What does the toe and root refer to in a welded joint?

• A. Toe is where the bead meets the base metal edges; root is the deepest portion at the joint base
• B. Toe is the weld face; root is the surface where bead starts
• C. Toe is the deepest portion at the joint base
• D. Toe is the base metal thickness; root is the filler metal depth

Answer: (B)

Understanding where the weld meets the base metal is key. The toe is the point along the edge of the weld where the weld bead blends into the base metal—the boundary at the sides of the weld. The root is the deepest part of the weld at the joint base, the point where the weld metal first fuses with the base metals inside the joint. This distinction is important because the toe affects the weld’s edge finish and penetration at the sides, while the root relates to the bottom interior of the joint.

The weld face is a different term—the exposed surface of the weld itself—and the root isn’t simply where the bead starts, but the deepest portion inside the joint.