Structure and method for repairing fractured boss of shell of SiC aluminum matrix composite product

Abstract

The invention belongs to the technical field of SiC aluminum matrix composite machining, and discloses a structure and a method for repairing a fractured boss of a SiC aluminum matrix composite product shell, the repairing structure comprises the SiC aluminum matrix composite product shell, a repairing groove is machined in the fractured boss area of the shell, an insert with an imitated boss is assembled in the repairing groove, and the imitated boss is arranged in the insert. And the repairing groove and the insert are fixed through a positioning pin and a countersunk screw. The groove and the insert are designed, a traditional welding mode is abandoned, the repairing groove is machined in the position of the broken boss of the product, and the insert with the protruding step is assembled; a positioning pin is specially arranged between the insert and the repairing groove, so that the positioning is reliable, and the precision is high enough; and the insert and the repairing groove are fixed through a screw, concave-convex matching and gluing, so that the insert and the repairing groove are firmly reinforced.

Description

Technical Field

[0001] The present invention belongs to the technical field of machining of SiC aluminum matrix composites, and relates to the repair of broken bosses, specifically to a repair structure and method for the fracture of the boss of a SiC aluminum matrix composite product shell. Background Art

[0002] SiC aluminum matrix composites have the characteristics of high specific strength, high specific modulus, low thermal expansion coefficient, good anti-wear performance, etc. However, when machining bosses or making holes on bosses of SiC aluminum matrix composite products, the problem of boss fracture often occurs. According to known situations, cracks originate from the back of the unpenetrated part in the direction of the drill bit outlet at the bottom of the drill hole, and then expand upward, left and right, eventually leading to the fracture of the boss. The reason is that during the high-speed rotation of the drill bit used in machining, extrusion friction occurs with the material, resulting in wear, a decrease in sharpness, an increase in cutting force, and an increase in machining axial force, thereby leading to the fracture of the boss.

[0003] For large-diameter product shells, directly scrapping them after the boss fractures will cause significant economic losses, and repair has to be carried out. Existing technologies usually use welding methods. However, for product shells with most dimensions already finely machined, if surfacing welding is used, the product shell will receive a large amount of heat input and is likely to undergo large deformation. Therefore, there is an urgent need to find a new repair method. Summary of the Invention

[0004] The purpose of the present invention is to provide a repair structure and method for the fracture of the boss of a SiC aluminum matrix composite product shell. The key to this method lies in "groove + insert", that is, abandoning the traditional welding method, machining a repair groove at the fractured boss of the product, and assembling an insert with a protruding step; a positioning pin is specially configured between the insert and the repair groove to ensure reliable positioning and high precision; the insert and the repair groove are fixed by "screw + concave-convex fit + glue" in three ways to strengthen and reinforce. Compared with the traditional welding method, the repair method proposed by the present invention can significantly improve the overall precision after repair, and is convenient for replacement and maintenance, with high practical value.

[0005] The present invention is implemented by adopting the following technical solutions: In the first aspect, the present invention provides a repair structure for the fracture of the boss of a SiC aluminum matrix composite product shell, including a SiC aluminum matrix composite product shell, a repair groove is machined in the boss fracture area of the SiC aluminum matrix composite product shell, and an insert with an imitation boss is assembled in the repair groove: The repair groove includes a first-order card slot, and a second-order card slot is machined in the middle of the first-order card slot; positioning pin holes A and mounting threaded holes A are respectively machined in the two side areas of the first-order card slot; A clamping block is machined on the middle of the back of the imitation boss of the insert, and a positioning pin hole B and a mounting counterbore B are respectively machined on both sides of the imitation boss corresponding to the positioning pin hole A and the mounting threaded hole A of the first-order clamping groove; A positioning pin is inserted into the positioning pin hole A and the positioning pin hole B; A countersunk head screw is screwed into the mounting threaded hole A and the mounting counterbore B.

[0006] Further preferably, the insert is made of SiC aluminum matrix composite material.

[0007] Further preferably, the first-order clamping groove and the second-order clamping groove of the repair groove and the imitation boss and the clamping block of the insert are bonded by epoxy glue.

[0008] Further preferably, the positioning pin is coated with anaerobic glue.

[0009] Further preferably, the countersunk head screw is coated with sealant.

[0010] Further preferably, the mounting threaded hole A is close to the second-order clamping groove and is symmetrically arranged on both sides of the second-order clamping groove; the positioning pin hole A is far from the second-order clamping groove and is symmetrically arranged on both sides of the second-order clamping groove.

[0011] In a second aspect, the present invention also provides a repair method for the fracture of the boss of the SiC aluminum matrix composite material product shell, based on the above repair structure for the fracture of the boss of the SiC aluminum matrix composite material product shell, including the following steps: S1. Groove machining: At the fractured boss of the SiC aluminum matrix composite material product shell, a repair groove is machined; the repair groove includes a first-order clamping groove, and a second-order clamping groove is machined in the middle of the first-order clamping groove; positioning pin holes A and mounting threaded holes A are respectively machined in both side regions of the first-order clamping groove 11; S2. Design and machining of the insert: According to the boss structure of the SiC aluminum matrix composite material product shell, an insert with the same protruding step as the fractured boss is designed and machined; a clamping block is machined on the middle of the back of the imitation boss of the insert corresponding to the second-order clamping groove, and a positioning pin hole B and a mounting counterbore B are respectively machined on both sides of the imitation boss corresponding to the positioning pin hole A and the mounting threaded hole A of the first-order clamping groove; S3. Machining of the positioning pin: A special positioning pin is machined corresponding to the positioning pin holes on the repair groove and the insert; S4. Installation and fixation of the insert: The clamping block of the insert is clamped into the second-order clamping groove of the repair groove. At this time, the imitation boss is clamped with the first-order clamping groove; then the positioning pin is inserted into the positioning pin hole A and the positioning pin hole B for fixation; the countersunk head screw is inserted into the mounting threaded hole A and the mounting counterbore B, and is screwed and tightened.

[0012] Further preferably, in S4, bonding glue is applied to the contact surface of the insert block and the repair groove before installation. Before installing the positioning pin, anaerobic glue is applied to the outer periphery of the positioning pin and cured for [X] hours after application. Sealing glue is applied to the countersunk screw before installation and cured for 24 hours after being fastened in place.

[0013] The present invention provides a repair structure and method for the fracture of the boss of the SiC aluminum matrix composite material product shell, which can be summarized as a repair method of "groove + insert block". Compared with the prior art, the present invention has the following beneficial technical effects: 1) The "groove + insert block" abandons the traditional welding method and adopts the insert block connection method, which improves the overall accuracy of the product after repair and is convenient for replacement and maintenance.

[0014] 2) Modular design: Through the modular design of the insert block and the groove, the insert block can be flexibly combined according to actual needs, improving the flexibility and adaptability of the design. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It shows the schematic diagram of the structure of the SiC aluminum matrix composite material product shell.

[0017] Figure 2 It shows the macroscopic morphology of the fractured boss and the crack propagation direction diagram.

[0018] Figure 3 It shows the microscopic diagram of the crack source and crack propagation direction of the boss.

[0019] From Figure 2 and Figure 3 it can be seen that: the crack of the fractured block originated from the back of the bottom of the drilled hole, and then extended upward and to the left and right, eventually resulting in the fracture of the boss.

[0020] Figure 4 It shows the schematic diagram of the front structure of the repair groove.

[0021] Figure 5 It shows the schematic diagram of the cross-section of the repair groove.

[0022] Figure 6 It shows the schematic diagram of the front structure of the insert block.

[0023] Figure 7 It shows the schematic diagram of the cross-section of the insert block.

[0024] Figure 8 It shows the schematic diagram of the groove-insert block assembly structure.

[0025] Among them, 1 - repair groove, 11 - first - order card slot, 12 - positioning pin hole A, 13 - installation threaded hole A, 14 - second - order card slot; 2 - insert block, 21 - imitation boss; 22 - positioning pin hole B, 23 - installation counterbore B, 24 - clamping block, 3 - positioning pin, 4 - countersunk head screw, 5 - SiC aluminum matrix composite product housing. Specific implementation manner

[0026] In order to more clearly understand the above - mentioned objects, features, and advantages of the present invention, the solution of the present invention will be further described below. It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0027] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings. Embodiment

[0028] Please refer to Figures 1 to 8 , the present invention provides a repair structure for the fracture of the boss of the SiC aluminum matrix composite product housing, including the SiC aluminum matrix composite product housing 5. A repair groove 1 is processed in the fracture area of the boss of the SiC aluminum matrix composite product housing 5, and an insert block 2 with an imitation boss 21 is assembled in the repair groove 1. The repair groove 1 includes a first - order card slot 11, and a second - order card slot 14 is processed in the middle of the first - order card slot 11; positioning pin holes A12 and installation threaded holes A13 are respectively processed in the two side areas of the first - order card slot 11. In the middle of the back of the imitation boss 21 of the insert block 2, a clamping block 24 is processed corresponding to the second - order card slot 14, and positioning pin holes B22 and installation counterbores B23 are respectively processed in the two side areas of the imitation boss 21 corresponding to the positioning pin hole A12 and the installation threaded hole A13 of the first - order card slot 11. A positioning pin 3 is inserted into the positioning pin hole A12 and the positioning pin hole B22 to ensure reliable positioning and higher precision of the insert block 2; a countersunk head screw 4 is screwed into the installation threaded hole A13 and the installation counterbore B23.

[0029] As Figures 1 to 3 shown, the insert block 2 is made of SiC aluminum matrix composite material.

[0030] As Figures 4 to 8 shown, the first - order card slot 11 and the second - order card slot 14 of the repair groove 1 and the imitation boss 21 and the clamping block 24 of the insert block 2 are bonded by epoxy glue.

[0031] As Figure 8 shown, anaerobic glue is coated on the positioning pin 3; sealant is coated on the countersunk head screw 4.

[0032] As Figures 4 to 5As shown, the installation threaded hole A13 is close to the second-order card slot 14 and is symmetrically arranged on both sides of the second-order card slot 14; the positioning pin hole A12 is far from the second-order card slot 14 and is symmetrically arranged on both sides of the second-order card slot 14.

[0033] In the present invention, the insert block 2 and the repair groove 1 are fixed by "screw + concave-convex fit + glue" in three ways. The first-order card slot 11 prevents the insert block 2 from rotating circumferentially, and the second-order card slot 14 strengthens and prevents axial rotation; being fixed by the positioning pin 3 and the countersunk head screw 4 ensures a firm and reliable radial position. Embodiment

[0034] Please refer to Figures 1 to 8 , this embodiment provides a repair method for the fracture of the boss of the SiC aluminum matrix composite material product shell. Based on the repair structure for the fracture of the boss of the SiC aluminum matrix composite material product in Embodiment 1, it includes the following steps: S1. Groove machining: At the fractured boss of the SiC aluminum matrix composite material product shell 5, machine the repair groove 1; the repair groove 1 includes a first-order card slot 11, and a second-order card slot 14 is machined in the middle of the first-order card slot 11; positioning pin holes A12 and installation threaded holes A13 are respectively machined in the two side areas of the first-order card slot 11; S2. Design and machining of the insert block: According to the boss structure of the SiC aluminum matrix composite material product shell 5, design and machine an insert block 2 with the same protruding step as the fractured boss; a clamping block 24 is machined corresponding to the second-order card slot 14 in the middle of the back of the imitation boss 21 of the insert block 2, and positioning pin holes B22 and installation countersunk head holes B23 are respectively machined corresponding to the positioning pin hole A12 and the installation threaded hole A13 in the two side areas of the imitation boss 21; S3. Machining the positioning pin: Machine a special positioning pin 3 corresponding to the positioning pin holes on the repair groove 1 and the insert block 2; S4. Installation and fixation of the insert block: Snap the clamping block 24 of the insert block 2 into the second-order card slot 14 of the repair groove 1. At this time, the imitation boss 21 is snapped into the first-order card slot 11; then insert the positioning pin 3 into the positioning pin hole A12 and the positioning pin hole B22 for fixation; insert the countersunk head screw 4 into the installation threaded hole A13 and the installation countersunk head hole B23 and tighten it.

[0035] Please refer to Figures 4 to 8 , in S4, before installation, apply adhesive to the contact surface between the insert block 2 and the repair groove 1; when installing the positioning pin 3, apply anaerobic adhesive to the outer circumference of the positioning pin 3 and cure for 4 hours after application; apply sealant before installing the countersunk head screw 4 and cure for 24 hours after tightening in place.

[0036] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Although the foregoing embodiments have been described in detail, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A repair structure for the fracture of the boss of the SiC aluminum matrix composite product shell, characterized in that, It includes an SiC aluminum matrix composite product housing (5). A repair groove (1) is machined in the boss fracture area of the SiC aluminum matrix composite product housing (5). A insert block (2) with an imitation boss (21) is assembled in the repair groove (1): The repair groove (1) includes a first-order card slot (11), and a second-order card slot (14) is machined in the middle of the first-order card slot (11); positioning pin holes A (12) and mounting threaded holes A (13) are respectively machined in the two side areas of the first-order card slot (11); In the middle of the back of the imitation boss (21) of the insert block (2), a clamping block (24) is machined corresponding to the second-order card slot (14). Positioning pin holes B (22) and mounting counterbore holes B (23) are respectively machined in the two side areas of the imitation boss (21) corresponding to the positioning pin hole A (12) and the mounting threaded hole A (13) of the first-order card slot (11); A positioning pin (3) is inserted into the positioning pin hole A (12) and the positioning pin hole B (22); A countersunk head screw (4) is screwed into the mounting threaded hole A (13) and the mounting counterbore hole B (23).

2. The repair structure for the fracture of the boss of the SiC aluminum matrix composite product housing according to claim 1, characterized in that, The insert block (2) is made of SiC aluminum matrix composite material.

3. The repair structure for the fracture of the boss of the SiC aluminum matrix composite material product housing according to claim 1, characterized in that, The first-order card slot (11) and the second-order card slot (14) of the repair groove (1) and the imitation boss (21) and the clamping block (24) of the insert block (2) are bonded by epoxy glue.

4. A repair structure for the fracture of the boss of the SiC aluminum matrix composite product housing according to claim 1, characterized in that, Anaerobic glue is coated on the positioning pin (3).

5. The repair structure for the fracture of the boss of the SiC aluminum matrix composite product housing according to claim 1, characterized in that, Sealant is coated on the countersunk head screw (4).

6. The repair structure for the fracture of the boss of the SiC aluminum matrix composite product housing according to claim 1, wherein, The mounting threaded hole A (13) is close to the second-order card slot (14) and is symmetrically arranged on both sides of the second-order card slot (14); the positioning pin hole A (12) is far from the second-order card slot (14) and is symmetrically arranged on both sides of the second-order card slot (14).

7. A repair method for the fracture of the boss of the SiC aluminum matrix composite product shell, characterized in that, Based on the repair structure for the fracture of the boss of the SiC aluminum matrix composite product housing according to any one of claims 1-6, it includes the following steps: S1. Groove machining: At the fractured boss of the SiC aluminum matrix composite product housing (5), a repair groove (1) is machined; the repair groove (1) includes a first-order card slot (11), and a second-order card slot (14) is machined in the middle of the first-order card slot (11); positioning pin holes A (12) and mounting threaded holes A (13) are respectively machined in the two side areas of the first-order card slot (11); S2. Design and machining of the insert block: According to the boss structure of the SiC aluminum matrix composite product housing (5), an insert block (2) with the same protruding step as the fractured boss is designed and machined; in the middle of the back of the imitation boss (21) of the insert block (2), a clamping block (24) is machined corresponding to the second-order card slot (14). Positioning pin holes B (22) and mounting counterbore holes B (23) are respectively machined in the two side areas of the imitation boss (21) corresponding to the positioning pin hole A (12) and the mounting threaded hole A (13) of the first-order card slot (11); S3. Machining of the positioning pin: Corresponding to the positioning pin holes on the repair groove (1) and the insert block (2), a special positioning pin (3) is machined; S4. Insert block installation and fixation: Snap the clamping block (24) of the insert block (2) into the second-order clamping groove (14) of the repair groove (1). At this time, the imitation boss (21) engages with the first-order clamping groove (11). Then insert the positioning pin (3) into the positioning pin hole A (12) and the positioning pin hole B (22) for fixation. Insert the countersunk head screw (4) into the installation threaded hole A (13) and the installation countersunk head hole B (23), and then screw it tightly.

8. A repair method for the fracture of the boss of the SiC aluminum matrix composite product housing according to claim 7, characterized in that, In S4, apply adhesive to the contact surface between the insert block (2) and the repair groove (1) before installation.

9. The repair method for the fracture of the boss of the SiC aluminum matrix composite product shell according to claim 7, characterized in that, In S4, apply anaerobic adhesive to the outer periphery of the positioning pin (3) before installing the positioning pin (3), and cure it for 4 hours after application.

10. A repair method for the fracture of the boss of the SiC aluminum matrix composite product shell according to claim 7, characterized in that, In S4, apply sealant to the countersunk head screw (4) before installation, and cure it for 24 hours after tightening it in place.

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