In AWS D1.1, what is the permitted convexity for a single pass fillet weld with 8 mm leg size?

The permitted convexity for a single pass fillet weld with an 8 mm leg size as outlined in AWS D1.1 is indeed 3/16 inch. In AWS welding specifications, convexity refers to the outward bulge or protrusion of the weld bead beyond the theoretical shape of the weld.

The choice of 3/16 inch as the maximum acceptable convexity recognizes the practical aspects of weld appearance and functionality. Excessive convexity can lead to a range of issues, including stress concentrations that may affect the integrity of the weld joint under load. The guidelines aim to ensure that the weld bead maintains a balance between adequate reinforcement and overall geometry, preserving the mechanical properties and structural reliability.

By adhering to this specification, welders ensure that they maintain quality and performance standards set by AWS, which contributes to safer and more reliable welded structures.