bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the Role of DNA Methylation Located in Cuproptosis-Related Genes: Implications for Prognosis and Immune Landscape in Hepatocellular Carcinoma
Authors: Zhu Rui , Wang Xue , Sun Fenyong , Zhu Liucun , Guo Wenna
Published: March 2024

Background: Copper dysregulation has been linked to liver disease, cardiac dysfunction, neuropathy, and anemia. Previous investigations have been undertaken to demonstrate the impact of cuproptosis-related genes (CRGs) on the poor prognosis of hepatocellular carcinoma (HCC), while the prognostic significance and beneath molecular basis of DNA-methylation sites located in CRGs remain unknown. This study aims to identify CRG-located DNA-methylation sites linked to patient prognosis and establish a novel prognostic biomarkers combination for CRG-located DNA-methylation signature. Methods: The prognostic biomarkers combination was established through multivariate-Cox-regression after CRG-located DNA-methylation sites tied to the outcome of patients emerged by univariate-Cox-regression. The correlation between signature and immune cell infiltration levels, immune-checkpoint-associated genes was analyzed using spearman correlation and the difference was contrasted between different groups utilizing the Mann-Whitney-U test. Real-time quantitative methylation-specific polymerase chain reaction (RT-qMSP) was used to identify gene methylation. Results: A novel prognostic biomarkers combination for CRG-located DNA-methylation signature was established. Subsequently, the independence of this methylation signature from clinical features and its correlation with immune infiltrative and immune checkpoints in HCC were also investigated. DNA methylation alterations can influence the onset, development, and treatment of various tumors by regulating the transcription of corresponding genes. Our analysis found that cg05706061 contained in prognosis signature was located in the promoter region of the cuproptosis-related gene SLC31A2. The DNA-methylation level of cg05706061 demonstrated significantly different between tumor and normal tissue, and significantly correlated with the expression of SLC31A2. We further investigated the promoter methylation status of SLC31A2 by qMSP, the result showed that the DNA-methylation level of SLC31A2 in HCC cell lines were significantly decreased compared with normal liver cells. Conclusions: Our findings reveal possible mechanisms of CRG-located DNA-methylation on the advancement of HCC and offers new perspectives for prognostic assessment and treatment options.
TINJAUAN ATAS PENGAWASAN KERJA PADA PROSEDUR KEPABEANAN IMPOR EMAS
Authors: Nurcahyo Marsanto Adi , Utomo Nurul Budi
Published: March 2024

Kegiatan impor emas mempunyai peran yang signifikan dalam perdagangan internasional yang dilakukan oleh Indonesia. Berdasarkan nilainya, emas termasuk dalam 10 besar komoditi yang diimpor Indonesia. Hal ini menjadi penting untuk memastikan dilaksanakannya prosedur kepabeanan impor pada kegiatan impor emas. Rumusan masalah dalam penelitian ini adalah bagaimana proses pelayanan kepabeanan impor emas serta bagaimana pengawasan kerja yang dilakukan dalam pelayanan kepabeanan. Penelitian ini menggunakan metode penelitian kualitatif deskriptif. Data didapatkan melalui kegiatan wawancara atau in-depth interview dengan para pemangku kepentingan. Berdasarkan hasil wawancara, pengawasan kerja yang dilakukan pimpinan organisasi tidak hanya pada kegiatan impor emas, namun pada keseluruhan kegiatan di kantor. Hasil penelitian menunjukkan bahwa Kantor Pelayanan di lingkungan Direktorat Jenderal Bea dan Cukai telah melakukan prosedur pelayanan kepabeanan untuk impor emas sesuai ketentuan. Pimpinan organisasi dalam hal ini manajemen kantor juga telah melakukan pengawasan kerja dengan baik. Hal ini terbukti dengan adanya pengawasan yang dilakukan sebelum kegiatan, saat kegiatan dan setelah kegiatan
DAMPAK SUBSIDI ONGKOS ANGKUT DI LAUT TERHADAP DISPARITAS HARGA BARANG KEBUTUHAN POKOK ANTAR DAERAH
Authors: Harahap Poltak Pramah Utama , Adrison Vid
Published: March 2024

Fenomena yang terjadi di Indonesia sebagai negara kepulauan adalah biaya transportasi laut antarpulau lebih mahal daripada biaya transportasi laut ke luar negeri. Biaya transportasi laut antarpulau yang mahal menyebabkan terjadinya disparitas harga barang kebutuhan pokok antar daerah di Indoensia. Penelitian ini hadir untuk menguji apakah benar kebijakan subsidi ongkos angkut di laut dapat menurunkan disparitas harga antar daerah. Peneltian disparitas harga antara daerah baik di skala nasional dan internasional berusaha untuk melihat faktor-faktor yang mendorong terjadinya konvergensi harga antar daerah seperti biaya transportasi, daya beli masyarakat, konektivitas di darat dan volume perdagangan. Hasil estimasi penelitian ini menunjukkan subsidi ongkos angkut menyebabkan disparitas harga di daerah yang dilalui Tol Laut setelah pelaksanaan kebijakan lebih rendah dibandingkan sebelum pelaksanaan dan lebih rendah dibandingkan daerah yang tidak dilalui Tol Laut. Biaya transportasi, densitas jalan dan volume perdagangan adalah faktor-faktor yang signifikan mempengaruhi disparitas harga di daerah-daerah di kawasan Indonesia Timur sedangkan kapasitas ekonomi  dan daya beli masyarakat adalah variabel yang signifikan mempengaruhi disparitas harga di daerah-daerah di kawasan Indonesia Barat.
Distopik Anlatıların Dilinden Masalsı Yankılar: Toplumsal Eleştiri ve İroni
Authors: Soydaner Ayşegül
Published: March 2024

Distopya, kurgusal bir gelecekte insanlık için karanlık, baskıcı ve çarpık bir toplum düzenini ele alan eserlerdir. Masallar ise genellikle fantastik ögeler içeren öğretici mesajlar taşıyan hikâyelerdir. Masallar ve distopik anlatılar arasındaki ilişki, distopik anlatılarda bazen masalsı ögelerin kullanılmasıyla ortaya çıkar. Masalsı ögeler, distopya içerisinde fantastik unsurları temsil ederek okuyucuya bir kaçış sunabilir veya sorunları abartarak eleştiri yapabilir. Distopik anlatılar ise toplumsal sorunlarla ilgilidir ve genellikle otoriter rejimler, eşitsizlik, özgürlük kısıtlamaları ve insan doğasının bozulması gibi konuları ele alır. Bu tür eserler, toplumsal eleştiri yaparak okuyucuya mevcut sorunları göstermeye çalışır. İroni, distopik anlatılarda sıklıkla kullanılan edebî bir araçtır. İroni; distopyanın çelişkilerini, paradokslarını ve absürtlüklerini vurgulamak için kullanılır. Distopik dünyadaki ironik durumlar, okuyucunun toplumsal sorunları daha derinden anlamasına ve sorgulamasına yardımcı olur. Distopik anlatılarda masalsı ögeler genellikle fantastik varlıklar, büyülü nesneler veya fantastik mekânlarla temsil edilirler. Bu ögeler, distopik dünyadaki gerilimi hafifletmek veya alternatif bir perspektif sunmak amacıyla kullanılabilir. Bu çalışma, distopya ve masal olmak üzere iki farklı edebî türün hayal gücü ve metafor kullanımına dayanarak toplum üzerindeki etkisine dikkat çekmekle beraber toplumsal eleştiriye de ironik bir bakış açısı sunmaktadır.
Legislative methods and means of establishing the truth on the fact of a crime committed in the Ancient Russian state of the 10th – 15th centuries: God’s judgments
Authors: Vasilchenko Denis , Gusev Vladimir , Samodelkin Alexander
Published: March 2024

The article presents the results of the historical and legal analysis of the legislative acts of the ancient Russian state of the 10th-1Sth centuries regulating the process of judicial proceedings on the fact of a crime committed. Such methods of establishing the truth in the case as God’s judgments are investigated: the trial with iron and water, the oath, the judicial duel, the judicial lot. The authors came to the conclusion that the appearance of God’s courts in the ancient Russian state, as methods of judicial proceedings, is the result of the search for ways and means of a fair resolution of the criminal law conflict.
The Russian Orthodox Church and the state in the 1970s – 1990s: the evolution of relationships
Authors: Bogdanova Elina , Klychnikov Yuriy , Kolesnikov Ilya , Kasparyan Konstantin
Published: March 2024

This article is devoted to the understanding of bilateral relations between the Russian Orthodox Church and government bodies in the 1970s - 1990s. Authors analyze the relationship between church and state in the late Soviet period and in the first decade of the existence of the Russian Federation. The article examines the transformation of the policy of state structures in relation to the Orthodox religion - from the desire to subjugate the Russian Orthodox Church to a constructive dialogue. Authors examine a set of problems that the Russian Orthodox Church faced during the period under review and the degree of assistance provided to it by the Soviet, and then the Russian federal authorities.
Internal Migration in Nepal: Resilience to Departure and Host Area
Authors: Karki Parbata Devi
Published: March 2024

The present study aims to explain the current situation of internal migration and resilience. It is based on secondary sources of information. Mixed method is used to depict the complex scenario of inter-regional migration. Internal migration is a common phenomenon in Nepalese social history. It is generally attributed to poverty, low income, scarce fertile land, lack of opportunity, disparity of population distribution and resources. The unnatural flow of population from hilly to Tarai and rural to urban areas is an issue of study. Migration creates an unprecedented challenge to modern society. The resilience of society either to the host area or the place of departure being painful. The issue of mobility of the people generates disparities of population distribution and resources. Due to uncontrolled movement of people either temporarily or permanently, balanced social and cultural issues are being destroyed and several complexities are emerging. Ancient migration pattern was guided by the scarcity of food and security. Current migration issues are governed by the luxuries of life. Over pressure of population in Tarai and urban areas and dearth of people in hilly region creates havoc in life of both the places.
Progress of China 700°C USC Development Program
Authors: Sun Rui , Cui Zhanzhong , Tao Ye
Published: March 2024

This paper presents an overview of China’s electric power development and the National 700°C Ultra-Supercritical (USC) Coal-Fired Power Generation Technology Innovation Consortium. Besides, the R&D plan and latest progress of China 700°C USC coal-fired power generation technology is also introduced in this paper.
Advanced USC Technology Development in Japan
Authors: Fukuda Masafumi , Saito Eiji , Semba Hiroyuki , Iwasaki Jun , Izumi Sakae , Takano Shinichi , Takahashi Takeo , Sumiyoshi Yasuo
Published: March 2024

We have reported on the effort being done to develop the A-USC technology in Japan, which features the 700 deg-C steam condition, since the 2007 EPRI conference. Our 9 year project began in 2008. There have been some major changes in the electricity power market in the world recently. At first, the earthquake changed the power system violently in Japan. Almost all nuclear power plants have been shut down and natural gas, oil and coal power plants are working fully to satisfy the market's demands. In the USA, the so called ‘Shale gas revolution’ is going on. In Europe, they are working toward the target of reducing CO2 emissions by the significant use of renewables with the backup of the fossil fuel power systems and enhancing power grids. A very rapid increase in power generation by coal is being observed in some countries. Despite some major changes in the electric sector in the world and the CO2 problem, the global need for coal power generation is still high. We can reconfirm that the improvement of the thermal efficiency of coal power plants should be the most fundamental and important measure for the issues we are confronting today, and that continuous effort should be put towards it. Based on the study we showed at the 2007 conference, we developed 700 deg-C class technology mainly focusing on the material and manufacturing technology development and verification tests for key components such as boilers, turbines and valves. Fundamental technology developments have been done during the first half of the project term. Long term material tests such as creep rupture of base materials and welds will be conducted for 100,000hrs continuing after the end of the project with the joint effort of each participating company. Today, we are preparing the plan for the second half of the project, which is made up of boiler components test and the turbine rotating tests. Some boiler superheater panels, large diameter pipes and valves will be tested in a commercially operating boiler from 2015 to 2017. The turbine rotor materials which have the same diameter as commercial rotors will be tested at 700 deg-C and at actual speed.
Current Status of the U.S. DOE/OCDO A-USC Materials Technology Research and Development Program
Authors: Shingledecker J. , Purgert R. , Rawls P.
Published: March 2024

The United States Department of Energy (U.S. DOE) Office of Fossil Energy and the Ohio Coal Development Office (OCDO) have been the primary supporters of a U.S. effort to develop the materials technology necessary to build and operate an advanced-ultrasupercritical (A-USC) steam boiler and turbine with steam temperatures up to 760°C (1400°F). The program is made-up of two consortia representing the U.S. boiler and steam turbine manufacturers (Alstom, Babcock & Wilcox, Foster Wheeler, Riley Power, and GE Energy) and national laboratories (Oak Ridge National Laboratory and the National Energy Technology Laboratory) led by the Energy Industries of Ohio with the Electric Power Research Institute (EPRI) serving as the program technical lead. Over 10 years, the program has conducted extensive laboratory testing, shop fabrication studies, field corrosion tests, and design studies. Based on the successful development and deployment of materials as part of this program, the Coal Utilization Research Council (CURC) and EPRI roadmap has identified the need for further development of A-USC technology as the cornerstone of a host of fossil energy systems and CO2 reduction strategies. This paper will present some of the key consortium successes and ongoing materials research in light of the next steps being developed to realize A-USC technology in the U.S. Key results include ASME Boiler and Pressure Vessel Code acceptance of Inconel 740/740H (CC2702), the operation of the world’s first 760°C (1400°F) steam corrosion test loop, and significant strides in turbine casting and forging activities. An example of how utilization of materials designed for 760°C (1400°F) can have advantages at 700°C (1300°F) will also be highlighted.
A Steam Generator for 700C to 760C Advanced Ultra-Supercritical Design and Plant Arrangement: What Stays the Same and What Needs to Change
Authors: Weitzel Paul S.
Published: March 2024

Increasing the efficiency of the Rankine regenerative-reheat steam cycle to improve the economics of electric power generation and to achieve lower cost of electricity has been a long sought after goal. Advanced ultra-supercritical (A-USC) development for materials to reach 760C (1400F) is a goal of the U.S. Program on Materials Technology for Ultrasupercritical Coal-Fired Boilers sponsored by the United States (U.S.) Department of Energy and the Ohio Coal Development Office (OCDO). As part of the development of advanced ultra-supercritical power plants in this program and internally funded programs, a succession of design studies have been undertaken to determine the scope and quantity of materials required to meet 700 to 760C (1292 to 1400F) performance levels. At the beginning of the program in 2002, the current design convention was to use a “two pass” steam generator with a pendant and horizontal tube bank arrangement as the starting point for the economic analysis of the technology. The efficiency improvement achieved with 700C (1292F) plus operation over a 600C (1112F) power plant results in about a 12% reduction in fuel consumption and carbon dioxide emissions. The reduced flue gas weight per MW generated reduces clean up costs for the lower sulfur dioxide, nitrogen oxides and particulate emissions. The operation and start up of the 700C (1292F) plant will be similar in control methods and techniques to a 600C (1112F) plant. Due to arrangement features, the steam temperature control range and the once through minimum circulation flow will be slightly different. The expense of nickel alloy components will be a strong economic incentive for changes in how the steam generator is configured and arranged in the plant relative to the steam turbine. To offer a view into the new plant concepts this paper will discuss what would stay the same and what needs to change when moving up from a 600C (1112F) current state-of-the-art design to a plant design with a 700C (1292F) steam generator and turbine layout.
Microstructural Evolution in Cast Haynes 282 for Application in Advanced Power Plants
Authors: Yang Y. , Thomson R. C. , Leese R. M. , Roberts S.
Published: March 2024

A global movement is pushing for improved efficiency in power plants to reduce fossil fuel consumption and CO2 emissions. While raising operating temperatures and pressures can enhance thermal efficiency, it necessitates materials with exceptional high-temperature performance. Currently, steels used in power plants operating up to 600°C achieve efficiencies of 38-40%. Advanced Ultra Supercritical (A-USC) designs aim for a significant leap, targeting steam temperatures of 700°C and pressures of 35 MPa with a lifespan exceeding 100,000 hours. Ni-based superalloys are leading candidates for these extreme conditions due to their superior strength and creep resistance. Haynes 282, a gamma prime (γ′) precipitation-strengthened alloy, is a promising candidate for A-USC turbine engines, exhibiting excellent creep properties and thermal stability. This research investigates the microstructural evolution in large, sand-cast components of Haynes 282. Microstructure, referring to the arrangement of grains and phases within the material, significantly impacts its properties. The research examines the alloy in its as-cast condition and after various pre-service heat treatments, aiming to fully identify and quantify the microstructural changes. These findings are then compared with predictions from thermodynamic equilibrium calculations using a dedicated Ni alloy database. The research reveals that variations in heat treatment conditions can significantly affect the microstructure development in Haynes 282, potentially impacting its mechanical properties.
Material Advancements for 700°C A-USC-Power Plants in China
Authors: Liu Zhengdong , Bao Hansheng , Yang Gang , Xu Songqian , Wang Qijiang , Yang Yujun
Published: March 2024

This paper briefly introduces the state-of-the-art of the research and development of candidate heat resistant materials used for the manufacturing of 700°C advanced ultra-super-critical (AUSC) fossil fuel power plants (PP) in China, especially, focus on the impressive progress in the past three years. The detailed advancements (technical exploration and industrial investigation) of candidate materials spectra for the boiler system of A-USC PP will be presented in the current paper, including novel ferritic heat resistant steels, advanced austenitic heat resistant steels, Fe- Ni-based alloys and Ni-based alloys, which serve and cover the steam temperature scope from 600°C to 720°C. Some newly available data associated with above materials will be released.
Manufacturing Demonstration of Inconel Alloy 740H for A-USC Boilers
Authors: Baker B. A. , Gollihue R. D. , deBarbadillo J. J. , Patel S. J. , Maitra D.
Published: March 2024

Inconel alloy 740H was specifically developed for use in coal-fired AUSC boilers. This alloy displays a unique combination of steam and coal-ash corrosion resistance, microstructure stability, creep strength and heavy section weldability. During the past two years Special Metals and Wyman-Gordon have undertaken an intense effort to demonstrate their capability to manufacture full-size boiler components, characterize their properties and simulate field assembly welds. This work was performed according to the requirements of ASME Boiler Code Case 2702 that was recently issued. This paper covers manufacturing of tube and pipe products and property characterization including recent data on the effect of long time exposure on impact toughness of base and weld metal. New data will also be reported on coal ash corrosion of base metal and weld metal. An overview of welding studies focused on integrity of circumferential pipe joints and a discussion of remaining technical issues will be presented.
Evaluation of High Temperature Strength of a Ni-Base Alloy 740H for Advanced Ultra-Supercritical Power Plant
Authors: Zhang Shengde , Takahashi Yukio
Published: March 2024

High temperature strength of a nickel-based superalloy, Alloy 740H, was investigated to evaluate its applicability to advanced ultrasupercritical (A-USC) power plants. A series of tensile, creep and fatigue tests were performed at 700°C, and the high temperature mechanical properties of Alloy 740H was compared with those of other candidate materials such as Alloy 617 and Alloy 263. Although the effect of the strain rate on the 0.2% proof stress was negligible, the ultimate tensile strength and the rupture elongation significantly decreased with decreasing strain rate, and the transgranular fracture at higher strain rate changed to intergranular fracture at lower strain rate. The time to creep rupture of Alloy 740H was longer than those of Alloy 617 and Alloy 263. The fatigue limit of Alloy 740H was about half of the ultimate tensile strength. Further, Alloy 740H showed greater fatigue strength than Alloy 617 and Alloy 263, especially at low strain range.
Gas and Steam Turbine Forgings for High Efficiency Fossil Power Plants
Authors: Zeiler Guenter , Putschoegl Albert
Published: March 2024

Sufficient available energy in combination with lowest environmental pollution is a basic necessity for a high standard of living in every country. In order to guarantee power supply for future generations it is necessary to use fossil fuels as efficient as possible. This fact calls for the need of power plants with improved technologies to achieve higher efficiency combined with reduced environmental impact. In order to realize this goal it is not only a challenge for power station manufacturers, but also for manufacturers of special steels and forgings, who have to produce improved components with more advanced materials and more complex manufacturing processes. This paper reports about experiences in the fabrication of forged components for gas and steam turbines followed by achievable mechanical properties and ultrasonic detectability results. The materials are the creep resistant martensitic Cr steels developed in the frame of the European Cost research programme. Whereas Boron containing 10% Cr steels are suitable for steam temperatures of 625°C and slightly higher, Ni-based alloys shall be used for temperatures of 700°C and above. One pilot rotor forging, representing a HP-rotor for welded construction, has been manufactured out of alloy Inconel 625 within the frame of the European Thermie project AD700.
Development and Production of Monoblock Low-Pressure Turbine Rotor Shaft Made from 670 Ton Ingot
Authors: Yamauchi Takafumi , Kudo Hidenao , Kishi Yasuhiro , Ueda Sou , Yoshida Hajime , Kimura Kimitoshi , Kajikawa Koji , Suzuki Shigeru
Published: March 2024

Monoblock low-pressure (LP) turbine rotor shaft forgings for nuclear power plants have been produced from up to 600 ton ingots. However, ingots greater than 600 tons are necessary to increase the generator capacity. Segregation, non-metallic inclusions, and micro porosities inevitably increase with the increase in ingot size. Manufacturing such massive ingots with high soundness is quite difficult. Thus, the development of 650 ton ingot production was carried out in 2010. The 650 ton ingot was dissected and investigated to verify its internal quality. The internal quality of the 650 ton ingot was found to be equal to that of 600 ton ingots. Subsequently, in 2011, we produced a 670 ton ingot, the world’s largest, to produce a trial LP rotor shaft forging with a diameter of 3,200 mm. Results show that the internal quality, mechanical properties, and heat stability are the same as LP rotor shaft forgings made from 600 ton ingots.
High Cycle Fatigue Properties of Steam Turbine Materials at High Temperature Under Superheated Steam Conditions
Authors: Dzugan Jan , Míšek Tomáš , Jurenka Josef
Published: March 2024

Increasing demand for reliable design of all kinds of structures requires materials properties evaluated under the conditions as close to real service conditions as possible. Presently resolved project dealing with development of new turbine blades geometry requires better understanding of the material behavior under service conditions. Service conditions of turbine blades are cyclic loading at high temperatures under superheated steam conditions and complex mechanical loading. There are not commercially available testing systems providing such functionality and thus the system allowing samples testing under considered conditions was developed. The system allows cyclic loading at temperatures up to 650°C under superheated steam conditions. Typical blade steel is investigated here and experimental approach considering complex mechanical loading as well as thermal and corrosion is shown here. The results of high cycle fatigue tests in superheated steam corrosive environment are shown here.
Creep and Creep-Fatigue Crack Growth Behaviors of 30Cr1Mo1V Rotor Steel after Long Term Service
Authors: Shi Kexian , Lin Fusheng , Zhao Shuangqun , Wang Yanfeng
Published: March 2024

This paper presents the creep and creep-fatigue crack growth behaviors of 30Cr1Mo1V turbine rotor steel which had been in service for 16 years. Two typical sections of the rotor, i.e. high and low temperature sections, are examined at 538°C, with crack initiation and propagation monitored by D.C. potential drop method in a compact tension (CT) specimen. The material of the high temperature section has the lower resistance to creep and creep-fatigue crack growths than the low temperature section. The creep crack initiation (CCI) time decreases with the increase of initial stress intensity factor. The creep-fatigue crack growth (CFCG) is dominated by the cycle-dependent fatigue process when the hold time at the maximum load is shorter, but it becomes dominated by the time-dependent creep process when the hold time becomes longer. The high temperature section shows a larger influence of time-dependent creep behavior on CFCG than the low temperature section.
High-Temperature Solid Particle Erosion Testing Standard for Advanced Power Plant Materials and Coatings
Authors: "Swami" Swaminathan V.P. , Smith Jeffery S. , Gandy David W.
Published: March 2024

Solid particle erosion (SPE) harms steam and gas turbines, reducing efficiency and raising costs. The push for ultra-supercritical turbines reignited interest in SPE’s impact on high-temperature alloys. While the gas turbine industry researches methods to improve erosion resistance, a similar need exists for steam turbines. Existing room-temperature SPE test standards are insufficient for evaluating turbine materials. To address this gap, an EPRI program is developing an elevated-temperature SPE standard. This collaborative effort, involving researchers from multiple countries, has yielded a draft standard submitted to ASTM for approval. This presentation will detail the program, test conditions, and the draft standard’s development.
Metrology to Enable High Temperature Erosion Testing – A New European Initiative
Authors: Fry A.T. , Gee M.G. , Clausen S. , Neuschaefer-Rube U. , Bartscher M. , Spaltmann D. , Woydt M. , Radek S. , Cernuschi F. , Nicholls J.R. , Rose T.W.
Published: March 2024

High-temperature solid particle erosion (SPE) is a major threat to efficiency in power plants and jet engines, potentially reducing turbine efficiency by 7-10% and causing significant CO2 emissions. The sources of these particles vary widely, from volcanic ash in engines to fly ash in boilers and scale in turbines. While better surface engineering and coatings offer solutions, their development is hampered by a lack of standardized test methods and reliable models. To address this, the METROSION initiative aims to establish a comprehensive framework for characterizing the high-temperature SPE performance of new materials and coatings. This framework will require a step change in test methods and control, focusing on accurately measuring key parameters like temperature, flow rate, particle properties, and impact angles. This paper outlines the initiative’s goals, with a particular focus on the techniques used for in-situ measurements of temperature, particle velocity, and 3D shape/size.
NiCoCrAlYHf Coating Evolution through Multiple Refurbishment Processing on a Single Crystal Nickel Superalloy
Authors: Rowe A , Karunaratne M , Thomson R C
Published: March 2024

A combination of creep tests, ex-service blade samples, thermodynamic equilibrium calculations, combined thermodynamic and kinetic calculations, image analysis, chemical composition mapping and heat treatments have been conducted on PWA1483 to determine if microstructural rejuvenation can be achieved when taking the presence of oxidation coatings into account as part of a blade refurbishment strategy. The work has shown that the γ′ morphology changes during creep testing, and that through subsequent heat treatments the γ′ microstructure can be altered to achieve a similar γ′ size and distribution to the original creep test starting condition. Thermodynamic equilibrium calculations have been shown to be helpful in determining the optimum temperatures to be used for the refurbishment heat treatments. The interaction of oxidation resistant coatings with the alloy substrate and refurbishment process have been explored with both experimental measurements and coupled thermodynamic and kinetic calculations. The predictive nature of the coupled thermodynamic and kinetic calculations was evaluated against an ex-service blade sample which had undergone refurbishment and further ageing. In general there was good agreement between the experimental observations and model predictions, and the modelling indicated that there were limited differences expected as a result of two different refurbishment methodologies. However, on closer inspection, there were some discrepancies occurring near the interface location between the coating and the base alloy. This comparison with experimental data provided an opportunity to refine the compositional predictions as a result of both processing methodologies and longer term exposure. The improved model has also been used to consider multiple processing cycles on a sample, and to evaluate the coating degradation between component service intervals and the consequences of rejuvenation of the blade with repeated engine exposure. The results from the experimental work and modelling studies potentially offer an assessment tool when considering a component for refurbishment.
Trial Production of Alloy 625 and Alloy 617 Casting Component for Advanced 700°C Class Steam Turbines
Authors: Hirakawa Yuichi , Kadoya Yoshikuni , Nishimoto Shin , Tanaka Yoshinori
Published: March 2024

Advanced Ultra-Super-Critical (A-USC) technology is one of the remarkable technologies being developed to reduce CO2 emissions. The 700°C class A-USC steam turbine project was launched in 2008 to contribute to substantial reductions in CO2 emissions and major Japanese manufacturers of boilers and turbines joined forces with research institutes to bring the project to reality. The use of Ni-base alloys is necessary for high temperature component of 700°C class AUSC steam turbine, and which is required increasing in size of Ni-base casting alloys to apply inner casing, valve body, nozzle block and so on. Therefore, trial production and verification test of Step block (weight: 1.7 ton) with actual component thickness 100-300mm were firstly performed to investigate basic casting material properties in this study. As candidate alloy, alloy 617 was chosen from a commercially available Ni-base alloy, from the viewpoint of large component castability and balance of mechanical properties stability at 700°C use. Microstructure test, high temperature mechanical test and long-term heating test of each thickness part specimen were carried out and good creep rupture strength was obtained. Next, the nozzle block of alloy 617 was manufactured for the trial casting of the actual machine mock-up component with complex shape (weight: 1.2 ton). For a comparison, alloy 625 was cast at the same time. Both castings of alloy 617 and alloy 625 were able to manufacture without a remarkable defect. Detailed comparisons to microstructures and mechanical properties are included in this paper.
Material Behavior of T23 and T24
Authors: Siefert John A. , DuPont John N.
Published: March 2024

The use of the bainitic class of creep strength enhanced ferritic steels T/P23 and T24 has increased over the last decade in a wide range of applications including replacement headers, superheater and reheater tubing and in waterwall tubing. Many issues have been reported in one or both of these materials including hydrogen induced cracking, reheat cracking and stress corrosion cracking. To appropriately address these issues, work has been initiated that includes a literature review, development of a database of phase transformation temperatures, investigation of tempering behavior, and an analysis of the effect of phase transformation on residual stresses. Such information will be provided in the context of understanding why these two materials appear highly susceptible to these cracking mechanisms.
Phase Transformations and Microstructure in Gas Tungsten Arc Welds of Grade 23 Steel Tubing
Authors: Alexandrov B.T. , Steiner J.M. , Strader K.C. , Feng X. , Lippold J.C. , Dierksheide J.E. , Tanzosh J.M.
Published: March 2024

The objective of this study was to determine the typical range of weld metal cooling rates and phase transformations during multipass gas-tungsten arc (GTA) welding of Grade 23 (SA-213 T23) tubing, and to correlate these to the microstructure and hardness in the weld metal and heat affected zone (HAZ). The effect of microstructure and hardness on the potential susceptibility to cracking was evaluated. Multipass GTA girth welds in Grade 23 tubes with outside diameter of 2 in. and wall thicknesses of 0.185 in. and 0.331 in. were produced using Grade 23 filler wire and welding heat input between 18.5 and 38 kJ/in. The weld metal cooling histories were acquired by plunging type C thermocouples in the weld pool. The weld metal phase transformations were determined with the technique for single sensor differential thermal analysis (SS DTA). The microstructure in the as-welded and re-heated weld passes was characterized using light optical microscopy and hardness mapping. Microstructures with hardness between 416 and 350 HV0.1 were found in the thick wall welds, which indicated potential susceptibility to hydrogen induced cracking (HIC) caused by hydrogen absorption during welding and to stress corrosion cracking (SSC) during acid cleaning and service.
Heat-to-Heat Variation in Creep Rupture Ductility of ASME Gr.91 Steels in the Long-Term-Investigation into Recovery of Microstructure and Void Formation
Authors: Kobayashi Satoru , Sawada Kota , Hara Toru , Kushima Hideaki , Kimura Kazuhiro
Published: March 2024

Recovery of microstructure and void formation were investigated in creep-ruptured specimens of ASME Gr. T91 steels to understand the cause of loss of creep rupture ductility in the long-term creep condition and its heat-to-heat variation. The specimens studied were two heats (MGA, MGC) of Gr. T91 steels creep-ruptured at 600 °C under the stress conditions of 160-80 MPa. The reduction of area at rupture (RA) was 55% for MGA, but 83% for MGC in the long-term condition (under the creep stress of 80 MPa), while RA was higher than 80 % for the two heats in the short-term conditions (under the creep stresses above 100 MPa). In both heats, equiaxed grains were observed in the vicinity of ruptured surface in the long-term condition, indicating that recovery and recrystallization occurred extensively in the creep condition, while grains were elongated in the short-term conditions. In the uniformly deformed regions with a small area reduction in the long-term crept specimens, recovered and recrystallized grains were observed in the limited region close to high angle grain boundaries in MGA, while they were extended into grain interiors in MGC. In the long-term creep conditions two types of voids were observed: fine ones with a diameter below 1 μm and coarse ones with a diameter from 2 μm up to 50 μm. Fine creep voids were found to grow with necking in MGA while they neither nucleated nor grew with necking in MGC. Coarse creep voids increased in size and in number with necking in both heats and were larger and denser in MGA than in MGC.
Experiences in the Production and Welding of 9-12 % Cr Steels Explained on Grades 92 and VM12-SHC for USC Power Plants
Authors: Knezevic Vida , Subanovic Marko , Hamart Olivier , Heuser H. , Tak K.G.
Published: March 2024

This paper addresses the limitations of P92 steel used in ultra-supercritical power plants, particularly ferrite formation in thick components and its impact on short- and long-term properties. A guideline for determining ferritic content in P92 steel is presented. Furthermore, a novel 12% Cr boiler steel grade, VM12-SHC, is introduced. This new material offers good creep properties and oxidation resistance, overcoming the limitations of P92 steel. Finally, the development of matching filler metals for welding P92 and VM12-SHC steels is presented, ensuring optimal weld compatibility and performance in power plant applications.
Creep-Fatigue Interaction in Grade 92 Steel and Its Predictability
Authors: Takahashi Yukio , Parker Jonathan , Gandy David
Published: March 2024

Creep rupture strength is the principal material property prioritized in designing power generation plants against the steady-state stress due to internal pressure. Increasingly plants must cycle so there is a possibility of life reduction due to creep-fatigue interaction. Grade 92 steel is one of the creep strength enhanced ferritic (CSEF) steels which has superior creep strength compared to other CSEFs. It is expected to be widely used in coal-fired ultra-super critical plants as well as in LNG-fired combined cycle plants. However, at present there is insufficient information regarding the creep-fatigue behavior of this material. A joint study has been conducted to understand the behavior of this steel under creep-fatigue condition and see how accurate the failure life can be estimated. Three kinds of base materials as well as two kinds of welded joints have been tested under strain-controlled cyclic loading with or without hold times as well as under constant load creep condition. Continued decrease in the number of cycles to failure was observed with the extension of hold time in all the base metals and cross-weld specimens. It was found that the modified ductility exhaustion approach based on inelastic strain, as well as its extension employing the inelastic strain energy density, made reasonably accurate predictions of failure lives under a wide range of test conditions. Temperature- and rate-dependencies of fracture limits in terms of inelastic strain and energy density were able to be uniquely expressed using simple thermal activation energy parameters.
Evaluation of Long-Term Creep Rupture Life of Strength Enhanced High Cr Ferritic Steel on the Basis of Its Temperature Dependence
Authors: Maruyama K. , Nakamura J. , Yoshimi K.
Published: March 2024

Conventional time-temperature-parameter (TTP) methods often overestimate long-term creep rupture life of creep strength enhanced high Cr ferritic steels. The cause of the overestimation is studied on the basis of creep rupture data analysis on Gr.91, 92 and 122 steels. There are four regions with different values of stress exponent n for creep rupture life commonly in stress-rupture data of the three ferritic steels. Activation energies Q for rupture life in the regions take at least three different values. The values of n and Q decrease in a longer-term region. The decrease in Q value is the cause of the overestimation of long-term rupture life predicted by the conventional TTP methods neglecting the change in Q value. Therefore, before applying a TTP method creep rupture data should be divided into several data sets so that Q value is unique in each divided data set. When this multi-region analysis is adopted, all the data points of the steels can be described accurately, and their long-term creep life can be evaluated correctly. Substantial heat-to-heat and grade-to-grade variation in their creep strength is suggested under recent service conditions of USC power boilers.
Evaluation of Supercritical Oxidation Resistance of Boiler Tube Materials
Authors: Yli-Olli Sanni , Tuurna Satu , Penttilä Sami , Auerkari Pertti , Zabetta Edgardo Coda , Vänskä Kyösti
Published: March 2024

To improve the efficiency of fossil fuel power plants the operating temperatures and pressures need to be increased. However, at high temperatures the steam side oxidation resistance becomes a critical issue for the steels used especially at the final stages of superheaters and reheaters. Apart from the chemical composition of the material, surface condition is a major factor affecting the oxidation resistance in steam and supercritical water. In this paper, stainless boiler steels (UNS S34710, S31035, S31042, and S30942) are investigated for oxidation resistance in flowing supercritical water. Tests were conducted in an autoclave environment (250 bar, with 125 ppb dissolved oxygen and a pH of 7) at 625°C, 650°C and 675°C for up to 1000 h. Materials were tested with as-delivered, shot peened, milled or spark eroded and ground surface finish. The results show a strong influence of surface finish at the early stages of oxidation. Oxides formed on cold worked surfaces were more adherent and much thinner than on a spark eroded and ground surface. This effect was stronger than the influence of temperature or alloy composition within the tested ranges.
Steam Loop Testing of A-USC Materials for Oxidation and Fireside Corrosion - Alstom’s Experience to Date
Authors: Ganta Reddy , Marion John , Wilhelm Bruce , Pschirer Jim , Goodstine Steve , Boohaker Charles
Published: March 2024

Nickel-based alloys and stainless steel Super304H, along with various coatings, are undergoing testing in a steam loop at Alabama Power’s Plant Barry. These materials are being evaluated for use in advanced ultra-supercritical (A-USC) fossil-fired power plants at temperatures ranging from 538°C to 815°C. The loop has been operational for over 18 months, with the alloys exceeding 6,300 hours above 538°C. An additional 7,000 hours at high temperatures are planned before the loop’s removal in 2014. Initial inspections show minimal material corrosion, suggesting their suitability for A-USC applications. This paper details the loop’s design, materials, manufacturing, operation, and inspection findings. Additionally, it describes a methodology for predicting steam-side oxidation and fireside corrosion rates and highlights the significance of this testing for A-USC development and commercialization.
Effect of Alloy Composition on Fireside Corrosion Rates in Air- and Oxy-Fired Systems
Authors: Pint B.A.
Published: March 2024

Using oxygen, rather than air, in coal-fired boilers has been studied for several years as a strategy to reduce NOx and concentrate CO2 for capture. In combination with flue gas recirculation, higher levels of CO2 are expected but increased H2O and SO2 levels also may occur. In order to understand the role of substrate composition on corrosion, a combination of commercial and model alloys were investigated with synthetic coal ash and gas compositions simulating air- and oxyfiring environments. Exposure temperatures ranged from 600°-800°C to cover current operating temperatures up to advanced ultrasupercritical conditions. Using 500h exposures, no consistent negative effect was found for switching to the oxy-firing environment with the same synthetic ash. For model Fe-Cr alloys, 30%Cr was needed to form a thin protective reaction product across this temperature range. Among the commercial stainless steels, 310-type stainless steel showed low reaction rates with the maximum attack at 650°C. At higher temperatures, the depth of attack on Fe-base type 310 stainless steel was less than for Ni-base alloy 740. Initially, this difference was attributed to the Al and Ti additions in alloy 740. However, cast and hot rolled model Ni-18Cr and -22Cr alloys with various Al and Ti additions showed decreased metal loss with increasing Al and Ti additions in the oxy-firing environment at 700° and 800°C. As expected, metal loss was very sensitive to Cr content. A second set of model alloys also examined the effect of Co and Mo.
Study of Creep Damage in Creep Exposed Martensitic High-Chromium Steel Weldments
Authors: Schlacher C. , Béal C. , Sommitsch C. , Toda H. , Mayr P.
Published: March 2024

Boron and nitride additions are emerging as a promising design concept for stabilizing the microstructure of creep-resistant martensitic high-chromium steels. This approach, known as MarBN steel (martensitic steel strengthened by boron and nitrogen), combines the benefits of solid solution strengthening from boron with precipitation strengthening from nitrides. However, initial welding trials revealed challenges in achieving a uniform fine-grained region in the heat-affected zone (HAZ), which is crucial for mitigating Type IV cracking and ensuring creep strength. Despite these initial hurdles, preliminary creep test results for welded joints have been encouraging. This study presents an improved MarBN steel formulation and its investigation through uniaxial creep tests. Base material and welded joints were subjected to creep tests at 650°C for up to 25,000 hours under varying stress levels. The analysis focused not only on the creep strength of both the base material and welded joints but also on the evolution of damage. Advanced techniques like synchrotron micro-tomography and electron backscatter diffraction were employed to understand the underlying creep damage mechanisms. By combining long-term creep testing data with 3D damage investigation using synchrotron micro-tomography, this work offers a novel perspective on the fundamental failure mechanisms occurring at elevated temperatures within the HAZ of welded joints in these advanced steels.