Influence of temperature and microstructure on creep-fatigue of Alloy 800H

1988 ◽  
Vol 6 (4) ◽  
pp. 181-186 ◽  
Author(s):  
J.O. Nilsson ◽  
R. Sandström
Keyword(s):  
Alloy 800H ◽  
Influence Of Temperature ◽  
Creep Fatigue

A Unified Constitutive Model With Optimized Parameters for Base and Diffusion Bonded Alloy 800H

2020 ◽  
Author(s):  
Heramb P. Mahajan ◽  
Tasnim Hassan
Keyword(s):  
Elevated Temperature ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Constitutive Model ◽  
Nuclear Power ◽  
Parameter Determination ◽  
Alloy 800H ◽  
Inelastic Analysis ◽  
Creep Fatigue ◽  
Plant Components

Abstract Current ASME Section III, Division 5 code provides elastic, simplified inelastic and inelastic analysis options for designing nuclear power plant components for elevated temperature service. These analyses methods may fail to capture the complex creep-fatigue response and damage accumulation in materials at elevated temperatures. Hence, for analysis and design of the nuclear power plant components at elevated temperature, a full inelastic analysis that can simulate creep-fatigue responses may be needed. Existing ASME code neither provides guidelines for using full inelastic analysis nor recommends the type of constitutive model to be used. Hence, a unified rate-dependent constitutive model incorporating a damage parameter will be developed, and its parameters for base metal will be determined. In addition, a full inelastic analysis methodology using this model to analyze the creep-fatigue performance of components for nuclear power applications will be developed. Base metal 800H (BM800H) data are collected from literature to determine constitutive material model parameters. The parameter determination methodology for a constitutive model is discussed. The optimized parameter set for BM 800H at different temperatures will be presented in the paper. Recommendations are provided on the constitutive model selection and its parameter determination techniques. In the future, this work will be continued for diffusion bonded Alloy 800H (DB800H) material, and obtained parameters will be compared.

Evaluation of Creep-Fatigue Damage for Hot Gas Duct Structure of the NHDD Plant

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Hyeong-Yeon Lee ◽  
Kee-Nam Song ◽  
Yong-Wan Kim
Keyword(s):  
High Temperature ◽  
Fatigue Damage ◽  
Inlet Temperature ◽  
Temperature Structure ◽  
Alloy 800H ◽  
Alloy 617 ◽  
Draft Code ◽  
Hot Gas ◽  
Creep Fatigue ◽  
Technical Issues

Evaluation of creep-fatigue damage has been carried out for the hot gas duct (HGD) structure in the nuclear hydrogen development and demonstration (NHDD) plant. The core outlet and inlet temperature of the NHDD plant are 950°C and 490°C, respectively. Case studies on high temperature design codes of the draft code case for Alloy 617, ASME boiler and pressure vessel code section III subsection NH (ASME-NH), and RCC-MR were carried out for the inner tube of the HGD for the candidate materials of Alloy 617 and Alloy 800H. Technical issues in application of the draft code case to a high temperature structure are discussed for the Alloy 617 material. Code comparison between the ASME-NH and RCC-MR for Alloy 800H has been carried out. The candidate material of the outer pressure boundary (cross vessel) of the HGD is Mod.9Cr-1Mo steel. The damage evaluation, according to the ASME-NH and RCC-MR for the cross vessel of Mod.9Cr-1Mo steel, has been conducted and their results were compared.

Evaluation of Creep-Fatigue Damage for Hot Gas Duct Structure of the NHDD Plant

2009 ◽  
Author(s):  
Hyeong-Yeon Lee ◽  
Kee-Nam Song ◽  
Yong-Wan Kim
Keyword(s):  
High Temperature ◽  
Fatigue Damage ◽  
Inlet Temperature ◽  
Temperature Structure ◽  
Alloy 800H ◽  
Alloy 617 ◽  
Draft Code ◽  
Hot Gas ◽  
Creep Fatigue ◽  
Technical Issues

Evaluation of creep-fatigue damage has been carried out for the HGD (hot gas duct) structure in the NHDD (Nuclear Hydrogen Development and Demonstration) plant. The core outlet and inlet temperature of the NHDD plant are 950°C and 490°C, respectively. Case studies on high temperature design codes of the draft Code Case for Alloy 617, ASME-NH and RCC-MR were carried out for the inner tube of the HGD for the candidate materials of Alloy 617 and Alloy 800H. Technical issues in application of the draft Code Case to a high temperature structure are discussed for Alloy 617 material. Code comparison between the ASME-NH and RCC-MR for Alloy 800H has been carried out. The candidate material of the outer pressure boundary (cross vessel) of the HGD is Mod.9Cr-1Mo steel. The damage evaluation according to the ASME-NH and RCC-MR for the cross vessel of Mod.9Cr-1Mo steel has been conducted and their results were compared.

Mechanical and Microstructural Characterization of Diffusion Bonded 800H

2020 ◽  
Author(s):  
Heramb P. Mahajan ◽  
Mohamed Elbakhshwan ◽  
Bruce C. Beihoff ◽  
Tasnim Hassan
Keyword(s):  
Mechanical Property ◽  
Base Metal ◽  
Microstructure Evolution ◽  
Diffusion Bonding ◽  
Elevated Temperatures ◽  
Bonding Process ◽  
Atomic Diffusion ◽  
Alloy 800H ◽  
Tensile Fatigue ◽  
Creep Fatigue

Abstract Compact heat exchangers have high compactness and efficiency, which is achieved by joining a stack of chemically etched channeled plates through diffusion bonding. In the diffusion bonding process, compressive stress is applied on plates at elevated temperatures for a specified period. These conditions lead to atomic diffusion, which results in the joining of all plates into a monolithic block. The diffusion bonding temperatures are above recrystallization temperatures, which changes the mechanical and microstructural properties of the bonded metal. Hence, diffusion bonded material needs mechanical and microstructural property evaluation. In this study, Alloy 800H is selected to study the influence of the diffusion bonding process on mechanical and microstructure properties of base metal. A series of tensile, fatigue, creep, and creep-fatigue experiments are conducted on base metal 800H (BM 800H) and diffusion bonded 800H (DB 800H) to explore the mechanical properties. Microstructure evolution during diffusion bonding is studied and presented in the paper. The mechanical and microstructural observations indicated ductile fracture at room temperature and brittle failure with bond delamination at elevated temperatures. The microstructure evolution during diffusion bonding is studied through tensile, fatigue, creep and creep-fatigue tests, and the implied root causes for the mechanical property changes are investigated. Efforts are made to correlate the microstructure change with mechanical property change in DB 800H.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

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