A welding method for a high-strength aluminum alloy plate for a ship and an aluminum alloy mooring rail

Abstract

The application discloses a welding method for a high-strength aluminum alloy plate for a ship and an aluminum alloy mooring rail, and comprises the following steps: (1) processing a V-shaped groove on the high-strength aluminum alloy plate for the ship; processing a V-shaped groove on the mooring rail by chamfering; (2) the welding position is flat butt joint, and the welding bead is double-sided welding; first, performing semi-automatic MIG welding on the front side, welding current is 70-90 A, and welding voltage is 15-18 V; then, performing automatic MIG welding on the back side, welding current is 120-160 A, and welding voltage is 19-21 V. The welding process method can obtain a welding seam with a good surface, no pores and no cracks, guarantees that the welded joint has good tensile property and bending property, and realizes high-efficiency connection of the high-strength aluminum alloy material for the ship and the aluminum alloy mooring rail.

Description

Technical Field

[0001] The present invention belongs to the technical field of marine aluminum alloy welding, and particularly relates to a metal inert gas (MIG) welding method for a marine high-strength aluminum alloy plate and an aluminum alloy mooring rail. Background Art

[0002] In recent years, with the rapid development of aluminum alloy technology, China has successfully developed a high-strength aluminum alloy for marine applications with a tensile strength exceeding 390 MPa. Using appropriate welding processes, the tensile strength of welded joints can exceed 333 MPa, meeting the demand for lightweight, high-strength materials in shipbuilding structures. However, existing welding methods for this high-strength aluminum alloy for marine applications primarily focus on joining materials of the same type. The bottleneck for joining these materials to the 6xxx series (for example, mooring rails are typically made of 6082 (Al-Mg-Si) aluminum alloy) is the lack of a welding process that ensures both joint mechanical properties and welding efficiency. During welding, if process control is not rigorous, defects such as porosity, cracks, and slag inclusions can occur in the joints, severely restricting the expanded application of this material in shipbuilding structures. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for welding a high-strength marine aluminum alloy plate to an aluminum alloy mooring rail, so as to solve the deficiency of the prior art that there is no suitable and efficient welding process for high-strength marine aluminum alloy materials and 6xxx series aluminum alloy rails.

[0004] In order to achieve the above objectives, the technical solutions of the present invention are as follows.

[0005] The present invention provides a method for welding a high-strength aluminum alloy plate for ship and an aluminum alloy mooring rail, characterized in that it comprises the following steps: (1) processing a V-shaped groove on the high-strength aluminum alloy plate for ship; beveling the mooring rail and processing the V-shaped groove; (2) the welding position is flat butt welding, and the weld is double-sided welding; semi-automatic MIG welding is first performed on the front side, with a welding current of 70 to 90A and a welding voltage of 15 to 18V; and then automatic MIG welding is performed on the back side, with a welding current of 120 to 160A and a welding voltage of 19 to 21V.

[0006] Preferably, the marine high-strength aluminum alloy plate is Al-Mg-Er aluminum alloy with a thickness of 4 to 6 mm, wherein the Mg content is 5.5% to 6.5% and the Er content is 0.10% to 0.25%; the material of the aluminum alloy mooring rail is 6xxx series Al-Mg-Si aluminum alloy, and the edge thickness of its panel is 8 mm.

[0007] Preferably, the groove angle of the marine high-strength aluminum alloy plate is 30-40° on one side; the bevel angle of the mooring rail is 12-15°, the groove angle is 30-40° on one side, and the groove gap is 1-2 mm.

[0008] Preferably, the welding material used in the welding is a 1.2 mm diameter marine high-strength aluminum alloy matching welding wire, the chemical composition of which has a Mg content of 5.5% to 6.5% and an Er content of 0.10% to 0.25%.

[0009] Preferably, the welding speed of the semi-automatic MIG welding is 25-30 cm / min, and the shielding gas flow rate is 25-28 L / min; the welding speed of the automatic MIG welding is 35-38 cm / min, and the shielding gas flow rate is 20-25 L / min.

[0010] Preferably, the protective gas is argon.

[0011] The welding method of the present invention can produce welds with good surfaces, no pores, and no cracks, and can ensure that the tensile strength of the welded joint exceeds 175MPa. The welded joint surface remains intact after 180° bending. It also achieves efficient connection between marine high-strength aluminum alloy materials and 6xxx aluminum alloy mooring rails. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the welding groove between the marine high-strength aluminum alloy plate and the 6082 aluminum alloy mooring rail of the present invention;

[0013] The numbers in the accompanying drawings are as follows: 1- marine high-strength aluminum alloy plate, 2- 6082 aluminum alloy mooring rail, 3- weld. DETAILED DESCRIPTION

[0014] Those skilled in the art should recognize that the present embodiment is only used to illustrate the present invention, and is not intended to limit the present invention. Any changes or modifications to the embodiment within the scope of the present invention are within the scope of the claims of the present invention.

[0015] Example 1

[0016] (1) Welding materials

[0017] The material of marine high-strength aluminum alloy plate is Al-Mg-Er aluminum alloy, with a thickness of 4mm. The chemical composition contains 6.13% Mg and 0.19% Er.

[0018] The material of the tie-down track is 6082 aluminum alloy, and the panel edge thickness is 8mm;

[0019] The diameter of the welding wire is 1.2 mm, and the chemical composition includes Mg content of 5.96% and Er content of 0.18%.

[0020] The shielding gas used for welding is argon with a purity of ≥99.995%.

[0021] (2) Welding method

[0022] The groove angle of the marine high-strength aluminum alloy plate is 30° on one side, the bevel angle of the mooring track is 12°, and the groove angle is 35°, so that the thickness at the upper edge of the groove is equivalent to the thickness of the marine high-strength aluminum alloy plate, and the groove gap is 2mm.

[0023] Under the conditions of ambient temperature not less than 0℃ and relative humidity not higher than 85%, flat position double-sided welding is adopted: semi-automatic MIG welding is performed on the front side, with a welding current of 75A, a welding voltage of 16V, a welding speed of 26cm / min, and a gas flow rate of 25L / min; after the front side welding is completed, a milling cutter is used to clean the root and buckle the groove until there are no defects in the weld; then automatic MIG welding is performed on the back side, with a welding current of 130A, a welding voltage of 19V, a welding speed of 36cm / min, and a gas flow rate of 21L / min.

[0024] (3) Test results

[0025] From the appearance of the weld, it can be seen that the weld surface is well formed and has no obvious defects such as pores and cracks.

[0026] According to GB / T2651-2008, the tensile and bending properties of the welded joints were tested. The tensile strength of the welded joints was 182 MPa and the yield strength was 145 MPa.

[0027] Welded joints were tested for bending properties according to GB / T2653-2008. The bending core diameter was 24mm. After 180° bending, cracks or other defects on the specimen surface were no longer than 3mm.

[0028] Example 2

[0029] (1) Welding materials

[0030] The material of marine high-strength aluminum alloy plate is Al-Mg-Er aluminum alloy, with a thickness of 6mm. The chemical composition contains 6.27% Mg and 0.21% Er.

[0031] The material of the tie-down track is 6082 aluminum alloy, and the panel edge thickness is 8mm;

[0032] The diameter of the welding wire is 1.2 mm, and the chemical composition includes Mg content of 5.96% and Er content of 0.18%.

[0033] The shielding gas used for welding is argon with a purity of ≥99.995%.

[0034] (2) Welding method

[0035] The groove angle of the marine high-strength aluminum alloy plate is 40° on one side, the bevel angle of the mooring track is 15°, and the groove angle is 30°, so that the thickness at the upper edge of the groove is equivalent to the thickness of the marine high-strength aluminum alloy plate, and the groove gap is 2mm.

[0036] Double-sided welding in a flat position is adopted under the conditions of an ambient temperature of not less than 0℃ and a relative humidity of not higher than 85%: semi-automatic MIG welding is performed on the front side with a welding current of 85A, a welding voltage of 18V, a welding speed of 28cm / min, and a gas flow rate of 28L / min; after the front side welding is completed, a milling cutter is used to clean the root and groove until there are no defects in the weld; then automatic MIG welding is performed on the back side with a welding current of 150A, a welding voltage of 21V, a welding speed of 38cm / min, and a gas flow rate of 24L / min.

[0037] (3) Test results

[0038] From the appearance of the weld, it can be seen that the weld surface is well formed and has no obvious defects such as pores and cracks.

[0039] According to GB / T2651-2008, the tensile and bending properties of the welded joints were tested. The tensile strength of the welded joints was 184 MPa and the yield strength was 145 MPa.

[0040] Welded joints were tested for bending properties according to GB / T2653-2008. The bending core diameter was 36mm. After 180° bending, cracks or other defects on the specimen surface were no longer than 3mm.

Claims

1. A method for welding a marine high-strength aluminum alloy plate and an aluminum alloy mooring rail, characterized in that: The method comprises the following steps: (1) processing a V-shaped groove on a high-strength aluminum alloy plate for shipbuilding, with a groove angle of 30 to 40° on one side; beveling a mooring rail, with a beveling angle of 12 to 15°, and processing a V-shaped groove, with a groove angle of 30 to 40° on one side and a groove gap of 1 to 2 mm; (2) The welding position is flat butt welding, and the weld is double-sided welding; first perform semi-automatic MIG welding on the front side, with a welding current of 70-90A and a welding voltage of 15-18V; then perform automatic MIG welding on the back side, with a welding current of 120-160A and a welding voltage of 19-21V; The ship-grade high-strength aluminum alloy plate is an Al-Mg-Er aluminum alloy with a thickness of 4 to 6 mm, wherein the Mg content is 5.5% to 6.5% and the Er content is 0.10% to 0.25%; the material of the aluminum alloy mooring rail is a 6xxx series Al-Mg-Si aluminum alloy, and the edge thickness of its panel is 8 mm; the welding material used for the welding is a ship-grade high-strength aluminum alloy matching welding wire with a diameter of 1.2 mm, and the chemical composition has an Mg content of 5.5% to 6.5% and an Er content of 0.10% to 0.25%.

2. The welding method according to claim 1, characterized in that The welding speed of the semi-automatic MIG welding is 25-30 cm / min, and the shielding gas flow rate is 25-28 L / min; the welding speed of the automatic MIG welding is 35-38 cm / min, and the shielding gas flow rate is 20-25 L / min.

3. The welding method according to claim 2, characterized in that The protective gas is argon.

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