BACKING RING
A RELATIVELY NARROW, CIRCULAR SECTION PLACED IN BACK OF A BUTTWELDED JOINT PRIOR TO MAKING THE ROOT PASS OF THE WELD. THIS IS DONE TO ACHIEVE A FULL-PENETRATION WELD WHEN THE BACK SIDE OF THE WELD JOINT CANNOT BE ACCESSED.
A RELATIVELY NARROW, CIRCULAR SECTION PLACED IN BACK OF A BUTTWELDED JOINT PRIOR TO MAKING THE ROOT PASS OF THE WELD. THIS IS DONE TO ACHIEVE A FULL-PENETRATION WELD WHEN THE BACK SIDE OF THE WELD JOINT CANNOT BE ACCESSED.