What does the term "penetration" refer to in welding?

The term "penetration" in welding specifically refers to the depth of the weld metal that has fused into the base metal. This is crucial because adequate penetration ensures a strong bond between the welding material and the workpieces being joined. Proper penetration contributes to the overall integrity and strength of the weld, allowing it to withstand various stresses and loads.

When penetration is insufficient, the weld may be weak, leading to potential failure under stress. Conversely, excessive penetration can also lead to other issues, such as burning through the base material. Therefore, achieving the right level of penetration is a key skill for welders to master, as it directly impacts the welding quality and performance of the joint.