CIMA Inspection
High Temp Hydrogen Assessment

Accurate Answers for Critical Decisions
CIMA uses advanced nondestructive examination techniques, including Ultrasonic Frequency Analysis, to successfully detect and mitigate damage caused by High Temperature Hydrogen Attack. We have more than 15 years of experience scanning for HTHA and have found this damage mechanism in many vessels and exchangers, saving our clients from a future catastrophic failure.

What Is HTHA?

High Temperature Hydrogen Attack is a type of material degradation that occurs when steel is exposed to atomic hydrogen under high temperatures and pressures. Under these conditions, hydrogen molecules break apart. The individual hydrogen atoms diffuse into the alloy and react with the carbon in the steel, forming methane.

The resulting methane molecules are too large to diffuse through steel, so they accumulate, forming high-pressure pockets. These methane bubbles connect to form micro-fissures at internal surfaces like grain boundaries and voids.

In more advanced stages of HTHA, groups of micro-fissures join together to form cracks, leading to decarburization. Decarburization is the loss of carbon from the steel, making the metal weaker and less ductile.


    Detecting HTHA

    Traditional inspection methods are ineffective at detecting early-stage HTHA. Ultrasonic Testing will detect HTHA only in the later stages, when the methane-induced voids or cracks have grown significantly. Unfortunately, by this time the decarburization process has dramatically reduced the strength of the steel.

    Ultrasonic Frequency Analysis is the best solution for detecting early-stage HTHA. Our technicians have been trained to recognize the unique velocity, frequency and backscatter patterns that are HTHA’s hallmarks.

    With CIMAs experienced technicians and advanced inspection methods, it is possible to detect HTHA before it propagates to alarming and dangerous levels.


      CIMA Inspection ~ Professional NDT Inspection Services
      5041 Spencer Highway, #701
      ​Pasadena, Texas 77505
      Phone: 832-288-4961  ~ or ~  Email: