What is a weld made specifically to hold pieces of a structure in proper alignment until final welding is completed called?

The term for a weld specifically designed to hold pieces of a structure in proper alignment until the final welding can be completed is known as a tack weld. This type of weld is typically a small, temporary weld that prevents movement of the workpieces during the welding process. Tack welding is crucial because it helps maintain the integrity of the joint and ensures that everything remains in the correct position, thus facilitating a smoother and more precise final welding operation.

Tack welds are often used in assembling larger components where the parts may shift or deform under the heat of the welding process. By securing these parts in place initially, the welder can then proceed to complete the more substantial and permanent welds, knowing that the alignment has been preserved. This practice is standard in various welding applications, including MIG welding, to enhance both accuracy and efficiency.