Additive manufacturing cylindrical part surface tooth-shaped rolling strengthening and toughening equipment and process

Abstract

The invention discloses additive manufacturing cylindrical part surface tooth-shaped rolling strengthening and toughening equipment and process, the additive manufacturing cylindrical part surface tooth-shaped rolling strengthening and toughening equipment comprises a lower die holder, an upper die holder and a guide stand column, a rotating base is arranged in the lower die holder, a positioning assembly is arranged on the rotating base, an inner wall ultrasonic roller device is arranged on the bottom surface of the upper die holder, and an inner wall ultrasonic roller device is arranged on the bottom surface of the upper die holder. The inner wall ultrasonic roller device comprises an inner wall radial groove seat, an inner wall roller seat and an inner wall roller; outer wall ultrasonic roller devices are arranged on the two end sides of the inner wall ultrasonic roller device, each outer wall ultrasonic roller device comprises an outer wall radial groove seat, an outer wall roller seat and an outer wall roller, and ultrasonic vibration devices are arranged on the inner wall radial groove seats and the outer wall radial groove seats respectively. According to the method, gradient strengthening and toughening of the whole inner and outer wall tissue and performance can be achieved efficiently in a high-quality and high-degree-of-freedom mode, the problem that deep tissue modification is difficult to achieve on the basis that the structure of the cylindrical part is not changed is solved, the rolling strengthening process is stable, and the gradient change of the tissue is more remarkable.

Description

Technical Field

[0001] The invention belongs to the technical field of metal roll forming, and specifically relates to an additively manufactured cylindrical part surface toothed roll-forming strengthening and toughening device and process. Background Art

[0002] Aerospace is the key development direction of high-end equipment manufacturing industry. Aero-engine integral rings and space rocket compartments are core components in the aerospace field, and they have strict requirements on structure and service performance. The structural characteristics of these components are usually large size and complex geometry, and they often need to withstand extreme mechanical loads, temperature fluctuations and vibration environments. Service requirements include improved surface strength, fatigue resistance and corrosion resistance. In order to meet these performance requirements, the surface of the components usually needs to be strengthened, and the organizational structure needs to be optimized through appropriate heat treatment or plastic processing technology to ensure the reliability and stability of the components in long-term use. If large-scale integral precision components are made using traditional long-process processes, residual stress evolution and dimensional loss of control will occur due to phase change and thermal / mechanical coupling, resulting in shape degradation. In contrast, additive manufacturing (AM) technology has significant advantages, especially when facing complex shapes and large-size precision components.

[0003] However, workpieces manufactured by laser additive manufacturing are usually not directly usable, mainly because their surface organization and microstructure are difficult to fully meet the strict service requirements. First, rough melt track textures and tiny defects are easily formed on the surface during additive manufacturing. These defects are easy to become the starting point of fatigue cracks under cyclic stress, significantly reducing fatigue life. Secondly, the microstructure of additively manufactured parts is non-uniform. The surface grains may be fine but brittle, and there may be coarse columnar crystals or texture distribution inside, resulting in unsatisfactory performance gradients. However, components such as rocket cabins usually require strong surface and rich internal toughness, which requires a special toughening process to form a reasonable performance gradient. For large-scale complex parts manufactured by additive manufacturing, traditional toughening processes (such as heat treatment, cold processing or machining) face significant challenges in implementing their gradient toughening, especially without destroying the one-time molding structure. Heat treatment processes may cause deformation and stress redistribution of additively manufactured parts, destroying their precision and microstructure. Traditional machining methods also have difficulty achieving uniform plastic deformation on complex geometric shapes, and over-processing may cause surface defects or changes in grain structure, thus affecting the overall performance of the material. However, gradient strengthening is crucial for high-load structures such as rockets. By achieving gradient strengthening on the inner and outer surfaces of cylindrical parts, the grains can be refined on the surface to improve strength and fatigue resistance, while coarser grains are maintained inside to ensure toughness. This structural optimization can effectively cope with temperature changes, mechanical loads and dynamic impacts in extreme environments, and improve the reliability and service life of components. For a certain rocket compartment part, it needs to have high strength, fatigue resistance and lightweight in the service environment. The use of gradient strengthening design is an effective way to improve performance.

[0004] At present, the common metal surface deformation strengthening technologies include shot peening and surface rolling technology. The deformation hardening layer of shot peening is relatively thin, generally 0.15 ~ 1.5mm. Although it can adapt to complex shapes, it is mainly suitable for fatigue resistance. The multi-purpose surface rolling technology, which has a greater demand for the thickness of the modified layer, is a process in which a ball or roller rolls or extrude the surface of the processed part under a certain pressure to cause plastic deformation and form a strengthening layer. At present, a simple improvement or replacement of the rolling tool can be used for limited organization regulation, but it also has the limitations of surface rolling technology. It is only applicable to some simple-shaped flat parts and groove parts, etc., and cannot be applied to the surface of parts with complex shapes, such as cylindrical parts formed in one piece by additive manufacturing. Based on the demand for thicker gradient organization hardening, traditional toughening rolling requires a larger roller pressure to obtain a thicker deformation layer, but excessive roller pressure will cause uneven deformation of the metal surface, resulting in surface defects. Different metal materials also have different hardness and organizational structure. This phenomenon is particularly obvious for harder metals or additively manufactured components with uneven surface hardness. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a device and process for strengthening the surface of a cylindrical part by toothed rolling in additive manufacturing. The innovative process and equipment design scheme is adopted. By performing toothed rolling and flattening processes on the inner and outer surfaces of the cylinder wall, the surface material undergoes plastic deformation and accumulates plastic strain, thereby forming a structure with a gradient organization. In this process, the cylindrical part is fixed by the bottom mold and rotates about the central axis. The core components of the processing equipment include four helical rollers and cylindrical rollers, which are distributed in pairs on the inner and outer surfaces of both ends of the cylindrical part. The continuous rolling of the helical rollers can make the force on the cylinder wall have better continuity, and the two pairs of helical rollers rotate in opposite directions. Through the synchronous radial and axial feeding motions, a strengthening path with a double helix shape can be formed on the inner and outer wall surfaces, thereby forming a cross-shaped tooth mark different from the traditional wave shape. This tooth mark can provide more accumulated plastic strain in one pass, and the feed depth required when rolling flat is lower, thereby effectively reducing the deformation disadvantages of wall thinning and excessive elongation. Moreover, through this path design, not only can the entire surface of the cylinder wall be fully covered, but also the surface layer and the inner layer can be gradually strengthened without destroying the macroscopic structure of the cylinder, thereby realizing directional control of the gradient organization.

[0006] Different from traditional surface deformation strengthening, gradient strengthening requires a deeper feed rate. In order to avoid secondary processing defects and improve the toughening effect at the same time, the present invention also proposes a tooth-shaped roller toughening process combined with two-dimensional ultrasonic vibration. The two-dimensional ultrasonic vibration is set to the meshing direction and the vertical meshing direction of the helical roller respectively. The two-dimensional vibration trajectory is an elliptical plane, whose major axis is consistent with the meshing direction, and the vibration plane is tangent to the helical roller. By controlling the amplitude and phase in the two excitation directions and realizing the combination of the two directions, the shear angle can be increased, which can more effectively help optimize the deformation in the helical tooth embossing direction. The roller flat wheel adopts a simple radial plus tangential two-dimensional vibration, which helps to promote stress transfer, alleviate excessive elongation and instability of the cylinder wall, and ensure dimensional stability after strengthening.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is: An additive manufacturing cylindrical part surface toothed roller toughening equipment comprises a lower die seat, an upper die seat located above the lower die seat, and a plurality of guide columns fixedly arranged between the lower die seat and the upper die seat, a rotating base is arranged in the lower die seat, a positioning assembly is arranged on the rotating base, a first vertical positioning mechanism is arranged on the bottom surface of the upper die seat, an inner wall ultrasonic roller device is fixedly connected to the bottom positioning end of the first vertical positioning mechanism, and the inner wall ultrasonic roller device comprises an inner wall radial groove seat, an inner wall roller seat symmetrically slidably arranged at both ends of the inner wall radial groove seat, and an inner wall roller rotatably arranged at the outer end of the inner wall roller seat and arranged vertically with its axis; Two groups of outer wall ultrasonic roller devices are symmetrically arranged at both ends of the inner wall ultrasonic roller device, and each group of outer wall ultrasonic roller devices includes an outer wall radial groove seat, an outer wall roller seat slidably arranged in the outer wall radial groove seat, and an outer wall roller rotatably arranged at the end of the outer wall roller seat and arranged to be assembled with the inner wall roller. The outer wall ultrasonic roller device is connected to the guide column on the corresponding side through a second vertical positioning mechanism. Both the inner wall roller and the outer wall roller are helical cylindrical gears with opposite spiral directions or are cylindrical roller bodies. Ultrasonic vibration devices are also respectively arranged on the inner wall radial groove seat and the outer wall radial groove seat.

[0008] Furthermore, the inner wall ultrasonic roller device also includes a horizontal bidirectional positioning mechanism fixedly arranged on the outer wall of the inner wall radial groove seat, and the two inner wall roller seats are respectively fixedly connected to the two side positioning output ends of the horizontal bidirectional positioning mechanism, and the two inner wall roller seats move toward or away from each other synchronously.

[0009] Furthermore, the horizontal bidirectional positioning mechanism includes a first fixed driving motor, a horizontally rotatable bidirectional screw, and a first nut block respectively threadedly connected to the two ends of the bidirectional screw, one end of the first nut block passes through the inner wall radial groove seat and is fixedly connected to the inner wall roller seat, and the output shaft end of the first driving motor is connected to the middle part of the bidirectional screw through a gear pair.

[0010] Furthermore, first radial guide grooves are respectively provided on the inner surfaces of the upper and lower walls of the inner wall radial groove seat, and the upper and lower ends of the inner wall roller seat are respectively slidably embedded in the first radial guide grooves.

[0011] Furthermore, the outer wall ultrasonic roller device also includes a horizontal positioning mechanism fixedly arranged on the outer wall of the outer wall radial groove seat, the horizontal positioning mechanism includes a fixedly arranged second drive motor, a rotatably arranged screw rod, and a second nut block threadedly connected to the screw rod, one end of the second nut block passes through the outer wall radial groove seat and is fixedly connected to the outer wall roller seat, and the output shaft end of the second drive motor is transmission-connected to one end of the screw rod.

[0012] Furthermore, second radial guide grooves are respectively provided on the inner surfaces of the upper and lower walls of the outer wall radial groove seat, and the upper and lower ends of the outer wall roller seat are respectively slidably embedded in the second radial guide grooves.

[0013] Furthermore, the ultrasonic vibration device includes two groups of ultrasonic vibrators, which are respectively arranged on the vertical side surface of the inner wall roller seat away from the inner wall roller / the outer wall roller seat away from the outer wall roller and on the vertical side surface adjacent thereto.

[0014] Furthermore, the axes of the inner wall roller and the outer wall roller are located in the same vertical plane, and the rotating shaft of the rotating base is located in the vertical plane.

[0015] A process for toughening the surface of a cylindrical part by toothed rolling is also provided, comprising the following steps: S1. Fix the cylindrical part on the rotating base through the positioning assembly; S2, the inner wall roller and the outer wall roller adopt helical cylindrical gears, the inner wall roller and the outer wall roller are initially positioned to the lowest position, and the initial position of the inner wall roller and the outer wall roller is adjusted to make the radial distance between each roller and the cylinder wall the same; S3, setting the workpiece rotation speed, roller radial feed and axial feed parameters and ultrasonic vibration parameters; S4, start the ultrasonic vibration device, and the two sets of inner wall rollers and outer wall rollers are synchronously fed radially toward the cylinder wall to a preset distance at a preset feeding speed, so that the inner wall rollers bite into the inner cylinder wall and the outer wall rollers bite into the outer cylinder wall; S5, the rotating base drives the cylindrical member to rotate at a preset uniform speed. After a preset time, the cylindrical member rotates one circle, and each roller is synchronously fed axially upward at a preset single roller axial width, until the top of each roller exceeds the uppermost end of the cylindrical member, the last rolling is completed and the radial reset is completed, and the equipment is paused; S6, each roller is replaced with a cylindrical roller of the same diameter and positioned to the lowest position, and steps S4 to S5 are repeated to complete the rolling of the cylindrical wall of the cylindrical part; S7, gradually reducing the radial feed distance of each roller biting into the wall thickness by a preset reduction amount, repeating steps S3 to step 6 for a preset number of times, and completing the gradient structure toughening of the barrel wall; S8. Remove the cylindrical part and perform heat treatment optimization and surface repair.

[0016] Furthermore, the radial feed distance of the cylindrical roller body is smaller than the radial feed distance of the helical cylindrical gear in the same pass.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention realizes gradient tissue toughening for one-time additively manufactured cylindrical parts, proposes a process for gradient tissue toughening of additively manufactured cylindrical parts using toothed rolling and rolling flatness, and an overall process equipment designed according to the one-piece molding process characteristics of additively manufactured cylindrical parts. Without changing the workpiece structure, the gradient toughening of the entire inner and outer wall tissue and performance can be achieved with high efficiency, high quality and high degree of freedom, solving the problem that it is difficult to achieve deep tissue modification of already formed cylindrical parts without changing their structure, and the overall structure of the equipment is innovative.

[0018] 2. The roller device of the present invention adopts two-dimensional ultrasonic vibration to assist, which reduces processing force, improves surface quality, enhances material deformation ability, reduces residual stress, and improves processing efficiency through ultrasonic vibration. It solves a series of problems such as surface defects caused by deep tissue modification at large feed rates, insufficient material fluidity, easy wear of rollers, and low efficiency. It effectively achieves the effects of reducing the yield strength of the material, reducing flow stress, alleviating local stress concentration, optimizing the microstructure of the surface and near-surface layers, and promoting more uniform plastic deformation of the surface, forming a more uniform and refined grain structure, improving surface strength and fatigue resistance, and reducing the risk of defects such as cracks. 3. The present invention adopts a helical tooth roller for rolling reinforcement. When the spiral line is fed, it can locally and gradually bite into it, so that the bite is more complete and the roller rotation is more stable. And for the helical tooth structure, when the bite of the previous tooth has not yet ended, the next tooth has already started to bite into it, so that the bite is more complete, continuous and gradual. Compared with the traditional tooth rolling, it realizes smoother roller feeding and rotation and more stable roller pressure, making the roller pressure more uniform and the rolling process more stable.

[0019] 4. The present invention adopts a symmetrical double-helical tooth roller, which can realize two tooth pressing in one pass. Its double spiral cross track and mutually perpendicular cross tooth marks make the roller tooth more efficient, can more effectively accumulate plastic strain while reducing the tooth mark depth, thereby alleviating excessive thinning and elongation of the cylinder wall during roller flattening.

[0020] 5. The present invention adopts a multi-pass roller tooth and roller flattening process, and the feed amount of the roller to the cylinder wall in each pass is gradually reduced, which can alleviate surface defect problems such as crack initiation and stress concentration caused by large feed amount, and at the same time make the gradient change of the organization more significant. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the roller toughening equipment of the present invention; Figure 2 It is a three-dimensional structural schematic diagram of the cylindrical parts assembled on the roller toughening equipment; Figure 3 is a schematic diagram of the three-dimensional structure of the inner wall ultrasonic roller device; Figure 4 It is a structural schematic diagram of the ultrasonic vibration device being assembled on the inner wall roller seat; Figure 5 is a schematic diagram of the three-dimensional structure of the outer wall ultrasonic roller device; Figure 6 for Figure 1 The enlarged structural diagram of the middle A part; Figure 7 This is the equivalent plastic strain diagram of the cylindrical part behind the bottommost ring of roller teeth obtained by simulation; Figure 8 This is the equivalent plastic strain diagram of the cylindrical part after a layer of multi-layer spiral roller teeth obtained by simulation; Fig. 9 The radial distribution and curve of the plastic strain of the cylinder wall in the first roll tooth stage obtained by simulation; Fig.10 The radial distribution and curve of the accumulated plastic strain of the drum wall during the one-pass rolling flat stage obtained by simulation; Fig.11 Schematic diagram of the change in wall thickness and height of the cylinder during a single rolling stage obtained through simulation.

[0022] In the figure: 1, lower die seat; 2, upper die seat; 3, guide column; 4, rotating base; 5, positioning assembly; 501, positioning inner core; 502, positioning pressure ring; 503, positioning wedge; 6, first vertical positioning mechanism; 7, inner wall ultrasonic roller device; 701, inner wall radial groove seat; 702, inner wall roller seat; 703, inner wall roller; 704, horizontal bidirectional positioning mechanism; 7041, first driving motor; 7042, bidirectional screw; 7043 , first nut block; 7044, gear pair; 8, outer wall ultrasonic roller device; 801, outer wall radial groove seat; 802, outer wall roller seat; 803, outer wall roller; 804, horizontal positioning mechanism; 8041, second drive motor; 8042, screw; 8043, second nut block; 9, second vertical positioning mechanism; 901, third drive motor; 902, lifting gear; 903, rack; 10, ultrasonic vibration device; 100, cylindrical part. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0024] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is considered to be "fixed to" another component, it may be directly fixed on the other component or there may be a central component at the same time.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0026] See attached Figures 1 to 6 , an additive manufacturing cylindrical part surface toothed roller toughening equipment, comprising a lower die base 1, an upper die base 2 located above the lower die base 1, and four guide columns 3 fixedly arranged between the lower die base 1 and the upper die base 2, the lower die base 1 is a hollow disc, the upper die base 2 is a solid disc with the same diameter, the guide columns 3 are cylinders, and are evenly arranged in four directions on the top surface of the lower die base 1, forming a stable support frame. Obviously, a gantry arch frame can also be used instead.

[0027] A rotating base 4 is arranged in the lower die base 1. The rotating base 4 is used to place the cylindrical member 100 to be strengthened and provide power for the cylindrical member 100 to rotate. The bottom of the rotating base 4 is driven by a rotating power output device (such as a motor drive mechanism). In this embodiment, the rotating base 4 adopts the torsion platform of the existing torsion forming equipment. The control system of the torsion forming equipment can be directly used to set the rotation process parameters of the rotating base 4. At the same time, the control logic program of other working components is added to the control system, so that the motion logic control of each functional component of the device can be realized.

[0028] The positioning assembly 5 is arranged on the rotating base 4. The positioning assembly 5 comprises a positioning inner core 501 respectively fixedly arranged at the center of the top surface of the rotating base 5 and a positioning pressure ring 502 located outside the positioning inner core 501. The positioning inner core 501 is a disc structure, which is coaxially arranged with the rotating base 5, and its outer diameter matches the inner wall diameter of the bottom end of the cylindrical member 100. After the cylindrical member 100 is placed on the rotating base 4, its bottom end is sleeved on the outside of the positioning inner core 501, and the inner wall of the cylindrical member 100 cooperates with the outer cylindrical side of the positioning inner core 501 to ensure that its axis position and axial verticality (based on the rotation axis of the rotating base 4) are within the preset error range, thereby avoiding problems such as uneven stress distribution and instability over a large area caused by the tilt of the workpiece. The positioning pressure ring 502 is an annular plate, which is coaxially arranged with the positioning inner core 501 and is fastened to the top surface of the rotating base 4 by bolts. A number of (4 in this embodiment) clamping wedges 503 are evenly distributed on the top surface around its central axis. The bottom end of the clamping wedge 503 and the top end of the positioning pressure ring 502 are slidably matched through a dovetail groove structure arranged along the radial direction of the positioning pressure ring 502. An adjusting screw (not shown in the figure) is threadedly connected to the outer side surface of the clamping wedge 503, and the adjusting screw is rotatably arranged on the outer wall of the positioning pressure ring 502. By turning the adjusting screw, the radial position of the clamping wedge 503 on the positioning pressure ring 502 can be adjusted. After the cylindrical component 100 and the positioning inner core 501 are positioned and matched, by adjusting the radial position of each positioning wedge 503, the cylindrical component 100 can be clamped and fixed in coordination with the positioning inner core 501, and the pressure of each clamping wedge 503 can be kept consistent (the surface deformation after clamping should be within 2 to 4 mm), so as to prevent the cylindrical component 100 from sliding due to uneven friction during the rotation process, thereby affecting the subsequent roller strengthening process.

[0029] The bottom surface of the upper die seat 2 is provided with a first vertical positioning mechanism 6, and the bottom positioning end of the first vertical positioning mechanism is fixedly connected with an inner wall ultrasonic roller device 7. The inner wall ultrasonic roller device 7 is used for roller-pressing strengthening of the inner wall surface of the cylindrical member 100, and the first vertical positioning mechanism 6 is used for uniform feeding of the inner wall ultrasonic roller device 7 in the axial direction of the cylindrical member 100, so that the inner wall ultrasonic roller device 7 can achieve full coverage of the inner wall in the axial direction by axially spirally stacking layer by layer. To this end, the first vertical positioning mechanism 6 adopts a power mechanism that can feed and position in sections. In this embodiment, an electric cylinder is preferably used, which can not only meet the needs of uniform linear feeding in the linear direction, but also realize precise positioning. At the same time, the setting and adjustment of the feeding distance and speed can be easily realized by adjusting the control parameters. It is flexible and convenient to use, and the electric cylinder is a commercially available product, which can simplify the structural design of the equipment and reduce the production cost of the equipment.

[0030] like Figure 3As shown, the inner wall ultrasonic roller device 7 comprises an inner wall radial groove seat 701, an inner wall roller seat 702 symmetrically slidably arranged at both ends of the inner wall radial groove seat 701, an inner wall roller 703 rotatably arranged at the outer end of the inner wall roller seat 702 and arranged with its axis vertically, and also comprises a horizontal two-way positioning mechanism 704 fixedly arranged on the outer wall of the inner wall radial groove seat 701, and two inner wall roller seats 703 are respectively fixedly connected to the two side positioning output ends of the horizontal two-way positioning mechanism 704. Specifically, the inner surfaces of the upper and lower walls of the inner wall radial groove seat 701 are respectively provided with first radial guide grooves arranged horizontally, and the upper and lower ends of the inner wall roller seat 702 are respectively slidably embedded in the first radial guide grooves, so that the inner wall roller seat 702 can move horizontally in the inner wall radial groove seat 701, and the radial position adjustment of the inner wall roller 703 thereon is realized by telescoping. Since the two inner wall rollers 703 at both ends need to perform the same rolling reinforcement on the two end sides of the inner wall of the cylindrical member 100 at the same time, in this embodiment, the vertical center plane of the inner wall radial groove seat 701 is set to coincide with the axis of the rotating base 4, and the two inner wall roller seats 702 are symmetrically arranged in the inner wall radial groove seat 701, and the two inner wall roller seats 702 are driven by the horizontal bidirectional positioning mechanism 704 to move synchronously toward or away from each other, keeping the axes of the two inner wall rollers 703 symmetrically distributed on both sides of the axis of the rotating base 4.

[0031] In this embodiment, the horizontal bidirectional positioning mechanism 704 includes a first fixed driving motor 7041, a bidirectional screw rod 7042 that is horizontally rotatable, and first nut blocks 7043 that are respectively threadedly connected to the two ends of the bidirectional screw rod 7042. One end of the first nut block 7043 penetrates the inner wall radial groove seat 701 and is fixedly connected to the inner wall roller seat 702. The output shaft end of the first driving motor 7041 is connected to the middle of the bidirectional screw rod 7042 through a gear pair 7044. Specifically, the first driving motor 7041 adopts a servo motor and is fixedly installed on the inner wall radial groove seat 701 through a motor mounting seat, and its output shaft end is fixedly connected to a driving gear; the two end thread segments of the bidirectional screw rod 7042 have opposite spiral directions, and the two end ends are rotatably arranged on the side of the inner wall radial groove seat 701 through a bearing seat, wherein the outer side of the segment is fixedly sleeved with a driven gear, and the driven gear is meshed with the driving gear for transmission. The bidirectional screw 7042 is driven to rotate by the first driving motor 7041, so that the two first nut blocks 7043 and the inner wall roller seat 702 fixedly connected thereto are driven to move synchronously toward or away from each other through the thread transmission of the bidirectional screw 7042 and the first nut block 7043, so as to realize the feeding of the two inner wall rollers 703 in the radial direction of the inner side of the cylindrical member 100. A first waist-shaped hole is provided on the side wall of the inner wall radial groove seat 701, and the first nut block 7043 is located in the first waist-shaped hole. A stroke control switch (not shown in the figure) is also provided on the side of the inner wall radial groove seat 701 and is located on one side of the first waist-shaped hole, which is used for stroke control of the first nut block 7043.

[0032] like Figure 4 As shown, an ultrasonic vibration device 10 is also provided on the inner wall radial groove seat. The ultrasonic vibration device 10 includes two sets of ultrasonic vibrators, which are respectively provided on the vertical side surface of the inner wall roller seat 702 away from the inner wall roller 703 and on the vertical side surface adjacent thereto. In this way, independent ultrasonic vibrators are respectively provided on the inner wall roller seat 702 along the radial direction and tangential direction of the cylindrical member 100 to coordinate and realize the two-dimensional ultrasonic vibration of the required waveform. Under the two-dimensional ultrasonic vibration, it is convenient to complete the radial loading of the roller to bite into the inner wall of the cylindrical member 100 before roller strengthening, and then the cylindrical member 100 rotates at a uniform speed to drive the roller to passively rotate, so as to realize continuous biting and roller strengthening.

[0033] The inner wall ultrasonic roller device 7 highly integrates the functions of roller, ultrasonic vibration device, bidirectional feeding, etc., realizes the overall simplification of the equipment, and has more possibilities for application scope and process design. Especially for additively manufactured cylindrical parts, the gradient toughening of the thick wall overall structure is realized, and the toughening quality and efficiency are greatly improved by means of ultrasonic vibration.

[0034] Two sets of outer wall ultrasonic roller devices 8 are symmetrically arranged at both ends of the inner wall ultrasonic roller device 7. Figure 5 As shown, each set of outer wall ultrasonic roller devices 8 includes an outer wall radial groove seat 801, an outer wall roller seat 802 slidably arranged in the outer wall radial groove seat 801, an outer wall roller 803 rotatably arranged at the end of the outer wall roller seat 802 and arranged in a relative manner to the inner wall roller 703, and also includes a horizontal positioning mechanism 804 fixedly arranged on the outer wall of the outer wall radial groove seat 801. Specifically, similar to the structure in the inner wall ultrasonic roller device 7, second radial guide grooves are respectively opened on the inner surfaces of the upper and lower walls of the outer wall radial groove seat 801, and the upper and lower ends of the outer wall roller seat 802 are respectively slidably embedded in the second radial guide groove, so that the outer wall roller seat 802 can move horizontally in the outer wall radial groove seat 801, and the radial position adjustment of the outer wall roller 803 thereon is achieved by telescoping. In this embodiment, the axes of the inner wall roller 703 and the outer wall roller 803 are located in the same vertical plane, and the rotating shaft of the rotating base 4 is located in the vertical plane. In this way, after the inner wall roller 703 and the outer wall roller 803 on the same side work in pairs, the side wall of the cylindrical member 100 on one side can be clamped and rolled, and the positions of the rollers on both sides are located at the two ends of the diameter of the horizontal cross-section of the cylindrical member 100, so that the positions of the rollers on both sides are symmetrically arranged on both sides of the cylindrical member 100, avoiding the problem of uneven force and deformation of the cylindrical member 100 caused by single-sided rolling.

[0035] like Figure 5As shown, in this embodiment, the horizontal positioning mechanism 804 includes a fixed second drive motor 8041, a rotatable screw rod 8042, and a second nut block 8043 threadedly connected to the screw rod 8042. One end of the second nut block 8043 penetrates the outer wall radial groove seat 801 and is fixedly connected to the outer wall roller seat 802. The output shaft end of the second drive motor 8041 is in transmission connection with one end of the screw rod 8042. Specifically, the second drive motor 8041 also adopts a servo motor and is fixedly installed on the outer wall radial groove seat 801 through a motor mounting seat. The two end portions of the screw rod 8042 are rotatably arranged on the side of the outer wall radial groove seat 801 through a bearing seat. The output shaft end of the second drive motor 8041 is in transmission connection with one end of the screw rod 8042. The screw rod 8042 is driven to rotate by the second driving motor 8041, so that the second nut block 8043 and the outer wall roller seat 802 fixedly connected thereto are driven to move horizontally through the threaded transmission of the screw rod 8042 and the second nut block 8043, so as to realize the feeding of the outer wall roller 803 thereon in the radial direction of the outer side of the cylindrical member 100. A second waist-shaped hole is provided on the side wall of the outer wall radial groove seat 801, and the second nut block 8043 is located in the second waist-shaped hole. A stroke control switch (not shown in the figure) is also provided on the side of the outer wall radial groove seat 801 and is located on one side of the second waist-shaped hole, which is used for stroke control of the second nut block 8043.

[0036] Similar to the inner wall radial groove seat 701, the outer wall radial groove seat 801 is also provided with an ultrasonic vibration device 10. The ultrasonic vibration device 10 also includes two sets of ultrasonic vibrators, which are respectively arranged on the vertical side surface of the outer wall roller seat 802 away from the outer wall roller 803 and on the vertical side surface adjacent thereto. The inner wall roller 703 and the outer wall roller 803 are both helical cylindrical gears with opposite spiral directions or are both cylindrical roller bodies. In this way, when the roller pair adopts symmetrically arranged helical cylindrical gears, after the roller pair clamps the side wall of the cylindrical member 100 and rolls, a cross tooth mark can be formed on the inner and outer surfaces of the side wall of the cylindrical member 100, making the rolling efficiency higher and alleviating the common problems of thinning and lengthening in the rolling process.

[0037] In order to facilitate the manufacture of components and improve the commonality between components, in this embodiment, the inner wall radial groove seat 701 of the inner wall ultrasonic roller device 7 is formed by relatively splicing two outer wall radial groove seats 801, and the inner wall roller seat 702 has the same structure as the outer wall roller seat 802. When the inner wall roller 703 and the outer wall roller 803 are both cylindrical roller bodies, the structures of the two are also the same.

[0038] The outer wall ultrasonic roller device 8 is connected to the guide column 3 on the corresponding side through the second vertical positioning mechanism 9, and the outer wall ultrasonic roller device 8 is fed and positioned in the axial direction of the cylindrical member 100 through the second vertical positioning mechanism 9. Figure 5As shown, the second vertical positioning mechanism 9 includes a rack 903 fixedly arranged vertically on the side wall of the guide column 3 close to the rotating base 4, a third driving motor 901 fixedly installed on the top surface of the outer wall radial groove seat 801 through a motor mounting seat, and a lifting gear 902 fixedly installed on the output shaft end of the third driving motor 901 and meshing with the rack 903 for transmission. Among them, the third driving motor 901 also adopts a servo motor, which drives the lifting gear 902 to rotate, and realizes the overall lifting and positioning of the outer wall ultrasonic roller device 8 through the gear rack transmission. To this end, a through hole matching the outer diameter of the guide column 3 is opened at the tail of the outer wall radial groove seat 801, and the guide column 3 is located in the through hole to realize the vertical guidance of the outer wall ultrasonic roller device 8 on the guide column 3; a chord plane is set on the side wall of the guide column 3 close to the rotating base 4, so that a space is left between it and the inner wall of the through hole, so that the rack 903 is located in the space and does not interfere with the inner wall of the through hole.

[0039] The cylindrical part 100 after additive manufacturing or machining may have large residual stress, and it is necessary to reduce the internal stress through stress relief annealing to improve the stability of the rolling process. At the same time, according to the material properties, solid solution treatment and aging treatment can be implemented to optimize the matrix structure, obtain a uniform and stable performance foundation, and provide ideal conditions for rolling strengthening. Before rolling, the surface of the workpiece needs to be thoroughly cleaned to remove grease, scale and dirt, and ensure that the roller is in full contact with the workpiece surface. This can be done by ultrasonic cleaning, chemical cleaning or sandblasting. At the same time, a protective lubricant or solid lubricating film is applied to the surface of the cylindrical part 100 before rolling to reduce the friction coefficient during rolling, reduce surface damage and improve processing quality.

[0040] The present invention also provides a process for toughening the surface of a cylindrical part by toothed rolling by additive manufacturing, comprising the following steps: S1. Fix the cylindrical member 100 on the rotating base 4 through the positioning assembly 5.

[0041] Before performing this step, it is necessary to ensure that the inner wall ultrasonic roller device 7 and the outer wall ultrasonic roller device 8 are both located at the highest vertical position to facilitate the installation operation of the workpiece; at the same time, the inner wall roller seat 702 is retracted to the innermost end of the inner wall radial groove seat 701, and the outer wall roller seat 802 is retracted to the innermost end of the outer wall radial groove seat 801, so that the radial spacing between the inner wall roller 703 and the outer wall roller 803 on the same side is large enough, so that after the cylindrical member 100 is installed and fixed, the roller pair can smoothly enter the bottom of the side wall of the cylindrical member 100.

[0042] After ensuring that the roller pair is at a safe height, the cylindrical member 100 is installed between the positioning inner core 501 and the positioning pressure ring 502. The good cooperation with the positioning inner core 501 ensures that the cylindrical member 100 is in the exact center of the rotating base 4 and its axial verticality is within the error range, avoiding problems such as uneven stress distribution and instability over a large area caused by the tilt of the workpiece. Then, the positioning wedge 503 cooperates with the positioning inner core 501 to press the side wall of the cylindrical member 100 against each other and keep the clamping pressure at all locations consistent, preventing the workpiece from sliding due to uneven friction during the rotation process.

[0043] S2, the inner wall roller 703 and the outer wall roller 803 use helical cylindrical gears, the inner wall roller 703 and the outer wall roller 803 are initially positioned to the lowest position, and the initial position of the inner wall roller 703 and the outer wall roller 803 is adjusted so that the radial distance between each roller and the cylinder wall is the same.

[0044] Since the additively manufactured cylindrical part 100 inevitably has slight dimensional deviations, the rollers need to be positioned before the roller-pressing strengthening process begins. After each roller is synchronously axially fed to the bottom of the cylindrical part 100, the radial distance between each roller and the inner and outer walls of the cylindrical part 100 is adjusted uniformly and maintained at 15 mm to ensure the same feeding distance to the cylinder wall.

[0045] S3. Set the workpiece rotation speed, roller radial feed and axial feed parameters, and ultrasonic vibration parameters.

[0046] For 2 series aluminum alloy, the vibration frequency of the ultrasonic vibration device 10 is set to 20kHz, the amplitude is 15μm, and the power is set to 1000W. Each ultrasonic vibration device 10 is turned on before the roller feed to achieve two-dimensional vibration. The radial feed speed of the roller is set to 1mm / s, and the workpiece speed is set to 0.628rad / s, that is, the cylindrical part 100 rotates one circle in 10s, and the corresponding rotation angle is 2π. Within the rotation period of the cylindrical part 100 (i.e. 10s), the axial feed distance is equal to or less than the axial thickness of the roller to ensure that the tooth marks of the roller completely cover the cylinder wall.

[0047] S4, start the ultrasonic vibration device 10, and the two groups of inner wall rollers 703 and outer wall rollers 803 are synchronously fed radially toward the cylinder wall to a preset distance at a preset feeding speed, so that the inner wall rollers 703 bite into the inner cylinder wall and the outer wall rollers 803 bite into the outer cylinder wall.

[0048] After the ultrasonic vibration device 10 is started, the horizontal bidirectional positioning mechanism 704 drives the two inner wall rollers 703 to gradually approach the inner walls on both sides of the cylindrical member 100 synchronously, and the horizontal positioning mechanisms 804 on both sides respectively drive the outer wall rollers 803 to gradually approach the outer walls on both sides of the cylindrical member 100, until each roller is radially fed to the cylinder wall to a set distance, and the horizontal bidirectional positioning mechanism 704 and the horizontal positioning mechanism 804 both stop working. For the gradient structure strengthening of the rocket compartment, the outer cylindrical side wall of the helical gear is fed to 15% of the wall thickness.

[0049] S5, the rotating base 4 drives the cylindrical member 100 to rotate at a preset uniform speed. After a preset time, the cylindrical member 100 rotates one circle, and each roller synchronously feeds axially upward at a preset single roller axial width. During the uniform rotation of the cylindrical member 100, the inner wall roller 703 and the outer wall roller 803 on the same side passively rotate, thereby rolling the inner and outer surfaces of the cylindrical member 100 in coordination, achieving continuous biting and rolling strengthening, and the double helix cross tracks on both sides can form cross teeth marks on the inner and outer surfaces of the side wall of the cylindrical member 100, making the rolling efficiency higher, while alleviating the common thinning and elongation problems in the rolling process.

[0050] After the cylindrical member 100 rotates one circle, the bottom of the side wall is completely covered and rolled. At this time, the first vertical positioning mechanism 6 drives the inner wall ultrasonic roller device 7 to start axially rising at a preset speed, and the second vertical positioning mechanism 9 drives the outer wall ultrasonic roller device 8 and the inner wall ultrasonic roller device 7 to rise axially synchronously. For each rotation of the cylindrical member 100, the two roller devices move axially by a preset axial distance to ensure that the tooth marks completely cover the cylinder wall. Under the combined effect of the rotation of the cylindrical member 100 and the axial linear movement of the rollers, the double helix trajectory of the cylinder wall is strengthened. The last rolling is completed until the top of each roller exceeds the uppermost end of the cylindrical member 100. The horizontal bidirectional positioning mechanism 704 drives the two inner wall rollers 703 to gradually move away from the inner walls on both sides of the cylindrical member 100 synchronously. At the same time, the horizontal positioning mechanisms 804 on both sides respectively drive the outer wall rollers 803 to gradually move away from the outer walls on both sides of the cylindrical member 100, completing the radial reset of each roller, and then the equipment is paused.

[0051] S6. Each roller is replaced with a cylindrical roller of the same diameter and positioned to the lowest position, and steps S4 to S5 are repeated to complete the rolling of the cylindrical wall of the cylindrical part. Due to the innovative cross stamping, when rolling, the radial feed distance of the roller toward the wall thickness is changed to 8% of the wall thickness, and the radial feed distance of the cylindrical roller is smaller than the radial feed distance of the helical cylindrical gear in the same pass.

[0052] S7, gradually reducing the radial feed distance of each roller biting into the wall thickness by a preset reduction amount, repeating steps S3 to step 6 to a preset number of times, and completing the gradient structure toughening of the cylinder wall. In this embodiment, the radial feed distance of the next pass is 80% of the radial feed distance of the previous pass, that is, the radial feed distance reduction of each pass is 20%.

[0053] S8. Remove the cylindrical member 100 and perform heat treatment optimization and surface repair.

[0054] Each positioning wedge 503 is moved radially outward to release the clamping of the cylindrical member 100. At this time, each roller wheel that has completed roller pressing and strengthening is at the highest point, and the cylindrical member 100 can be removed from the rotating base 4. Then, the surface is thoroughly cleaned by ultrasonic cleaning, chemical cleaning or high-pressure water washing to ensure the effect of subsequent treatment. After appropriate heat treatment optimization and surface repair, the excess waste of the pressing and positioning part is removed by machining.

[0055] This embodiment uses the process simulation function of Simufact Forming software to simulate the surface toothed roller toughening process of additively manufactured cylindrical parts.

[0056] (1) Roller tooth pre-treatment: The driver of the mold uses a table to drive the motor to control its movement speed and trajectory. The general idea is that the roller feeds radially first, then the blank starts to rotate, and the roller feeds axially. At the same time, the spiral strengthening trajectory and depth are designed through the speed of the lower bottom mold (corresponding to the aforementioned rotating base 4), the speed, direction and time parameters of the roller feed.

[0057] Mainly include: 1. Movement of the lower bottom die and the blank (the motor controls the uniform rotation of the lower bottom die to drive the cylindrical blank to rotate at a speed of 0.628rad / s, that is, one circle in 10 seconds. At the same time, the lower bottom die and the blank adopt viscous contact to ensure that there is no excessive relative sliding between the lower bottom die and the blank (the friction coefficient adopts shear friction with a ratio of 0.4).

[0058] 2. Radial movement of the helical rollers (corresponding to the inner wall rollers 703 and outer wall rollers 803 using helical cylindrical gears): When the two pairs of helical rollers are radially fed in the wall thickness direction, two helical rollers will move synchronously in the X direction, and the other two helical rollers will move synchronously in the -X direction. Therefore, in this simulation, two hydraulic presses with mirror motion parameters are used for the four helical rollers. The model is scaled down to a billet wall thickness of 15 mm, and the helical rollers are fed 2 mm in the billet thickness direction by controlling the X-direction speed and motion time.

[0059] 3. Axial movement of the helical roller: The rotation speed of the blank and the axial movement of the helical roller determine the trajectory of the double helix. Combined with the thickness of the roller itself and the height of the cylinder wall, after many attempts, the axial movement speed of the helical roller was set to 2mm / s. Under this parameter, the double helix trajectory can completely cover the entire cylinder wall surface and avoid the repeated coverage of the next layer of helix on the previous layer, making the overall strengthening effect more uniform.

[0060] 4. Temperature and motion constraint parameters: The molding temperature is room temperature, and the temperature rises naturally during deformation; the roller is set to passive rotation, the rotation axis is fixed, and the rotation direction, friction, motion constraint, torque spring and other parameters are set; the bottom mold is set to active rotation, and it is in bonding contact with the blank to drive the rotation.

[0061] (2) Roller tooth post-processing results: Figure 7 and Figure 8 It can be analyzed that the tooth marks of the cylinder wall are improved, and the strain distribution of each tooth mark and between the tooth marks is uniform. The plastic strain gradient effect of the overall wall thickness is obvious, and there is no obvious deformation instability. After the first pass of roller teeth is completed, its gradient accumulated plastic strain meets the requirements; and there is no obvious thinning and elongation of the cylinder wall as a whole, which is convenient for later machining and improves material utilization. Fig. 9 As shown in the figure, 7 equivalent plastic strain reference points are uniformly taken along the radial direction of the cylinder wall to obtain the radial equivalent plastic strain curve of the entire cylinder wall. From the curve, it can be seen that the strain at both ends of the curve is obvious, and the gradient decreases in the middle stage, which fully demonstrates the effect of gradient strengthening of the process.

[0062] (3) Rolling pre-treatment: The radial feed distance of the wall thickness of the rolling wheel (corresponding to the inner wall roller 703 and the outer wall roller 803 using the cylindrical roller body) is changed to 1 mm, and the other parameters are consistent with the above-mentioned rolling tooth process.

[0063] (4) Rolling post-processing results: Fig.10 The figure shows the radial cumulative plastic strain distribution after rolling. Eight points are selected in the radial direction of the cylinder wall to obtain its cumulative plastic strain curve. It can be clearly seen that the cumulative plastic strain distribution shows a trend of gradually increasing at both ends, which fully demonstrates the gradient organization strengthening effect of the process, and the outer wall part with more stringent service conditions has a better strengthening effect. Fig.11 The figure shows the thickness change of the cylinder wall. It can be seen that under this process, only a very small part of the upper end is over-thinned. When measuring the height of the cylindrical part and the thickness of multiple parts, it is found that except for the top part, the maximum thinning rate in the three scattered parts measured is 0.8%, and the overall height has increased by 1.2%, which is within the reasonable range of machining allowance.

[0064] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An additive manufacturing cylindrical part surface toothed roller toughening equipment, comprising a lower die base, an upper die base and a plurality of guide columns, characterized in that: A rotating base is arranged in the lower die seat, a positioning assembly is arranged on the rotating base, a first vertical positioning mechanism is arranged on the bottom surface of the upper die seat, an inner wall ultrasonic roller device is fixedly connected to the bottom positioning end of the first vertical positioning mechanism, and the inner wall ultrasonic roller device comprises an inner wall radial groove seat, an inner wall roller seat symmetrically slidably arranged at both ends of the inner wall radial groove seat, and an inner wall roller rotatably arranged at the outer end of the inner wall roller seat and arranged vertically with its axis; Two sets of outer wall ultrasonic roller devices are symmetrically arranged at both ends of the inner wall ultrasonic roller device, each set of outer wall ultrasonic roller devices comprises an outer wall radial groove seat, an outer wall roller seat slidably arranged in the outer wall radial groove seat, and an outer wall roller rotatably arranged at the end of the outer wall roller seat and arranged to be assembled with the inner wall roller. The outer wall ultrasonic roller device is transmission-connected to the guide column on the corresponding side through a second vertical positioning mechanism; Ultrasonic vibration devices are also respectively arranged on the inner wall radial groove seat and the outer wall radial groove seat.

2. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 1, characterized in that: The inner wall ultrasonic roller device also includes a horizontal bidirectional positioning mechanism fixedly arranged on the outer wall of the inner wall radial groove seat, and two inner wall roller seats are respectively fixedly connected to the positioning output ends on both sides of the horizontal bidirectional positioning mechanism, and the two inner wall roller seats move synchronously toward or away from each other.

3. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 2, characterized in that: The horizontal bidirectional positioning mechanism includes a first fixed driving motor, a bidirectional screw rod arranged to rotate horizontally, and first nut blocks respectively threadedly connected to the two ends of the bidirectional screw rod, one end of the first nut block passes through the inner wall radial groove seat and is fixedly connected to the inner wall roller seat, and the output shaft end of the first driving motor is connected to the middle part of the bidirectional screw rod through a gear pair.

4. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 3, characterized in that: The inner surfaces of the upper and lower walls of the inner wall radial groove seat are respectively provided with first radial guide grooves, and the upper and lower ends of the inner wall roller seat are respectively slidably embedded in the first radial guide grooves.

5. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 1, characterized in that: The outer wall ultrasonic roller device also includes a horizontal positioning mechanism fixedly arranged on the outer wall of the outer wall radial groove seat, the horizontal positioning mechanism includes a fixedly arranged second drive motor, a rotatably arranged screw rod, and a second nut block threadedly connected to the screw rod, one end of the second nut block passes through the outer wall radial groove seat and is fixedly connected to the outer wall roller seat, and the output shaft end of the second drive motor is transmission-connected to one end of the screw rod.

6. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to claim 5, characterized in that: Second radial guide grooves are respectively provided on the inner surfaces of the upper and lower walls of the outer wall radial groove seat, and the upper and lower ends of the outer wall roller seat are respectively slidably embedded in the second radial guide grooves.

7. The surface toothed roller toughening equipment for additively manufactured cylindrical parts according to any one of claims 1 to 6, characterized in that: The ultrasonic vibration device comprises two groups of ultrasonic vibrators, which are respectively arranged on a vertical side surface of the inner wall roller seat away from the inner wall roller / the outer wall roller seat away from the outer wall roller and on a vertical side surface adjacent thereto.

8. The toothed roller toughening equipment for the surface of an additively manufactured cylindrical part according to any one of claims 1 to 6, characterized in that: The axes of the inner wall roller and the outer wall roller are located in the same vertical plane, and the rotating shaft of the rotating base is located in the vertical plane.

9. A process for toughening the surface of a cylindrical part by toothed rolling in additive manufacturing, characterized in that: The following steps are involved: S1, the cylindrical part is fixed on the rotating base; S2, the inner wall roller and the outer wall roller are initially positioned to the lowest position using helical cylindrical gears; S3, setting the workpiece rotation speed, roller radial feed and axial feed parameters and ultrasonic vibration parameters; S4, start the ultrasonic vibration device, and the two sets of rollers are synchronously fed radially toward the cylinder wall until the rollers on both sides bite into the cylinder wall; S5. The rotating base drives the cylindrical member to rotate at a preset uniform speed. After the cylindrical member rotates one circle, each roller synchronously feeds upward by the axial width of a single roller until each roller completely rolls the uppermost end of the cylindrical member, and the equipment is paused. S6, each roller is replaced with a cylindrical roller of the same diameter and positioned to the lowest position, and steps S4 to S5 are repeated to complete the rolling of the cylindrical wall of the cylindrical part; S7, gradually reducing the radial feed distance of each roller biting into the wall thickness by a preset reduction amount, repeating steps S3 to step 6 for a preset number of times, and completing the gradient structure toughening of the barrel wall; S8. Remove the cylindrical part and perform heat treatment optimization and surface repair.

10. The process for toughening the surface of a cylindrical part by toothed rolling in additive manufacturing according to claim 9, characterized in that: The radial feed distance of the cylindrical roller body is smaller than the radial feed distance of the helical cylindrical gear in the same pass.

Images