What is the minimum fillet weld size required for base metal thickness of 9/16"?

The minimum fillet weld size requirement is based on the thickness of the base metal being joined. According to AWS D1.1, the minimum size for a fillet weld typically corresponds to the thickness of the thinner part being welded, with specific guidelines provided in the code regarding the relationship between fillet weld size and base metal thickness.

With a base metal thickness of 9/16 inch, the code stipulates that the minimum fillet weld size should be computed as a proportion of the thickness. The standard guidance suggests that the minimum weld size is determined, rounding to the next applicable size if necessary, which leads to a recommended minimum fillet size of 1/4 inch for base metals thicker than 1/4 inch but less than 1/2 inch. However, for thicker base metals, 1/4 inch becomes the commonly referenced minimum size that can adequately ensure the weld's structural integrity without compromising its strength.

In this case, the requirement of 1/4 inch as the minimum size for a fillet weld for a 9/16 inch thick base metal aligns with the code requirements, ensuring sufficient weld strength to handle applicable loads. Much larger weld sizes would typically be specified for thicker materials or load demands, but for