How is the strength of a fillet weld determined?

How is the strength of a fillet weld determined?

• A. The length of the fillet weld's leg.
• B. The calculated area of the fillet weld.
• C. The effective throat thickness of the fillet weld.
• D. The fillet weld face, including convexity.

Answer: (C)

The strength of a fillet weld is determined by its throat, specifically the effective throat thickness. This is the shortest distance through which the weld material actually resists the load along the joint. The weld’s capacity per unit length is governed by this cross-sectional dimension, because the shear and tensile stresses concentrate there. The leg length or the overall face area does not directly define the resisting cross-section, and while the face shape (convexity) can alter the throat, the critical factor remains how thick that throat is. So, the effective throat thickness best reflects the weld’s strength.

The strength of a fillet weld is determined by its throat, specifically the effective throat thickness. This is the shortest distance through which the weld material actually resists the load along the joint. The weld’s capacity per unit length is governed by this cross-sectional dimension, because the shear and tensile stresses concentrate there. The leg length or the overall face area does not directly define the resisting cross-section, and while the face shape (convexity) can alter the throat, the critical factor remains how thick that throat is. So, the effective throat thickness best reflects the weld’s strength.