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A method for improving the welding strength of 7-series aluminum alloy profiles with a wall thickness of 2 mm or less

A technology for aluminum alloy profiles and welding strength, applied in the field of aluminum alloy materials, can solve the problems of reduced welding strength, hot cracks at weld positions, and large local temperature rise, so as to avoid local overheating, improve welding strength, and avoid hot cracks.

Active Publication Date: 2021-05-07
福建祥鑫股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for 7-series aluminum alloy profiles whose thickness is less than 2 mm, the existing welding methods cannot perfectly take advantage of the high strength of the existing 7-series alloys
As far as the current friction stir welding process is concerned, the main reason is that the reduction of the profile wall thickness leads to the rapid accumulation of heat during welding, and the local temperature rise is too large, resulting in the burning of Zn and Mg alloy elements in the alloy, resulting in a decrease in welding strength. It will also cause defects such as thermal cracks and pores at the position of the weld, and excessive heat concentration will lead to an increase in grain coarsening in the heat-affected zone near the weld

Method used

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  • A method for improving the welding strength of 7-series aluminum alloy profiles with a wall thickness of 2 mm or less
  • A method for improving the welding strength of 7-series aluminum alloy profiles with a wall thickness of 2 mm or less

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Embodiment 1

[0027] A method for improving the welding strength of 7-series aluminum alloy profiles with a wall thickness of 2 mm or less,

[0028] It is characterized in that the method comprises:

[0029] (1) Alloy smelting: The mass percentage of the alloy composition is as follows: Si: 0.5%, Cu: 0.2%, Zn: 5.7%, Mg: 1.7%, Zr: 0.1%, Fe: 0.3%, Ti: 0.25%, Mn: 0.6%, other elements ≤ 0.05%, the sum of other elements ≤ 0.15%, the balance is Al; alloy melting temperature is 740°C;

[0030] (2) Homogenization of ingots: Homogenize the ingots obtained in step 1. The homogenization temperature is 455°C, keep warm for 4.5h, then rise to 515°C, keep warm for 25h, and then come out of the furnace and air-cool; (3) profiles Extrusion: heat the ingot obtained in step 2 to 490°C, the temperature of the extrusion cylinder is 450°C, and the profile speed is 4.5m / min;

[0031] (4) Profile heat treatment: The profile extruded in step 3 is subjected to online quenching treatment, and then aging treatment ...

Embodiment 2

[0034] A method for improving the welding strength of 7-series aluminum alloy profiles with a wall thickness of 2 mm or less, the method comprising:

[0035] (1) Alloy smelting: The mass percentage of the alloy composition is as follows: Si: 0.5%, Cu: 0.2%, Zn: 5.7%, Mg: 1.7%, Zr: 0.1%, Fe: 0.3%, Ti: 0.25%, Mn: 0.6%, other elements ≤ 0.05%, the sum of other elements ≤ 0.15%, the balance is Al; alloy melting temperature is 730°C;

[0036] (2) Homogenization of ingots: Homogenize the ingots obtained in step 1. The homogenization temperature is 460°C, keep warm for 4 hours, then rise to 520°C, keep warm for 24 hours, and then take out the furnace and air cool; (3) Profile extrusion Compression: heat the ingot obtained in step 2 to 495°C, extrude cylinder temperature to 440°C, and profile speed to 6m / min;

[0037] (4) Profile heat treatment: The profile extruded in step 3 is subjected to online quenching treatment, and then aging treatment is performed after the online quenching ...

Embodiment 3

[0040] A method for improving the welding strength of 7-series aluminum alloy profiles with a wall thickness of 2 mm or less, the method comprising:

[0041] (1) Alloy smelting: The mass percentage of the alloy composition is as follows: Si: 0.5%, Cu: 0.2%, Zn: 5.7%, Mg: 1.7%, Zr: 0.1%, Fe: 0.3%, Ti: 0.25%, Mn: 0.6%, other elements ≤ 0.05%, the sum of other elements ≤ 0.15%, the balance is Al; alloy melting temperature is 750°C;

[0042](2) Homogenization of ingots: Homogenize the ingots obtained in step 1. The homogenization temperature is 450°C, keep warm for 5h, then rise to 510°C, keep warm for 26h, and then come out of the furnace for air cooling; (3) Profile extrusion Compression: heat the ingot obtained in step 2 to 480°C, extrude cylinder temperature to 460°C, and profile speed to 3m / min;

[0043] (4) Profile heat treatment: The profile extruded in step 3 is subjected to online quenching treatment, and then aging treatment is performed after the online quenching treat...

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Abstract

The invention discloses a method for improving the welding strength of 7-series aluminum alloy profiles with a wall thickness of less than 2mm, which comprises the steps of alloy smelting, ingot homogenization, profile extrusion, profile heat treatment, friction stir welding and the like. Through the method of the present invention, the strength of the 7 series alloy after welding can be greater than 85% of the base metal; the present invention increases the content of Zn, Mg, Ti, and Mn within a reasonable range, so that the Zn in the welding process , the burning loss of Mg is reduced, and the effect of Ti and Mn can refine the crystal phase, causing defects such as hot cracks and pores at the weld position. After welding, the profile continues to undergo aging treatment, which can avoid local overheating after welding. The method makes the cooling slow, avoids thermal cracks, and can further refine the grains and improve the welding strength.

Description

technical field [0001] The invention belongs to the field of aluminum alloy materials, and in particular relates to a method for improving the welding strength of 7-series aluminum alloy profiles with a wall thickness of less than 2 mm. Background technique [0002] Different from traditional cars, new energy vehicles use batteries as power to drive the car. Due to the constraints of the weight of the power battery and the mileage of the power battery, in terms of vehicle design and material application, the lightweight of the car body has become the first consideration for car companies question. [0003] The high-strength properties of the 7-series aluminum alloy make it possible to apply it in new energy vehicles. However, in order to achieve the ultimate goal of weight reduction, the thickness of most profiles is less than 2mm, and the profile cannot be assembled into a finished product. Avoid welding between profiles. However, for the 7-series aluminum alloy profiles ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23P15/00B23K20/12
CPCB23K20/122B23K20/125B23P15/00
Inventor 黄铁兴黄祯荣冯永平池海涛戴应鑫
Owner 福建祥鑫股份有限公司