Tetra In Action #9 - July, 2017

Grade 91 Damage Detection Methods

• HRSG Inspections:  Planned, periodic inspection of HRSG and associated steam cycle
• Balance of Plant is an essential component of a plant maintenance regime.
• Systematic visuling techniques, helps predict failures and direct preventative maintenance programsal inspection of pressure parts, gas path, steel structure, external piping and supports identifies early signs of damage in critical components, monitors degradation over time, and in conjunction with advanced analytical and model.
• Condition Assessments combine a review of plant design data and operating history with the results from unit inspections. They provide invaluable insight into whether there has been, or can have expected to have been, any significant deterioration in units condition, whether this is likely to be observed during visual inspection, identifying probable root causes and making recommendations for maximising unit reliability and operating life.  

Tetra Engineering has the experience and expertise that comes from having inspected virtually every type and configuration of thermal unit, operating mode and fuel type, from all the major OEMs, and as we do not offer boiler repair services or supply hardware, our advice will always be independent and objective.  

HRSG Inspection Planning Guide Snapshots    

Graphitization damage can occur at high temperature locations (not necessarily high stress) where metal temperatures are over 800F (425C) in carbon or carbon-molybdenum steel for long periods. The carbide phase in the steel is converted to graphite over time at the high temperature, reducing the strength and ductility of the material. It can occur in conjunction with the formation of creep voids, or without the presence of creep voids. In some instances, the result is excessive plastic deformation that results in gross bowing of tubes without failure.    

Bowed tubes with graphitization damage.  

If you are interested in the full version of the HRSG Inspection Planning Guide (2nd edition) contact Ms Christine Vallon at christine.vallon@tetra-eng.com.