A solid phase repair device and method for point defect low thermal damage and local precise strengthening

Abstract

The application discloses a solid-phase repairing device and method with low thermal damage and local precise strengthening, and relates to a solid-phase repairing device and method. The application is used for solving the problems of pores, micro-cracks, loose structure and inclusions in a cast metal structural part. The solid-phase repairing device comprises a static sleeve, a reciprocating hollow shaft shoulder and an internal rotatable stirring working part; the lower part of the internal rotatable stirring working part is inserted into the upper end of the reciprocating hollow shaft shoulder from top to bottom, and the lower part of the reciprocating hollow shaft shoulder is inserted into the upper end of the static sleeve from top to bottom. The application belongs to the field of repairing and remanufacturing technology.

Description

Technical Field

[0001] This invention relates to a solid-phase repair device and method, belonging to the field of repair and remanufacturing technology. Background Technology

[0002] The aerospace industry's extreme demands for lightweight structures and high specific strength have made cast aluminum alloys (such as ZL205A and ZL114A) and magnesium alloys (such as ZM5 and ZM6) core materials for critical components such as aircraft fuselages, cabins, and engine mounts. During the forming process, these lightweight alloy castings are highly susceptible to point defects and localized volume defects such as porosity, shrinkage cavities, microcracks, and inclusions due to factors such as solidification shrinkage, gas release, and process fluctuations. These defects significantly reduce the fatigue life, load-bearing capacity, and airtightness of the components, directly threatening the service safety and reliability of aerospace equipment. In traditional production methods, defective castings are often scrapped, resulting in significant waste of materials and manufacturing costs. Currently, defect repair in cast lightweight alloys mainly relies on two categories: fusion welding techniques (argon arc welding, laser cladding, electron beam welding) and traditional solid-state repair techniques (conventional friction stir repair, cold spraying). Fusion welding repair requires melting the base material and filler material into a liquid phase. The high temperature causes a sharp increase in grain size, coarsening and segregation of precipitates in the heat-affected zone of aluminum and magnesium alloys, and even overheating and eutectic liquefaction. The mechanical properties of the repaired area are typically only 60%-80% of the base material, far below the strength / near-strength repair standards for aerospace components. In particular, it has poor adaptability for point defect repair. Fusion welding requires pre-excavation of the defect and the formation of a large bevel. For small point defects (φ0.5-2mm) and localized looseness, the "excavation-filling" repair can excessively damage the base material matrix and makes precise localized repair difficult. While solid-state technologies, such as friction stir repair (FSR), avoid melting, their adaptability to defects is insufficient. Conventional FSR mainly targets planar and linear defects (such as welds and grooves), making it difficult to achieve precise and efficient local repair of randomly distributed isolated point defects and localized volume defects (such as single pores and small-area shrinkage cavities) in castings. Domestically, the Shanghai Aerospace Precision Machinery Research Institute, the China Academy of Aeronautical Manufacturing Technology, and Beijing University of Technology have established a series of FSR patents (such as CN106392460A and CN112609068A), primarily focusing on defect filling, multi-pass stirring, and auxiliary heat source coupling. However, patents for solid-state repair methods and dedicated devices that integrate "localization, non-filling, repair, and strengthening" for point defects in cast alloys are extremely rare. Existing technologies generally suffer from shortcomings such as large repair areas, low precision, lack of strengthening function, and poor equipment versatility. A complete technical solution capable of achieving "precise targeted repair of point defects + localized structural strengthening" has not yet been formed, becoming a core technological gap restricting high-quality repair of lightweight alloys in aerospace castings.

[0003] In summary, the development of a solid-phase repair method and device that features low thermal damage, precise localization, and integrated repair and strengthening overcomes the bottlenecks of existing technologies in the repair of point defects in aerospace cast aluminum and magnesium alloys, such as thermal degradation, insufficient performance, and poor adaptability. This has significant engineering value for improving the yield of aerospace components, reducing manufacturing costs, and ensuring the safe operation of equipment. Summary of the Invention

[0004] This invention addresses the problems of porosity, microcracks, loose structure, and inclusions in cast metal structural parts, and proposes a solid-phase repair device and method for point defects with low thermal damage and precise local strengthening.

[0005] The technical solution adopted by the present invention to solve the above problems is as follows: The solid-phase repair device for point defects with low thermal damage and local precise reinforcement includes a stationary sleeve, a reciprocating hollow shoulder, and an internally rotatable stirring working part; the lower part of the internally rotatable stirring working part is inserted into the upper end of the reciprocating hollow shoulder from top to bottom, and the lower part of the reciprocating hollow shoulder is inserted into the upper end of the stationary sleeve from top to bottom.

[0006] Furthermore, the stationary sleeve is provided with a feeding hole for introducing the wire.

[0007] Furthermore, the outer wall of the lower part of the reciprocating hollow shoulder is provided with threads that mate with the threads on the inner wall of the stationary sleeve.

[0008] Furthermore, the outer wall of the internally rotatable stirring part is provided with reverse threads, and the end face of the internally rotatable stirring part is provided with a concave structure and tiny protrusions.

[0009] The steps of the solid-phase repair method for point defects with low thermal damage and precise local reinforcement according to the present invention include: Step 1: Design the dimensions of the stationary sleeve, the reciprocating hollow shoulder, and the internal rotatable stirring working part to ensure a wide range of thermomechanical coupling flow of the material, so as to fill the point defects caused by local material deficiency and enhance the metallurgical bonding of the interface. Step 2: Wipe the area to be repaired and the filling material with anhydrous ethanol to remove surface oil; sand the surface of the area to be welded with sandpaper to remove impurities; Step 3: Fix the casting workpiece to be repaired on the operating table using tooling fixtures to prevent the casting workpiece to be repaired from moving during the solid phase repair process; Step 4: During repair, the stationary sleeve is first pressed down to make close contact with the surface of the workpiece to be repaired, so as to prevent the thermoplastic material inside the stationary sleeve from overflowing into the repair area. Simultaneously, the reciprocating hollow shoulder begins to retract upwards, while the internal rotatable stirring part plunges into the workpiece, reaching the defect location to stir, mix, and repair the defect. At this time, the thermoplastic material caused by the internal rotatable stirring part flowing upwards into the space formed when the reciprocating hollow shoulder retracts. After the internal rotatable stirring part continues to rotate and stays for a certain period of time, it retracts, and the reciprocating hollow shoulder rotates and presses down again. Simultaneously, the filling wire is gradually fed in. Under the action of the external threads of the reciprocating hollow shoulder, it is continuously sheared, broken, and thermoplasticized, mixing with the thermoplastic material of the casting body, and further filling the repair area, forming complete filling of the defect and the formation of local excess height, thus achieving precise reinforcement of the repair area. Step 5: Repair complete. The repair is gradually pulled back and removed from the surface of the cast component, resulting in a repair joint with low thermal damage and precise local reinforcement.

[0010] Furthermore, the thickness of the cast components is 2~1000mm, the defect depth is 0.1~50mm, and the defect range is 1~100mm. .

[0011] Furthermore, the gap between the stationary sleeve and the reciprocating hollow shoulder is 0.1~1mm, the gap between the reciprocating hollow shoulder and the internal rotatable stirring part is 0.1~1mm, the diameter of the internal rotatable stirring part is 1~10mm, the inner diameter of the reciprocating hollow shoulder is 0.1~1mm larger than the outer diameter of the internal rotatable stirring part, the outer diameter of the reciprocating hollow shoulder is 5~20mm larger than the inner diameter of the internal rotatable stirring part, the inner diameter of the stationary sleeve should be 0.1~1mm larger than the outer diameter of the reciprocating hollow shoulder, and the outer diameter of the stationary sleeve is 3~30mm larger than the inner diameter of the reciprocating hollow shoulder.

[0012] Furthermore, the gap between the stationary sleeve and the cast component is 0~1mm; the retraction distance of the reciprocating hollow shoulder is 0~30mm, and the rotation speed is between 100~5000rpm; the penetration depth of the internal rotatable stirring working part is between 0~50mm, and the rotation speed is between 50~5000rpm.

[0013] The beneficial effects of this invention are: 1. This invention can achieve low thermal damage and precise local reinforcement of point defects. By introducing external materials, it can avoid the factors of poor filling of the repair area caused by the reciprocating motion of the repair system and the overflow of materials in the gaps. Simultaneously introducing additional materials can play the role of "strengthening the weak". By designing reasonable reinforcing filling materials, local reinforcement of the repair area can be achieved. 2. After filling and repair, local areas can be treated with equal thickness or local excess height to further enhance the performance of the repaired area and avoid stress concentration. 3. Because the materials do not melt during the entire repair process, and the thermoplasticization of the filler material occurs inside the repair tool system, the present invention reduces the occurrence of thermal damage caused by the relative frictional heat generated between the stirring working part and the casting component, which is conducive to achieving high-quality repair with low thermal damage. 4. This invention is equipped with a robotic arm device, which can realize solid-phase repair of point defects in all positions of cast components. Through the mutual coordination of repair parameters, it can achieve second-level repair and rapid manufacturing. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a solid-phase repair device for point defects with low thermal damage and precise local enhancement. Figure 2 This is a schematic diagram of the internally rotatable stirring working part; Figure 3 This is a schematic diagram of a hollow shoulder capable of reciprocating motion; Figure 4 This is a schematic diagram of the stationary sleeve. Figure 5 This is a cross-sectional view of the solid-phase repair device; Figures 1 to 5 In the middle, 1-stationary sleeve, 2-reciprocating hollow shoulder, 3-internal rotatable stirring working part. Detailed Implementation

[0015] Specific implementation method one: as follows Figures 1 to 5The solid-phase repair device for point defects with low thermal damage and precise local reinforcement described in this embodiment includes a stationary sleeve 1, a reciprocating hollow shoulder 2, and an internally rotatable stirring part 3. The internally rotatable stirring part 3 is inserted into the reciprocating hollow shoulder 2, and the reciprocating hollow shoulder 2 is inserted into the stationary sleeve 1. The three components are positioned in a mating manner to avoid mutual contact and friction that generates heat. The stationary sleeve 1 is provided with a feeding hole to allow the introduction of filling rods or wires. The outer side of the reciprocating hollow shoulder 2 has screw features with a large pitch and threads, which, through interaction with the stationary sleeve... The interaction of the cylinders 1 ensures continuous shearing, thermoplasticization, and transport of the material, allowing the filler material to be quickly delivered to the location of the defect to be repaired. The sidewalls of the internal rotatable stirring section 3 have reverse threads to prevent thermoplasticized material from flowing into the gap between the reciprocating hollow shoulder 2 and the internal rotatable stirring section 3, thus preventing increased heat generation. The end face of the internal rotatable stirring section 3 has a concave structure and micro-protrusions, which helps to enhance the flow of material in the repair area and achieve precise elimination of local defects. At the same time, when the concave structure is pulled back, it can ensure the formation of a local excess height on the surface of the repair area, enhancing the load-bearing capacity of the repair area. Through the interaction of the above three components, low-heat damage and precise local strengthening repair of internal defects in cast metal can be achieved.

[0016] In this embodiment, the relative rotation and reciprocating motion between the stationary sleeve 1, the reciprocating hollow shoulder 2, and the internally rotatable stirring working part 3, as well as the introduction of external filling material, achieve the shearing, thermoplasticization, localized precise transport, and deposition filling of the material to be filled, thus meeting the needs for high-quality repair of local point defects.

[0017] Specific implementation method two: such as Figures 1 to 5 As shown, the steps of the solid-phase repair method for point defects with low thermal damage and precise local reinforcement described in this embodiment include: Step 1: Based on the different defect sizes and performance requirements inside the cast metal components, design the dimensions of the stationary sleeve, the reciprocating hollow shoulder, and the internally rotatable stirring working part to ensure a large-scale thermomechanical coupling flow of the material, so as to fill the point defects caused by local material deficiency and enhance the metallurgical bonding of the interface. Step 2: Wipe the area to be repaired and the filling material with anhydrous ethanol or acetone to remove surface oil and dirt; sand the surface of the area to be welded with sandpaper to remove impurities; Step 3: Fix the casting workpiece to be repaired on the operating table using tooling fixtures to prevent the casting workpiece from moving during the solid phase repair process; Step 4: During repair, the stationary sleeve is first pressed down to make close contact with the surface of the workpiece to be repaired, preventing the thermoplastic material inside the stationary sleeve from overflowing into the repair area. Simultaneously, the reciprocating hollow shoulder begins to retract upwards, and the internal rotatable stirring part plunges into the workpiece, reaching the defect location to stir, mix, and repair the defect. At this time, the thermoplastic material caused by the rotatable stirring part flowing upwards into the space formed when the reciprocating hollow shoulder retracts. After the rotatable stirring part continues to rotate and stays for a certain period of time, it retracts, and the hollow shoulder rotates and presses down again. Simultaneously, the wire or rod to be filled is gradually fed in. Under the action of the external thread of the stirring hollow shoulder, it is continuously sheared, broken, and thermoplasticized, mixing with the thermoplastic material of the casting body, further filling the repair area, forming complete filling of the defect and the formation of local excess height, achieving precise strengthening of the repair area. Step 5: Repair complete. The repair is gradually pulled back and removed from the surface of the cast component, resulting in a repair joint with low thermal damage and precise local reinforcement.

[0018] The thickness of the cast components ranges from 2 to 1000 mm, the defect depth from 0.1 to 50 mm, and the defect range from 1 to 100 mm. .

[0019] The gap between the stationary sleeve 1 and the reciprocating hollow shoulder 2 is 0.1~1mm. The gap between the reciprocating hollow shoulder 2 and the internal rotatable stirring part 3 is 0.1~1mm. The diameter of the internal rotatable stirring part 3 is 1~10mm. The inner diameter of the reciprocating hollow shoulder 2 is 0.1~1mm larger than the outer diameter of the internal rotatable stirring part 3. The outer diameter of the reciprocating hollow shoulder 2 is 5~20mm larger than the inner diameter of the internal rotatable stirring part 3. The inner diameter of the stationary sleeve 1 should be 0.1~1mm larger than the outer diameter of the reciprocating hollow shoulder 2. The outer diameter of the stationary sleeve 1 is 3~30mm larger than the inner diameter of the reciprocating hollow shoulder 2.

[0020] The gap between the stationary sleeve 1 and the cast component is 0~1mm; the retraction distance of the reciprocating hollow shoulder 2 is 0~30mm, and the rotation speed is between 100~5000rpm; the internal rotatable stirring working part 3 has an insertion depth of 0~50mm and a rotation speed of 50~5000rpm.

[0021] Among them, the metallic materials are a full range of lightweight alloys such as aluminum alloys, magnesium alloys, and magnesium-lithium alloys.

[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A solid-phase repair device for point defects with low thermal damage and precise local reinforcement, characterized in that, It includes a stationary sleeve (1), a reciprocating hollow shoulder (2), and an internally rotatable stirring working part (3); the lower part of the internally rotatable stirring working part (3) is inserted from top to bottom into the upper end of the reciprocating hollow shoulder (2), and the lower part of the reciprocating hollow shoulder (2) is inserted from top to bottom into the upper end of the stationary sleeve (1).

2. The solid-phase repair device for point defects with low thermal damage and precise local reinforcement according to claim 1, characterized in that, The stationary sleeve (1) is provided with a feeding hole for introducing wire.

3. The solid-phase repair device for point defects with low thermal damage and precise local reinforcement according to claim 1, characterized in that, The outer side wall of the lower part of the reciprocating hollow shoulder (2) is provided with a thread that matches the thread of the inner wall of the stationary sleeve (1).

4. The solid-phase repair device for point defects with low thermal damage and precise local reinforcement according to claim 1, characterized in that, The outer wall of the internally rotatable stirring working part (3) is provided with reverse threads, and the end face of the internally rotatable stirring working part (3) is provided with a concave structure and tiny protrusions.

5. A solid-phase repair method for point defects with low thermal damage and precise local reinforcement, characterized in that, The specific steps include: Step 1: Design the dimensions of the stationary sleeve (1), the reciprocating hollow shoulder (2), and the internal rotatable stirring working part (3) to ensure the thermomechanical coupling flow of the material over a large range, so as to fill the point defects caused by local material deficiency and enhance the metallurgical bonding of the interface. Step 2: Wipe the area to be repaired and the filling material with anhydrous ethanol to remove surface oil; sand the surface of the area to be welded with sandpaper to remove impurities; Step 3: Fix the casting workpiece to be repaired on the operating table using tooling fixtures to prevent the casting workpiece to be repaired from moving during the solid phase repair process; Step 4: During repair, the stationary sleeve is first pressed down to make close contact with the surface of the workpiece to be repaired, so as to prevent the thermoplastic material inside the stationary sleeve from overflowing into the repair area. Simultaneously, the reciprocating hollow shoulder (2) begins to retract upwards, and the internal rotatable stirring part (3) plunges into the workpiece, reaching the defect location to stir, mix, and repair the defect. At this time, the thermoplastic material caused by the internal rotatable stirring part (3) flowing upwards and into the space formed when the reciprocating hollow shoulder (2) retracts. After the internal rotatable stirring part (3) continues to rotate and stays for a certain period of time, the stirring part retracts, and the reciprocating hollow shoulder (2) rotates and presses down again. Simultaneously, the filling wire is gradually fed in. Under the action of the external thread of the reciprocating hollow shoulder (2), it is continuously sheared, broken, and thermoplasticized, and mixed with the thermoplastic material of the casting body. It further fills the repair area, forming complete filling of the defect and the formation of local excess height, thus achieving precise strengthening of the repair area. Step 5: Repair complete. The repair is gradually pulled back and removed from the surface of the cast component, resulting in a repair joint with low thermal damage and precise local reinforcement.

6. A solid-phase repair method for point defects with low thermal damage and precise local reinforcement according to claim 5, characterized in that, The thickness of the cast components ranges from 2 to 1000 mm, the defect depth from 0.1 to 50 mm, and the defect range from 1 to 100 mm. .

7. A solid-phase repair method for point defects with low thermal damage and precise local reinforcement according to claim 5, characterized in that, The gap between the stationary sleeve (1) and the reciprocating hollow shoulder (2) is 0.1~1mm. The gap between the reciprocating hollow shoulder (2) and the internal rotatable stirring part (3) is 0.1~1mm. The diameter of the internal rotatable stirring part (3) is 1~10mm. The inner diameter of the reciprocating hollow shoulder (2) is 0.1~1mm larger than the outer diameter of the internal rotatable stirring part (3). The outer diameter of the reciprocating hollow shoulder (2) is 5~20mm larger than the inner diameter of the internal rotatable stirring part (3). The inner diameter of the stationary sleeve (1) should be 0.1~1mm larger than the outer diameter of the reciprocating hollow shoulder (2). The outer diameter of the stationary sleeve (1) is 3~30mm larger than the inner diameter of the reciprocating hollow shoulder (2).

8. A solid-phase repair method for point defects with low thermal damage and precise local reinforcement according to claim 5, characterized in that, The gap between the stationary sleeve (1) and the cast component is 0~1mm; the retraction distance of the reciprocating hollow shoulder (2) is 0~30mm, and the rotation speed is between 100~5000rpm; the internal rotatable stirring working part (3) is inserted to a depth of 0~50mm, and the rotation speed is between 50~5000rpm.

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