Which of the following is an acceptable fillet weld profile?

The acceptable fillet weld profile in this context is slightly concave. A slightly concave profile refers to a weld that is slightly inwardly curved at the surface, which contributes to good fusion and strength within the welded joints. This profile effectively helps in distributing stresses and can reduce the risk of issues such as cracking, which could arise from other less favorable shapes.

In terms of industry standards, a slightly concave weld profile is typically preferred as it promotes better penetration into the base materials and ensures a more robust joint overall. Adherence to these practices helps maintain the structural integrity of welded components, which is paramount in any construction or fabrication process.

Other profiles, such as completely convex, flat with a sharp edge, or V-shaped, do not meet the same criteria for effective weld quality. Convex profiles may not provide adequate penetration or support for the weld joint, while flat profiles with sharp edges can lead to stress concentrations. V-shaped profiles, although sometimes used in specific applications, generally do not fall under the typical acceptable categories for fillet welds outlined in the structural welding code. Thus, choosing a slightly concave profile aligns with both good practice and regulatory standards in welding.