scholarly journals High-cycle Fatigue Properties of Alloy718 Base Metal and Electron Beam Welded Joint

2015 ◽  
Vol 67 ◽  
pp. 1028-1035 ◽  
Author(s):  
Yoshinori Ono ◽  
Tetsumi Yuri ◽  
Nobuo Nagashima ◽  
Hideshi Sumiyoshi ◽  
Toshio Ogata ◽  
...  
Keyword(s):  
Electron Beam ◽  
Base Metal ◽  
High Cycle Fatigue ◽  
Welded Joint ◽  
Fatigue Properties ◽  
Cycle Fatigue

Fatigue Properties of AF1410 Steel Welded Joint by Electron Beam Welding

2011 ◽  
Vol 287-290 ◽  
pp. 2181-2184
Author(s):  
Bing Wu ◽  
Zhi Yong Mao ◽  
Jian Xun Zhang
Keyword(s):  
Electron Beam ◽  
Fatigue Limit ◽  
Fatigue Test ◽  
Base Metal ◽  
Welded Joints ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Fracture Morphology ◽  
Fatigue Properties ◽  
Test Conditions

Fatigue test of AF1410 steel and two thickness of electron beam have been done, and fatigue properties of the base metal and EB-welded joints have been studied. The results showed that fatigue limit of electron beam welded joints was close to that of base metal under this test conditions, and the welded thickness has little effect on S-N curves of electron beam welded samples under this test conditions. From SEM fracture morphology, it can be seen that fracture morphology of the welded samples was not obvious different form base metal. In the instant-off area of electron beam welded sample, there was dimple-like morphology showing good ductility.

Investigation on low cycle fatigue properties of CLAM steel electron beam welded joint at 550 °C

2021 ◽  
Vol 165 ◽  
pp. 112260
Author(s):  
Kaixuan Cui ◽  
Yanyun Zhao ◽  
Mengtian Liang ◽  
Bo Huang ◽  
Qunying Huang
Keyword(s):  
Electron Beam ◽  
Welded Joint ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Clam Steel

scholarly journals Failure mechanisms and fatigue strength reduction factor of a Cr-Ni-Mo-V steel welded joint up to ultra-long life regime

2018 ◽  
Vol 165 ◽  
pp. 21012 ◽  
Author(s):  
Ming-Liang Zhu ◽  
Fu-Zhen Xuan
Keyword(s):  
Fatigue Strength ◽  
Base Metal ◽  
High Cycle Fatigue ◽  
Welded Joint ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Cycle Fatigue ◽  
Strength Reduction Factor ◽  
Fatigue Design ◽  
Very High

It is known that welded joint is much “weaker” than base metal due to discontinuities of geometry, materials and residual stresses. It seems current international design rules do not adopt a uniform approach to weld efficiency, which is often defined as the ratio of the strength of a welded joint to the strength of base metal, in their guidance for creep and fatigue design of welds. This appears to be a great barrier for the application of nuclear welded structures which has a prolonged design lifetime of 60 years. In this work, fatigue strength reduction factor of a Cr-Ni-Mo-V steel welded joint, machined from welded steam turbine rotors for nuclear power plant, was investigated by performing axially push-pull cyclic loads tests with both cross-weld and pure base metal specimens up to very high cycle fatigue regime under ultrasonic frequency at ambient temperature. The effects of residual stress, strain localization, and microdefects in mismatched steels on failure mechanisms of welds were discussed thoroughly. Results show that fatigue strength reduction factor is varied in the range of 0.95-0.975, and is found to be dependent on fatigue lifetime for the first time. It is indicated that variation of fatigue strength reduction factor are associated with transition of crack initiation from specimen surface in high cycle fatigue regime to interior micro-defects in very high cycle fatigue regime. Comparing existing codes and standards for fatigue design of welds with experimental data indicates the over-conservativeness of present code-based design method. This implies a micro-defect based fatigue design approach is required for long life safe and reliability of weldments.

scholarly journals Usability of Ultrasonic Frequency Testing for Rapid Generation of High and Very High Cycle Fatigue Data

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2245
Author(s):  
Michael Fitzka ◽  
Bernd M. Schönbauer ◽  
Robert K. Rhein ◽  
Niloofar Sanaei ◽  
Shahab Zekriardehani ◽  
...  
Keyword(s):  
Strain Rate ◽  
High Cycle Fatigue ◽  
Fatigue Properties ◽  
Ultrasonic Frequency ◽  
Cycle Fatigue ◽  
Reinforced Polymer ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Fibre Reinforced Polymer ◽  
Very High

Ultrasonic fatigue testing is an increasingly used method to study the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) properties of materials. Specimens are cycled at an ultrasonic frequency, which leads to a drastic reduction of testing times. This work focused on summarising the current understanding, based on literature data and original work, whether and how fatigue properties measured with ultrasonic and conventional equipment are comparable. Aluminium alloys are not strain-rate sensitive. A weaker influence of air humidity at ultrasonic frequencies may lead to prolonged lifetimes in some alloys, and tests in high humidity or distilled water can better approximate environmental conditions at low frequencies. High-strength steels are insensitive to the cycling frequency. Strain rate sensitivity of ferrite causes prolonged lifetimes in those steels that show crack initiation in the ferritic phase. Austenitic stainless steels are less prone to frequency effects. Fatigue properties of titanium alloys and nickel alloys are insensitive to testing frequency. Limited data for magnesium alloys and graphite suggest no frequency influence. Ultrasonic fatigue tests of a glass fibre-reinforced polymer delivered comparable lifetimes to servo-hydraulic tests, suggesting that high-frequency testing is, in principle, applicable to fibre-reinforced polymer composites. The use of equipment with closed-loop control of vibration amplitude and resonance frequency is strongly advised since this guarantees high accuracy and reproducibility of ultrasonic tests. Pulsed loading and appropriate cooling serve to avoid specimen heating.

Laser Shock Processing of Ni-Base Superalloy and High Cycle Fatigue Properties

2011 ◽  
Vol 697-698 ◽  
pp. 235-238 ◽  
Author(s):  
L. Zhou ◽  
Y.H. Li ◽  
W.F. He ◽  
X.D. Wang ◽  
Q.P. Li
Keyword(s):  
High Cycle Fatigue ◽  
Laser Pulses ◽  
Fatigue Properties ◽  
Treatment Technique ◽  
Cycle Fatigue ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
First Order ◽  
Shock Processing ◽  
Base Superalloy

A plasma sound wave detection method of laser shock processing (LSP) technology is proposed. Speciments of Ni-base superalloy are used in this paper. A convergent lens is used to deliver 1.2 J, 10 ns laser pulses by a Q-switch Nd:YAG laser, operating at 1 Hz. The influence of the laser density to the shock wave is investigated in detail for two different wavelength lasers. Constant amplitude fatigue data are generated in room environment using notch specimens tested at an amplitude of vibration 2.8 mm and first-order flextensional mode. The results show that LSP is an effective surface treatment technique for improving the high cycle fatigue performance of Ni-base superalloys having a factor of 1.62 improvement in fatigue life.

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