In AWS D1.1, what type of reinforcement is preferred for welds in structural applications?

In AWS D1.1, the preferred type of reinforcement for welds in structural applications is convex. This preference relates to how the shape of the weld affects its mechanical properties and performance under loading conditions.

Convex welds are beneficial because they provide better distribution of stress across the weld and the base material. The curvature of a convex profile helps to minimize stress concentrations that can lead to cracking or failure, particularly in structural applications where weld integrity is crucial for the safety and durability of the construction. Additionally, a convex shape can enhance the flow of weld metal during the welding process, contributing to a stronger bond between the pieces being joined.

Concave and flat weld profiles do not inherently provide the same benefits in terms of stress distribution and can result in reduced performance under certain loading conditions. While all types of weld profiles may be acceptable under specific circumstances, AWS D1.1 specifically favors convex reinforcement as the optimal choice for most structural applications.