This article describes advanced techniques used in the repair and refurbishment of a platform combustion system (PCS) for an SGT5-8000H turbine. The first part outlines the refurbishment process of the part basket—a key PCS component—covering inspection, repair, recoating, and final assembly steps. The second part highlights the integration of advanced repair technologies, including laser-based cutting and welding, as well as patch repairs using 3D-printed parts via laser powder bed fusion.

The H-class turbine, introduced nearly a decade ago, has reached a significant milestone with its 100th global sale. With 108 units sold and 91 in operation across four continents, accumulating over 3.2 million fired hours, the SGT5-8000H has established itself as a market leader, setting industry benchmarks for performance. Since its launch, the SGT5-8000H's output has increased from 375 MW to 450 MW, and combined cycle efficiency has surpassed 62%. To maintain optimal performance, the platform combustion system (PCS) of the SGT5-8000H has undergone refurbishment in Berlin since 2017. Beginning with a PCS from Samsun, Turkey, the process involves a detailed inspection, repair, recoating, and final assembly. Advanced technologies, such as blue light scanning, enhance efficiency and enable lifecycle assessments. Innovative repair methods, including 3D printed patch repairs using laser powder bed fusion (LPBF), reduce costs. Laser-based cutting and welding automation further minimizes heat input and distortion, ensuring the PCS's reliability and longevity. These technological advancements contribute to the SGT5-8000H's stable and dependable operation.

Intensive R&D work of more than one decade has demonstrated many unique coating properties, particularly for oxide ceramic coatings fabricated by suspension thermal spraying technology. Suspension spraying allows producing yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC) with columnar microstructure, similar to those produced by electron-beam physical vapor deposition (EB-PVD), and vertically cracked morphologies, with a generally low thermal conductivity. Therefore, suspension sprayed YSZ TBCs are seen as an alternative to EB-PVD coatings and those produced by conventional air plasma spray (APS) processes. Nonetheless, the microstructure of the YSZ topcoat is strongly influenced by the properties of the metallic bondcoat. In this work, direct laser interference patterning (DLIP) was applied to texture the surface topography of Ni-alloy based plasma sprayed bondcoat. Suspension plasma spraying (SPS) was applied to produce YSZ coatings on top of as-sprayed and laser-patterned bondcoat. The samples were characterized in terms of microstructure, phase composition and thermal cycling performance. The influence of the bondcoat topography on the properties of suspension sprayed YSZ coatings is presented and discussed.

Over recent years, with the drive for new higher power, higher efficiency Gas Turbine engines, manufacturers have had to look at new alloys and new coating techniques to achieve and support the industry requirements. Repair technology has therefore had to keep pace with the OEM advances and much research and development has been undertaken in developing new repair processes. Many of the alloys now used are directionally solidified or single crystal, which until now have been deemed irreparable by traditional welding techniques. Recent developments in the use of lasers have not only rendered these alloys salvageable but have also reduced the overall repair time and therefore the cost. This paper looks at the use of laser technology as a repair process for gas turbine components, touching briefly on laser cutting and drilling but concentrating mainly on laser powder feed welding and its applications.

Paper presents a study of modeling and numerical simulation of laser engraving process. The 1-D simulation concerned CO 2 c.w. pulsed laser engraving of plasma sprayed alumina, titania and aluminum titanate coatings. These coatings will possibly replace the Cr 2 O 3 ones used currently in manufacturing of anilox rolls. The model was refined in comparison to the previous one (1) by taking into account the speed of the roll at the engraving. The actual thermophysical coefficients of plasma sprayed alumina, titania and aluminum titanate were input to the computations. The model enabled calculation of the engraving's depth in function of the principal laser treatment parameters viz. pulse length and laser power density. Finally, the overflow effect at the laser treatment of new ceramics was discussed and compared to that occurring at Cr 2 O 3 engraving.

Anilox rolls require dense, adherent chromium oxide coatings capable of the highest quality microfinishing and laser engraving. Process economy and high deposition rate are also essential. Increasingly, anilox roll job shops are spraying such coatings using a high power plasma system, prompting this detailed investigation of processes, powders, and finishing. This paper evaluates how the material and the process influence the finished texture and engraving quality. Criteria for a successful coating are defined. The effects of plasma process, powder type, and coating microstructure on finish and engraveability mc analyzed in detail and practical recommendations are made. The test matrix includes high power and conventional plasma spray systems, three commercial chromium oxide powders used in anilox roll spraying, and three commonly used finishing methods.

This paper presents a preliminary study of mathematical modeling and numerical simulation of laser engraving process. The 1-D simulation concerned CO 2 c. w. pulsed laser engraving of plasma sprayed Cr 2 O 3 coatings as used in the manufacture of anilox rolls. The thickness of the evaporated material was calculated as a function of laser processing parameters viz. pulse length and power density. The actual thermophysical coefficients of plasma sprayed chromia were used if available and the results of calculated thickness of evaporated layer are compared with the experimentally determined depth of engraved cells to estimate unknown coefficients of liquid chromia. Finally, the experimental effect of overflow was related to the calculated thickness of liquid layer. The experimental procedure of minimization of this effect is proposed.