Friction stir welding process for enhancing mechanical property of joint

A friction stir and welding technology, applied in welding equipment, manufacturing tools, non-electric welding equipment, etc., can solve the problems of difficult rapid heat transfer in the welding nugget area, obvious softening effect of HAZ annealing, etc., achieve broad industrial application prospects, reduce temperature , to avoid the effect of oxidation

Active Publication Date: 2012-07-04
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

[0004] The purpose of the present invention is to provide a friction stir welding process that enhances the mechanical properties of the joint, and solves the problems in the prior art that the heat generated in the nugget area is difficult to transmit quickly, and the annealing and softening effect of the HAZ is obvious.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Use a 3 mm thick T1 cold-rolled (H) pure copper sheet with a yield strength of 330 MPa. Carry out welding with the stirring head of shaft shoulder diameter 14 millimeters, in the welding process with high pressure (in this embodiment, pressure is about 0.5MPa) flowing cooling water rapidly cools weld seam, and the rotating speed of welding tool is respectively 400 and 800 rev / min , Under the welding parameters of the traveling speed of 50 mm / min, a defect-free welded joint is obtained. Tensile tests at room temperature show that the yield strength of the joint is 320 MPa at 400 rpm, which is close to the strength of the base metal; at 800 rpm, the yield strength of the joint drops to 280 MPa.

[0017] In this embodiment, a high-pressure nozzle device is used to spray a high-pressure flowing cooling medium. The high-pressure nozzle device is fixed on the machine base on which the stirring head is installed, and moves together with the stirring head. .

Embodiment 2

[0021] Use a 3 mm thick T1 cold-rolled (H) pure copper sheet with a yield strength of 330 MPa. Use a stirring head with a shoulder diameter of 14 mm for welding. During the welding process, a mixture of liquid nitrogen and alcohol flows under high pressure (in this embodiment, the pressure is about 0.5 MPa) (in this embodiment, the temperature of the cooling medium is about -50 ° C. ) rapid cooling of the weld seam, under the welding parameters of the welding tool rotating speed of 600 rpm and the travel speed of 50 mm / min, a defect-free welded joint is obtained. There is no obvious heat-affected zone in the joint, the tensile properties are equal to those of the base metal, and the grains in the weld nugget area are obviously refined (the grain size is about 500 nanometers).

[0022] In this embodiment, a high-pressure nozzle device is used to spray a high-pressure flowing cooling medium. The high-pressure nozzle device is fixed on the machine base on which the stirring head ...

Embodiment 3

[0026] Use 3 mm thick 6061-T651 and 7075-T651 rolled plates with strengths of 310 MPa and 575 MPa respectively, weld with a stirring head with a shoulder diameter of 10 mm, and use high pressure (in this embodiment, the pressure is 0.5 MPa) Left and right) a mixture of flowing liquid nitrogen and alcohol (in this embodiment, the temperature of the cooling medium is about -50°C) to rapidly cool the weld seam, under the welding parameters of the welding tool rotating speed of 600 rpm and the traveling speed of 200 mm / min, Obtain defect-free welded joints. The joint strengths are 300MPa and 550MPa respectively, which are close to the base metal strength.

[0027] In this embodiment, a high-pressure nozzle device is used to spray a high-pressure flowing cooling medium. The high-pressure nozzle device is fixed on the machine base on which the stirring head is installed, and moves together with the stirring head. .

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Abstract

The invention relates to the field of metal material welding, and particularly provides a friction stir welding process for enhancing the mechanical property of a joint. The friction stir welding process is applicable to welding for metal materials such as aluminum alloys, magnesium alloys, copper alloys, steel and the like, and solves the problems that heat generated in a weld nugget is difficult in rapid transmission, annealing and softening functions of an HAZ (heat affected zone) are obvious, and the like. A stirring head with a small-size shaft shoulder is used for welding with low heat input friction stir welding parameters, welding lines are rapidly cooled by high-pressure flow cooling media during welding, and the friction stir welding joint with an excellent performance is obtained. The friction stir welding process can be used for obviously enhancing the mechanical property of the welding joint, and is particularly applicable to welding for precipitation strengthened, machined and hardened on-ferrous metal materials and steel materials.

Description

Technical field: [0001] The invention relates to the field of metal material welding, and in particular provides a friction stir welding process for enhancing the mechanical properties of joints, which is suitable for welding metal materials such as aluminum alloys, magnesium alloys, copper alloys, and steel. Background technique: [0002] Friction stir welding (FSW) is a solid phase welding process invented by the British Welding Institute in 1991. Because FSW has the advantages of high energy utilization rate, environmental friendliness, less welding defects, and small weld residual stress, its joint performance is greatly improved compared with fusion welding, and it has received extensive attention since its invention. field has been increasingly widely used. However, although FSW greatly reduces the welding heat input, for FSW joints, especially for heat treatment-strengthened alloys or work-hardened alloys, after FSW, due to the obvious softening of the heat-affected ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K20/12B23K20/26
Inventor 薛鹏马宗义肖伯律
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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