Laser composite additive remanufacturing process method

Abstract

The invention relates to the technical field of additive remanufacturing, and particularly discloses a laser composite additive remanufacturing process method which comprises the following steps: melting alloy powder through a laser cladding nozzle and spraying the alloy powder on a to-be-repaired surface to form a cladding layer; furthermore, volume damages in forms of corrosion holes, cracks, fractures and the like on the to-be-repaired part are repaired, and meanwhile, a laser impactor is used for carrying out laser impact strengthening on the cladding layer, so that the fatigue life strength of the cladding layer is improved. According to the device, a large amount of heat does not need to be input, then the influence on the mechanical property of an original to-be-repaired part can be reduced, laser shock strengthening is conducted on the cladding layer through the laser impactor, and the phenomena that the repaired layer is coarse in tissue dissimilation and unbalanced in residual stress distribution of the cladding layer are avoided.

Description

Technical Field

[0001] The present invention relates to the field of additive remanufacturing technology, and in particular to a laser composite additive remanufacturing process method. Background Art

[0002] The centrifugal force generated by high- and ultra-high-speed aircraft engines, combined with the impact of strong airflow, creates axial tension, non-directional distortion, and non-periodic, non-constant-amplitude vibration loads on the engine and its internal blades. Furthermore, the blade edges at the air intake and the tips of the front fan blades are susceptible to volumetric damage such as pitting, cracks, and fractures due to the combined effects of centrifugal force, air excitation, and the impact of rigid foreign objects carried by the strong airflow.

[0003] In the existing technology, micro-arc surfacing, high-speed arc spraying and flame spray melting are usually used to remanufacture damaged parts. Excessive heat input leads to a decrease in the mechanical properties of the remanufactured interface, the alienation and coarsening of the remanufactured coating structure, and uneven distribution of residual stress in the coating.

[0004] Therefore, there is an urgent need for laser composite additive remanufacturing process methods to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a laser composite additive remanufacturing process method to solve the problem that in the related art, micro-arc surfacing welding, high-speed arc spraying and flame spray melting are usually used to remanufacture damaged parts, and the heat input is too large, resulting in a decrease in the mechanical properties of the remanufactured interface, the alienation and coarsening of the remanufactured cladding structure, and the uneven distribution of residual stress in the cladding.

[0006] In one aspect, the present invention provides a laser composite additive remanufacturing process method, the laser composite additive remanufacturing process method comprising the following steps:

[0007] S10: Decontaminating the surface of the part to be repaired and grinding the surface to be repaired flat;

[0008] S20: preparing alloy powder for use in a laser cladding nozzle, wherein the ratio of each element in the alloy powder is the same as the ratio of each element in the material used for the part to be repaired;

[0009] S30: making the spray direction of the laser cladding nozzle perpendicular to the surface to be repaired, moving along the planned path of the surface to be repaired, and laying a cladding layer on the surface to be repaired;

[0010] The impact spot of the laser impactor and the cladding spot of the laser cladding nozzle move synchronously, and the impact beam of the laser impactor performs synchronous laser shock strengthening on the portion above the interface between the cladding layer and the part to be repaired and the portion below the interface to form a repair layer on the surface to be repaired;

[0011] S40: Determine whether the repair layer is flush with the surface of the part to be repaired. If so, execute S50; if not, execute S30;

[0012] S50: Determine whether the repair layer of the part to be repaired is qualified.

[0013] As a preferred technical solution of the laser composite additive remanufacturing process method, before executing S40, first execute S60;

[0014] S60: Stop the laser cladding nozzle and the laser impactor, and clean and decontaminate the repair layer on the surface to be repaired.

[0015] As a preferred technical solution of the laser composite additive remanufacturing process method, after executing S60 and before executing S40, first execute S70;

[0016] S70: The impact beam of the laser impactor performs laser shock strengthening on the two side surfaces of the repair layer perpendicular to the surface to be repaired. The process parameters of the laser shock are a power density of no more than 3gW / cm 2 , frequency is not higher than 2Hz, pulse width is not greater than 10ns, spot diameter is 2.5~3mm, and spot overlap rate is not greater than 30%.

[0017] As a preferred technical solution of the laser composite additive remanufacturing process method, S70 also includes: simultaneously forming a water constraint layer on the surface of the repair layer, and the thickness of the water constraint layer is 2 to 3 mm.

[0018] As the preferred technical solution for the laser composite additive remanufacturing process, S50 specifically includes:

[0019] S51: Performing a flaw detection on the surface of the repaired layer using a penetrant flaw detection method. If the flaw is qualified, proceed to S52; if the flaw is unqualified, proceed to S10;

[0020] S52: Using X-ray flaw detection method to detect the repair layer and the surface to be repaired, if qualified, execute S53, if unqualified, execute S10;

[0021] S53: Repair completed.

[0022] As a preferred technical solution of the laser composite additive remanufacturing process method, S30 also includes: the cladding spot of the laser cladding nozzle is 1 to 2 mm ahead of the impact spot of the laser impactor on the planned path.

[0023] As an optimal technical solution for the laser composite additive remanufacturing process method, S30 also includes: the impact spot of the laser impactor is 0.8 to 1.5 mm above the interface between the cladding layer and the part to be repaired, and 0.7 to 1.5 mm below the interface between the cladding layer and the part to be repaired.

[0024] As a preferred technical solution of the laser composite additive remanufacturing process method, S20 also includes: the alloy powder is spherical, and the powder particle size of the alloy powder is 50-150 μm.

[0025] As an optimal technical solution for the laser composite additive remanufacturing process method, S20 also includes: the alloy powder is mixed by ultrasonic vibration, the ultrasonic vibration time is 30 to 60 minutes, and the frequency is 18 to 20 kHz.

[0026] As an optimal technical solution for the laser composite additive remanufacturing process method, S20 also includes: placing the alloy powder in a vacuum drying oven, evacuating to below 0.2 MPa, then heating to 100°C-150°C, keeping warm for 1h-2h, and cooling to room temperature with the vacuum drying oven.

[0027] The beneficial effects of the present invention are:

[0028] The present invention provides a laser composite additive remanufacturing process method, which includes S10: decontaminating the to-be-repaired surface of the part to be repaired and smoothing the to-be-repaired surface; S20: preparing alloy powder for use with a laser cladding nozzle, wherein the ratio of each element in the alloy powder is the same as the ratio of each element in the material used for the part to be repaired; S30: making the spray direction of the laser cladding nozzle perpendicular to the to-be-repaired surface, moving along a planned path of the to-be-repaired surface, and laying a cladding layer on the to-be-repaired surface; the impact spot of the laser impactor and the cladding spot of the laser cladding nozzle move synchronously, and the impact beam of the laser impactor performs synchronous laser shock strengthening on the portion above and below the interface between the cladding layer and the part to be repaired, so as to form a repair layer on the to-be-repaired surface; S40: judging whether the repair layer is flush with the surface of the part to be repaired, and if so, executing S50; otherwise, executing S30; S50: judging whether the repair layer of the part to be repaired is qualified. The laser cladding nozzle melts the alloy powder and sprays it onto the surface to be repaired, forming a cladding layer. This repairs volumetric damage such as pitting, cracks, and fractures on the part to be repaired. Simultaneously, a laser impactor is used to laser shock strengthen the cladding layer, increasing its fatigue life strength. This device does not require a large amount of heat input, thereby reducing the impact on the mechanical properties of the original part to be repaired. Laser shock strengthening of the cladding layer by the laser impactor prevents the occurrence of structural abnormalities and coarsening in the repair layer, as well as uneven residual stress distribution in the cladding layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Flowchart of the laser composite additive remanufacturing process method according to an embodiment of the present invention;

[0030] Figure 2 This is a diagram of the equipment layout of the laser composite additive remanufacturing process method according to an embodiment of the present invention;

[0031] Figure 3 Schematic diagram of step S7 of the laser composite additive remanufacturing process method in an embodiment of the present invention.

[0032] In the picture:

[0033] 1. Parts to be repaired; 11. Surface to be repaired;

[0034] 2. Laser cladding nozzle; 21. Repair layer;

[0035] 3. Laser impactor; 31. Impact beam; 4. Water confinement layer emission end. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0039] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0040] like Figures 1 to 3 As shown, this embodiment provides a laser composite additive remanufacturing process method, which includes:

[0041] S10: Decontaminating the surface 11 of the part 1 to be repaired and grinding the surface 11 to be repaired flat.

[0042] In this step, taking a titanium alloy blade as an example, the surface corrosion of the titanium alloy blade's surface 11 to be repaired is removed, and a grinding wheel machine or an angle grinder is used to remove rust and burrs caused by corrosion or particle erosion, and the surface 11 to be repaired is ground flat.

[0043] S20: preparing alloy powder for use in the laser cladding nozzle 2 , wherein the ratio of each element in the alloy powder is the same as the ratio of each element in the material used for the part 1 to be repaired.

[0044] In this step, the component to be repaired is a titanium alloy blade as an example, and the main elements and mass percentages of the alloy powder are as follows: 5.50-6.80% Al, 3.40-4.50% V, 0.25-0.30% Fe, 0.05-0.10% C, and the balance is Ti.

[0045] Preferably, the main elements and their mass percentages are as follows: 6.50% Al, 3.85% V, 0.28% Fe, 0.08% C, and the balance is Ti.

[0046] Preferably, the alloy powder has a particle size of 50-150 μm and is spherical. This configuration facilitates rapid melting of the alloy powder. This value was determined through extensive testing.

[0047] In addition, according to the requirements of the specific working conditions of the titanium alloy blade for corrosion resistance and wear resistance, it can be chosen whether to add TiC powder uniformly mixed in a mass fraction of 10% to 30% to the alloy powder to improve the corrosion resistance and wear resistance of the cladding layer.

[0048] The alloy powder can be mixed using ultrasonic vibration, with a vibration time of 30 to 60 minutes, a frequency of 18 to 20 kHz, and a powder particle size of 50 to 150 μm. This setting can make the alloy powder more evenly mixed.

[0049] In addition, the alloy powder needs to be dried before being used in the laser cladding nozzle 2. Specifically, the alloy powder is placed in a vacuum drying oven, evacuated to below 0.2 MPa, then heated to 100-150°C, held at that temperature for 1-2 hours, and then cooled to room temperature in the vacuum drying oven. This setting can reduce the problem of bubbles in the cladding layer.

[0050] S30: The laser cladding nozzle 2 is moved in a spraying direction perpendicular to the surface to be repaired 11, along a planned path of the surface to be repaired 11, and a cladding layer is laid on the surface to be repaired 11;

[0051] The impact spot of the laser impactor 3 and the cladding spot of the laser cladding nozzle 2 move synchronously, and the impact beam 31 of the laser impactor 3 performs synchronous laser shock strengthening on the part above and below the interface between the cladding layer and the part to be repaired 1 to form a repair layer 21 on the surface to be repaired 11.

[0052] In this step, the cladding process adopts a four-way coaxial powder feeding method for cladding. The cladding process parameters are: laser power of 0.9-1.5kW, scanning speed of 4-7mm / s, powder feeding rate of 25-45g / min, carrier gas flow rate of 3-8L / min, circular spot with a spot diameter of 3-3.5mm, defocus of 3-5mm, beam energy showing Gaussian distribution, output mode of continuous output or pulse output. If the pulse output mode is used, the pulse width should be controlled between 10-15ms and the duty cycle should be 8:1-10:1. Argon is used as the molten pool shielding gas and powder feeding carrier gas, and the purity of argon is 99.99%.

[0053] The process parameters of laser shock are power density 6-8 gW / cm2, frequency 2-4 Hz, pulse width 12-15 ns, spot diameter 2.5-3 mm, and spot overlap rate 20-40%.

[0054] Optionally, S30 further includes: the cladding spot of the laser cladding nozzle 2 is 1 to 2 mm ahead of the impact spot of the laser impactor 3 on the planned path. This step can ensure that the cladding layer is impact-forged in the initial stage of solidification.

[0055] Optionally, S30 further includes: the impact spot of the laser impactor 3 is 0.8 to 1.5 mm above the interface between the cladding layer and the part to be repaired 1, and 0.7 to 1.5 mm below the interface between the cladding layer and the part to be repaired 1. In this step, the above arrangement ensures that the impact beam 31 reaches and covers all spatial locations above and below the interface through the shaping path planning, while minimizing the energy exposure to non-remanufacturing areas.

[0056] The part 1 to be repaired is fixed by a robotic arm, and the robotic arm holding the part to be repaired 1 is programmed in the reverse motion direction according to the planned path, so that the interactive position, time interval and order of the cladding beam and the impact beam 31 remain unchanged during the laser cladding and laser shock composite remanufacturing process, thereby realizing impact forging in the initial stage of melting, transformation and solidification of the cladding layer.

[0057] S40: Determine whether the repair layer 21 is flush with the surface of the part 1 to be repaired. If so, execute S50; otherwise, execute S30.

[0058] In this step, after laying a repair layer 21 on the surface to be repaired, determine whether it is flush with the surface of the part to be repaired 1. If it is flush, execute S50. If it is not flush, lay the repair layer 21 on the surface to be repaired again through step S30 until the repair layer 21 is flush with the surface of the part to be repaired 1.

[0059] Optionally, before executing S40, S60 is executed first; S60: Stop the laser cladding nozzle 2 and the laser impactor 3, and clean and decontaminate the repair layer 21 on the surface to be repaired 11. After the laser cladding nozzle 2 lays the repair layer 21 on the surface to be repaired 11, impurities such as slag inclusions may be present on the repair layer 21, which is not conducive to further laser cladding on the repair layer 21.

[0060] Optionally, after executing S60 and before executing S40, execute S70 first; S70: the impact beam 31 of the laser impactor 3 performs laser shock strengthening on the two sides of the repair layer 21 perpendicular to the surface to be repaired 11, and the process parameters of the laser shock are a power density of not more than 3gW / cm 2 , frequency no higher than 2 Hz, pulse width no greater than 10 ns, spot diameter 2.5-3 mm, and spot overlap rate no greater than 30%. In this step, the impact beam 31 of the laser impactor 3 performs laser shock strengthening on the two side surfaces of the repair layer 21 perpendicular to the surface to be repaired 11, further improving the fatigue life strength of the repair layer 21, causing elastic-plastic deformation on the material surface, and forming a deep residual compressive stress layer and a tissue strengthening layer.

[0061] Optionally, S70 also includes: simultaneously forming a water confinement layer on the surface of the repair layer 21, wherein the water confinement layer has a thickness of 2 to 3 mm. In this step, the laser shock wave utilizes the good penetration of laser light in water. When the laser pulse acts on the surface of the repair layer 21, it generates a high-pressure, high-stress rate plasma shock wave. The surface tension of water is used to constrain the direction of the shock wave, thereby effectively increasing the duration and force of the shock wave on the surface of the repair layer 21.

[0062] Specifically, the water confinement layer is provided by the water confinement layer emitting end 4 .

[0063] S50 specifically includes:

[0064] S51: Perform flaw detection on the surface of the repair layer 21 using a penetrant flaw detection method. If the flaw detection is qualified, execute S52; if the flaw detection is unqualified, execute S10.

[0065] In this step, the surface of the repair layer 21 of the titanium alloy blade is inspected for defects such as cracks, pores, and poor fusion by using penetrant testing. If the surface is qualified, the process proceeds to S52; if not, the process proceeds to S10.

[0066] S52: Use X-ray flaw detection to detect the repair layer 21 and the surface to be repaired 11. If they are qualified, execute S53; if they are unqualified, execute S10.

[0067] In this step, X-ray flaw detection is used to monitor the defects such as cracks and pores below the repair layer 21 and the surface to be repaired 11 of the titanium alloy blade. If qualified, execute S53; if unqualified, execute S10.

[0068] S53: Repair completed.

[0069] The laser cladding nozzle 2 melts the alloy powder and sprays it onto the repaired surface 11 to form a cladding layer, repairing volumetric damage such as pitting, cracks, and fractures on the repaired part 1. Simultaneously, a laser impactor 3 performs laser shock peening on the cladding layer to improve its fatigue life strength. This device eliminates the need for significant heat input, minimizing the impact on the mechanical properties of the original repaired part. Laser shock peening of the cladding layer by the laser impactor 3 prevents the formation of coarse and disorganized structures in the repaired layer 21 and uneven residual stress distribution within the cladding.

[0070] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A laser composite additive remanufacturing process, characterized in that: The following steps are involved: S10: Decontaminating the surface to be repaired (11) of the part to be repaired (1) and smoothing the surface to be repaired (11); S20: preparing alloy powder for use in the laser cladding nozzle (2), wherein the ratio of the elements in the alloy powder is the same as the ratio of the elements in the material used for the part to be repaired (1); S30: making the spray direction of the laser cladding nozzle (2) perpendicular to the surface to be repaired (11), moving along the planned path of the surface to be repaired (11), and laying a cladding layer on the surface to be repaired (11); The impact spot of the laser impactor (3) and the cladding spot of the laser cladding nozzle (2) move synchronously, and the impact beam (31) of the laser impactor (3) performs synchronous laser shock strengthening on the portion above the interface and the portion below the interface between the cladding layer and the part to be repaired (1), so as to form a repair layer (21) on the surface to be repaired (11); S40: Determine whether the repair layer (21) is flush with the surface of the part to be repaired (1); if so, execute S50; if not, execute S30; S50: Determine whether the repair layer (21) of the part to be repaired (1) is qualified.

2. The laser composite additive remanufacturing process according to claim 1, characterized in that: Before executing S40, execute S60 first; S60: Stop the laser cladding nozzle (2) and the laser impactor (3), and clean and decontaminate the repair layer (21) on the surface to be repaired (11).

3. The laser composite additive remanufacturing process according to claim 2, characterized in that: After executing S60 and before executing S40, execute S70 first; S70: The impact beam (31) of the laser impact device (3) performs laser impact strengthening on the two side surfaces of the repair layer (21) perpendicular to the surface to be repaired (11), and the process parameters of the laser impact are a power density of not more than 3gW / cm 2 , frequency is not higher than 2Hz, pulse width is not greater than 10ns, spot diameter is 2.5~3mm, and spot overlap rate is not greater than 30%.

4. The laser composite additive remanufacturing process according to claim 3, characterized in that: S70 also includes: simultaneously forming a water constraint layer on the surface of the repair layer (21), wherein the thickness of the water constraint layer is 2 to 3 mm.

5. The laser composite additive remanufacturing process according to claim 1, characterized in that: S50 specifically includes: S51: Perform flaw detection on the surface of the repair layer (21) using a penetrant flaw detection method. If the flaw is qualified, execute S52; if the flaw is unqualified, execute S10; S52: Using X-ray flaw detection method to detect the repair layer (21) and the surface to be repaired (11), if qualified, execute S53, if unqualified, execute S10; S53: Repair completed.

6. The laser composite additive remanufacturing process according to claim 1, characterized in that: S30 also includes: the cladding spot of the laser cladding nozzle (2) precedes the impact spot of the laser impactor (3) by 1 to 2 mm on the planned path.

7. The laser composite additive remanufacturing process according to claim 1, characterized in that: S30 also includes: the impact spot of the laser impactor (3) is 0.8 to 1.5 mm above the interface between the cladding layer and the part to be repaired (1), and 0.7 to 1.5 mm below the interface between the cladding layer and the part to be repaired (1).

8. The laser composite additive remanufacturing process according to claim 1, characterized in that: S20 also includes: the alloy powder is spherical, and the powder particle size of the alloy powder is 50-150 μm.

9. The laser composite additive remanufacturing process according to claim 1, characterized in that: S20 also includes: mixing the alloy powder by ultrasonic vibration, wherein the ultrasonic vibration time is 30 to 60 minutes and the frequency is 18 to 20 KHz.

10. The laser composite additive remanufacturing process according to claim 1, characterized in that: S20 also includes: placing the alloy powder in a vacuum drying oven, evacuating the vacuum to below 0.2 MPa, then heating to 100° C.-150° C., keeping the temperature for 1 h-2 h, and cooling to room temperature along with the vacuum drying oven.

Images