Corrosion Under Insulation (CUI) Inspection

    The following photo shows CUI (corrosion under insulation) guided wave testing. The MsS probe was installed after removing the insulation and tested at 32, 64, and 128 kHz. The small surface cor¬rosion was sensitive to a high frequency of 128 kHz (Wave length is 1 inch). Pitting corrosion was found in the elbow region and verified by the client after removing the insulation.