Development of creep-dominant creep-fatigue testing for Alloy 617

2016 ◽  
Author(s):  
Fraaz Tahir ◽  
Yongming Liu
Keyword(s):  
Fatigue Testing ◽  
Alloy 617 ◽  
Creep Fatigue

scholarly journals Determination of the Creep-Fatigue Interaction Diagram for Alloy 617

2016 ◽  
Author(s):  
J. K. Wright ◽  
L. J. Carroll ◽  
T.-L. Sham ◽  
N. J. Lybeck ◽  
R. N. Wright
Keyword(s):  
Fatigue Testing ◽  
Hold Time ◽  
Strain Range ◽  
Fatigue Tests ◽  
Alloy 617 ◽  
Interaction Diagram ◽  
Creep Fatigue ◽  
Intermediate Heat Exchanger ◽  
Cycles To Failure

Alloy 617 is the leading candidate material for an intermediate heat exchanger for the very high temperature reactor (VHTR). As part of evaluating the behavior of this material in the expected service conditions, creep–fatigue testing was performed. The cycles to failure decreased compared to fatigue values when a hold time was added at peak tensile strain. At 850°C, increasing the tensile hold duration continued to degrade the creep–fatigue resistance, at least to the investigated strain–controlled hold time of up to 60 minutes at the 0.3% strain range and 240 minutes at the 1.0% strain range. At 950°C, the creep–fatigue cycles to failure are not further reduced with increasing hold duration, indicating saturation occurs at relatively short hold times. The creep and fatigue damage fractions have been calculated and plotted on a creep–fatigue interaction D–diagram. Test data from creep–fatigue tests at 800 and 1000°C on an additional heat of Alloy 617 are also plotted on the D–diagram.

Low Cycle Fatigue and Creep-Fatigue Behavior of Alloy 617 at High Temperature

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Celine Cabet ◽  
Laura Carroll ◽  
Richard Wright
Keyword(s):  
High Temperature ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Dominant Role ◽  
Hold Time ◽  
Outlet Temperature ◽  
Cycle Fatigue ◽  
Alloy 617 ◽  
Creep Fatigue

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the very high temperature nuclear reactor (VHTR), expected to have an outlet temperature as high as 950 °C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanisms and failure life. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950 °C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle fatigue specimens exhibited transgranular cracking. Intergranular cracking was observed in the creep-fatigue specimens and the addition of a hold time at peak tensile strain degraded the cycle life. This suggests that creep-fatigue interaction occurs and that the environment may be partially responsible for accelerating failure.

High-Temperature Creep-Fatigue of Alloy 617 Base Metal and Weldments

2007 ◽  
Author(s):  
Terry C. Totemeier
Keyword(s):  
Weld Metal ◽  
Base Metal ◽  
Fatigue Testing ◽  
Hold Time ◽  
Fatigue Cracking ◽  
Rolled Plate ◽  
Alloy 617 ◽  
Hold Period ◽  
Creep Fatigue ◽  
Metal Creep

Creep-fatigue testing of nickel alloy 617 base metal and fusion weldments was performed at temperatures of 800 and 1000°C in air in support of ASME BPV Sec III code qualification of alloy 617 for the Next-Generation Nuclear Plant. Cyclic loading was performed in strain control with a trapezoidal waveform and was fully reversed. Creep was introduced into the fatigue cycle by a hold period at maximum tensile strain which varied from 18 to 9000 seconds. Base metal specimens were machined from 20 mm thick rolled plate; weldment specimens were machined from GTAW butt-welded plate such that the loading direction was oriented transverse to the welding direction. Weld metal, heat-affected zone, and base metal were present in the reduced section of weldment specimens. Creep-fatigue lives decreased with increasing hold time for both base metal and weldments; lives of weldments were reduced relative to those of base metal. Creep-fatigue cracking in weldment specimens initiated in the weld metal.

scholarly journals The Role of Environment on High Temperature Creep-Fatigue Behavior of Alloy 617

2010 ◽  
Author(s):  
Laura Carroll ◽  
Celine Cabet ◽  
Richard Wright
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Dominant Role ◽  
Hold Time ◽  
Outlet Temperature ◽  
Alloy 617 ◽  
Creep Fatigue

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the Very High Temperature Nuclear Reactor (VHTR), expected to have an outlet temperature as high as 950°C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanism/s and failure life. Furthermore, previous work on corrosion of nickel base alloys in impure helium has suggested that this environment is far from inert with respect to Alloy 617. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950°C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle and creep-fatigue specimens exhibited intergranular cracking, but did not show evidence of grain boundary cavitation. Despite the absence of grain boundary cavitation to accelerate crack propagation, the addition of a hold time at peak tensile strain was detrimental to cycle life. This suggests that creep-fatigue interaction may occur by a different mechanism or that the environment may be partially responsible for accelerating failure.

scholarly journals Creep and Creep-Fatigue of Alloy 617 Weldments

2014 ◽  
Author(s):  
Jill K. Wright ◽  
Laura J. Carroll ◽  
Richard N. Wright
Keyword(s):  
Alloy 617 ◽  
Creep Fatigue

scholarly journals Draft Rules for Alloy 617 Creep-Fatigue Design using an EPP+SMT Approach

2021 ◽  
Author(s):  
B. Barua ◽  
M. Messner ◽  
Y. Wang ◽  
T. Sham ◽  
R. Jetter
Keyword(s):  
Alloy 617 ◽  
Fatigue Design ◽  
Creep Fatigue

A Viscoplastic Model for Alloy 617 for Use With the ASME Section III, Division 5 Design by Inelastic Analysis Rules

2021 ◽  
Author(s):  
M. C. Messner ◽  
T.-L. Sham
Keyword(s):  
High Temperature ◽  
Alloy 617 ◽  
Element Analysis ◽  
Material Models ◽  
Experimental Database ◽  
Viscoplastic Model ◽  
Analysis And Design ◽  
Inelastic Analysis ◽  
Wide Range ◽  
Creep Fatigue

Abstract The rules for the design of high temperature reactor components in Section III, Division 5, Subsection HB, Subpart B (HBB) of the ASME Boiler and Pressure Vessel Code contain two options for evaluating the deformation-controlled design limits on strain accumulation and creep-fatigue: design by elastic analysis and design by inelastic analysis. Of these options design by inelastic analysis tends to be less overconservative and produce more efficient designs. However, the HBB currently does not provide approved material models for use with the inelastic analysis rules, limiting their widespread use. A nonmandatory appendix has been developed to provide general guidance on appropriate material models and provide reference material models suitable for use with the design by inelastic analysis approach. This paper describes a viscoplastic model for Alloy 617 suitable for use with the HBB rules proposed for incorporation into the new appendix. The model represents the high temperature creep, creep-fatigue, and tensile response of Alloy 617 and accurately accounts for rate sensitivity across a wide range of temperatures. The focus in developing the model was on capturing key features of material deformation required for accurately executing the HBB rules and on developing a relatively simple model form that can be implemented in commercial finite element analysis software. The paper validates the model against an extensive experimental database collected as part of the Alloy 617 Code qualification effort as well as against specialized experimental tests examining the effect of elastic follow up on stress relaxation and creep deformation in the material.

scholarly journals Microstructure evolution of alloy 709 during static-aging and creep-fatigue testing

2021 ◽  
Vol 801 ◽  
pp. 140361
Author(s):  
T.D. Porter ◽  
Z. Wang ◽  
E.P. Gilbert ◽  
M.J. Kaufman ◽  
R.N. Wright ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Fatigue Testing ◽  
Creep Fatigue

An Evaluation of Creep-Fatigue Damage for the Prototype Process Heat Exchanger of the NHDD Plant

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Hyeong-Yeon Lee ◽  
Kee-Nam Song ◽  
Yong-Wan Kim ◽  
Sung-Deok Hong ◽  
Hong-Yune Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Fatigue Damage ◽  
Inlet Temperature ◽  
Alloy 617 ◽  
Element Analysis ◽  
Creep Fatigue ◽  
Process Heat ◽  
Very High

A process heat exchanger (PHE) transfers the heat generated from a nuclear reactor to a sulfur-iodine hydrogen production system in the Nuclear Hydrogen Development and Demonstration, and was subjected to very high temperature up to 950°C. An evaluation of creep-fatigue damage, for a prototype PHE, has been carried out from finite element analysis with the full three dimensional model of the PHE. The inlet temperature in the primary side of the PHE was 950°C with an internal pressure of 7 MPa, while the inlet temperature in the secondary side of the PHE is 500°C with internal pressure of 4 MPa. The candidate materials of the PHE were Alloy 617 and Hastelloy X. In this study, only the Alloy 617 was considered because the high temperature design code is available only for Alloy 617. Using the full 3D finite element analysis on the PHE model, creep-fatigue damage evaluation at very high temperature was carried out, according to the ASME Draft Code Case for Alloy 617, and technical issues in the Draft Code Case were raised.

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