Aluminum alloy full penetration laser welding back forming control method

Abstract

The invention provides an aluminum alloy full penetration laser welding back forming control method. The aluminum alloy full penetration laser welding back forming control method comprises the steps that a joint of two welding plates is pretreated; a liner is provided, a forming groove is formed in the extending direction of the liner, and a through light leakage seam is formed in the groove bottom of the forming groove in the extending direction of the forming groove; the two welding plates are placed on the liner and are in butt joint, and a butt joint seam between the two welding plates is aligned with the light leakage seam; a clamping tool is provided, and the two welding plates are fixed through the clamping tool; and carrying out laser welding along the butt joint seam. By adopting the method, aluminum alloy welding seam back forming can be optimized, the fatigue strength of a connector can be improved, and the defects such as air holes are avoided.

Description

Technical Field

[0001] The invention relates to the field of aluminum alloy laser welding, and in particular to a back forming control method for full penetration laser welding of aluminum alloy. Background Art

[0002] Aluminum alloys are widely used in lightweight manufacturing of large structural parts due to their light weight, high specific strength and strong plasticity, such as rail transportation, ship transportation, aerospace and other fields. When laser penetration welding is used on aluminum alloys, due to the physical properties of liquid aluminum alloys such as low surface tension, low viscosity and strong fluidity, the welding part of the aluminum alloy will form discontinuous weld roots, excessive excess height and uneven burrs during the penetration welding process of aluminum alloys, which seriously affects the joint formation and strength. Summary of the invention

[0003] In view of the shortcomings of the related art mentioned above, an object of the present invention is to provide a back forming control method for full penetration laser welding of aluminum alloy, so as to improve the forming quality during the welding process of aluminum alloy metal.

[0004] To achieve the above-mentioned and other related purposes, the present invention provides a back forming control method for full penetration laser welding of aluminum alloy, the steps of the method comprising:

[0005] Pre-treat the joint of the two welding plates;

[0006] A gasket is provided, a forming groove is provided along the extending direction of the gasket, and a penetrating light leakage slit is provided at the bottom of the forming groove along the extending direction of the forming groove;

[0007] Place two welding plates on the gasket and butt the two welding plates together, with the butt seam between the two welding plates aligned with the light leakage seam;

[0008] A clamping tool is provided, and the two welding plates are fixed with the clamping tool;

[0009] Laser welding is performed along the butt joint.

[0010] Optionally, the step of pre-treating the joint of the two welding plates is: grinding the surface of the welding plates and rinsing them with acetone or alcohol.

[0011] Optionally, the liner is made of stainless steel or high entropy alloy.

[0012] Optionally, the width of the formed groove in the liner is 3-5 mm, and the depth does not exceed 20% of the thickness of the liner.

[0013] Optionally, the cross-sectional shape of the forming groove is set to be an arc shape.

[0014] Optionally, the light leakage slit width is 0.2-0.8 mm.

[0015] Optionally, the assembly gap of the butt joint between the two welding plates is less than 0.5 mm.

[0016] Optionally, the principle of laser welding along the butt joint is to ensure that the laser spot moving position, the butt joint and the light leakage seam are consistent.

[0017] Optionally, when laser welding is performed along the butt joint, the laser beam is set at an angle.

[0018] Optionally, when laser welding is performed along the butt joint, argon gas is used for shielded welding at the rear side of the laser beam advancing direction.

[0019] As described above, the back forming control method of aluminum alloy full penetration laser welding of the present invention has the following beneficial effects: the use of curved forming grooves can significantly optimize the back forming of aluminum alloy welds, which is beneficial to improving the fatigue strength of joints. The use of through-type light leakage grooves maintains the laser penetration welding characteristics and avoids defects such as pores. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a flow chart of a method for controlling back forming of aluminum alloy full penetration laser welding in an embodiment of the present invention.

[0021] Figure 2 Shown is a schematic diagram of laser welding of welding plates in an embodiment of the present invention.

[0022] Figure 3 Shown is a schematic top view of a gasket in an embodiment of the present invention.

[0023] Figure 4 It is a cross-sectional view of the gasket along line AA in an embodiment of the present invention.

[0024] Figure 5 It is a cross-sectional view of the gasket along line BB in an embodiment of the present invention.

[0025] Component number description

[0026] 1. Welding plate; 2. Gasket; 3. Forming groove; 4. Light leakage seam. DETAILED DESCRIPTION

[0027] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0028] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic view is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional space dimensions of length, width and depth should be included.

[0029] For ease of description, spatial relational terms such as "under", "below", "below", "below", "above", "on", etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatial relational terms are intended to include other directions of the device in use or operation in addition to the directions depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intervening layers. As used herein, "between..." means including the end point values.

[0030] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0031] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and therefore the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0032] like Figures 1 to 5 As shown, this embodiment provides a back forming control method for full penetration laser welding of aluminum alloy. The method is used to weld two butted aluminum alloy welding plates 1, and the thickness of the welding plate 1 is 5 to 10 mm. By using this method to perform laser welding on aluminum alloy, the welding quality of the aluminum alloy can be improved.

[0033] The steps of the method include:

[0034] Pre-treating the joints of the two welding plates 1;

[0035] A gasket 2 is provided, a forming groove 3 is formed along the extending direction of the gasket 2, and a penetrating light leakage slit 4 is formed at the bottom of the forming groove 3 along the extending direction of the forming groove 3;

[0036] Place two welding plates 1 on the gasket 2 and butt the two welding plates 1 together, and align the butt joint between the two welding plates 1 with the light leakage seam 4;

[0037] A welding tool is provided, and the two welding plates 1 are fixed by the welding tool;

[0038] Laser welding is performed along the butt joint.

[0039] Specifically, when welding two welding plates 1, the two welding plates 1 need to be pre-treated first. After the welding plates 1 are pre-treated, surface dirt can be removed, thereby improving the welding quality.

[0040] Since aluminum alloy has low surface tension, low viscosity and high fluidity, when laser performs penetration welding on welding plate 1, molten aluminum alloy tends to sag under its own weight, which easily leads to discontinuous weld root, excessive excess height and uneven convex burrs. For this reason, after lining 2 is placed under the two welding plates 1, during the welding process, the forming groove 3 on lining 2 supports the molten aluminum alloy, which can prevent the aluminum alloy from sagging, thereby avoiding discontinuous weld root, excessive excess height and uneven convex burrs. The light leakage slit 4 on lining 2 is used for laser to pass through.

[0041] When the welding plate 1 is placed on the gasket 2 and clamped by a tool, the welding plate 1 can be prevented from being offset, thereby improving the welding quality.

[0042] After the two welding plates 1 are set, laser welding equipment is used to weld along the butt joint.

[0043] By adopting this method, the flow and solidification characteristics of the molten pool at the back of the two welding plates 1 are effectively improved, the weld formation is improved, and the back formation problem of aluminum alloy welding is solved.

[0044] In this embodiment, the steps of pre-treating the joint of the two welding plates 1 are: grinding the surface of the welding plate 1 and washing it with acetone or alcohol.

[0045] Specifically, the rust on the surface of the welding plate 1 can be removed by grinding the welding plate 1. After the surface of the welding plate 1 is ground, the oil stains and metal debris on the surface of the welding plate 1 can be removed by washing with acetone or alcohol.

[0046] The material of the liner 2 is stainless steel or high entropy alloy. In this embodiment, the liner 2 is made of stainless steel.

[0047] In this embodiment, the assembly gap of the butt joint between the two welding plates 1 is less than 0.5 mm.

[0048] In this embodiment, the width of the forming groove 3 in the liner 2 is 3 to 5 mm, and the depth does not exceed 20% of the thickness of the liner 2.

[0049] Specifically, the cross-sectional shape of the forming groove 3 is an arc shape, and the width of the forming groove 3 refers to the widest dimension of the forming groove 3 . Based on the thickness of the liner 2 , the depth of the forming groove 3 in this embodiment is 1 to 2 mm.

[0050] In this embodiment, the width of the light leakage slit 4 is 0.2-0.8 mm. The light leakage slit 4 is located at the bottom of the arc groove of the forming groove 3, and the light leakage slit 4 penetrates the liner 2. When laser welding is performed, the laser beam can pass through the light leakage slit 4, and the light leakage slit 4 plays a role of giving way.

[0051] In this embodiment, the clamping tool is a high temperature screw. After the welding plate 1 is placed on the gasket 2, a plurality of high temperature screws arranged at equal intervals are arranged on both sides of each welding plate 1 for fixing. Among them, the high temperature screw closest to the butt joint is located at one sixth of the welding plate 1.

[0052] In this embodiment, the principle of laser welding along the butt joint is to ensure that the laser spot moving position, the butt joint and the light leakage gap 4 are consistent.

[0053] When the laser spot moves in the same position as the joint, the two welding plates 1 can be accurately welded together. At the same time, the laser spot moves in the same position as the light leakage seam 4. At this time, the laser can be prevented from melting the gasket 2 and welding the welding plate 1 and the gasket 2 together.

[0054] In this embodiment, in order to avoid adverse effects of laser reflection on the laser equipment during laser welding, the laser beam is tilted when laser welding is performed along the joint, that is, the laser equipment needs to be tilted at a certain angle.

[0055] In this embodiment, when laser welding is performed along the butt joint, argon gas is used for shielded welding at the rear side of the laser beam's advancing direction. As an inert gas, argon gas can effectively isolate oxygen, nitrogen and hydrogen in the air, preventing weld oxidation and pore formation. During the laser welding process, argon gas can form a protective gas hood to protect the molten pool from interference from external gases, thereby ensuring welding quality. In addition, during laser welding, the plasma cloud above the molten pool will scatter the laser, affecting the penetration depth and weld strength. Argon gas can disperse the plasma cloud through the blowing effect, increase the molten pool's absorption of laser energy, and thus improve welding efficiency and penetration depth.

[0056] It can be understood that when welding welding plates 1 of different thicknesses, the appropriate laser power and welding speed are matched according to the working conditions. For example, in this embodiment, the welding plate 1 is made of aluminum-magnesium alloy, with a size of 200mm×100mm×10mm, and the design size of the liner 2 is 300mm×100mm×10mm, wherein the width of the forming groove 3 is 5mm, the depth is 2mm, and the width of the through-type light leakage seam 4 is 0.5mm. During the welding process, the laser power is 6.6kW and the ring laser power is 1.5kW, the welding speed is 2m / min, the laser head is tilted 4°, 0 defocus is used, the shielding gas is argon, the flow rate of argon is set to 20L / min, and it is placed at the rear side of the molten pool at an angle of 45° for protection.

[0057] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for controlling back forming of full penetration laser welding of aluminum alloy, characterized in that: The steps of the method include: Pre-treat the joint of the two welding plates; A gasket is provided, a forming groove is provided along the extending direction of the gasket, and a penetrating light leakage slit is provided at the bottom of the forming groove along the extending direction of the forming groove; Place two welding plates on the gasket and butt the two welding plates together, with the butt seam between the two welding plates aligned with the light leakage seam; A clamping tool is provided, and the two welding plates are fixed with the clamping tool; Laser welding is performed along the butt joint.

2. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: The steps of pre-treating the joints of the two welding plates are: grinding the surfaces of the welding plates and washing them with acetone or alcohol.

3. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: The liner is made of stainless steel or high entropy alloy.

4. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: The width of the formed groove in the liner is 3 to 5 mm, and the depth does not exceed 20% of the thickness of the liner.

5. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: The cross-sectional shape of the forming groove is set to be an arc shape.

6. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: The width of the light leakage gap is 0.2 to 0.8 mm.

7. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: The assembly gap of the butt joint between the two welding plates is less than 0.5 mm.

8. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: The principle of laser welding along the butt joint is to ensure that the laser spot moving position, the butt joint and the light leakage seam are consistent.

9. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: When laser welding is performed along the butt joint, the laser beam is arranged at an angle.

10. The aluminum alloy full penetration laser welding back forming control method according to claim 1, characterized in that: When laser welding is performed along the butt joint, argon gas is used for shielded welding at the rear side of the laser beam's advancing direction.

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