Magnetic Barkhausen Noise Technique for Early Stage Fatigue Prediction in Martensitic Stainless-Steel Samples (invited)

2021 ◽  
pp. 1-18
Author(s):  
Zi Li ◽  
Bharath Basti Shenoy ◽  
L. Udpa ◽  
Yiming Deng
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Power Plants ◽  
Early Stage ◽  
Fatigue Cracks ◽  
Turbine Blades ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise ◽  
Operating Cycle ◽  
Microstructure Changes

Abstract Martensitic grade stainless steel is generally used to manufacture steam turbine blades in power plants. The material degradation of those turbine blades, due to fatigue, will induce unexpected equipment damage. Fatigue cracks, too small to be detected, can grow severely in the next operating cycle and may cause failure before the next inspection opportunity. Therefore, a nondestructive electromagnetic technique, which is sensitive to microstructure changes in the material, is needed to provide a means to estimate the specimen’s fatigue life. To tackle these challenges, this paper presents a novel Magnetic Barkhausen noise (MBN) technique for garnering information relating to the material microstructure changes under test. The MBN signals are analyzed in time as well as frequency domain to infer material information that are influenced by the samples’ mate- rial state. Principal Component Analysis (PCA) is applied to reduce the dimensionality of feature data and extract higher order features. Afterwards, Probabilistic Neural Network (PNN) classifies the sample based on the percentage fatigue life to discover the most correlated MBN features to indicate the remaining fatigue life. Furthermore, one criticism of MBN is its poor repeatability and stability, therefore, Analysis of Variance (ANOVA) is carried out to analyze the uncertainty associated with MBN measurements. The feasibility of MBN technique is investigated in detecting early stage fatigue, which is associated with plastic deformation in ferromagnetic metallic structures. Experimental results demonstrate that the Magnetic Barkhausen Noise technique is a promising candidate for characterizing.

Characterization of microstructures in 17-4-PH stainless steel by magnetic Barkhausen noise analysis

1993 ◽  
Vol 26 (3) ◽  
pp. 141-148 ◽  
Author(s):  
D.K. Bhattacharya ◽  
T. Jayakumar ◽  
V. Moorthy ◽  
S. Vaidyanathan ◽  
Baldev Raj
Keyword(s):  
Stainless Steel ◽  
Noise Analysis ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise

A Synthetical Numerical Model for Evaluating the Reliability of Turbine Blade

2002 ◽  
Author(s):  
Yonghui Xie ◽  
Di Zhang
Keyword(s):  
Fatigue Life ◽  
Numerical Model ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Power Plants ◽  
Dynamic Stress ◽  
Turbine Blades ◽  
Dynamic Stress Analysis ◽  
Steam Turbine Blades ◽  
Blade Failure

Reliability of turbines is very important for power plants, and the most common blade failure normally result from forced vibration which lead to fatigue failure of blades. In this study, a synthetical numerical model has been developed to obtain more precise evaluation of the reliability of blades. At first, the model used to analyze the dynamic stress of steam turbine blades is investigated, base on the results of dynamic stress analysis, a model to evaluate the fatigue life of turbine blade has been developed, many factors such as manufacturing technology of blades and erosion operating environment are considered to get more accurate results for the fatigue life prediction of blades. At last, a 323 mm blade in a 75MW steam turbine is analyzed by the model developed in this paper, it is shown clearly that the model can provide some significant data to evaluate the reliability of blade.

Finite-Element Analysis of Crack Growth in Austenitic Stainless Steel Under Equibiaxial Loading

2018 ◽  
Author(s):  
H. Dhahri ◽  
C. Gourdin ◽  
H. Maitournam
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Crack Growth ◽  
Power Plants ◽  
Austenitic Steels ◽  
Biaxial Test ◽  
New Device ◽  
Penalty Factor ◽  
Mean Strain

The lifetime extension of the nuclear power plants is considered as an energy challenge worldwide. That is why, the risk analysis and the study of various effects of different factors that could potentially represent a hazard to a safe long term operation are necessary. These structures, often of great dimensions, are subjected during their life to complex loading combining varying mechanical loads, multiaxial, with non-zero mean values associated with temperature fluctuations and also PWR environment. Based on more recent fatigue data (including tests at 300°C in air and PWR environment, etc...), some international codes (RCC-M [2], ASME and others [3][4][5]) have introduced a modification of the austenitic stainless steels fatigue curve combined with a calculation of an environmental penalty factor, namely Fen, which has to be multiplied by the usual fatigue usage factor [6]. Unfortunately, experimental data on this issue are rare. In order to obtain fatigue strength data under structural loading, biaxial test means with and without PWR environment were developed at LISN in collaboration with EDF and AREVA [6]. Two kinds of fatigue device have been developed. Within the same specimen geometry, structural loads can be applied in varying only the PWR environment. The first device (FABIME2) is devoted to study the effect of biaxiality and mean strain/stress on the fatigue life [9]. A second and new device called FABIME2e is for the study of the environmental effect. With these new experimental results, the PWR environment effect on the fatigue life of stainless austenitic steels will be quantified accurately on semi-structure specimen. This device combines the structural effect like equi-biaxiality and mean strain and the environmental penalty effect with the use of PWR environment during the fatigue tests. The aim of this paper is to present the numerical interpretation of the results obtained with these two devices “FABIME2” and “FABIME2e”. Two important aspects will be addressed. The first concerns the mechanical behavior of austenitic stainless steel and the capabilities of the numerical model to reproduce the hardening of the material. And the second concerns the study of the crack growth during the equibiaxial fatigue test.

scholarly journals Parameters influencing the low-cycle fatigue life of materials in pressure water reactor nuclear power plants / Parametry ovlivòující únavové chování materiálù pro tlakovodní jaderné reaktory v režimu nízkocyklové únavy

2015 ◽  
Vol 59 (3) ◽  
pp. 91-98
Author(s):  
V. Šefl
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Carbon Steel ◽  
Austenitic Stainless Steel ◽  
Literature Review ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue

Abstract In this literature review we identify and quantify the parameters influencing the low-cycle fatigue life of materials commonly used in nuclear power plants. The parameters are divided into several groups and individually described. The main groups are material properties, mode of cycling and environment parameters. The groups are further divided by the material type - some parameters influence only certain kind of material, e.g. sulfur content may decreases fatigue life of carbon steel, but is not relevant for austenitic stainless steel; austenitic stainless steel is more sensitive to concentration of dissolved oxygen in the environment compared to the carbon steel. The combination of parameters i.e. conjoint action of several detrimental parameters is discussed. It is also noted that for certain parameters to decrease fatigue life, it is necessary for other parameter to reach certain threshold value. Two different approaches have been suggested in literature to describe this complex problem - the Fen factor and development of new design fatigue curves. The threshold values and examples of commonly used relationships for calculation of fatigue lives are included. This work is valuable because it provides the reader with long-term literature review with focus on real effect of environmental parameters on fatigue life of nuclear power plant materials.

Evaluation of Fatigue Damage in LWR Water With and Without Threshold and Moderation Factor

2003 ◽  
Author(s):  
Makoto Higuchi ◽  
Kazuya Tsutsumi ◽  
Katsumi Sakaguchi
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Power Plants ◽  
Light Water Reactor ◽  
Low Alloy Steels ◽  
Light Water ◽  
Water Reactor ◽  
Fatigue Data ◽  
Fatigue Life Reduction

During the past twenty years, the fatigue initiation life of LWR structural materials, carbon, low alloy and stainless steels has been shown to decrease remarkably in the simulated LWR (light water reactor) coolant environments. Several models for evaluating the effects of environment on fatigue life reduction have been developed based on published environmental fatigue data. Initially, based on Japanese fatigue data, Higuchi and Iida proposed a model for evaluating such effects quantitatively for carbon and low alloy steels in 1991. Thereafter, Chopra et al. proposed other models for carbon, low alloy and stainless steels by adding American fatigue data in 1993. Mehta developed a new model which features the threshold concept and moderation factor in Chopra’s model in 1995. All these models have undergone various revisions. In Japan, the MITI (Ministry of International Trade and Industry) guideline on environmental fatigue life reduction for carbon, low alloy and stainless steels was issued in September 2000, for evaluating of aged light water reactor power plants. The MITI guideline provide equations for calculations applicable only to stainless steel in PWR water and consequently Higuchi et al. proposed in 2002 a revised model for stainless steel which incorporates new equations for evaluation of environmental fatigue reduction in BWR water. The paper compares the latest versions of these models and discusses the conservativeness of the models by comparison of the models with available test data.

scholarly journals Effect of Temperature and Hold Time of Induction Brazing on Microstructure and Shear Strength of Martensitic Stainless Steel Joints

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1586 ◽  
Author(s):  
Yunxia Chen ◽  
Haichao Cui
Keyword(s):  
Stainless Steel ◽  
Shear Strength ◽  
Power Plants ◽  
Filler Metal ◽  
Martensitic Stainless Steel ◽  
Braze Alloy ◽  
Hold Time ◽  
Turbine Blades ◽  
Element Distribution ◽  
Effect Of Temperature

1Cr12Mo martensitic stainless steel is widely used for intermediate and low-pressure steam turbine blades in fossil-fuel power plants. A nickel-based filler metal (SFA-5.8 BNi-2) was used to braze 1Cr12Mo in an Ar atmosphere. The influence of brazing temperature and hold time on the joints was studied. Microstructure of the joints brazed, element distribution and shear stress were evaluated at different brazing temperatures, ranging from 1050 °C to 1120 °C, with holding times of 10 s, 30 s, 50 s and 90 s. The results show that brazing joints mainly consist of the matrix of the braze alloy, the precipitation, and the diffusion affected zone. The filler metal elements diffusion is more active with increased brazing temperature and prolonged hold time. The shear strength of the brazed joints is greater than 250 MPa when the brazing temperature is 1080 °C and the hold time is 30 s.

scholarly journals Use of Magnetic Barkhausen Noise (MBN) to Follow Up the Formation of Sigma Phase in Saf2205 (UNS S31803) Duplex Stainless Steel

2016 ◽  
Vol 19 (5) ◽  
pp. 1008-1016 ◽  
Author(s):  
Edgar Apaza Huallpa ◽  
Eduardo Franco de Monlevade ◽  
Julio Capó Sánchez ◽  
Manuel Alberteris Campos ◽  
Linilson Padovese ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Sigma Phase ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise

Fatigue Crack Initiation of 304L Stainless Steel in Simulated PWR Primary Environment: Relative Effect of Strain Rate

2012 ◽  
Author(s):  
Nicolas Huin ◽  
Kazuya Tsutsumi ◽  
Laurent Legras ◽  
Thierry Couvant ◽  
Dominique Loisnard ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Initiation ◽  
Strain Rate ◽  
Early Stage ◽  
Laboratory Data ◽  
Fatigue Crack Initiation ◽  
304L Stainless Steel ◽  
Pressurized Water

The French Regulatory Commission insisted on a survey justifying the assumed mechanical behavior of components exposed to Pressurized Water Reactor (PWR) water under cyclic loading without taking into account its effect. In the US and Japan, the fatigue life correlation factors, so called Fen, are formulated and standardized on the basis of laboratory data to take into account the effect on fatigue life evaluation. However, the current fatigue codification, suffers from a lack of understanding of environmental effects on the fatigue lives of stainless steels in simulated hydrogenated PWR environments. Samples tested in a recent study were analyzed to highlight the strain rate effect (within a range 0.4%/s to 0.004%/s) at the early stage of fatigue life in PWR primary environment for a 304L stainless steel. The deleterious effect of PWR primary environment on fatigue crack initiation was observed with a quantitative microscopic approach. Multi scale observations of oxide morphology and microstructure were carried out from common optical microscopy using recent technologies such as 3D oxide reconstruction, and DualBeam observations.

Sign in / Sign up

Export Citation Format

Share Document