RU2780760C1 - Method for fabrication by friction stir welding of structures from sheets of aluminum or copper alloys - Google Patents

Abstract

FIELD: welding production.

SUBSTANCE: invention relates to the field of welding production. The method can be used to fabricate structures from aluminum or copper alloys by friction stir welding, in particular for the manufacture of fuel tanks for launch vehicles. On a tool for friction stir welding, a milling nozzle with cutting plates fixed to it is preliminarily fixed. The parts are connected by welding with simultaneous cleaning of the surface of the parts in the area of ​​the weld by means of a rotating milling nozzle while deepening said tool for welding. The fixation height of the nozzle relative to the shoulder of the tool for welding is preliminarily determined from the condition of obtaining a stripping zone, the depth and width of which ensures the absence of defects and traces from the welding tool on the surface of the parts.

EFFECT: use of the proposed method allows to reduce the time for manufacturing a welded product from an aluminum alloy obtained by friction stir welding.

1 cl, 4 dwg, 1 ex

Description

The invention relates to the field of welding production, in particular to a method of friction stir welding of aluminum and copper alloys.

A known method of friction stir welding [RU No. 2357843 dated July 25, 2007], including the assembly of the elements to be welded and subsequent welding by rotating the welding tool with a replaceable finger, while the rotation of the tool is carried out in the direction opposite to the deviation angle of the grooves made on the replaceable finger, due to which ensures the movement of the plasticized metal from top to bottom to create additional pressing pressure of the metal in the weld zone.

A known method of friction stir welding [RU No. 2714008 of March 19, 2019] of aluminum structures made of sheet parts, including their installation and fixing, followed by welding, while the parts to be welded are fixed on a rigid substrate made of a plate made of a material with a lower thermal conductivity, than the materials to be welded.

A significant disadvantage of these methods is that after welding, a “burr” defect appears (Fig. 1). This defect must be removed by subsequent stripping. In addition, during the welding process, due to the contact of the rotating shoulder with the surface of the parts to be welded, a surface with a low roughness value is formed, which has irregularities characteristic of friction stir welding (Fig. 1, Fig. 2). Traces after the passage of the welding tool are not a significant defect, however, on critical structures of the aircraft and rocket industry, they must be removed by subsequent cleaning by grinding or milling.

The technical result of the invention is the creation of a friction stir welding method that provides simultaneous milling cleaning together with welding to remove the above defects, which will make it possible to combine the welding and cleaning operations into one, and significantly reduce the time for manufacturing welded products.

The technical result is achieved by the fact that in the proposed method of friction stir welding, which includes the installation of parts on the substrate and their fixing, first install the milling nozzle, on which the cutting plates are fixed, on the tool for welding, having previously determined the required installation height relative to the shoulder of the tool, and then produce welding with simultaneous milling cleaning.

On FIG. 1 shows the appearance of the weld without stripping. The defect "burr" and a trace from the welding tool are shown.

On FIG. 2 shows a section of welded products in the plane of their joint, which shows the relief of the trace from the welding tool.

On FIG. 3 shows a diagram of a friction stir welding process using a milling nozzle.

On FIG. 4 shows a view of the welded product obtained using the proposed method.

An example of the implementation of the invention.

In FIG. 3 shows a diagram of a welding method using a milling head. Sheets 7.6 mm thick made of AMG6 alloy were used as welded parts. Two plates 1 measuring 300x50 mm were mounted on a rigid substrate of a friction stir welding machine and fixed with tacks from above. Before welding, flats were made on the welding tool 2 for fixing the milling nozzle 3, on which the cutting inserts for processing aluminum alloys 4 were installed. a stripping zone 5 with a width of 30 mm was formed on the milling head. When determining the height of the nozzle 3 relative to the shoulder, the selected inclination of the tool for welding 1 - 2° was taken into account. After installing the milling nozzle 2 on the tool for welding 1 and fixing the tool with the nozzle in the machine spindle, the rotation of the tool was turned on with a given rotational speed n, rpm. Next, the tool 1 plunged into the joint 6 between the plates 1 to the working depth. After immersion, the rotating tool 2 moved along the junction of the parts to be welded 6, while the milling nozzle 3 installed on the tool rotated together with the tool 2, and the cutting inserts 4 carried out simultaneous milling cleaning immediately after the tool 2, forming the cleaning zone 5. After welding, the movement the tool has been stopped, the tool has been lifted out of the metal, and rotation has been turned off. From the resulting welded plate, sections of the beginning and end of the seam were cut off. A part manufactured using the proposed method is shown in Fig. four.

To compare the performance of the proposed method, an experiment similar to the one described above was carried out, but without the use of a milling nozzle. After welding, a “burr” defect and traces of movement of the welding tool formed on the surface of the parts to be welded. Then, for milling cleaning, the welding tool was replaced with a milling cutter in the machine spindle. Next was milling. After milling, the cutter was replaced with a welding tool for the manufacture of the following products. Thus, the time for two machine changeovers, two tool changes and cutting time was added to the technological process of manufacturing welded products, which led to a significant decrease in productivity.

The use of the proposed method has significantly reduced the time for manufacturing a welded product from an aluminum alloy obtained by friction stir welding. The proposed method can be used to manufacture various structures for the aircraft and rocket industry, in particular for the manufacture of fuel tanks for launch vehicles.

Claims (1)

A method for manufacturing structures from sheets of aluminum or copper alloys by friction stir welding, including fixing the parts to be welded and their connection by welding, characterized in that a milling nozzle with cutting plates fixed to it is preliminarily fixed on the tool for friction stir welding, and the connection is made by welding with simultaneous cleaning of the surface of the parts in the weld zone by means of a rotating milling nozzle when deepening the said tool for welding, while preliminarily determining the fixation height of the nozzle relative to the shoulder of the welding tool from the condition of obtaining a cleaning zone, the depth and width of which ensures the absence of defects and traces of welding tool.

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