Study on Effects of Non-Isothermal Condition and Strain Holding on Environmentally Assisted Fatigue in PWR Primary Water Environment

2016 ◽  
Author(s):  
Seiji Asada ◽  
Yuichi Fukuta ◽  
Kawaljit Ahluwalia ◽  
David Steininger
Keyword(s):  
Fatigue Behavior ◽  
Hold Time ◽  
Water Environment ◽  
Isothermal Condition ◽  
Austenitic Stainless Steels ◽  
Strain Range ◽  
Fatigue Tests ◽  
Test Material ◽  
Strain Rate Change ◽  
Primary Water

To understand the fatigue behavior of austenitic stainless steels in a simulated PWR primary water environment, the patterns were studied. Austenitic stainless steel Type 316 plate was used as the test material. Regarding non-isothermal testing: isothermal and non-isothermal fatigue tests were carried out for several patterns of temperature change and strain rate change. Typically, fatigue lives for non-isothermal tests with an out-of-phase strain change pattern were longer than those for isothermal tests. Regarding strain holding testing: multiple groups of strain range cycles were separated by a long hold time and several test cases were carried out. Testing shows there is little difference in fatigue life for strain holding tests with high strain amplitude.

Study on Effects of Non-Isothermal Condition and Strain Holding on Environmentally Assisted Fatigue in PWR Primary Water Environment (Step III)

2019 ◽  
Author(s):  
Daiki Takagoshi ◽  
Seiji Asada ◽  
Yuichirou Nomura ◽  
Gary Stevens ◽  
Kawaljit Ahluwalia
Keyword(s):  
Water Environment ◽  
Isothermal Condition ◽  
Austenitic Stainless Steels ◽  
Fatigue Tests ◽  
Small Scale ◽  
Pressurized Water ◽  
Transient Conditions ◽  
Isothermal Conditions ◽  
Primary Water ◽  
Isothermal Test

Abstract To further understand the environmentally assisted fatigue (EAF) behavior of Type 316 austenitic stainless steels (SS) in a pressurized water reactor (PWR) primary water environment, the influence of non-isothermal transient conditions was investigated using hollow, small-scale fatigue specimens. In our previous study (Step I: PVP2016-63798), isothermal and non-isothermal EAF tests were performed. The non-isothermal transient conditions for the fatigue tests investigated transients that consisted of both in-phase and out-of-phase temperature and strain variations. The result of this test series showed longer fatigue lives than those predicted using the modified rate approach and the EAF multiplier (Fen) presented in the draft of NUREG/CR-6909, Revision 1. In our follow-on study (Step II: PVP2017-66233), one extra non-isothermal test was performed and application of the Weighted Stress Intensity Factor (K) Rate (WKR) method was discussed. In the latest Step III testing, an extra non-isothermal test with periodic beachmarking has been performed. This paper discusses, based on the completion of all EAF tests performed in Steps I – III of this project, the effects of non-isothermal conditions and recommendations which are made for treatment of non-isothermal conditions in EAF assessments.

Study on Effects of Non-Isothermal Condition and Strain Holding on Environmentally Assisted Fatigue in PWR Primary Water Environment: Step II

2017 ◽  
Author(s):  
Seiji Asada ◽  
Daiki Takagoshi ◽  
Yuichi Fukuta ◽  
Kazuya Tsutsumi ◽  
Kawaljit Ahluwalia ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Fatigue Behavior ◽  
Compressive Strain ◽  
Water Environment ◽  
Isothermal Condition ◽  
Fatigue Tests ◽  
Transient Condition ◽  
Isothermal Fatigue ◽  
Primary Water

In order to understand the fatigue behavior in PWR primary water environment, the influence of non-isothermal transient condition was investigated for austenitic stainless steel 316SS. In our previous study (PVP2016-63798), isothermal and non-isothermal environmentally assisted fatigue tests were performed. The fatigue life of the non-isothermal fatigue test consisted of a high temperature and tensile strain rate transient, a portion of which occurred in the compressive strain region of the strain cycle. The result of this test showed longer life than the predicted fatigue life estimated by the modified rate approach and Fen factor as presented in NUREG/CR-6909 Rev.1. In this paper, the reason why the fatigue test showed longer fatigue life is studied. Crack growth analysis was performed to understand the effect of the environment on fatigue life. Additionally, application of the Weighted K Rate (WKR) method described in reference (PVP2016-63497) was applied to a series of tests. This approach showed good agreement on fatigue life for a number of different waveforms for isothermal tests. The methodology was applied to some of this investigation’s non-isothermal fatigue tests and shown to be an improvement that justifies further investigation.

Creep-Fatigue Properties of the Candidate Materials of 700°C-USC Boiler

2007 ◽  
Author(s):  
Keiji Kubushiro ◽  
Hiroki Yoshizawa ◽  
Takuya Itou ◽  
Hirokatsu Nakagawa
Keyword(s):  
Hold Time ◽  
Strain Range ◽  
Small Strain ◽  
Fatigue Tests ◽  
Holding Time ◽  
Experimental Results ◽  
Fatigue Properties ◽  
Alloy 617 ◽  
Creep Fatigue ◽  
Cycles To Failure

Creep-fatigue properties of candidate materials of 700°C-USC boiler are investigated. The candidate materials are Alloy 230, Alloy 263, Alloy 617 and HR6W. Creep-fatigue tests were conducted at 700°C and the effect of both strain range and hold time were studied. Experimental results showed that at 1.0% strain range, cycles to failure with 60 min strain holding is about 10% of that without strain holding, but at 0.7% strain range, cycles to failure with 60 min strain holding decreases down to about 1% of without strain holding. It appears that cycles to failure is decreased by increasing strain holding time at all tested strain ranges, and the effect of holding time is emphasized at small strain range. These phenomena depend on the kind of alloys.

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.

Effects of Primary Water Environment on the Thermal Aged Cast Austenitic Stainless Steels

2015 ◽  
Author(s):  
Yuichi Fukuta ◽  
Hiroshi Kanasaki ◽  
Takahisa Yamane
Keyword(s):  
Fracture Toughness ◽  
Stainless Steels ◽  
Water Environment ◽  
Prediction Method ◽  
Austenitic Stainless Steels ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Ferrite Content ◽  
Pressurized Water ◽  
Primary Water

This report summarizes the results of a scoping fracture toughness tests at high and low temperature for thermally aged cast austenitic stainless steels (CASSs) in a pressurized water reactor (PWR) environment. CF8M (ferrite content = 10.1%, 18.9%) and CF8 (ferrite content = 10.5%) were thermally aged up to 5,000 hours at 465°C. Tensile tests, Charpy impact tests and fracture toughness tests were conducted in air at 325°C and 50°C. Fracture toughness tests were also performed in simulated PWR primary water. Although the effect of 325°C and 50°C in simulated PWR primary water and dissolved hydrogen on the fracture toughness (JIc and J-Δa relationship) were slightly observed, fracture toughness was greater than that predicted by the thermally aged fracture toughness prediction method (Hyperbolic-Time-Temperature-Toughness (H3T) model).

scholarly journals Development of a Water Environment Fatigue Design Curve for Austenitic Stainless Steels

2003 ◽  
Author(s):  
Thomas R. Leax
Keyword(s):  
Stainless Steels ◽  
Fatigue Behavior ◽  
Water Environment ◽  
Austenitic Stainless Steels ◽  
Fatigue Curve ◽  
Light Water Reactor ◽  
Design Curve ◽  
Fatigue Design ◽  
American Society ◽  
Design Factors

Technical support is provided for a fatigue curve that could potentially be incorporated into Section III of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code. This fatigue curve conservatively accounts for the effects of light water reactor environments on the fatigue behavior of austenitic stainless steels. This paper presents the data, statistical methods, and basis for the design factors appropriate for Code applications. A discussion of the assumptions and methods used in design curve development is presented.

A Multi-Station Rolling/Sliding Tribotester for Knee Bearing Materials

2004 ◽  
Vol 126 (2) ◽  
pp. 380-385 ◽  
Author(s):  
Douglas W. Van Citters ◽  
Francis E. Kennedy ◽  
John H. Currier ◽  
John P. Collier ◽  
Thomas D. Nichols
Keyword(s):  
Material Properties ◽  
Normal Load ◽  
Fatigue Behavior ◽  
Water Environment ◽  
Fatigue Tests ◽  
Test Environment ◽  
Normal Contact ◽  
Bearing Materials ◽  
Number Of Cycles

Total joint replacements traditionally employ ultra high molecular weight polyethylene (UHMWPE) as a bearing material due to its desirable material properties and biocompatibility. Failure of these polyethylene bearings can lead to expensive and risky revision surgery, necessitating a better understanding of UHMWPE’s tribological properties. A six-station rolling/sliding machine was developed to study the behavior of accelerated-aged UHMWPE in cylinder-on-cylinder contact. The normal load and sliding/rolling ratio in the oscillatory contacts can be controlled separately for each test station, as can the liquid test environment. Fatigue tests were run on the machine with UHMWPE versus cobalt-chrome cylinders in a distilled water environment at normal contact pressures of approximately 20 MPa. All specimens failed by subsurface cracking during tribotesting on the machine, and the failures were similar to those that occur in-vivo. The fatigue behavior of the polymer was analyzed to determine its relationship to oxidation and stress state in the rolling/sliding cylinder. At the 20 MPa test load, the number of cycles to fatigue failure by subsurface cracking was inversely proportional to the oxidation level. Analysis of the stress levels through the bulk of the polyethylene specimens and their relationship to the material properties provide insight as to why cracks initiate and propagate subsurface.

INCEFA-PLUS Project: Review of the Test Programme

2020 ◽  
Author(s):  
Matthias Bruchhausen ◽  
Alec McLennan ◽  
Roman Cicero ◽  
Caitlin Huotilainen ◽  
Kevin Mottershead ◽  
...  
Keyword(s):  
Stress Testing ◽  
Hold Time ◽  
Water Environment ◽  
Fatigue Tests ◽  
Light Water Reactor ◽  
Test Programme ◽  
Biaxial Fatigue ◽  
Experiment Method ◽  
Mean Strain ◽  
Single Batch

Abstract The European Project INCEFA-PLUS (INcreasing Safety in NPPs by Covering gaps in Environmental Fatigue Assessment) characterizes environmentally assisted fatigue of stainless steels in light water reactor environments. The project includes a major test programme during which more than 200 fatigue tests have been carried out in different laboratories across Europe. The test campaign was structured in three successive phases with slightly different foci. All testing programmes were optimized by means of the Design of Experiment method. The majority of the tests were carried out on a single batch of 304L which were complemented by tests on different batches of 304L and on X6 CrNiTi 18 10, a Ti stabilized steel used in VVERs. The influences of mean strain, surface roughness and hold time on fatigue life in air and water environment at a given environmental fatigue correction factor Fen were investigated. Besides the main test campaign, additional activities on the effects of mean stress, testing at reduced Fen, and different applications of hold time as well as biaxial fatigue tests have been carried out. The paper is part of a special session for the dissemination of the project results. It summarizes the tests performed during the project and provides the basis for the project conclusions in a different paper in the same session.

Influence of Hold-Time and Temperature on the Low-Cycle Fatigue of Incoloy 800

1972 ◽  
Vol 94 (3) ◽  
pp. 930-934 ◽  
Author(s):  
C. E. Jaske ◽  
H. Mindlin ◽  
J. S. Perrin
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Compressive Strain ◽  
Hold Time ◽  
Strain Range ◽  
Cyclic Fatigue ◽  
Cycle Fatigue ◽  
Incoloy 800 ◽  
Strain Cycling

A study has been conducted to determine the low-cycle fatigue behavior of solution-annealed Incoloy 800 bar at temperatures from 800–1400 deg F. The experimental work included evaluation of specimens under both continuous, completely reversed strain cycling and under strain cycling with hold time periods at the strain limits. At 1000, 1200, and 1400 deg F, it was found that 10-min hold-times at the tensile strain limit during every cycle significantly reduced the cyclic fatigue life compared to continuous cycling. However, there was little reduction in cyclic fatigue life when 10-min hold-times were introduced at the compressive strain limits or at both the tensile and compressive limits. The ratio of hold-time cyclic fatigue life to no-hold-time cyclic fatigue life decreased as the length of hold time increased (at constant total strain range) and as the magnitude of strain range decreased (at constant hold-time length).

Low Cycle Fatigue of Commercial Piping Steels in a BWR Primary Water Environment

1981 ◽  
Vol 103 (1) ◽  
pp. 15-25 ◽  
Author(s):  
D. A. Hale ◽  
S. A. Wilson ◽  
J. W. Kass ◽  
E. Kiss
Keyword(s):  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Water Environment ◽  
Experimental Program ◽  
Cycle Fatigue ◽  
Inconel 600 ◽  
Fatigue Design ◽  
High Pressure High Temperature ◽  
Primary Water ◽  
Oxygenated Water

This report summarizes results of a comprehensive experimental program on the low cycle fatigue behavior of commercial grade piping steels in a high-pressure, high-temperature, oxygenated water environment. A total of 110 specimens of special design were tested in a boiling water reactor (BWR) primary water environment (500°F, 1040 psig (or 260° C, ∼ 7 MPa). Four piping steels, in several different metallurgical conditions, were involved (Types-304 and –304L stainless steels, Inconel-600 and A-516 carbon steel). Companion tests, employing the same types of specimens, were conducted in 500° F (260° C) air. The results of this work confirm the adequacy of the current ASME Section III fatigue design curves to account for the effect of a BWR primary water environment on the low cycle fatigue behavior of the four materials tested.

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