bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Inconel 740H to Pipe Transition Joints in Advanced Power Plant
Authors: Moody P. , Barnard P. , Dauda T. , Baker B.A. , Gollihue R.D.
Published: March 2024

INCONEL 740H has been developed by Special Metals for use in Advanced Ultra Super Critical (A-USC) coal fired boilers. Its creep strength performance is currently amongst the ‘best in class’ of nickel based alloys, to meet the challenge of operating in typical A-USC steam temperatures of 700°C at 35 MPa pressure. Whilst the prime physical property of interest for INCONEL 740H has been creep strength, it exhibits other physical properties worthy of consideration in other applications. It has a thermal expansion co-efficient that lies between typical values for Creep Strength Enhanced Ferritic (CSEF) steels and austenitic stainless steels. This paper describes the validation work in support of the fabrication of a pipe transition joint that uses INCONEL 740H pipe, produced in accordance with ASME Boiler Code Case 2702, as a transition material to join P92 pipe to a 316H stainless steel header. The paper gives details of the material selection process, joint design and the verification process used for the joint.
Precipitate Phase Stability and Compositional Dependence on Alloying Additions in Advanced Ni-Base Superalloys
Authors: Antonov S. , Detrois M. , Tin S.
Published: March 2024

Modern polycrystalline Ni-base superalloys for advanced gas turbine engines have been a key component that has contributed to technological advances in propulsion and power generation. As advanced turbine engine designs are beginning to necessitate the use of materials with temperature and strength capabilities beyond those exhibited by existing materials, new alloying concepts are required to replace conventional Ni-base superalloys with conventional γ-γ’ microstructures. The phase stability of various high Nb content Ni-base superalloys exhibiting γ-γ’-δ -η microstructures have been the subject of a number of recent investigations due to their promising physical and mechanical properties at elevated temperatures. Although high overall alloying levels of Nb, Ta and Ti are desirable for promoting high temperature strength in γ-γ’ Ni-base superalloys, excessive levels of these elements induce the formation of δ and η phases. The morphology, formation, and composition of precipitate phases in a number of experimental alloys spanning a broad range of compositions were explored to devise compositional relationships that can be used to predict the microstructural phase stability and facilitate the design of Ni-base superalloys.
Development of Ni-Base Superalloy USC141 for 700°C Class A-USC Boiler Tubes
Authors: Uehara Toshihiro , Sato Naoya , Shimizu Masaru , Schraven Patrik
Published: March 2024

Recently, a γ’ precipitation strengthened Ni-base superalloy, USC141, was developed for 700°C class A-USC boiler tubes as well as turbine blades. In boiler tube application, the creep rupture strength of USC141 was much higher than that of Alloy617, and the 105 hours’ creep rupture strength of USC141 was estimated to be about 180MPa at 700°C. This is because fine γ’ particles precipitate in austenite grains and some kinds of intermetallic compounds and carbides precipitate along austenite grain boundaries during creep tests. Good coal ash corrosion resistance is also required for tubes at around 700°C. It is known that coal ash corrosion resistance depends on the contents of Cr and Mo in Ni-base superalloys. Therefore the effect of Cr and Mo contents in USC141 on coal ash corrosion resistance, tensile properties, and creep rupture strengths were investigated. As a result, the modified USC141 containing not less than 23% Cr and not more than 7% Mo showed better hot corrosion resistance than the original USC141. This modified alloy also showed almost the same mechanical properties as the original one. Furthermore the trial production of the modified USC141 tubes is now in progress.
Power Austenite- A Novel σ-Phase Hardened High Temperature Alloy for 700 °C (1292 °F) Fired Boilers
Authors: Spiegel Michael , Schraven Patrik
Published: March 2024

The article gives a brief overview of the newly developed austenitic material “Power Austenite”. The microstructure of the Power Austenite is characterized by grain boundary strengthening with boron stabilized M23(C,B)6 and secondary Nb(C,N) in combination with sigma phase and Nb(C,N) as the major grain strengthening precipitates. The material shows a significant creep strength at 700 °C (1292 °F) and 650 °C (1202 °F) as well as fireside corrosion resistance which makes it a possible candidate for 700 °C (1292 °F) power plants.
Creep Behavior and Microstructural Evolution of Super 304H
Authors: Sanders Paul G. , White Calvin L. , Seguin Daniel J. , Raju Kada Sitarama , Shingledecker John P.
Published: March 2024

Long-term creep tested specimens of the advanced austenitic stainless steel Super 304H were subjected to detailed metallographic analysis with an emphasis on the relationship between creep induced cavities (voids) and microstructural features. The creep specimens were tested between 873 and 973 K (600 and 700°C) at stresses between 110 and 340 MPa, with rupture times up to ~1.8 x 108 s (50,000 hours). To characterize damage, the distributions of creep cavities along the length of the gage section were determined and microstructural features associated with the cavities were investigated using optical microscopy and scanning electron microscopy.
Steelmaking Challenges to Achieve Grade 91 with Ultra-Low Impurity Content
Authors: Mariani P. , Marinari A. , Donati M. , Arrigoni M.
Published: March 2024

Grade 91 steel has achieved broad acceptance within the modern boiler industry to fabricate a variety of critical pressure components including tubing, piping and headers, particularly in Ultra Super Critical (USC), Advanced Ultra Super Critical (A-USC) and Combined Cycle Power Plants (CCPP). The applications for which this material is used enforce severe requirements on strength, corrosion, creep properties and thermal stability during service. The properties of Creep Strength Enhanced Ferritic steels (CSEF) such as Grade 91 are critically dependent on manufacturing factors like steelmaking, heat treatments and welding: poor control of these parameters can severely compromise material properties. In scientific literature, several studies correlate low creep ductility to high content of trace elements such As, Sn, Sb, Pb, Cu, P and S. Since the current reference Codes, namely ASTM/ASME, don’t require particular restrictions for these elements, Electric Power Research Institute (EPRI) has issued guidelines for grade 91 which enforce a significant reduction of impurities and trace elements. This paper discusses steelmaking operating challenges to produce Grade 91 steel with very low contents of the above mentioned residual elements, starting from the furnaces charges, up to the chemical composition measuring equipment used in the steel shop laboratories.
Effect of Ductility on Load-Stress Conversion Factor of Small Punch Creep Test
Authors: Komazaki Shin-ichi , Ohkawa Yuya , Yonemura Mitsuharu
Published: March 2024

Remaining-life assessment of high temperature components using the small punch (SP) creep testing technique necessitates the evaluation of SP load (F)/uniaxial stress (σ) conversion factor, F/σ, obtained by comparing the SP and uniaxial creep test results. In the present study, the SP creep tests were carried out at 850°C on various Ni-base alloys having different reduction of area in the range of 0.05-0.67 to investigate the influence of creep ductility on the value of F/σ. The F/σ value was determined for each alloy by correlating SP creep rupture data with corresponding uniaxial creep ones. The experimental results revealed that the F/σ value was not well correlated with Vickers hardness, but it increased almost linearly with increasing reduction of area up to around 0.4. This result indicated that the SP creep rupture data could be converted to the uniaxial data if the creep ductility on a given material was available.
Development of Low Thermal Expansion Fe-Ni-Cr Austenitic Heat Resistant Steel for High Temperature Steam Turbine
Authors: Oinuma Shun , Takaku Reki , Nakatani Yujiro , Imai Kiyoshi , Yamada Masayuki , Kubo Takahiro
Published: March 2024

Austenitic heat resistant steels are one of the most promising materials to be applied around 650°C, due to its superior creep strength than conventional ferritic steels and lower material cost than Ni based superalloys. The problem of austenitic steels is its high thermal expansion coefficient (CTE), which leads to high deformation and stress when applied in rotors, casings, blades and bolts. To develop low CTE austenitic steels together with high temperature strength, we chose the gamma-prime strengthened austenitic steel, A-286, as the base composition, and decreased the CTE by introducing the invar effect. The developed alloy, Fe-40Ni-6Cr-Mo-V-Ti-Al-C-B, showed low CTE comparable to conventional ferritic steels. This is mainly due to its high Ni and low Cr composition, which the invar effect is prone even at high temperature region. This alloy showed higher yield strength, higher creep rupture strength and better oxidation resistance than conventional high Cr ferritic steels and austenitic steels. The 2 ton ESR ingot was forged or hot rolled without defects, and the blade trial manufacturing was successfully done. This alloy is one of the best candidates for USC and A-USC turbine components.
The Influence of Surface Quality of Grade 91 Tubing on Long-Term Oxidation in Steam
Authors: Gorman David M. , Fry Antony T.
Published: March 2024

Oxide scale formation in the inner bore of steam tubing has been identified as a key metric for determining operational parameters and life expectancy of modern boiler systems. Grade 91 tubing is commonly used for the construction of key components within boiler systems designed for power generation operating in the temperature range of 500 to 650 °C. Standard laboratory test procedures involve grinding the surface of test coupons to homogenise their surface structure and improve experimental consistency, however, data presented here shows a discrepancy between laboratory and industrial practices that has long term implications on scale growth kinetics and morphological development. Microstructural analysis of both virgin and ex-service tubing reveals the presence of a pre-existing oxide structure that is incorporated into the inwardly growing scale and is implicated in the formation of multiple laminar void networks. These void networks influence thermal diffusivity across the scale and may function as regions of spallation initiation and propagation.
Property of 9Cr-3W-3Co-Nd-B Heat-Resistant Steel SAVE12AD Welded Joint
Authors: Kurihara Shinnosuke , Osuki Takahiro , Hamaguchi Tomoaki , Semba Hiroyuki , Okada Hirokazu , Hirata Hiroyuki , Yoshizawa Mitsuru
Published: March 2024

Developed 9Cr-3W-3Co-Nd-B heat-resistant steel SAVE12AD (Recently designated as ASME Grade 93) pipes and tubes have higher creep strength in both base metal and welded joints than conventional high Cr ferritic steels such as ASME Grades 91, 92 and 122. The welded joints of SAVE12AD tubes with commercial filler wire for W62-10CMWV-Co (Gr. 92) or Ni base filler wire ERNiCr-3 (Alloy82) also have much better creep rupture strength than those of conventional steels because of suppression of refining in the Heat-Affected-Zone (HAZ). However, the creep rupture strength of weld metal of W62-10CMWV-Co was marginal. Additionally, the hot cracking susceptibility of weld metal using Ni base filler wire ERNiCr-3 was occasionally below the required level. Similar welding consumable for SAVE12AD has been developed to solve these problems. Optimization of nickel, neodymium and boron contents on similar welding consumable enables to obtain both the good long-term creep rupture strength and low enough hot cracking susceptibility of weld metal. Consequently, SAVE12AD welded joint is expected to be applied of piping and tubing above 600°C in USC power plants because of its good properties with similar welding consumable.
Long-Term Material Tests in Liquid Molten Salts
Authors: Preußner J. , Pfeiffer W. , Piedra E. , Oeser S. , Tandler M. , von Hartrott P. , Maier G.
Published: March 2024

Solar salts are used as an energy storage media and heat transfer fluid in power plants. The salts can cause significant corrosion to various steels that are in contact with the salt. Static corrosion tests performed with different steels show, that the corrosive attack by industrial grade salt melts is more severe than by defined grade salt melts and the sample corrosion is faster (i.e. the weight gain is larger) for higher temperatures. Slow strain rate (SSR) tests in salt are difficult to conduct due to the corrosive attack of the salt also on the test setup. The SSRT setup in salt could be realized and tests could be conducted successfully. No clear evidence for an accelerated failure of samples tested in salt compared to samples tested in air could be found on Alloy 347 Nb. Comparative low cycle fatigue (LCF) tests at air and in molten salt atmosphere were successfully performed and showed similar results on tubes out of Sanicro 25. No evidence of accelerated crack growth in molten salt could be found.
Long-Term Creep Rupture Strength and Microstructural Evolution of Weldments in Mod.9Cr-1Mo Steels
Authors: Arisue Ko , Komai Nobuyoshi , Tominaga Kimihiko , Fujita Masaaki
Published: March 2024

Large heat-to-heat variation of creep rupture strength in weldments of mod.9Cr-1Mo steels was observed in the creep rupture tests conducted for two different heats at 600°C and 650°C. One heat showed consistently lower time-to-rupture than the other for 130-60MPa at 600°C. Detailed microstructural investigations revealed that the number density of precipitates in the weaker heat was remarkably lower than that associated with the stronger heat through most of the creep region. Accordingly, heat-to-heat variation of creep rupture strength was attributed to the difference in the precipitate strengthening effects throughout creep. Equilibrium calculation predicted that the smaller phase fraction of M23C6 and VN precipitates due to the lower content of chromium and lower ratio of nitrogen/aluminum in the weaker heat. However, given that long-term creep rupture strength at 650°C converged for the two heats, the microstructure including precipitates may settle into a similar level for subsequent longer hours even at 600°C.
Influence of Fusion Ratio on Carbon Migration Phenomenon in the Narrow Gap Welding of Dissimilar Metals in 9% Chromium Steels
Authors: Ding Yuming , Xu Xiaojin , Zheng Yunwei , Cai Zhipeng , Pan Jiluan
Published: March 2024

Carbon migration in narrow-gap welding joints of dissimilar steels has been studied using bead-on-plate specimens to determine the factors that influence the formation of a soft ferrite structure in the carbon-depleted zone. Carbon migration was found to occur during tempering, with a ferrite structure formed at the intersection of multiple layers due to severe carbon migration. This was attributed to a steep gradient in Cr content caused by the low fusion penetration at the intersection. Experimental results and the relationship between fusion penetration and weld bead alignment confirmed that low fusion penetration is the main cause of ferrite-structured carbon depleted zones.
History of Allowable Stresses in Japan and Perspective on Improvement in Creep Strength Property of Grade 91 Steel
Authors: Kimura Kazuhiro , Sawada Kota
Published: March 2024

Creep strength of Grade 91 steels has been reviewed and allowable stress of the steels has been revised several times. Allowable stress regulated in ASME Boiler and Pressure Vessel Code of the steels with thickness of 3 inches and above was reduced in 1993, based on the re-evaluation with long-term creep rupture data collected from around the world. After steam leakage from long seam weld of hot reheat pipe made from Grade 122 steel in 2004, creep rupture strength of the creep strength enhanced ferritic (CSEF) steels has been reviewed by means of region splitting method in consideration of 50% of 0.2% offset yield stress (half yield) at the temperature, in the committee sponsored by the Ministry of Economy, Trade and Industry (METI) of Japanese Government. Allowable stresses in the Japanese technical standard of Grade 91 steels have been reduced in 2007 according to the above review. In 2010, additional long-term creep rupture data of the CSEF steels has been collected and the re-evaluation of creep rupture strength of the steels has been conducted by the committee supported by the Federation of Electric Power Companies of Japan, and reduction of allowable stress has been repeated in 2014. Regardless of the previous revision, additional reduction of the allowable stress of Grade 91 steels has been proposed by the review conducted in 2015 by the same committee as 2010. Further reduction of creep rupture strength of Grade 91 steels has been caused mainly by the additional creep rupture data of the low strength materials. A remaining of segregation of alloying elements has been revealed as one of the causes of lowered creep rupture strength. Improvement in creep strength may be expected by reducing segregation, since diffusional phenomena at the elevated temperatures is promoted by concentration gradient due to segregation which increases driving force of diffusion. It has been expected, consequently, that the creep strength and allowable stress of Grade 91 steels can be increased by proper process of fabrication to obtain a homogenized material free from undue segregation.
Influence of Manufacturing Process Parameters on 9-12% Cr Ferritic Steel Performance
Authors: Gligor A. P. , Ferrara A. , Ortolani M.
Published: March 2024

Modified 9Cr-1Mo alloy steel has been developed over the last few decades and has since gained wide acceptance in the boiler industry for the production of a variety of pressure-critical components, including tubing, piping and headers. The properties of creep-strength enhanced ferritic steels such as grade 91 are critically dependent on manufacturing parameters such as steelmaking, hot deformation, heat treatment and welding. Since the applications for which this material is used impose strict requirements in terms of resistance, corrosion, and creep behavior, poor process control can severely compromise the service behavior. This work discusses the impact of total deformation during the rolling process, and heat treatment parameters on time-independent and time-dependent properties for grade 91. For this study, two heats with similar chemical composition were produced with different reduction ratios: to which, several normalizing and tempering combinations were applied. For each combination, the microstructure was characterized, including evaluation of segregation by metallographic examination, and analysis of secondary phase precipitates by means of X-ray powder diffraction. Mechanical testing and creep testing were performed. A comparison of results is presented, and recommendations on the optimal process parameters are provided to ensure reliable performance of grade 91 material.
Metallurgical Risk Factors in Grade 91 Steel
Authors: Jabar Sharhid , West Geoff D , Shollock Barbara , Siefert John
Published: March 2024

Modified 9Cr-1Mo steel (ASTM Gr.91) is widely used in components of fossil fueled power plants around the world today. This grade of steel has however been shown to exhibit significant variations in creep life and creep ductility, which has led to premature in-service failures. The aim of this work is to define potential metallurgical risk factors that lead to this variation in performance. To achieve this, a set of creep test samples that represent a wide range in this variation of creep behavior in this steel grade have been studied in detail. As a first stage in this characterization the macro-scale chemical homogeneity of the materials were mapped using micro-XRF. Understanding the segregation behavior also allows quantification of microstructural parameters in both segregated and non-segregated areas enabling the variations to be determined. For example this showed a significant increase in the number per unit area of Laves phase particles in high compared with low Mo content areas. To study the effect of MX particles on segregation a methodology combining SEM and TEM was employed. This involved chemically mapping the larger V containing particles using EDS in the SEM in segregated and unsegregated areas and then comparing the results to site-specific TEM analysis. This analysis showed that although the average size of the V containing samples is in the expected 0-50 nm size range, these particles in some samples had a wide size distribution range, which significantly overlaps with the M23C6 size distribution range. This together with the segregation characteristics has important implications for determining meaningful quantitative microstructural data from these microstructurally complex materials.
Creep-Fatigue Interactions in 9CR Martensitic Cast Steel—Microstructure and Mechanical Behavior
Authors: Speicher Magdalena , Jobski Dirk , Kontermann Christian
Published: March 2024

This study presents a characterization of the microstructural evolutions taking place in a 9%Cr martensitic cast steel subjected to fatigue and creep-fatigue loading. Basis for this study of investigation is an extensive testing program performed on a sample heat of this type of steel by conducting a series of service-like high temperature creep-fatigue tests. The major goal here was to systematically vary specific effects in order to isolate and describe relevant damage contributing mechanisms. Furthermore, some of the tests have been interrupted at several percentages of damage to investigate not only the final microstructure but also their evolution. After performing those tests, the samples were examined using transmission electron microscopy (TEM) to characterize and quantify the microstructural evolutions. The size distribution of subgrains and the dislocation density were determined by using thin metal foils in TEM. A recovery process consisting of the coarsening of the subgrains and a decrease of the dislocation density was observed in different form. This coarsening is heterogeneous and depends on the applied temperature, strain amplitude and hold time. These microstructural observations are consistent with the very fast deterioration of creep properties due to cyclic loading.
Effect of Boron Nitrides and Aluminum Nitrides on Long-Term Creep Life and Rupture Ductility of Martensitic 9 to 12Cr Steels
Authors: Abe Fujio , Ohba Toshio , Miyazaki Hideko , Toda Yoshiaki , Tabuchi Masaaki
Published: March 2024

The effect of boron nitrides (BN) and aluminum nitrides (AlN) on long-term creep life and rupture ductility has been investigated for martensitic 9 to 12Cr steels at 550 to 700 °C. The BN particles form in 9 to 12Cr steels during normalizing heat treatment at 1050 to 1150 °C, suggesting no change in the amount of BN particles during creep. On the other hand, the AlN particles gradually form during creep at 550 to 700 °C, decreasing the concentration of nitrogen free from the AlN particles. The degradation in creep life takes place more significantly with test duration in the steels containing high Al but not in those containing the BN particles. The rupture ductility is evaluated by using a semi-logarithmic diagram of the RA and total elongation, showing the necking dominant and void swelling dominant regions. The BN and AlN particles are responsible for the degradation in RA at low stresses and long times by accelerating the formation of creep voids at interfaces between the BN and AlN particles and alloy matrix.
Microstructure Evolution during Isothermal Aging of Multimodal Ni-Based Superalloys
Authors: Yamaguchi Yoshiya , Tajima Ryotaro , Terada Yoshihiro
Published: March 2024

The morphological evolution of secondary γ′ precipitates under the coarsening process was investigated for commercial wrought Ni-based superalloys, which can be classified into two processes, i.e. “localization process” and “aggregation process”. The localization process was defined as a phenomenon in which cuboidal γ′ precipitates were arranged in the <100> direction for superalloys. In contrast, the aggregation process was defined as a phenomenon in which neighboring spherical γ′ precipitates coarsen while overlapping their interfaces for superalloys. All the wrought Ni-based superalloys could be classified into the above two processes based on their volume fraction and lattice misfit. The coarsening of γ′ precipitates follow the aggregation process when the misfit is smaller than 0.05%, and it follows the localization process otherwise.
Advanced Ultra-Supercritical Valve Development Program
Authors: Khelfaoui Fadila , Vernhes Luc , Isbitsky Stanley , Rene Rejean , Schmitt Julien , Schmitt Thomas
Published: March 2024

Materials are the key to develop advanced ultra-supercritical (A-USC) steam generators. Operating at temperature up to 760°C and sustained pressure up to 4500 psi. Pressure vessel and piping materials may fail due to creep, oxidation, and erosion. Valves are particularly subjected to loss of function and leakage due to impermeant of the sealing surfaces. New materials, less susceptible to the above damage modes are needed for A-USC technology. Two Ni-based superalloys have been identified as prime candidates for valves based materials. Hardfacing is applied to sealing surfaces to protect them from wear and to reduce friction. Stellite 6 (Cobalt-based alloy) is the benchmark hardfacing owing to its anti-galling properties. However, the latest results tend to indicate that it is not suitable for high pressure application above 700°C. An alternative hardfacing will be required for A-USC. New Ni- and Co- based alloys are being developed for applications where extreme wear is combined with high temperatures and corrosive media. Their chemistry accounts for the excellent dry-running properties of these alloys and makes them very suitable for use in adhesive (metal-to- metal) wear. These new alloys have better wear, erosion, and corrosion resistance than Stellite 6 in the temperature range 800°C ~ 1000°C. As such, they have the potential to operate in A-USC. Velan recently developed an instrumented high temperature tribometer in collaboration with Polytechnique Montreal to characterize new alloys including static and dynamic coefficients of friction up to 800°C. We present herein the methodology that has been devolved to explore the effects of elevated temperature on the tribological behavior of those advanced material systems, with the goal of capturing the basis for the specification, design, fabrication, operation, and maintenance of valves for A-USC steam power plants.
Phase-Field Simulation and Machine Learning for Predicting Rafting Kinetics in Ni-Based Superalloys
Authors: Matsuoka Yusuke , Tsukada Yuhki , Koyama Toshiyuki
Published: March 2024

Directional coarsening of the γ' phase (rafting) in Ni-based single crystal superalloys during creep at 1273 K was simulated by the phase-field method. The inelastic strain introduced in the γ phase was assumed to be composed of plastic strain (εp) and creep strain (εc). The simulations were performed with various sets of values of material parameters and the magnitude of external tensile stress. We let a feed-forward neural network learn the simulation data in order to enable fast and exhaustive prediction of the time to rafting, traft. From the analysis based on the trained neural network, it has been shown that traft becomes longer with increasing magnitude of γ/γ' lattice misfit, with decreasing creep coefficient, and with increasing yield stress of the γ phase (σγys). The sensitivity of traft to σγys is high when the ratio of εp to the total inelastic strain (εp + εc) is high.
Microstructure and Mechanical Properties of Haynes 282 Fabricated by Electron Beam Melting
Authors: Dryepondt Sebastien , Kirka Mike M. , Fernandez-Zelaia Patxi , Unocic Kinga A.
Published: March 2024

The Haynes 282 Ni-based superalloy (57Ni-20Cr-10Co-8.5Mo-2.1Ti-1.5Al) is a very promising candidate for the fabrication by additive manufacturing of gas turbine components of complex geometries. Alloy 282 was fabricated by electron beam melting (EBM) and exposed to two different heat treatments, (a) solution anneal (SA) at 1135°C followed by the standard 2-step aging treatment (2h at 1010°C plus 8h at 788°C) and (b) SA followed by 4h 800°C. Large elongated grains were observed for the as-fabricated and annealed EBM 282 materials, with a γ′ (Ni3(Al,Ti)) average size of ~100 nm and 20 nm, respectively. The as-fabricated EBM 282 alloy exhibited good ductility at 20-900°C and tensile strength slightly lower than the tensile strength of wrought 282. Annealing the alloy resulted in a moderate increase of the alloy strength at 800 and 900°C but a decrease of the alloy ductility. The creep lifetime at 800°C, 200MPa of the as-fabricated and annealed EBM 282 specimens machined along the build direction was 2 times and 1.5 times superior to the expected lifetime for wrought 282, respectively. For creep specimens machined perpendicular to the build direction, the lifetimes were ~25% lower compared to the wrought alloy. These creep results are directly related to the strong grain texture of the EBM 282 alloy and the limited impact of the initial γ′ (Ni3(Al,Ti)) size on alloy 282 creep properties.
A Unique Influence of Creep Deformation on the Subsequent Fatigue Crack Propagation in a Single Crystal Ni-Base Superalloy
Authors: Suzuki Shiyu , Sakaguchi Motoki , Inoue Hirotsugu
Published: March 2024

Single crystal Ni-base superalloys are subjected to tension hold at high temperature in addition to cyclic loading during the operation of gas turbines. Various studies have investigated creep-fatigue crack propagation in superalloys under trapezoidal loadings and evaluated the life time based on parameters such as creep J-integral. However, it is still unclear how damage field and stress-strain condition change at the crack tip during hold time, and how it affects on fatigue crack propagation. In this study, the influence of the tension hold and accompanying creep at crack tip on subsequent fatigue crack propagation behavior was evaluated by introducing single tension holds into pure cyclic loadings. The series of the experiments revealed that because of the tension hold, material degradation and stress relaxation occurred simultaneously ahead of crack tip. In the region where material was degraded, the resistance against crack propagation was reduced, while in the region where stress was relaxed, the crack driving force was lowered.
Investigation of the Steam Oxidation Resistance of Sanicro 25—A Material for Superheater and Reheaters in High Efficiency A-USC Fossil Power Plants
Authors: Bi Yanyan , Chai Guocai , Brodin Magnus
Published: March 2024

Sanicro 25 material is approved for use in pressure vessels and boilers according ASME code case 2752, 2753 and VdTUV blatt 555. It shows higher creep rupture strength than any other austenitic stainless steels available today. It is a material for superheater and reheaters, enabling higher steam parameters of up to about 650 °C steam (ie about max 700 °C metal) without the need for expensive nickel based alloys. The aim of the present study is the investigation of the steam oxidation resistance of the Sanicro 25. The long term test was conducted in the temperature range 600 -750 °C up to 20 000 hours. The morphology of the oxide scale and the microstructure of the bulk material were investigated. In addition, the effect of surface finish and pressure on the steam oxidation were also studied.
Characterization of the Microstructural Evolution of Aged Super 304H (UNS S30432) Advanced Austenitic Stainless Steel
Authors: Pulsford C. , Jepson M. A. E. , Thompson R. C. , Lolla T. , Siefert J.
Published: March 2024

Advanced austenitic stainless steels, such as Super 304H, have been used in reheater and superheater tubes in supercritical and ultra-supercritical power plants for many years now. It is important to characterize the microstructure of ex-service reheater and superheater tubes as this will help researchers understand the long-term microstructural evolution and degradation of the material, which can impact the performance and lifetime of the components that are in service. In this research, the microstructure of an ex-service Super 304H reheater tube that has been in service for 99,000 hours at an approximate metal temperature of 873K (600°C) has been characterized. The characterization techniques used were electron microscopy-based and included imaging and chemical analysis techniques. Seven phases were observed as a result of the characterization work. The phases observed were MX carbonitrides rich in niobium, copper-rich particles, M23C6, sigma phase, Z phase, a cored phase, and a BCC phase.
Modelling Hot Corrosion Damage in Industrial Gas Turbines
Authors: Sumner J , Simms N J , Kulkarni A
Published: March 2024

Key components within gas turbines, such as the blades, can be susceptible to a range of degradation mechanisms, including hot corrosion. Hot corrosion type mechanisms describe a sequence of events that include the growth and fluxing of protective oxide scales followed by the degradation of the underlying coating/alloy; this can significantly reduce component lifetimes. To better understand the progress of this type of damage mechanism, a model of hot corrosion progression with both time and corrosive deposit flux is presented for IN738LC and compared to experimental test data collected at 700 °C for four different deposit fluxes. One approach to the interpolation of model parameters between these four fluxes is illustrated. Of particular importance is that the model accounts for the statistical variation in metal loss though the use of Weibull statistics.
Weld Solidification Behavior and Performance of Nickel-Base Superalloy GH750 for Use in 700 °C Advanced Ultra-Supercritical Boiler
Authors: Zhao Shuangqun , Wang Yanfeng , Li Qiang , Fu Rui
Published: March 2024

A new nickel-base superalloy GH750 has been developed as boiler tube of advanced ultrasupercritical (A-USC) power plants at temperatures about and above 750°C in China. This paper researched the weld solidification of GH750 filler metal, microstructure development and property of GH750 welded joint by gas tungsten arc weld. Liquid fraction and liquid composition variation under non-equilibrium state were calculated by thermo-dynamic calculation. The weld microstructure and the composition in the dendrite core and interdendritic region were analyzed by SEM(EDX) in detail. The investigated results show that there is an obvious segregation of precipitation-strengthening elements during the weld solidification. Titanium and Niobium are the major segregation elements and segregates in the interdendritic region. It was found that the changing tendency of the elements’ segregation distribution during the solidification of GH750 deposit metal is agree with the thermodynamic calculation results. Till to 3,000hrs’ long exposure at 750°C and 800°C, in comparison with the region of dendrite core of solidification microstructure, not only the coarsening and the accumulation of γʹ particles are remarkable in the interdendritic region, but also the small quantity of the blocky and needle like η phases from. The preliminary experimental results indicate that the weakening effect of creep-rupture property of the welded joint is not serious compared with GH750 itself.
Creep Life Assessment of γ′ Precipitation Strengthened Ni-Based Superalloys for High Efficiency Turbine Components
Authors: Oinuma Shun , Takaku Reki , Nakatani Yujiro , Takeyama Masao
Published: March 2024

700°C advanced ultra-supercritical system and supercritical CO2 turbine system are developed for high efficiency turbine systems for next generation. This study covered the feasibility of creep life assessment of γ’-Ni3(Al,Ti) precipitation strengthened Ni-based superalloy rotor material, TOS1X-2, a modified alloy of UNS N06617 for these systems, based on hardness measurement method. It was found that the hardness of TOS1X-2 was governed by the change in precipitation strengthening and strain hardening during creep. The clear relationship between hardness increase in crept portion and macroscopic creep strain was observed, suggesting that it might be possible to estimate the creep strain or initiation of acceleration from hardness measurement. Microstructure inhomogeneity and microstructure evolutions during creep especially focused on dispersion of creep strain were characterized by EBSD quantitative analysis. It was found that creep strain was accumulated along the grain boundary, while it was relatively absent in coarse grains with low Schmid factor of {111} <110> slip system in fcc structure. The upper limit of hardness scatter band is thought to be important, since it represents the local and critical creep damage of the alloy.
Microstructural Evolution of a Creep Aged Tempered Martensitic Ferritic Steel during Welding
Authors: Marx G , Westraadt JE , Neethling JH , Pete T , Bezuidenhout M
Published: March 2024

The present study presents a detailed investigation on the evolution of the microstructure during welding on virgin and long-term service exposed (creep aged 1 = 535°C; 16.1 MPa; 156 kh and creep aged 2 = 555°C; 17.0 MPa; 130 kh) 12% Cr (X20CrMoV11-1) martensitic steel. This study was carried out in order to understand the impact of welding on prior creep exposed Tempered martensite ferritic (TMF) steel and to explain the preferential failure of weldments in the fine grained heat affected zone (FGHAZ) of the creep aged material side instead of the new material side. Gleeble simulation (Tp = 980°C; heating rate = 200 °C/s; holding time = 4 seconds) of the FGHAZ was performed on the materials to create homogeneous microstructures for the investigation. Quantitative microstructural investigations were conducted on the parent plate and simulated FGHAZ materials using advanced electron microscopy to quantify: a) voids, b) dislocation density, c) sub-grains, and d) precipitates (M23C6, MX, Laves, Z-phase) in the materials. Semi-automated image analysis was performed using the image analysis software MIPARTM. The pre-existing creep voids in the creep aged parent material and the large M23C6 carbides (Ø > 300 nm) in the FGHAZ after welding are proposed as the main microstructural contributions that could accelerate Type IV failure on the creep aged side of TMF steel weldments.
Keabsahan Kontrak yang dibuat oleh Artificial Intelligence Menurut Hukum Positif di Indonesia
Authors: Nurzaman Jajang , Fidhayanti Dwi
Published: March 2024

Tujuan dari penelitian ini adalah untuk mengetahui apakah kontrak yang dibuat oleh AI memenuhi syarat keabsahan sesuai dengan ketentuan pasal 1320 KUH Perdata. Serta memberikan pemahaman yang lebih baik tentang implikasi hukum dan regulasi yang berkaitan dengan penggunaan AI dalam pembuatan kontrak. Jenis penelitian yang digunakan adalah yuridis normatif. Pendekatan penelitian ini menggunakan pendekatan undang-undang (Statute Approach) dan konseptual (Conceptual Approach). Sumber bahan hukum yang digunakan berupa bahan hukum premier yang terdiri dari undang-undang yang mengatur tentang keperdataan dan undang-undang yang mengatur tentang regulasi AI. Adapun bahan hukum sekunder berupa jurnal yang membahas tentang kedudukan hukum AI dan legal tech beserta artikel ilmiah. Teknik pengumpulan bahan hukum dalam penelitian hukum normatif dilakukan dengan cara studi pustaka (Library Research) berupa data sekunder sebagai bahan dasar untuk diteliti dengan cara mengadakan penelusuran terhadap peraturan-peraturan dan literatur-literatur lain berkaitan dengan permasalahan yang diteliti. Hasil penelitian ini menunjukan bahwa AI memiliki potensi besar dalam pembuatan kontrak, tetapi perlu diperhatikan kedudukan hukumnya. Dengan memandang AI sebagai subjek hukum dengan pemilik atau pengguna yang bertanggung jawab, kontrak yang dibuat oleh AI dapat dianggap sah sesuai dengan hukum positif Indonesia.
The Application Of The Principle Of Judges Freedom On SEMA Number 2 Of 2023
Authors: Hidayati Tri , Aulia Ajeng Hijriatul , Wiraganti Risna Wendy
Published: March 2024

This study aims to determine the position of the Supreme Court Circular Letter in the judicial system in Indonesia and the binding force of Supreme Court Circular Letter Number 2 of 2023 concerning Guidelines for Judges in Handling Applications for Registration of Marriages of Different Religions (Supreme Court Circular Letter number 2 of 2023) on the freedom of District Court judges in handling applications for registration of marriages of different religions in Indonesia. This research is normative legal research, using statutory and conceptual approaches and analyzed using content analysis techniques. The findings are that the Supreme Court Circular Letter does not have the status of a binding legal norm but has a moral force that binds judges in the judicial environment. Decisions in Supreme Court Circulars often reflect in-depth legal interpretation and the experience of judicial practitioners. Supreme Court Circular Letter No. 2 of 2023 aims to strengthen and direct the principle of judges' independence towards the achievement of better justice. The implementation of Supreme Court Circular Number 2 of 2023 will depend on the awareness and commitment of judges, as well as the full support of the judiciary and other relevant stakeholders.
Analisa Yuridis Tingginya Dispensasi Perkawinan di Kota Banjarmasin
Authors: Septarina Muthia , Munajah Munajah , Nahdhah Nahdhah
Published: March 2024

Di Indonesia pernikahan merupakan hak setiap warga Negara. Di dalam Pasal 28B ayat(1) Undang-Undang Dasar Negara Republik Indonesia (UUD-NRI) menjamin akan hal ini. Pasal tersebut berbunyi :”Setiap orang berhak membentuk keluarga dan melanjutkan keturunan melalui perkawinan yang sah.” Aturan dasar tersebut diwujudkan dengan keberadaan UndangUndang Nomor 1 Tahun 1974 Tentang Perkawinan (UUP). Pada dasarnya, setiap orang berhak untuk melangsungkan pernikahan, termasuk orang yang masih terkategori anak. Akan tetapi dengan pertimbangan perkawinan pada usia anak menimbulkan dampak negatif bagi tumbuh kembang anak dan akan menyebabkan tidak terpenuhinya hak dasar anak, Pemerintah kemudian merevisi mengenai batasan usia kawin melalui Undang-Undang Nomor 16 Tahun 2019. Pria maupun wanita ditentukan usia minimal untuk menikah adalah 19 (sembilan belas) tahun. Apabila akan melangsungkan pernikahan di bawah usia tersebut, maka orang tua pihak pria dan/atau orang tua pihak wanita dapat meminta dispensasi kepada Pengadilan. Pengadilan Agama memberikan izin kawin karena alasan mendesak. Pada kenyataannya permohonan dispensasi kawin ini angkanya cukup tinggi. Metode yang digunakan dalam penelitian ini adalah yuridis sosiologis yaitu penelitian yang akan mengkaji dari sisi perundang-undangan sekaligus dengan memperhatikan kenyataan yang terjadi di masyarakat dari tingginya angka dispensasi kawin. Hasil dari penelitian ini yaitu Faktor Penyebab Pengajuan Dispensasi Perkawinan di Kota  Banjarmasin, yaitu : pertama,  dampak dari ketentuan usia 19 tahun maka meningkatkan permohonan dispensasi nikan serta kekhawatiran orangtua terhadap pergaulan bebas. Kedua,   Penerapan Ketentuan Dispensasi Perkawinan di Kota Banjarmasin untuk menolak atau mengabulkan dengan memperhatikan apakah calon suami sudah bekerja atau belum atau apakah calon istri masih sekolah ataukah tidak memperhatikan pula kepada alasan mendesak sebagaimana ketentuan di dalam PERMA.
The Development of Customer Journey Mapping in Digital-Based Start-up Businesses
Authors: Lahadcni Realita , Zulkifli Syerie , Sekar Teara Noviyani
Published: March 2024

This research is motivated by the large number of developments in digital start-ups and large digital-based companies that are starting to understand customers. This research aims to analyze Customer Journey Mapping (CJM) and examine what instruments are involved in digital-based start-up companies to finally develop a process model for CJM in digital-based start-up businesses. This study uses the qualitative case study method on digital-based start-up companies in Magelang and Yogyakarta, Indonesia by conducting in-depth interviews with 5 start-up owners/CEOs. The results of this research show that CJM has three stages that customers will go through and the company will respond to. In the form of prepurchase, purchase, and post-purchase stages, all stages simultaneously relate to creating a unique experience. For practical implication, this model can be maximized in start-up businesses to acquire loyal customers.
IN SILICO STUDIES FOR ANTI-BREAST CANCER ACMELLA OLERACEA (L.) FLOWERS
Authors: Amrilah Muhammad Shofi , Hilman Rifqi
Published: March 2024

The study of the efficacy of Acmella oleracea (L.) flowers on breast cancer is still in its early stages. The molecular interaction mechanisms underlying Acmella oleracea's anti-breast cancer activity will be elucidated using in-silico analysis. For this study, seventeen bioactive compounds were used: spilanthol, alpha- and beta-amyrin ester, stigmasterol, beta-sitosterol, alpha-1-sitosterol, 3-acetylaleuritic acid, scopoletin, vanillic acid, trans-ferulic, (72,9E)-2-oxo-undeca-7,9-dienyl 3-methylbut-2-enoate, beta-caryophyllene, beta-pinene, myrcene, caryophyllene oxide, and limone Canonical smiles were obtained from PubChem and inserted into the PASS server to determine biological activity. Several compounds were docked with protein targets, such as ESR1, MAP2K2, and PGR. We used Pyrx 0.8 software for anchoring molecular interaction and Discovery Studio software to visualize the complex binding. In terms of Antineoplastic, apoptosis agonist, caspase-3, caspase-8 stimulant, ovulation inhibitor, steroid synthesis inhibitor, and TP53 expression enhancer, all the compounds tested positive for anticancer activity. According to Swiss ADME and protox analysis, Acmella oleracea flowers have the potential to modulate apoptosis and cell growth. More research is required to confirm the role of Acmella oleracea bioactive compounds in developing target cancers. The study reveals that Acmella oleracea has numerous bioactive chemicals advantageous for cancer therapy by inducing apoptosis through interaction with ESR1, MAPK2, and PGR protein.
POTENTIAL KETAPANG (Terminalia cattapa) LEAF EXTRACT AS A DOXORUBICIN CO-CHEMOTHERAPY AGENT ON BREAST (T47D) AND CERVIX (HeLa) CANCER CELL LINES
Authors: Sundhani Elza , Solehah Senja Nur , Septiadi Binaripan , Nurulita Nunuk Aries
Published: March 2024

Doxorubicin (DOX) is chemotherapy for breast and cervical cancer with serious side effects. Ketapang (Terminalia cattapa) is a potential plant as a co-chemotherapy agent. The purpose of this research was to examine the sensitivity of DOX as a cytotoxicity drug in combination with ethanolic extracts of ketapang leaves (EKL) against T47D and HeLa cancer cells. Cytotoxicity was determined using the MTT assay, with DOX concentration series (0.625-40 nM for T47D and 0.5-6 M for HeLa) and EKL (50-1000 mg/mL) used in combination with the study. DOX and EKL combination assays utilizing their respective IC50 values were performed in T47D cells and HeLa cells, and the results were used to calculate the Combination Index (CI). Furthermore, the doubling time method was used to investigate the combination of DOX and EKL proliferation inhibition on both cell lines. DOX and EKL had IC50 values of 158 nM and 30 mg/mL for T47D, respectively, and 3.4 M and 640 mg/mL for HeLa cell growth. While DOX and EKL have a synergistic effect on T47D cells, their combined effect on HeLa cells is cytotoxic and dose-dependent. EKL increases the inhibitory effect of DOX on the proliferation of T47D and HeLa cancer cells. In T47D cells, the combination of DOX and EKL has a higher potential for cytotoxic and antiproliferative activity than in HeLa cells