A 5A06 aluminum alloy weld structure and its preparation method

Abstract

This invention discloses a 5A06 aluminum alloy weld structure, in which the main load-bearing weld is located inside the cavity, and the auxiliary weld is located outside the cavity. The auxiliary weld is shaped by grinding. This invention also discloses a method for preparing the aforementioned 5A06 aluminum alloy weld structure. This invention enables the welded cavity structure to achieve excellent mechanical properties and appearance precision of the welded joint, meeting the 5A06 aluminum alloy welding forming precision requirements for complex multi-sloping cavity structures in typical marine equipment, and solving the technical problem of strength loss after grinding in traditional 5A06 aluminum alloy welded joints.

Description

Technical Field

[0001] This invention pertains to welding, and particularly relates to a 5A06 aluminum alloy weld structure and its preparation method. Background Technology

[0002] 5A06 aluminum alloy, with Mg as the main additive element, is characterized by low density, high strength, strong resistance to seawater corrosion, excellent weldability, and good polishability. It is widely used in shipbuilding, aviation, and aerospace, and has become a primary material for marine equipment production. For cavity structures such as columns in typical marine equipment, after welding, there is excess weld height at the weld joint, making it difficult to control the appearance. This not only affects the overall structural dimensional accuracy of the equipment but also leaves stress concentrations and welding defects. Therefore, for equipment with strict shape requirements, most exposed weld joints must be ground to meet actual usage requirements. However, there is a difference in the mechanical properties of traditional 5A06 aluminum alloy weld joints before and after grinding; the tensile properties before grinding are better than those after grinding. This is mainly because the weld area increases the load-bearing area and can withstand higher loads. To ensure the strength of 5A06 aluminum alloy weld joints while achieving good shape accuracy and improving the internal and external welding quality and pass rate of products, it is necessary to design a new 5A06 aluminum alloy weld joint structure and its preparation method. Summary of the Invention

[0003] In view of the high precision requirements for welding and forming of 5A06 aluminum alloy in the complex multi-sloping cavity structure of typical marine equipment, and in order to obtain good mechanical properties and appearance accuracy of the welded joint and solve the technical problem of strength loss after grinding of traditional 5A06 aluminum alloy welded joints, the purpose of this invention is to provide a 5A06 aluminum alloy weld structure and its preparation method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A 5A06 aluminum alloy weld structure, wherein the main load-bearing weld is located inside the cavity, and the auxiliary weld is located outside the cavity. The auxiliary weld is ground and shaped.

[0006] The method for preparing the 5A06 aluminum alloy weld structure:

[0007] Before welding, a V-shaped groove gap, blunt edge and angle are set on the inside of the joint of the workpiece; burrs and oxide film within 50mm on both sides of the workpiece surface are removed mechanically, and then the cleaned surface is decontaminated by chemical means, and then the workpiece surface is dried.

[0008] During welding, the workpieces are positioned according to the pre-set angle between them. Under the on-site welding environment, the workpieces are preheated. Then, the main weld inside the cavity is horizontally welded according to the welding process parameters. The weld layers are then cleaned and stress-relieved. After the main weld is completed, the root is thoroughly cleaned in the reverse direction. Horizontal auxiliary welding of the outer weld is performed on the outside of the cavity. After the auxiliary weld is completed, it is ground and shaped.

[0009] The relationship between the V-groove gap, blunt edge, angle, and workpiece thickness is shown in the table below:

[0010]

[0011] When positioning according to the preset angle between workpieces, clean auxiliary tools such as welding fixtures and backing plates are used.

[0012] The on-site welding environment conditions are: wind speed not exceeding 1.5 m / s, relative humidity not exceeding 70%, and temperature not lower than 5℃.

[0013] The temperature for preheating the welded area of ​​the workpiece is 120℃±30℃.

[0014] The welding process parameters are as follows: ① MIG welding: welding current DC 220A, arc voltage 23V, welding speed 18cm / min; ② TIG welding: welding current AC 295A, arc voltage 13V, welding speed 20cm / min; ③ Argon purity not less than 99.99%.

[0015] The welding wire used is 5A06 or ALMg6%. The welding wire should be cleaned and dried before use.

[0016] The cleaned workpiece and welding wire were welded within 4 hours.

[0017] The 5A06 aluminum alloy weld structure and its preparation method proposed in this invention enable the welded cavity structure to achieve excellent mechanical properties and appearance precision of the welded joint, meeting the welding forming precision requirements of 5A06 aluminum alloy for complex multi-sloping cavity structures in typical marine equipment. It also solves the technical problem of strength loss after grinding traditional 5A06 aluminum alloy welded joints. Testing shows that the welded joint formed using the 5A06 aluminum alloy weld structure preparation method proposed in this invention has a tensile strength of not less than 300 MPa, reaching more than 95% of the specified tensile strength of the 5A06 base material. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the aluminum alloy cavity structure.

[0019] Figure 2 for Figure 1 View from AA.

[0020] Figure 3 for Figure 2 Enlarged view of section I in the middle.

[0021] Figure 4 This is a schematic diagram of the forming process of an aluminum alloy welded joint.

[0022] Figure 1 , Figure 2 In the diagram, 1-aluminum alloy cavity structure, 2-workpiece I, 3-workpiece II, 4-main weld, 5-outer weld, a-gap, p-blunt edge, α-angle, T-plate thickness. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] like Figure 1 As shown, the aluminum alloy cavity structure 1 is formed by welding together multiple workpieces made of 5A06 material, requiring high overall structural strength and precision in appearance forming. For example... Figure 2 , Figure 3 As shown, taking the weld between workpiece I2 and workpiece II3 as an example, a technical solution of "main weld 4 internal load-bearing + external weld 5 auxiliary shaping" is adopted. The load-bearing main weld 4 is placed inside the aluminum alloy cavity structure 1 to ensure the strength of the welded structure. After the main weld 4 is welded and the root is cleaned in the reverse direction, the external weld 5 is welded on the outside of the aluminum alloy cavity structure 1. After the welding is completed, the external weld 5 is ground to form an edge to ensure the accuracy of the appearance. Other workpieces are welded and shaped according to the above technical solution, and finally a stable and beautiful closed structure is formed.

[0025] like Figure 4 As shown, the forming process of aluminum alloy welded joints is as follows:

[0026] Before welding, according to the pre-set angle requirements between workpiece I2 and workpiece II3 and the V-groove requirements for different plate thicknesses, a V-groove gap a, a blunt edge p, and an angle α are respectively set on the inner side of the joint between workpiece I2 and workpiece II3; the relationship between the V-groove gap, blunt edge, angle, and workpiece thickness is shown in the table below:

[0027]

[0028] Then, mechanical methods are used to remove burrs and oxide film within 50mm on both sides of the surfaces of workpieces I2 and II3. Following this, chemical methods are used to clean the surfaces. After the surfaces of workpieces I2 and II3 are dry, they proceed to the welding process. The welding wire used is of the same composition as the base metal (5A06) or a similar material (ALMg6%). The welding wire should be cleaned and dried before use. Welding should be completed within 4 hours of cleaning the workpieces and welding wire to avoid the formation of new oxide film.

[0029] During welding, cleaned welding fixtures, backing plates, and other auxiliary tools are used. Positioning is performed according to the pre-set angle between workpieces I2 and II3. The on-site welding environment is controlled and confirmed. The on-site welding environment conditions are: wind speed not exceeding 1.5 m / s, relative humidity not exceeding 70%, and temperature not lower than 5℃. Preheating treatment is applied to the welding areas of workpieces I2 and II3 at a temperature of 120℃±30℃. Appropriate process parameters are selected according to different welding methods: ①MIG welding: welding current DC 220A, arc voltage 23V, welding speed 18cm / min; ②TIG welding: welding current AC 295A, arc voltage 13V, welding speed 20cm / min; ③argon purity not less than 99.99%. The inner main weld 4 is welded horizontally, ensuring full penetration. For the main weld 4, which has a large weld pool and requires multi-layer welding, interlayer cleaning and stress relief treatment should be performed promptly during the welding process. After the main weld 4 is completed, a thorough reverse root cleaning is performed to form a bevel angle α. Horizontal auxiliary welding of the outer weld 5 is then performed on the outside of the aluminum alloy cavity structure 1. After welding, the outer weld 5 is ground to form an edge, ensuring the appearance and forming accuracy of the aluminum alloy cavity structure 1. All aluminum alloy welded joints must be welded horizontally during forming.

[0030] The following are some specific examples:

[0031] Example 1: The workpiece thickness is 8mm. Before welding, according to the pre-set forming angle requirements between workpieces I2 and II3, V-shaped bevels are machined on the inner side of the joint between workpieces I2 and II3, ensuring that the bevel angle α is 70º, the gap a is 2mm, and the blunt edge p is 2mm. Burrs and oxide films within a range of at least 50mm on both sides of the surfaces of workpieces I2 and II3 are removed mechanically. Then, the cleaned surfaces are chemically treated for decontamination. Welding is only permitted after the surfaces of workpieces I2 and II3 are dry. The welding wire uses 5A06 or a similar material (ALMg6%) with the same composition as the base metal. The welding wire should be cleaned and dried before use. Welding should be completed within 4 hours after cleaning of the workpiece and welding wire to avoid the formation of new oxide films.

[0032] Example 2: The workpiece thickness is 12mm. Before welding, according to the pre-set angle requirements between workpieces I2 and II3, V-shaped bevels are machined on the inner side of the joint between workpieces I2 and II3, ensuring a bevel angle α of 80º, a gap a of 2mm, and a blunt edge p of 2mm. Burrs and oxide films within a range of at least 50mm on both sides of the surfaces of workpieces I2 and II3 are removed mechanically. Then, the cleaned surfaces are chemically treated for decontamination. Welding is only permitted after the surfaces of workpieces I2 and II3 are dry. The welding wire uses 5A06 or a similar material (ALMg6%) with the same composition as the base metal. The welding wire should be cleaned and dried before use. Welding of the cleaned workpiece and welding wire should be completed within 4 hours to avoid the formation of new oxide films.

[0033] Example 3: The workpiece thickness is 18mm. Before welding, according to the pre-set forming angle requirements between workpieces I2 and II3, V-shaped bevels are machined on the inner side of the joint between workpieces I2 and II3, ensuring that the bevel angle α is 80º, the gap a is 4mm, and the blunt edge p is 3mm. Burrs and oxide films within a range of at least 50mm on both sides of the surfaces of workpieces I2 and II3 are removed mechanically. Then, the cleaned surfaces are chemically treated for decontamination. Welding is only permitted after the surfaces of workpieces I2 and II3 are dry. The welding wire uses 5A06 or a similar material (ALMg6%) with the same composition as the base metal. The welding wire should be cleaned and dried before use. The cleaned workpiece and welding wire should be welded within 4 hours to avoid the formation of new oxide films.

[0034] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A 5A06 aluminum alloy weld structure, characterized in that: The main weld is located inside the cavity, while the auxiliary weld is located outside the cavity. The auxiliary weld is ground and shaped. The method for preparing the 5A06 aluminum alloy weld structure is as follows: Before welding, a V-shaped groove gap, blunt edge and angle are set on the inside of the joint of the workpiece; burrs and oxide film within 50mm on both sides of the workpiece surface are removed mechanically, and then the cleaned surface is decontaminated by chemical means, and then the workpiece surface is dried. During welding, the workpieces are positioned according to the pre-set angle between them. Under the on-site welding environment, the workpieces are preheated. Then, the main weld inside the cavity is horizontally welded according to the welding process parameters. The weld layers are then cleaned and stress-relieved. After the main weld is completed, the root is thoroughly cleaned in the reverse direction. The external weld is horizontally auxiliary welded on the outside of the cavity. After the auxiliary weld is completed, it is ground and shaped. The relationship between the V-groove gap, blunt edge, angle, and workpiece thickness is shown in the table below: 。 2. The 5A06 aluminum alloy weld structure as described in claim 1, characterized in that: When positioning according to the preset angle between workpieces, clean auxiliary tools such as welding fixtures and backing plates are used.

3. The 5A06 aluminum alloy weld structure as described in claim 1, characterized in that: The on-site welding environment conditions are: wind speed not exceeding 1.5 m / s, relative humidity not exceeding 70%, and temperature not lower than 5℃.

4. The 5A06 aluminum alloy weld structure as described in claim 1, characterized in that: The temperature for preheating the welded area of ​​the workpiece is 120℃±30℃.

5. The 5A06 aluminum alloy weld structure as described in claim 1, characterized in that: The welding process parameters are as follows: ① MIG welding: welding current DC 220A, arc voltage 23V, welding speed 18cm / min; ② TIG welding: welding current AC 295A, arc voltage 13V, welding speed 20cm / min; ③ Argon purity not less than 99.99%.

6. The 5A06 aluminum alloy weld structure as described in claim 1, characterized in that: The welding wire used is 5A06 or ALMg6%. The welding wire should be cleaned and dried before use.

7. The 5A06 aluminum alloy weld structure as described in claim 6, characterized in that: The cleaned workpiece and welding wire were welded within 4 hours.

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