According to CSA W59, if the leg lengths of a convex fillet weld are unequal, which one determines the weld size?

In the context of CSA W59, the determination of weld size when dealing with an unequal leg length in a convex fillet weld is based on the smaller leg. This is because the effective strength of the weld is primarily influenced by the leg that is shorter, as it can limit the overall load-carrying capacity of the weld. The smaller leg determines the weld size since it influences the penetration and fusion of the weld, which are critical factors for ensuring the structural integrity of the joint.

Using the smaller leg for defining weld size ensures that the weld is designed and executed to safely handle the stresses imposed upon it. This approach also helps to maintain uniformity and consistency in welding practices, as it provides clear guidelines for weld sizing in various applications, preventing situations that could lead to inadequate weld strength.

In cases where the larger leg might seem to be more advantageous, it doesn’t provide a definitive input on the capability of the weld to bear loads effectively. Therefore, specifying the smaller leg as the weld size is a conservative and widely accepted practice in the welding industry.