Drive, fly or roll with electrons
Process Example "Turbo Charger"
For application shown below different electron beam specific processes were used. To weld the material combination nickel base alloy and carbon steel, a so called Black and White Joints (BWJ), an exact positioning and high cooling rates are required to avoid hot cracks. Additional the distortion should be reduced to a minimum.
The exact positioning of the beam can be realized with a high accurate SEM view. To avoid the distortion and and minimize reconditioning 4 spot welds were applied.
After the welding process the results can be observed. If necessary a so called cosmetic weld can be applied to smooth the surface even more.
To increase the hardness of the bearing seats electron beam hardening was used. With this technique the surface can be hardened up to 1600 HV0.1 depending on the used material.
The result is a defect- and distortion-free dissimilar weld.
Examination of the Weld
Electron Beam Welding is one of the widely used processes in industries for joining dissimilar materials. Due to the very fine beam (less than 100µm) and the ability of an exact beam positioning using the SEM mode, the composition of the melt can be controlled. This avoids incomplete side wall fusion and an uncontrolled growth of inter metallic phases which would lead to cracks. In (b) you see some examples of dissimilar welds: aluminum to copper, aluminum to steel and nickel-base-alloy to carbon steel.
Al to Cu
Black and White Joint (BWJ)
Al to Steel