Arconic SMZ, Moscow, Russia

A. M. Drits, Executive Officer of Business Development and New Technologies, e-mail: Alexander.Drits@arconic.com

Moscow Polytechnic University, Moscow, Russia

V. V. Ovchinnikov, Professor of a Chair “Materials Science”

Cheboksary Enterprise “Sespel”, Cheboksary, Russia

V. A. Bakshaev, Executive Officer

We defined the optimum parameters of friction stir welding, widely used in welded structure manufacturing using various aluminium alloys with 3.0–8.0 mm thickness. Friction stir welding of aluminium sheets obtains high-quality seams by the right choice of the tool depth in welded metal, the tool rotation frequency and its linear displacement speed along the joint or welding speed. The length of tool’s linear displacement along the joint for its one turn may be used as a friction stir welding parameter, defining the heat input in seam formation zone. Optimal rational range is defined, showing the tool’s linear displacement length along the joint for its one turn, and providing the high-quality formation of seams of Al – Mg alloys and other aluminium alloys. Conditions of plastic deformation of metal in permanent connection formation zone are defined by its heating temperature and deformation velocity, depending on the tool rotating frequency and velocity of its linear displacement along the joint. Our experimental investigation proved the qualitative formation of seams with friction stir welding of aluminium alloys at various values of these parameters. According to our calculations, high temperature at friction stir welding is reached with the contact of aluminium alloy with tool’s rotating shoulder. Temperature of aluminium alloy 1565ch in the area of contact with tool’s rotating shoulder may reach 620–648 ^oC: formation of thin metal layer in solid-liquid state is possible in the zone of contact of working tool’s shoulder with surface of welded billets. Aluminium alloy 1565ch is successfully welded with rather high speeds of welding. Optimal ratio Vweld/N for the alloy 1565ch is in the range of 0.04–0.38 mm/turn. Welding speed can be changed in the range of 4–18 m/hour and 8–34 m/hour with tool rotating speeds 1200 turn/min and 2000 turn/min, respectively. Welding speed should be decreased at friction stir welding for obtaining of qualitative compounds on denser aluminium alloys, containing rather large quantity of alloying and modifying elements. Using the tool with low diameter of plastified metal volume shoulder for friction stir welding could be insufficient for complete filling of the area retrievable behind the tool, leading to incomplete fusion in seams.

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