A method for strengthening the nozzle wall of a titanium alloy muzzle brake

Abstract

The present invention belongs to the field of gun muzzle brake manufacturing, and relates to a method for strengthening the nozzle wall of a titanium alloy gun muzzle brake. The present invention adopts laser cladding technology to clad TiAl-based intermetallic compound powder on the nozzle wall of the titanium alloy gun muzzle brake to form a metallurgical bond with the titanium alloy matrix. The TiAl-based intermetallic compound powder selected by the present invention is grouped into the following groups according to volume percentage: Ti 2 AlNb alloy powder 40.0% - 50.0%, TiB 2 Ceramic particle powder 1.0% - 5.0%, the balance is TiAl alloy powder. 2 The addition of AlNb improves the overall plasticity of the material. 2 Ceramic particles further enhance the hardness and wear resistance of the coating. The titanium alloy gun muzzle brake prepared by the present invention has a coating thickness of no more than 0.5 mm, a substrate heat-affected zone thickness of 1 mm, and a cladding layer hardness of more than 700 HV, which significantly improves the hardness and wear resistance of the titanium alloy gun muzzle brake nozzle, and can significantly increase the service life of the titanium alloy gun muzzle brake.

Description

Technical Field

[0001] The invention belongs to the field of titanium alloy gun muzzle brake manufacturing and relates to a method for strengthening a spray hole of a titanium alloy gun muzzle brake. Background Art

[0002] During the firing process, the gun muzzle brake is subjected to multiple factors such as thermal shock, chemical ablation and mechanical wear. In the prior art, the gun muzzle brake parts are made of gun steel. Titanium alloy has the advantages of low density, high specific strength and good corrosion resistance. After replacing the steel gun muzzle brake with titanium alloy material, the same size replacement can achieve more than 40% weight reduction efficiency, and the application prospect is huge.

[0003] However, during the actual testing process, the nozzle wall of the titanium alloy artillery muzzle brake quickly showed erosion and ablation under the scouring of high-speed airflow, which caused the life of the titanium alloy muzzle brake to be seriously reduced. Therefore, there is an urgent need to improve the strength, ablation resistance and erosion resistance of the nozzle wall of the titanium alloy artillery muzzle brake at high temperatures.

[0004] Laser cladding technology can use high-energy laser beams to melt materials quickly, and after solidification, it forms a good metallurgical bond with the substrate, which can be used in areas such as material surface modification. This technology has the characteristics of dense cladding layer structure, fast forming, high degree of flexibility, and good controllability, so it can be used to enhance the performance of the nozzle wall of titanium alloy artillery recoil brake. Summary of the invention

[0005] The purpose of the present invention is to provide a method for strengthening the nozzle hole wall of a titanium alloy gun muzzle brake. The present invention selects TiAl-based intermetallic compound powder as the cladding material, adopts laser cladding technology to strengthen the nozzle hole wall of the titanium alloy gun muzzle brake, significantly improves the hardness and wear resistance of the nozzle hole wall, increases the service life of the titanium alloy gun muzzle brake, and breaks through the bottleneck of lightweight manufacturing of the gun muzzle brake.

[0006] In order to solve the above problems, the present invention adopts the following technical solutions:

[0007] A method for strengthening the nozzle wall of a titanium alloy muzzle brake, characterized in that it comprises the following steps:

[0008] Step 1: Clean and dry the titanium alloy artillery recoil brake;

[0009] Step 2: Place the TiAl-based intermetallic compound powder in a powder feeder of a laser cladding device, pass a protective gas in a closed forming tool, and the components of the TiAl-based intermetallic compound powder are composed by volume as follows: 40.0% to 50.0% Ti2AlNb alloy powder, 1.0% to 5.0% TiB2 ceramic particle powder, and the remainder is TiAl alloy powder;

[0010] Step 3, preheating the nozzle hole wall of the muzzle brake;

[0011] Step 4: Using laser cladding equipment and a coaxial powder feeding process, the TiAl-based intermetallic compound powder forms a metallurgical bond with the muzzle brake nozzle wall under the action of the laser. As the powder and the laser move on the nozzle wall surface, the metallurgical bond forms a cladding layer;

[0012] Step 5: Repeat step 4 to complete the preparation of the cladding layer on all the nozzle holes of the muzzle brake;

[0013] Step 6: Performing atmosphere protection stress relief annealing on the nozzle wall after cladding;

[0014] Step 7: Mechanically process the nozzle hole wall.

[0015] Preferably, an alkaline cleaning agent is used to clean the entire gun recoil brake, and then an acid cleaning agent is used to clean the wall surface of the gun recoil brake nozzle.

[0016] Preferably, the protective gas passing through the closed forming tool is a mixed gas of nitrogen and argon, and the flow rate of argon is 5-30 sccm.

[0017] Preferably, the temperature of the substrate is controlled at 400-500° C. during the preheating process, and the temperature of the substrate is maintained at above 500° C. in S4 .

[0018] Preferably, the laser power is 600W to 1050W, the laser scanning rate is 10 to 15 mm / s, and the scanning overlap rate is 40% to 60%.

[0019] Preferably, the powder-carrying gas flow for coaxial powder feeding is helium, the gas flow rate is 3 to 10 L / min, and the powder feeding rate is 5 to 15 g / min.

[0020] Preferably, the annealing temperature is 400° C. and the annealing time is 1 to 24 hours.

[0021] Preferably, the machining method is sand blasting, and the coating surface roughness of the nozzle hole wall is not higher than Ra0.4.

[0022] The present invention provides a method for strengthening the nozzle hole wall of a titanium alloy muzzle brake. Compared with the prior art, the method has the following outstanding features and excellent effects:

[0023] The present invention uses a laser cladding coaxial powder feeding method to prepare a TiAl-based intermetallic compound wear-resistant cladding layer on the nozzle wall of a titanium alloy recoil suppressor. During the process, a metallurgical reaction occurs between the coating and the substrate, which has a high bonding strength and improves the service life of the coating. Laser is used as a coating heat source, and the thermal deformation of the substrate is small, further alleviating the problem of coating cracking. By adjusting the amount of Ti2AlNb added, the overall plasticity of the material is increased, and by adding TiB2 ceramic particles to the TiAl-based intermetallic compound powder, the hardness and wear resistance of the coating are further enhanced.

[0024] The titanium alloy artillery muzzle brake prepared by this method has a coating thickness of no more than 0.5 mm, a substrate heat affected zone thickness of 1 mm, and a Ti2AlNb cladding layer hardness greater than 700 HV, which improves the hardness and wear resistance of the titanium alloy artillery muzzle brake nozzle and can significantly improve the service life of the titanium alloy artillery muzzle brake. At the same time, the process method has the advantages of simple process, strong operability, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A process flow chart for the embodiment of the present invention;

[0026] Figure 2 A schematic diagram of a titanium alloy muzzle brake shown in an embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of preparing a cladding layer on the nozzle wall of a titanium alloy muzzle brake by using a coaxial powder feeding laser cladding process as shown in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are 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 making creative work are within the scope of protection of the present invention.

[0029] The features of various aspects of the embodiments of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to fully understand the present invention. However, it is obvious to those skilled in the art that the present invention can also be implemented without these specific details. The following description of the embodiments is only for a better understanding of the present invention by illustrating examples of the present invention. The present invention is not limited to any specific settings and methods provided below, but covers all product structures, any improvements, replacements, etc. of methods covered without departing from the spirit of the present invention.

[0030] In the following description, well-known structures and technologies are not shown to avoid unnecessary ambiguity of the present invention. The preparation method of the ablation-resistant and wear-resistant coating of the nozzle hole of the titanium alloy gun recoil brake of the present invention is described below in conjunction with specific embodiments.

[0031] Example

[0032] An embodiment of the titanium alloy muzzle brake nozzle hole wall strengthening method of the present invention. The titanium alloy muzzle brake nozzle hole wall strengthening method described in this embodiment is:

[0033] (1) Use LCX-52 cleaning agent to thoroughly clean and dry the TC4 titanium alloy gun barrel recoil device 1 to remove surface impurities.

[0034] (2) The cleaned TC4 titanium alloy gun barrel deflector 1 is immersed in a pickling solution, wherein the nitric acid concentration in the pickling solution is 200 mL / L, the pickling temperature is 60° C., and the pickling time is 5 min; after the pickling is completed, it is washed with running water and dried to completely remove the oxide on the surface of the titanium alloy.

[0035] (3) TiAl-based intermetallic compound powder 3 is placed in a powder feeder, and a mixed gas of nitrogen and argon is used as the protective gas, the nitrogen content in the mixed gas is 50%, and the protective gas flow rate is 20L / min, thereby generating a certain proportion of TiN during the strengthening process to enhance the hardness of the coating. In the TiAl-based intermetallic compound powder 3, the volume percentage of TiAl powder is 55.0%, the volume percentage of Ti2AlNb powder is 42.0%, and the volume percentage of TiB2 powder is 3.0%. The particle size of TiAl powder is 45 to 106 microns, the particle size of Ti2AlNb powder is 53 to 150 microns, and the particle size of TiB2 powder is 8 to 12 microns. The TiAl alloy powder is composed of 48.0% Ti, 48.0% Al, 2.0% Cr, 2.0% Nb and 0.06% C by mass percentage. Ti2AlNb alloy powder is composed of 53.0% Ti, 22.0% Al, 25.0% Nb and 0.05% C by mass percentage. TiB2 powder is composed of 68% Ti, 31% B and 0.45% O by atomic percentage. The addition of Ti2AlNb powder can enhance the high temperature mechanical properties of the coating, and TiB2 powder further enhances the wear resistance. At the same time, the density of the coating is optimized by controlling the powder particle size.

[0036] (4) The area where the nozzle hole wall 2 is located is preheated, and the substrate temperature is controlled at 400-500°C. The substrate is continuously heated during the forming process, and the substrate temperature is continuously maintained above 500°C to prevent the coating from cracking.

[0037] (5) Then, a coaxial powder feeding mode is adopted, with helium as the powder carrier gas flow, a gas flow rate of 5 L / min, a powder feeding rate of 15 g / min, a laser power of 1000 W, a laser scanning rate of 12 mm / s, and a scanning overlap rate of 40%. Under the action of the laser 4, the TiAl-based intermetallic compound powder 3 melts on the nozzle wall 2 to form a molten pool. As the powder 3 and the laser 4 move, the molten pool area expands, and a coating is formed after solidification. The coating thus formed has high density, strong bonding force with the substrate interface, high hardness, and excellent anti-ablation performance.

[0038] (6) The TC4 titanium alloy cannon tube withdrawer 1 is subjected to stress relief annealing in an argon protective atmosphere, with an argon flow rate of 20 sccm, an annealing temperature of 400°C, and an annealing time of 24 h.

[0039] (7) Deep hole grinding is used to achieve the final size, and the coating surface roughness is Ra0.4, completing the entire strengthening process.

[0040] The obtained coating properties are shown in Table 1.

[0041] Table 1 Performance data of TC4 titanium alloy gun tube recoil device in Example

[0042]

[0043] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for strengthening the nozzle wall of a titanium alloy muzzle brake, characterized in that: The following steps are involved: S1: Cleaning and drying the titanium alloy artillery recoil brake; S2: placing TiAl-based intermetallic compound powder in a powder feeder of a laser cladding device, and passing protective gas in a closed forming tool; S3: preheating the nozzle wall of the muzzle brake; S4: Laser cladding equipment is used to process the nozzle wall by coaxial powder feeding. The TiAl-based intermetallic compound powder forms a metallurgical bond with the nozzle wall under the action of the laser. As the powder and the laser move on the surface of the nozzle wall, the metallurgical bond forms a cladding layer. S5: repeat S4 to complete the preparation of the cladding layer on all the nozzle holes of the muzzle brake; S6: performing atmosphere protection stress relief annealing on the nozzle wall after cladding; S7: machining the nozzle hole wall; The components of the TiAl-based intermetallic compound powder are composed by volume of: 40.0%-50.0% Ti2AlNb alloy powder, 1.0%-5.0% TiB2 ceramic particle powder, and the remainder is TiAl alloy powder; The particle size of the TiAl alloy powder is 45-106 μm, the particle size of the Ti2AlNb alloy powder is 53-150 μm, and the particle size of the TiB2 alloy powder is 8-12 μm; The shielding gas in S2 is a mixture of nitrogen and argon, and the shielding gas in S6 is argon; During the preheating process of S3, the substrate temperature is controlled at 400-500°C, and in S4, the substrate temperature is maintained above 500°C; The alkaline cleaning agent used in S1 is LCX-52 cleaning agent, and the nitric acid concentration in the acid cleaning agent used is 200mL / L; The coating thickness of the nozzle hole wall shall not exceed 0.5 mm.

2. The method for strengthening the nozzle hole wall of a titanium alloy muzzle brake according to claim 1, characterized in that: In the cleaning process of S1, an alkaline cleaning agent is used to clean the entire gun recoil brake, and then an acid cleaning agent is used to clean the wall surface of the gun recoil brake nozzle.

3. The method for strengthening the nozzle hole wall of a titanium alloy muzzle brake according to claim 1, characterized in that: In S4, the laser power is 600W to 1050W, the laser scanning rate is 10 to 15 mm / s, and the scanning overlap rate is 40% to 60%.

4. The method for strengthening the nozzle hole wall of a titanium alloy muzzle brake according to claim 1, characterized in that: In S4, the powder-carrying gas flow for coaxial powder feeding is helium, the gas flow rate is 3-10 L / min, and the powder feeding rate is 5-15 g / min.

5. The method for strengthening the nozzle hole wall of a titanium alloy muzzle brake according to claim 1, characterized in that: In S6, the annealing temperature is 400° C. and the annealing time is 1 to 24 hours.

6. The method for strengthening the nozzle hole wall of a titanium alloy muzzle brake according to claim 1, characterized in that: The machining method in S7 is sand blasting, and the coating surface roughness of the nozzle hole wall is not higher than Ra0.4.

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