UT of dissimilar (bimetallic) weld by horizontally polarized shear (SH-) waves demonstration of their benefits by comparison with standard UT techniques

The UT of bimetallic and austentic welds is strongly complicated by a high degree of elastic anisotropy and the coarse grain structure of the weld material and buttering. Due to these facts using standard UT-techniques only the HAZ's are inspected having access from both sides. In many cases bimetallic welds are only accessible from one side. Therefore techniques are necessary which are capable to inspect the whole weld even if there is only access from one side. Horizontally Polarized Shear-waves (SH-waves) are less affected by the mentioned effects than other wave modes. They have the capability of penetration of the weld metal, the buttering and also the cladding on the ferritic side.