Session: 30-11 Testing 2 and Systems 2

Submission Number: 178777

Mechanical Behavior of a Power Generation Steel Subjected to Thermo-Mechanical Service-Like Testing With Supercritical Co2 Exposure 

The accurate prediction of life expenditure in axial expanders operating within power plants has become increasingly critical, especially in the context of modern energy systems. These components are now frequently subjected to rapid load changes and elevated temperatures, driven by the evolving demands of the energy market. Reliable life prediction directly impacts operability and availability, enabling faster start-ups and extended maintenance intervals.

To address these challenges, recent efforts have focused on the design of increasingly sophisticated “service-like” tests that replicate real-world strain and temperature profiles. However, the transition toward advanced energy cycles—particularly those employing supercritical carbon dioxide (sCO₂)—introduces additional degradation mechanisms such as corrosion and carburization, which must be accounted for in life assessment methodologies.

This work presents a comprehensive approach to this problem, beginning with the development of customized test specimens and a dedicated testing campaign aimed at evaluating the degradation of creep and fatigue properties under high-temperature sCO₂ exposure. Finite Element (FE) simulations were employed to optimize specimen geometry and ensure representative stress and temperature distributions.

A key contribution of this study is the formulation of a visco-plastic material model tailored to capture the complex time-dependent behavior observed during testing. In parallel, a novel damage accumulation rule was developed to accurately reflect the combined effects of mechanical loading and environmental attack. These models form the theoretical foundation for interpreting test results and predicting component life under realistic service conditions.

Presenting Author: Federico Bucciarelli Nuovo Pignone Tecnologie s.r.l

Presenting Author Biography: Federico Bucciarelli received his Master Degree in Mechanical Engineering from the University of Pisa in 2013 and a second-level diploma from Sant'Anna School of Advanced Studies in 2014. He is pursuing a PhD in Industrial Engineering under the supervision of prof. Bernardo Disma Monelli. At the same time, he works as Senior Mechanical Engineer at Baker Hughes, leveraging over a decade of experience in product design and engineering. His career spans roles in steam turbine design, predictive maintenance analytics, and thermomechanical assessments, with a strong foundation in FEA and mathematical modeling. Federico has played a role in New Product Development programs and has a rich background in both engineering development and technical innovation. His work reflects a deep commitment to advancing energy technologies through good engineering and data-driven solutions.

Authors:

Federico Bucciarelli Nuovo Pignone Tecnologie s.r.l
Alessandro Guazzini Università di Pisa, Dipartimento di Ingegneria Industriale
Giuseppe Macoretta Università di Pisa, Dipartimento di Ingegneria Industriale
Bernardo Disma Monelli Università di Pisa, Dipartimento di Ingegneria Industriale
Damaso Checcacci Nuovo Pignone Tecnologie s.r.l