scholarly journals Completely Reversed Axial and Torsional Low-Cycle Fatigue Properties of Carbon Steel at Room Temperature and Elevated Temperatures

1974 ◽  
Vol 40 (332) ◽  
pp. 907-915
Author(s):  
Zenji ANDO ◽  
Norihiko NAKANO
2016 ◽  
Vol 25 (9) ◽  
pp. 3822-3829 ◽  
Author(s):  
X. H. Dong ◽  
Q. D. Cao ◽  
S. J. Ma ◽  
S. H. Han ◽  
W. Tang ◽  
...  

2014 ◽  
Vol 3 ◽  
pp. 2201-2206 ◽  
Author(s):  
Seon-Jin Kim ◽  
Pil-Ho Choi ◽  
Rando Tungga Dewa ◽  
Woo-Gon Kim ◽  
Min-Hwan Kim

2004 ◽  
Vol 126 (3) ◽  
pp. 590-603 ◽  
Author(s):  
N. K. Arakere

Hot section components in high-performance aircraft and rocket engines are increasingly being made of single crystal nickel superalloys such as PWA1480, PWA1484, CMSX-4, and Rene N-4 as these materials provide superior creep, stress rupture, melt resistance, and thermomechanical fatigue capabilities over their polycrystalline counterparts. Fatigue failures in PWA1480 single crystal nickel-base superalloy turbine blades used in the space shuttle main engine fuel turbopump are discussed. During testing many turbine blades experienced stage II noncrystallographic fatigue cracks with multiple origins at the core leading edge radius and extending down the airfoil span along the core surface. The longer cracks transitioned from stage II fatigue to crystallographic stage I fatigue propagation, on octahedral planes. An investigation of crack depths on the population of blades as a function of secondary crystallographic orientation (β) revealed that for β=45+/−15 deg tip cracks arrested after some growth or did not initiate at all. Finite element analysis of stress response at the blade tip, as a function of primary and secondary crystal orientation, revealed that there are preferential β orientations for which crack growth is minimized at the blade tip. To assess blade fatigue life and durability extensive testing of uniaxial single crystal specimens with different orientations has been tested over a wide temperature range in air and hydrogen. A detailed analysis of the experimentally determined low cycle fatigue properties for PWA1480 and SC 7-14-6 single crystal materials as a function of specimen crystallographic orientation is presented at high temperature (75°F–1800°F) in high-pressure hydrogen and air. Fatigue failure parameters are investigated for low cycle fatigue data of single crystal material based on the shear stress amplitudes on the 24 octahedral and 6 cube slip systems for FCC single crystals. The max shear stress amplitude [Δτmax] on the slip planes reduces the scatter in the low cycle fatigue data and is found to be a good fatigue damage parameter, especially at elevated temperatures. The parameter Δτmax did not characterize the room temperature low cycle fatigue data in high-pressure hydrogen well because of the noncrystallographic eutectic failure mechanism activated by hydrogen at room temperature. Fatigue life equations are developed for various temperature ranges and environmental conditions based on power-law curve fits of the failure parameter with low cycle fatigue test data. These curve fits can be used for assessing blade fatigue life.


1965 ◽  
Vol 87 (2) ◽  
pp. 275-289 ◽  
Author(s):  
JoDean Morrow ◽  
F. R. Tuler

Completely reversed axial fatigue results are reported for Waspaloy and Inconel 713C at room temperature. Fatigue strength and ductility are evaluated using power functions of the fatigue life. The exponents and coefficients of these two equations are looked upon as four fatigue properties of the material. They appear in the equations which are developed to relate cyclic stress, plastic strain, total strain, plastic strain energy per cycle, total plastic strain energy to fracture, and fatigue life. These equations and the four fatigue properties permit the evaluation of the relative fatigue resistance of various metals at different fatigue lives when subjected to strain, stress, or plastic strain energy cycling. The “best” selection of material to resist fatigue is found to depend on the type of cycling and the desired life. At room temperature, the wrought Waspaloy is found to be more fatigue resistant than the cast Inconel 713C, particularly in resisting strain or plastic strain energy cycling in the low cycle fatigue region. For longer lives the difference in fatigue resistance between the two diminishes, especially for stress cycling. It is believed that the method of fatigue evaluation used here is generally applicable to the engineering problem of material selection to resist fatigue, and should in some cases replace methods based on conventional rotating bending fatigue tests which only evaluate the fatigue strength at long lives.


2019 ◽  
Vol 157 ◽  
pp. 109923 ◽  
Author(s):  
Zhen Zhang ◽  
Zhengfei Hu ◽  
Siegfried Schmauder ◽  
Baosen Zhang ◽  
Zhangzhong Wang

Author(s):  
Yoshiaki Matsumori ◽  
Jumpei Nemoto ◽  
Yuji Ichikawa ◽  
Isamu Nonaka ◽  
Hideo Miura

Since high-cycle fatigue loads is applied to the pipes in various energy and chemical plants due to the vibration and frequent temperature change of fluid in the pipes, the high-cycle fatigue behavior of the alloys used for pipes should be understood quantitatively in the structural reliability design of the pipes. The purpose of this study, therefore, is to clarify the high-cycle fatigue strength and fracture mechanism of the modified 9Cr-1Mo steel at temperatures higher than 400°C. This material is one of the effective candidates for the pipes in fast breeder demonstration reactor systems. A rotating bending fatigue test was applied to samples at 50 Hz in air. The stress waveform was sinusoidal and the stress ratio was fixed at −1. The fatigue limit was observed at room temperature and it was about 420 MPa. This value was lower than the 0.2% proof stress of this alloy by about 60 MPa. This decrease can be attributed to the cyclic softening of this material. The limited cycles at knee point was about 8×105 cycles. All fracture was initiated from a single surface crack and no inclusion-induced fracture was observed in the fracture surface by SEM. Thus, the high-cycle fatigue design based on the fatigue limit may be applicable to the modified 9Cr-1Mo steel at room temperature. The fatigue limit of about 350 MPa was also observed at 400°C, and it appeared at about 107 cycles, while it appeared at around 106 cycles at room temperature. Thus, it was confirmed that the fatigue strength of this alloy decrease with temperature. However, the fatigue limit didn’t appear at 550°C up to 108 cycles. The fatigue limit may disappear in this alloy at 550°C. It is very important, therefore, to evaluate the ultra-high cycle fatigue strength of this alloy at temperatures higher than 400°C.


Author(s):  
Hiroshi Nakamura ◽  
Masahiro Takanashi ◽  
Yu Itabashi ◽  
Hiroshi Kuroki ◽  
Yusuke Ueda

This study investigates the shot peening effect on low cycle fatigue properties of two turbo engine materials, Ti-6Al-4V and Inconel 718, in view of the residual stress relaxation by the cyclic load and the thermal relaxation. Strain controlled fatigue tests for Ti-6Al-4V were carried out at room temperature. The fatigue tests for Inconel 718 were conducted at room temperature and 620C. An X-ray diffraction method was used to measure the residual stresses induced by shot peening. The compressive residual stress of Ti-6Al-4V specimen had retained about 60% after half the number of cycles to failure. It is confirmed that shot peening enhances strain range capability of Ti-6Al-4V at the life between 104 and 105 cycles region about 1.5 times higher than that of non-peened specimen. This result is attributed to the retained compressive layer even after applied cyclic loading. Shot peening enhanced the strain range capability of the Inconel 718 specimen at room temperature, by a factor of 1.3 compared to polished specimen at the life of 104 cycles region. The residual stress near the surface has been relaxed rapidly at turbine engine temperature, however, the residual stresses in the deep subsurface have been retained. The peened specimen tested at 620C tended to be slightly higher strain range than those of polished specimen at the life of 105 cycles.


2008 ◽  
Vol 59 (2) ◽  
pp. 215-218 ◽  
Author(s):  
Tsutomu Tanaka ◽  
Atsumichi Kushibe ◽  
Masahide Kohzu ◽  
Yorinobu Takigawa ◽  
Kenji Higashi

2006 ◽  
Vol 118 ◽  
pp. 71-76 ◽  
Author(s):  
Jae Keun Hong ◽  
Ji Hong Park ◽  
Nho Kwang Park ◽  
Seong Jun Kim ◽  
Chung Yun Kang

Effects of solution treatment on the microstructure and mechanical properties in wrought Alloy 718 were investigated. For the improvement of tensile and fatigue properties of wrought Alloy 718, a modified solution heat treatment(MSHT), heating at 1000 for 3 minutes followed by furnace cooling at the rate of 3/minute and holding at 985 for 8 minutes, was proposed. This treatment was performed repeatedly 3 times and the samples were subject to the standard aging treatment. For the purpose of comparison, a standard heat treatment(SHT) was also performed. The microstructures of modified solution heat treated specimens showed that small spherical shaped δ- phases were precipitated without grain growth, and the amount of δ-phases was smaller than that of standard heat treated specimens. However, the δ-phases of the standard heat-treated specimen showed needle-like morphologies. Tensile and low cycle fatigue tests were performed on both modified heat-treated and standard heat-treated specimens at room temperature, 350 and 650. Low cycle fatigue tests on the modified heat treated specimens showed promising results without reduction of strength. However, the tensile properties of modified solution treated specimens was almost the same as those of standard heat treated materials both at room temperature and 650.


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