Rising compressor pressure ratios in advanced-frame gas turbines – including platforms such as the GE 9HA, and comparable high-efficiency units – have pushed late-stage compressor temperatures beyond 930°F (500°C). While this improves overall efficiency, it also accelerates oxidation of low-chrome steel components in compressor discharge and combustion-adjacent sections, creating a growing fleet-wide reliability concern that increasingly drives GE turbine maintenance and inspection strategies.

At elevated temperatures, oxidation forms on internal casing surfaces that are out of direct line of sight. Oxide scale forms, loses adhesion, and exfoliates during normal thermal cycling, in some cases even without unit operation. These liberated particles contribute to gas turbine spalling and broader gas turbine spallation mechanisms as debris migrates downstream. In affected units — including ge 9ha gas turbine, Siemens, and Mitsubishi fleets — this material can obstruct cooling passages, erode thermal-barrier coatings, and accelerate distress of blades (buckets), vanes, and other hot-gas-path components.

In practice, the issue is often first identified indirectly through premature distress or early replacement of Stage 1 turbine blades, rather than through direct observation of the casing surfaces where oxidation originates.

This degradation mechanism has been observed repeatedly on F-, G-, H-, and J-class machines operating at higher firing temperatures and is often only recognized after downstream damage has occurred. For many operators, the economic impact is driven by shortened maintenance intervals and unplanned intervention on first-stage hot-gas-path hardware. Extending Stage 1 bucket maintenance by even a single cycle is often sufficient to offset the cost of preventative mitigation.

Integrated Global Services (IGS) addresses this issue through field-applied High Velocity Thermal Spray (HVTS®), which prevents oxidation debris generation at the source by applying a protective cladding to susceptible casing surfaces. The approach has been technically evaluated and validated by all three major gas turbine OEMs.

HVTS is executed entirely within planned outages, without impact to the outage critical path, and can be applied during minor, HGP, or major outages, with the rotor installed or removed. Typical on-site scope duration is 6–10 days per unit, depending on access and scope.

IGS provides end-to-end, turn-key execution, including:

• Engineering guidance and surface preparation requirements
• On-site application and quality verification
• Protection of critical interfaces
• Full environmental, safety, and bio-waste management compliance

Field experience spans F-, G-, H-, and J-class units across North America, Latin America, APAC, and the Middle East, supporting fleets that include GE 9HA, Siemens, and Mitsubishi platforms. Cumulative operating experience now exceeds 200,000 hours, with post-outage borescope inspections and open-unit examinations consistently confirming long-term cladding integrity.

For any questions, please contact us or email [email protected].

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