Groove weld size will always exceed the effective throat size for a partial joint penetration groove weld.

Groove weld size will always exceed the effective throat size for a partial joint penetration groove weld.

• A. True.
• B. False.
• C. Sometimes.
• D. Only for full penetration.

Answer: (B)

Groove weld size and effective throat are different quantities that describe different things about a weld. The groove weld size is the dimension used to specify the weld at the joint, essentially how large the weld is at the root, while the effective throat is the actual minimum cross‑section of weld that carries the load across the joint plane. In a partial joint penetration groove weld, the weld does not fully fuse to the opposite side. The amount of metal that actually resists shear (the effective throat) depends on the penetration and on any reinforcement above the root. If there is significant reinforcement, the cross‑section available to carry the load can be larger than the nominal groove size; if reinforcement is little or penetration geometry reduces the effective cross‑section, the throat could be smaller. Because the relationship isn’t fixed, you can’t say the groove weld size will always exceed the effective throat.

Groove weld size and effective throat are different quantities that describe different things about a weld. The groove weld size is the dimension used to specify the weld at the joint, essentially how large the weld is at the root, while the effective throat is the actual minimum cross‑section of weld that carries the load across the joint plane.

In a partial joint penetration groove weld, the weld does not fully fuse to the opposite side. The amount of metal that actually resists shear (the effective throat) depends on the penetration and on any reinforcement above the root. If there is significant reinforcement, the cross‑section available to carry the load can be larger than the nominal groove size; if reinforcement is little or penetration geometry reduces the effective cross‑section, the throat could be smaller. Because the relationship isn’t fixed, you can’t say the groove weld size will always exceed the effective throat.