Stirring device for friction stir welding and welding method

Abstract

The invention provides a stirring device for friction stir welding and a welding method. The stirring device comprises a stirring shaft shoulder and a stirring needle, and the stirring needle is arranged at the middle axis position of the stirring shaft shoulder; a plurality of cooling channels are arranged in the stirring shaft shoulder and are arranged in a gradient manner in the radial direction of the stirring shaft shoulder; the depth of the cooling channel extends along the axial direction of the stirring shaft shoulder; the plurality of cooling channels are mutually independent, and a cooling medium can be independently introduced into each cooling channel; the multiple cooling channels cover the shaft shoulder influence area and the stirring needle influence area of the friction stir welding seam. By arranging a plurality of cooling runners, a shaft shoulder influence area and a stirring needle influence area can be controlled respectively, meanwhile, for different areas, different cooling effects and local temperature control can be achieved by controlling whether a cooling medium is introduced or not and controlling the type and the flow speed of the cooling medium, the cooling effect is greatly improved, and the service life of the shaft shoulder influence area and the stirring needle influence area is prolonged. And the cooling control precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of friction welding, and in particular to a stirring device and a welding method for stir friction welding, in particular to a welding method for suppressing peeling of high-strength aluminum alloy stir friction welding, and in particular to a manufacturing method for suppressing peeling of the surface of high-strength aluminum alloy stir friction welding, typically 2195 aluminum alloy, and widening the process parameter window. Background Art

[0002] 2195 aluminum alloy is an advanced high-strength aluminum alloy material commonly used in large spacecraft in the existing launch field. Stir friction welding technology provides great technical support for the manufacture of important components such as 2195 aluminum alloy large tanks. However, during the welding process, it was found that the surface of the friction weld of high-strength aluminum alloys represented by 2195 aluminum alloy has bran phenomenon to varying degrees, which is particularly obvious during the welding of large butt circumferential seams. The peeling is bran-like or flaky, such as Figure 1 As shown in the figure, after grinding, discontinuous pits are left on the weld surface, which affects the quality of the weld and increases the complexity of subsequent processing, especially for the strength of large thin-walled components.

[0003] The macroscopic and microscopic morphology of the peeling was preliminarily analyzed. The thickness of the peeling was about 0.1~0.4mm. It was found that the macroscopic morphology of the front and back of the peeling was different. The front of the peeling was relatively smooth, with clear stirring lines and evenly distributed bright white granular precipitation phases. The back was rough, and there was obvious material bonding. The composition scanning results showed that there was basically no difference in the type and content of elements on the front and back of the peeling. The main elements were Al and Cu elements, and the oxygen content was below 3wt.%, which ruled out the peeling caused by the difference in composition between the surface and the core and the oxidation of the surface.

[0004] In addition, during the development of the tank, it was found that the 2319 aluminum alloy welding wire filled with fusion welding and the 2195 aluminum alloy base material and the 2195 aluminum alloy and 2219 aluminum alloy friction stir welds had obvious fusion interfaces. Figure 2 As shown in the figure, 2319 aluminum alloy welding wire is used to fill the friction weld of 2195 aluminum alloy. After sufficient stirring and friction, the fusion welding filling area and the bonding interface are still clearly visible in the X-ray film. This is related to the sufficient plasticization and material transfer of the material in the area affected by the stirring needle.

[0005] According to literature research and experimental analysis, the surface bran phenomenon is caused by the inconsistency of plasticization between the surface and the core material due to surface overheating during aluminum alloy welding. During stir friction welding, the heat generation in the shoulder affected area is the highest, and there is a large temperature difference with the stirring needle affected area. In addition, Figure 2As shown in the figure, there is a phenomenon of insufficient plasticization in the area affected by the stirring needle during the welding process of high-strength aluminum alloy. Therefore, reducing the thermal influence of the shoulder affected area while not affecting the heat generation in the area affected by the stirring needle is crucial to improving the comprehensive quality of high-strength aluminum alloy stir friction welds.

[0006] In the early stage, the shoulder affected area was cooled by air cooling, surface flowing water cooling or a combination of the two, which had a certain improvement effect on the surface peeling phenomenon, but it was difficult to completely eliminate it. In addition, the heat input to the stirring needle affected area was smaller under the large-scale cooling method, resulting in worse material fusion in the stirring needle affected area. Therefore, it is urgent to develop an immediate and effective local shoulder fast cooling method to improve the surface performance of the shoulder affected area without affecting the heat input to the stirring needle affected area.

[0007] The document with the publication number CN1714983A discloses a plasma arc-friction stir composite welding method, which uses a plasma gun as an auxiliary heating heat source. The heat generated by the plasma arc formed by the plasma gun allows the workpiece to be fully preheated before the stirring head passes through. During welding, the stirring head rotates at high speed under the drive of the motor and presses into the workpiece along the butt surface of the workpiece to be welded. When the shoulder of the stirring head is in close contact with the workpiece to be welded, the stirring head moves forward along the butt surface to achieve welding. The welding area is plasticized under the combined action of the friction heat generated by the stirring head and the auxiliary heat generated by the plasma arc, and a weld is formed at the rear of the stirring head. However, the document still has the defect that the heat generation in the shoulder influence area is the highest, and there is a large temperature difference with the stirring needle influence area. Summary of the invention

[0008] In view of the defects in the prior art, an object of the present invention is to provide a stirring device and a welding method for friction stir welding.

[0009] A stirring device for friction stir welding according to the present invention comprises: a stirring shaft shoulder and a stirring needle, wherein the stirring needle is arranged at the center axis position of the stirring shaft shoulder; A plurality of cooling channels are arranged in the stirring shaft shoulder, and the plurality of cooling channels are arranged in a gradient arrangement along the radial direction of the stirring shaft shoulder; the depth of the cooling channel extends along the axial direction of the stirring shaft shoulder; The plurality of cooling channels are independent of each other, and each cooling channel can be independently fed with a cooling medium; The plurality of cooling channels cover the shaft shoulder influence zone and the stirring needle influence zone of the friction stir weld, and can cool the shaft shoulder influence zone and the stirring needle influence zone.

[0010] Preferably, in the radial direction of the stirring shaft shoulder, the arrangement density of the plurality of cooling channels gradually increases from the inside to the outside.

[0011] Preferably, in the radial direction of the stirring shaft shoulder, the widths of the plurality of cooling channels gradually increase from the inside to the outside.

[0012] Preferably, the cooling channel for cooling the shaft shoulder influence zone and the cooling channel for cooling the stirring needle influence zone use different cooling media.

[0013] Preferably, in the radial direction of the stirring shaft shoulder, the specific heat capacity of the cooling medium in the plurality of cooling channels increases gradually from the inside to the outside.

[0014] Preferably, each of the cooling channels is provided with a channel switch; The channel switch is used to control the opening and closing of the cooling channel and / or the flow rate of the cooling medium in the cooling channel.

[0015] Preferably, each of the cooling channels is connected to a cooling medium delivery pipeline via a channel switch.

[0016] Preferably, the stirring device further comprises a temperature measuring unit, and the temperature measuring unit is capable of monitoring the temperature of the shaft shoulder influence zone and the stirring needle influence zone; The temperature measurement unit is connected to a control unit, the control unit is connected to the channel switch, and the control unit controls the opening and closing of the channel switch according to the received temperature measurement data.

[0017] Preferably, the cooling channel is a circular cooling channel with a notch, and a cooling medium inlet and a medium outlet are formed at the notch position; In the radial direction of the stirring shaft shoulder, the notches of the plurality of cooling channels from the inside to the outside are staggered along the circumferential direction.

[0018] The present invention also provides a welding method for stir friction welding, which uses the above-mentioned stirring device for stir friction welding and specifically includes the following steps: Step S1: installing a stirring device; Step S2: determining welding path and welding parameters; Step S3: According to the welding path and welding parameters, the workpiece is stir-welded by a stirring device. During the stirring welding process, the temperature of each area on the stirring shoulder is measured by a temperature measuring unit. According to the temperature measurement data, the opening and closing of the cooling channel and / or the flow rate of the cooling medium in the corresponding area are controlled by a control unit.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention can achieve separate control of the shaft shoulder influence area and the stirring needle influence area by setting a plurality of cooling channels. At the same time, for different areas, different cooling effects can be achieved by controlling whether to introduce cooling medium and controlling the type and flow rate of cooling medium, thereby achieving local temperature control, greatly improving the cooling effect, and improving the accuracy of cooling control.

[0020] 2. The present invention sets multiple cooling channels, and can open cooling channels at different positions and in different numbers at different stages to achieve local cooling. For example, in the initial stage, the heat generation at the outer edge of the shoulder influence zone is relatively high, and the cooling channel located on the outer circle of the shoulder influence zone can be opened first. As the welding path increases, heat accumulates, and the cooling channels close to the center are gradually opened, thereby achieving stage-by-stage local temperature control.

[0021] 3. The present invention adopts radial gradient arrangement of annular multi-cooling channels to achieve fixed-area cooling of the dynamic shoulder influence area and rapid response and precise temperature control strategy to regulate the temperature field, thereby improving the surface quality of high-strength aluminum alloy stir friction welding.

[0022] 4. The present invention is based on the intrinsic thermophysical properties of welding materials and welding tools. According to the differences in heat generation and weld performance within different shoulder influence radii, combined with the cooling structure of the stirring device and real-time process collaborative control, the temperature gradient distribution in the shoulder influence area can be achieved. The temperature of different areas during friction welding can be finely regulated by the layout of radially closely packed surrounding flow channels, selective opening, and introduction of differential coolants. While achieving gradient cooling in the shoulder influence area, the stirring needle influence area can be independently temperature controlled by adding different coolants, and the temperature of the stirring needle influence area does not decrease, thereby improving the material fusion behavior. The combination of the two can simultaneously enhance the strength of high-strength alloy welds, improve the weld surface state, and broaden the friction welding process parameter window.

[0023] 5. The present invention utilizes the radial gradient arrangement of the shoulder area, the multi-cooling flow channel design with independent control of the partitions, and the precise temperature adjustment process of the partition blocks that respond quickly to the local area to obtain a high-strength aluminum alloy stir friction welding structure with a smooth surface and no bran phenomenon.

[0024] 6. The present invention solves the problem of poor surface quality such as bran to varying degrees caused by overheating in different radii of the shoulder influence zone as heat accumulates during welding during the high-strength aluminum alloy stir friction manufacturing process. On the other hand, it provides a simple and easy way of local rapid response temperature regulation, which can be further promoted and applied to related fields such as stir friction additive manufacturing and stir friction processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 Schematic diagram of different degrees of peeling phenomenon of 2195 aluminum alloy friction stir weld; Figure 2 Schematic diagram of the friction stir welding interface of 2195 aluminum alloy / 2219 aluminum alloy; Figure 3 It is a schematic diagram of the vertical cross-sectional structure of the stirring device for friction stir welding of the present invention; Figure 4 It is a schematic diagram of the horizontal cross-sectional structure of the stirring device for friction stir welding of the present invention; Figure 5 It is a schematic diagram showing that the stirring device of the invention is smooth and flat without peeling after welding.

[0026] The figure shows: DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0028] Embodiment 1: like Figure 3 and Figure 4 As shown, this embodiment provides a stirring device for stir friction welding, including: a stirring shoulder 1 and a stirring needle 2, the stirring needle 2 is arranged at the central axis position of the stirring shoulder 1; a plurality of cooling channels 101 are arranged in the stirring shoulder 1, and the plurality of cooling channels 101 are arranged in a gradient manner along the radial direction of the stirring shoulder 1; the depth of the cooling channel 101 extends axially along the stirring shoulder 1; the plurality of cooling channels 101 are independent of each other, and each cooling channel 101 can be individually introduced with a cooling medium; the plurality of cooling channels 101 cover the shoulder influence zone and the stirring needle influence zone of the stir friction weld, and can cool the shoulder influence zone and the stirring needle influence zone.

[0029] Each cooling channel 101 is provided with a channel switch; the channel switch is used to control the opening and closing of the cooling channel 101 and / or the flow rate of the cooling medium in the cooling channel 101. Each cooling channel 101 is connected to the cooling medium delivery pipe 3 through the channel switch. The stirring device also includes a temperature measuring unit, which can monitor the temperature of the shoulder influence area and the stirring needle influence area; the temperature measuring unit is connected to the control unit, the control unit is connected to the channel switch, and the control unit controls the opening and closing of the channel switch through the received temperature measurement data.

[0030] The temperature measurement unit adopts non-contact temperature measurement equipment such as infrared thermometer, which can realize synchronous temperature measurement of the stirring needle and the shoulder influence area.

[0031] In the radial direction of the stirring shaft shoulder 1, the arrangement density of the plurality of cooling channels 101 gradually increases from the inside to the outside. Figure 4 As shown, the density is greater near the edge and smaller near the center.

[0032] In the radial direction of the stirring shaft shoulder 1, the widths of the multiple cooling channels 101 gradually increase from the inside to the outside. Figure 3 As shown, the width of the flow channel near the edge is larger, and the width of the flow channel near the center is smaller.

[0033] The cooling channel 101 for cooling the shaft shoulder influence area and the cooling channel 101 for cooling the stirring needle influence area use different cooling media. In the radial direction of the stirring shaft shoulder 1, the specific heat capacity of the cooling media in the multiple cooling channels 101 increases gradually from the inside to the outside.

[0034] The cooling channel 101 is a circular cooling channel with a notch 102, and a cooling medium inlet and a cooling medium outlet are formed at the notch 102; in the radial direction of the stirring shaft shoulder 1, the notches 102 of the multiple cooling channels 101 from the inside to the outside are staggered along the circumferential direction. The staggered setting is to achieve a more uniform temperature distribution on the entire surface and avoid the temperature of the point being inconsistent with the entire surface when the input points overlap at one place.

[0035] The cooling medium delivery pipe 3 includes a cooling medium input pipe 301 and a cooling medium output pipe 302. The cooling medium input pipe 301 is connected to the cooling medium inlet, and the cooling medium output pipe 302 is connected to the cooling medium outlet, so as to circulate the cooling medium in the cooling channel.

[0036] This embodiment also provides a welding method for friction stir welding, using the above-mentioned stirring device for friction stir welding, and specifically comprising the following steps: Step S1: installing a stirring device; Step S2: determining welding path and welding parameters; Step S3: stir welding the workpiece by a stirring device according to the welding path and welding parameters. During the stirring welding process, the temperature of each area on the stirring shoulder 1 is measured by a temperature measuring unit. According to the temperature measurement data, the opening and closing of the cooling channel 101 and / or the flow rate of the cooling medium in the corresponding area are controlled by a control unit. The cooling channels 101 in the stirring needle influence zone and the shaft shoulder influence zone are controlled separately; Make sure the temperature of the shoulder affected area does not exceed 450℃; Welding speed 500~900rpm, welding speed 100~400mm / min.

[0037] This embodiment provides a method of using radial gradient arranged annular multiple cooling channels to achieve fixed-area cooling of the dynamic shoulder influence area and rapid response and precise temperature control strategy to regulate the temperature field, thereby improving the surface quality of high-strength aluminum alloy stir friction welding.

[0038] This embodiment is based on the intrinsic thermophysical properties of welding materials and welding tools. According to the differences in heat generation and impact on weld performance within different shoulder influence radii, combined with the design of stirring tools and real-time collaborative control of the process, the temperature gradient distribution in the shoulder influence area can be achieved. The temperature of different areas in the friction welding process can be finely controlled by arranging radially closely packed surrounding flow channels, selectively opening and introducing differential coolants.

[0039] In this embodiment, while achieving gradient cooling in the shoulder influence area, the stirring needle influence area can achieve independent temperature control by adding different coolants, and the temperature of the stirring needle influence area does not decrease, thereby improving the material fusion behavior. The combination of the two can simultaneously enhance the strength of high-strength alloy welds, improve the surface state of the welds, and broaden the friction welding process parameter window, belonging to the field of high-strength aluminum alloy dynamic shoulder or differential stir friction welding technology.

[0040] This embodiment utilizes the radial gradient arrangement of the shoulder area, the multi-cooling flow channel design with independent control of the partitions, and the precise temperature adjustment process of the partition blocks that respond quickly to the local area to obtain a high-strength aluminum alloy stir friction welding structure with a smooth surface and no bran phenomenon.

[0041] On the one hand, this embodiment solves the problem of poor surface quality such as bran to varying degrees caused by overheating in different radii of the shoulder influence zone as heat accumulates during welding during the high-strength aluminum alloy stir friction manufacturing process. On the other hand, it provides a simple and easy local rapid response temperature regulation idea, which can be further promoted and applied to related fields such as stir friction additive and stir friction processing.

[0042] Embodiment 2: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0043] The present embodiment provides a manufacturing method for inhibiting peeling of high-strength aluminum alloy stir friction welding, the manufacturing method: adopts a stirring tool action method of graded cooling and zoned temperature control, wherein a zoned adjustable internal gradient densely packed annularly distributed multi-channel zoned flow diversion cold mode is adopted to cool the shoulder influence area step by step and eliminate the temperature uniformity treatment under the influence of different friction line speeds, and the radial gradient arranged multi-channel can achieve precise and rapid cooling of small blocks in the shoulder influence area by adjusting the type of coolant with different heat capacity in a single channel, differentiating the liquid flow rate or closing some channels. At the same time, the zoned temperature control technology is used to avoid the influence on the stirring needle action area, which can achieve graded cooling of the shoulder influence area without affecting the temperature field of the stirring needle influence area.

[0044] The radial gradient arrangement flow channel design of the stirring tool is conducive to the rapid cooling of the outer area of ​​the shoulder with a higher linear velocity, and the step-by-step cooling of the inner side of the shoulder with a lower linear velocity, so as to achieve controllable adjustment of the temperature gradient of the entire shoulder influence area. In addition, the internal flow channel design is gathered in the central pipe Z1 above the stirring tool. The central pipe is a hollow annular pipe fixed to the central axis of the tool, which can store cooling liquid in advance and does not rotate with the stirring tool. Therefore, the temperature control of the dynamic shoulder or differential shoulder can be achieved. In order to achieve the stirring and cooling of the dynamic shoulder, the central pipe cannot rotate with the shoulder, otherwise it will be entangled. Therefore, all the flow channels are converged at the central pipe, and the central pipe is coaxial with the stirring tool.

[0045] During the friction stir welding process, the peripheral area affected by the shoulder has a large friction linear velocity and generates more friction heat, so the heat accumulation on the peripheral area of ​​the shoulder increases sharply, while the linear velocity on the inner side of the shoulder is small and the heat generation is low. The radial gradient distribution of the zoned controllable shoulder cooling channel can realize the real-time regulation of the micro-area temperature in the area affected by the shoulder. As the heat accumulates, the number of regulated channels increases, thereby effectively avoiding overheating of the peripheral area of ​​the shoulder and separately controlling the opening and closing of the channel near the stirring needle and the flow rate of the coolant, avoiding the temperature in the area affected by the stirring needle from being too low, increasing the plastic flow behavior of the material in the area of ​​the stirring needle, and finally obtaining a high-strength aluminum alloy friction stir welding component with uniform mixing in the stirring area and smooth surface.

[0046] The frictional heat generation is calculated according to formula (1): dq =2 πωμpr 2 dr (1) Among them, q is the heat generation intensity, ω is the angular velocity, μ is the friction coefficient, p is the friction pressure, and r is the radius of a certain position. dq=(*)dr is the calculus formula .

[0047] As above, the calculus formula is r 2, thus determining that the friction heat generated in a unit area of ​​radius is proportional to the cube of the radius. Therefore, the cooling heat flux density needs to be adjusted in the opposite direction, and the coolant flow density must be proportional to the cube of the radius. Therefore, considering the liquid flow density and the space limitation in the stirring tool and the tool strength and stiffness, the design is made in a way that the flow channel volume is proportional to the square of the radius. The key factor in the flow channel volume formula is: r 2 / η , η is the thermal efficiency of the cooling medium. And the flow channel arrangement density is proportional to the radius.

[0048] The shoulder action area adopts a non-uniform multi-cooling flow channel design with radial gradient arrangement, and the shoulder influence area is quickly and locally precisely positioned and gradient temperature controlled by filling the flow channel with differential heat capacity cooling liquid and adjusting the switch of the local flow channel according to local temperature measurement. The manufacturing method specifically includes the following steps: Step S1: installing a stirring tool having a plurality of channel liquid-cooling guide grooves arranged in a radial gradient manner; Step S2: setting a high-strength aluminum alloy welding path; Step S3: determining welding parameters; Step S4: Data model processing, importing the information of step S1 and step S2 into the equipment processing software, and performing high-strength aluminum alloy welding according to the manufacturing parameters determined in step S3; the welding speed is 500~900rpm, and the welding speed is 100~400mm / min.

[0049] Step S5: According to the path planned in step S4, the stirring tool is used to gradually open the cooling channel from the outside to the inside of the shoulder influence area by measuring the temperature in a certain area, ensuring that the temperature of the shoulder influence area does not exceed 450°C, and realizing the temperature uniformity control in the shoulder influence area. At the same time, the stirring needle influence area and the shoulder influence area are controlled separately, and the preheated liquid is passed to realize the differentiated design of the specific heat capacity of the cooling liquid in different flow channels, so that a high-strength aluminum alloy stir friction welding component with fully mixed stirring area and smooth shoulder influence area is prepared.

[0050] During the welding process of high-strength aluminum alloy, there is a phenomenon that the area affected by the stirring needle is not hot enough while the area affected by the shoulder is overheated. Therefore, it is also an extreme manifestation of the different specific heat capacities of the cooling liquids.

[0051] Step S6: As the manufacturing time goes by and heat accumulates, when the manufacturing path reaches more than 200 mm, the two cooling channels R1 and R2 are opened; when the manufacturing length reaches more than 500 mm, the liquid flow channels R1, R2, R3, R4, and R5 are opened.

[0052] In step S4, through multi-channel zoned cooling or heating measures, through zoned cooling of the shoulder influence area and preheating treatment of the stirring needle influence area, the welding parameter window of the new tool for welding high-strength aluminum alloy is widened from the original rotation speed of 600~700rpm to 500~900rpm, and the welding speed is widened from 200mm / min to 100~400mm / min.

[0053] In the step S5, a multi-channel liquid flow circulation cooling measure is adopted, and the cooling speed can be adjusted automatically according to the welding temperature measurement, and the precise temperature measurement and feedback of the shoulder area are used as the control basis. At the initial stage of welding, the welding temperature is relatively low, and the cooling liquid flow can be turned off first. When the welding is about 200mm, the shoulder temperature reaches about 400°C, and 2 to 4 cooling liquid flows are turned on. As the welding distance increases, when the welding distance reaches more than 500mm, 6 to 8 cooling liquid flow channels can be opened to ensure that the temperature of the shoulder affected area is in the range of 400 to 450°C, and at the same time, the stirring needle image area is not affected by cooling.

[0054] Embodiment 3: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0055] The purpose of this embodiment is to provide a manufacturing method for suppressing surface peeling of high-strength aluminum alloy stir friction welding in response to the demand for improving the quality of the friction welding surface of high-strength aluminum alloy and the above-mentioned deficiencies in the prior art.

[0056] In order to achieve the above purpose, this embodiment adopts the following technical solutions: This embodiment provides a manufacturing method for inhibiting peeling of the surface of high-strength aluminum alloy stir friction welding Step S1, installing a stirring tool with radial gradient annular cooling guide grooves: installing the required stirring tool, setting 4 to 10 multi-channel coolant guide grooves on the upper part of the shaft shoulder, and the structural characteristics of the stirring needle part are consistent with those of conventional stir friction welding tools according to the welding material and welding thickness.

[0057] Step S2, setting the high-strength aluminum alloy welding path: according to the welding requirements of the workpiece to be welded, setting the welding path based on the path simulation.

[0058] Step S3, determine welding parameters: The formability of stir friction welding mainly depends on the base material. The stir friction parameters are selected to meet the softening temperature of the base material under the combined action of friction plastic deformation and heat generation, so that it can fully flow around the stirring needle track when it exceeds the yield point, and the temperature of the shoulder influence area is lower than the temperature at which surface peeling occurs. Determine the manufacturing process parameters according to the above material system requirements; The high-strength aluminum alloy in step S3 includes one or more of 2XXX, 5XXX, 6XXX, 7XXX, 8XXX and the above aluminum matrix composite materials reinforced with ceramic particles.

[0059] Step S4, data model processing, import the information of step S1 and step S2 into the equipment processing software, and perform high-strength aluminum alloy welding according to the additive manufacturing parameters determined in step S3. Set v as the welding speed, R as the rotation speed of the stirring tool, D1 as the shoulder diameter, D2 as the stirring needle diameter, and t as the welding thickness. Then plan the manufacturing path and finally export it to a file format that the equipment can recognize.

[0060] Step S5, according to the path planned in step S4, cooperate with the tool of the additive repair equipment, turn on the multi-channel liquid flow filling switch, start the liquid flow cooling of the shoulder affected area, adopt precise temperature monitoring technology, and control the temperature control of the shoulder affected area by feedback adjustment of the number and distribution of cooling channels. Multi-channel liquid flow circulation cooling measures are adopted, and the cooling speed can be adjusted automatically according to the welding temperature measurement. The precise temperature measurement and feedback of the shoulder area are used as the basis for regulation. At the beginning of welding, the welding temperature is low, and the cooling liquid flow can be turned off first. When the welding is about 200mm, the shoulder temperature reaches about 400℃, and 2~4 cooling liquid flows are symmetrically opened. As the welding distance increases, when the welding distance reaches more than 500mm, 4~8 cooling liquid flow channels can be symmetrically opened to ensure that the temperature of the shoulder affected area is in the range of 400~450℃. Finally, a high-strength aluminum alloy stir friction welding component with a smooth shoulder affected area is prepared.

[0061] Figure 3 and Figure 4 It is a three-dimensional schematic diagram of the manufacturing principle of the present invention for suppressing surface peeling of high-strength aluminum alloy stir friction welding. Figure 5 This is a schematic diagram of the effect of multi-cooling channel welding on the improvement of the welding surface quality of 2195 aluminum alloy.

[0062] Compared with the high-strength aluminum alloy friction stir welding technology, in this embodiment, a plurality of liquid flow cooling channels are arranged in the shoulder influence zone of the stirring tool, which can accurately control the temperature of the shoulder influence zone and effectively improve the surface quality of the weld.

[0063] Compared with the traditional high-strength aluminum alloy friction stir welding technology, this embodiment adopts temperature measurement and control and a precise and fast response adjustment method of multiple cooling channels. According to the temperature feedback of the shoulder influence area, the temperature of the shoulder influence area can be fixed and quickly regulated by opening or closing multiple channels in different distribution areas to form a stable shoulder influence area temperature. In addition, since the cooling channels are distributed above the shoulder and the channels are fine, the temperature influence area is limited, and the temperature control of the shoulder influence area can be achieved without affecting the stirring needle influence area.

[0064] Embodiment 4: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0065] This embodiment provides a manufacturing method for suppressing peeling of the surface of a high-strength aluminum alloy stir friction welding, comprising the following steps: Step S1, installing a stirring tool with a liquid cooling guide groove: installing the required stirring tool, setting a 16-way multi-channel cooling liquid guide groove on the upper part of the shaft shoulder, and the structural characteristics of the stirring needle part are consistent with those of a conventional stir friction welding tool according to the welding material and welding thickness; Step S2, setting the high-strength aluminum alloy welding path: according to the welding requirements of the welded parts, take the longitudinal seam friction stir welding of 4mm thick 2195 aluminum alloy tank melon slices as an example, and the total welding length is 2000mm. Use UG to draw the simulated welding path, including the motion trajectory and deflection angle of the stirring needle, compile a program based on the path simulation, set the starting point and the end point, and complete the welding path; Step S3, determining welding parameters: the formability of stir friction welding mainly depends on the substrate. The plastic deformation temperature of stir friction welding of 2195 aluminum alloy is between 400 and 450°C. The stirring tool material is W360. During the preparation process, the substrate undergoes sufficient plastic deformation, and sufficient flow occurs along the shoulder of the stirring tool machine. A good metallurgical bond is formed between the interfaces to be welded, and no obvious stratification occurs in the shoulder influence area and the stirring needle influence area.

[0066] Step S4, data model processing, import the welding path information including the fitting in step S2 into the equipment processing software, and perform high-strength aluminum alloy welding according to the additive manufacturing parameters determined in step S3. Set the welding speed v to 200mm / min, the stirring tool rotation speed R to 500rpm, the shaft shoulder diameter D1 to 20mm, the stirring needle diameter D2 to 4mm, and the welding thickness t to 4mm. Then plan the manufacturing path and finally export it to a file format that can be recognized by the equipment; Step S5, according to the path planned in step S4, cooperate with the tool of the stir friction equipment, turn on the multi-channel liquid flow filling switch, start the liquid flow cooling of the shoulder affected area, adopt precise temperature monitoring technology, and control the temperature control of the shoulder affected area by feedback adjustment of the number and distribution of cooling channels. Adopt multi-channel liquid flow circulation cooling measures, the cooling speed can be adjusted automatically according to the welding temperature measurement, and the precise temperature measurement and feedback of the shoulder area are used as the basis for regulation. Figure 2As shown in the figure, at the initial stage of welding, the welding temperature is low, and the coolant flow can be turned off. When the welding is about 200 mm, the shoulder temperature reaches about 400 ° C, and three coolant flows are turned on: R1, R2, and R3; as the welding distance increases, when the welding distance reaches more than 500 mm, 8 coolant flow channels can be turned on, R1, R2, R3, R4, R5, R6, R7, and R8, to ensure that the temperature of the shoulder affected area is in the range of 400-450 ° C. Finally, a high-strength aluminum alloy friction stir welded component with a smooth shoulder affected area is prepared.

[0067] In this embodiment, the tensile strength of the 2195 aluminum alloy friction stir weld prepared by the traditional stirring tool is 320Mpa, the elongation after fracture is 6%, and the surface has obvious peeling due to the excessive temperature in the shoulder-affected area; the tensile strength of the weld prepared by the sample in this embodiment is 350Mpa and the elongation after fracture is 6%. The weld surface is smooth and flat after temperature control without peeling. This embodiment achieves the improvement of the weld surface quality under the premise of ensuring that the mechanical properties of the high-strength aluminum alloy weld are not reduced.

[0068] In this embodiment, the substrate adopts the precise temperature control and rapid control technology of multiple cooling channels in the shoulder influence area, which can effectively improve the overheating bran phenomenon caused by the excessive temperature in the shoulder influence area on the surface of the high-strength aluminum alloy stir friction weld, and effectively improve the effective thickness and surface quality of the material. At the same time, the shoulder influence area also has a multi-channel liquid flow cooling strategy and rapid response control measures, which can effectively control the temperature influence range, and will not affect the stirring needle shadow area under the premise of ensuring the temperature of the shoulder influence area. Compared with the traditional manufacturing method, this embodiment improves the surface quality of the weld without reducing the mechanical properties of the weld, and avoids the cumbersome subsequent processing steps.

[0069] The present invention can achieve separate control of the shoulder influence zone and the stirring needle influence zone by setting up multiple cooling channels. At the same time, for different areas, different cooling effects can be achieved by controlling whether to introduce cooling medium and controlling the type and flow rate of cooling medium, thereby achieving local temperature control, greatly improving the cooling effect, and improving the accuracy of cooling control.

[0070] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0071] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A stirring device for friction stir welding, characterized in that: include: A stirring shaft shoulder (1) and a stirring needle (2), wherein the stirring needle (2) is arranged at a central axis position of the stirring shaft shoulder (1); A plurality of cooling channels (101) are arranged in the stirring shaft shoulder (1), and the plurality of cooling channels (101) are arranged in a gradient arrangement along the radial direction of the stirring shaft shoulder (1); the depth of the cooling channels (101) extends along the axial direction of the stirring shaft shoulder (1); The plurality of cooling channels (101) are independent of each other, and each cooling channel (101) can be independently fed with a cooling medium; The plurality of cooling channels (101) cover the shaft shoulder influence zone and the stirring needle influence zone of the friction stir weld, and are capable of cooling the shaft shoulder influence zone and the stirring needle influence zone.

2. The stirring device for friction stir welding according to claim 1, characterized in that: In the radial direction of the stirring shaft shoulder (1), the arrangement density of the plurality of cooling channels (101) gradually increases from the inside to the outside.

3. The stirring device for friction stir welding according to claim 1, characterized in that: In the radial direction of the stirring shaft shoulder (1), the widths of the plurality of cooling channels (101) gradually increase from the inside to the outside.

4. The stirring device for friction stir welding according to claim 1, characterized in that: The cooling channel (101) used for cooling the shaft shoulder influence zone and the cooling channel (101) used for cooling the stirring needle influence zone use different cooling media.

5. The stirring device for friction stir welding according to claim 4, characterized in that: In the radial direction of the stirring shaft shoulder (1), the specific heat capacity of the cooling medium in the plurality of cooling channels (101) gradually increases from the inside to the outside.

6. The stirring device for friction stir welding according to claim 1, characterized in that: Each cooling channel (101) is provided with a channel switch; The channel switch is used to control the opening and closing of the cooling channel (101) and / or the flow rate of the cooling medium in the cooling channel (101).

7. The stirring device for friction stir welding according to claim 6, characterized in that: Each of the cooling channels (101) is connected to a cooling medium delivery pipe (3) via a channel switch.

8. The stirring device for friction stir welding according to claim 6, characterized in that: The stirring device further comprises a temperature measuring unit, which is capable of monitoring the temperature of the shaft shoulder influence zone and the stirring needle influence zone; The temperature measurement unit is connected to a control unit, the control unit is connected to the channel switch, and the control unit controls the opening and closing of the channel switch according to the received temperature measurement data.

9. The stirring device for friction stir welding according to claim 1, characterized in that: The cooling channel (101) is a circular cooling channel with a notch (102), and a cooling medium inlet and a medium outlet are formed at the position of the notch (102); In the radial direction of the stirring shaft shoulder (1), the notches (102) of the plurality of cooling channels (101) are arranged in a circumferentially staggered manner from the inside to the outside.

10. A welding method for friction stir welding, characterized in that: The stirring device for friction stir welding according to any one of claims 1 to 9 specifically comprises the following steps: Step S1: installing a stirring device; Step S2: determining welding path and welding parameters; Step S3: stir welding the workpiece by means of a stirring device according to the welding path and welding parameters. During the stirring welding process, the temperature of each area on the stirring shoulder (1) is measured by means of a temperature measuring unit. Based on the temperature measurement data, the opening and closing of the cooling channel (101) and / or the flow rate of the cooling medium in the corresponding area are controlled by means of a control unit.

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