What is the effect of inadequate penetration on a weld?

Inadequate penetration in a weld occurs when the weld metal does not sufficiently penetrate the joint or the base material, resulting in a fusion that is not deep enough to provide the necessary strength. This lack of penetration can lead to various structural weaknesses, including reduced load-bearing capacity and increased susceptibility to failure under stress. As a consequence, the weld may not be able to sustain the intended loads or withstand fatigue over time, potentially leading to catastrophic failures. Therefore, the correct assertion is that a weld with inadequate penetration will be weak, compromising the integrity of the weld joint it was intended to strengthen.

The other outcomes, such as a weld being too strong or visually appealing, are not associated with inadequate penetration. A weld that lacks sufficient penetration will not produce an aesthetically pleasing appearance; rather, it may contain blowholes or have a rough finish due to improper fusion. Additionally, it will not uniquely prevent corrosion, as weak welds may actually create areas vulnerable to corrosion due to insufficient material continuity and bonding.