Ultrasonic Detection, Characterization, and Quantification of localized High Temperature Hydrogen Attack in Weld and Heat-affected Zone

摘要

This paper presents the latest development and application of advanced ultrasonic techniques for inspecting steel welds and heat-affected zone (HAZ) for localized high temperature hydrogen attack (HTHA). The localized HTHA can be detected when it is still in its early fissuring stage, i.e., before any macrocracks are formed, by using high-frequency, angle-beam (such as 10 MHz, shear wave) transducers. All the detected signals can be discriminated in the frequency domain by using an angle-beam spectrum analysis (A)SA technique to differentiate HTHA fissures from other defects. The identified HTHA can then be sized by employing crack sizing techniques using the same high-frequency transducers as for the detection and characterization of HTHA fissures. These techniques have been used with successful results in field inspections. Examples of the field inspection results are provided.