its microscopic morphology. The filamentous powder has characteristics such as self-wetting and high diffusivity, which are different from the powder characteristics currently used in the industry. The filler metal can be formed without necessarily being prepared into a paste-like filler metal. Even when made into a paste-like filler metal, compared with traditional powder-like nickel-based filler metals, the addition amount of the additives in the paste-like filler metal is significantly reduced. In addition, due to its special morphological characteristics, it can supplement the application process for the existing nickel-based solder market, increasing the usage scenarios and application fields of nickel-based filler metals.

[0030] (2) In the present invention, the filler metal material composition is Ni as the balance, Cr content 29.5% ± 0.5%, Si content 4.0% ± 0.15%, P content 6.0% ± 0.15%, B content 0.125% ± 0.025%, Ce content 0.15% ± 0.05%; in the powder-making process, the melting temperature is controlled at 1380 ± 5 °C, the temperature of the holding crucible is between 1150 °C ± 5 °C, the atomization medium temperature is 85 °C ± 5 °C, the atomization air pressure is 28 ± 0.2 MPa, the water temperature of the cooling water in the atomization system is controlled below 30 °C, and the cooling water pressure is 1.8 MPa ± 0.2 MPa; the filamentous nickel-based filler metal prepared thus, as a new filler metal morphology, has self-lubricating properties that spherical powder does not have, which can greatly enhance the fluidity of the filler metal, significantly improve the wettability of the filler metal, and strengthen the mechanical properties of the joint after soldering of the filler metal. Description of the Drawings

[0031] Figure 1 SEM picture of the filamentous nickel-based filler metal described in Example 1 of the present invention. Detailed Embodiments

[0032] Next, the present invention will be described in detail through specific examples for the technical solutions, but it should be clearly stated that these examples are for illustrative purposes only and are not construed as limiting the scope of the present invention.

[0033] Example 1

[0034] This example presents a self-lubricating filamentous nickel-based filler metal, which is prepared by the following method:

[0035] (1) According to the chemical composition of the nickel-based filler metal, Ni, Cr, Si, Ce elemental substances with a purity greater than 99.99% and Ni-P master alloy, Ni-B master alloy are added to an intermediate frequency electromagnetic induction melting furnace in proportion and melted under the protection of argon gas. The melting temperature is 1380 °C to obtain an alloy melt;

[0036] Among them, the chemical composition of the nickel-based filler metal by mass percentage includes: Cr: 29.5%, Si: 4.0%, P: 6.0%, B: 0.125%, Ce: 0.15%, and the balance is Ni;

[0037] (2) Transport the alloy melt to the atomization equipment. After flowing out of the heat-preserving crucible, it is broken into mist-like droplets by the argon gas ejected from the gas atomization nozzle, and then atomized powder is obtained through water cooling. The powder is subjected to vibration screening to obtain the filamentous nickel-based filler metal;

[0038] Among them, the temperature of the heat-preserving crucible is 1150 °C, the temperature of the argon gas is 85 °C, the pressure is 28.0 MPa, the temperature of the water-cooling cooling water is below 30 °C, and the cooling water pressure is 1.8 MPa.

[0039] Place the filamentous nickel-based filler metal prepared in this example under a scanning electron microscope for observation. The results are as Figure 1 shown. It can be found that the nickel-based filler metal presents a filamentous characteristic in the microscopic morphology and is all at the nanoscale.

[0040] Example 2

[0041] This example presents a self-lubricating filamentous nickel-based filler metal, which is prepared by the following method:

[0042] (1) According to the chemical composition of the nickel-based filler metal, Ni, Cr, Si, Ce elemental substances with a purity greater than 99.99% and Ni-P master alloy, Ni-B master alloy are added to the intermediate frequency electromagnetic induction melting furnace in proportion, and melting is carried out under the protection of argon gas. The melting temperature is 1375 °C to obtain an alloy melt;

[0043] Among them, the chemical composition of the nickel-based filler metal by mass percentage includes: Cr: 29%, Si: 4.15%, P: 5.85%, B: 0.15%, Ce: 0.1%, and the balance is Ni;

[0044] (2) Transport the alloy melt to the atomization equipment. After flowing out of the heat-preserving crucible, it is broken into mist-like droplets by the argon gas ejected from the gas atomization nozzle, and then atomized powder is obtained through water cooling. The powder is subjected to vibration screening to obtain the filamentous nickel-based filler metal;

[0045] Among them, the temperature of the heat-preserving crucible is 1155 °C, the temperature of the argon gas is 80 °C, the pressure is 28.2 MPa, the temperature of the water-cooling cooling water is below 30 °C, and the cooling water pressure is 1.6 MPa.

[0046] Example 3

[0047] This example presents a self-lubricating filamentous nickel-based filler metal, which is prepared by the following method:

[0048] (1) According to the chemical composition of the nickel-based filler metal, Ni, Cr, Si, Ce elemental substances with a purity greater than 99.99% and Ni-P master alloy, Ni-B master alloy are added to an intermediate frequency electromagnetic induction melting furnace in proportion, and melted under the protection of argon gas. The melting temperature is 1385 °C to obtain an alloy melt;

[0049] Among them, the chemical composition of the nickel-based filler metal includes by mass percentage: Cr: 30%, Si: 3.85%, P: 6.15%, B: 0.1%, Ce: 0.2%, and the balance is Ni;

[0050] (2) The alloy melt is transported to an atomization device. After flowing out of the heat preservation crucible, it is broken into mist-like droplets by the argon gas ejected from the gas atomization nozzle, and then atomized powder is obtained through water cooling. The powder is subjected to vibrating screening to obtain the filamentous nickel-based filler metal;

[0051] Among them, the temperature of the heat preservation crucible is 1145 °C, the temperature of the argon gas is 90 °C, the pressure is 27.8 MPa, the water cooling cooling water temperature is below 30 °C, and the cooling water pressure is 2 MPa.

[0052] Comparative Example 1

[0053] This comparative example presents a nickel-based filler metal, which is prepared by the following method:

[0054] (1) According to the chemical composition of the nickel-based filler metal, Ni, Cr, Si elemental substances with a purity greater than 99.99% and Ni-P master alloy, Ni-B master alloy are added to an intermediate frequency electromagnetic induction melting furnace in proportion, and melted under the protection of argon gas. The melting temperature is 1380 °C to obtain an alloy melt;

[0055] Among them, the chemical composition of the nickel-based filler metal includes by mass percentage: Cr: 29.5%, Si: 4.0%, P: 6.0%, B: 0.125%, and the balance is Ni;

[0056] (2) The alloy melt is transported to an atomization device. After flowing out of the heat preservation crucible, it is broken into mist-like droplets by the argon gas ejected from the gas atomization nozzle, and then atomized powder is obtained through water cooling. The powder is subjected to vibrating screening to obtain the nickel-based filler metal;

[0057] Among them, the temperature of the heat preservation crucible is 1150 °C, the temperature of the argon gas is 85 °C, the pressure is 28.0 MPa, the water cooling cooling water temperature is below 30 °C, and the cooling water pressure is 1.8 MPa.

[0058] Comparative Example 2

[0059] This comparative example presents a nickel-based filler metal, which is prepared by the following method:

[0060] (1) According to the chemical composition of the nickel-based filler metal, Ni, Cr, Si, Ce elemental substances with a purity greater than 99.99% and Ni-P master alloy are added to an intermediate frequency electromagnetic induction melting furnace in proportion, and melted under the protection of argon gas. The melting temperature is 1380 °C to obtain an alloy melt;

[0061] Among them, the chemical composition of the nickel-based filler metal includes by mass percentage: Cr: 29.5%, Si: 4.0%, P: 6.0%, Ce: 0.15%, and the balance is Ni;

[0062] (2) The alloy melt is transported to an atomization device. After flowing out of the heat preservation crucible, it is broken into mist-like droplets by the argon gas ejected from the gas atomization nozzle, and then atomized powder is obtained through water cooling. The powder is subjected to vibrating screening to obtain the nickel-based filler metal;

[0063] Among them, the temperature of the heat preservation crucible is 1150 °C, the temperature of the argon gas is 85 °C, the pressure is 28.0 MPa, the water cooling cooling water temperature is below 30 °C, and the cooling water pressure is 1.8 MPa.

[0064] Comparative Example 3

[0065] This comparative example presents a nickel-based filler metal, which is prepared by the following method:

[0066] (1) According to the chemical composition of the nickel-based filler metal, Ni, Cr, Si, Ce elemental substances with a purity greater than 99.99% and Ni-P master alloy, Ni-B master alloy are added to an intermediate frequency electromagnetic induction melting furnace in proportion, and melted under the protection of argon gas. The melting temperature is 1380 °C to obtain an alloy melt;

[0067] Among them, the chemical composition of the nickel-based filler metal includes by mass percentage: Cr: 29.5%, Si: 4.0%, P: 6.0%, B: 0.125%, Ce: 0.15%, and the balance is Ni;

[0068] (2) The alloy melt is transported to an atomization device. After flowing out of the heat preservation crucible, it is broken into mist-like droplets by the argon gas ejected from the gas atomization nozzle, and then atomized powder is obtained through water cooling. The powder is subjected to vibrating screening to obtain the nickel-based filler metal;

[0069] Among them, the temperature of the heat preservation crucible is 1150 °C, the temperature of the argon gas is 95 °C, the pressure is 27.0 MPa, the water cooling cooling water temperature is below 30 °C, and the cooling water pressure is 1.8 MPa.

[0070] Comparative Example 4

[0071] This comparative example presents a nickel-based filler metal, which is prepared by the following method:

[0072] (1) According to the chemical composition of the nickel-based filler metal, Ni, Cr, Si, Ce elemental substances with a purity greater than 99.99% and Ni-P master alloy, Ni-B master alloy are added to an intermediate frequency electromagnetic induction melting furnace in proportion, and melted under the protection of argon gas. The melting temperature is 1380 °C to obtain an alloy melt;

[0073] Among them, the chemical composition of the nickel-based filler metal includes by mass percentage: Cr: 29.5%, Si: 4.0%, P: 6.0%, B: 0.125%, Ce: 0.15%, and the balance is Ni;

[0074] (2) The alloy melt is transported to an atomization device. After flowing out of the heat-insulating crucible, it is broken into mist-like droplets by the argon gas ejected from the gas atomization nozzle, and then atomized into powder through water cooling. The powder is subjected to vibration screening to obtain the filamentous nickel-based filler metal;

[0075] Among them, the temperature of the heat-insulating crucible is 1150 °C, the temperature of the argon gas is 85 °C, the pressure is 28.0 MPa, the water cooling water temperature is 40 °C, and the cooling water pressure is 1.8 MPa.

[0076] Application Example 1

[0077] The nickel-based filler metals prepared in Example 1 and Comparative Examples 1-4 are applied to solder paste formulation, and the solder paste formulation is shown in Table 1 below:

[0078] Table 1 Solder paste formulations corresponding to the nickel-based filler metals in the examples and comparative examples

[0079] Component Proportion Function Nickel-based solder 88.5％ Welding body Acrylic resin 4％ Binder Terpineol 6.5％ Solvent Fumed silica 0.6％ Thixotropic agent Benzotriazole 0.2％ Antioxidant Silicone surfactant 0.2％ Wetting improvement

[0080] The above solder paste is subjected to a wetting and spreading experiment to measure fluidity, carried out in accordance with the national standard GB / T11364-2008, and the substrate material is 304 stainless steel. The results are shown in Table 2 below:

[0081] Table 2 Detection results of the fluidity of the solder paste corresponding to the nickel-based filler metals in the examples and comparative examples

[0082] Solder type Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Spreading rate 97.8％ 93.4％ 89.5％ 94.1％ 85.3％ Wetting angle 14.3° 18.5° 19.1° 17.8° 21.3°

[0083] As can be seen from the above table, the fluidity and wettability of the solder paste corresponding to the nickel-based filler metal in the comparative example are lower than those of the filamentous nickel-based filler metal in the example, indicating that the filamentous nickel-based filler metal can improve the fluidity and wettability of the filler metal, can significantly increase the spreading efficiency of the solder paste, improve the interface quality during the welding process, and at the same time has a relatively large spreading area at room temperature, which can reduce the situation of solder paste overflow caused by high temperature during the welding process and improve the quality of welded parts.

[0084] Application Example 2

[0085] The nickel-based solders prepared in Example 1 and Comparative Examples 1-4 were applied to weld YG8 cemented carbide (with a thickness of 8 mm) and M2 high-speed steel (with a thickness of 10 mm). The welding method was vacuum brazing, the welding temperature was 1160 °C, the vacuum degree was 10 -2 Pa, the heating rate was 12 °C / min, and the thickness of the solder layer was 60 μm.

[0086] According to the regulations in the national standard GB / T6400-2007, the performance of the welded joints after the above welding was tested for shear strength on a universal testing machine, and the results shown in Table 3 were obtained.

[0087] Table 3 Shear strength of the welded joints corresponding to the nickel-based solders in the examples and comparative examples

[0088]

[0089] As can be seen from Table 1 above, the shear strength of the welded joints corresponding to the powdered nickel-based solder in the comparative example was much lower than that of the filamentous nickel-based solder described in the example, indicating that the filamentous nickel-based solder can improve the wettability between the solder and the base metal and strengthen the mechanical properties of the solder joint after welding.

[0090] As described above, only the preferred specific embodiments of the present invention are provided, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a self-lubricating filamentary nickel-based solder, characterized in that: The steps include: S1. Smelting the alloy raw materials according to the chemical composition of the nickel-based solder to obtain an alloy melt; S2, atomizing and powdering the alloy melt by a gas atomization and water cooling process to obtain the filamentous nickel-based solder; The chemical composition of the nickel-based solder, calculated by mass percentage, includes: Cr: 29-30%, Si: 3.85-4.15%, P: 5.85-6.15%, B: 0.1-0.15%, Ce: 0.1-0.2%, and Ni as the remainder.

2. The method for preparing the self-lubricating filamentary nickel-based solder according to claim 1, characterized in that: In step S1, the chemical composition of the nickel-based solder, by mass percentage, includes: Cr: 29.5%, Si: 4.0%, P: 6.0%, B: 0.125%, Ce: 0.15%, and Ni balance.

3. The method for preparing the self-lubricating filamentary nickel-based solder according to claim 1 or 2, characterized in that: In step S1, the alloy raw materials include Ni, Cr, Si, Ce single substances and Ni-P master alloy and Ni-B master alloy; Preferably, the purity of the Ni, Cr, Si, Ce single substances and the Ni-P master alloy and the Ni-B master alloy is above 99.95%.

4. The method for preparing the self-lubricating filamentary nickel-based solder according to any one of claims 1 to 3, characterized in that: In step S1, the alloy raw material is added into a medium frequency electromagnetic induction melting furnace and melted under the protection of an inert gas; Preferably, the smelting temperature is 1375-1385°C.

5. The method for preparing the self-lubricating filamentary nickel-based solder according to any one of claims 1 to 4, characterized in that: In step S2, the alloy melt is transported to an atomization device, flows out of a heat-insulating crucible, and is broken into mist droplets by an inert gas ejected from an atomization nozzle, and then atomized and powdered by water cooling.

6. The method for preparing the self-lubricating filamentary nickel-based solder according to claim 5, characterized in that: The inert gas temperature is 80-90°C, the pressure is 27.8-28.2MPa, the water-cooled cooling water temperature is below 30°C, and the cooling water pressure is 1.6-2MPa; Preferably, the inert gas temperature is 85°C, the pressure is 28MPa, the water-cooled cooling water temperature is below 30°C, and the cooling water pressure is 1.8MPa; Preferably, the temperature of the insulating crucible is 1145-1155°C.

7. The method for preparing the self-lubricating filamentary nickel-based solder according to any one of claims 1 to 6, characterized in that: Step S2 also includes screening the powder after atomization to obtain the filamentous nickel-based solder.

8. A self-lubricating filamentary nickel-based solder prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the self-lubricating filamentary nickel-based solder according to claim 8 in welding hard alloy and steel substrate.

10. The use of the self-lubricating filamentary nickel-based brazing filler metal according to claim 9 in brazing hard alloy and steel substrate, characterized in that: The brazing temperature is 1100-1200°C, the heating rate is 10-15°C / min, and the vacuum degree is 10 -2 -10 -3 Pa.

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