Root defects in full penetration laser welding of thick plates using steady electromagnetic force

This article proposes an approach to stabilize the process of full-penetration laser welding of 16 mm 316L stainless steel by introducing steady electromagnetic force. Transient formation of root defects was captured by high-speed camera (CCD) and using the sandwich method. The stable and sustained welding process benefited from electromagnetic force, which weakened hydrostatic pressure at the bottom surface and altered the liquidity of the metal pool. Moreover, the electromagnetic force compensated for the insufficient surface tension and successfully prevented root defects such as sagging and drop-out.