During destructive testing of an open butt joint weld, the root of the weld should be on which surface of the bend?

During destructive testing of an open butt joint weld, the root of the weld should be on which surface of the bend?

• A. Face of the bend
• B. Inside surface of the bend
• C. Outside surface of the bend
• D. Through the bend

Answer: (A)

In this bend test, the goal is to stress the weld root so any defects at the root will show up under loading. When you bend a plate, the outer surface (the face of the bend) goes into tension while the inner surface is in compression. Placing the weld root on the face of the bend puts the root directly in the tensile zone, so any lack of fusion, porosity, or other root defects are driven open and can cause cracking. This makes the test sensitive to root quality and provides a clear indication of weld soundness. If the root were on the inside surface or through the bend, those areas would be under compression or not subjected to the critical tensile stress, making root defects harder to detect. Thus, the face of the bend is the correct position for the root in this destructive test.

In this bend test, the goal is to stress the weld root so any defects at the root will show up under loading. When you bend a plate, the outer surface (the face of the bend) goes into tension while the inner surface is in compression. Placing the weld root on the face of the bend puts the root directly in the tensile zone, so any lack of fusion, porosity, or other root defects are driven open and can cause cracking. This makes the test sensitive to root quality and provides a clear indication of weld soundness.

If the root were on the inside surface or through the bend, those areas would be under compression or not subjected to the critical tensile stress, making root defects harder to detect. Thus, the face of the bend is the correct position for the root in this destructive test.