Friction stir welding of titanium alloys OT-4 and VT-20

Abstract

The products made with titanium alloys are widely used in aircraft building, rocket engineering and shipbuilding. In the assembly of these products in these industries fusion welding is used, but its labour intensive and costly process. Reduction of the labour intensity and cost value of joining titanium alloys is possible by using a friction stir welding (FSW) method. In article, FSW distribution in Russia is considered and provides research of weldability of OT-4 (Ti-4Al-1.5Mn analogue) and VT-20 (Ti-6.5Al-1Mo-1V-2Zr analogue) titanium alloys by FSW. The aim of the research is obtaining sound welds of these alloys, designing of a FSW tool, gathering information of a welding process and compiling a list of recommendations for welding. A series of experiments was carried out; the aim of the research for OT-4 was incompletely achieved and for VT-20 was completely achieved. A tool for FSW was developed, data of welding forces and temperatures at different modes are given.