In welding terminology, what does "penetration" mean?

Penetration refers to the depth that molten metal reaches into the base metal during the welding process. A proper level of penetration is crucial because it ensures that the welded joint has sufficient fusion between the filler metal and the base material, which contributes to the strength and integrity of the weld. Inadequate penetration can lead to weak joints that may fail under stress. This term is vital for welders to understand as it directly impacts the quality and performance of the weld, as well as the overall structure's reliability.

Other terms like the depth of the weld bead, strength of the weld joint, or cooling rate of the weld refer to different aspects of the welding process and do not specifically capture the meaning of penetration in the context of achieving an effective weld.