High temperature hydrogen attack (HTHA) is a phenomenon which occurs within some industrial processes when the presence of hydrogen, subjected to high temperature and pressure, makes plants and systems susceptible to damage. This reaction can cause an industrial plant to suffer serious failure, which may lead to both expensive repairs and loss of production.
HTHA can be detected in a number of ways, but it is considered that with the complexity of HHTA a more structured approach is necessary. A series of procedures have been developed featuring the latest advances in ultrasonic imaging and data processing techniques in order to achieve a greater level of confidence in both HTHA inspection results and inspection repeatability.
With a full understanding of both the phenomena and the methods to assess it, we feel our HTHA service will help minimize your risk. Our experienced technicians are able to efficiently evaluate the presence of hydrogen damage and so prevent failure of critical plant equipment. The information recorded can be later on analyzed allowing fitness for service calculations.
TÜV Rheinland Sonovation is part of the TÜV Rheinland Group specialized in providing a complete range of advanced non-destructive testing (NDT) services. In addition to operating a competence center for advanced NDT based in the Netherlands, it maintains branches in the United Kingdom, Belgium, Germany and Saudi Arabia. Acknowledged as leaders in the field, TÜV Rheinland Sonovation invests heavily in R&D and operates an accredited training school for advanced NDT as well as offering its expert services globally.
Using our HTHA services you get:
The backscatter technique is used to detect suspicious areas affected by hydrogen attack. The front of the attack in the material can be measured and imaged. The remaining wall thickness (un-attacked) is assigned a color. Using this technique the operator is able to create backscatter patterns and evaluate directional and frequency dependence.
Velocity ratio measurement
Velocity ratio measurement, on the other hand, is used as a cross-check to confirm the findings of the backscatter measurement. It is based on the principle that the longitudinal and transverse sound velocities are affected by HTHA. This way the percentage of attack can be measured and even a differentiation between small inclusions and HTHA is possible.
Time of flight diffraction (Tofd)
With time of flight diffraction (Tofd) testing it is possible to inspect structures for defects caused by HTHA. It can be used for the detection of both macro and micro cracks
Backscatter and velocity ratio measurement are used for the inspection of the parent material. Time of flight diffraction is used for the inspection of the weld material.