Wormhole

A tubular or worm-like pore extending counter to the solidification direction within the weld metal, caused by directed gas escape during rapid cooling. It represents a severe structural defect.

Drawing pores form when gases in the weld can no longer escape in time and, during solidification, create elongated, wormhole-like channels. This usually happens when cooling is too fast or when the shielding gas isn't properly applied. The weld loses significant cross-section and becomes prone to cracking. Keep cooling under control, ensure clean material and a proper gas shield, and you won't have this problem. If you see such pores, the part is usually scrap.

MetallurgieSchweißtechnik