What is the minimum size fillet weld permitted when joining a 1/2 inch thick plate to a 1 inch thick plate using E7018 SMAW low-hydrogen electrodes?

The minimum size fillet weld permitted when joining a 1/2 inch thick plate to a 1 inch thick plate with E7018 SMAW low-hydrogen electrodes is 3/16 inch. This dimension is based on the guidelines established in the American Welding Society (AWS) standards, which outline minimum weld sizes according to the thickness of the materials being joined.

A fillet weld's size is critical to ensure that it can adequately withstand the expected stresses and loads while providing sufficient penetration and reinforcement. In this specific scenario, the thicker plate's influence leads to the requirement of a minimum fillet weld size that accommodates the thicker section while ensuring structural integrity.

Choosing a fillet weld size that is too small may lead to weaknesses that could compromise the joint's strength. The 3/16 inch dimension strikes a balance between being compliant with the applicable codes and ensuring that the weld can effectively transfer loads between the plates.