What is a back weld as defined in the AWS D1.1?

A back weld, as defined in the AWS D1.1, is specifically a weld placed on the opposite side of a joint to reinforce it. This type of weld is typically used to enhance the integrity of the joint by providing additional support, thereby ensuring better load-bearing capacity and improved overall performance of the welded structure.

In practice, back welding is crucial in situations where a single-sided weld may not provide sufficient strength or durability. It helps in addressing potential defects and ensuring that the weld is more robust, particularly in applications subjected to significant stresses or forces.

The other options do not accurately capture the essence of a back weld. A weld applied only on the surface, for instance, does not encompass the reinforcement aspect intrinsic to back welds. A decorative weld that is added for aesthetics implies a different purpose, which is not structural integrity. Meanwhile, a weld that is not inspected contradicts the quality and safety standards upheld in welding practices. Inspections are key to ensuring that all welds, including back welds, meet the appropriate criteria for strength and durability.