Hole extrusion strengthening device and method

Abstract

The invention relates to the technical field of hole cold extrusion strengthening processing, and discloses a hole extrusion strengthening device and method.Before a sample with a hole is installed, a supporting rod is axially moved to a first position so that the sample with the hole can be conveniently installed; after the perforated sample is installed and before the to-be-strengthened hole of the perforated sample is extruded and strengthened, the supporting rod is axially moved to the second position, so that the slotted core rod is conveniently controlled to pull out the perforated sample at a constant speed, and the to-be-strengthened hole is extruded and strengthened in the process that the slotted core rod is pulled out of the perforated sample at the constant speed. When the hole extrusion strengthening device is used for carrying out extrusion strengthening on a to-be-strengthened hole, as long as the supporting rod and the slotting core rod are not damaged and can be used, the supporting rod does not need to be disassembled, and only the supporting rod needs to be controlled to axially move in the slotting core rod, so that the supporting rod can be arranged at a first position where a sample with a hole can be mounted; and the second position can be switched for extruding and strengthening the to-be-strengthened hole, so that the extruding and strengthening efficiency of the slotted core rod hole is improved.

Description

Technical Field

[0001] The invention relates to the technical field of hole cold extrusion strengthening processing, and in particular to a hole extrusion strengthening device and method. Background Art

[0002] Rivet connection and threaded connection are commonly used connection methods on aircraft, so there are many connection holes for rivet connection and threaded connection on aircraft. The existence of connection holes will lead to material discontinuity and easily produce stress concentration. When the hole structure is subjected to external alternating loads, fatigue cracks are prone to occur, increasing the fatigue crack growth rate, thereby reducing the service life of the hole structure. Therefore, extrusion is often used to strengthen the fatigue strength of the hole, and slit bushing and solid mandrel hole extrusion strengthening are currently the most widely used anti-fatigue strengthening technologies in the aviation field.

[0003] Specifically, the slotted bushing is placed in the sample with a hole, and the extrusion mandrel is moved to extrude the slotted bushing, and the slotted bushing elastically deforms to extrude and strengthen the sample hole wall, thereby completing the hole extrusion strengthening of the sample with a hole. However, the following defects exist in the process of hole extrusion strengthening using the slotted bushing: (1) Since the slotted bushing is placed in the sample with a hole, the bushing wall thickness of the slotted bushing is thin, and the slotted bushing is easily deformed by the extrusion mandrel, resulting in that the slotted bushing cannot be used for multiple hole extrusion strengthening after being used once, thereby increasing the cost of the slotted bushing hole extrusion strengthening process. (2) The working ring diameter of the solid mandrel is larger than that of the sample with a hole, resulting in that the sample with a hole must be installed from the connecting section of the solid mandrel. For samples with a hole that are large in size and thickness, it is more difficult to install the sample with a hole, which leads to limitations in the solid mandrel hole extrusion strengthening process.

[0004] In order to solve the problems existing in the process of extrusion strengthening of slotted bushings and solid mandrel holes, the researchers proposed a slotted mandrel hole extrusion strengthening technology, which specifically includes the following steps:

[0005] (1) Before cold extrusion strengthening of the hole to be strengthened of the perforated sample, the front of the slotted mandrel passes through the auxiliary plate and the hole to be strengthened on the perforated sample; the auxiliary plate is placed in front of the perforated sample, and the hole of the auxiliary plate has the same diameter and is coaxial with the hole to be strengthened of the perforated sample; a slit is provided on the slotted mandrel, so that the position of the working ring of the slotted mandrel can be contracted at this time, and the hole to be strengthened of the perforated sample is not extruded and strengthened;

[0006] (2) Insert a support rod into the slotted mandrel. Due to the presence of the support rod, the position of the working ring of the slotted mandrel cannot be contracted, and its diameter is larger than the diameter of the hole to be strengthened of the perforated sample. During the process of pulling the slotted mandrel inserted with the support rod out of the hole to be strengthened of the perforated sample at a uniform speed, the working ring of the slotted mandrel squeezes the hole wall to be strengthened, causing the hole wall of the hole to be strengthened of the perforated sample to undergo elastic-plastic deformation, thereby achieving a strengthening effect.

[0007] The above-mentioned slotted mandrel hole extrusion strengthening technology has the following defects: after using the slotted mandrel to extrude and strengthen a hole to be strengthened, the support rod needs to be removed before the next hole to be strengthened can be passed through the working ring, and then the support rod needs to be installed again before the slotted mandrel can be used to extrude and strengthen the hole to be strengthened. The support rod needs to be frequently disassembled and assembled, which seriously affects the extrusion strengthening efficiency of the slotted mandrel hole. Summary of the invention

[0008] The object of the present invention is to provide a hole extrusion strengthening device and method, which does not require frequent disassembly and assembly of support rods, so as to improve the extrusion strengthening efficiency of slotted core rod holes.

[0009] To achieve this object, on the one hand, the present invention adopts the following technical solutions:

[0010] A hole extrusion strengthening device comprises a slotted mandrel and a support rod, wherein the slotted mandrel is axially movable and is provided with an axially extending through hole, wherein one axial end of the slotted mandrel forms a working portion, wherein the working portion is provided with at least two deformation slits spaced apart along the circumference of the slotted mandrel, wherein the deformation slit passes through the inner and outer peripheral walls of the through hole and one end of the deformation slit extends to the end face of the working portion; wherein the slotted mandrel between two adjacent deformation slits forms a deformation portion, wherein the deformation portion comprises a deformation body and an extrusion strengthening circular ring segment fixed to the outer peripheral wall of the deformation body, wherein all the extrusion strengthening circular ring segments are located on the same working circular ring;

[0011] The penetration hole includes a deformation hole surrounded by a plurality of deformation parts, and an avoidance hole located at one axial end of the deformation hole; one end of the support rod is penetrated through the avoidance hole, and the support rod can slide axially so that the other end of the support rod can move back and forth between the first position and the second position;

[0012] When the support rod is located at the first position, the support rod exits the deformation hole, and when the support rod is located at the second position, the support rod passes through the deformation hole.

[0013] As a preferred technical solution of the above-mentioned hole extrusion strengthening device, the slit core rod includes a clamping and fixing section, and a guide section connected to the working part and the clamping and fixing section, one of the inner circumferential wall of the guide section and the outer circumferential wall of the support rod is provided with a guide groove, and the other is provided with a guide protrusion, and the guide protrusion is slidably arranged in the guide groove along the axial direction of the slit core rod.

[0014] As a preferred technical solution of the above-mentioned hole extrusion strengthening device, the guide groove has two sliding side walls arranged opposite to each other along the circumference of the guide section, one of the sliding side walls is provided with a limiting groove, and the support rod located at the second position can rotate circumferentially relative to the slotted mandrel, so that the guide protrusion moves in and out of the limiting groove along the circumference of the slotted mandrel;

[0015] The support rod is located at the second position, and the guide protrusion is located in the limiting groove so that the support rod is limited to slide axially relative to the slotted core rod.

[0016] As a preferred technical solution of the above-mentioned hole extrusion strengthening device, the guide groove is arranged in the guide section and passes through the inner and outer circumferential walls of the guide section, and one end of the guide protrusion passes through the guide groove to form a handle portion.

[0017] As a preferred technical solution of the above-mentioned hole extrusion strengthening device, the guide protrusion is detachably connected to the support rod.

[0018] As a preferred technical solution of the above-mentioned hole extrusion strengthening device, the deformable body includes a first working section and a second working section, the first working section is connected to the guide section through the second working section, the outer peripheral walls of the first working section and the second working section are both conical surfaces, and along the direction from the first working section to the second working section, the outer diameter of the first working section gradually increases, and the outer diameter of the second working section gradually decreases, and the extrusion strengthening annular section is located at the connecting position of the first working section and the second working section.

[0019] As a preferred technical solution of the above-mentioned hole extrusion strengthening device, the length of the support rod is L1, the length of the slotted core rod is L2, and the ratio of L1 to L2 is in the range of 0.4-0.6.

[0020] As a preferred technical solution of the above-mentioned hole extrusion strengthening device, a stop hole is provided at one end of the deformation seam away from the axial end surface of the working part.

[0021] As a preferred technical solution of the above-mentioned hole extrusion strengthening device, the penetration hole is set to penetrate along the axial direction of the slotted core rod.

[0022] In order to achieve the above object, on the other hand, the present invention further provides a hole extrusion strengthening method, using the hole extrusion strengthening device as described in any of the above schemes, the hole extrusion strengthening method comprises the following steps:

[0023] The support rod is axially moved to a first position, and the deformation portion is radially pressed in a direction close to the central axis of the slotted mandrel so that the outer diameter of the working ring is smaller than the hole diameter of the hole to be strengthened of the holed specimen;

[0024] Install the specimen with holes;

[0025] The support rod is axially moved to a second position, so that the support rod supports the deformed portion, and the outer diameter of the working ring is larger than the hole diameter of the hole to be strengthened of the sample with a hole;

[0026] Control the slotted core rod equipped with a support rod to pull out the holed specimen at a uniform speed.

[0027] Beneficial effects of the present invention: The hole extrusion strengthening device and method provided by the present invention, before installing the sample with a hole, moves the support rod axially to the first position, at which time the support rod has no supporting effect on the deformation part, and radially presses the deformation part in the direction close to the central axis of the slotted core rod, so that the outer diameter of the working ring is smaller than the aperture of the hole to be strengthened of the sample with a hole, which is convenient for installing the sample with a hole, and the hole wall of the hole to be strengthened on the sample with a hole will not be extruded and strengthened during the installation of the sample with a hole. After completing the installation of the sample with a hole and before extruding and strengthening the hole to be strengthened, the support rod is axially moved to the second position, at which time the support rod has a supporting effect on the deformation part, so that when the working ring is subjected to radial force, the deformation seam will not shrink, and the diameter of the working ring is larger than the aperture of the hole to be strengthened. Afterwards, the slit mandrel is controlled to pull out the hole sample at a uniform speed, and the support rod and the slit mandrel move synchronously. Since the diameter of the working ring is larger than the aperture of the hole to be strengthened, in the process of clamping the slit mandrel on the hole sample, the working ring on the slit mandrel will squeeze the hole wall of the hole sample, and the hole wall of the hole sample will undergo elastic-plastic deformation, so that a beneficial residual compressive stress field is formed on the hole wall, thereby realizing the hole extrusion strengthening of the hole sample.

[0028] When the hole extrusion strengthening device is used to extrude and strengthen the hole to be strengthened, as long as the support rod and the slit core rod are both intact and can be used, there is no need to disassemble the support rod. It is only necessary to control the axial movement of the support rod in the slit core rod to achieve the switching of the support rod between a first position for installing a sample with a hole and a second position for extrusion and strengthening the hole to be strengthened, thereby improving the extrusion strengthening efficiency of the slit core rod hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0030] Figure 1 is a structural schematic diagram of a hole extrusion strengthening device provided by an embodiment of the present invention when the support rod is located at the second position;

[0031] Figure 2is a structural schematic diagram of a hole extrusion strengthening device provided by an embodiment of the present invention when the support rod is located at a first position;

[0032] Figure 3 is a schematic structural diagram of a support rod provided by an embodiment of the present invention;

[0033] Figure 4 yes Figure 1 A local enlarged schematic diagram of the middle A;

[0034] Figure 5 is a schematic diagram of a first installation process of a support rod provided by an embodiment of the present invention;

[0035] Figure 6 is a schematic diagram of a second installation process of a support rod provided by an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of a first installation process of a holed specimen provided by an embodiment of the present invention;

[0037] Figure 8 is a schematic diagram of a second installation process of a perforated specimen provided by an embodiment of the present invention;

[0038] Fig. 9 This is a process diagram of extruding and strengthening a hole to be strengthened using the hole extrusion strengthening device provided by an embodiment of the present invention.

[0039] In the figure:

[0040] 1. Slit mandrel; 11. Working part; 12. Guide section; 13. Clamping and fixing section; 14. Deformation slit; 15. Deformation part; 151. First working section; 152. Second working section; 153. Extrusion strengthening annular section; 16. Guide groove; 17. Limiting groove; 18. Stop hole;

[0041] 2. Support rod; 21. Threaded mounting hole;

[0042] 3. Guide convex part;

[0043] 100. Specimen with holes; 101. Hole to be strengthened. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0045] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0047] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0048] like Figures 1 to 8 As shown, an embodiment of the present invention provides a hole extrusion strengthening device, including a slotted mandrel 1, a working ring and a support rod 2, wherein the slotted mandrel 1 can move axially and is provided with an axially extending through hole, an axial end of the slotted mandrel 1 forms a working portion 11, and the working portion 11 is provided with at least two deformation slits 14 distributed circumferentially along the slotted mandrel 1, and the deformation slit 14 passes through the inner and outer circumferential walls of the through hole and one end extends to the end face of the working portion 11; the slotted mandrel 1 between two adjacent deformation slits 14 forms a deformation portion 15, and the deformation portion 15 includes a deformation body and an extrusion strengthening circular ring segment 153 fixed to the outer circumferential wall of the deformation body, all the extrusion strengthening circular ring segments 153 are located on the same working circular ring, and the through hole includes a deformation hole surrounded by a plurality of deformation portions 15, and an avoidance hole located at one axial end of the deformation hole. One end of the support rod 2 is passed through the avoidance hole, and the support rod 2 can slide axially so that the other end of the support rod 2 can move back and forth between the first position and the second position. When the support rod 2 is in the first position, the support rod 2 exits the deformation hole, and when the support rod 2 is in the second position, the support rod 2 passes through the deformation hole.

[0049] The perforated sample 100 is provided with a hole 101 to be strengthened. When the support rod 2 is in the first position, the diameter of the working ring is smaller than the aperture of the hole 101 to be strengthened; when the support rod 2 is in the second position, the diameter of the working ring is larger than the aperture of the hole 101 to be strengthened.

[0050] Slide the support rod 2 to the first position of exiting the deformation hole. Due to the existence of the deformation slit 14, the outer peripheral wall of the deformation part 15 is pressed at this time, and the deformation part 15 will deform and shrink inward, so that the outer diameter of the working ring is reduced. The holed sample 100 is installed from the working part 11 so that the working part 11 passes through the hole 101 to be strengthened, and the holed sample 100 is fixed. Slide the support rod 2 to the second position of passing through the deformation hole. At this time, the inner peripheral wall of the deformation hole is squeezed by the support rod 2, so that the deformation part 15 cannot shrink inward when squeezing the deformation part 15 inward, and the outer diameter of the working ring remains unchanged. Then, the slotted mandrel 1 is controlled to move in the direction from the second position to the first position, and the working ring squeezes and strengthens the hole wall of the hole 101 to be strengthened. The hole wall of the hole 101 to be strengthened undergoes elastic-plastic deformation, so that the hole wall forms a beneficial residual compressive stress field, thereby achieving extrusion strengthening of the hole 101 to be strengthened.

[0051] When the hole extrusion strengthening device is used to extrude and strengthen the hole 101 to be strengthened, as long as the support rod 2 and the slit core rod 1 are both intact and can be used, there is no need to disassemble the support rod 2. It is only necessary to control the axial movement of the support rod 2 in the slit core rod 1 to achieve the switching of the support rod 2 between the first position in which the hole sample 100 can be installed and the second position in which the hole 101 to be strengthened can be extruded and strengthened, thereby improving the hole extrusion strengthening efficiency of the slit core rod 1.

[0052] Exemplarily, four deformable slits 14 are provided, and four deformable portions 15 are correspondingly formed. It should be noted that the number of the deformable slits 14 may also be 2, 3, 5 or more, which is not limited here.

[0053] In some embodiments, the slotted mandrel 1 includes a clamping and fixing section 13, and a guide section 12 connected to the working section 11 and the clamping and fixing section 13. A guide groove 16 is provided on one of the inner peripheral wall of the guide section 12 and the outer peripheral wall of the support rod 2, and a guide convex portion 3 is provided on the other. The guide convex portion 3 is slidably arranged in the guide groove 16 along the axial direction of the slotted mandrel 1. The clamping and fixing section 13 is used to fix the slotted mandrel 1 on the hole extrusion strengthening fixture, and the movement of the support rod 2 is guided by the cooperation of the guide groove 16 and the guide convex portion 3 to improve the stability of the support rod 2 during the movement process. The moving distance of the support rod 2 can also be limited to prevent the support rod 2 from escaping from the slotted mandrel 1. Exemplarily, the guide convex portion 3 is convexly arranged on the outer peripheral wall of the support rod 2, and the guide groove 16 is opened in the guide section 12. In other embodiments, the guide convex portion 3 can also be convexly arranged on the inner peripheral wall of the guide section 12, and the guide groove 16 is opened on the outer peripheral wall of the support rod 2.

[0054] In some embodiments, the guide groove 16 has two sliding side walls arranged relatively to each other along the circumference of the guide section 12, and a limiting groove 17 is provided on one of the sliding side walls. The support rod 2 located at the second position can rotate circumferentially relative to the slit mandrel 1 so that the guide protrusion 3 can enter and exit the limiting groove 17 along the circumference of the slit mandrel 1; when the support rod 2 is located at the second position, the guide protrusion 3 is located in the limiting groove 17 to limit the axial sliding of the support rod 2 relative to the slit mandrel 1.

[0055] Specifically, after the support rod 2 is axially moved to the second position, the support rod 2 is controlled to rotate circumferentially so that the guide protrusion 3 enters the limiting groove 17 to limit the axial sliding of the support rod 2 relative to the slotted mandrel 1. After completing one extrusion strengthening, the support rod 2 is controlled to rotate circumferentially in the reverse direction so that the guide protrusion 3 exits the limiting groove 17, and then the support rod 2 is controlled to move axially in the reverse direction to the first position, so as to facilitate the installation of the next perforated sample 100 on the working part 11.

[0056] By limiting the axial sliding of the support rod 2 relative to the slit core rod 1, the support rod 2 can be prevented from moving during the extrusion strengthening of the hole 101 to be strengthened, ensuring that the outer diameter of the working ring remains unchanged during the extrusion strengthening of the hole 101 to be strengthened, thereby improving the pore size uniformity of the perforated sample 100 after extrusion strengthening.

[0057] In some embodiments, the guide groove 16 is provided in the guide section 12 and penetrates the inner and outer peripheral walls of the guide section 12, and one end of the guide protrusion 3 passes through the guide groove 16 to form a handle. With such a configuration, the support rod 2 can be pushed and pulled axially by holding the handle, so that the support rod 2 can be switched between the first position and the second position. The support rod 2 can also be driven to rotate by holding the handle so that the guide protrusion 3 enters and exits the limit groove 17, and the support rod 2 can be moved conveniently and quickly.

[0058] Optionally, the guide protrusion 3 is detachably connected to the support rod 2. Exemplarily, a threaded mounting hole 21 is provided on the outer peripheral wall of the support rod 2, one end of the guide protrusion 3 passes through the guide groove 16 and is threadedly connected to the threaded mounting hole 21, and the other end of the guide protrusion 3 extends out of the guide groove 16 to form a handle.

[0059] Before inserting the support rod 2 into the slotted mandrel 1, the guide protrusion 3 can be removed to prevent the guide protrusion 3 from interfering with the insertion of the support rod 2 into the slotted mandrel 1. After that, the support rod 2 can be rotated so that the threaded mounting hole 21 faces the guide groove 16, and one end of the guide protrusion 3 is passed through the guide groove 16 and connected to the support rod 2.

[0060] In other embodiments, the guide protrusion 3 can also be connected to the support rod 2 in other ways, such as providing a mounting groove on the outer peripheral wall of the support rod 2, providing a spring on the inner wall of the mounting groove, and connecting the two ends of the spring to the support rod 2 and the guide protrusion 3 respectively. One end of the guide protrusion 3 is inserted into the mounting groove by sliding along the radial direction of the support rod 2, and the other end of the guide protrusion 3 can enter and exit the mounting groove. Before inserting the support rod 2 into the slotted core rod 1, the guide protrusion 3 is pressed along the radial direction of the support rod 2 so that the guide protrusion 3 enters the mounting groove, the spring is compressed, and then the support rod 2 is controlled to move axially to enter the slotted core rod 1. After the support rod 2 moves axially to the second position, the inner peripheral wall of the slotted core rod 1 is lost, and the spring reset will cause one end of the spring to pass through the guide groove 16 to form a handle.

[0061] In other embodiments, the support rod 2 may be provided with a driving member, which controls the axial movement and circumferential rotation of the support rod 2 to achieve automatic movement of the support rod 2, thereby improving the degree of automation of the hole extrusion strengthening device and further improving the hole extrusion strengthening efficiency.

[0062] In some embodiments, the clamping and fixing section 13 is threadedly connected to the guide section 12. The hole extrusion strengthening device also includes a linear drive unit, such as a cylinder, an electric push rod, etc. The output end of the linear drive unit is connected to the clamping and fixing section 13, and the linear drive unit is used to control the axial movement of the support rod 2 to achieve extrusion strengthening of the hole 101 to be strengthened by using the working ring.

[0063] In some embodiments, the deformation body includes a first working section 151 and a second working section 152. The first working section 151 is connected to the guide section 12 through the second working section 152. The outer peripheral walls of the first working section 151 and the second working section 152 are both conical surfaces, and along the direction from the first working section 151 to the second working section 152, the outer diameter of the first working section 151 gradually increases, and the outer diameter of the second working section 152 gradually decreases. The extrusion strengthening annular section 153 is located at the connection position of the first working section 151 and the second working section 152.

[0064] The extrusion strengthening circular ring segment 153 is arranged at the connecting position of the first working segment 151 and the second working segment 152, so that the outer diameter of the extrusion strengthening circular ring segment 153 is larger than the outer diameter of the first working segment 151 and larger than the outer diameter of the second working segment 152, so as to avoid the first working segment 151 and the second working segment 152 on both sides of the extrusion strengthening circular ring segment 153 affecting the extrusion strengthening work of the extrusion strengthening circular ring segment 153 on the hole 101 to be strengthened.

[0065] If the length of the support rod 2 is not much different from that of the slotted mandrel 1, it will cause the support rod 2 to be difficult to move in the slotted mandrel 1. If the length of the support rod 2 is less than the length of the slotted mandrel 1 and the difference is too large, it will cause the support rod 2 to extend too long from the slotted mandrel 1 when the support rod 2 moves back and forth, increasing the overall length of the slotted mandrel 1 and the length of the slotted mandrel 1 required to be clamped by the hole extrusion strengthening fixture. In some embodiments, the length of the support rod 2 is L1, the length of the slotted mandrel 1 is L2, and the ratio of L1 to L2 is in the range of 0.4-0.6. Exemplarily, L1:L2=0.5.

[0066] In some embodiments, a wrinkle-stopping hole 18 is provided at one end of the deformation slit 14 away from the axial end surface of the working portion 11. By providing the wrinkle-stopping hole 18, the service life of the slotted mandrel 1 can be prevented from being affected by the deformation slit 14 being treated as a crack.

[0067] In some embodiments, the penetration hole is set to penetrate the slit mandrel 1 axially, so that the penetration hole is a through hole, and the slit mandrel 1 is an axially penetrated hollow structure.

[0068] There are two ways to install the support rod 2, such as Figure 5 The first installation method shown is: insert the support rod 2 into the slotted mandrel 1 from the end where the clamping and fixing section 13 of the slotted mandrel 1 is located, and then pass one end of the guide protrusion 3 through the guide groove 16 and connect it to the support rod 2. Figure 6 The second installation method shown is: insert the support rod 2 into the slotted core rod 1 from the end where the working portion 11 of the slotted core rod 1 is located, and then pass one end of the guide protrusion 3 through the guide groove 16 and connect it to the support rod 2.

[0069] The two installation methods of the support rod 2 mentioned above can both install the support rod 2 in the slotted core rod 1 .

[0070] When the perforated sample 100 is installed on the slotted mandrel 1, there are two ways of installing it.

[0071] like Figure 7 The first installation method shown is: there is no support rod 2 in the slotted mandrel 1. At this time, an external force is applied to the working part 11 of the slotted mandrel 1 to shrink the deformation slot 14 of the working part 11, so that the outer diameter of the working ring is smaller than the hole diameter of the hole 101 to be strengthened. Then, the holed sample 100 is installed from the working part 11 and the holed sample 100 is sleeved outside the guide section 12 of the slotted mandrel 1. During the installation of the holed sample 100, the working ring of the slotted mandrel 1 will not squeeze and strengthen the hole wall of the holed sample 100. Then, the above-mentioned method is adopted. Figure 6 The second supporting rod 2 installation method shown is sufficient to install the supporting rod 2 , and the installation of the supporting rod 2 will not affect the perforated sample 100 .

[0072] like Figure 8 In the second installation method shown, there is a support rod 2 in the slit core rod 1. The support rod 2 is axially moved to the first position so that the support rod 2 is away from the working ring on the slit core rod 1. At this time, the support rod 2 does not support the working ring. By applying external force to the working part 11 of the slit core rod 1, the deformation seam 14 of the working part 11 is contracted, so that the outer diameter of the working ring is smaller than the aperture of the hole 101 to be strengthened. Then, the perforated sample 100 is installed from the working part 11, and the perforated sample 100 is sleeved outside the guide section 12 of the slit core rod 1.

[0073] Based on the above-mentioned hole extrusion strengthening device, an embodiment of the present invention further provides a hole extrusion strengthening method, which uses the above-mentioned hole extrusion strengthening device to perform extrusion strengthening on the hole 101 to be strengthened of the hole sample 100.

[0074] Fig. 9 : is a process diagram of the hole extrusion strengthening method, which includes the following steps:

[0075] S1, install support rod 2;

[0076] S2, installing the holed specimen 100;

[0077] S3, axially moving the support rod 2 to the second position, using the support rod 2 to support the working ring, so that when the working ring is subjected to radial force, the deformation gap 14 will not shrink, and the diameter of the working ring is larger than the aperture of the hole 101 to be strengthened;

[0078] S4. Control the slit mandrel 1 to pull out the perforated sample 100 at a uniform speed. The support rod 2 and the slit mandrel 1 move synchronously. Since the diameter of the working ring is larger than the aperture of the hole 101 to be strengthened, in the process of clamping the slit mandrel 1 on the perforated sample 100, the working ring on the slit mandrel 1 will squeeze the hole wall of the perforated sample 100, and the hole wall of the perforated sample 100 will undergo elastic-plastic deformation, so that a beneficial residual compressive stress field is formed on the hole wall, thereby achieving extrusion strengthening of the hole of the perforated sample 100.

[0079] S5. After completing the extrusion strengthening of a hole 101 to be strengthened in the hole test, control the support rod 2 to move axially to the first position, and install the hole sample 100 again.

[0080] In addition, the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A hole extrusion strengthening device, comprising a slotted mandrel (1) and a support rod (2), wherein the slotted mandrel (1) is axially movable and is provided with an axially extending through hole, wherein one axial end of the slotted mandrel (1) forms a working portion (11), wherein the working portion (11) is provided with at least two deformation slits (14) spaced apart along the circumference of the slotted mandrel (1), wherein the deformation slit (14) penetrates the inner and outer circumferential walls of the through hole and one end extends to the end face of the working portion (11); the slotted mandrel (1) between two adjacent deformation slits (14) forms a deformation portion (15), wherein the deformation portion (15) comprises a deformation body and an extrusion strengthening circular ring segment (153) fixed to the outer circumferential wall of the deformation body, wherein all the extrusion strengthening circular ring segments (153) are located on the same working circular ring; It is characterized in that The penetration hole comprises a deformation hole surrounded by a plurality of deformation parts (15), and an avoidance hole located at one axial end of the deformation hole; one end of the support rod (2) is penetrated through the avoidance hole, and the support rod (2) can slide axially so that the other end of the support rod (2) can move back and forth between the first position and the second position; When the support rod (2) is located at the first position, the support rod (2) exits the deformation hole; when the support rod (2) is located at the second position, the support rod (2) passes through the deformation hole.

2. The hole extrusion strengthening device according to claim 1, characterized in that: The slotted core rod (1) comprises a clamping and fixing section (13), and a guide section (12) connected to a working section (11) and the clamping and fixing section (13); a guide groove (16) is provided on one of an inner peripheral wall of the guide section (12) and an outer peripheral wall of the support rod (2); and a guide protrusion (3) is provided on the other; the guide protrusion (3) is slidably arranged in the guide groove (16) along the axial direction of the slotted core rod (1).

3. The hole extrusion strengthening device according to claim 2, characterized in that: The guide groove (16) has two sliding side walls arranged opposite to each other along the circumference of the guide section (12), one of the sliding side walls being provided with a limiting groove (17), and the support rod (2) located at the second position can rotate circumferentially relative to the slotted mandrel (1), so that the guide protrusion (3) can enter and exit the limiting groove (17) along the circumference of the slotted mandrel (1); The support rod (2) is located at the second position, and the guide protrusion (3) is located in the limiting groove (17) so as to limit the axial sliding of the support rod (2) relative to the slotted core rod (1).

4. The hole extrusion strengthening device according to claim 3, characterized in that: The guide groove (16) is arranged on the guide section (12) and penetrates the inner and outer peripheral walls of the guide section (12); one end of the guide protrusion (3) passes through the guide groove (16) to form a handle portion.

5. The hole extrusion strengthening device according to claim 4, characterized in that: The guide protrusion (3) is detachably connected to the support rod (2).

6. The hole extrusion strengthening device according to claim 2, characterized in that: The deformable body comprises a first working section (151) and a second working section (152); the first working section (151) is connected to the guide section (12) via the second working section (152); the outer peripheral walls of the first working section (151) and the second working section (152) are both conical surfaces; and along the direction from the first working section (151) to the second working section (152), the outer diameter of the first working section (151) gradually increases, while the outer diameter of the second working section (152) gradually decreases; the extrusion strengthening annular section (153) is located at the connecting position of the first working section (151) and the second working section (152).

7. The hole extrusion strengthening device according to any one of claims 1 to 6, characterized in that: The length of the support rod (2) is L1, the length of the slotted core rod (1) is L2, and the ratio of L1 to L2 is in the range of 0.4-0.

6.

8. The hole extrusion strengthening device according to any one of claims 1 to 6, characterized in that: A stop hole (18) is provided at one end of the deformation slit (14) away from the axial end surface of the working portion (11).

9. The hole extrusion strengthening device according to any one of claims 1 to 6, characterized in that: The penetration hole is arranged to penetrate along the axial direction of the slotted core rod (1).

10. A hole extrusion strengthening method, characterized in that: Using the hole extrusion strengthening device according to any one of claims 1 to 9, the hole extrusion strengthening method comprises the following steps: The support rod (2) is axially moved to a first position, and the deformation portion (15) is radially pressed in a direction close to the central axis of the slotted core rod (1) so that the outer diameter of the working ring is smaller than the hole diameter of the hole (101) to be strengthened of the hole sample (100); Installing a test specimen with a hole (100); The support rod (2) is axially moved to a second position, so that the support rod (2) supports the deformation portion (15), and the outer diameter of the working ring is larger than the hole diameter of the hole (101) to be strengthened of the hole sample (100); A slotted core rod (1) equipped with a support rod (2) is controlled to pull out a perforated sample (100) at a uniform speed.

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