What word completes the phrase 'the ____ of the weld' in the described test?

• A. toe
• B. root
• C. cap
• D. bead

Answer: (B)

In welding terminology, the root of the weld refers to the bottom inside portion where the weld first fuses with the base metal and forms the deepest point of penetration. It’s the part you assess when talking about root penetration and how the weld starts inside the joint. The cap is the top surface of the weld after deposition, the toe is the edge along the sides where the weld meets the base metal, and the bead is the deposited weld metal along the joint. So, the phrase fits best with the root, describing the foundational part of the weld where fusion begins.