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A friction stir welding stirring head with improved penetration depth

A technology of friction stirring and penetration depth, which is applied in welding equipment, non-electric welding equipment, metal processing equipment, etc., can solve the problems of large number of stirring heads, lower production efficiency, weak connection and incomplete penetration of roots, etc., and achieve improved design Threshold, improve adaptability, reduce cost effect

Active Publication Date: 2022-08-09
SICHUAN AEROSPACE LONG MARCH EQUIP MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, based on the overall consideration of penetration and preventing interference with the backing plate, the design with the length of the stirring needle 0.1-0.3mm smaller than the thickness of the workpiece to be welded is generally adopted at present, that is, only the workpiece that is 0.3mm longer than the stirring needle can be stably welded. Thickness; In actual production, the stirring head corresponding to the length of the stirring needle is selected according to the theoretical thickness of the welding workpiece before welding, and the welding process will not be replaced, but the welding of the workpiece caused by the deformation of the welding tool, welding deformation, especially the error of machining accuracy Influenced by engineering factors such as thickness fluctuations (for large-scale welded structures such as rocket fuel storage tanks, rail train bodies, and ships, a weld is several meters to more than ten meters or even longer, affected by processing accuracy, different parts of the entire weld And there are different degrees of fluctuations in the welding thickness of the weld seam of the same part in different batches, generally 0.1-0.5mm, such situations are inevitable in actual production), the size fluctuation makes the thickness of the workpiece exceed the maximum thickness that can be welded by the stirring head, and it is easy to Defects such as weak connection and incomplete penetration of the root caused by the back weld
The size of such defects is generally small, and it is difficult or even impossible to be detected by existing non-destructive testing methods such as X-rays and ultrasound, which will cause great hidden dangers to joint performance and seriously reduce the bearing capacity and fatigue performance of the joint. Welds are more likely to have defects such as weak connections and incomplete penetration, and the hidden dangers of joint performance increase significantly
[0004] At present, in order to prevent defects such as weak connection and incomplete penetration of the root, in the actual production, measures such as increasing the pressure of the shaft shoulder and multi-pass welding are used to control the welding process, but the process control threshold is small and cannot be solved fundamentally Defects such as weak connection and incomplete penetration of the root; or mechanical grinding and machining methods are used to remove a certain thickness of weld root material after welding, which increases production costs and reduces production efficiency
[0005] In addition, there are often a large number of welding structures with a difference of only 1mm in the welding thickness on the same product. In order to solve the adaptability of the stirring head to the welding thickness and prevent defects such as weak connections and incomplete penetration of the root, in current actual production, the stirring needle One stirring head is prepared at intervals of 0.2 mm in length, resulting in a large number of stirring heads, high cost, and cumbersome management

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  • A friction stir welding stirring head with improved penetration depth
  • A friction stir welding stirring head with improved penetration depth
  • A friction stir welding stirring head with improved penetration depth

Examples

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Effect test

Embodiment 1

[0037] A friction stir welding stirring head with improved penetration depth, for 2219T87 aluminum alloy with a welding thickness δ of 8.5mm, the stirring needle is a threaded structure with three cross-sectional planes, and the three cross-sectional planes are evenly spaced at 120°. The end position M of the root thread is included within 0.5mm of any section plane on the side of the stirring needle and the edge of the forward side along the rotation direction of the stirring head, the angle α of the section plane is 86°, the taper of the stirring needle γ is 12°, and the length of the stirring needle L is 7.8mm , according to formula (1), the diameter d of the end of the stirring needle is calculated to be 7.4 mm, and the plane of the end of the stirring needle is processed to form a circular arc spiral groove structure with an interval of 120° uniformly distributed. The spiral cylindrical coordinate equation of the circular arc spiral groove is: Formula (2), where a=30, b=10...

Embodiment 2

[0040] A friction stir welding stirring head with improved penetration depth. The only difference between the stirring head and Example 1 is that the plane of the end of the stirring needle is machined with a circular arc straight groove structure with an even distribution of 120°, and the groove width is 2 mm, Depth 1mm. The above-mentioned stirring head is used under the combination of conventional process parameters of rotating speed W of 600r / min, welding speed V of 200mm / min, pressing amount h of 0.2mm, and inclination angle β of 2.5°, the stable welding penetration δ is 8.5mm and the thickness is 2219T87 aluminum. alloy, the penetration effect is comparable to that of Example 1.

Embodiment 3

[0042] A friction stir welding stirring head with improved penetration depth, for 2219T87 aluminum alloy with a welding thickness δ of 15 mm, the stirring head differs from Example 1 only in that the length L of the stirring needle is 14.4 mm, and the stirring is calculated according to formula (1). The diameter d of the needle end is 11mm, the helical cylindrical coordinate equation (2) of the circular arc spiral groove at the end is a=25, b=56, the width of the groove is 2.5mm, the depth is 1.5mm, and the distance between the plane sections on the side of the stirring needle is The included angle α is 80°, and the shoulder diameter D is 30mm. The above-mentioned stirring head is used for welding at a combination of conventional process parameters with a rotating speed W of 400 r / min, a welding speed V of 150 mm / min, a downward pressure h of 0.4 mm, and an inclination angle β of 2.5°. In the same way, no defects such as weak connection and incomplete penetration were observed...

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Abstract

The invention discloses a friction stir welding stirring head with improved penetration depth, which comprises a stirring needle, a shaft shoulder and a clamping part which are connected in sequence. And the end position of the root thread is included in the edge of any cross-sectional plane on the side of the stirring needle along the direction of rotation of the stirring head, and three arc spiral grooves or arc straight grooves are evenly distributed on the end plane of the stirring needle. The invention increases the friction area between the end of the stirring needle and the welding seam metal, enhances the stirring ability of the root welding seam material, increases the temperature of the root welding seam metal, promotes the plasticization and flow of the root welding seam material, improves the depth of welding, and improves the resistance to the welding seam. The adaptability of welding thickness fluctuation can effectively prevent the weak connection at the root of the weld and incomplete penetration defects.

Description

technical field [0001] The invention belongs to the technical field of friction stir welding, and relates to a friction stir welding stirring head with improved penetration depth. Background technique [0002] Friction stir welding uses a specially designed stirring head to rotate and insert the workpiece to be welded. Under the action of frictional heat, plastic deformation heat generation and axial mechanical pressure, the material to be welded is locally plasticized and flowed, and a dense connection is formed through recrystallization. The joint is a high-quality, efficient and green solid-phase connection technology. This technology has been widely used in aerospace, rail transit, shipbuilding, power electronics and new energy vehicles and other industries. [0003] In conventional friction stir welding, in order to ensure the penetration of the workpiece, the length of the stirring needle is required to be as close as possible to the welding thickness of the workpiece...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K20/12
CPCB23K20/1255
Inventor 郑森木裴利程朱志陈勇卢启强沈勇
Owner SICHUAN AEROSPACE LONG MARCH EQUIP MFG CO LTD