Effect of Electron-Beam Welding Speed on Weld Metal Mechanical Properties of 5V Titanium Alloy
The results of metallographic studies of 5V titanium alloy welds obtained with the range of electron-beam welding speeds from 20 to 120 m/h are presented. It was established that at all welding speeds some identical microstructure of a weld metal is formed, which can differ only in sizes and shapes of the primary crystals. The results of Vickers hardness, ultimate tensile stress and yield stress estimation by sample-free indentation methods are shown. The weld metal hardness distribution in the transverse direction is homogeneous while from the top to the root an increase in hardness values at all welding speed modes is occurred. It was also revealed that both the hardness and strength of the weld metal grow with the rising welding speed, herewith the increase in these properties in the top of the weld is more significant than in the root. According to the analysis of the interrelation between structure and mechanical properties it was concluded that the main reason of mechanical properties fluctuations is a change in the weld metal chemical composition as a result of the volatile components evaporation during welding.