HPb59-1 high-zinc lead brass laser brazing additive repairing method and application

Abstract

The invention discloses an HPb59-1 high-zinc lead brass laser brazing additive repairing method and application, and belongs to the technical field of high-zinc lead brass brazing additive. According to the method, the laser brazing additive repairing technology is applied to airplane HPb59-1 high-zinc lead brass damage repairing, the problems that due to conventional fusion welding repairing, Pb and Zn elements in HPb59-1 alloy are evaporated, human health is harmed, the mechanical property of a welded joint is reduced, and the airplane HPb59-1 high-zinc lead brass part damage repairing quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of high-zinc-lead brass brazing additive technology, and more specifically to a HPb59-1 high-zinc-lead brass laser brazing additive repair method and application. Background Art

[0002] HPb59-1 alloy is a medium-lead (α+β) two-phase brass, which belongs to high-zinc brass. The alloy has high strength, excellent machinability and formability, is suitable for hot processing, and has a strong tendency to stress corrosion damage. Cold-work hardened materials and parts should be subjected to stress relief low-temperature annealing. Its tensile strength is between 392MPa-480MPa. It is a non-heat-treated strengthened copper alloy and is mainly used in the manufacture of aircraft gears, bushings and other parts. However, during the long-term service of aircraft, HPb59-1 alloy parts are worn, affecting the performance of parts and endangering flight safety.

[0003] Repairs by replacing them with new ones are costly and often hinder the repair progress due to difficulties in supplying spare parts, affecting production.

[0004] At present, the thread damage of HPb59-1 alloy electrical column is usually repaired by fusion welding. However, the melting point of HPb59-1 alloy is between 886℃-901℃. The mass fractions of the chemical elements in the alloy are: Pb0.8%-1.9%, Zn38%-42%, Cubal, among which the melting point of Pb is 327.5℃. Lead is also a toxic heavy metal, which is harmful to the human body, especially at high temperatures, it will release toxic lead vapor. The melting point of Zn is 419.53C. The fusion welding process causes the Pb and Zn elements in the alloy to evaporate, which not only harms human health, but also reduces the mechanical properties of the welded joint.

[0005] Based on this, the present invention provides an additive repair process for the problem of damage repair of aircraft HPb59-1 composite parts, which effectively improves the quality of additive repair of aircraft HPb59-1 composite parts. Summary of the invention

[0006] In view of this, the present invention provides a HPb59-1 high zinc-lead brass laser brazing additive repair method and application, which effectively improves the additive repair quality of aircraft HPb59-1 composite parts.

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

[0008] A laser brazing additive repair method for HPb59-1 high zinc-lead brass comprises the following steps:

[0009] (1) Using DSC differential scanning calorimeter to measure the melting point of the prepared solder powder;

[0010] (2) Clean the area to be repaired. Laser clean the end surface of the area to be repaired to remove the oxide layer, ensure that the metal luster is exposed, the surface is clean, and then clean it with acetone;

[0011] (3) The defects are confirmed to be eliminated through non-destructive testing, and a protective layer is applied to other parts of the parts that may be irradiated by the laser except the repaired area;

[0012] (4) Evenly mix the flux 101 and the solder powder, and place the mixed powder in a powder feeding bucket in a powder feeder;

[0013] (5) Carry out optimization of laser brazing process parameters to ensure that the temperature of the laser temperature field during laser brazing is between 809°C and 829°C. The temperature of the laser temperature field is detected online using an online infrared thermometer;

[0014] (6) During the process of laser brazing additive repair and shape control, the interlayer temperature is strictly controlled. When the interlayer temperature drops below 40°C, the next layer is repaired by laser additive. The interlayer temperature is detected by an infrared thermometer.

[0015] (7) After one layer is repaired during laser brazing additive repair, laser cleaning is used to clean the surface of the additive repair layer to remove the oxide layer, ensure that the metal luster is exposed, the surface is clean and cleaned with acetone, and then the next layer is repaired and steps (6) to (7) are repeated;

[0016] (8) After the repair is completed, it is machined into standard size;

[0017] (9) After machining, it can be put into use if no cracks are found using fluorescent testing.

[0018] Preferably, the solder powder composition includes: Ag 53.5-54.5wt%; Cu 45.5-46.5wt%, and its melting range is 760°C-810°C.

[0019] Preferably, the sphericity of the solder powder is ≥0.9.

[0020] Preferably, the particle size of the solder powder is 45 μm-105 μm, and particles <45 μm account for ≤5%, and particles >105 μm account for ≤5%.

[0021] Preferably, the solder powder is prepared by a plasma rotating electrode method.

[0022] Preferably, the volume ratio of the flux 101 to the solder powder is 1:2.

[0023] Preferably, the flux 101 is a mixture of potassium fluoroborate and boric acid in a mass ratio of (68-71):(32-29).

[0024] Preferably, the laser brazing process parameters are:

[0025] Powder feeding gas: 99.999% high purity argon;

[0026] Laser brazing alloy powder uses silver-based brazing powder;

[0027] Laser power: 900-1300W;

[0028] Scanning speed: 8-10mm / s;

[0029] Spot diameter: 2mm;

[0030] Powder feeder speed: 0.8-1r / min;

[0031] Powder feeding gas flow rate: 4-6L / min;

[0032] Protective gas flow rate: 18-20L / min;

[0033] Overlap rate: 40%-50%.

[0034] Another object of the present invention is to provide an application of the above-mentioned HPb59-1 high zinc-lead brass laser brazing additive repair method in aircraft HPb59-1 high zinc-lead brass damage repair.

[0035] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention applies laser brazing additive repair technology to the damage repair of aircraft HPb59-1 high-zinc-lead brass, which solves the problem of evaporation of Pb and Zn elements in the HPb59-1 alloy caused by conventional fusion welding repair, which not only harms human health but also reduces the mechanical properties of the welded joint, thereby improving the damage repair quality of aircraft HPb59-1 high-zinc-lead brass parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0038] Figure 1 It is a process flow chart of the present invention.

[0039] Figure 2 This is the metallographic diagram of the optimal silver-based solder brazing.

[0040] Figure 3This is the brazing metallographic diagram of the silver-based solder ratio No. 1.

[0041] Figure 4 This is the brazing metallographic diagram of the No. 2 silver-based solder ratio.

[0042] Figure 5 This is the brazing metallographic diagram of base solder ratio No. 3.

[0043] Figure 6 This is the brazing metallographic diagram of base solder ratio No. 4. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] This embodiment provides a laser brazing additive repair method for HPb59-1 high zinc-lead brass, wherein the brazing alloy powder has the following specific components: Ag53.5%, Cu46.5%.

[0047] Solder alloy powder sphericity: ≥0.9;

[0048] The particle size range of solder alloy powder is: 45μm-105μm, of which <45μm accounts for ≤5%, and >105μm accounts for ≤5%.

[0049] The solder alloy powder was prepared by plasma rotating electrode method.

[0050] The flux 101 is a mixture of potassium fluoroborate and boric acid, with a mass ratio of 70:30.

[0051] The particle size of the flux 101 powder is ≤105μm.

[0052] Laser brazing, its specific process parameters are:

[0053] Powder feeding gas: 99.999% high purity argon;

[0054] Laser power: 1000W;

[0055] Scanning speed: 10mm / s;

[0056] Spot diameter: 2mm

[0057] Powder feeder speed 0.9r / min;

[0058] Powder feeding gas flow rate: 5L / min;

[0059] Protective gas flow rate: 20L / min;

[0060] Overlap rate: 50%.

[0061] The specific steps include:

[0062] (1) The melting point of the prepared solder powder measured by DSC differential scanning calorimeter is 779℃;

[0063] (2) Cleaning of the area to be repaired. The end surface of the area to be repaired is cleaned with laser to remove the oxide layer, ensuring that the metallic luster is exposed and the surface is clean and then cleaned with acetone.

[0064] (3) Defect elimination needs to be confirmed by non-destructive testing. Use aluminum foil to protect other parts of the parts that may be irradiated by the laser except the repair area to prevent laser irradiation from damaging the matrix of other parts during the repair process.

[0065] (4) The flux 101 and the solder powder are mixed evenly in a volume ratio of 1 part of flux 101 powder to 2 parts of solder powder, and the mixed powder is placed in a powder feeding bucket in a powder feeder.

[0066] (5) Carry out optimization of laser brazing process parameters to ensure that the temperature of the laser temperature field during laser brazing is between 809°C and 829°C. The temperature of the laser temperature field is detected online using an online infrared thermometer;

[0067] (6) The interlayer temperature should be strictly controlled during the process of laser brazing additive repair. When the interlayer temperature drops below 40 °C, the next layer can be repaired by laser additive. The interlayer temperature is detected by an infrared thermometer.

[0068] (7) During the laser brazing additive repair process, after repairing one layer, the surface of the additive repair layer is cleaned by blasting to remove the oxide layer, ensuring that the metal luster is exposed, the surface is clean and cleaned with acetone, and then the next layer is repaired and steps (6) to (7) are repeated.

[0069] (8) After the repair is completed, it is machined into standard size;

[0070] (9) After machining, it can be put into use if no cracks are found using fluorescent testing.

[0071] Mechanical properties verification

[0072] At the same time, according to the working conditions of high zinc-lead brass aircraft parts made of HPb59-1 alloy in the aviation maintenance field, it can be known that the material-level test shows that the bonding performance between the repair layer and the substrate is not less than 80% of the tensile strength of the substrate to meet the use requirements. The material-level test shows that the tensile strength after laser brazing is 325MPa, which meets the use requirements.

[0073] Some parameters of the present invention were modified as a comparative example, see Table 1 for details:

[0074] Table 1

[0075]

[0076] The present invention adopts brazing to repair the damage of the HPb59-1 alloy parts, so as to avoid the evaporation of Pb and Zn elements in the HPb59-1 alloy caused by fusion welding repair, which not only harms human health but also reduces the mechanical properties of the welded joint.

[0077] In the prior art, fusion welding repair is performed at a temperature higher than the melting point of the substrate, which causes evaporation of Pb and Zn elements, reduces the strengthening effect, and has a tensile strength lower than 280 MPa. The present invention uses laser brazing to ensure welding repair at a temperature lower than the melting point of the substrate, and has a tensile strength higher than 320 MPa.

[0078] The present invention adopts laser as heat source for brazing, thereby ensuring small brazing deformation and improving repair quality.

[0079] The specific parameters of laser brazing are obtained through process optimization; compared with oxyacetylene flame heat source and arc heat source, laser brazing has less deformation.

[0080] The present invention mixes the brazing agent 101 and the brazing material powder evenly in a volume ratio of 1 part of the brazing agent 101 powder to 2 parts of the brazing material powder, which can effectively remove the oxide film generated during the brazing process due to poor protection of coaxially transported high-purity argon and improve the brazing quality.

[0081] Laser brazing without flux 101 powder will only produce a partial oxide film under the protection of argon gas, and the brazing surface will be partially gray; laser brazing with flux 101 powder added will appear silvery white.

[0082] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0083] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laser brazing additive repair method for HPb59-1 high zinc-lead brass, characterized in that: The following steps are involved: (1) Using DSC differential scanning calorimeter to measure the melting point of the prepared solder powder; (2) Clean the area to be repaired. Laser clean the end surface of the area to be repaired to remove the oxide layer, ensure that the metal luster is exposed, the surface is clean, and then clean it with acetone; (3) The defects are confirmed to be eliminated through non-destructive testing, and a protective layer is applied to other parts of the parts that may be irradiated by the laser except the repaired area; (4) Evenly mix the flux 101 and the solder powder, and place the mixed powder in a powder feeding bucket in a powder feeder; (5) Carry out optimization of laser brazing process parameters to ensure that the temperature of the laser temperature field during laser brazing is between 809°C and 829°C. The temperature of the laser temperature field is detected online using an online infrared thermometer; (6) During the process of laser brazing additive repair and shape control, the interlayer temperature is strictly controlled. When the interlayer temperature drops below 40°C, the next layer is repaired by laser additive. The interlayer temperature is detected by an infrared thermometer. (7) After one layer is repaired during laser brazing additive repair, laser cleaning is used to clean the surface of the additive repair layer to remove the oxide layer, ensure that the metal luster is exposed, the surface is clean and cleaned with acetone, and then the next layer is repaired and steps (6) to (7) are repeated; (8) After the repair is completed, it is machined into standard size; (9) After machining, it can be put into use if no cracks are found using fluorescent testing.

2. The HPb59-1 high zinc-lead brass laser brazing additive repair method according to claim 1 is characterized in that: The solder powder comprises: 53.5-54.5wt% Ag; 45.5-46.5wt% Cu, and its melting range is 760°C-810°C.

3. The HPb59-1 high zinc-lead brass laser brazing additive repair method according to claim 2 is characterized in that: The sphericity of the solder powder is ≥0.

9.

4. The HPb59-1 high zinc-lead brass laser brazing additive repair method according to claim 3 is characterized in that: The particle size of the solder powder is 45 μm-105 μm, and the particle size of less than 45 μm is allowed to account for ≤5%, and the particle size of more than 105 μm is allowed to account for ≤5%.

5. The HPb59-1 high zinc-lead brass laser brazing additive repair method according to claim 1, characterized in that: The solder powder is prepared by a plasma rotating electrode method.

6. The HPb59-1 high zinc-lead brass laser brazing additive repair method according to claim 1, characterized in that: The volume ratio of the flux 101 to the solder powder is 1:

2.

7. A laser brazing additive repair method for HPb59-1 high zinc-lead brass according to claim 6, characterized in that: The brazing agent 101 is a mixture of potassium fluoroborate and boric acid in a mass ratio of (68-71):(32-29), wherein the powder particle size of the brazing agent 101 is ≤105 μm.

8. The HPb59-1 high zinc-lead brass laser brazing additive repair method according to claim 1, characterized in that: The laser brazing process parameters are: Powder feeding gas: 99.999% high purity argon; Laser brazing alloy powder uses silver-based brazing powder; Laser power: 900-1300W; Scanning speed: 8-10mm / s; Spot diameter: 2mm; Powder feeder speed: 0.8-1r / min; Powder feeding gas flow rate: 4-6L / min; Protective gas flow rate: 18-20L / min; Overlap rate: 40%-50%.

9. Application of the HPb59-1 high zinc-lead brass laser brazing additive repair method as described in any one of claims 1 to 8 in aircraft HPb59-1 high zinc-lead brass damage repair.

Images