Which statement about the leg length and weld size of a concave fillet weld is true?

Which statement about the leg length and weld size of a concave fillet weld is true?

• A. The leg length is always larger than the weld size
• B. The leg length is always smaller than the weld size
• C. The leg length is not necessarily the same as the weld size
• D. The leg length equals the weld size

Answer: (C)

In concave fillet welds, the two dimensions you’re looking at—how long the weld is along the legs (the leg length) and how thick the weld is at its tightest point (the throat or weld size)—aren’t forced to match. When the weld has a concave profile, material is recessed inward, which reduces the throat thickness relative to the visible leg length. That means the smallest cross-section that actually carries the load (the throat) can be smaller than the leg length you measure along the weld faces. Because of this geometry, you can’t assume the leg length equals the weld size. The correct statement recognizes that these two measurements aren’t necessarily the same, especially with concave shapes. The other options imply a fixed relationship (always larger, always smaller, or always equal), which isn’t true given how concavity alters the weld’s cross-sectional throat.

In concave fillet welds, the two dimensions you’re looking at—how long the weld is along the legs (the leg length) and how thick the weld is at its tightest point (the throat or weld size)—aren’t forced to match. When the weld has a concave profile, material is recessed inward, which reduces the throat thickness relative to the visible leg length. That means the smallest cross-section that actually carries the load (the throat) can be smaller than the leg length you measure along the weld faces. Because of this geometry, you can’t assume the leg length equals the weld size. The correct statement recognizes that these two measurements aren’t necessarily the same, especially with concave shapes. The other options imply a fixed relationship (always larger, always smaller, or always equal), which isn’t true given how concavity alters the weld’s cross-sectional throat.