What term describes a weld discontinuity where fusion did not occur between the weld metal and adjoining surfaces?

The term that describes a weld discontinuity where fusion did not occur between the weld metal and adjoining surfaces is known as incomplete fusion. In welding, achieving a proper bond between the weld material and the base metal is essential for the strength and integrity of the weld joint. Incomplete fusion indicates that there has been insufficient heat or time during the welding process, preventing full melting and bonding of the materials involved.

This phenomenon can lead to significant weaknesses in the weld, making the joint more susceptible to failure under stress. It is important for welders to monitor their technique and parameters carefully to avoid this issue, ensuring that the weld penetrates adequately into the base metals and forms a solid connection. Understanding incomplete fusion helps in diagnosing weld quality issues and taking corrective actions in the welding process.