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Proceedings Papers
AM-EPRI2013, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Seventh International Conference, 1116-1126, October 22–25, 2013,
... toughness Advances in Materials Technology for Fossil Power Plants Proceedings from the Seventh International Conference October 22 25, 2013, Waikoloa, Hawaii, USA httpsdoi.org/10.31399/asm.cp.am-epri-2013p1116 Copyright © 2014 Electric Power Research Institute, Inc. Distributed by ASM International®...
Abstract
View Papertitled, Effect of Copper Addition on the <span class="search-highlight">Toughness</span> of New Z-Phase Strengthened 12% Chromium Steels
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for content titled, Effect of Copper Addition on the <span class="search-highlight">Toughness</span> of New Z-Phase Strengthened 12% Chromium Steels
Two Z-phase strengthened test steels with similar chemical composition were studied. The main difference in composition is the addition of 1 wt% Cu into one of the steels (referred to as “ZCu”). Mechanical testing was performed. The impact strength is very different: 3 J vs. 46.3 J, for the original and the Z-Cu steel, respectively. In the original steel that contains no Cu, much more Laves-phase (Fe 2 (W,Mo)) precipitates had formed along the prior austenite grain boundaries than in the steel with Cu addition. This is believed to be the reason for the difference in impact strength. Furthermore, the Cu addition also influenced the morphology of Laves-phase precipitates; fine rod-shaped instead of coarse equiaxed Laves-phase particles were observed in Z-Cu steel in comparison to the original steel. No partitioning of Cu into the Laves-phase particles was detected by using atom probe tomography (APT). The main function of Cu seems to be the formation of Cu precipitates that act as nucleation site for Laves-phase.
Proceedings Papers
AM-EPRI2004, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Fourth International Conference, 1136-1145, October 25–28, 2004,
... Abstract Effects of Ni content and heat treatment condition on impact toughness and creep strength of precipitation strengthened 15Cr ferritic steels were investigated in order to discuss a possibility of improvement in both mechanical properties. Both creep strength and impact toughness...
Abstract
View Papertitled, Improvement in Creep Strength and Impact <span class="search-highlight">Toughness</span> of High Cr Heat Resistant Steel based on Ferrite Matrix
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for content titled, Improvement in Creep Strength and Impact <span class="search-highlight">Toughness</span> of High Cr Heat Resistant Steel based on Ferrite Matrix
Effects of Ni content and heat treatment condition on impact toughness and creep strength of precipitation strengthened 15Cr ferritic steels were investigated in order to discuss a possibility of improvement in both mechanical properties. Both creep strength and impact toughness of the developing steels were improved drastically by solid solution treatment with water quenching. However, an addition of Ni reduced the long-term creep strength of the steels, though Ni was effective in improvement in impact toughness. It was found that water quenching suppressed formation of coarse block type particles and precipitate free zones around them, and precipitation of plate type fine particles and thermal stability of them within ferrite phase were promoted by solid solution treatment with water quenching. However, martensite phase with sparsely distributed coarse block type particles were formed in the Ni added steels, and such microstructure reduced the precipitation strengthening effect slightly. On the other hand, increase in impact values of the steel indicated no relation to volume fraction of martensite phase. It was supposed that the impact toughness of ferrite phase itself was improved by solid solution treatment and addition of Ni.
Proceedings Papers
AM-EPRI2010, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Sixth International Conference, 1014-1029, August 31–September 3, 2010,
... Abstract The toughness of girth welds in 9Cr-1Mo-V and 9Cr-0.5Mo-V steel seamless pipe (ASME SA-335 Grades P91 and P92, respectively) made using the flux-cored arc welding (FCAW) process was evaluated. Electrodes from two different suppliers were used for production quality welding of each...
Abstract
View Papertitled, <span class="search-highlight">Toughness</span> Evaluation of Welds in 9Cr-1Mo-V and 9Cr-0.5Mo-V Steels Made Using the Flux-Cored Arc Welding (FCAW) Process
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for content titled, <span class="search-highlight">Toughness</span> Evaluation of Welds in 9Cr-1Mo-V and 9Cr-0.5Mo-V Steels Made Using the Flux-Cored Arc Welding (FCAW) Process
The toughness of girth welds in 9Cr-1Mo-V and 9Cr-0.5Mo-V steel seamless pipe (ASME SA-335 Grades P91 and P92, respectively) made using the flux-cored arc welding (FCAW) process was evaluated. Electrodes from two different suppliers were used for production quality welding of each steel. The welds received post-weld heat-treatment (PWHT) in accordance with the requirements of the ASME Code. The objective of the work was to determine if the fracture toughness of the FCAW welds was acceptable for high-temperature steam piping. Toughness was measured using standard sized Charpy V-notch impact specimens. The specimens were oriented transverse to the weld seam with notch located approximately in the center of the weld metal and parallel to the direction of weld seam. Full-range (lower to upper shelf) Charpy impact energy and shear area curves were developed for each weld joint. These were used to estimate the temperatures corresponding to 30 ft-lb average impact energy. The estimated temperatures were well below the service temperature but were above the typical hydrostatic test temperature.
Proceedings Papers
AM-EPRI2019, 2019 Joint EPRI – 123HiMAT International Conference on Advances in High-Temperature Materials, 11-21, October 21–24, 2019,
... compositions were cut in the diffusion layers by focused ion beam milling. The fracture toughness and the critical resolved shear stress (CRSS) were measured by in-situ microcantilever bending tests and micropillar compression tests, respectively. The hardness, Young's modulus and CRSS are nearly constant...
Abstract
View Papertitled, Micromechanics of Co-Nb Laves Phases: Strength, Fracture <span class="search-highlight">Toughness</span>, and Hardness as Function of Composition and Crystal Structure
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for content titled, Micromechanics of Co-Nb Laves Phases: Strength, Fracture <span class="search-highlight">Toughness</span>, and Hardness as Function of Composition and Crystal Structure
Laves phases are intermetallic phases well known for their excellent strength at high temperatures but also for their pronounced brittleness at low temperatures. Especially in high-alloyed steels, Laves phases were long time regarded as detrimental phases as they were found to embrittle the material. Perusing the more recent literature, it seems the negative opinion about the Laves phases has changed during the last years. It is reported that, if the precipitation morphology is properly controlled, transition metal-based Laves phases can act as effective strengthening phases in heat resistant steels without causing embrittlement. For a targeted materials development, the mechanical properties of pure Laves phases should be known. However, the basic knowledge and understanding of the mechanical behavior of Laves phases is very limited. Here we present an overview of experimental results obtained by micromechanical testing of single-crystalline NbCo 2 Laves phase samples with varying crystal structure, orientation, and composition. For this purpose, diffusion layers with concentration gradients covering the complete homogeneity ranges of the hexagonal C14, cubic C15 and hexagonal C36 NbCo 2 Laves phases were grown by the diffusion couple technique. The hardness and Young's modulus of NbCo 2 were probed by nanoindentation scans along the concentration gradient. Single-phase and single crystalline microcantilevers and micropillars of the NbCo 2 Laves phase with different compositions were cut in the diffusion layers by focused ion beam milling. The fracture toughness and the critical resolved shear stress (CRSS) were measured by in-situ microcantilever bending tests and micropillar compression tests, respectively. The hardness, Young's modulus and CRSS are nearly constant within the extended composition range of the cubic C15 Laves phase, but clearly decrease when the composition approaches the boundaries of the homogeneity range where the C15 structure transforms to the off stoichiometric, hexagonal C36 and C14 structure on the Co-rich and Nb-rich, respectively. In contrast, microcantilever fracture tests do not show this effect but indicate that the fracture toughness is independent of crystal structure and chemical composition of the NbCo 2 Laves phase.
Proceedings Papers
AM-EPRI2019, 2019 Joint EPRI – 123HiMAT International Conference on Advances in High-Temperature Materials, 405-415, October 21–24, 2019,
... Abstract In the present study, the Inconel 617B superalloy welded trial rotor was fabricated by narrow gap tungsten inert gas (NG-TIG) welding and the effects of temperature on fracture toughness of its welded joint were investigated at 650 ℃ and 730 ℃. Fracture toughness (J0.2) of the base...
Abstract
View Papertitled, Effect of Temperature on Fracture <span class="search-highlight">Toughness</span> of Inconel 617B Superalloy Welded Joint
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for content titled, Effect of Temperature on Fracture <span class="search-highlight">Toughness</span> of Inconel 617B Superalloy Welded Joint
In the present study, the Inconel 617B superalloy welded trial rotor was fabricated by narrow gap tungsten inert gas (NG-TIG) welding and the effects of temperature on fracture toughness of its welded joint were investigated at 650 ℃ and 730 ℃. Fracture toughness (J0.2) of the base metal was much higher than that of the weld metal at the same temperature, which was attributed to its excellent macroscopical plasticity and the interactions of strain localization, misorientation, and coincidence site lattice (CSL) boundaries. For the base metal, the value of J0.2 was higher at 730 ℃ than at 650 ℃, resulting from the appreciable increase in ductility and decrease in strain localization as the temperature increased. For the weld metal, higher temperature (730 ℃) reduced strength but hardly improved plasticity, and the regions of high strain localization uniformly distributed in the weld metal, resulting in completely tearing the whole interface apart and lower fracture toughness of the weld metal.
Proceedings Papers
AM-EPRI2019, 2019 Joint EPRI – 123HiMAT International Conference on Advances in High-Temperature Materials, 1351-1360, October 21–24, 2019,
... be a worthy candidate for use in production because it has superior creep resistance. At the same time, resistance to cyclic and dynamic loads is very important. In this work, we studied the low cycle fatigue (LCF) properties at room and elevated (500-650°C) temperatures and Charpy impact toughness...
Abstract
View Papertitled, Low Cycle Fatigue Properties and Impact <span class="search-highlight">Toughness</span> of Advanced 10% Cr Steel with High Boron and Low Nitrogen Contents
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for content titled, Low Cycle Fatigue Properties and Impact <span class="search-highlight">Toughness</span> of Advanced 10% Cr Steel with High Boron and Low Nitrogen Contents
9-12%Cr martensitic steels can be applied to the next highest temperature components such as boiler tracts, steam pipelines and turbines of advanced ultra-supercritical power plants with steam temperatures of 650°C. New 10%Cr martensitic steels with high B and low N contents can be a worthy candidate for use in production because it has superior creep resistance. At the same time, resistance to cyclic and dynamic loads is very important. In this work, we studied the low cycle fatigue (LCF) properties at room and elevated (500-650°C) temperatures and Charpy impact toughness at temperatures ranging from -196…100°C of advanced 10% Cr martensitic steel with high B and low N contents. The effect of new alloying scheme and corresponding peculiarities of M 23 C 6 carbides on the low cycle fatigue resistance and impact toughness of the 10%Cr martensitic steel is analyzed. It is revealed that fine and densely distributed carbides has no effect on the fatigue resistance except for the slight improvement of fatigue life at small strain amplitudes and shift the ductile-brittle transition temperature (DBTT) to higher but satisfactory value of +10°C as compared to other high-chromium martensitic steels.
Proceedings Papers
AM-EPRI2024, Advances in Materials, Manufacturing, and Repair for Power Plants: Proceedings from the Tenth International Conference, 662-668, February 25–28, 2025,
... of the fraction of transition metals and vacancy could be possible for designing (Ti.TM)C x with high strength and toughness. shear modulus stoichiometric effects titanium carbide toughness Advances in Materials, Manufacturing, and Repair for Power Plants: Proceedings from the Tenth International...
Abstract
View Papertitled, Off-Stoichiometric Effect on Properties of TiC
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for content titled, Off-Stoichiometric Effect on Properties of TiC
Titanium carbide (TiC) have a wide off-stoichiometric composition when in equilibrium with the metallic phase. In this case, the off-stoichiometric effect allows the substitution of other transition metals (TM) at the Ti site and vacancy formation at the C site. It leads to changes in the material properties of TiC. Therefore, it is important to investigate the change of material properties with the off-stoichiometric effect. In this study, the elastic properties of (Ti, TM)C x were focused on. To investigate the change of elastic properties with various transition metals substitution, elastic properties were evaluated by first-principles calculations. From the calculation, it was suggested that bulk modulus is controlled by the 1st and 2nd nearest neighbor bond, but shear modulus is mainly affected by only the 1 st nearest neighbor bond. Therefore, it was indicated that proper control of the fraction of transition metals and vacancy could be possible for designing (Ti.TM)C x with high strength and toughness.
Proceedings Papers
AM-EPRI2019, 2019 Joint EPRI – 123HiMAT International Conference on Advances in High-Temperature Materials, 1069-1078, October 21–24, 2019,
... cool was carried out. The hardness and impact toughness of welded joints were measured, and the microstructure evolution after aging at 750℃ for 3000h was investigated by scanning electron microscopy(SEM). The results show that, during the aging process, the hardness of weld metal increases firstly...
Abstract
View Papertitled, Study on GTAW Welded Joint of Nimonic 263 Alloy after Aging at 750℃ for Gas Turbine Transition Pieces
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for content titled, Study on GTAW Welded Joint of Nimonic 263 Alloy after Aging at 750℃ for Gas Turbine Transition Pieces
Nimonic 263 alloy was selected for gas turbine combustor transition piece due to its excellent high temperature mechanical performance. In present work, Nimonic 263 alloy plate with thickness of 5mm was welded using 263 filler metal by GTAW, then post weld heat treatment of 800℃/8h/air cool was carried out. The hardness and impact toughness of welded joints were measured, and the microstructure evolution after aging at 750℃ for 3000h was investigated by scanning electron microscopy(SEM). The results show that, during the aging process, the hardness of weld metal increases firstly and then decreases. The impact toughness decreases significantly at first and then increase. Furthermore, some fluctuations can be detected in hardness and impact toughness after long-term thermal exposure. The significant decrease in the impact toughness of the aged welded joints mainly results from the precipitation of η phase around grain boundary and intergranular MC phase. The hardness of weld metal increases due to the precipitation of more carbides and γ′ phase after 1000h aging, then decreases owing to the growth of γ′ phase after 3000h aging.
Proceedings Papers
AM-EPRI2024, Advances in Materials, Manufacturing, and Repair for Power Plants: Proceedings from the Tenth International Conference, 1249-1256, February 25–28, 2025,
...- 0.1Ta-Mn-Si-C, in weight percent, developed at Oak Ridge National Laboratory in 2007. The alloy design includes reducing the hardness in the as-welded condition for improving toughness, while increasing the hardenability for preserving the high-temperature mechanical performance such as creep-rupture...
Abstract
View Papertitled, Development of PWHT-Free, Reduced Activation Creep-Strength Enhanced Bainitic Ferritic Steel for Large-Scale Fusion Reactor Components
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for content titled, Development of PWHT-Free, Reduced Activation Creep-Strength Enhanced Bainitic Ferritic Steel for Large-Scale Fusion Reactor Components
A compositional modification has been proposed to validate an alloy design which potentially eliminates the requirement of post-weld heat treatment (PWHT) while preserving the advantage of mechanical properties in a reduced activation bainitic ferritic steel based on Fe-3Cr-3W-0.2V- 0.1Ta-Mn-Si-C, in weight percent, developed at Oak Ridge National Laboratory in 2007. The alloy design includes reducing the hardness in the as-welded condition for improving toughness, while increasing the hardenability for preserving the high-temperature mechanical performance such as creep-rupture resistance in the original steel. To achieve such a design, a composition range with a reduced C content combining with an increased Mn content has been proposed and investigated. Newly proposed “modified” steel successfully achieved an improved impact toughness in the as- welded condition, while the creep-rupture performance across the weldments without PWHT demonstrated ~50% improvement of the creep strength compared to that of the original steel weldment after PWHT. The obtained results strongly support the validity of the proposed alloy design.
Proceedings Papers
AM-EPRI2024, Advances in Materials, Manufacturing, and Repair for Power Plants: Proceedings from the Tenth International Conference, 855-860, February 25–28, 2025,
... (ERNiCrMo-3) filler materials. Specimens were welded with the temper-bead/controlled deposition welding technique. The weld processes used were HP-GTAW, GMAW and SMAW. The fatigue performance, HAZ hardness and toughness of the weld samples was evaluated. The HP-GTAW welds exhibited an order of magnitude...
Abstract
View Papertitled, Weld Process Effects on Fatigue Performance in the Repair of Coke Drums
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for content titled, Weld Process Effects on Fatigue Performance in the Repair of Coke Drums
Coke drums experience failures in through-wall cracking throughout their operating life, resulting from low cycle fatigue. Coke drums are typically fabricated from Chrome Moly (CrMo) steels. This study was performed on P4 (1.25Cr-0.5Mo) base material using ER70S-B2L and Alloy 625 (ERNiCrMo-3) filler materials. Specimens were welded with the temper-bead/controlled deposition welding technique. The weld processes used were HP-GTAW, GMAW and SMAW. The fatigue performance, HAZ hardness and toughness of the weld samples was evaluated. The HP-GTAW welds exhibited an order of magnitude improvement in fatigue performance when compared to the other weld processes using ER70S-B2L filler material. The HP-GTAW welds also exhibited improved HAZ hardness and toughness when compared to the other weld processes. This presentation will introduce the HP-GTAW process, its features, and benefits and where it is applied in Coke drum repair welding. Comparative test results of the different weld processes for fatigue performance, HAZ tempering, and toughness will also be presented.
Proceedings Papers
AM-EPRI2016, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Eighth International Conference, 931-938, October 11–14, 2016,
... strength of base metal Creep ductility Toughness EXPERIMENTAL PROCEDURE Normalized and tempered laboratory melted plates, the product pipes and tubes of SAVE12AD were prepared, while welded joint tubes with the filler wires of W62-10CMWV-Co (Gr. 92) and Ni base filler wire ERNiCr-3 (Alloy82) were prepared...
Abstract
View Papertitled, Property of 9Cr-3W-3Co-Nd-B Heat-Resistant Steel SAVE12AD Welded Joint
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for content titled, Property of 9Cr-3W-3Co-Nd-B Heat-Resistant Steel SAVE12AD Welded Joint
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.
Proceedings Papers
AM-EPRI2004, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Fourth International Conference, 692-702, October 25–28, 2004,
... Abstract The small punch (SP) test technique can generate tensile, toughness, and creep strength data from very small specimens, enabling nondestructive sampling from large components. This has accelerated industry interest in SP, particularly in the energy sector. A round-robin for the SP...
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View Papertitled, The Small Punch Test Method: Results from a European Creep Testing Round Robin
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for content titled, The Small Punch Test Method: Results from a European Creep Testing Round Robin
The small punch (SP) test technique can generate tensile, toughness, and creep strength data from very small specimens, enabling nondestructive sampling from large components. This has accelerated industry interest in SP, particularly in the energy sector. A round-robin for the SP creep test was organized within the EPERC network on a 1CrMoV rotor steel, primarily to contribute to harmonizing the test procedure for this emerging method. This presentation analyzes the SP creep test results performed at several temperatures and one load level to assess their inter-comparability and interpret the results concerning conventional uniaxial creep tests. The SP loading geometry appeared to be a key parameter in evaluating the SP results, particularly for correlation with uniaxial creep behavior. A standardization initiative for the SP test method, including creep as well as low-temperature testing for determining tensile and toughness properties of metallic materials, has recently started via a CEN Workshop.
Proceedings Papers
AM-EPRI2024, Advances in Materials, Manufacturing, and Repair for Power Plants: Proceedings from the Tenth International Conference, 1279-1288, February 25–28, 2025,
..., the oxidation resistance of the rapidly solidified MoSiBTiC alloy at 1100 °C was dramatically improved, probably due to the microstructure refinement effect with ultrafine grains. However, the fracture toughness value of the rapidly solidified MoSiBTiC alloy was about 8 MPa·m 1/2 , less than half of the cast...
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View Papertitled, Oxidation and Mechanical Properties of Ultrafine-Grained MoSiBTiC Alloy Produced by Rapid Solidification
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for content titled, Oxidation and Mechanical Properties of Ultrafine-Grained MoSiBTiC Alloy Produced by Rapid Solidification
The microstructural evolution of the MoSiBTiC alloy by rapid solidification and its effect on oxidation and mechanical properties were investigated in this study. A Mo-5Si-10B-10Ti-10C (at%) alloy was produced by a conventional arc-melting technique in an Ar atmosphere, and then it was rapidly solidified by tilt-casting into a rod-shaped copper hearth. Vickers hardness values increased drastically above 1000 Hv due to the microstructure refinement through rapid solidification. They rose from the center toward the outer surface, ranging from about 1100 to 1300 Hv. Interestingly, the oxidation resistance of the rapidly solidified MoSiBTiC alloy at 1100 °C was dramatically improved, probably due to the microstructure refinement effect with ultrafine grains. However, the fracture toughness value of the rapidly solidified MoSiBTiC alloy was about 8 MPa·m 1/2 , less than half of the cast and heat-treated MoSiBTiC alloy previously reported. Heat treatment and composition optimization will further improve the performance of the rapidly solidified MoSiBTiC alloy.
Proceedings Papers
AM-EPRI2019, 2019 Joint EPRI – 123HiMAT International Conference on Advances in High-Temperature Materials, 116-122, October 21–24, 2019,
...°C. Despite of the presence of coarse W-rich particles, the impact toughness of the low-temperature- homogenized steel in the tempered condition was significantly higher than that of the steel homogenized at 1200°C creep rate dispersion hardening impact toughness martensitic stainless steel...
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View Papertitled, Effect of Heat Treatment on Microstructure and Mechanical Properties of an Advanced Ta-Alloyed 9%Cr Steel
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for content titled, Effect of Heat Treatment on Microstructure and Mechanical Properties of an Advanced Ta-Alloyed 9%Cr Steel
The microstructures of an advanced Ta-added 9Cr-3Co-2W-Mo steel with increased boron content that has been homogenized at different temperatures were investigated. The chains of coarse W-rich particles were observed in the steel after homogenization at 1150°C for 24 h. These particles remained in the microstructure after normalization and tempering. Such additional dispersion hardening in the initial state of the studied steel decreased the creep rate in transient region. However, the duration of steady state creep and overall creep time was increased in the samples homogenized at 1200°C. Despite of the presence of coarse W-rich particles, the impact toughness of the low-temperature- homogenized steel in the tempered condition was significantly higher than that of the steel homogenized at 1200°C
Proceedings Papers
AM-EPRI2019, 2019 Joint EPRI – 123HiMAT International Conference on Advances in High-Temperature Materials, 830-835, October 21–24, 2019,
... and better than SiC/SiC ceramic matrix composites. Furthermore, the fracture toughness of the alloy is much better (>15 MPa(m) 1/2 ) than Mo-Si-B ternary alloys (<10 MPa(m) 1/2 ) even if the volume fraction of Mo solid solution is less than 50 %. The improvement of fracture toughness would be caused...
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View Papertitled, Effect of Off-Stoichiometry on Elastic Modulus of TiC Phase in Mo-TiC Ternary System
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for content titled, Effect of Off-Stoichiometry on Elastic Modulus of TiC Phase in Mo-TiC Ternary System
MoSiBTiC alloy is a promising material for advanced aerospace applications and next generation high pressure turbine blades in jet engines and gas turbines. It mainly consists of Mo solid solution, TiC and Mo 5 SiB 2 phases and has creep strength much stronger than Ni-base superalloys and better than SiC/SiC ceramic matrix composites. Furthermore, the fracture toughness of the alloy is much better (>15 MPa(m) 1/2 ) than Mo-Si-B ternary alloys (<10 MPa(m) 1/2 ) even if the volume fraction of Mo solid solution is less than 50 %. The improvement of fracture toughness would be caused not only by the continuity of Mo solid solution in solidification microstructure but also by TiC phase affecting as a fracture-resistant phase. In order to understand the microstructure evolution during solidification and the effect of TiC phase on the fracture toughness of the MoSiBTiC alloy, Mo-Ti-C ternary model alloys are dealt with in this study. Then, (1) liquidus surface projection and (2) isothermal section and the elastic moduli of TiC phase in equilibrium with Mo solid solution were focused on. The obtained liquidus surface projection suggests that the ternary transition peritectic reaction (L+ Mo 2 C->Mo+TiC) takes place in Mo-rich region. At 1800 °C, TiC phase in equilibrium with Mo phase contains at least 20.2 at% Mo and the Mo/TiC/Mo 2 C three phase region should exist around Mo-15Ti-10C.
Proceedings Papers
AM-EPRI2016, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Eighth International Conference, 1001-1009, October 11–14, 2016,
... was early overcome and was wrong. According to the present experience the T24 steel is welded with preheating at 150-250°C depending on the wall thickness and welded joint toughness in order to achieve required hardness and impact toughness values. Opinions on the T24 welded joints post weld heat treatment...
Abstract
View Papertitled, Secondary Hardening of T24 Steel Weld Joints Performed at Incorrect Interpass Temperature and Low Temperature Heat Treatment
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for content titled, Secondary Hardening of T24 Steel Weld Joints Performed at Incorrect Interpass Temperature and Low Temperature Heat Treatment
The efficiency of power plants is depending on the steam temperature and/or the steam pressure. Efficiency increasing from 35% to 42-45% require increasing of the steam temperature over 600°C and the pressure over 26 MPa. According to the designer opinion it is not profitable to use classical low alloy creep resistant steels 16Mo3, 13CrMo4-5 or 10CrMo9-10 for membrane waterwall construction for these service condition. New modified low alloy creep resistance T23 and T24 (7CrMoVTiB10-10) steels were developed for membrane waterwalls. Welding of these steels with small thickness (around 6.3 mm) should be enabled without preheating and post weld heat treatment (PWHT) due to the lower carbon content below 0.1%. High creep rupture strength (CRS) values are achieved by Ti, N and B elements alloyed to T24 steel. The original expectation that the welding small thickness without preheating was early overcome and was wrong. According to the present experience the T24 steel is welded with preheating at 150-250°C depending on the wall thickness and welded joint toughness in order to achieve required hardness and impact toughness values. Opinions on the T24 welded joints post weld heat treatment (PWHT) requirements are still inconsistent. Especially the membrane waterwalls of the supercritical power plants are still produced without PWHT.
Proceedings Papers
AM-EPRI2010, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Sixth International Conference, 1030-1044, August 31–September 3, 2010,
... flux-fill or other manufacturing irregularities. Properties were also known to vary, especially consistent toughness. Today, availability of numerous alloys is far more comprehensive. FCAW wires are manufactured for applications involving low carbon steels, low alloy steels for both high and low...
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View Papertitled, Flux Cored Wires for High Integrity Applications
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for content titled, Flux Cored Wires for High Integrity Applications
The use of flux-cored arc welding (FCAW) is rapidly gaining acceptance in a variety of industries. Much of the gains are due to advances in manufacturing technology that result in superior wires that satisfy both technical and operability concerns. Additionally, productivity gains and the ability to use unsophisticated welding equipment have made these wires very popular. This paper concentrates on FCAW wires that have been formulated to address chromium-molybdenum, nickel base, and stainless steels for high-temperature and environmental applications. Mechanical properties, including creep rupture strength and ductility data, as well as corrosion in environmental components, are discussed.
Proceedings Papers
AM-EPRI2013, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Seventh International Conference, 537-548, October 22–25, 2013,
... without PWHT is too high. It can be reduced to HV250 after PWHT. Figure 2: The hardness of welded joints of T23 tube 3.5 Temper brittleness of butt welds of T23 tube The impact toughness of T23 tube s butt welds at different post weld heat treatments is shown in Fig.3. The result shows that the impact...
Abstract
View Papertitled, Research on Water Wall Tubes and Welded Joints of 1000MW USC Tower Boiler
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In this paper, the performance of T23 and 12Cr1MoVG water wall tubes as well as their welded joints in engineering applications is reported. It was found that the T23 water wall tube may have water leak problems during its operation. In order to make sure the safe operation, leakage reasons of T23 water wall tube were analyzed and improvement measures were taken. Recommendations on the choice of water wall material of 1000MW USC tower boiler are given.
Proceedings Papers
AM-EPRI2004, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Fourth International Conference, 899-918, October 25–28, 2004,
... the framework of COST 522 program concerning the influence of simulation of element temperature operating conditions on Chaгpy V notch toughness, HV10 hardness, microstructure of simulated HAZ's, assessment of steel weldability, strength properties. The welded joints structure stability and HAZ after stress...
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View Papertitled, Stability of Similar and Dissimilar Welded Joints, High-Temperature Creep Resistant Martensitic Steels Containing 9% Cr
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This paper presents RAFAKO S.A. experience within the field of research and implementation of new group of creep-resistant steel grades with addition of tungsten, including the selection of filler metal, welding procedures and selected results of mechanical properties testing carried out during the implementation of welding process for elements of steam superheaters of the boilers with supercritical parameters. It summarizes the experience and results of research works carried out in RAFAKO, Silesian Technical University in Katowice and Welding Institute in Gliwice within the framework of COST 522 program concerning the influence of simulation of element temperature operating conditions on Chaгpy V notch toughness, HV10 hardness, microstructure of simulated HAZ's, assessment of steel weldability, strength properties. The welded joints structure stability and HAZ after stress relief annealing and after ageing - simulation of element operating conditions are presented in the form of graphs and prints of microstructures.
Proceedings Papers
AM-EPRI2010, Advances in Materials Technology for Fossil Power Plants: Proceedings from the Sixth International Conference, 762-786, August 31–September 3, 2010,
... Reactor Program (LMFBR). ORNL together with Combustion Engineering, initiated a program to develop a superior grade of 9Cr-1Mo steel which called for 512ºC (970ºF) service temperature and toughness of 54J (40 Ft-lbs) at room temperature. This was achieved through the controlled additions of vanadium (V...
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View Papertitled, P(T)91 Steel-A Review of Current Code and Fabrication Practices
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Advanced chromium-molybdenum-vanadium steels 9CrMoV [P(T)91] have seen extensive global adoption across power, petrochemical, and other industrial sectors over the past decade, driven by the demand for materials with superior high-temperature properties to improve efficiency. Experience with P(T)91 base metals and weldments has revealed that these steels require substantially more attention than the commonly used P(T)22 grade and similar materials. This presentation examines Grade 91's various design code requirements across power, petroleum, and nuclear industries, focusing on fabrication and welding considerations. The discussion covers critical material properties and heat treatment parameters, including the significance of maintaining proper preheat and interpass temperatures, while highlighting the risks associated with interrupted heating cycles and improper postweld heat treatment. The paper also addresses factors influencing the use, development, and procurement of Modified Grade 91 welding consumables for heavy wall applications, and explores the subtle technical differences between North American and European approaches to production and utilization, ultimately emphasizing the considerable care required during joining processes to ensure acceptable long-term properties.
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