High-strain fatigue of stainless-steel cylinders: Experimental results and their application to pressure-vessel design

1967 ◽  
Vol 2 (4) ◽  
pp. 290-297 ◽  
Author(s):  
C Ruiz
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Static Pressure ◽  
Elastic Stress ◽  
High Strain ◽  
Pressure Vessels ◽  
Supplementary Information ◽  
Test Results ◽  
Stress Range ◽  
Fatigue Design

Thin cylindrical specimens, plain and with deep axial grooves, have been tested under pulsating pressure and under static pressure with cyclic axial straining. The test results, together with some supplementary information from other authors, show that Langer's method, based on an elastic-stress analysis, is applicable to the fatigue design of pressure vessels. Design curves for the establishment of the acceptable elastic-stress range corresponding to a given fatigue life are proposed. Attention is drawn to the limitations of Langer's method.

Very thin torispherical pressure vessel ends under internal pressure: Test procedure and typical results

1981 ◽  
Vol 16 (3) ◽  
pp. 171-186 ◽  
Author(s):  
P Stanley ◽  
T D Campbell
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Elastic Stress ◽  
Test Procedure ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Test Installation ◽  
Stress Indices ◽  
Pressure Test ◽  
Strain Data

Very thin cylindrical pressure vessels with torispherical end-closures have been tested under internal pressure until buckles developed in the knuckles of the ends. These were prototype vessels in an austenitic stainless steel. The preparation of the ends and the closed test vessels is outlined, and the instrumentation, test installation, and test procedure are described. Results are given and discussed for three typical ends (diameters 54, 81, and 108in.; thickness to diameter ratios 0.00237, 0.00158, and 0.00119). These include measured thickness and curvature distributions, strain data and the derived elastic stress indices, and pole deflection measurements. Some details of the observed time-dependent plasticity (or ‘cold creep’) are given. Details of two types of buckle that developed eventually in the vessel ends are also reported.

Effects of Surface Finish and Loading Conditions on the Low Cycle Fatigue Behavior of Austenitic Stainless Steel in PWR Environment: Comparison of LCF Test Results With NUREG/CR-6909 Life Estimations

2008 ◽  
Author(s):  
Jean Alain Le Duff ◽  
Andre´ Lefranc¸ois ◽  
Jean Philippe Vernot
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Environmental Effects ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Complex Signal ◽  
Loading Conditions ◽  
Test Results ◽  
Cycle Fatigue

During mid 2006, ANL issued a NUREG/CR-6909 [2] report that is now applicable in The US for evaluations of PWR environmental effects in the fatigue analysis of new reactor components. In order to assess the conservativeness of the application of this NUREG report, low cycle fatigue (LCF) tests were performed by AREVA NP on austenitic stainless steel specimens in a PWR environment. The selected material exhibits in an air environment a fatigue behavior consistent with the ANL reference “air” mean curve. Tests were performed for two various loading conditions: for fully reverse triangular signal (for comparison purpose with tests performed by other laboratories with same loading conditions) and complex signal, simulating strain variation for actual typical PWR thermal transients. Two surface finish conditions were tested: polished and ground. The paper presents on one side the comparison of environmental penalty factors (Fen = Nair,RT/Nwater) as observed experimentally with the ANL formulation (considering the strain integral method for complex loading), and, on the other hand, the actual fatigue life of the specimen with the fatigue life predicted through the NUREG/CR-6909 application. Low Cycle Fatigue test results obtained on austenitic stainless steel specimens in PWR environment with triangle waveforms at constant low strain rates gives Fen penalty factors close to those estimated using the ANL formulation (NUREG report 6909). On the contrary, it was observed that constant amplitude LCF test results obtained under complex signal reproducing an actual sequence of a cold and hot thermal shock exhibits significantly lower environmental effects when compared to the Fen penalty factor estimated on the basis of the ANL formulations. It appears that the application of the NUREG/CR-6909 [2] in conjunction with the Fen model proposed by ANL for austenitic stainless steel provides excessive margins whereas the current ASME approach seems sufficient to cover significant environmental effect for components.

An Empirical Life Prediction Method of Cold-Stretched Austenitic Stainless Steel

2016 ◽  
Vol 853 ◽  
pp. 67-71
Author(s):  
Yu Han ◽  
Ke Sheng Wang
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Prediction Model ◽  
Test Data ◽  
Life Prediction ◽  
Pressure Vessels ◽  
Fatigue Life Prediction ◽  
Life Prediction Model

With the purpose of long-cycle safe operation of cold stretched austenitic stainless steel pressure vessels so as to achieve unification of economy and safety, prediction of fatigue life of S31603 austenitic stainless steel at high temperature is systematic studied. Based on the Hull-Rimmer cavity theory, a fatigue life prediction model applicable to stress controlled is developed. Fatigue test is carried out on the solution annealed and cold stretched S31603 steel at high temperature and corresponding test data is obtained. The fatigue life of the solution annealed and cold stretched materials is predicted by the model and the prediction results are in good agreement with the experimental results. On this basis, the life prediction model coupled with the strain level of cold stretching is further established. Compared with the test data, the prediction results is found to be very satisfactory with an error band less than ±1.5 times. The fatigue life prediction model suitable for stress control at high temperature is simple in form and has a clear and obvious physical significance which points out a new way to predict fatigue life of metal materials.

Paris Fatigue Life Modeling of Pressure Vessel Service Simulation Tests

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
John H. Underwood ◽  
John J. Keating ◽  
Edward Troiano ◽  
Gregory N. Vigilante
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Pressure Vessel ◽  
Base Alloy ◽  
Pressure Vessels ◽  
Full Scale ◽  
Test Results ◽  
X Ray Diffraction ◽  
Life Model ◽  
Nickel Base

Results from four groups of full-scale pressure vessel service simulation tests are described and analyzed using Paris fatigue life modeling. The objective is to determine how the vessel and initial crack configurations and applied and residual stresses control the as-tested fatigue life of the vessel. The tube inner radii are in the 40–80 mm range; wall thickness varies from 6 to 80 mm; materials are ASTM A723 pressure vessel steel and IN718 nickel-base alloy; applied internal pressure varies from 90 to 700 MPa. The Paris constant, C, and exponent, m, that describe the fatigue crack propagation rate versus stress intensity factor range for the various vessel materials, were measured as part of the investigation. Extensive, previously published fatigue life results from baseline A723 pressure vessels with well characterized autofrettage residual stresses and C and m values are used to demonstrate that a Paris fatigue life model gives a good description of the measured life. The same model is then used to determine the variables with predominant control over life in three types of pressure vessel for which less information and tests results are available. A design life for pressure vessels is calculated for a specified very low probability of fatigue failure using the log(N)-normal distribution statistics often used for fatigue of structures. The results of the work showed: (i) X-ray diffraction measurements of through-wall autofrettage residual stresses are in excellent agreement with prior neutron diffraction measurements from a baseline autofrettaged A723 pressure vessel; these verified autofrettage residual stresses then provide critical input to the baseline Paris life modeling; (ii) comparison of the various full-scale fatigue test results with results from the Paris fatigue life model shows close agreement when autofrettage residual stresses are incorporated into models; (iii) model results for A723 steel vessels with yield strength reduced from the initial 1400 MPa value and degree of autofrettage increased from the initial 40% value indicates a significantly improved resistance to brittle failure with no loss of fatigue life; (iv] comparison of model fatigue life results for IN718 nickel-base alloy vessels with their full-scale test results is improved when near-bore residual stresses measured by X-ray diffraction are included in the model calculations.

Fatigue Analysis of Stainless Steel Overlap Joining Panel Partially Penetrated by Laser Welding

2008 ◽  
Vol 580-582 ◽  
pp. 515-518 ◽  
Author(s):  
Kyoung Don Lee ◽  
Ki Young Park ◽  
Kwang Il Ho
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Laser Welding ◽  
Welding Process ◽  
Fatigue Tests ◽  
Test Results ◽  
Bead Width ◽  
Local Stresses ◽  
Theoretical Stress ◽  
Different Thickness

Experiment, finite element method, and theoretical analysis were performed to understand the fatigue phenomena of stainless steel overlap joining panels of different thickness partially penetrated by Nd:YAG Laser welding. The fatigue life curves are obtained through fatigue tests with various levels of applied load. The fatigue life is related with parameters such as thickness of plates, bead width, gap size, and penetration depth through experiment. To understand the fatigue test results, the effects of local stresses around a weld bead are calculated by FEM and theoretical stress analysis as a guide to the laser welding process control.

Fatigue Testing and Life Estimates of Welded Flat Head Pressure Vessel Joints

2006 ◽  
Author(s):  
Chris Hinnant
Keyword(s):  
Stainless Steel ◽  
Fatigue Testing ◽  
Design Method ◽  
Plate Thickness ◽  
Pressure Vessels ◽  
Thin Plates ◽  
Fatigue Design ◽  
Single Side ◽  
Section Viii ◽  
Division 2

Experimental results for the cyclic pressure fatigue of several pressure vessels with flat heads are reported and compared against various fatigue design methods. The geometry is based on a welded joint presented in a recent paper by Kalnins, Bergsten, and Rana (2005). Weld designs between the head and shell include full penetration welds completed from a single side and both sides of the shell. Unique characteristics of this test include thin plate design, a large D/t ratio, and a low membrane-to-bending ratio. These are aspects of flat head geometries which have not been widely reported in the literature. Allowable fatigue cycles for ASME Section VIII, Division 2, IIW, PD 5500, EN 13445, API 579, and the Master S-N method (proposed for the ASME Section VIII, Division 2 rewrite project) are presented. Results show that several of these design method produce non-conservative fatigue life predictions. In addition, the fatigue results demonstrate that size effects and plate thickness effects have diminishing influence for thin plates failing at less than 100,000 cycles. Finally, the fatigue strength of stainless steel is compared to carbon steel and the lack of a unified approach to stainless steel fatigue design is discussed.

scholarly journals Fatigue behavior of 316L austenitic stainless steel in air and LWR environment with and without mean stress

2018 ◽  
Vol 165 ◽  
pp. 03012 ◽  
Author(s):  
Wen Chen ◽  
Philippe Spätig ◽  
Hans-Peter Seifert
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Fatigue Limit ◽  
Fatigue Behavior ◽  
Cyclic Hardening ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Test Results ◽  
316L Austenitic Stainless Steel

The fatigue life design curves in nuclear codes are generally derived from uniaxial straincontrolled fatigue test results. Evidently, the test conditions are very different from the actual components loading context, which involves much more complex thermo-mechanical loading including mean stress, static load holding time and variation in water chemistry, etc. In this work, the mean stress and environmental effects on fatigue life of 316L austenitic stainless steel in air and light water reactor (LWR) environment were studied using hollow fatigue specimens and testing under load-controlled condition. Both positive (+50 MPa) and negative (-20 MPa) mean stresses showed beneficial effect on fatigue life in LWR environment and in air. This is tentatively attributed to mean stress enhanced cyclic hardening, which leads to smaller strain response at the same loading force. -20 MPa mean stress was found to increase fatigue limit, whereas the effect of +50 MPa mean stress on fatigue limit is still unclear. The preliminary results illustrate that the environmental reduction of fatigue life is amplified in load-controlled fatigue tests with tensile mean stress.

Experimental Data, Numerical Fit and Fatigue Life Calculations Relating to the Bauschinger Effect in High Strength Armament Steels

2003 ◽  
Vol 125 (3) ◽  
pp. 330-334 ◽  
Author(s):  
Edward Troiano ◽  
Anthony P. Parker ◽  
John Underwood ◽  
Charles Mossey
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Bauschinger Effect ◽  
High Strength Steels ◽  
High Strength ◽  
Strength Reduction ◽  
Plastic Strains ◽  
Test Results ◽  
Effect Factor ◽  
Modulus Reduction

The uniaxial Bauschinger effect has been evaluated in several high strength steels being considered for armament application. The steels investigated include ASTM A723 (1130 and 1330 MPa), PH 13-8 Mo stainless steel (1380 MPa), PH 13-8 Mo super tough stainless steel (1355 MPa), and HY 180 (1180MPa). Tests were conducted at plastic strains up to 3.5%. Results of testing show a progressive decrease in Bauschinger effect up to plastic strains of approximately 1% (for all materials investigated), after which there is little further decrease in the Bauschinger effect. Several key features were discovered during testing. First, all of the materials tested exhibited a changing modulus, where the elastic modulus on unloading after tensile plastic straining is consistently lower than that observed in the original loading of the specimens. The amount of modulus reduction is dependent upon the material tested, and larger reductions are observed with increasing amounts of tensile plastic strain. Prior work by Milligan reported Bauschinger effect factor β for a modified 4340 steel (old vintage A723 steel), which compares well with the present work. However, his results failed to mention any observations about a modulus reduction. The second observation was the expected strength reduction where a reduced compressive strength is observed as a result of prior tensile plastic straining. Numerical curve fits used to calculate residual stresses, which take into account both the modulus reduction and strength reduction are presented for all materials. Fatigue life calculations, utilizing the numerical curve fits, show good agreement with full size A723 laboratory fatigue test results.

Strain Waveform Effects for Low Cycle Fatigue in Simulated PWR Water

2017 ◽  
Author(s):  
Tommi Seppänen ◽  
Jouni Alhainen ◽  
Esko Arilahti ◽  
Jussi Solin
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Reference Value ◽  
Steel Specimen ◽  
Feedback Signal ◽  
Test Results ◽  
Testing Facility ◽  
Reference Curves

In order to perform design code (ASME III, RCC-M, JSME) compatible direct strain-controlled tests in simulated PWR water, a unique environmental fatigue testing facility was previously developed. Pneumatic bellows are used to generate strain in the stainless steel specimen mid-section, while eddy current based measurement is used as a feedback signal. The NUREG/CR-6909 report gathered a large database of test results and proposed environmental reduction factors (Fen) to account for a reduction in fatigue life in simulated LWR environment when comparing to a reference value in air. The database was composed of non-stabilized stainless steels tested using methods which are not directly comparable to those used in air to define the reference curves. Applicability of the stainless steel Fen factors has already been challenged in previous PVP papers (PVP2013-97500, PVP2014-28465, PVP2016-63294). Results in this paper continue to show this trend of lower experimental Fen factors compared to predictions made by the NUREG report. Dual strain rate tests were performed, specifically focusing on the effect of strain waveform shape on fatigue life. Similarly to last year’s results (PVP2016-63294) a distinct effect of strain waveform, presently inadequately accounted for in Fen predictions, was observed.

scholarly journals Influence of Friction Stir Processing on Mechanical Behavior of 2507 SDSS

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 369 ◽  
Author(s):  
Hafiz M. Abubaker ◽  
Necar Merah ◽  
Fadi A. Al-Badour ◽  
Jafar Albinmousa ◽  
Ahmad A. Sorour
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Fatigue Life ◽  
Duplex Stainless Steel ◽  
Friction Stir Processing ◽  
Base Material ◽  
Pressure Vessels ◽  
Friction Stir

Duplex stainless steel (DSS) is used for desalination equipment, pressure vessels, marine applications, offshore applications, and in oil/gas plants where a highly corrosive environment is present. Super duplex stainless steel (SDSS) 2507 has excellent mechanical properties, such as high strength, high toughness, high fatigue life, and high corrosion resistance. Friction stir processing (FSP) is used to refine the grain structure of the processed region such that properties like strength, hardness, fracture toughness, fatigue life, and corrosion resistance are enhanced. In this paper, an optimized friction stir process of 2507 SDSS is carried out to refine the microstructure of the material in order to improve its mechanical properties. Microstructure analysis revealed that grains were refined from a size of around 160 µm in the base material to 2–30 µm in the processed zone. This grain size reduction resulted in improved strength, hardness, and fracture toughness of the material by up to 14%, 11%, and 12%, respectively. However, FSP has reduced the fracture strain by about 30%.

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