Microscopic Joint Edge Flaw

A local imperfection on the prepared joint faces that remained un-melted after the welding process. It forms a potential initiation point for crack formation under load.

Microscopic lack-of-fusion defects occur when the edges don't melt properly and a fine gap remains at the root. That's dangerous because it acts like a notch and a crack can start there under load. So make sure the flanks are cleanly melted and there's enough heat to fully catch the edges. If you see the gap, you have to rework the spot and weld over it properly, otherwise the weld won't hold in the long run.

MetallurgieSchweißtechnik