AWS Certified Welding Inspector (CWI) Practice Exam

The concept tested is how a fillet weld is extended when it runs around a corner. When a fillet weld continues around a corner of a member, the correct practice is to “box” the weld—that is, extend the fillet to form a box-like section around the corner. This boxing keeps the weld geometry consistent around the corner, preserving the effective throat and leg dimensions and providing a smooth, continuous weld across the corner rather than creating a weak, abrupt transition.

Backing, actual throat, and bevel refer to other aspects of welding: backing is a support behind the weld root, actual throat is the measured distance from the weld face to the root, and bevel is a groove prep for butt joints. They don’t describe the method of continuing a fillet weld around a corner like boxing does.