NEED FOR ELECTRON BEAM WELDING(EBW) PROCESS
The major advantage resulting from the use of a vacuum environment with a working pressure of from 10-5 to 10-3 mbar is especially suitable for welding reactive materials. The absence O2, H2 and N2 in the weld zone ensures high quality and purity of the joint. Due to the capability of low distortion with minimal heat input (app. 0.8 kJ I cm) and the possibility to join even the finish machined and intricate parts, this process is most preferred. The highly concentrated beam permits a low energy input to the material, which minimises distortion and thermal effects on the materials.
The high power density is in the range of 1010 to 1013 W I m2. In addition, very intensive local heat resulting in a deep, narrow penetrating type of fusion weld lead to high depth to width ratio (50:1). The narrow fusion and heat affected zone lead to two main metallurgical advantages, namely reduced incidence of cracking during and after welding and improved weld properties because of reduced metallurgical damage.ustrial process.