Which AWS Structural Welding Code should be followed for welding steel between 1/8 and 3/16 inch thick, inclusive?

The AWS D1.3 Structural Welding Code is specifically tailored for welding thin materials, particularly those with a thickness range of 1/8 inch to 3/16 inch. This code addresses issues related to the welding of sheet steel and focuses on the unique considerations that arise when working with thinner materials, including distortion and heat input control, which can be critical in maintaining the integrity of the weld.

While the codes such as AWS D1.1, D1.2, and D1.4 serve different purposes and target various material types and thicknesses within the structural welding sphere, they are not specifically designed for the specified range of thickness in this question. AWS D1.1 covers structural steel welds in general, D1.2 is tailored toward aluminum, and D1.4 focuses on lifting and load-bearing structures. Therefore, for the stated thickness of steel, AWS D1.3 is the appropriate reference, as it directly addresses the nuances of welding steel beams or plates within that specific thickness range.