When no dimension is provided on a welding symbol, what should be assumed about the joint?

When no dimension is provided on a welding symbol, it is generally assumed that the weld should completely penetrate the joint. This assumption ensures that the weld is sufficient to provide the necessary strength and integrity required for the application. Complete penetration is often desirable in structural applications where the joint's strength is critical.

The absence of a specified dimension indicates a reliance on the welder's judgment and the standard practices for the materials being joined, which often default to complete penetration unless otherwise specified. This understanding is crucial because it guides welders in achieving the intended performance characteristics of the weldment.

In contrast, the other potential assumptions, such as allowing for any size or limiting the weld to partial penetration, would not ensure the strength that is typically needed in many welding applications. Additionally, the suggestion that the joint should not be welded contradicts the purpose of the welding symbol, which is to indicate that a weld is required.