A kind of induction brazing equipment and welding method suitable for thin-walled aluminum dense micro-channel

Abstract

The present invention discloses an induction brazing device and welding method suitable for thin-walled aluminum dense microchannels, belonging to the field of welding technology. It includes upper and lower annular induction coils and an induction coil position adjustment mechanism. The lower annular induction coil is fixedly connected to the induction coil position adjustment mechanism. During welding, the upper annular induction coil is located directly above the lower annular induction coil. The induction coil position adjustment mechanism can adjust the displacement of the lower annular induction coil in the vertical direction. The middle of the lower annular induction coil is a horizontal section, and both ends are tilted downward. The cross-sectional shapes of the upper annular induction coil and the lower annular induction coil correspond to the cross-sectional shapes of the pre-welded manifolds, and gaps are left between the pre-welded manifolds. The present invention is suitable for the welding of thin-walled aluminum dense microchannels, ensures the quality of the weld, improves the welding efficiency, and has the advantages of complete brazing seam filling and bright brazing seam on both sides.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to an induction brazing device and a welding method suitable for thin-walled aluminum dense micro-channels. Background Art

[0002] The dense micro-channel structure of the light metal cabin is made of aluminum and has a thin-walled structure. During the welding process, it is very easy for the thin-walled structure to melt due to overheating. The temperature accumulation during continuous welding will also cause other tube walls or square tube structures to overheat and melt. Therefore, there are problems such as difficulty in brazing, low success rate of welding multiple welds at one time, and difficulty in quantifying key control factors in the manufacturing process. Summary of the invention

[0003] Based on the above shortcomings, the purpose of the present invention is to provide an induction brazing device and welding method suitable for thin-walled aluminum dense microchannels, which is suitable for the welding of thin-walled aluminum dense microchannels and meets the needs of rapid manufacturing of large-area microchannel cooling systems for high Mach aircraft.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an induction brazing device suitable for thin-walled aluminum dense microchannels, comprising an upper annular induction coil, a lower annular induction coil and an induction coil position adjustment mechanism, wherein the lower annular induction coil is fixedly connected to the induction coil position adjustment mechanism, and during welding, the upper annular induction coil is located directly above the lower annular induction coil, and the induction coil position adjustment mechanism can adjust the displacement of the lower annular induction coil in the vertical direction; the middle of the lower annular induction coil is a horizontal section, and both ends are inclined downward, and the cross-sectional shapes of the upper annular induction coil and the lower annular induction coil correspond to the cross-sectional shapes of the pre-welded manifold, and gaps are left between the upper annular induction coil and the pre-welded manifold.

[0005] Furthermore, both ends of the lower annular induction coil are U-shaped and tilted downward.

[0006] Furthermore, the induction coil position adjustment mechanism includes a lead screw, a support frame, a bearing and a horizontal support rod. The outer ring and the inner ring of the bearing are tightly connected in the axial direction without relative displacement, and can rotate relative to each other in the radial direction. The middle section of the support frame is an open structure with one side concave. The lead screw passes through the center of the upper and lower planes of the support frame and is threadedly connected thereto. The upper end of the lead screw is a rocker structure. The bearing is located in the opening structure. The middle section of the lead screw is fixedly connected to the inner ring of the bearing, and the outer ring of the bearing is fixedly connected to the lower annular induction coil through a horizontal support rod.

[0007] Furthermore, the lower annular induction coil is a water-cooled temperature-adjustable induction coil, which adopts a copper tube with a diameter of 4-10 mm and a wall thickness of 1-3 mm; the upper annular induction coil is a water-cooled temperature-adjustable induction coil, which adopts a copper tube with a diameter of 1-4 mm and a wall thickness of 0.2-1 mm.

[0008] Furthermore, the gap is 2mm-15mm.

[0009] Another object of the present invention is to provide a method for induction brazing of thin-walled aluminum dense micro-channels obtained by the brazing equipment as described above, the steps of which are as follows:

[0010] Step S1, inserting the dense microchannel row tube into the cavity of the manifold with a clearance fit between the two; placing the manifold at the center position inside the upper annular induction coil and the lower annular induction coil;

[0011] Step S2, apply annular solder to the weld, start the power supply of the lower annular induction coil first, select high-power pulse adjustable AC for welding, quickly heat the front and rear sides of the manifold, and fine-tune the upper and lower positions of the lower annular induction coil through the induction coil position adjustment mechanism to control the heat input position; when the annular solder is observed to melt, immediately turn off the power supply of the lower annular induction coil, and start the power supply of the upper annular induction coil, select low-power pulse adjustable AC for welding, so that the temperature of the annular solder can rise slightly, until the annular solder is observed to be completely melted and spread, and after welding, the soldering seam is completely filled, both sides of the soldering seam are bright, the soldering angle transition is rounded, and the pipeline is not blocked.

[0012] Furthermore, the power of the lower ring-shaped induction coil can be adjusted in a range of 20-40 kW, and the power of the upper ring-shaped induction coil can be adjusted in a range of 5-15 kW.

[0013] Furthermore, the wall thickness of the dense microchannel tube is in the range of 0.1-0.6 mm.

[0014] Furthermore, the wall thickness of the manifold is in the range of 1-5 mm, and the matching clearance between the dense microchannel row tube and the manifold is in the range of 0.1-0.5 mm.

[0015] Furthermore, the annular solder is aluminum-silicon solder or aluminum-copper solder.

[0016] The beneficial effects of the present invention are as follows: the present invention is suitable for the welding of thin-walled aluminum dense micro-channels, ensures the quality of the weld, improves the welding efficiency, has the advantages of complete brazing seam filling and bright both sides of the brazing seam, has no destructive defects such as cracks and unfilled brazing seams, has good contact between the brazing material and the parent materials on both sides, has a rounded brazing angle transition, and has no pipeline blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of thin-walled aluminum dense micro-channel induction brazing welding;

[0018] Figure 2 It is a partial structural schematic diagram of thin-walled aluminum dense micro-channel induction brazing welding;

[0019] Figure 3 It is a top view of thin-walled aluminum dense micro-channel row pipe and manifold;

[0020] Figure 4 yes Figure 3 A partial enlarged view of

[0021] Figure 5 It is a schematic diagram of the post-weld weld formation of thin-walled aluminum dense micro-channel induction brazing;

[0022] Figure 6 It is a schematic diagram of the weld structure after welding of thin-walled aluminum dense microchannel induction brazing. DETAILED DESCRIPTION

[0023] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0024] Example 1

[0025] like Figure 1As shown, an induction brazing device suitable for thin-walled aluminum dense microchannels includes an upper annular induction coil 6, a lower annular induction coil 1 and an induction coil position adjustment mechanism 2, wherein the lower annular induction coil 1 is fixedly connected to the induction coil position adjustment mechanism 2, and during welding, the upper annular induction coil 6 is located directly above the lower annular induction coil 1, and the induction coil position adjustment mechanism 2 can adjust the displacement of the lower annular induction coil 1 in the vertical direction; the middle of the lower annular induction coil 1 is a horizontal section, and both ends are U-shaped and tilted downward, and the cross-sectional shapes of the upper annular induction coil 6 and the lower annular induction coil 1 correspond to the cross-sectional shapes of the pre-welded manifold 4, and a gap of 2mm-15mm is left between the pre-welded manifold 4. The induction coil position adjustment mechanism 2 includes a lead screw 201, a support frame 202, a bearing 204 and a horizontal support rod 205. The outer ring and the inner ring of the bearing 204 are tightly connected in the axial direction without relative displacement, and can rotate relatively in the radial direction; the middle section of the support frame 202 is an open structure with one side concave, the lead screw 201 passes through the center of the upper and lower planes of the support frame 202 and is threadedly connected thereto, the upper end of the lead screw 201 is a rocker structure 203, the bearing 204 is located in the opening structure, the middle section of the lead screw 201 is fixedly connected to the inner ring of the bearing 204, and the outer ring of the bearing 204 is fixedly connected to the lower annular induction coil 1 through the horizontal support rod 205, and the displacement of the lower annular induction coil 1 can be changed in the vertical direction by rotating the rocker structure 203. The lower annular induction coil 1 is a water-cooled temperature-adjustable induction coil, which adopts a copper tube with a diameter of 4-10 mm and a wall thickness of 1-3 mm; the upper annular induction coil 6 is a water-cooled temperature-adjustable induction coil, which adopts a copper tube with a diameter of 1-4 mm and a wall thickness of 0.2-1 mm.

[0026] Example 2

[0027] This embodiment adopts the brazing equipment of Embodiment 1 to obtain an induction brazing method suitable for thin-walled aluminum dense micro-channels, and the steps are as follows:

[0028] Step S1: Figure 2 As shown, the dense microchannel row tube 3 is inserted into the cavity of the manifold 4, and there is a clearance fit between the two, and the fit clearance is 0.1-0.5mm; the manifold 4 is placed at the center position inside the upper annular induction coil 6 and the lower annular induction coil 1, and the wall thickness range of the dense microchannel row tube 3 is 0.1-0.6mm, and the wall thickness range of the manifold 4 is 1-5mm; the top view and partial enlarged view of the thin-walled aluminum dense microchannel row tube 3 and the manifold 4 are shown in Figure 3-4 As shown;

[0029] Step S2, apply annular solder 5 on the weld, use aluminum silicon solder or aluminum copper solder, start the power supply of the lower annular induction coil 1 first, select high-power pulse adjustable AC for welding, the power adjustable range is 20-40kW, the purpose of using high power is to allow the manifold 4 to quickly reach a relatively high temperature, improve welding efficiency, and at the same time, the front and back heat transfer makes the heat transfer slow, so that the solder will not melt and wet quickly, and quickly heat the front and back sides of the manifold 4, and fine-tune the upper and lower positions of the lower annular induction coil 1 through the induction coil position adjustment mechanism 2 to control the heat input position; When the melting of the annular solder 5 is detected, the power supply of the lower annular induction coil 1 is immediately turned off, and the power supply of the upper annular induction coil 6 is started. A low-power pulse adjustable AC is selected for welding. The adjustable power range is 5-15kW. Switching to a low-power coil makes it difficult for heat to dissipate, and the temperature can be increased slightly until the solder is completely spread and wetted, so that the welding effect is better and the welding quality is better. The temperature of the annular solder 5 can be increased slightly until the annular solder 5 is observed to be completely melted and spread. After welding, the soldering seam is completely filled, the two sides of the soldering seam are bright, the soldering angle transition is rounded, and the pipeline is not blocked.

[0030] Example 3

[0031] The structure of this embodiment is the same as that of embodiment 1, except that the lower annular induction coil 1 is a copper tube with a diameter of 7 mm, a wall thickness of 1.5 mm, and a power output of 35 kW; the upper annular induction coil 6 is a copper tube with a diameter of 3.5 mm, a wall thickness of 0.4 mm, and a power output of 12 kW. Both induction coils can be internally circulated with cooling water to control the welding temperature. The wall thickness of the dense microchannel row tube 3 brazed in this embodiment is 0.25 mm, the clearance fit size between the dense microchannel row tube 3 and the manifold 4 is 0.25 mm, and the wall thickness range of the manifold 4 is 3 mm. The annular brazing material 5 is an aluminum-copper brazing material. A gap of 6 mm is left between the lower annular induction coil 1 and the upper annular induction coil 6 and the manifold 4.

[0032] Example 4

[0033] The structure of this embodiment is the same as that of embodiment 1, except that the lower annular induction coil 1 is a copper tube with a diameter of 6 mm, a wall thickness of 1 mm, and a power output of 30 kW; the upper annular induction coil 6 is a copper tube with a diameter of 3 mm, a wall thickness of 0.3 mm, and a power output of 10 kW. Both induction coils can be internally circulated with cooling water to control the welding temperature. The wall thickness of the dense microchannel tubes 3 brazed in this embodiment is 0.2 mm, the clearance fit size between the dense microchannel tubes 3 and the manifold 4 is 0.2 mm, and the wall thickness range of the manifold 4 is 3 mm. The annular brazing material 5 is aluminum silicon brazing material. A gap of 5 mm is left between the lower annular induction coil 1 and the upper annular induction coil 6 and the manifold 4. The schematic diagram of the weld formation after welding is shown in the figure. Figure 5 As shown in the figure, the heating during welding is relatively uniform, the brazing seam is completely filled, both sides of the brazing seam are very bright, there are no cracks, unfilled and other destructive defects, the brazing material is in good contact with the base material on both sides, the brazing angle transition is rounded, and the pipeline is not blocked. Figure 6 As shown in the figure, the microstructure shows that the specimen is in a state of penetration, and the weld structure is mainly composed of a eutectic structure formed by fine needle-like Si and α (Al), in which the primary α (Al) structure is discretely distributed. The welding is performed by local heating with a high-frequency induction coil, which ensures the weld quality and welding efficiency.

Claims

1. A method for induction brazing of thin-walled aluminum dense microchannels, the equipment used comprises an upper annular induction coil (6), a lower annular induction coil (1) and an induction coil position adjustment mechanism (2), the lower annular induction coil (1) is fixedly connected to the induction coil position adjustment mechanism (2), during welding, the upper annular induction coil (6) is located directly above the lower annular induction coil (1), and the induction coil position adjustment mechanism (2) can adjust the displacement of the lower annular induction coil (1) in the vertical direction; the middle of the lower annular induction coil (1) is a horizontal section, and both ends are inclined downward, the cross-sectional shapes of the upper annular induction coil (6) and the lower annular induction coil (1) correspond to the cross-sectional shapes of the pre-welded manifold (4), and there is a gap between the upper annular induction coil (6) and the lower annular induction coil (1), characterized in that: The steps are as follows: Step S1, inserting the dense microchannel array tube (3) into the cavity of the manifold (4), with a clearance fit between the two; placing the manifold (4) at the center position inside the upper annular induction coil (6) and the lower annular induction coil (1); Step S2, applying an annular solder (5) to the weld, first starting the power supply of the lower annular induction coil (1), selecting a high-power pulse adjustable alternating current for welding, rapidly heating the front and rear sides of the manifold (4), and finely adjusting the upper and lower positions of the lower annular induction coil (1) through the induction coil position adjustment mechanism (2) to control the heat input position; When the annular solder (5) is observed to be melting, the power supply of the lower annular induction coil (1) is immediately turned off, and the power supply of the upper annular induction coil (6) is started. A low-power pulse adjustable alternating current is selected for welding, so that the temperature of the annular solder (5) can be slightly increased until the annular solder (5) is observed to be completely melted and spread. After welding, the soldering seam is completely filled, both sides of the soldering seam are bright, the soldering angle transition is rounded, and the pipeline is not blocked.

2. The induction brazing method for thin-walled aluminum dense microchannel according to claim 1, characterized in that: The power of the lower ring-shaped induction coil (1) can be adjusted in a range of 20-40 kW, and the power of the upper ring-shaped induction coil (6) can be adjusted in a range of 5-15 kW.

3. The induction brazing method for thin-walled aluminum dense microchannel according to claim 1, characterized in that: The wall thickness of the dense microchannel tube (3) is in the range of 0.1-0.6 mm.

4. The induction brazing method for thin-walled aluminum dense microchannel according to claim 1, characterized in that: The wall thickness of the manifold (4) is in the range of 1-5 mm, and the matching clearance between the dense microchannel tubes (3) and the manifold (4) is in the range of 0.1-0.5 mm.

5. The induction brazing method for thin-walled aluminum dense microchannel according to claim 1, characterized in that: The annular solder (5) is aluminum-silicon solder or aluminum-copper solder.

6. The induction brazing method for thin-walled aluminum dense micro-channel according to claim 1, characterized in that: The two ends of the lower annular induction coil (1) are U-shaped and tilted downward.

7. The induction brazing method for thin-walled aluminum dense micro-channel according to claim 1, characterized in that: The induction coil position adjustment mechanism (2) comprises a lead screw (201), a support frame (202), a bearing (204) and a horizontal support rod (205); the outer ring and the inner ring of the bearing (204) are tightly connected in the axial direction without relative displacement and can rotate relative to each other in the radial direction; the middle section of the support frame (202) is an open structure with one side concave; the lead screw (201) passes through the center of the upper and lower planes of the support frame (202) and is threadedly connected thereto; the upper end of the lead screw (201) is a rocker structure (203); the bearing (204) is located in the open structure; the middle section of the lead screw (201) is fixedly connected to the inner ring of the bearing (204); and the outer ring of the bearing (204) is fixedly connected to the lower annular induction coil (1) via the horizontal support rod (205).

8. A method for induction brazing of thin-walled aluminum dense micro-channels according to claim 1, 2, 6 or 7, characterized in that: The lower ring-shaped induction coil (1) is a water-cooled temperature-adjustable induction coil, which adopts a copper tube with a diameter of 4-10 mm and a wall thickness of 1-3 mm; the upper ring-shaped induction coil (6) is a water-cooled temperature-adjustable induction coil, which adopts a copper tube with a diameter of 1-4 mm and a wall thickness of 0.2-1 mm.

9. The induction brazing method for thin-walled aluminum dense microchannel according to claim 1, characterized in that: The gap is 2mm-15mm.

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