Welding method capable of eliminating hook defects of magnesium alloy friction stirring overlap joint

A technology for hook-shaped defects and lap joints, applied in welding equipment, non-electric welding equipment, metal processing equipment, etc., can solve problems such as difficulty in ensuring joint quality, achieve simple process assembly and welding processes, broad industrial application prospects, and improve The effect of joint performance

Active Publication Date: 2015-06-03
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] In order to solve the problems in the prior art that hook-shaped defects are easily produced during the friction stir lap welding process of magnesium alloys and the joint quality is difficult to guarantee, the present invention provides a friction stir welding method for eliminating the hook-shaped defects of magnesium alloy friction stir lap joints

Method used

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  • Welding method capable of eliminating hook defects of magnesium alloy friction stirring overlap joint
  • Welding method capable of eliminating hook defects of magnesium alloy friction stirring overlap joint
  • Welding method capable of eliminating hook defects of magnesium alloy friction stirring overlap joint

Examples

Experimental program
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Effect test

Embodiment 1

[0030] The 2.4mm thick magnesium alloy plate is lapped and assembled, a 0.1mm thick tin interlayer is preset between the upper and lower plates, and then conventional friction stir spot welding (needle diameter 3mm, shaft shoulder 10mm, needle length 1.8mm, speed 3000r / min, dwell time 5s). Microstructural analysis and mechanical performance tests showed that there were no hook defects in the joints (such as figure 2 As shown), it is replaced by the Sn-Mg alloy zone formed by the interaction of tin and magnesium alloy, and the tensile load of the spot welded joint is about 3.0kN.

Embodiment 2

[0032] The 2.4mm thick magnesium alloy plate is lapped and assembled, and a 0.2mm thick zinc interlayer is preset between the upper and lower plates for conventional friction stir spot welding (needle diameter 3mm, shaft shoulder 10mm, needle length 1.8mm, speed 3000r / min , dwell time 5s). Microstructural analysis revealed no hook defects in the joint (eg image 3shown), replaced by the Zn-Mg alloy zone formed by the diffusion reaction of zinc and magnesium alloy. The mechanical performance test shows that the tensile load of the spot welded joint is about 4.0kN.

Embodiment 3

[0034] The 2.4mm thick magnesium alloy plates are lapped and assembled, and a 0.1mm thick zinc-tin alloy (5wt% zinc content, the rest is tin) interlayer is coated between the upper and lower plates, and conventional friction stir spot welding (needle diameter 3mm, Shaft shoulder 10mm, needle length 1.8mm, speed 3000r / min, dwell time 5s). Microstructural analysis revealed no hook defects in the joint (eg Figure 4 shown), replaced by the Zn-Sn-Mg ternary alloy region formed by the diffusion reaction of zinc-tin alloy and magnesium alloy. The mechanical performance test shows that the tensile load of the spot welded joint is about 3.4kN.

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Abstract

The invention provides a welding method capable of eliminating hook defects of a magnesium alloy friction stirring overlap joint (including spot welding and wire welding) and belongs to the technical field of magnesium alloy welding. The welding method has the advantages that a low-melting-point metal or alloy interlayer is prearranged between an upper magnesium alloy plate and a lower magnesium alloy plate which are to be welded, pressure and heat generated from shaft shoulder friction are adopted to enable the interlayer and magnesium alloy to react, and a novel combination area is generated in a joint heat affected zone and a thermo-mechanically affected zone, so that formation of the hook defects is avoided, and mechanical properties of the welded joint is improved.

Description

technical field [0001] The invention relates to the field of magnesium alloy welding, in particular to a method for eliminating hook-shaped defects of magnesium alloy friction stir lap joints (spot welding or wire welding). Background technique [0002] Magnesium alloy has a series of advantages such as low density, high specific strength, good damping and shock absorption, easy machining and good recyclability, so it has extremely important application value and broad application prospects in aerospace, automotive and other industries. [0003] However, due to the poor plastic deformation ability of magnesium, most of the current magnesium alloy products are castings. In recent years, with the rapid development of automobiles, high-speed trains, large aircraft, aerospace vehicles, weapons and other equipment manufacturing industries, wrought magnesium alloys have developed rapidly, and the importance of achieving reliable connections has become increasingly prominent. Alth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K20/12B23K20/233
CPCB23K20/1225B23K20/16B23K20/2333
Inventor 倪丁瑞徐荣正马宗义
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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