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A Review & Assessment of Current Operating Conditions Allowable Stresses in ASME Section III Subsection NH

Description: The current operating condition allowable stresses provided in ASME Section III, Subsection NH were reviewed for consistency with the criteria used to establish the stress allowables and with the allowable stresses provided in ASME Section II, Part D. It was found that the S{sub o} values in ASME III-NH were consistent with the S values in ASME IID for the five materials of interest. However, it was found that 0.80 S{sub r} was less than S{sub o} for some temperatures for four of the materials. Only values for alloy 800H appeared to be consistent with the criteria on which S{sub o} values are established. With the intent of undertaking a more detailed evaluation of issues related to the allowable stresses in ASME III-NH, the availabilities of databases for the five materials were reviewed and augmented databases were assembled.
Date: December 14, 2009
Creator: Swindeman, R. W.
Partner: UNT Libraries Government Documents Department

Development of Advanced Corrosion-Resistant Fe-Cr-Ni Austenitic Stainless Steel Alloy with Improved High-Temperature Strength and Creep-Resistance

Description: In February of 1999, a Cooperative Research and Development Agreement (CRADA) was undertaken between Oak Ridge National Laboratory (ORNL) and Special Metals Corporation - Huntington Alloys (formerly INCO Alloys International, Inc.) to develop a modified wrought austenitic stainless alloy with considerably more strength and corrosion resistance than alloy 800H or 800HT, but with otherwise similar engineering and application characteristics. Alloy 800H and related alloys have extensive use in coal flue gas environments, as well as for tubing or structural components in chemical and petrochemical applications. The main concept of the project was make small, deliberate elemental microalloying additions to this Fe-based alloy to produce, with proper processing, fine stable carbide dispersions for enhanced high temperature creep-strength and rupture resistance, with similar or better oxidation/corrosion resistance. The project began with alloy 803, a Fe-25Cr-35NiTi,Nb alloy recently developed by INCO, as the base alloy for modification. Smaller commercial developmental alloy heats were produced by Special Metal. At the end of the project, three rounds of alloy development had produced a modified 803 alloy with significantly better creep resistance above 815 C (1500 C) than standard alloy 803 in the solution-annealed (SA) condition. The new upgraded 803 alloy also had the potential for a processing boost in that creep resistance for certain kinds of manufactured components that was not found in the standard alloy. The upgraded 803 alloy showed similar or slightly better oxidation and corrosion resistance relative to standard 803. Creep strength and oxidation/corrosion resistance of the upgraded 803 alloy were significantly better than found in alloy 800 H, as originally intended. The CRADA was terminated in February 2003. A contributing factor was Special Metals Corporation being in Chapter 11 Bankruptcy. Additional testing, further commercial scale-up, and any potential invention disclosures were not pursued.
Date: June 15, 2001
Creator: Maziasz, P.J. & Swindeman, R.W.
Partner: UNT Libraries Government Documents Department

Simplified Design Criteria for Very High Temperature Applications in Generation IV Reactors

Description: The goal of this activity is to provide simplified criteria which can be used in rapid feasibility assessments of the structural viability of very high temperature components in conceptual and early preliminary design phases for Generation IV reactors. The current criteria in ASME Code Section III, Subsection NH, hereafter referred to as NH, (and Code Case N-201 for core support structures) are difficult and require a complex deconstruction of finite element analysis results for their implementation. Further, and most important, times, temperatures and some materials of interest to the very high temperature Generation IV components are not covered by the current provisions of NH. Future revisions to NH are anticipated that will address very high temperature Generation IV components and materials requirements but, until that occurs interim guidance is required for design activities to proceed. These simplified criteria are for design guidance and are not necessarily in rigorous compliance with NH methodology. Rather, the objective is for criteria which address the early design needs of very high temperature Generation IV components and materials. The intent is to provide simplified but not overly conservative design methods. When more rigorous criteria and methods are incorporated in NH, the degree of conservatism should obviously be reduced. These criteria are based on currently available information. Although engineering judgments have been made in the formulation of these criteria they are not intended to require additional development or testing prior to implementation as a tool for use in conceptual and early preliminary design. Appendices are provided herein that contain useful information. The simplified methods were developed specifically with Alloy 617 in mind; however, they could be applied for the same intended purpose for other materials such as 9Cr-1Mo, Alloy 800H, etc. However, supporting design curves, stress allowables, and isochronous curves may/were not available at this time ...
Date: December 15, 2004
Creator: McGreevy, TE
Partner: UNT Libraries Government Documents Department

Evaluation of HAZ liquation cracking susceptibility and HAZ softening behavior in modified 800H

Description: A modified 800H alloy, developed at Oak Ridge National Laboratory (ORNL), is one of the candidate materials designed for high temperature applications. Extensive mechanical and corrosion investigations have been completed and it has been proven that modified 800 has excellent high temperature mechanical and metallurgical behavior. Weldability studies of modified 800H are being carried out at the University of Tennessee, Knoxville. A series of modified 800H alloys and two similar commercial high temperature materials (310Ta and HR3C) were used to conduct this investigation. A preliminary weldability evaluation has been accomplished and the major part of the results (HAZ liquation cracking resistance and HAZ softening behavior in modified 800H) is addressed in this report. The basic conclusion of this investigation is that modified 800H material possesses good resistance to HAZ liquation cracking especially with a grain size control (thermo-mechanical treatment). The information from this study is important to the further modification of the material in order to extend its applications.
Date: November 20, 1992
Creator: Lundin, C. D. & Qiao, C. Y. P.
Partner: UNT Libraries Government Documents Department

Development of materials resistant to metal dusting degradation.

Description: Metal dusting corrosion has been a serious problem in the petroleum and petrochemical industries, such as reforming and syngas production systems. This form of deterioration has led to worldwide material loss for 50 years. For the past three years, we have studied the mechanism of metal dusting for Fe- and Ni-base alloys. In this report, we present a correlation between the weight loss and depth of pits that form in Ni-base alloys. Nickel-base alloys were also tested at 1 and 14.8 atm (210 psi), in a high carbon activity environment. Higher system pressure was found to accelerate corrosion in most Ni-base alloys. To reduce testing time, a pre-pitting method was developed. Mechanical scratches on the alloy surface led to fast metal dusting corrosion. We have also developed preliminary data on the performance of weldments of several Ni-base alloys in a metal dusting environment. Finally, Alloy 800 tubes and plates used in a reformer plant were examined by scanning electron microscopy, energy dispersive X-ray, and Raman spectroscopy. The oxide scale on the surface of the Alloy 800 primarily consists of Fe{sub 1+x}Cr{sub 2-X}O{sub 4} spinel phase with high Fe content. Carbon can diffuse through this oxide scale. It was discovered that the growth of metal dusting pits could be stopped by means of a slightly oxidized alloy surface. This leads to a new way to solve metal dusting problem.
Date: April 24, 2006
Creator: Natesan, K. & Zeng, Z.
Partner: UNT Libraries Government Documents Department

Thermal stability of high temperature structural alloys

Description: High temperature structural alloys were evaluated for suitability for long term operation at elevated temperatures. The effect of elevated temperature exposure on the microstructure and mechanical properties of a number of alloys was characterized. Fe-based alloys (330 stainless steel, 800H, and mechanically alloyed MA 956), and Ni-based alloys (Hastelloy X, Haynes 230, Alloy 718, and mechanically alloyed MA 758) were evaluated for room temperature tensile and impact toughness properties after exposure at 750 C for 10,000 hours. Of the Fe-based alloys evaluated, 330 stainless steel and 800H showed secondary carbide (M{sub 23}C{sub 6}) precipitation and a corresponding reduction in ductility and toughness as compared to the as-received condition. Within the group of Ni-based alloys tested, Alloy 718 showed the most dramatic structure change as it formed delta phase during 10,000 hours of exposure at 750 C with significant reductions in strength, ductility, and toughness. Haynes 230 and Hastelloy X showed significant M{sub 23}C{sub 6} carbide precipitation and a resulting reduction in ductility and toughness. Haynes 230 was also evaluated after 10,000 hours of exposure at 850, 950, and 1050 C. For the 750--950 C exposures the M{sub 23}C{sub 6} carbides in Haynes 230 coarsened. This resulted in large reductions in impact strength and ductility for the 750, 850 and 950 C specimens. The 1050 C exposure specimens showed the resolution of M{sub 23}C{sub 6} secondary carbides, and mechanical properties similar to the as-received solution annealed condition.
Date: March 1, 1999
Creator: Jordan, C.E.; Rasefske, R.K. & Castagna, A.
Partner: UNT Libraries Government Documents Department

Effect of oxidation/sulfidation on creep behavior of alloy 800

Description: Metallic components within or immediately adjacent to gasifiers, such as gas distributors, thermowells, transfer lines, and cyclones, are subjected to particularly severe conditions of temperature, pressure, and hostile multicomponent gas environments. In addition, metallic heat exchangers/waste-heat boilers that are resistant to sulfidation, corrosion, and erosion in low- and medium-Btu gas environments are essential components in large-scale gasification schemes in both dry-ash and slagging-type gasifiers. Components of these schemes must generally be resistant to corrosion, erosion, and high-temperature creep. Refractory linings are conventionally employed to mitigate corrosion and erosion; in some cases, internal cooling has been considered a way to avoid problems associated with the interaction of high-temperature creep and fatigue. Contrary to the codes and standards that exist for vessel and piping design, no guidance in the form of a code or standard exists for internal and long-life external vessel components, especially for service in corrosive-erosive environments at elevated temperatures. The purpose of the present work is to examine the high-temperature creep behavior of Alloy 800, a high-chromium alloy that is widely used in coal conversion systems, after exposure to oxygen and oxygen/sulfur mixed-gas environments over a wide temperature range. In addition, data on the creep behavior of the alloy under various pretreatment and test exposure conditions are used to establish performance envelopes for the alloy in fossil energy applications.
Date: May 1, 1995
Creator: Natesan, K.
Partner: UNT Libraries Government Documents Department

Metals technology development plan

Description: This document presents the plan for the metals technology development required to support the design of the MHTGR within the US National Gas-Cooled Reactor Program. Besides descriptions of the required technology development, cost estimates, and schedules, the plan also includes the associated design functions and design requirements.
Date: March 1, 1987
Creator: Betts, W.S.
Partner: UNT Libraries Government Documents Department

TEM Examination of Advanced Alloys Irradiated in ATR

Description: Successful development of materials is critical to the deployment of advanced nuclear power systems. Irradiation studies of candidate materials play a vital role for better understanding materials performance under various irradiation environments of advanced system designs. In many cases, new classes of materials have to be investigated to meet the requirements of these advanced systems. For applications in the temperature range of 500 800ºC which is relevant to the fast neutron spectrum burner reactors for the Global Nuclear Energy Partnership (GNEP) program, oxide dispersion strengthened (ODS) and ferritic martensitic steels (e.g., MA957 and others) are candidates for advanced cladding materials. In the low temperature regions of the core (<600ºC), alloy 800H, HCM12A (also called T 122) and HT 9 have been considered.
Date: September 1, 2007
Creator: Jian Gan, PhD
Partner: UNT Libraries Government Documents Department

Development of Advanced Corrosion-Resistant Fe-Cr-Ni Austenitic Stainless Steel Alloy with Improved High Temperature Strenth and Creep-Resistance

Description: In February of 1999, a Cooperative Research and Development Agreement (CRADA) was undertaken between Oak Ridge National Laboratory (ORNL) and Special Metals Corporation-Huntington Alloys (formerly INCO Alloys International, Inc.) to develop a modified wrought austenitic stainless alloy with considerably more strength and corrosion resistance than alloy 800H or 800HT, but with otherwise similar engineering and application characteristics. Alloy 800H and related alloys have extensive use in coal flue gas environments, as well as for tubing or structural components in chemical and petrochemical applications. The main concept of the project was make small, deliberate elemental microalloying additions to this Fe-based alloy to produce, with proper processing, fine stable carbide dispersions for enhanced high temperature creep-strength and rupture resistance, with similar or better oxidation/corrosion resistance. The project began with alloy 803, a Fe-25Cr-35NiTi,Nb alloy recently developed by INCO, as the base alloy for modification. Smaller commercial developmental alloy heats were produced by Special Metals. At the end of the project, three rounds of alloy development had produced a modified 803 alloy with significantly better creep resistance above 815EC (1500EC) than standard alloy 803 in the solution-annealed (SA) condition. The new upgraded 803 alloy also had the potential for a processing boost in that creep resistance for certain kinds of manufactured components that was not found in the standard alloy. The upgraded 803 alloy showed similar or slightly better oxidation and corrosion resistance relative to standard 803. Creep strength and oxidation/corrosion resistance of the upgraded 803 alloy were significantly better than found in alloy 800H, as originally intended. The CRADA was terminated in February 2003. A contributing factor was Special Metals Corporation being in Chapter 11 Bankruptcy. Additional testing, further commercial scale-up, and any potential invention disclosures were not pursued. One objective of this project was to improve the high temperature creep resistance ...
Date: September 30, 2004
Creator: Maziasz, PJ
Partner: UNT Libraries Government Documents Department

Correlation of substructure with mechanical properties of plastically deformed AISI 304 and 316 stainless steel. Progress report, January 1--March 31, 1973

Description: The recovery behavior of cold-worked AISI -316 stainless steel was studied using hot hardness. Hot hardness and substructure of AISI 304 stainless steel were correlated with tensile data, and transmission electron microscopy was carried out. The substructure of Incoloy 800 tensile tested at 800 to 1400 deg F was studied. (DLC)
Date: June 15, 1973
Creator: Moteff, J.
Partner: UNT Libraries Government Documents Department

Characterization of Elevated Temperature Properties of Heat Exchanger and Steam Generator Alloys

Description: The Next Generation Nuclear Plant project is considering Alloy 800H and Alloy 617 for steam generator and intermediate heat exchangers. It is envisioned that a steam generator would operate with reactor outlet temperatures from 750 to 800°C, while an intermediate heat exchanger for primary to secondary helium would operate up to an outlet temperature of 950°C. Although both alloys are of interest due in part to their technical maturity, a number of specific properties require further characterization for design of nuclear components. Strain rate sensitivity of both alloys has been characterized and is found to be significant above 600°C. Both alloys also exhibit dynamic strain aging, characterized by serrated flow, over a wide range of temperatures and strain rates. In general dynamic strain aging is observed to begin at higher temperatures and serrated flow persists to higher temperatures in Alloy 617 compared to Alloy 800H. Dynamic strain aging is a concern for these materials since it is observed to result in reduced ductility for many solid solution alloys. The role of dynamic strain aging in the creep-fatigue behavior of Alloy 617 at temperatures of 800°C and above has also been examined in detail. Serrated flow is found to persist in cyclic stress-strain curves up to nearly the cycle to failure in some temperature and strain regimes. Results of those experiments and implications for creep-fatigue testing protocols will be described.
Date: October 1, 2010
Creator: Wright, J.K.; Carroll, L.J.; Benz, J.K.; Simpson, J.A.; Wright, R.N.; Lloyd, W.R. et al.
Partner: UNT Libraries Government Documents Department

Preliminary issues associated with the next generation nuclear plant intermediate heat exchanger design.

Description: The Next Generation Nuclear Plant (NGNP), which is an advanced high temperature gas reactor (HTGR) concept with emphasis on production of both electricity and hydrogen, involves helium as the coolant and a closed-cycle gas turbine for power generation with a core outlet/gas turbine inlet temperature of 900-1000 C. In the indirect cycle system, an intermediate heat exchanger is used to transfer the heat from primary helium from the core to the secondary fluid, which can be helium, nitrogen/helium mixture, or a molten salt. The system concept for the vary high temperature reactor (VHTR) can be a reactor based on the prismatic block of the GT-MHR developed by a consortium led by General Atomics in the U.S. or based on the PBMR design developed by ESKOM of South Africa and British Nuclear Fuels of U.K. This report has made a preliminary assessment on the issues pertaining to the intermediate heat exchanger (IHX) for the NGNP. Two IHX designs namely, shell and tube and compact heat exchangers were considered in the assessment. Printed circuit heat exchanger, among various compact heat exchanger (HX) designs, was selected for the analysis. Irrespective of the design, the material considerations for the construction of the HX are essentially similar, except may be in the fabrication of the units. As a result, we have reviewed in detail the available information on material property data relevant for the construction of HX and made a preliminary assessment of several relevant factors to make a judicious selection of the material for the IHX. The assessment included four primary candidate alloys namely, Alloy 617 (UNS N06617), Alloy 230 (UNS N06230), Alloy 800H (UNS N08810), and Alloy X (UNS N06002) for the IHX. Some of the factors addressed in this report are the tensile, creep, fatigue, creep fatigue, toughness properties for the candidate ...
Date: April 5, 2007
Creator: Natesan, K.; Moisseytsev, A.; Majumdar, S. & Shankar, P. S.
Partner: UNT Libraries Government Documents Department

High performance steam cogeneration (proof-of-concept phases). Phase 2, HRSG 500-hour test report: Final report

Description: Recent advances in small once-through Alloy 800 steam generators, improved materials technology, and application of small industrial gas turbine technology to steam turbine cogeneration offers the potential to make a step increase in steam temperature from around 1000{degree}F, where industry has been for almost fifty years, to 1500{degree}F. In small cogeneration systems, it is economically practical to introduce new technology and make a step change in temperature where it may not be possible (given the regulatory environment and economic risk) for a major change in steam temperature to be introduced in the hundreds of megawatt size of an electric utility. Increasing the peak steam temperature in a steam turbine cycle allows more work to be extracted or electrical power to be generated from a given quantity of heat input. Figure 1 plots steam efficiency as a function of superheat steam temperature and pressure for a turbine-back pressure of 166 psia. This figure clearly shows that increasing the steam conditions from the typical current practice of 900{degree}F and 900 psia to 1500{degree}F and 1500 psia will increase the steam cycle efficiency by 53%. The combination of higher cycle efficiency with an advanced high efficiency steam turbine design provides a substantial increase in turbine output power for a given steam flowrate. The output of this advanced high temperature steam turbine is approximately twice that of a current industrial practive turbine for the same turbine flowrate as seen in Figure 2.
Date: December 1, 1992
Creator: Campbell, A. H.
Partner: UNT Libraries Government Documents Department

Investigation of joining techniques for advanced austenitic alloys

Description: Modified Alloys 316 and 800H, designed for high temperature service, have been developed at Oak Ridge National Laboratory. Assessment of the weldability of the advanced austenitic alloys has been conducted at the University of Tennessee. Four aspects of weldability of the advanced austenitic alloys were included in the investigation.
Date: May 1, 1991
Creator: Lundin, C. D.; Qiao, C. Y. P.; Kikuchi, Y.; Shi, C. & Gill, T. P. S.
Partner: UNT Libraries Government Documents Department

Interactions between creep and corrosion in Alloy 800

Description: Metallic components within or immediately adjacent to gasifiers, such as gas distributors, thermowells, transfer lines, and cyclones, are subjected to severe of temperature, pressure, and hostile multicomponent gas environments. Metallic heat exchangers/waste-heat boilers resistant to sulfidation, corrosion. and erosion in low- and medium-Btu gas environments are essential components in large-scale gasification schemes, in both dry ash and slogging type gasifiers. Components, in general. must be resistant to corrosion, erosion, and high-temperature creep. A substantial data base is needed on the mechanical properties of materials exposed to complex gas environments to provide a more viable basis for establishing long-term reliability of components. This work examines high-temperature creep of Alloy 800, a high-chromium alloy widely used in coal conversion systems, after exposure to oxygen and oxygen/sulfur mixed-gas environments over a wide temperature range. In addition, the data on the creep behavior of the alloy under various pretreatment and test-exposure conditions are used to establish performance envelopes for the alloy for service in fossil energy applications.
Date: April 1, 1994
Creator: Natesan, K.
Partner: UNT Libraries Government Documents Department