A laser low stress welding tool and method for thin-walled stainless steel parts

Abstract

The present application belongs to the technical field of laser welding, and particularly discloses a kind of stainless steel thin-walled piece laser low stress welding tool and method. Including: inner support tool, for realizing to cylinder positioning, check and clamping;Inner support tool fixing module, the inner support tool fixing module includes main drive positioner and the driven end rotary support corresponding with the main drive positioner, the main drive positioner and driven end rotary support are all equipped with the three-jaw chuck of clamping the inner support tool;Corrugated plate assembly, for after constraint fixing to corrugated plate, with inner support tool fixed connection;Path planning module, for according to laser welding process parameter planning welding path;Laser welding module, for according to laser welding process parameter and welding path, using quasi-continuous laser to stainless steel thin-walled piece is welded.The present application forms effective positioning clamping to welding workpiece, simultaneously optimizes welding path, reduces welding thermal deformation, and welding quality is good.

Description

Technical Field

[0001] This invention belongs to the field of laser welding technology, and more specifically, relates to a laser low-stress welding fixture and method for thin-walled stainless steel parts. Background Technology

[0002] Cylindrical components made by rolling and welding thin stainless steel sheets have large tolerances in circumferential diameter and poor roundness. Corrugated arc-shaped hangers made by stamping thin stainless steel sheets are difficult to maintain in their ideal shape due to the high elasticity of stainless steel. Therefore, the welding of assemblies composed of cylindrical bodies and corrugated plate hangers is challenging. Figure 1 As shown. The welded assembly is as follows. Figure 2 As shown, the actual corrugated plate is welded onto the cylinder. One of the difficulties lies in the assembly of the corrugated arc-shaped hanger and the cylinder. The corrugated arc-shaped hanger and the cylinder must first be shaped to maintain an ideal or near-ideal shape. This is achieved using a contouring fixture for the corrugated arc-shaped hanger to constrain and shape it, such as... Figure 3 As shown, the roundness of the cylinder is shaped using an internal support fixture. The second challenge lies in the location of the weld bead: overlapping welding is performed at the contact points between each corrugated arc-shaped hanger and the cylinder, such as... Figure 4 As shown, the distance between troughs (channels) is small, resulting in a high weld density. This can lead to a large local heat input, causing uneven heating and cooling inside thin-walled stainless steel materials, which generates residual welding stress. In areas with high temperatures, the weld expansion is large and the stress is increased, while in areas with low temperatures, the weld expansion is small and the stress is small. This leads to a decrease in weld quality, significant weld deformation, a large amount of subsequent correction work, and in severe cases, affects its performance.

[0003] Compared to traditional welding, pulsed laser welding can achieve high power density with a relatively low average output power per pulse, offering more flexible control over heat input. It boasts advantages such as concentrated energy, low heat input, narrow weld seams, and minimal deformation. Furthermore, the focused laser beam produces a very small spot size for precise positioning, and there is no mechanical force interaction between the laser beam and the workpiece during welding. These characteristics make laser welding more suitable for welding ultra-thin-walled workpieces than other methods. Under pulsed laser welding conditions, combined with flexible welding fixtures, thin-walled stainless steel parts can be shaped, positioned, and clamped to ensure high-quality, high-efficiency welding. Based on this, numerical simulation and experimental methods are used to determine the optimal welding path and process parameters. This combined approach enables laser welding of thin-walled, low-stress stainless steel components. Summary of the Invention

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a kind of stainless steel thin-walled piece laser low stress welding tool and method, it is under the condition of pulse laser welding, cooperate flexible welding tool, shaping, positioning, clamping to thin-walled stainless steel parts, ensure that the working condition of welding can meet the conditions of high quality, high efficiency welding, on this basis cooperate numerical simulation and simulation technology and test mode to determine the optimal welding implementation path and welding process parameters, by this combined method realizes the laser welding of stainless steel thin-walled low stress piece, on the one hand, it can guarantee the quality of welded seam, on the other hand, it can use automatic processing means to improve production efficiency.In addition, by using high-quality welding heat source, the heat input during welding of the workpiece can be reduced, the welding thermal deformation can be reduced, and the purpose of green energy saving can be achieved;By combining numerical simulation and test, the welding quality of the whole workpiece is effectively improved.

[0005] To achieve the above object, according to one aspect of the present application, a kind of stainless steel thin-walled piece laser low stress welding tool is provided, comprising:

[0006] The inner support tool is used to position, check and clamp the cylinder;

[0007] The inner support tool fixing module comprises a main drive positioner and a driven end rotary support corresponding to the main drive positioner, and a three-jaw chuck for clamping the inner support tool is arranged on the main drive positioner and the driven end rotary support;

[0008] The corrugated plate assembly is used to constrain and fix the corrugated plate and is fixedly connected with the inner support tool;

[0009] The path planning module is used to plan the welding path according to the laser welding process parameters;

[0010] The laser welding module is used to weld the stainless steel thin-walled piece with quasi-continuous laser according to the laser welding process parameters and the welding path.

[0011] As a further preferred, the inner support tool comprises an inner support spindle, an inner support support, a plurality of radius adjustable supports movably connected with the inner support support arranged along the circumference of the cross section of the inner support spindle, and an inner support drive for driving the radius adjustable supports to move radially along the inner support spindle, in this way, the circular cross section formed by the plurality of radius adjustable supports is adjusted according to the radius design requirements of the cylinder;

[0012] The inner support tool further comprises an outer pressure support ring arranged at both ends of the inner support spindle in the axial direction, wherein the outer pressure support ring is fixedly connected with the inner support spindle.

[0013] As a further preferred, the inner support tooling fixing module comprises a workbench, and a sliding rail is arranged on the workbench for supporting movement of the driven end rotary support, and the sliding rail is arranged along the axis of the inner support main shaft.

[0014] As a further preferred, the corrugated plate assembly includes an assembly body and a plurality of constraint members fixed on the assembly body, the constraint members are used to constrain one wave crest of the corrugated plate, so that the shape of the wave crest meets the design requirements, and the adjacent constraint members are arranged at intervals to reserve a weld seam for welding of the corrugated plate.

[0015] As a further preferred, the corrugated plate assembly further includes a plurality of outer clamping tools for fixedly mounting the assembly body on the inner support tooling, and the outer clamping tool includes a mounting surface fixing member arranged on the circumferential outer wall of the inner support tooling and an outer clamping mounting member correspondingly arranged on the mounting surface fixing member for fixing the assembly body on the mounting surface fixing member.

[0016] As a further preferred, the path planning module includes: according to the laser welding process parameters, multi-physical field coupling simulation is performed on the welding process to predict the dynamic behavior of the molten pool and the mechanical properties of the welded joint in the welding process; a weld spacing optimization model is constructed by comprehensively considering the dynamic behavior of the molten pool and the mechanical properties of the welded joint, so as to obtain the optimal weld spacing of the adjacent two welding processes on the same corrugated plate, and according to the same, the welding paths of a plurality of linear welds arranged at intervals on a plurality of corrugated plates are planned.

[0017] As a further preferred, the laser welding module includes a quasi-continuous laser for welding.

[0018] According to another aspect of the present application, a laser low-stress welding method for a stainless steel thin-walled part is also provided, which includes the following steps:

[0019] Step one, the inner support tooling is used to position, inspect and clamp the cylinder, and then the main drive displacement machine and the driven end rotary support are driven to act to clamp the inner support tooling;

[0020] Step two, after the corrugated plate assembly is used to constrain and fix the corrugated plate, the positional relationship of the corrugated plate relative to the cylinder is converted into the positional relationship of the corrugated plate assembly relative to the cylinder, so as to position the corrugated plate, and the rotational angle of the inner support tooling is adjusted according to the positioning, and the corrugated plate assembly is fixedly connected with the inner support tooling, so as to sequentially complete the positioning and fixing of the corrugated plate.

[0021] Step three, according to the laser welding process parameters and the welding path, a quasi-continuous laser is used to weld the stainless steel thin-walled part.

[0022] As a further preferred, the step two includes the following steps:

[0023] (201)According to the shape design of the corrugated plate, the shape of the constraint part and the spacing distance between adjacent constraint parts are designed, so that under the constraint action of the constraint part, the wave crest shape of the corrugated plate meets the design requirements, and the spacing distance between adjacent constraint parts covers at least the weld to be processed;

[0024] (202)The position relationship of the corrugated plate relative to the cylinder is converted into the position relationship of the corrugated plate assembly relative to the cylinder, and according to the position relationship, the first corrugated plate assembly with corrugated plate is installed on the inner support tool, then the inner support tool is rotated to a specified angle, and the installation of the next corrugated plate assembly with corrugated plate is carried out, until all the corrugated plate assemblies with corrugated plate are installed.

[0025] As a further preferred, the step three includes the following steps:

[0026] (301)According to the laser welding process parameters, multi-physical field coupling simulation is carried out on the welding process to predict the dynamic behavior of the molten pool and the mechanical properties of the welded joint in the welding process;

[0027] (302)A weld spacing optimization model considering the dynamic behavior of the molten pool and the mechanical properties of the welded joint is constructed to obtain the optimal weld spacing between two adjacent welding processes on the same corrugated plate, and the welding path of multiple linear welds arranged at intervals on multiple corrugated plates is planned;

[0028] (303)The first weld of each corrugated plate is processed in turn until the first weld of all corrugated plates is processed;

[0029] (304)According to the optimal weld spacing between two adjacent welding processes of each corrugated plate, the second weld of each corrugated plate is processed in turn until the second weld of all corrugated plates is processed;

[0030] (305)Repeat step (304) until all the welds on all the corrugated plates are processed.

[0031] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0032] 1. The present application adopts a flexible welding tool to clamp the workpiece. The main body of the flexible tool can effectively position and clamp the workpiece. The tool can act as a mold, a gauge, and a clamp, and can also accommodate workpieces of different sizes, with flexible multi-function and multi-dimension. This tool can ensure that the incoming quality of the thin-walled corrugated plate and the thin-walled cylinder, the assembly quality, and the gap between the to-be-welded assembly meet the welding requirements, thereby laying a foundation for ensuring the final welding quality.

[0033] 2. The present application adopts a laser welding heat source with low heat input and low heat affected zone, and the laser light source has controllable and adjustable parameters such as laser power, pulse frequency, pulse width, duty cycle, waveform control, etc., which can reduce the heat input of the welding heat source under the premise of ensuring the quality of the welding seam.

[0034] 3. The present application adopts numerical simulation and simulation technology to reasonably plan the welding path and avoid local concentration of welding heat, which leads to local thermal deformation and affects the accuracy of the entire workpiece.

[0035] 4. The present application adopts orthogonal test method to determine the optimal welding process parameters, and the quality of laser welding is the result of the joint action of multiple factors. The optimal process parameters are obtained through scientific test, so as to realize laser low stress welding of stainless steel thin-walled parts. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 (a) in the figure is the theoretical corrugated plate shape, Figure 1 (b) in the figure is the actual corrugated plate shape, Figure 1 (c) in the figure is the theoretical cylindrical shape, Figure 1 (d) in the figure is the actual cylindrical shape;

[0037] Figure 2 is a schematic diagram of the present application related to the assembly welding of stainless steel thin-walled workpieces;

[0038] Figure 3 is a schematic diagram of the present application related to the profiled arc-shaped pendant profile tooling;

[0039] Figure 4 is a schematic diagram of the present application related to the welding seam position;

[0040] Figure 5 is a schematic diagram of the present application related to a kind of stainless steel thin-walled part laser low stress welding tooling structure

[0041] Figure 6 is a schematic diagram of the present application related to the result of the inside support tooling;

[0042] Figure 7 is a schematic diagram of the present application related to the structure of corrugated plate assembly;

[0043] Figure 8 is a schematic diagram of the present application related to the installation and positioning of corrugated plate. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0045] Embodiment 1

[0046] As Figures 1 to 7 shown, the laser low-stress welding tool for stainless steel thin-wall parts provided by the embodiment of the present application comprises: an inner support tool 1 for positioning, checking and clamping the cylinder 4; an inner support tool fixing module 2 comprising a main drive positioner 21 and a driven end rotary support 22 corresponding to the main drive positioner 21, and a three-jaw chuck 23 for clamping the inner support tool 1 is arranged on the main drive positioner 21 and the driven end rotary support 22; a corrugated plate assembly 3 for fixing the corrugated plate 5 and fixedly connected with the inner support tool 1; a path planning module for planning a welding path according to laser welding process parameters; and a laser welding module for welding the stainless steel thin-wall part by using quasi-continuous laser according to the laser welding process parameters and the welding path.

[0047] Optionally, in the embodiment, the inner support tool 1 comprises an inner support spindle 11, an inner support support 12, a plurality of radius-adjustable support members 13 movably connected with the inner support support 12 and arranged in the circumferential direction of the cross section of the inner support spindle 11, and an inner support driving member for driving the radius-adjustable support members 13 to move radially along the inner support spindle 11. In this way, the circular cross section formed by the plurality of radius-adjustable support members 13 is adjusted according to the radius design requirements of the cylinder 4. The inner support tool 1 further comprises an outer pressure support ring 14 arranged at both axial ends of the inner support spindle 11, wherein the outer pressure support ring 14 is fixedly connected with the inner support spindle 11. Optionally, the inner support driving member can be a conventional motor drive or a driving mechanism capable of driving the radius-adjustable support members 13 to move radially along the inner support spindle 11, which are both applicable to the present application.

[0048] Optionally, in the embodiment, the inner support support 12 is in a circular structure, and a sliding groove for moving the radius-adjustable support members 13 is arranged on the circular structure. Correspondingly, in the preferred embodiment of the present application, the number of radius-adjustable support members 13 corresponds to the number of corrugated plates, and the axial distribution of the radius-adjustable support members 13 along the inner support spindle 11 corresponds to the axial distribution of the corrugated plates along the cylinder. More specifically, in the embodiment, the radius-adjustable support member 13 is in an L-shaped structure, and the area of the plate arranged in the circumferential direction of the inner support spindle 11 covers at least the area of the corrugated plate arranged correspondingly.

[0049] Optionally, in the embodiment, the inner support tooling fixing module 2 comprises a workbench 24, and the workbench 24 is provided with a sliding rail for moving the driven end rotary support 22, and the sliding rail is arranged along the axis of the inner support main shaft 11.

[0050] Optionally, in the embodiment, the corrugated plate assembly 3 comprises an assembly body 31 and a plurality of constraint members 32 fixed on the assembly body 31, and the constraint members 32 are used for constraining a wave crest of the corrugated plate, so that the shape of the wave crest meets the design requirements, and the constraint members 32 are arranged at intervals to reserve a weld seam 6 for welding the corrugated plate 5.

[0051] Optionally, in the embodiment, the constraint member 32 is a V-shaped structure, and the V-shaped structure constrains two side edges of the wave crest, so that the shape of the wave crest meets the design requirements.

[0052] Optionally, in the embodiment, the corrugated plate assembly 3 further comprises a plurality of outer clamping toolings 33 for fixedly mounting the assembly body 31 on the inner support tooling 1, and the outer clamping tooling 33 comprises a mounting surface fixing member arranged on the circumferential outer wall of the inner support tooling 1 and an outer clamping mounting member arranged correspondingly to the mounting surface fixing member and used for fixing the assembly body 31 on the mounting surface fixing member.

[0053] Optionally, in the embodiment, the path planning module comprises: performing multi-physical field coupling simulation on the welding process according to the laser welding process parameters, to predict the dynamic behavior of the molten pool and the mechanical properties of the welded joint in the welding process; constructing a weld seam spacing optimization model considering the dynamic behavior of the molten pool and the mechanical properties of the welded joint, to obtain the optimal weld seam spacing of adjacent two welding processes on the same corrugated plate 5, and to plan the welding path of a plurality of linear weld seams arranged at intervals on a plurality of corrugated plates 5 according to the optimal weld seam spacing.

[0054] Optionally, in the embodiment, the laser welding module comprises a quasi-continuous laser for welding.

[0055] Embodiment 2

[0056] The embodiment provides a laser low-stress welding method for a stainless steel thin-walled part, comprising the following steps:

[0057] Step one, the inner support tooling 1 is used to position, inspect and clamp the cylinder 4, and then the main drive displacement machine 21 and the driven end rotary support 22 are driven to act, so as to clamp the inner support tooling 1.

[0058] Specifically, step one comprises the following steps:

[0059] The cylinder and the corrugated plate are inspected respectively to confirm that the quality meets the requirements;

[0060] The tooling fixture is in place, and the cylinder is sleeved on the inner support tooling (in this embodiment, the inner support tooling is composed of four pieces), and is positioned with one end face as the reference (generally, the end where the main drive displacement machine is located is used as the reference for positioning), and the other end is clamped, and the cylinder center is used as the reference for positioning, and the inner support tooling is clamped, thereby achieving the purpose of positioning and clamping the cylinder. More specifically, as shown in Figure 5 , the left end face of the cylinder is used as the reference for positioning, the cylinder center is used as the reference, and the inner support plate is clamped by the outer support; the right outer pressure support ring clamps the cylinder from the right side.

[0061] Step two, after the corrugated plate is fixed and constrained by the corrugated plate assembly, the positional relationship of the corrugated plate relative to the cylinder is converted into the positional relationship of the corrugated plate assembly relative to the cylinder, thereby positioning the corrugated plate, and adjusting the rotation angle of the inner support tooling according to the positioning, and fixing the corrugated plate assembly and the inner support tooling, so as to sequentially complete the positioning and fixing of the corrugated plate;

[0062] Specifically, this step two includes the following steps:

[0063] (201) The shape of the constraint piece 32 and the spacing distance between adjacent constraint pieces 32 are designed according to the shape of the corrugated plate, so that under the constraint action of the constraint piece 32, the wave crest shape of the corrugated plate meets the design requirements, and at the same time, the spacing distance between adjacent constraint pieces 32 covers at least the weld to be processed;

[0064] (202) As shown in Figure 8 , the positional relationship of the corrugated plate 5 relative to the cylinder 4 is converted into the positional relationship of the corrugated plate assembly 3 relative to the cylinder 4, and according to the positional relationship, the first corrugated plate assembly 3 that constrains the corrugated plate 5 is installed on the inner support tooling 1, and then the inner support tooling 1 is rotated to a specified angle, and the installation of the next corrugated plate assembly 3 that constrains the corrugated plate 5 is performed, until all the corrugated plate assemblies 3 that constrain the corrugated plate 5 are installed. Specifically, in one embodiment, as shown in Figure 8 (a), the installation of the first corrugated plate is performed first, and the cylinder 4 is rotated by ninety degrees, and then the installation of the second corrugated plate is performed, as shown in Figure 8 (b), the cylinder 4 is rotated by ninety degrees, and then the installation of the third corrugated plate is performed, as shown in Figure 8 (c), the cylinder 4 is rotated by ninety degrees, and then the installation of the fourth corrugated plate is performed, as shown in Figure 8 (d).

[0065] Step three, according to the laser welding process parameters and the welding path, quasi-continuous laser is used to weld the stainless steel thin-walled part. Specifically as follows:

[0066] (301) According to the laser welding process parameters, the multi-physical field coupling simulation is performed on the welding process to predict the dynamic behavior of the molten pool and the mechanical properties of the welded joint during the welding process;

[0067] (302) A weld spacing optimization model is constructed by comprehensively considering the dynamic behavior of the molten pool and the mechanical properties of the welded joint, so as to obtain the optimal weld spacing between the adjacent two welding processes on the same corrugated plate, and the welding path of the multiple linear welds arranged at intervals on the multiple corrugated plates is planned;

[0068] (303) The first weld of each corrugated plate is sequentially processed by laser, until the first weld of all corrugated plates (5) is processed;

[0069] (304) According to the optimal weld spacing between the adjacent two welding processes of each corrugated plate, the second weld of each corrugated plate is sequentially processed, until the second weld of all corrugated plates is processed;

[0070] (305) Repeat step (304) until all the welds on all the corrugated plates are processed.

[0071] Optionally, in the above steps, the dynamic behavior of the molten pool is affected by multiple factors such as heat input, welding speed, material properties, etc. The weld spacing S needs to be large enough to avoid the overlap of the heat affected zones of adjacent welds, thereby affecting the stability of the molten pool and the welding quality. According to the above multiple factors, a relationship between the heat affected zone (HAZ) width and the weld spacing is constructed.

[0072] In addition, the mechanical properties of the welded joint are affected by the solidification behavior of the molten pool and the microstructure. The weld spacing S needs to be considered to ensure the uniformity and mechanical properties of the welded joint. In this step, a relationship calculation model of temperature gradient G and solidification rate R can be constructed, and the temperature gradient G and the solidification rate R are key parameters affecting the microstructure of the welded joint, and further affecting the mechanical properties.

[0073] In laser welding, a multi-physical field coupling simulation model can comprehensively consider the effects of multiple physical fields such as heat, force, fluid, etc.

[0074] Therefore, a molten pool heat and mass transport model is constructed:

[0075]

[0076] Where ρ is the density, u is the velocity, h is the specific enthalpy, k is the thermal conductivity, and Sh is the heat source term. This model can describe the energy transfer and mass transport processes in the molten pool.

[0077] According to the relationship between the molten pool dynamic behavior and the weld spacing, the relationship between the mechanical properties of the welded joint and the weld spacing, and the molten pool heat and mass transport model, the weld spacing is optimized. In this process, the weld spacing S can be determined, which not only considers the influence of the molten pool dynamic behavior on the welding quality, but also ensures the mechanical properties of the welded joint, and also considers the influence of the molten pool heat and mass transport on the welding process. Such a weld spacing optimization model helps to realize high-quality laser welding process and reduce the influence of adjacent welds in the welding process.

[0078] Embodiment 3

[0079] The embodiment is to solve the problems of large assembly difficulty of stainless steel thin-walled parts and cylindrical parts before welding, difficult to guarantee the weld quality during welding, and large deformation after welding, and provides a laser low-stress welding method for stainless steel thin-walled parts. It contains the following steps:

[0080] (1) Incoming inspection: check the incoming cylinder and corrugated plate respectively, and confirm that the quality meets the requirements;

[0081] (2) Cylinder assembly: the fixture is in place, the cylinder is sleeved on the inner support fixture (the inner support fixture is composed of four parts), one end surface is positioned as a reference, the other end is clamped, the cylinder center is positioned as a reference, and the inner support fixture is clamped, so as to achieve the purpose of positioning and clamping the cylinder.

[0082] In this step, the left end surface of the cylinder is positioned as a reference; the inner support plate is clamped with the outer support as a reference; the right outer pressure support ring clamps the cylinder from the right side.

[0083] (3) Corrugated plate assembly: the corrugated plate is assembled into the profiling fixture, and the corrugated plate is constrained and fixed.

[0084] (4) Positioning and clamping of the first corrugated plate: the combination of the profiling fixture and the corrugated plate is installed on the surface of the cylinder, and the profiling fixture is locked by screws, so as to position and clamp the first corrugated plate.

[0085] In this step, the position relationship of the corrugated plate relative to the cylinder is transferred to the position relationship of the profiling fixture relative to the cylinder, so as to position the corrugated plate; the corrugated plate is clamped by locking the profiling fixture with screws.

[0086] (5) Positioning and clamping of the second corrugated plate: the positioner is rotated by 90°, the combination of the profiling fixture and the second corrugated plate is installed on the surface of the cylinder, and the profiling fixture is locked by screws, so as to position and clamp the second corrugated plate. The specific steps in this step and step (4) are the same.

[0087] (6) Third corrugated plate positioning and clamping: the positioner is rotated by 90°, the combination of the profiling tool and the third corrugated plate is installed on the surface of the cylinder, the profiling tool is locked by screws, and thus the third corrugated plate is clamped; the specific principle of this step is the same as that in step (4).

[0088] (7) Fourth corrugated plate positioning and clamping: the positioner is rotated by 90°, the combination of the profiling tool and the fourth corrugated plate is installed on the surface of the cylinder, the profiling tool is locked by screws, and thus the fourth corrugated plate is clamped; the specific principle of this step is the same as that in step (4).

[0089] (8) Clamping and supporting of the driven end: the tailstock of the driven end moves to clamp and support the welding tool; the tailstock of the driven end clamps and supports the rotating tool to increase the rigidity of the welding tool.

[0090] (9) First corrugated plate welding: the laser welding process parameters are adjusted, and the welds in the first corrugated plate are welded according to specific welding tracks (to ensure small welding heat affected zone and small deformation).

[0091] (10) Test piece welding and inspection: the position of the laser welding head is adjusted to the test piece welding operation area, the test piece is welded, and after the test piece welding is completed, it is sent for inspection; (the inspection frequency can be set by yourself)

[0092] (11) Inspection of the laser welding head protective lens: after passing the inspection, the laser welding head protective lens is inspected, if the lens is not obviously dirty, subsequent welding operation can be performed, and if the lens is obviously dirty, it is replaced; (the inspection frequency can be set by yourself)

[0093] (12) Second corrugated plate welding: the main drive positioner is rotated by 90°, the laser welding process parameters are adjusted, and the welds in the second corrugated plate are welded according to specific welding tracks (to ensure small welding heat affected zone and small deformation).

[0094] (13) Test piece welding and inspection: the position of the laser welding head is adjusted to the test piece welding operation area, the test piece is welded, and after the test piece welding is completed, it is sent for inspection; (the inspection frequency can be set by yourself)

[0095] (14) Inspection of the laser welding head protective lens: after passing the inspection, the laser welding head protective lens is inspected, if the lens is not obviously dirty, subsequent welding operation can be performed, and if the lens is obviously dirty, it is replaced; (the inspection frequency can be set by yourself)

[0096] (15) Third corrugated plate welding: the main drive positioner is rotated by 90°, the laser welding process parameters are adjusted, and the welds in the third corrugated plate are welded according to specific welding tracks (to ensure small welding heat affected zone and small deformation).

[0097] (16) Test piece welding and inspection: adjust the position of the laser welding head to the test piece welding work area, weld the test piece, and after the test piece welding is completed, send it for inspection; (inspection frequency can be set independently)

[0098] (17) Laser welding head protective lens inspection: after passing the inspection, check the laser welding head protective lens. If the lens is not obviously dirty, subsequent welding operations can be performed. If the lens is obviously dirty, it will be replaced; (inspection frequency can be set independently)

[0099] (18) Fourth corrugated plate welding: rotate the main drive positioner by 90°, adjust the laser welding process parameters, and weld the welds inside the fourth corrugated plate according to the specific welding trajectory (to ensure small welding heat affected zone and deformation);

[0100] (19) Test piece welding and inspection: adjust the position of the laser welding head to the test piece welding work area, weld the test piece, and after the test piece welding is completed, send it for inspection; (inspection frequency can be set independently)

[0101] (20) Laser welding head protective lens inspection: after passing the inspection, check the laser welding head protective lens. If the lens is not obviously dirty, subsequent welding operations can be performed. If the lens is obviously dirty, it will be replaced; (inspection frequency can be set independently)

[0102] (21) End: complete the welding process of the cylinder and the four corrugated plates, and the welded parts enter the next process.

[0103] The flexibility of the flexible welding tool in the method steps is reflected in:

[0104] ① The corrugated plate is an arc-shaped thin-walled part with a thickness of only 0.4mm, and the stainless steel material has high elasticity, making it difficult for the corrugated plate to maintain the ideal shape. The rigid profiling tool fixes the actual shape of the corrugated plate and can detect whether the incoming material is qualified. At this time, the profiling tool plays the role of a mold and a gauge;

[0105] ② The inner support plate of the inner support tool is a standard size, which can be used to inspect the inner diameter of the cylinder and clamp the cylinder from the inside to the outside. At this time, the profiling tool plays the role of a gauge and a clamp;

[0106] ③ The combination of the profiling tool and the corrugated plate is positioned and installed on the outer surface of the cylinder, transferring the position relationship of the corrugated plate relative to the cylinder to the position relationship of the profiling tool relative to the cylinder, thereby positioning the corrugated plate. The profiling tool is clamped by screwing, which plays the role of a gauge and a clamp at this time;

[0107] ④ For different diameter specifications of workpieces, the radius of the profiling plate arc surface can be quickly replaced to adapt to different diameters. The radius size can be controlled by the stroke of the inner support mechanism.

[0108] Example 4

[0109] In this embodiment, a method for welding thin-walled stainless steel parts using a special welding heat source, quasi-continuous wave (QCW) laser, is provided, thereby avoiding the problem of welding defects caused by the difficulty in controlling the heat input of traditional welding heat sources. This heat source has multiple advantages in heat input control, which mainly manifest in the following aspects:

[0110] ① High energy density and penetration ability: QCW lasers have high peak power and high energy density, which means they can achieve greater penetration and stronger penetration on materials.

[0111] ② Stable welding process: The pulsed welding method of QCW lasers can avoid the influence of metal plume on laser absorption rate, making the welding process more stable and reducing the occurrence of defects such as spatter and crater, especially in thin plate welding.

[0112] ③ Stability of molten pool: Due to the short action time of QCW lasers, the molten pool mainly exists uniformly around the keyhole, and the force is uniform, so the occurrence rate of defects such as pores, cracks and spatter is relatively low.

[0113] ④ Small heat-affected zone: QCW lasers intermittently act on materials, giving them time to cool down, so the heat-affected zone and heat input are small, making them suitable for processing thin materials and materials close to heat-sensitive components.

[0114] ⑤ High peak power: Compared with continuous lasers of the same average power, QCW lasers can achieve higher peak power.

[0115] ⑥ Flexibility and compatibility: QCW lasers can be set to pulsed or continuous mode, which makes a single laser capable of handling tasks that previously required two different lasers.

[0116] ⑦ Time-domain pulse shaping: QCW lasers can use time-domain pulse shaping technology to provide gradient-changing pulse energy, which is useful for welding thin-walled materials.

[0117] ⑧ Precision machining capability: The high pulse power characteristics of QCW lasers make them perform well in precision laser welding scenarios, especially in applications that require fine control of energy output.

[0118] Example 5

[0119] In this embodiment, a method for planning a welding path is provided, which is achieved through numerical simulation and simulation technology:

[0120] i. Temperature field and molten pool flow simulation: Through simulation software, the temperature field distribution and molten pool flow during laser welding can be simulated. These simulations help to predict potential problems during the welding process, such as weld defects and the formation of heat-affected zones, thereby optimizing welding parameters and improving welding quality.

[0121] ii. Welding defect prediction and control: Numerical simulation techniques can predict potential defects that may occur during the welding process, such as porosity, cracks, and spatter. Through simulation, researchers can analyze the formation mechanisms of these defects and propose corresponding control strategies to improve welding quality.

[0122] iii. Microstructure evolution and residual stress analysis: The microstructure evolution and residual stress during laser welding have a significant impact on the performance of the weld. Numerical simulation can help understand the evolution process of these phenomena and provide theoretical support for reducing residual stress and optimizing weld microstructure.

[0123] iv. Heat source model development: In laser welding simulation, heat source models are crucial. By using models such as Gaussian surface heat source and double-ellipsoid heat source, more accurate laser welding simulation can be achieved in simulation software such as ABAQUS and MSC.Marc.

[0124] v. Multi-physical field coupling simulation: Laser welding is a complex process involving multiple physical fields such as heat, force, and fluid. Through multi-physical field coupling simulation, a more comprehensive understanding and prediction of various phenomena during the welding process can be achieved, such as the dynamic behavior of the molten pool and the mechanical properties of the welded joint.

[0125] In this embodiment, there are a total of 240 welds, evenly distributed in four areas, with 60 welds in each area. The four areas are labeled as A, B, C, and D in sequence. The welds in area A are labeled as A1-A60, the welds in area B are labeled as B1-B60, the welds in area C are labeled as C1-C60, and the welds in area D are labeled as D1-D60. The welding trajectories obtained through numerical simulation and simulation are arranged as follows:

[0126] S1: Take A30 as the starting point of area A, B30 as the starting point of area B, C31 as the starting point of area C, and D31 as the starting point of area D to implement descending arrangement. At this time, the welding path is:

[0127] [A30→C31→B30→D31]→[A29→C30→B29→D30]→[...]→[A1→C2→B1→D2]

[0128] S2: Take A31 as the starting point of area A, B31 as the starting point of area B, C32 as the starting point of area C, and D32 as the starting point of area D to implement descending arrangement. At this time, the welding path is:

[0129] [A31→C32→B31→D32]→[...]→[A59→C60→B59→D60]→[A60→C1→B60→D1]

[0130] By S1, S2 two rounds of welding, 240 welds are completed.

[0131] The optimization of welding process parameters in this method is obtained by orthogonal test method. By reasonably arranging the test conditions, the influence of multiple factors on the test results is evaluated with fewer test times, and the optimal laser welding process parameter combination is found. The factors affecting the welding quality in the process of pulse laser welding are:

[0132] ① Laser power: This is one of the most basic parameters in the welding process, which needs to be adjusted according to the thickness of the material and the welding requirements. The higher the power, the stronger the penetration ability, but at the same time, it will also increase the heat affected zone.

[0133] ② Pulse frequency: The pulse frequency of QCW laser affects the stability of welding and the formation of weld. Too high frequency may lead to insufficient welding, while too low frequency may affect production efficiency.

[0134] ③ Pulse width: Pulse width determines the time of laser acting on the material, affecting the depth and width of the weld. A wider pulse can provide more heat, but it may also increase the heat affected zone.

[0135] ④ Duty cycle: This is the ratio of pulse width to pulse period, which determines the proportion of time the laser emits in a unit of time, affecting the efficiency and quality of welding.

[0136] ⑤ Peak power: The peak power of QCW laser is usually high, which helps the penetration of materials and the formation of welds, especially when welding high-reflective materials.

[0137] ⑥ Average power: Average power determines the total energy input during welding, which needs to be adjusted according to the welding material and thickness.

[0138] ⑦ Defocusing amount: Defocusing amount refers to the distance between the laser focus and the workpiece surface, which affects the focusing and energy distribution of the laser, and thus affects the welding effect.

[0139] ⑧ Welding speed: Welding speed determines the time of laser on the material, too fast speed may lead to insufficient welding, and too slow speed will increase the heat affected zone.

[0140] ⑨ Waveform control: QCW laser can control the waveform of laser through software to adapt to different welding needs.

[0141] The orthogonal test method is designed as follows:

[0142] Step1: determine the test factors and levels, the main factors affecting the welding quality are A laser power, B duty cycle (pulse width to pulse period ratio), C defocusing amount, D laser waveform, E welding speed five factors, select four levels five factors of standard orthogonal test table L16(4 5 ):

[0143] A: 90W, 120W, 150W, 180W; B: 10, 15, 30, 45; C: -1mm, -0.5mm, 0.5mm, 1mm; D: square wave, triangular wave, trapezoidal wave, exponential curve wave; E: 4m / min, 5m / min, 6m / min, 7m / min.

[0144] Step2: arrange the test scheme:

[0145] L16(4 5 )

[0146]

[0147]

[0148] Step3: test result analysis:

[0149] Through 16 groups of experiments, the weld penetration is controlled in 0.8mm±0.1mm as the best, ensure that the back is not welded through, the welding penetration is guaranteed.

[0150] Step4: determine the local optimal welding process parameter combination:

[0151] Calculate the average index of each factor, determine the optimal level of each factor, determine the main factors and secondary factors

[0152] Step5: determine the global optimal welding process parameter combination by multiple test approximation method.

[0153] Through the combination of the above methods: flexible welding tooling, optimized welding heat source, reasonable welding path planning and optimized welding process parameters, realize the low stress laser welding of stainless steel thin-walled parts.

[0154] Those skilled in the art will readily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A laser low stress welding tooling for thin-walled stainless steel parts, characterized in that, The utility model relates to a kind of laser welding device for thin-walled stainless steel, comprising: Inner support tooling (1) for realizing positioning, checking and clamping to cylinder (4); Inner support tooling fixed module (2) includes main drive positioner (21) and driven end rotary support (22) corresponding with the main drive positioner (21), the main drive positioner (21) and driven end rotary support (22) are all equipped with three-jaw chuck (23) for clamping the inner support tooling (1); Corrugated plate assembly (3) is used for fixing constraint after being fixed to corrugated plate (5), and is fixedly connected with inner support tooling (1); Path planning module is used for planning welding path according to laser welding process parameters; Laser welding module is used for welding stainless steel thin-walled piece by quasi-continuous laser according to laser welding process parameters and welding path; The corrugated plate assembly (3) includes an assembly body (31) and a plurality of constraint members (32) fixedly arranged on the assembly body (31), and the constraint members (32) are used for constraining a wave crest of the corrugated plate (5) so that the shape of the wave crest meets the design requirements, and the adjacent constraint members (32) are arranged at intervals to reserve a weld (6) for welding of the corrugated plate (5); The path planning module includes: according to the laser welding process parameters, multi-physical field coupling simulation is carried out on the welding process to predict the dynamic behavior of the molten pool and the mechanical properties of the welded joint in the welding process; A weld spacing optimization model considering the dynamic behavior of the molten pool and the mechanical properties of the welded joint is constructed to obtain the optimal weld spacing between two adjacent welding processes on the same corrugated plate (5), and the welding paths of a plurality of linear welds arranged at intervals on a plurality of corrugated plates (5) are planned accordingly.

2. The laser low stress welding tooling for thin-walled stainless steel parts according to claim 1, characterized in that, The inner support tooling (1) includes an inner support spindle (11), an inner support support (12), a plurality of radius-adjustable support members (13) arranged circumferentially along a cross section of the inner support spindle (11) and movably connected to the inner support support (12), and an inner support driving member for driving the radius-adjustable support members (13) to move radially along the inner support spindle (11), in this way, the circular cross section formed by the plurality of radius-adjustable support members (13) is adjusted according to the radius design requirements of the cylinder (4); The inner support tooling (1) further includes an outer pressure support ring (14) arranged at both axial ends of the inner support spindle (11), wherein the outer pressure support ring (14) is fixedly connected to the inner support spindle (11).

3. The laser low stress welding tooling for thin-walled stainless steel parts of claim 2, wherein, The inner support tooling fixed module (2) includes a workbench (24), and the workbench (24) is provided with a sliding rail for movement of the driven end rotary support (22), and the sliding rail is arranged along the axis of the inner support spindle (11).

4. The laser low stress welding tooling for thin-walled stainless steel parts of claim 1, wherein, The corrugated plate assembly (3) further includes a plurality of outer clamping toolings (33) for fixedly mounting the assembly body (31) on the inner support tooling (1), and the outer clamping toolings (33) include a mounting surface fixing member fitted to the circumferential outer wall of the inner support tooling (1) and an outer clamping mounting member corresponding to the mounting surface fixing member for fixing the assembly body (31) on the mounting surface fixing member.

5. The laser low stress welding tooling for thin-walled stainless steel parts according to any one of claims 1-4, characterized in that, The laser welding module includes a quasi-continuous laser for welding.

6. A method for laser low stress welding of thin-walled stainless steel parts, characterized in that, It comprises the following steps: Step one, adopt inner support tooling (1) to position, check and clamp the cylinder (4), then drive the main drive displacement machine (21) and the driven end rotary support (22) to act, so as to clamp the inner support tooling (1); Step two, after fixing the corrugated plate by using the corrugated plate assembly (3), the position relationship of the corrugated plate (5) relative to the cylinder (4) is converted into the position relationship of the corrugated plate assembly (3) relative to the cylinder (4), so as to position the corrugated plate (5), and adjust the rotation angle of the inner support tooling (1) according to the positioning, and fix the corrugated plate assembly (3) and the inner support tooling (1) to complete the positioning and fixing of the corrugated plate (5) in turn; The step two comprises the following steps: (201) According to the shape of the corrugated plate (5), the shape of the constraint part (32) and the interval distance between the adjacent constraint parts (32) are designed, so that under the constraint action of the constraint part (32), the wave crest shape of the corrugated plate (5) meets the design requirements, and at the same time, the interval distance between the adjacent constraint parts (32) covers at least the weld to be processed; Step three, according to the laser welding process parameters and the welding path, quasi-continuous laser is used to weld the stainless steel thin-walled part; The step three comprises the following steps: (301) According to the laser welding process parameters, multi-physical field coupling simulation is carried out on the welding process to predict the dynamic behavior of the molten pool and the mechanical properties of the welded joint in the welding process; (302) A weld spacing optimization model considering the dynamic behavior of the molten pool and the mechanical properties of the welded joint is constructed to obtain the optimal weld spacing of the adjacent two welding processes on the same corrugated plate (5), and the welding path of the multiple straight line welds arranged on the multiple corrugated plates (5) is planned.

7. The method according to claim 6, wherein The step two further comprises the following steps: (202) The position relationship of the corrugated plate (5) relative to the cylinder (4) is converted into the position relationship of the corrugated plate assembly (3) relative to the cylinder (4), and according to the position relationship, the first corrugated plate assembly (3) with the corrugated plate (5) is installed on the inner support tooling (1), then the inner support tooling (1) is rotated to a specified angle, and the installation of the next corrugated plate assembly (3) with the corrugated plate (5) is carried out, until all the corrugated plate assemblies (3) with the corrugated plate (5) are installed.

8. The stainless steel thin-walled part laser low stress welding method according to claim 7, characterized in that, (303) The first weld of each corrugated plate (5) is sequentially processed by laser, until the first weld of all corrugated plates (5) is processed; (304) According to the optimal weld spacing of the adjacent two welding processes of each corrugated plate (5), the second weld of each corrugated plate (5) is sequentially processed, until the second weld of all corrugated plates (5) is processed; (305) Repeat step (304) until all the welds on all the corrugated plates (5) are processed.

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