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R-TECH Materials – A Reliable Partner for Safety Critical Industries

Whether it be supporting a plant outage inspection, condition assessment or a failure analysis investigation, R-TECH Materials is acutely aware of the importance of excellent customer service. Our staff are committed to providing superior service levels, no matter what day of the week it is.

Recently a key-client contacted R-TECH Materials for support in the assessment of suspected High Temperature Hydrogen Attack (HTHA) of a carbon steel process pipeline carrying highly flammable media. The client had found defect like indications during a non-destructive inspection, halting plant operations at a significant cost.

HTHA occurs when atomic hydrogen diffuses into the structure of a carbon steel material, in this instance the material from which the process pipeline was constructed. Carbon steel is essentially a composite material – a ductile matrix reinforced by strong carbide rich phases. Atomic hydrogen readily reacts with dissolved carbon and carbide rich phases within the steel, yielding methane (CH4). With time the carbide rich phases are gradually consumed; the material is said to have undergone decarburisation. This is accompanied by a loss of strength and increased ductility. This is further compounded by the fact that molecular methane is unable to diffuse out of the steel. Therefore, it results in the opening of intergranular fissures (Figure 1). The evolution of methane creates a localised partial pressure, effectively driving the fissure further open. In critical applications where the process media is flammable, such failure can have catastrophic consequences for plant operators, the environment and business continuity.

Early stages of HTHA

Figure 1  Early stages of HTHA

Detecting the early stages of HTHA by non-destructive means can prove very difficult, that said, defect indications are taken very seriously, especially when the process media is flammable. In order to examine the indications, sections were removed from the pipeline so that they could undergo metallographic assessment. The samples arrived on a Sunday with a request for 24-48 hour turnaround. R-TECH Materials mobilised staff through the weekend, issuing an interim report on the same day the samples were received. No instances of HTHA were observed meaning that the plant could return to operations with the minimum of disruption.

R-TECH Materials are focused on delivering fantastic service to our clients, no matter the industry or application. Failure investigations are generally concluded with 5-7 working days from the receipt of samples. Where required, a priority service can be offered to support our clients need. Our onsite services are available on a 24/7 basis globally.