Long Life Axial Fatigue Strength Models for Ferrous Powder Metals

2018 ◽  
Vol 11 (4) ◽  
pp. 467-479
Author(s):  
Virgiliu-Adrian Savu ◽  
Zissimos Mourelatos
Keyword(s):  
Fatigue Strength ◽  
Long Life ◽  
Powder Metals ◽  
Strength Models ◽  
Axial Fatigue

Fatigue Strength Assessment of a Structure Considering Corrosion Wastage and Corrosion Fatigue

2018 ◽  
Author(s):  
Norio Yamamoto ◽  
Tomohiro Sugimoto ◽  
Kinya Ishibashi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Strength ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Corrosion Fatigue ◽  
Life Assessment ◽  
Actual State ◽  
Corrosive Environment ◽  
Corrosion Fatigue Crack ◽  
Long Life

It is known that the fatigue strength decreases in corrosive environment and many experiments were carried out to comprehend the decrease in fatigue strength in corrosive environment. In order to comprehend the actual state, a cycle speed of fatigue test loads should correspond to a wave frequency. Therefore, an experiment in the long life region is practically difficult, then the corrosion fatigue data available for the life assessment of the structure is quite limited. In this study, the fatigue strength of the welded joints in long life service was evaluated according to the calculations of corrosion fatigue crack propagation subjected to the random loadings which followed an exponential distribution. In the crack propagation calculations, the progress of corrosion wastage from the plate surface and the resultant stress increase were considered simultaneously. In the high stress and the short life region, the decrease in fatigue strength due to the accelerated crack propagation in corrosive environment was dominant because the progress of corrosion wastage was little. On the other hand, in the low stress and the long life region, the decrease in fatigue strength became dull as longer the fatigue life because the corrosion fatigue crack propagation was suppressed by the corrosion wastage, but after that the fatigue strength showed the precipitous decrease due to the increase in stress resulted by the progress of corrosion wastage.

scholarly journals Long-Life Fatigue of Carburized 12Cr2Ni Alloy Steel: Evaluation of Failure Characteristic and Prediction of Fatigue Strength

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1006 ◽  
Author(s):  
Hailong Deng ◽  
Qichen Liu ◽  
Hang Liu ◽  
Huan Yu
Keyword(s):  
Fatigue Strength ◽  
Fatigue Limit ◽  
Alloy Steel ◽  
Extreme Values ◽  
Crack Size ◽  
Point Of View ◽  
Statistical Point ◽  
Surface Failure ◽  
Material Hardness ◽  
Long Life

In this study, the fatigue failure behaviors of carburized 12Cr2Ni alloy steel were examined in the long-life regime between 104 and 108 cycles with about 100 Hz under R = 0. Results showed that this alloy steel exhibited the double S-N characteristics with surface failure and interior failure. From a statistical point of view, the correlation coefficient further proved that the fine granular area (FGA) governed the fatigue performance of carburized 12Cr2Ni alloy steel. Based on the generalized extreme values (GEV) distribution and test data, the predicted maximum defect size was about 23.4 μm. Considering the effect of tensile limit, material hardness, and crack size characteristics, the fatigue strength prediction model under stress ratio of 0 could be established. The predicted fatigue limit for carburized 12Cr2Ni alloy steel at 108 cycles under R = 0 was 507.86 MPa, and the prediction error of fatigue limit was within 0.04. Therefore, the results were extremely accurate.

scholarly journals Influence of defects on axial fatigue strength of maraging steel specimens produced by additive manufacturing

2018 ◽  
Vol 165 ◽  
pp. 02005 ◽  
Author(s):  
Daniele Rigon ◽  
Giovanni Meneghetti ◽  
Michael Görtler ◽  
Daniele Cozzi ◽  
Wolfgang Waldhauser ◽  
...  
Keyword(s):  
Electron Beam ◽  
Fatigue Strength ◽  
Fatigue Test ◽  
Maraging Steel ◽  
Layer By Layer ◽  
Test Results ◽  
Powder Bed ◽  
Beam Laser ◽  
Laser Beam Melting ◽  
Axial Fatigue

Nowadays many materials such as steels, aluminium and titanium alloys can be realised by powder bed solutions melting subsequently powder layers by means of a laser or electron beam (Laser Beam Melting – LBM and Electron Beam Melting – EBM). The microstructure realised by layer-by-layer solidification having high cooling rate cannot be considered isotropic. Therefore, the mechanical properties could be influenced by the building direction. Regarding maraging steel, the study of the influence of the building direction and the heat treatment on the static and axial fatigue strength has been investigated in a previous contribution. A large scatter of the fatigue test results was found because of the presence of detrimental surface and subsurface defects. The aim of this contribution is to present additional axial fatigue test results of maraging steel characterized by different build orientation and providing an analysis of the defects observed at the crack initiation area of the fracture surface.

scholarly journals Mean Stress Effect on the Axial Fatigue Strength of DIN 34CrNiMo6 Quenched and Tempered Steel

Metals ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 213 ◽  
Author(s):  
Luis Pallarés-Santasmartas ◽  
Joseba Albizuri ◽  
Alexander Avilés ◽  
Rafael Avilés
Keyword(s):  
Fatigue Strength ◽  
Stress Effect ◽  
Mean Stress ◽  
Mean Stress Effect ◽  
Quenched And Tempered Steel ◽  
Tempered Steel ◽  
Axial Fatigue

2321 Effect of Hydrogen Gas Environment on Fretting Fatigue Strength in Long-Life Region

2007 ◽  
Vol 2007.6 (0) ◽  
pp. 183-184
Author(s):  
Kyohei KUWADA ◽  
Yasuhiro TANAKA ◽  
Masanobu KUBOTA ◽  
Yoshiyuki KONDO
Keyword(s):  
Fatigue Strength ◽  
Fretting Fatigue ◽  
Hydrogen Gas ◽  
Long Life ◽  
Gas Environment
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