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A kind of preparation method of high-strength aluminum alloy welded joint

A welding joint and welding method technology, applied in the field of high-strength aluminum alloy processing, can solve the problems of strength loss of welded joints, high sensitivity to thermal cracks, and difficulty in meeting high strength, and achieve good weld formation, high strength and joint coefficient. , the effect of no obvious defects

Active Publication Date: 2016-08-24
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with riveting and bolting, welding has the advantages of saving materials, reducing dead weight, good sealing performance, and high production efficiency. The equilibrium partition coefficient k in 0 <1, when the molten weld pool crystallizes, it segregates at the grain boundary to form a composite precipitate phase containing Cu. The eutectic temperature of this phase is relatively low, and the crystallization temperature range is relatively large. Under the action of tensile stress, it is very easy to produce welding hot cracks. At the same time, the strength loss of welded joints is serious, and it is difficult to apply to welded structures. For a long time, this type of alloy has been considered as a non-weldable material
Cu is the main element that leads to high sensitivity to welding hot cracks in this type of alloy, but Cu element in this type of alloy can increase the dispersion of precipitated phases, and it has solid solution strengthening effect. In addition, Cu atoms dissolve into the precipitated phase η′ and In the η phase, the potential difference between the grain and the grain boundary is reduced, and the tendency of intergranular cracking is suppressed, thereby improving the corrosion resistance of the alloy. Therefore, although the Al-Zn-Mg alloy without Cu has good welding performance, it is difficult to Meet the requirements of high strength and good corrosion resistance

Method used

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  • A kind of preparation method of high-strength aluminum alloy welded joint
  • A kind of preparation method of high-strength aluminum alloy welded joint
  • A kind of preparation method of high-strength aluminum alloy welded joint

Examples

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Comparison scheme
Effect test

Embodiment 1

[0020] Example 1: Fully automatic TIG wire-filled welding of 2 mm thick Al-7.83Zn-2.87Mg-0.67Cu-0.50Mn-0.23Zr-0.14Er hot-rolled and T6 state plates.

[0021] (1) Cut the plate into a size of about 105mm×100mm, and carry out chemical cleaning (70°C 8-10% NaOH solution → rinse with water → 30-40% HNO 3 solution → rinse with water → air dry), use a stainless steel wire brush to polish the butt joints of the plates before welding.

[0022] (2) The welding adopts a fully automatic TIG welding machine, the welding direction is perpendicular to the rolling direction of the base metal, the current type is sine wave AC, the diameter of the welding wire is 1.6mm, the diameter of the tungsten pole is 3mm, the distance between the tungsten pole and the base metal is 3mm, and the welding current is 125A , The welding speed is 27cm / min, the wire feeding speed is 40cm / min, the shielding gas is Ar, and the front and back gas flow rates are 20L / min and 10L / min respectively. Macro inspection a...

Embodiment 2

[0024] Embodiment 2: The metallographic structure analysis and mechanical performance test of the welded joint obtained in Example 1 were carried out.

[0025] (1) For the welded joint of the T6 state base metal, the metallographic sample is taken perpendicular to the weld, and after mechanical grinding and polishing, the Keller reagent (1mlHF+1.5mlHCL+2.5mlHNO 3 +95mlH 2 O) and electrochemical corrosion method (electrolyte is 40mlH 3 PO 4 +38mlC 2 h 5 OH+20mlH 2 O) corrode the joint, and then observe the metallographic structure of each area of ​​the joint under the OLYMPUS-BX51M metallographic microscope, figure 1 It is the metallographic structure of the weld area, and its shape is a small equiaxed dendrite with a grain size of about 40 μm. figure 2 , 3 They are the grain morphology of the heat-affected zone and the base metal, respectively, both of which are elongated by rolling and partially recrystallized. The grain size is uneven, but there is no obvious grain g...

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Abstract

The invention discloses a manufacturing method of a high-strength aluminum alloy welding connector, and belongs to the technical field of high-strength aluminum alloy machining. The manufacturing method adopts Al-7.83Zn-2.87Mg-0.67Cu-0.50Mn-0.23Zr-0.14Er base metal and an Al-4.70Mg-0.70Mn-0.10Zr-0.30Er welding wire, after full-automatic TIG filler rod welding and proper post-welding heat processing, a nanoscale secondary precipitated phase formed by micro alloy elements Er and Zr serves as an effective nucleation core in a molten pool, the welding joint grain is fined, dislocation and sub-grain boundaries are pinned in a heat affected area, re-crystallization of the heat affected area is effectively inhibited, and softening of the heat affected area is reduced. The manufactured welding connector has the advantages that tensile strength is high, welding joints are well formed, and no obvious defect exists, and has the potential for industrial application.

Description

technical field [0001] The invention belongs to the technical field of high-strength aluminum alloy processing, and relates to the welding of Al-Zn-Mg-Cu type alloys (named as 7XXX series aluminum alloys in China's national standard), more specifically, to an Al-Zn-Mg-Cu- Welded joint preparation of Mn-Zr-Er deformed aluminum alloy sheets. Background technique [0002] The literature survey results show that in aerospace, transportation and other fields, with the development trend of lightweight and high performance, high-strength aluminum alloys have become important structural materials in these fields, the most representative of which is Al-Zn-Mg -Cu type alloy, its yield strength is basically above 500MPa, which is the highest strength type in the aluminum alloy system. A large number of alloy plates and pipes of this type need to be connected before use, and the connection technology is currently mainly riveted and bolted. Compared with riveting and bolting, welding h...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23P15/00B23K9/167
CPCB23K9/164B23K9/167B23K2101/185B23K2103/10C21D9/50
Inventor 李晓延张亮聂祚仁黄晖孙建通王月琦曾宪龙
Owner BEIJING UNIV OF TECH