Method for gap brazing or defect repair of a metal piece

Abstract

This invention relates to a method for gap brazing or defect repair of metal parts, wherein the method includes the following steps: filling the area to be welded of the metal part with a first paste and drying it; the area to be welded is a gap or defect; the first paste is prepared by a first mixed powder and an adhesive; the first mixed powder includes filler powder and solder powder in a mass ratio of 2:8-3:7; removing part of the first paste filled in the area to be welded to form a void in the area to be welded; filling the void in the area to be welded with a second paste and drying it; the second paste is prepared by a second mixed powder and an adhesive; the second mixed powder includes filler powder and solder powder in a mass ratio of 4:6-6:4; covering the outer surface of the area to be welded with the first paste and drying it; and then performing vacuum brazing on the metal part. This invention is mainly used to obtain high-quality, dense welds after gap brazing or defect repair of metal parts.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a method for gap brazing or defect repair of metal parts. Background Technology

[0002] With the increasing demand for efficient and low-cost manufacturing of aero engines and gas turbines, the issue of reducing the manufacturing and repair costs of their key high-temperature alloy components has become increasingly prominent. Currently, in order to improve the qualification rate of component manufacturing, reduce manufacturing difficulty, and cut production costs, high-temperature alloy components for engines are increasingly being produced through post-processing methods (such as brazing) during the design and development process. However, this poses a severe challenge to the improvement of processing technology, especially brazing technology.

[0003] For large and complex structural components, metallurgical defects are unavoidable during manufacturing due to the high difficulty of the process. To improve the manufacturing pass rate, repair techniques are needed to restore these metallurgical defects, reduce scrap, and lower costs. Furthermore, with the increasing thrust and frequency of use of aero-engines and gas turbines, damage to hot-end engine components is becoming increasingly severe. During scheduled engine overhauls, if severe damage, large defects, and numerous defects are found, replacement with new parts is often used to ensure reliability. However, this method is not only expensive but also consumes large amounts of rare metal resources and energy, resulting in a significant environmental burden. Therefore, there is an urgent need for a low-cost, highly reliable, and rapid defect repair method.

[0004] For example, in the brazing of the process holes at the blade tip, as the hole diameter design becomes larger, although the manufacturing difficulty of the blade is reduced and the blade manufacturing qualification rate is improved, the difficulty of brazing the process holes with larger diameters increases significantly. Existing technology has a good sealing effect on small and medium diameter process holes, but when sealing large diameter process holes, due to the large gap to be welded, it is easy for the surface to sink, the brazing filler metal to collapse, or even flow into the inner cavity due to the gravity of the solder. Moreover, due to the solidification and shrinkage of the solder, large-sized shrinkage cavities appear inside the weld.

[0005] For example, during the manufacturing process of integral turbine disks, it is difficult to avoid large-sized defects in certain areas due to undercasting. In order to improve the pass rate, it is necessary to repair these defects. Existing repair technologies are effective for repairing smaller defects, but the larger the defect size, the more difficult the repair becomes, and the more likely it is that surface solder will be lost or the internal solder will not be welded.

[0006] In summary, there is an urgent need for high-quality, large-gap brazing and large-size defect repair for forged, cast, powder metallurgy, and additively manufactured parts. Therefore, there is a pressing need to develop a method for gap brazing or defect repair of metal parts. Summary of the Invention

[0007] In view of this, the present invention provides a method for gap brazing or defect repair of metal parts, the main purpose of which is to obtain high-quality dense welds after gap brazing or defect repair of metal parts.

[0008] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0009] On one hand, embodiments of the present invention provide a method for gap brazing or defect repair of metal parts, which includes the following steps:

[0010] Step of filling the first paste: Fill the part to be welded of the metal part with the first paste, so that the first paste fills the part to be welded and compacts it, and then performs a drying treatment; wherein, the part to be welded is a gap or defect; wherein, the first paste is prepared by a first mixed powder and an adhesive; wherein, the first mixed powder includes filler powder and solder powder in a mass ratio of 2:8-3:7.

[0011] Partial removal of the first paste step: Remove part of the first paste that is filled in the area to be soldered to create a void in the area to be soldered;

[0012] The second paste filling step involves filling the gaps in the area to be soldered with the second paste, compacting it, and then drying it. The second paste is prepared from a second mixed powder and an adhesive. The second mixed powder comprises filler powder and solder powder in a mass ratio of 4:6 to 6:4.

[0013] First paste covering step: Cover the outer surface of the metal part to be welded after the second paste filling step with the first paste, dry it, apply a flow barrier around the paste, and dry it to obtain the metal part after the first paste covering step.

[0014] Vacuum brazing step: Vacuum brazing is performed on the metal parts after the first paste covering step to obtain metal parts with gap brazing or defect repair.

[0015] Preferably, the metal part is a high-temperature alloy part or a stainless steel part; and / or if the part to be welded is a gap that needs to be brazed, the diameter or width of the gap is at most 2.5 mm; and / or if the part to be welded is a defect, the depth of the defect is at most 10 mm.

[0016] Preferably, the chemical composition of the solder, by weight fraction, is as follows:

[0017] Cr: 7-15wt%, W: 3-8wt%, B: 0.9-4.5wt%, Si: 0-3wt%, Co: 0-10wt%, Al: 0-4.5wt%, Ta: 0-6wt%, Mo: 0-4.5wt%, Ti: 0-5wt%, balance Ni;

[0018] Preferably, when the metal part contains a first element; wherein the first element is any one of Co, Al, Ta, Mo, and Ti: the content of the first element in the solder does not exceed the content of the first element in the metal part;

[0019] Preferably, when the metal part does not contain the first element, wherein the first element is any one of Co, Al, Ta, Mo, and Ti: the first element is not added to the solder.

[0020] Preferably, the solder powder has a particle size of -150 mesh; and / or

[0021] The filler powder has a particle size of -100 mesh; and / or

[0022] The chemical composition of the filler powder may be the same as or different from that of the metal part, preferably the same; and / or

[0023] In the first paste, the mass ratio of the first mixed powder to the adhesive is 9:1-12:1; and / or

[0024] In the second paste, the mass ratio of the second mixed powder to the adhesive is 9:1 to 12:1.

[0025] Preferably, prior to the step of filling the first paste, the method further includes:

[0026] Cleaning steps for the area to be welded: Use anhydrous ethanol or acetone to clean the area of ​​the metal part to be welded that needs gap brazing or defect repair.

[0027] Preferably, if there is a layer of dirt on the part to be welded, the dirt is removed first by surface treatment, and then the part to be welded is cleaned.

[0028] Preferably, in the step of filling the first paste:

[0029] The first paste must fill the area to be soldered to the required extent that: the first paste completely fills the area to be soldered and extends beyond the original surface of the metal part; and / or

[0030] The drying process is carried out by either natural drying or oven drying.

[0031] Preferably, in the step of removing part of the first paste:

[0032] Remove the first paste that extends beyond the prototype surface from the metal part after the first paste filling step; then remove a portion of the first paste that was filled in the area to be soldered to create a gap in the area to be soldered; and / or

[0033] The volume of the gap accounts for 40-60% of the volume of the area to be welded; and / or

[0034] If one side of the part to be welded is an opening, remove part of the first paste from the opening; if the part to be welded is a penetrating gap or defect, remove part of the first paste from one or both openings of the part to be welded.

[0035] Preferably, in the step of filling the second paste, the filling degree of the second paste at the area to be welded must meet the following requirements: the second paste fills the gaps in the area to be welded and extends beyond the prototype surface of the metal part; and / or

[0036] In the step of covering the first paste: after removing the second paste that extends beyond the prototype surface from the metal part treated in the step of filling the second paste, the first paste is applied to the outer surface of the area to be soldered; and / or

[0037] In the step of covering the first paste: the volume of the first paste covering the outer surface of the part to be soldered is not less than twice the volume of the part to be soldered.

[0038] Preferably, in the vacuum brazing step:

[0039] The metal parts treated with the first paste are placed in a vacuum furnace, and the vacuum pressure is evacuated to no higher than 0.04 Pa. The metal parts are heated to 1040-1260°C at a heating rate of no higher than 15°C / min, and held at 1040-1260°C for 10-240 min. After the holding time is completed, the parts are cooled to obtain metal parts with gap brazing or defect repair.

[0040] Preferably, during the heating process, if the vacuum pressure exceeds 0.04 Pa, the heating is paused, and the heating continues when the vacuum pressure drops below 0.04 Pa.

[0041] Preferably, after the vacuum brazing step, a surface treatment step is further included: polishing the excess brazing filler metal on the outer surface of the metal part after gap brazing or defect repair to the original surface state; or retaining part or all of the brazing filler metal buildup or brazing leads as required; and / or

[0042] The welded parts of the metal parts after gap brazing or defect repair have no unwelded defects, and the brazing matrix is ​​a γ-Ni solid solution rich in γ′ precipitate phase, with borides distributed and no eutectic structure; wherein the shape of the borides includes skeleton-like, blocky, and granular.

[0043] Compared with the prior art, the gap brazing or defect repair method for metal parts of the present invention has at least the following beneficial effects:

[0044] This invention provides a method for gap brazing or defect repair of metal parts. To achieve high-quality large-gap brazing and large-size defect repair of metal parts, and to obtain high-performance, dense welds, this invention combines two pastes (i.e., two mixed brazing fillers) with different filler-to-solder ratios. These pastes are applied sequentially to the area to be welded, and finally, a further application is made to the outside of the area. This invention cleverly utilizes the quick-drying and curing characteristics of the pastes. It first fills the area to be welded with a first paste with a high solder ratio, removes some after drying, then fills it with a second paste with a high filler ratio. Finally, a second paste with a high solder ratio is applied again to the outside (outer surface) of the area to be welded. This achieves a gradient change in the filler material ratio and composition. Specifically, the weld core and the weld outer surface are filled with the first paste, which has better flow and gap-filling capabilities, while a third paste (the second paste with a higher filler ratio) with stronger sintering capabilities and easier fixation in its original position is sandwiched between them, creating a three-layer structure. By utilizing this gradient change, during subsequent vacuum brazing, the high-flowability brazing filler metal on both sides can assist in wetting the low-flowability brazing filler metal in the middle, reducing the porosity of the sintered brazing. At the same time, the middle brazing filler metal can help solidify the filler metal on both sides, making it less prone to leakage, thereby avoiding overflow or depressions. When repairing penetrating defects, a five-layer structure can be achieved. After the steps of filling the first paste, removing the first paste, filling the second paste, and covering the first paste according to the present invention, the following structure is formed: the first paste is filled in the central area of ​​the area to be welded, the two sides of the area to be welded are filled with the second paste, and the outer sides are then coated with the first paste again. This ensures sufficient support and solidification while also achieving sufficient wetting and gap filling of the brazing filler metal, thus balancing the contradiction between the filling and flowability of the brazing filler metal during large gap brazing or repair.It should be noted that if the method described above is not followed, and instead only a mixture of filler and solder in a single ratio is placed inside the area to be welded as the first layer, even if a sufficient amount of highly fluid solder is applied to the outside of the area to be welded as the second layer, this ordinary two-layer structure cannot simultaneously guarantee the overall support and density of the large gap weld. This is because to ensure the firmness of the solder and avoid excessive loss, the filler material in the first layer needs to have good sintering properties, and a solder with a higher filler ratio should be used as the filler material. However, this results in a lack of fluidity in the first layer of solder. For brazing or repairing welds with general gap sizes, the external... The second layer of highly fluid brazing filler metal can fill the gap through capillary action, but its effective range is limited. When the area to be welded is large, the weld core will exhibit a loose and porous structure that is drastically different from the dense external structure, making it difficult to detect through general visual inspection or fluorescent penetrant testing. This poses a potential risk of weld failure during service. To ensure the fluidity and wettability of the brazing filler metal and reduce these weld voids, the proportion of solder in the filler material needs to be increased. This generally does not cause problems for brazing smaller gaps, but when the gap to be brazed is too large, it can easily lead to weld depressions and collapses, or even large-area solder loss. Therefore, for high-quality repair of large gaps and large defects, multi-layer filling with a mixture of solder and filler metal in different proportions is extremely important.

[0045] Furthermore, in both the filling of the first and second pastes, the present invention involves filling and compacting the material. Especially when applying the first paste to the area to be soldered, the area is first completely filled and compacted, then a portion of the first paste is removed from the area to create gaps for the second paste. This operation is crucial for the success of large-gap brazing or the repair of large-size defects. If this step is not followed, and each layer of solder is applied directly according to the target amount, filling only a portion of the volume of the area to be soldered with the first paste (first layer of solder), the structural limitations prevent compaction, resulting in insufficient filling of the area to be soldered, or even localized areas without solder that are difficult to detect in time. When a second layer of solder paste (the second layer of brazing filler metal) is added to the remaining volume of the area to be soldered, even with sufficient compaction, it cannot compensate for the voids already created by the first layer of brazing filler metal. These voids are eventually inherited into the weld. This is because, during high-temperature brazing, the second layer of brazing filler metal mainly plays a role in sintering and solidification. Therefore, even if a third layer of brazing filler metal with a volume of not less than twice that of the area to be soldered is applied to the outside of the area to be soldered, it is difficult to fill the voids of the first layer of brazing filler metal beyond the second layer.

[0046] Furthermore, in the preparation of the first and second pastes, the weight ratio of the mixed powder to the binder is 9:1-12:1. In order to ensure the basic fluidity of the paste and the density and uniformity of the powder in the paste, an appropriate ratio is adopted. If the proportion of mixed powder in the solder paste is too low, exceeding the above-mentioned range, the solid content of the paste will be insufficient to support its full and uniform distribution on the area to be soldered. Some powder may even exhibit severe agglomeration, further exacerbating the already low density and making it even more uneven. Combined with the collapse caused by the evaporation of the binder in the paste, this can easily lead to large defects or excessive flow after soldering. If the proportion of powder in the paste is too high, exceeding the above-mentioned range, the insufficient binder content will result in poor paste flowability, drastically increasing the difficulty of the filling operation. Significant additional pressure is required to complete the solder paste filling, especially when the shape of the area to be soldered is irregular, greatly increasing the resistance to the solder paste's insertion path. This greatly increases the instability of the coating process, easily leading to incomplete filling in certain areas, and excessive pressure may also cause the solder to accidentally enter non-soldering areas (such as internal cavities). Therefore, the weight ratio of powder to binder should be strictly controlled within the range of 9:1 to 12:1.

[0047] Furthermore, the filler composition used in the mixed powder of the present invention is preferably consistent with that of the metal part, ensuring the consistency of the matrix structure and properties of the filled area with those of the metal part. The solder powder used in conjunction is based on the Ni-Cr-WB quaternary system. The addition of Cr and W elements ensures the corrosion resistance, oxidation resistance and high-temperature strength of the weld matrix. The addition of B element gives it excellent fluidity and wettability. In addition, the solder powder also preferably contains an appropriate amount of other alloying elements that are the same as the base alloy, to obtain better matching with the base alloy and filler powder. Thus, during the brazing process, the micropores in the middle of the filler skeleton are further filled by capillary action to obtain a high-performance dense joint.

[0048] Furthermore, the solder particles selected in this invention are relatively fine (-150 mesh, particle size smaller than the aperture of a 150 mesh sieve), while the filler particles are relatively coarse (-100 mesh, particle size smaller than the aperture of a 100 mesh sieve). This combination helps the filler to better act as a large-size skeleton, preventing it from being prematurely melted away by the molten solder at high temperatures, thus losing its supporting effect and leading to weld collapse and brazing filler metal overflow. Moreover, the coarser filler particles, acting as a skeleton, also provide a rich source of reinforcing elements. Through interdiffusion, the solder further absorbs these reinforcing elements from the filler, thereby enhancing weld strength. Simultaneously, it reduces the content of low-melting-point elements in the solder itself, increasing the solder remelting temperature and preventing the formation of low-melting-point eutectics. Therefore, the brazed seam matrix formed after brazing is a γ-Ni solid solution rich in γ′ precipitate phase, with high-melting-point skeletal / massive / granular borides distributed therein. These borides play a role in improving strength by hindering dislocation slip, and there is no low-melting-point eutectic structure in the brazed seam, which greatly avoids the risk of brazed seam weakening when the parts are in over-temperature service.

[0049] In summary, the present invention provides a method for gap brazing or defect repair of metal parts. By using a mixed brazing filler metal with different filler and solder ratios, it achieves high-quality repair of large gap brazing and large-size defects, resulting in joints with excellent structure and performance. This greatly improves the manufacturing qualification rate of parts, significantly reduces the replacement frequency of engine parts, extends service life, reduces production costs and environmental burden, contributes to the development of a green circular economy, and has considerable application prospects.

[0050] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0051] Figure 1 This is a partial X-ray photograph of the blade tip of the part after the cover plate hole was sealed and welded in Example 1;

[0052] Figure 2 These are photographs of the original crack defects in the high-temperature alloy parts in Example 2;

[0053] Figure 3 These are photographs of the original crack defects in the high-temperature alloy parts in Example 3;

[0054] Figure 4 This is a photograph of the high-temperature alloy part in Example 3 after the defect was repaired;

[0055] Figure 5 This is a photograph of the gap to be welded in the stainless steel part in Example 5;

[0056] Figure 6 This is a photograph of the original gap after the stainless steel parts were brazed in Example 5;

[0057] Figure 7 These are micrographs of the repaired areas of the high-temperature alloy parts in Example 7.

[0058] Figure 8 This is another microstructure photograph of the repaired area after the high-temperature alloy part was repaired in Example 7;

[0059] Figure 9 This is a photograph of the brazed area after the sealing brazing in Comparative Example 1;

[0060] Figure 10 This is a photograph of the brazing filler metal that flowed onto the outside of the part after the sealing brazing process in Comparative Example 1.

[0061] Figure 11 This is a photo of the defect in Comparative Example 3 after the defect has been repaired. Detailed Implementation

[0062] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0063] The solution of this invention enables high-quality brazing of large gaps or repair of large defects, thereby significantly reducing overall manufacturing and repair costs. This will help promote the efficient and low-cost manufacturing of aero-engines and gas turbines, and has broad application prospects. The solution of this invention is specifically as follows:

[0064] On one hand, embodiments of the present invention provide a method for gap brazing or defect repair of metal parts, which includes the following steps:

[0065] Cleaning steps for the area to be welded: Clean the area to be welded, which requires gap brazing or defect repair, with anhydrous ethanol or acetone. If there is a stubborn layer of dirt that is difficult to clean directly, remove the dirt first by mechanical grinding or sandblasting, and then clean it with anhydrous ethanol or acetone.

[0066] The first paste filling step involves filling the metal part with the first paste to be welded, making the first paste fill the part to be welded and compacting it, and then drying it; wherein the part to be welded is a gap or defect; wherein the first paste is prepared by a first mixed powder and an adhesive; wherein the first mixed powder includes filler powder and solder powder in a mass ratio of 2:8-3:7.

[0067] Preferably, the preparation steps of the first paste are as follows: the first mixed powder and the adhesive are uniformly mixed at a weight ratio of 9:1 to 12:1 to obtain the first paste. Preferably, the adhesive is an alcohol-based adhesive or a water-based adhesive.

[0068] It should be noted that the chemical composition of the solder powder used in this invention is as follows: by weight percentage, the solder includes the following chemical components: Cr: 7-15wt%, W: 3-8wt%, B: 0.9-4.5wt%, Si: 0-3wt%, Co: 0-10wt%, Al: 0-4.5wt%, Ta: 0-6wt%, Mo: 0-4.5wt%, Ti: 0-5wt%, with the balance being Ni; preferably, when the metal part contains a first element; wherein the first element is any one of Co, Al, Ta, Mo, and Ti: the content of the first element in the solder does not exceed the content of the first element in the metal part; preferably, when the metal part does not contain a first element; wherein the first element is any one of Co, Al, Ta, Mo, and Ti: the first element is not added to the solder.

[0069] The solder powder has a particle size of -150 mesh; the filler powder has a particle size of -100 mesh. The chemical composition of the filler powder may be the same as or different from that of the metal part, preferably the same.

[0070] When the area to be welded is a gap requiring brazing, the maximum diameter or width of the gap is 2.5 mm. If the area to be welded is a defect, the maximum depth of the defect is 10 mm. It should be noted that: for metal parts requiring brazing, the width of the brazing gap should not exceed 2.5 mm; if the metal part has a defect that needs repair, the depth of the defect should not exceed 10 mm.

[0071] Preferably, this step specifically involves: filling the area to be soldered with a first solder paste and compacting it, ensuring the filling depth is no less than that of the prototype surface of the part's outer surface, followed by natural drying or high-temperature drying. Here, the term "prototype surface" in this invention refers to the surface of the part as specified in the original drawing, also known as the original surface.

[0072] Partial removal of the first paste step: Remove part of the first paste that is filled in the area to be soldered to create a void in the area to be soldered.

[0073] Preferably, this step specifically involves: after removing the solder beyond the outer surface of the metal part, continuing to remove 50% ± 10% of the solder inside the part to be welded from the side closest to the outer surface (i.e., emptying 50% ± 10% of the total volume of the part to be welded). If the part to be welded is a penetrating defect exposed on both sides, remove 50% ± 10% of the solder inside the part to be welded from one side, or remove 25% ± 5% of the solder inside the part to be welded from both sides of the part to be welded (again, emptying 50% ± 10% of the total volume of the part to be welded).

[0074] The second paste filling step involves filling the gaps in the area to be soldered with the second paste, compacting it, and then drying it. The second paste is prepared from a second mixed powder and an adhesive. The second mixed powder comprises filler powder and solder powder in a mass ratio of 4:6 to 6:4.

[0075] Preferably, this step specifically involves: filling the cleared gaps in the area to be soldered with the second paste and compacting it, ensuring that the filling degree is not lower than that of the original surface of the outer surface of the part, and then allowing it to dry naturally or at high temperature.

[0076] Preferably, the preparation steps of the second paste are as follows: the second mixed powder and the adhesive are uniformly mixed at a weight ratio of 9:1 to 12:1 to form the second paste. Preferably, the adhesive is an alcohol-based adhesive or a water-based adhesive.

[0077] It should be noted that the composition and particle size of the filler powder and solder powder in the second mixed powder in this step are the same as those in the first paste filling step.

[0078] First paste covering step: The first paste is applied to the outer surface of the metal part to be welded after the second paste filling step. After drying, a flow barrier is applied around the paste and then dried to obtain the metal part after the first paste covering step.

[0079] Preferably, the step specifically involves: removing the solder that extends beyond the prototype surface of the outer surface of the part; applying a first solder paste to the outer surface of the area to be soldered, with the amount applied not less than twice the volume of the area to be soldered, and allowing it to air dry or be dried at high temperature; applying a flow-blocking agent around the solder and allowing it to air dry or be dried at high temperature.

[0080] Vacuum brazing step: Vacuum brazing is performed on the metal parts after the first paste covering step to obtain metal parts with gap brazing or defect repair.

[0081] Preferably, this step specifically involves: placing the metal part covered by the first paste step into a vacuum furnace, evacuating it to a vacuum pressure not exceeding 0.04 Pa, heating the furnace to 1040-1260°C at a rate not exceeding 15°C / min, holding it at that temperature for 10-240 min, and then cooling it to below 100°C by furnace cooling, air cooling, or a combination of furnace cooling and air cooling before removing it from the furnace. If the vacuum pressure of the furnace exceeds 0.04 Pa during the heating process, the heating can be paused until the vacuum pressure drops below 0.04 Pa before resuming the heating process. It is also permissible to add a heat preservation step during the heating stage.

[0082] Surface treatment steps: After gap brazing or defect repair, the excess brazing material on the outer surface of the brazed or repaired part is piled up and polished to the original surface state, or some or all of the brazing material pile or brazing foot is retained according to specific technical requirements; preferably, the part is sandblasted before delivery.

[0083] It should be noted that the above-mentioned method of the present invention can achieve large-gap brazing or repair of large-size defects on high-temperature alloy parts or stainless steel parts. The maximum brazing gap size can reach 2.5mm, the maximum repaired defect size can reach 10mm, and the welded part is inspected after welding to find no unwelded defects and no brazing filler metal flows into the non-welded area.

[0084] The present invention will be further illustrated below with specific embodiments:

[0085] Example 1

[0086] This embodiment describes the sealing brazing of the tip cover plate hole in a high-temperature alloy component. The cover plate hole is a gap with a diameter of 1.6 mm; sealing this size hole is considered large-gap brazing. The high-temperature alloy component is a DD5 alloy turbine blade cast in a directional single-crystal furnace, and its chemical composition is as follows:

[0087] Cr: 7wt%, Co: 7.5wt%, W: 5wt%, Ta: 6.5wt%, Al: 6wt%, Mo: 1.5wt%, Re: 3wt%, Hf: 0.15wt%, Ni is the balance.

[0088] The chemical composition of the solder powder used in this embodiment is as follows:

[0089] Cr: 8wt%, W: 7.85wt%, B: 3.5wt%, Si: 1.5wt%, Al: 2wt%, Mo: 1.5wt%, Ni is the balance; the particle size of the solder powder is -150 mesh.

[0090] The chemical composition of the filler powder used in this embodiment is as follows:

[0091] Cr: 7wt%, Co: 7.5wt%, W: 5wt%, Ta: 6.5wt%, Al: 6wt%, Mo: 1.5wt%, Re: 3wt%, Hf: 0.15wt%, Ni is the balance.

[0092] The particle size of the filler powder is -100 mesh.

[0093] In addition, the ingredients of the first paste are as follows: filler powder and solder powder are uniformly mixed in a mass ratio of 3:7 to form a first mixed powder, and the first mixed powder is uniformly mixed with NICROBRAZ S-BINDER adhesive in a mass ratio of 11:1 to form a first paste.

[0094] The second paste is formulated as follows: filler powder and solder powder are uniformly mixed in a 5:5 mass ratio to form a second mixed powder. The second mixed powder is then uniformly mixed with NICROBRAZ S-BINDER adhesive in an 11:1 mass ratio to form the second paste.

[0095] The method in this embodiment mainly includes the following steps:

[0096] Cleaning steps for the area to be welded: Use 180-mesh corundum sand at a pressure of 0.2MPa to blow sand onto the cover plate hole area of ​​the part, and then clean it with anhydrous ethanol.

[0097] Step 1: Fill the first paste into the hole of the part cover plate and compact it. After filling, the outer surface of the cover plate will have a height higher than the prototype surface. Allow it to dry naturally.

[0098] Steps for filling the second paste: After removing the solder outside the part cover plate, continue to remove 50% of the first paste from the inside of the cover plate hole (error controlled within ±10%) to form a gap; fill the gap with the second paste and compact it. After filling, the outer surface of the cover plate will have a height higher than the prototype surface, and allow it to dry naturally.

[0099] Steps for applying the first solder paste: Remove any solder (second solder paste) that extends beyond the cover plate of the component; apply the first solder paste to the surface of the cover plate hole, applying an amount twice the volume of the cover plate hole, and allow it to air dry. Apply a flow-retardant around the solder and allow it to air dry.

[0100] Vacuum brazing steps: Place the parts in a vacuum furnace, evacuate to a vacuum pressure not exceeding 0.04 Pa, heat the furnace to 1180°C at a rate of 15°C / min, and hold at 1180°C for 10 minutes. After holding, purge with argon gas and cool to below 100°C before removing from the furnace.

[0101] Surface treatment steps: pile up excess brazing filler metal on the outer surface of the cover plate hole and polish it to the original surface state, and use 180-mesh corundum sand to blow sand on the part at a pressure of 0.2MPa.

[0102] The cover plate hole of the part was successfully sealed. Figure 1 The image shown is a partial X-ray photograph of the blade tip of the component after the cover plate hole has been sealed. Figure 1 The circled area in the diagram represents the original cover plate hole. It can be seen that the brazing filler metal fully fills the cover plate hole, with no unwelded defects and no overflow in the non-welded areas of the inner cavity. Therefore, this embodiment successfully achieved a high-quality brazing connection for a gap of 1.6mm.

[0103] Example 2

[0104] This embodiment describes the repair of crack defects in a high-temperature alloy component. The high-temperature alloy component is a DZ640M alloy guide vane, cast in a vacuum induction furnace, with the following chemical composition:

[0105] Cr: 25wt%, Ni: 10wt%, W: 8wt%, Ta: 0.3wt%, B: 0.01wt%, C: 0.5wt%, Mo: 0.2wt%, Al: 0.9wt%, Ti: 0.1wt%, Zr: 0.2wt%, Co is the balance. The rim plate of this high-temperature alloy part exhibits non-penetrating crack defects, such as... Figure 2 As shown, the depth of the crack defect is 2.2 mm.

[0106] The chemical composition of the solder powder used in this embodiment is as follows:

[0107] Co: 8wt%, Cr: 8wt%, W: 7.85wt%, B: 3wt%, Mo: 0.2wt%, Al: 0.9wt%, Ti: 0.1wt%, Si: 3wt%, Ni as balance; the particle size of the solder powder is not greater than 100μm.

[0108] The particle size of the solder powder is -150 mesh.

[0109] The chemical composition of the filler powder used in this embodiment is as follows:

[0110] Cr: 25wt%, Ni: 10wt%, W: 8wt%, Ta: 0.3wt%, B: 0.01wt%, C: 0.5wt%, Mo: 0.2wt%, Al: 0.9wt%, Ti: 0.1wt%, Zr: 0.2wt%, Co is the balance.

[0111] The particle size of the filler powder is -100 mesh.

[0112] In addition, the ingredients of the first paste are as follows: filler powder and solder powder are uniformly mixed in a ratio of 2:8 to form a first mixed powder, and the first mixed powder is uniformly mixed with NICROBRAZ S-BINDER adhesive in a weight ratio of 10:1 to form the first paste.

[0113] The second paste is formulated as follows: filler powder and solder powder are uniformly mixed in a 6:4 ratio to form a second mixed powder. The second mixed powder is then uniformly mixed with NICROBRAZ S-BINDER adhesive in a 12:1 weight ratio to form the second paste.

[0114] The method in this embodiment mainly includes the following steps:

[0115] Cleaning steps for the area to be welded: Use 140-mesh corundum sand at a pressure of 0.4 MPa to blow sand onto the defective area of ​​the part, and then clean it with anhydrous ethanol.

[0116] Step 1: Fill the defect area to be repaired with the first paste and compact it. The filling degree should be slightly higher than the original surface of the defect. Then dry it at 100℃ for 20 minutes.

[0117] Steps for filling with the second paste: After removing the solder that extends beyond the outer surface of the part, continue to remove 50% of the solder inside the defect from the side closest to the outer surface (with an error controlled within ±10%); fill the gap in the part to be soldered with the second paste and compact it, ensuring the filling degree is slightly higher than the outer surface of the part, and dry it at 100°C for 10 minutes.

[0118] Steps for applying the first paste: Remove the solder that extends beyond the prototype surface of the part's outer surface; apply the first paste to the outer surface of the defect to be repaired, with an application amount twice the volume of the area to be soldered, and dry at 100°C for 10 minutes; apply a flow-blocking agent around the solder and dry at 100°C for 10 minutes.

[0119] Vacuum brazing steps: Place the parts in a vacuum furnace, evacuate to a vacuum pressure not exceeding 0.04 Pa, heat the furnace to 1120°C at a rate of 10°C / min, hold at 1120°C for 20 minutes, and after holding, purge with argon gas and cool to below 100°C before removing from the furnace.

[0120] Surface treatment steps: The excess brazing filler metal on the outer surface of the repair area is piled up and polished to the original surface state, and the part is sandblasted with 140-mesh corundum sand at a pressure of 0.4MPa.

[0121] In Example 2, the large-sized non-penetrating crack defect of the high-temperature alloy part was successfully repaired. The repaired part had no unwelded defects and no brazing filler metal flowed into the non-welded area.

[0122] Example 3

[0123] This embodiment describes the repair of crack defects in a high-temperature alloy component. The high-temperature alloy component in this embodiment is a K4951 alloy casing, cast in a vacuum precision casting furnace, with the following chemical composition:

[0124] Cr: 9wt%, Co: 5wt%, Al: 6wt%, W: 3.5wt%, Mo: 3wt%, C: 0.1wt%, Nb: 2wt%, Y: 0.02wt%, B: 0.02wt%, balance Ni. This part has localized penetrating crack defects, such as... Figure 3 As shown, the depth of the crack defect is 10 mm.

[0125] It should be noted that the chemical composition of the solder powder used in this embodiment is as follows:

[0126] Cr: 13wt%, W: 6.5wt%, B: 3wt%, balance Ni.

[0127] The solder powder used in this embodiment has a particle size of -150 mesh.

[0128] The chemical composition of the filler powder used in this embodiment is as follows:

[0129] Cr: 9wt%, Co: 5wt%, Al: 6wt%, W: 3.5wt%, Mo: 3wt%, C: 0.1wt%, Nb: 2wt%, Y: 0.02wt%, B: 0.02wt%, balance Ni. The chemical composition is the same as that of high-temperature alloy parts. The filler powder particle size is -100 mesh.

[0130] In addition, the ingredients of the first paste are as follows: filler powder and solder powder are uniformly mixed in a ratio of 2:8 to form a first mixed powder, and the first mixed powder is uniformly mixed with NICROBRAZ S-BINDER adhesive in a weight ratio of 9:1 to form the first paste.

[0131] The second paste is formulated as follows: filler powder and solder powder are uniformly mixed in a 5:5 ratio to form a second mixed powder. The second mixed powder is then uniformly mixed with NICROBRAZ S-BINDER adhesive in a 10:1 weight ratio to form the second paste.

[0132] The method in this embodiment mainly includes the following steps:

[0133] Cleaning steps for the area to be welded: After mechanically grinding the defective areas of the high-temperature alloy parts, clean them with anhydrous ethanol.

[0134] Step 1: Fill the defect area with the first paste and compact it. The filling degree should be slightly higher than the original surface of the defective part. Allow it to dry naturally.

[0135] Steps for filling with the second paste: After removing the solder that extends beyond the outer surface prototype of the defect on both sides of the part, continue to remove 25% of the solder inside the part to be soldered from both sides of the part to be repaired (with an error controlled within ±5%); fill the cleaned part with the second paste and compact it, ensuring the filling degree is slightly higher than the outer surface prototype of the part, and allow it to dry naturally.

[0136] Step 1: Remove any solder that extends beyond the prototype surfaces on both sides of the part; apply the first solder paste to both sides of the defect to be repaired, with a total application amount of 3 times the volume of the area to be soldered, and allow it to air dry; apply a flow-blocking agent around the solder and allow it to air dry.

[0137] Vacuum brazing steps: Place the parts in a vacuum furnace, evacuate to a vacuum pressure not exceeding 0.04 Pa, heat the furnace to 1210°C at a rate of 6°C / min, hold for 240 min, and after holding, cool the furnace to below 100°C before removing from the furnace.

[0138] Surface treatment steps: The excess brazing filler metal on the outer surface of the repair area is piled up and polished to the original surface state, and the part is sandblasted with 140-mesh corundum sand at a pressure of 0.4MPa.

[0139] In this embodiment, the large-sized penetrating crack defect of the part was successfully repaired. The repaired area showed no unwelded defects and no brazing filler metal flowed into non-welded areas. Figure 4 As shown.

[0140] Example 4

[0141] This embodiment describes gap brazing of a high-temperature alloy component, wherein the high-temperature alloy component is a single-crystal high-temperature alloy turbine blade cast in a directional single-crystal furnace, and its chemical composition is as follows:

[0142] Cr: 3.2 wt%, Co: 6.4 wt%, W: 7.5 wt%, Ta: 6.7 wt%, Al: 5.8 wt%, Mo: 1.4 wt%, Re: 4.2 wt%, Nb: 0.45 wt%, balance Ni.

[0143] The blade tip cover plate hole of this high-temperature alloy part needs to be sealed by brazing. The cover plate hole is a gap with a diameter of 2.2mm. The sealing of a hole of this size is a large gap brazing.

[0144] The chemical composition of the solder used in this embodiment is as follows:

[0145] Cr: 13wt%, Co: 6wt%, W: 4wt%, B: 1.25wt%, Al: 3.8wt%, Mo: 1.4wt%, balance Ni.

[0146] The solder particle size is -150 mesh.

[0147] The chemical composition of the filler powder used in this embodiment is as follows:

[0148] Cr: 8.4 wt%, Co: 9.5 wt%, W: 9.6 wt%, Ta: 2.9 wt%, Al: 5.4 wt%, Mo: 0.6 wt%, Ti: 0.8 wt%, C: 0.07 wt%, B: 0.01 wt%, Zr: 0.01 wt%, Hf: 1.3 wt%, balance Ni. The chemical composition of this filler powder differs from that of the high-temperature alloy parts. The filler particle size is -100 mesh.

[0149] In addition, the ingredients of the first paste are as follows: filler powder and solder powder are uniformly mixed in a ratio of 2:8 to form a first mixed powder, and the first mixed powder is uniformly mixed with NICROBRAZ S-BINDER adhesive in a weight ratio of 11:1 to form the first paste.

[0150] The second paste is formulated as follows: filler powder and solder powder are uniformly mixed in a 4:6 ratio to form a second mixed powder. The second mixed powder is then uniformly mixed with NICROBRAZ S-BINDER adhesive in a 11:1 weight ratio to form the second paste.

[0151] The method in this embodiment mainly includes the following steps:

[0152] Cleaning steps for the area to be welded: After mechanically grinding the cover plate hole, clean the cover plate hole with anhydrous ethanol.

[0153] Step for filling the first paste: Use the first paste to fill the hole in the cover plate of the part and compact it. After filling, the outer surface of the cover plate will have a height higher than the prototype surface. Dry it at 80°C for 10 minutes.

[0154] Steps for filling with the second paste: After removing the solder from outside the cover plate of the part, continue to remove 50% of the solder from inside the hole of the cover plate (the error is controlled within ±10%); fill the area that has just been emptied with the second paste and compact it. After filling, there will be a residual height on the outer surface of the cover plate that is higher than the prototype surface. Dry it at 80°C for 5 minutes.

[0155] Steps for applying the first paste: Remove any solder that extends beyond the cover plate of the component; apply the first paste to the surface of the cover plate hole, with an application amount twice the volume of the cover plate hole, and dry at 80°C for 5 minutes; apply a flow retardant around the solder and dry at 80°C for 10 minutes.

[0156] Vacuum brazing steps: Place the parts in a vacuum furnace, evacuate to a vacuum pressure not exceeding 0.04 Pa, heat the furnace to 1080°C at a rate of 10°C / min, hold for 20 min (this is an additional holding step added during the heating stage), then heat to 1250°C at a rate of 13°C / min, hold for 30 min, after the holding is completed, cool the furnace to below 1000°C, then purge with argon gas and cool to below 100°C before removing from the furnace;

[0157] Surface treatment steps: Keep the brazing filler metal piled up at the cover plate hole, do not polish or sandblast.

[0158] In this embodiment, the cover plate hole of the part was successfully sealed and welded, the hole was fully filled, there were no unwelded defects, and there was no overflow in the non-welded area of ​​the inner cavity. A high-quality brazing connection was successfully achieved for the 2.2mm gap.

[0159] Example 5

[0160] This embodiment involves gap brazing of a stainless steel component, which is a 1Cr11Ni2W2MoV heat-resistant stainless steel blade assembly formed by free forging after being smelted in an electric arc furnace. Its chemical composition is as follows:

[0161] Ni: 1.6wt%, Cr: 11wt%, W: 1.7wt%, Mo: 0.4wt%, V: 0.22wt%, C: 0.12wt%, Fe is the balance.

[0162] The brazing gap of this stainless steel blade assembly is 0.8 mm, which is considered a large gap brazing. Figure 5 The image shown is of the gap.

[0163] The chemical composition of the solder used in this embodiment is as follows: Cr: 13wt%, W: 3wt%, B: 4.5wt%, Si: 2.8wt%, Ni as the balance. The particle size of the solder is -150 mesh.

[0164] The filler powder used in this embodiment is FGH4095, and its chemical composition is as follows:

[0165] Cr: 13wt%, Co: 7.5wt%, W: 3.5wt%, Mo: 3.5wt%, Al: 3.5wt%, Ti: 2.5wt%, Nb: 3.5wt%, B: 0.01wt%, Zr: 0.05wt%, balance Ni. The chemical composition of the filler powder differs from that of the stainless steel component.

[0166] The particle size of the filler powder is -100 mesh.

[0167] In addition, the ingredients of the first paste are as follows: filler powder and solder powder are uniformly mixed in a ratio of 2:8 to form a first mixed powder, and the first mixed powder is uniformly mixed with NICROBRAZ S-BINDER adhesive in a weight ratio of 9:1 to form the first paste.

[0168] The second paste is formulated as follows: filler powder and solder powder are uniformly mixed in a 6:4 ratio to form a second mixed powder. The second mixed powder is then uniformly mixed with NICROBRAZ S-BINDER adhesive in a 9:1 weight ratio to form the second paste.

[0169] The method in this embodiment mainly includes the following steps:

[0170] Cleaning steps for the area to be welded: Clean the area to be welded with anhydrous ethanol.

[0171] Step 1: Fill the gap to be welded with the first paste and compact it. After filling, there will be excess height outside the gap that is higher than the original surface. Allow it to dry naturally.

[0172] Step 2: After removing the solder that extends beyond the outer surface of the part, continue removing 50% of the solder inside the area to be soldered from the side closest to the outer surface (with an error within ±10%). Fill the voids in the area to be soldered with the second solder paste and compact it. The filling depth should not be less than that of the outer surface of the part. Allow it to dry naturally.

[0173] Step 1: Remove any solder that exceeds the prototype surface of the part's outer surface; apply the first solder paste to the outer surface of the area to be soldered, with an application amount equal to 2.5 times the volume of the gap to be soldered, and allow it to air dry; apply a flow-blocking agent around the solder and allow it to air dry.

[0174] Vacuum brazing procedure: Place the parts in a vacuum furnace, evacuate to a vacuum pressure not exceeding 0.04 Pa, heat the furnace to 1040°C at a rate of 10°C / min, and hold at 1040°C for 10 minutes. After holding, cool the furnace to 500°C, then purge with argon gas and cool to below 100°C before removing from the furnace. Retain all brazing leads; do not grind or blow sand.

[0175] Figure 6The image shows the original gap after brazing the stainless steel parts in Example 5. It can be seen that this example successfully completed the large gap brazing of the 1Cr11Ni2W2MoV heat-resistant stainless steel blade assembly, with no unwelded defects and no brazing filler metal flowing into the non-welded area. It successfully achieved a high-quality brazing connection for the 0.8mm gap.

[0176] Example 6

[0177] This embodiment repairs crack defects. The high-temperature alloy part is a fuel nozzle manufactured using laser selective melting additive manufacturing technology, and its chemical composition is as follows:

[0178] Cr: 8wt%, Co: 8wt%, W: 8wt%, Al: 5.5wt%, Ti: 0.8wt%, Mo: 2wt%, C: 0.1wt%, Ta: 6wt%, B: 0.01wt%, Ni is the balance. The part surface has non-penetrating cracks with a depth of 1mm.

[0179] The chemical composition of the solder used in this embodiment is as follows: Cr: 14.8 wt%, W: 6.9 wt%, B: 3.1 wt%, Ni as the balance. The particle size of the solder is -150 mesh.

[0180] The chemical composition of the filler powder used in this embodiment is as follows: Cr: 8wt%, Co: 8wt%, W: 8wt%, Al: 5.5wt%, Ti: 0.8wt%, Mo: 2wt%, C: 0.1wt%, Ta: 6wt%, B: 0.01wt%, Ni as the balance. The composition of the filler powder is the same as that of the high-temperature alloy parts; the particle size of the filler powder is -100 mesh.

[0181] In addition, the ingredients of the first paste are as follows: filler powder and solder powder are uniformly mixed in a ratio of 2:8 to form a first mixed powder, and the first mixed powder is uniformly mixed with NICROBRAZ S-BINDER adhesive in a weight ratio of 10:1 to form the first paste.

[0182] The second paste is formulated as follows: filler powder and solder powder are uniformly mixed in a 5:5 ratio to form a second mixed powder. The second mixed powder is then uniformly mixed with NICROBRAZ S-BINDER adhesive in a 10:1 weight ratio to form the second paste.

[0183] The method in this embodiment mainly includes the following steps:

[0184] Cleaning steps for the parts to be soldered: Clean the parts to be soldered with acetone.

[0185] Step 1: Fill the defect area to be repaired with the first paste and compact it. The filling degree should be slightly higher than the original surface of the defect. Dry at 100°C for 20 minutes.

[0186] Steps for filling with the second paste: After removing the solder that extends beyond the outer surface of the part, continue to remove 50% of the solder inside the defect from the side closest to the outer surface (with the error controlled within ±10%); fill the cleared area with the second paste and compact it, ensuring the filling degree is slightly higher than the outer surface of the part, and dry it at 100°C for 10 minutes.

[0187] First paste application step: Remove any solder that extends beyond the prototype surface of the part's outer surface. Apply the first paste to the outer surface of the defect to be repaired, using an amount twice the volume of the area to be soldered, and dry at 100°C for 10 minutes. Apply a flow-retardant around the solder and dry at 100°C for 10 minutes.

[0188] Vacuum brazing steps: Place the parts in a vacuum furnace, evacuate to a vacuum pressure not exceeding 0.04 Pa, heat the furnace to 1190°C at a rate of 4°C / min, and hold at 1190°C for 100 min. After holding, cool the parts with the furnace to below 100°C and remove them from the furnace.

[0189] Surface treatment: The excess brazing filler metal on the outer surface of the repaired part is piled up and polished to the original surface state, and the part is sandblasted with 140-mesh corundum sand at a pressure of 0.4MPa.

[0190] In this embodiment, the large-sized non-penetrating crack defect of the part was successfully repaired, and the repaired area had no unwelded defects and no brazing filler metal flowed into the non-welded area.

[0191] Example 7

[0192] This embodiment describes the repair of crack defects in a high-temperature alloy component. The high-temperature alloy component in this embodiment is a K417G low-vortex guide vane, cast in a vacuum precision casting furnace, with the following chemical composition:

[0193] The composition is as follows: Cr: 9wt%, Co: 10wt%, Al: 5.3wt%, Ti: 4.5%, Zr: 0.07wt%, Mo: 3.3wt%, C: 0.2wt%, V: 0.7wt%, B: 0.02wt%, with the balance being Ni. The part has a localized penetrating crack with a depth of 1.8mm.

[0194] It should be noted that the chemical composition of the solder powder used in this embodiment is as follows: Cr: 13wt%, W: 6.5wt%, B: 3wt%, with the balance being Ni.

[0195] The solder powder used in this embodiment has a particle size of -150 mesh.

[0196] The chemical composition of the filler powder used in this embodiment is as follows:

[0197] Cr: 9wt%, Co: 10wt%, Al: 5.3wt%, Ti: 4.5%, Zr: 0.07wt%, Mo: 3.3wt%, C: 0.2wt%, V: 0.7wt%, B: 0.02wt%, balance Ni. The chemical composition is the same as that of high-temperature alloy parts. The filler powder particle size is -100 mesh.

[0198] In addition, the ingredients of the first paste are as follows: filler powder and solder powder are uniformly mixed in a ratio of 2:8 to form a first mixed powder, and the first mixed powder is uniformly mixed with NICROBRAZ S-BINDER adhesive in a weight ratio of 9:1 to form the first paste.

[0199] The second paste is formulated as follows: filler powder and solder powder are uniformly mixed in a 5:5 ratio to form a second mixed powder. The second mixed powder is then uniformly mixed with NICROBRAZ S-BINDER adhesive in a 10:1 weight ratio to form the second paste.

[0200] The method in this embodiment mainly includes the following steps:

[0201] Cleaning steps for the area to be welded: After mechanically grinding the defective areas of the high-temperature alloy parts, clean them with anhydrous ethanol.

[0202] Step 1: Fill the defect area with the first paste and compact it. The filling degree should be slightly higher than the original surface of the defective part. Allow it to dry naturally.

[0203] Steps for filling with the second paste: After removing the solder that extends beyond the outer surface prototype of the defect on both sides of the part, continue to remove 25% of the solder inside the part to be soldered from both sides of the part to be repaired (with an error controlled within ±5%); fill the cleaned part with the second paste and compact it, ensuring the filling degree is slightly higher than the outer surface prototype of the part, and allow it to dry naturally.

[0204] Step 1: Remove any solder that extends beyond the prototype surfaces on both sides of the part; apply the first solder paste to both sides of the defect to be repaired, with a total application amount of 3 times the volume of the area to be soldered, and allow it to air dry; apply a flow-blocking agent around the solder and allow it to air dry.

[0205] Vacuum brazing steps: Place the parts in a vacuum furnace, evacuate to a vacuum pressure not exceeding 0.04 Pa, heat the furnace to 1150°C at a rate of 6°C / min, hold for 30 minutes, and after holding, cool the furnace to below 100°C before removing it from the furnace.

[0206] Surface treatment steps: The excess brazing filler metal on the outer surface of the repair area is piled up and polished to the original surface state, and the part is sandblasted with 140-mesh corundum sand at a pressure of 0.4MPa.

[0207] In this embodiment, the large-sized penetrating crack defect of the part was successfully repaired. The repaired area had no unwelded defects and no brazing filler metal flowed into the non-welded areas. Figure 7 and Figure 8 The image shows the microstructure of the repaired area. It is evident that the interface between the brazed weld seam and the base material is not straight. This is because the gaps within the original crack defect are deep and vary in width. Furthermore, during the dissolution and resolidification of the base material, the filler metal is affected by the different diffusion rates of grain boundaries and dendrites in the base material, further exacerbating the interface distortion and resulting in a wavy final interface between the brazed weld seam and the base material. Figure 7 The two dashed lines in the diagram only represent the approximate interface of this region, showing the average width of the brazing seam in a flat manner. From Figure 7 and Figure 8 It is known that the brazed joint matrix is ​​a γ-Ni solid solution rich in γ′ precipitate phase, with high-melting-point skeletal, massive, and granular borides distributed throughout, and no low-melting-point eutectic structure. The filler powder with suitable particle size and composition provides sufficient γ-Ni matrix and γ′ reinforcing phase forming elements, and plays a sufficient supporting role. Combined with small-particle solder powder rich in elements such as Cr and W, during the joining process, the interdiffusion between the solder and filler allows the molten solder in the repaired area to acquire more precipitation strengthening and solid solution strengthening elements. While ensuring sufficient fluidity and wettability, the brazed joint achieves a matrix structure similar to the base material, rich in high-temperature strengthening phases, and avoids the formation of low-melting-point eutectic structures. Its excellent joint microstructure ensures the high-temperature service performance of the repaired part.

[0208] Comparative Example 1

[0209] Comparative Example 1 involves sealing the hole in the blade tip cover plate of a component using brazing. The difference from Example 1 is that the composition of the second paste is the same as that of the first paste, specifically as follows:

[0210] The ingredients of the first paste are as follows: filler powder and solder powder are uniformly mixed in a mass ratio of 3:7 to form the first mixed powder, and the first mixed powder is uniformly mixed with NICROBRAZ S-BINDER adhesive in a mass ratio of 11:1 to form the first paste.

[0211] The second paste is formulated as follows: filler powder and solder powder are uniformly mixed in a mass ratio of 3:7 to form a second mixed powder. The second mixed powder is then uniformly mixed with NICROBRAZ S-BINDER adhesive in a mass ratio of 11:1 to form the second paste.

[0212] Everything else is completely consistent with Example 1.

[0213] Figure 9 The image shown is a photograph of the brazed area after the sealing brazing in Comparative Example 1. It was found that the area to be brazed was not properly welded, and the brazing filler metal, under gravity, flowed into the inner cavity of the non-welded area below, spreading along the inner cavity and flowing to the outside of the part through the vent holes (see [reference]). Figure 10 (As shown).

[0214] As can be seen, Comparative Example 1 failed to achieve brazing, which indicates that if the ratio of filler powder and solder powder does not meet the requirements of this invention, large-gap brazing cannot be achieved, and the welded part will have defects of not being welded.

[0215] Comparative Example 2

[0216] Comparative Example 2 repairs crack defects in a high-temperature alloy part. The only difference between Comparative Example 2 and Example 2 is that the chemical composition of the solder used in Comparative Example 2 is as follows:

[0217] Co: 8wt%, Cr: 5wt%, W: 9wt%, B: 3wt%, Mo: 2wt%, Al: 4.5wt%, Ti: 1wt%, Si: 3wt%, Ta: 7wt%, balance Ni.

[0218] Everything else is completely consistent with Example 2.

[0219] In Comparative Example 2, after crack repair, inspection revealed that a large, non-penetrating crack on the part still had a localized area of ​​incomplete welding, measuring 2 mm in length and 0.3 mm in depth. The repair was unsuccessful because the excessively high levels of W and Ta in the solder reduced its fluidity and wettability, resulting in insufficient shrinkage of the repaired area and subsequent incomplete welding. This demonstrates that if the composition of the solder powder does not meet the requirements of this invention, large-size defects cannot be repaired, and incomplete welding will occur at the welded area.

[0220] Comparative Example 3

[0221] Comparative Example 3 repaired crack defects in a high-temperature alloy part. The difference between Comparative Example 3 and Example 3 is that:

[0222] The only difference between this comparative example and Example 3 is that, in the vacuum brazing step, the temperature is raised to 1270°C and held at that temperature.

[0223] Everything else is completely consistent with Example 2.

[0224] Figure 11 The image shown is a photograph of the repaired area in Comparative Example 3 after defect repair. Inspection revealed that the large penetrating crack defect in the part could not be successfully repaired. This was due to excessively high brazing temperature causing overheating of the brazing filler metal, resulting in brazing filler metal loss at the original crack site, leading to an unwelded defect 65mm long and 2mm deep. This illustrates that if the brazing temperature does not meet the requirements of this invention, large-sized defects cannot be repaired, and the welded area will exhibit an unwelded defect.

[0225] Comparative Example 4

[0226] Comparative Example 4 involved gap brazing of a high-temperature alloy component. The difference between Comparative Example 4 and Example 4 was that the particle size of the solder was -100 mesh and the particle size of the filler was -150 mesh.

[0227] Everything else is the same as in Example 4.

[0228] In Comparative Example 4, after gap brazing, inspection revealed that the brazing filler metal had overflowed into the inner cavity, with a maximum overflow distance of 2 mm and a maximum thickness of 0.5 mm, indicating that brazing was unsuccessful. The solder particle size in Comparative Example 4 was too large, while the filler particle size was too small. This caused the molten solder to excessively dissolve the filler during brazing, resulting in the filler losing its supporting framework function and causing the brazing filler metal to overflow. This demonstrates that if the particle size of the solder and filler does not meet the requirements of this invention, large-gap brazing cannot be achieved, and incomplete welding defects will appear at the welded areas.

[0229] Comparative Example 5

[0230] Comparative Example 5 involved gap brazing of stainless steel parts. The only difference between Comparative Example 5 and Example 5 was that, in preparing the first paste, the mass ratio of the first mixed powder to the adhesive was 7:1. Similarly, in preparing the second paste, the mass ratio of the second mixed powder to the adhesive was 7:1.

[0231] Everything else is the same as in Example 5.

[0232] In Comparative Example 5, post-weld inspection revealed a long, strip-shaped incomplete weld defect extending 7 mm in length and 0.8 mm in depth along the weld seam. This indicated that large-gap brazing was unsuccessful. The low powder content in the brazing paste resulted in insufficient solids to ensure even distribution across the weldable area. Furthermore, the excessive binder in the paste evaporated during heating, causing collapse and leading to the large defect after brazing. This demonstrates that if the powder-to-binder ratio does not meet the requirements of this invention, large-gap brazing cannot be achieved, and incomplete weld defects will appear at the welded area.

[0233] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for brazing gaps or repairing defects in metal parts, characterized in that, It includes the following steps: Step of filling the first paste: Fill the part to be welded of the metal part with the first paste, so that the first paste fills the part to be welded and compacts it, and then performs a drying treatment; wherein, the part to be welded is a gap or defect; wherein, the first paste is prepared by a first mixed powder and an adhesive; wherein, the first mixed powder includes filler powder and solder powder in a mass ratio of 2:8-3:

7. Partial removal of the first paste step: Remove part of the first paste that is filled in the area to be soldered to create a void in the area to be soldered; The second paste filling step involves filling the gaps in the area to be soldered with the second paste, compacting it, and then drying it. The second paste is prepared from a second mixed powder and an adhesive. The second mixed powder comprises filler powder and solder powder in a mass ratio of 4:6 to 6:

4. First paste covering step: Cover the outer surface of the metal part to be welded after the second paste filling step with the first paste, dry it, apply a flow barrier around the paste, and dry it to obtain the metal part after the first paste covering step. Vacuum brazing step: Vacuum brazing is performed on the metal parts after the first paste covering step to obtain metal parts with gap brazing or defect repair.

2. The method for brazing gaps or repairing defects in metal parts according to claim 1, characterized in that, The metal part is a high-temperature alloy part or a stainless steel part; and / or If the area to be welded is a gap requiring brazing, the maximum diameter or width of the gap is 2.5 mm; and / or If the area to be welded is defective, the maximum depth of the defect is 10mm.

3. The method for gap brazing or defect repair of metal parts according to claim 1 or 2, characterized in that, The chemical composition of the solder, by weight fraction, is as follows: Cr: 7-15wt%, W: 3-8wt%, B: 0.9-4.5wt%, Si: 0-3wt%, Co: 0-10wt%, Al: 0-4.5wt%, Ta: 0-6wt%, Mo: 0-4.5wt%, Ti: 0-5wt%, balance Ni; When the metal part contains a first element, wherein the first element is any one of Co, Al, Ta, Mo, and Ti: the content of the first element in the solder does not exceed the content of the first element in the metal part. When the metal part does not contain the first element, wherein the first element is any one of Co, Al, Ta, Mo, and Ti: the first element is not added to the solder.

4. The method for brazing gaps or repairing defects in metal parts according to claim 1 or 2, characterized in that, The solder powder has a particle size of -150 mesh; and / or The filler powder has a particle size of -100 mesh; and / or The chemical composition of the filler powder may be the same as or different from that of the metal part; and / or In the first paste, the mass ratio of the first mixed powder to the adhesive is 9:1-12:1; and / or In the second paste, the mass ratio of the second mixed powder to the adhesive is 9:1 to 12:

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5. The method for gap brazing or defect repair of metal parts according to claim 1 or 2, characterized in that, Prior to the step of filling the first paste, the method further includes: Cleaning steps for the area to be welded: Use anhydrous ethanol or acetone to clean the area of ​​the metal part to be welded that needs gap brazing or defect repair. If there is a layer of dirt on the part to be soldered, remove the dirt first by surface treatment, and then clean the part to be soldered.

6. The method for gap brazing or defect repair of metal parts according to claim 1 or 2, characterized in that, In the step of filling the first paste: The first paste must fill the area to be soldered to the required extent that: the first paste completely fills the area to be soldered and extends beyond the original surface of the metal part; and / or The drying process is carried out by either natural drying or oven drying.

7. The method for gap brazing or defect repair of metal parts according to claim 1 or 2, characterized in that, In the step of removing part of the first paste: Remove the first paste that extends above the prototype surface from the metal part after the first paste filling step; then remove the portion of the first paste that was filled in the area to be welded to form a gap in the area to be welded. and / or The volume of the gap occupies 40-60% of the volume of the area to be welded; and / or If one side of the part to be welded is an opening, remove part of the first paste from the opening; if the part to be welded is a penetrating gap or defect, remove part of the first paste from one or both openings of the part to be welded.

8. The method for gap brazing or defect repair of metal parts according to claim 1 or 2, characterized in that, In the step of filling the second paste: the filling degree of the second paste at the area to be soldered must meet the following requirements: the second paste fills the gaps in the area to be soldered and extends beyond the prototype surface of the metal part; and / or In the step of covering the first paste: after removing the second paste that extends beyond the prototype surface from the metal part treated in the step of filling the second paste, the first paste is applied to the outer surface of the area to be soldered; and / or In the step of covering the first paste: the volume of the first paste covering the outer surface of the part to be soldered is not less than twice the volume of the part to be soldered.

9. The method for gap brazing or defect repair of metal parts according to claim 1 or 2, characterized in that, In the vacuum brazing step: The metal parts treated with the first paste are placed in a vacuum furnace, and the vacuum pressure is evacuated to no higher than 0.04 Pa. The metal parts are heated to 1040-1260°C at a heating rate of no higher than 15°C / min, and held at 1040-1260°C for 10-240 min. After the holding time is completed, the parts are cooled to obtain metal parts with gap brazing or defect repair. If the vacuum pressure exceeds 0.04 Pa during the heating process, the heating should be paused and resumed when the vacuum pressure drops below 0.04 Pa.

10. The method for brazing gaps or repairing defects in metal parts according to claim 1 or 2, characterized in that, Following the vacuum brazing step, a surface treatment step is also included: polishing the excess brazing filler metal on the outer surface of the metal part after gap brazing or defect repair to a prototype surface state; or retaining part or all of the brazing filler metal buildup or brazing leads as required; and / or The welded parts of the metal parts after gap brazing or defect repair have no unwelded defects, and the brazing matrix is ​​a γ-Ni solid solution rich in γ′ precipitate phase, with borides distributed and no eutectic structure; wherein the shape of the borides includes skeleton-like, blocky, and granular.

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