Method and device for repairing crack-free high-temperature alloy through laser melting deposition based on three-dimensional path weaving

Abstract

The invention belongs to the field of metal material laser repair, discloses a high Al / Ti content nickel-based superalloy laser melting deposition repair cracking inhibition method and device, and provides a superalloy laser melting deposition repair method and device based on three-dimensional path weaving. The advantages of reducing stress concentration and preventing cracking of double-material deposition repair are combined, and meanwhile, the three-dimensional woven deposition strategy enables the repair layer not to generate mechanical property anisotropy. In addition, the special laser cladding head with six paths of powder feeding nozzles is used, and three powder feeding nozzles form a powder feeding unit of the laser cladding head, so that the laser cladding head is provided with two independent powder feeding units. The powder gates for opening or closing the two powder feeding units are positioned at the joint outside the powder feeding nozzle of the laser cladding head, so that a powder flowing path as short as possible between the powder gates and other powder feeding paths is ensured, the powder waste caused by frequent switching of the two powder feeding units is reduced, and the powder feeding interval time is shortened. And by combining the advantages of double-material three-dimensional weaving, crack-free laser melting deposition repair of the nickel-based high-temperature alloy with the high Al / Ti content is formed.

Description

Technical Field

[0001] The present invention belongs to the field of laser repair, and particularly relates to a method and device for cracking suppression in the laser melting deposition repair process of nickel-based superalloys with high Al / Ti content. Background Art

[0002] As the main material for the core engine in gas turbines and aero-engines, superalloys play an irreplaceable role in industrial development. In particular, the service environments of components such as turbine disks, turbine blades, and gas guide vanes in the core engine are extremely harsh, and the proportion of components damaged within the service life cycle is too large. The economic value of the above components is generally high, and direct replacement will incur high maintenance and support costs, which is an uneconomical option. However, laser melting deposition repair of locally damaged components and then putting them back into service can greatly reduce the replacement of new components and lower the maintenance and support costs. Generally speaking, superalloy components with excellent high-temperature strength have a high Al / Ti content and are prone to generating low-melting eutectic phases during solidification. At the same time, the heating and cooling rates in the laser melting deposition process are much higher than those in ordinary casting, resulting in high residual stresses. Therefore, when using laser melting deposition to repair nickel-based superalloy components with high Al / Ti content, cracks are extremely likely to occur, thus bringing difficulties to the field of repair of key components of superalloys.

[0003] Researchers in this field have made improvements in different ways to suppress crack generation during the laser melting deposition repair of superalloys, including powder composition modification, substrate heating to reduce the cooling rate, and layered deposition of two materials. Among them, powder composition modification can effectively prevent cracking, but changes in the basic composition may have potential impacts on the service performance of components; when using the substrate heating method to repair large-sized components, the requirements for the chamber and tooling are too high; the layered composite structure formed by layered deposition of two materials can reduce the stress during the laser melting deposition process to reduce the cracking tendency, but the material distribution is anisotropic, which is prone to potential hazards of anisotropic properties. Based on the above deficiencies, the present invention proposes a method and device for laser melting deposition repair of superalloys based on three-dimensional path weaving, which combines the advantages of dual-material deposition repair to reduce stress concentration and prevent cracking. At the same time, the three-dimensional weaving deposition strategy enables the repair layer not to generate mechanical property anisotropy. Summary of the Invention

[0004] The object of the present invention is to provide a repair method and device for laser coaxial synchronous powder feeding and cladding to repair high-aluminum / titanium content superalloy components using a three-dimensional weaving path strategy, and to repair damaged and failed components. The superalloy to be repaired is a nickel-based superalloy with an Al / Ti content ≥ 5%, and the method includes the following steps:

[0005] Step 1: Evaluate the nickel-based superalloy component to be repaired to determine the area to be repaired of the damaged component;

[0006] Step 2: Perform surface treatment on the part to be repaired. Use tools to cut off the secondary damage on the surface, grind and remove the excess scale, and clean the repaired surface after treatment with absolute ethanol.

[0007] Step 3: Conduct entity scanning or observation on the area to be repaired to determine the volume and area to be repaired and define the repair model.

[0008] Step 4: Use a dual-material laser cladding head required for three-dimensional weaving paths, which can deliver two types of powders, and the time for switching between the two powders is no more than 2 seconds.

[0009] Step 5: In order to maintain the good high-temperature performance of the high-aluminum / titanium content as much as possible, one of the two materials used in laser melting deposition repair is the same as the component of the workpiece to be repaired, and the other is a nickel-based superalloy powder with an Al / Ti content ≤ 2%. The laser coaxial powder feeding method is used to process the area to be repaired, and the cladding parameters are as follows: the laser power is 800 - 2000 W, the laser spot diameter is 2.5 - 3 mm, the powder feeding rate is 10 - 15 g / min, the powder sphericity S is between 0.8 and 1, the particle size distribution range is 70 - 150 μm, and a high-purity argon gas (purity ≥ 99.99%) atmosphere is used for protection during the laser melting deposition repair process.

[0010] Step 6: In order to achieve a powder feeding type switching time of no more than 2 seconds, it is completed using a special laser cladding head and an attached powder feeding system. It is characterized in that the laser cladding head uses coaxial powder feeding, and its basic structure is the same as that of a traditional powder feeding head, including a fiber optic interface, a collimating protection lens, a collimating lens, a focusing lens, a focusing protection lens, etc. The difference is that the laser cladding head in the present invention has six powder feeding nozzles, which are equally spaced on the circumference of the laser cladding head, and the angle between adjacent ones is 60 degrees.

[0011] Step 7: On the basis of the above laser cladding head, in order to shorten the time for switching between different types of powders, the six powder feeding nozzles in Step 6 are divided into two powder feeding units, each powder feeding unit consists of three powder feeding nozzles, and the angle between the three powder feeding nozzles in each powder feeding unit is 120 degrees.

[0012] Step 8: According to the feature in Step 7, three powder feeding nozzles form a powder feeding unit of the laser cladding head, so that the laser cladding head in the present invention has two independent powder feeding units.

[0013] Step 9: After forming two independent powder feeding units in Step 8, the laser cladding head in the present invention is fed with powder by two independent powder feeding devices, which respectively correspond to its two independent powder feeding units.

[0014] Step Ten: Further, the powder gates for opening or closing the two powder feeding units are located at the connection outside the powder feeding nozzle of the laser cladding head, ensuring the shortest possible powder flow path between the powder gates and the rest of the powder feeding path, reducing powder waste during frequent switching between the two powder feeding units, and shortening the powder feeding interval time;

[0015] Step Eleven: During cladding repair, the thickness of the cladding layer is not less than two layers, and the cladding directions between each layer are perpendicular to each other. Within the same layer, the dual materials used for repair are arranged crosswise;

[0016] Step Twelve: Further, according to the requirements of Step Eleven, when starting to clad the same layer, the first pass is made of a high Al / Ti content material identical to the substrate to be repaired, with a single-pass cladding width of 2 - 3.5 mm, and the second pass is made of the second material, which is a nickel-based superalloy with an Al / Ti content ≤ 2%. The cladding width of the second material is 1.5 - 2.4 mm; the overlap rate of the two materials is 35 - 55%, achieving the alternating arrangement of the dual materials in the same layer;

[0017] Step Thirteen: After Step Twelve, in order to form a three-dimensional braided structure, when cladding the next layer, the cladding direction is deflected by 45 - 90° compared to the previous layer, with every two layers forming a cycle;

[0018] Step Fourteen: Repeat Step Twelve and Step Thirteen, that is, keep the same layer composed of crosswise dual materials, and the cladding directions between different layers have a fixed deflection angle. Thus, a three-dimensional braided structure of dual materials is formed;

[0019] Advantages and beneficial effects of the present invention:

[0020] The present invention uses a laser melting deposition repair of a crack-free superalloy with a three-dimensional path braiding of dual materials. Through a specially designed laser cladding head with dual powder feeding units, it can reduce powder waste during frequent switching of dual materials and shorten the powder feeding interval time. It combines the advantages of multi-material deposition repair in reducing stress concentration and preventing cracking. At the same time, the three-dimensional braided deposition strategy enables the repair layer not to have mechanical property anisotropy. Description of the Drawings

[0021] Att Figure 1 is a schematic diagram of a dual-unit powder feeding laser cladding head provided by a specific embodiment of the present invention;

[0022] Att Figure 2 is a schematic diagram of a three-dimensional braided path of dual-material deposition in a specific embodiment of the present invention; Detailed Embodiments

[0023] The following further elaborates the present invention in combination with specific embodiments

[0024] Step 1: Evaluate the superalloy components to be repaired and determine the areas to be repaired on the damaged components;

[0025] Step 2: Perform surface treatment on the area to be repaired. Use tools to remove secondary damage on the surface, grind and remove excess scale, and clean the treated repair surface with anhydrous ethanol;

[0026] Step 3: Conduct entity scanning or observation on the area to be repaired to determine the volume and area to be repaired and establish the repair model;

[0027] Step 4: Use a dual-material laser cladding head required for three-dimensional weaving paths, which can deliver two types of powders, and the switching time between the two powders is no more than 2 seconds;

[0028] Step 5: To maintain the good high-temperature performance of the high Al / Ti content as much as possible, one of the two materials used in laser melting deposition repair is the same as the composition of the workpiece to be repaired. The commercial grade name of the substrate to be repaired is Inconel 738, and the other is a nickel-based superalloy powder with an Al / Ti content ≤ 2%. The commercial grade is Inconel 718. The laser coaxial powder feeding method is used to process the area to be repaired. The cladding parameters are as follows: laser power is 1000W, laser spot diameter is 2.5mm, powder feeding rate is 12g / min, laser scanning speed is 600mm / min, the powder sphericity S is between 0.8 and 1, the particle size distribution range is 70 - 150μm, and a high-purity argon gas (purity ≥ 99.99%) atmosphere is used for protection during the laser melting deposition repair process;

[0029] Step 6: To achieve a powder feeding type switching time of no more than 2 seconds, it is completed using a special laser cladding head and an affiliated powder feeding system. Its characteristics are that the laser cladding head uses coaxial powder feeding, and its basic structure is the same as that of a traditional powder feeding head, including a fiber optic interface, a collimating protection lens, a collimating lens, a focusing lens, a focusing protection lens, etc. The difference is that the laser cladding head in the present invention has six powder feeding nozzles, which are equally spaced on the circumference of the laser cladding head, and the angle between adjacent nozzles is 60 degrees;

[0030] Step 7: Based on the above laser cladding head, to shorten the switching time between different types of powders, the six powder feeding nozzles in Step 6 are divided into two powder feeding units, each powder feeding unit consists of three powder feeding nozzles, and the angle between the three powder feeding nozzles in each powder feeding unit is 120 degrees;

[0031] Step 8: According to the characteristics in Step 7, three powder feeding nozzles form a powder feeding unit of the laser cladding head, so that the laser cladding head in the present invention has two independent powder feeding units;

[0032] Step Nine: After the two independent powder feeding units are formed in Step Eight, the laser cladding head in the present invention is fed with powder by two independent powder feeding devices, which respectively correspond to its two independent powder feeding units, and their distribution is as shown in the appendix Figure 1 as shown;

[0033] Step Ten: Further, the powder gates for opening or closing the two powder feeding units are located at the connection outside the powder feeding nozzles of the laser cladding head, so as to ensure the shortest possible powder flow path between the powder gates and the rest of the powder feeding paths, reduce the powder waste during frequent switching of the two powder feeding units, and at the same time shorten the powder feeding interval time;

[0034] Step Eleven: During cladding repair, the thickness of the cladding layer is not less than two layers, and the cladding directions between each layer are perpendicular to each other. Within the same layer, the two materials used for repair are arranged crosswise.

[0035] Step Twelve: Further, according to the requirements of Step Eleven, when starting to clad the same layer, the first pass is made of the same material as the substrate to be repaired, Inconel 738, with a single-pass cladding width of 2.7 mm, and the second pass is made of the second material, which is an Inconel 718 nickel-based superalloy with an Al / Ti content ≤ 2%, and the cladding width of the second material is 2 mm; the overlapping rate of the two materials is 30%. Further, the alternating deposition path as shown in the appendix Figure 2 is used to achieve the alternating arrangement of the two materials in the same layer;

[0036] Step Thirteen: After Step Twelve, in order to form a three-dimensional braided structure, when cladding the next layer, as shown in the appendix Figure 2 as shown, the cladding direction is deflected by 90° compared with the previous layer;

[0037] Step Fourteen: Repeat Step Twelve and Step Thirteen, that is, keep the same layer composed of two materials crosswise, and the cladding directions between different layers have a fixed deflection angle. Thus, a three-dimensional braided repair structure of two materials is formed.

Claims

1. A method and device for repairing crack-free superalloys by laser melting deposition based on three-dimensional path weaving, characterized in that, The following steps are involved: Step 1, providing a method and device for repairing high-aluminum / titanium content high-temperature alloy components by laser coaxial synchronous powder feeding cladding using a three-dimensional weaving path strategy to repair damaged and failed components, wherein the repaired high-temperature alloy is a nickel-based high-temperature alloy with an Al / Ti content of ≥5%; Step 2, using a dual-material laser cladding head required for a three-dimensional weaving path, capable of delivering two types of powders, and the time taken to switch between the two types of powders is no more than 2 seconds; Step three, in order to maintain the good high-temperature performance of high aluminum / titanium content as much as possible, the dual materials used in laser melting deposition repair are one with the same composition as the workpiece to be repaired, and the other is a nickel-based high-temperature alloy powder with an Al / Ti content of ≤2%. The laser coaxial powder feeding method is used to process the area to be repaired, and the cladding parameters are: laser power of 800-2000W, laser spot diameter of 2.5-3mm, powder feeding amount of 10-15g / min, powder sphericity S between 0.8 and 1, and particle size distribution range of 70-150μm. High-purity argon (purity ≥99.99%) atmosphere protection is used during the laser melting deposition repair process.

2. The method and device for repairing crack-free superalloy by three-dimensional path weaving laser melting deposition according to claim 1, characterized in that, The following steps are involved: Step 4: In order to achieve a powder feeding type switching time of no more than 2 seconds, a special laser cladding head and an auxiliary powder feeding system are used, wherein the laser cladding head adopts coaxial powder feeding, and the basic structure is the same as that of a traditional powder feeding head, including an optical fiber interface, a collimating protection lens, a collimating lens, a focusing lens, a focusing protection lens and other structures. The difference is that the laser cladding head in the present invention has six-way powder feeding nozzles, and the six-way nozzles are equidistantly distributed on the circumference of the laser cladding head, and the angle between adjacent nozzles is 60 degrees; Step 5: Based on the above laser cladding head, in order to shorten the time of switching between different types of powders, the six-way powder feeding nozzle in step 6 is divided into two powder feeding units, each powder feeding unit consists of three powder feeding nozzles, and the angles between the three powder feeding nozzles in each powder feeding unit are 120 degrees; Step 6: According to the features in step 7, three powder feeding nozzles form a powder feeding unit of the laser cladding head, so that the laser cladding head of the present invention has two independent powder feeding units; Step 7, after the two independent powder feeding units are formed in step 8, the laser cladding head in the present invention is fed with powder by two independent powder feeding devices, which respectively correspond to the two independent powder feeding units; Step eight, further, the powder gates for opening or closing the two powder feeding units are located at the connection outside the powder feeding nozzle of the laser cladding head, ensuring that the powder flow path between the powder gate and the remaining powder feeding paths is as short as possible, reducing powder waste when the two powder feeding units are frequently switched, and shortening the powder feeding interval time.

3. The method and device for repairing crack-free superalloy by three-dimensional path weaving laser melting deposition according to claim 1, characterized in that, The following steps are involved: Step 9: During the cladding repair, the thickness of the cladding layer is not less than two layers, the cladding directions between each layer are perpendicular to each other, and within the same layer, the two materials used for repair are arranged crosswise with each other; Step ten, further, according to the requirements of step nine, when starting to clad the same layer, the first pass is made of a material with a high Al / Ti content identical to that of the substrate to be repaired, and the single-pass cladding width is 2 - 3.5 mm. The second pass is made of a second material, and the material selected is a nickel-based superalloy with an Al / Ti content ≤ 2%. The cladding width of the second material is 1.5 - 2.4 mm. The overlapping rate of the two materials is 35 - 55%, achieving the alternating arrangement of the two materials in the same layer; Step eleven, after step ten, in order to form a three-dimensional braided structure, when cladding the next layer, the cladding direction is deflected by 45 - 90° compared to the previous layer, and every two layers form a cycle; Step twelve, repeat step ten and step eleven, that is, keep the same layer composed of the cross of two materials, and there is a fixed deflection angle for the cladding direction between different layers, thereby forming a three-dimensional braided structure of two materials.

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