Low Cycle Fatigue Behavior of Original Ferritic P92 Steel at High Temperature: Experiments and Simulations

2015 ◽  
Author(s):  
Xiaowei Wang ◽  
Jianming Gong ◽  
Yong Jiang ◽  
Yanping Zhao
Keyword(s):  
Plastic Material ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Constant Strain Rate ◽  
Cyclic Softening ◽  
Isotropic Hardening ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
P92 Steel ◽  
Softening Behavior

Low cycle fatigue tests of original ferritic P92 steel at high temperatures and different strain amplitudes were conducted to investigate its cyclic softening behavior and fracture behavior. LCF tests of strain amplitudes ranging from ±0.2% to ±0.8% were performed in fully reversed manner with constant strain rate at 600 °C and 650 °C. In order to represent the different hysteresis stress-strain curves and the cyclic softening behavior of P92 steel, a cyclic plastic material model was used. In the model, improved nonlinear isotropic hardening parameter was proposed to make better simulation of the cyclic softening behavior. Based on the simulated stress-strain hysteresis loops, an energy-based life prediction model was used to predict the low cycle fatigue life. When compared with experimental responses, the simulations and predicted life were found to be quite reasonable. Low cycle fatigue fractography of the P92 steel was also observed, and it was found to be associated with the different strain amplitudes imposed on the specimen, the larger strain amplitude the more amounts of crack initiation sites could be found.

Cyclic Softening Effect on Design Margin of JLF-1 Steel

2013 ◽  
Author(s):  
Huailin Li
Keyword(s):  
Elevated Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cyclic Softening ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Softening Effect ◽  
As Stress ◽  
Supercritical Water Cooled Reactor ◽  
Design Margin

A reduced-activation ferritic/martensitic (RAF/M) steel, JLF-1, is considered as one of the candidate structure material of the fusion reactors and supercritical water-cooled reactor (SCWR). Low cycle fatigue properties of JLF-1 steel at elevated temperature are the design base to provide adequate design margin against postulated mechanism that could experience during its design life, such as stress range, plastic deformation, and cyclic softening etc. However, the reduction in design margin is significant when the cyclic softening happens in cyclic deformation at RT, 673K, 873K. Thus, for the application as the structural materials, it is necessary to evaluate low cycle fatigue behavior and cyclic softening of JLF-1 steel at elevated temperature since those properties of material at elevated temperature are the key issue for design.

High-Temperature Low-Cycle Fatigue Behavior of MarBN at 600 °C

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Richard A. Barrett ◽  
Eimear M. O'Hara ◽  
Padraic E. O'Donoghue ◽  
Sean B. Leen
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Material Model ◽  
Cyclic Softening ◽  
Cyclic Strength ◽  
Cycle Fatigue ◽  
Viscoplastic Material

This paper presents the high-temperature low-cycle fatigue (HTLCF) behavior of a precipitate strengthened 9Cr martensitic steel, MarBN, designed to provide enhanced creep strength and precipitate stability at high temperature. The strain-controlled test program addresses the cyclic effects of strain-rate and strain-range at 600 °C, as well as tensile stress-relaxation response. A recently developed unified cyclic viscoplastic material model is implemented to characterize the complex cyclic and relaxation plasticity response, including cyclic softening and kinematic hardening effects. The measured response is compared to that of P91 steel, a current power plant material, and shows enhanced cyclic strength relative to P91.

Low Cycle Fatigue Behavior of a New Type of Zircaloy Material

2011 ◽  
Vol 80-81 ◽  
pp. 788-791
Author(s):  
Wei Wei Yu ◽  
Fei Xue ◽  
Xin Ming Meng ◽  
Lei Lin
Keyword(s):  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Cycle Fatigue ◽  
Fatigue Lifetime ◽  
Softening Behavior ◽  
New Type

To investigate the property of a new type of Zircaloy material, a low cycle fatigue (LCF) test has been performed at room temperature (RT) and 375°C. Results show that the new alloy generally displays cyclic hardening followed by a continuous softening behavior. Fatigue lifetime curves as a function of strain range imply that the new alloy has a nearly same lifetime than that of Zr-4 at RT, and superior than that at 375°C.

Modeling of Low Cycle Behavior of P92 Steel Based on Cyclic Plasticity Constitutive Equations

2015 ◽  
Vol 750 ◽  
pp. 41-46 ◽  
Author(s):  
Xiao Wei Wang ◽  
Jian Ming Gong ◽  
Yong Jiang ◽  
Yan Ping Zhao ◽  
Ming Hao Yu
Keyword(s):  
High Temperature ◽  
Strain Amplitude ◽  
Model Comparison ◽  
Low Cycle Fatigue ◽  
Cyclic Softening ◽  
Cyclic Plasticity ◽  
P92 Steel ◽  
Softening Behavior ◽  
Steel Material ◽  
Cyclic Plasticity Model

Strain controlled uniaxial low cycle fatigue (LCF) tests of P92 steel were conducted at strain amplitudes of 0.4%, 0.6% and 0.8% in fully reversed manner with strain rate of 1.0×10-3s-1 at high temperature of 650 °C. Cyclic softening behavior was studied and time-independent cyclic plasticity model was used to represent the cyclic mechanical behavior of this steel. Material parameters were determined step by step at higher strain amplitude of 0.8%, experimental data with lower strain amplitude were used to validate the extrapolation of the model. Comparison of the simulated and experimental results shows that the proposed model can give a reasonable prediction of stress-strain hysteresis loop for P92 steel at high temperature.

Comparative Low-Cycle Fatigue Behavior of HAYNES 244 Alloy and Waspaloy

2021 ◽  
Author(s):  
Michael G. Fahrmann
Keyword(s):  
Thermal Loading ◽  
Coefficient Of Thermal Expansion ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Axial Strain ◽  
Fatigue Crack Initiation ◽  
High Strength ◽  
Cyclic Hardening ◽  
Cycle Fatigue ◽  
Softening Behavior

Abstract HAYNES® 244® alloy was chiefly developed to address the need for high-strength, low coefficient of thermal expansion (CTE) alloys for seal rings and cases in advanced gas turbine engines. In addition to these attributes, adequate resistance to low-cycle fatigue (LCF) due to cyclic thermal and mechanical loading during service is critical for such applications. The isothermal LCF performance of commercially produced 0.5” (12.5 mm) thick, fully heat treated plate products of 244 alloy was evaluated by means of axial strain-controlled (R = −1) LCF tests covering total strain ranges up to 1.25 % (without dwells), at temperatures ranging from 800–1400°F (427–760°C). In addition, the comparative LCF performance of Waspaloy, a well-established alloy for turbine cases, was evaluated under selected, nominally identical test conditions. S-N curves were constructed and fitted by the Coffin-Manson equation, allowing the delineation of regimes controlled by the elastic and plastic response of the material. Fracture surfaces were examined in the scanning electron microscope to identify fatigue crack initiation sites and crack propagation modes. Differences between the alloys are discussed in terms of tensile strength and cyclic hardening/softening behavior. Implications for fatigue performance of these alloys under cyclic thermal loading conditions are discussed as well.

Effect of Relative Mean Strain in High-Temperature Low-Cycle Fatigue of a Stainless Steel

1975 ◽  
Vol 97 (4) ◽  
pp. 238-242 ◽  
Author(s):  
Thang Bui-Quoc ◽  
Andre Biron
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Axial Strain ◽  
Constant Strain Rate ◽  
Cycle Fatigue ◽  
Total Strain Range ◽  
The Mean ◽  
Mean Strain

The effect of the relative mean strain in the low-cycle fatigue of a stainless steel (AISI 304) in air at 650°C and at a constant strain rate (4 × 10−3s−1) is studied. Two modes of strain measurement (axial and diametral) were used separately in nonzero mean strain experiments with controlled axial strain in real time. The effect of the relative mean strain on the fatigue life has been found to be negligible in the range of lives 200 ⩽ N ⩽ 10,000 cycles when the mean strain does not exceed 1.5 times the total range. This effect, however, becomes important when the mean strain is several times the total strain range. In addition, for N < 200 cycles at failure, the effect of even a small value of the mean strain appears to be significant. The extension of a method previously developed is presented for establishing the high-temperature fatigue behavior under isothermal conditions with positive mean strain. On the basis of the results of a short-term tensile test, the technique gives predictions in good agreement with experimental data.

A Unified Viscoplastic Model for High Temperature Low Cycle Fatigue of Service-Aged P91 Steel

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
R. A. Barrett ◽  
T. P. Farragher ◽  
C. J. Hyde ◽  
N. P. O'Dowd ◽  
P. E. O'Donoghue ◽  
...  
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Material Model ◽  
Cyclic Softening ◽  
Flow Rule ◽  
Cycle Fatigue ◽  
Hyperbolic Sine

The finite element (FE) implementation of a hyperbolic sine unified cyclic viscoplasticity model is presented. The hyperbolic sine flow rule facilitates the identification of strain-rate independent material parameters for high temperature applications. This is important for the thermo-mechanical fatigue of power plants where a significant stress range is experienced during operational cycles and at stress concentration features, such as welds and branched connections. The material model is successfully applied to the characterisation of the high temperature low cycle fatigue behavior of a service-aged P91 material, including isotropic (cyclic) softening and nonlinear kinematic hardening effects, across a range of temperatures and strain-rates.

Low Cycle Fatigue Behavior of Q345b Steel under Uniaxial Cycle Loading

2014 ◽  
Vol 904 ◽  
pp. 95-98
Author(s):  
Xiang You ◽  
Rui Dong Wang ◽  
Shi Ming Cui ◽  
Yong Jie Liu ◽  
Qing Yuan Wang
Keyword(s):  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Constant Strain Rate ◽  
Strain Curve ◽  
Strain Range ◽  
Cyclic Stress ◽  
Cycle Fatigue ◽  
Cycle Loading ◽  
Reversed Cyclic ◽  
Q345b Steel

In this paper, the low cycle fatigue (LCF) behavior of Q345b steel was experimentally investigated in fully reversed cyclic axial configurations at room temperature. The strain range of 0.3%, 0.4%, 0.5%, 0.6% and 0.7% at constant strain rate of 0.005 s-1 was adopted. Cyclic stress-strain curve and strain life relationship were analyzed according to the Ramberg-Osgood relationship and Coffin-Manson relationship respectively. Suitable parameters were obtained showing good agreements with the experimental fatigue data.

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