Spot welding of Fe-Si-B Amorphous Metal Foil

Abstract

The possibility of the welding of amorphous metal foils was examined.
Fe₇₈Si₉B₁₃ amorphous metal foil having 20 microns in thickness was welded by using a stored energy type spot welding machine. This foil was possible to weld without crystallization at a welding time within 0.4 milliseconds.
The irregularity of weld nugget shape was due to the unevenness of the foil surfaces employed. This resulted in the scattering of tensile-shear strength of single spot welds.
Increasing weld time with the use of the capacitor bank having excessive capacitance led to a brittle weld nugget, though crystallization did not occur.
In tension-shear test, a crack initiated near the periphery of the weld nugget and propagated in the base metal. It means that the enhancement of joint strength was difficult by multiple spot welding.