What is the prohibited size for fillet welds according to the AWS D1.1 code?

In the AWS D1.1 code, the limitation on fillet weld sizes is an essential aspect to ensure the structural integrity and safety of welded connections. The code specifies that fillet welds must generally be sized appropriately for the types of joints and the materials being welded.

Fillet welds that exceed a certain dimension can lead to potential issues such as lack of penetration, undercutting, or even failure to meet the needs of fatigue resistance in structural applications. The code typically allows for maximum size limits based on thicknesses of the base metals being joined.

In assessing the choices provided, it’s noted that a 3/16” fillet weld is often outside of the acceptable range dictated by the code for certain applications and is commonly referenced as a problematic size due to the increased likelihood of defects in weld quality when approaching the upper limits. Smaller welds, like 1/8” and appropriately sized 1/4” welds, are usually permitted depending on the specific conditions and joint designs outlined in AWS D1.1.

Thus, the selection of 3/16” as a prohibited size aligns with the guidance that emphasizes adherence to defined limits for fillet welds, ensuring optimal performance in structural applications.