scholarly journals Crack Initiation and Propagation in Rotating Bending Fatigue of Ti-6Al-4V Alloy.

1992 ◽  
Vol 41 (469) ◽  
pp. 1485-1491 ◽  
Author(s):  
Satoshi TANAKA ◽  
Hironobu NISITANI ◽  
Wataru FUJISAKI ◽  
Takahiro TERANISHI ◽  
Masahiko HONDA
Keyword(s):  
Crack Initiation ◽  
Crack Initiation And Propagation ◽  
Bending Fatigue ◽  
Initiation And Propagation ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

scholarly journals Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears

2007 ◽  
Author(s):  
Robert F. Handschuh ◽  
Timothy L. Krantz ◽  
Bradley A. Lerch ◽  
Christopher S. Burke
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Test Machine ◽  
Spur Gears ◽  
Crack Initiation And Propagation ◽  
Bending Fatigue ◽  
Initiation And Propagation ◽  
Single Tooth ◽  
Relationship Of ◽  
The Relationship

An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semi-logarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

Effect of Radical Nitriding on Fatigue Strength of Ni-Base Superalloy

2009 ◽  
Vol 417-418 ◽  
pp. 205-208 ◽  
Author(s):  
Kazuhiro Morino ◽  
Norio Kawagoishi ◽  
K. Yamane ◽  
K. Fukada
Keyword(s):  
Fatigue Strength ◽  
Base Alloy ◽  
Compound Layer ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Propagation Behavior ◽  
Initiation And Propagation ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Base Superalloy

In order to investigate the effect of nitriding on the crack initiation and propagation behavior of Ni-base super alloy, Alloy 718, rotating bending fatigue tests were carried out until 108 cycles at room temperature. By nitriding at 500°C for 12h, compound layer of about 5μm in thickness was formed and the initiation of a fatigue crack was strongly suppressed causing the increase in fatigue strength. A crack initiated in brittle manner at the compound layer in all of fractures. However the crack propagated in ductile manner controlled by the property of the base alloy. That is, there is no or little influence of nitriding on the crack growth rate of the alloy.

Influence of Grain Size on Notch Sensitivities in Fatigue of Carbon Steel

2008 ◽  
Vol 385-387 ◽  
pp. 197-200 ◽  
Author(s):  
T. Kanemaru ◽  
Norio Kawagoishi ◽  
Eiji Kondo ◽  
Qing Yuan Wang ◽  
Y. Ohzono
Keyword(s):  
Grain Size ◽  
Carbon Steel ◽  
Crack Initiation ◽  
Fatigue Tests ◽  
Crack Growth Resistance ◽  
Bending Fatigue ◽  
Fine Grained ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Circumferential Notch

In order to investigate the influence of grain size on notch sensitivities in fatigue of a fine-grained carbon steel, rotating bending fatigue tests were carried out using specimens with a V-grooved circumferential notch of commercial fine-grained carbon steel with grain size of 6.5µm. The results were compared with those of a larger grain sized carbon steel (grain size: 20 µm) and the notch sensitivities were evaluated based on Linear notch mechanics proposed by Nisitani. Notch sensitivities for both of fatigue limits for a crack initiation and its propagation of the fine grained steel were high. The results were discussed from the view points of the size of area related to crack initiation and the crack growth resistance.

scholarly journals Initiation and Propagation of Cracks in Rotating Bending Fatigue of IP-sintered SMF3.

1992 ◽  
Vol 58 (553) ◽  
pp. 1594-1599 ◽  
Author(s):  
Satoshi TANAKA ◽  
Hironobu NISITANI ◽  
Wataru FUJISAKI ◽  
Hiroyuki TANAKA ◽  
Takahiro TERANISHI
Keyword(s):  
Bending Fatigue ◽  
Initiation And Propagation ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

Effects of Microstructure and Humidity on Fatigue Strength of Maraging Steel

2008 ◽  
Vol 385-387 ◽  
pp. 113-116
Author(s):  
M. Miyazono ◽  
Norio Kawagoishi ◽  
Qing Yuan Wang ◽  
Eiji Kondo ◽  
Takanori Nagano
Keyword(s):  
Grain Size ◽  
Fatigue Strength ◽  
Fatigue Tests ◽  
Specimen Surface ◽  
Bending Fatigue ◽  
Maraging Steels ◽  
Initiation And Propagation ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Different Grain Size

Rotating bending fatigue tests were carried out for maraging steels with different grain size in moist air in order to investigate the effects of humidity, grain size and reversion austenite on fatigue strength of the steel. Fatigue strength was decreased by humidity, and the decrease in fatigue strength was large in larger grain sized steel. Both of the initiation and propagation of a crack were promoted by humidity. Many cracks initiated at the specimen surface and intergranular cracks were observed at specimen surface and on fracture surface when humidity was high. The decrease in fatigue strength by humidity was suppressed by formation of reversion austenite.

scholarly journals AN INVESTIGATION OF FATIGUE PROPERTIES OF PRE-QUENCHED-TEMPERED S45C STEEL WITH PLASMA NITRIDING TREATMENT

2012 ◽  
Vol 06 ◽  
pp. 233-238
Author(s):  
Bo Wu ◽  
Jianxun Zhang ◽  
Ri-ichi Murakami
Keyword(s):  
Fatigue Strength ◽  
Crack Initiation ◽  
Plasma Nitriding ◽  
Fatigue Properties ◽  
Surface Residual Stress ◽  
Layer Compound ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Fish Eye

Quenched and tempered (QT) S45C steel was processed by plasma nitriding (a mixture of 40% N 2-60% H 2, 400 Pa , 773 K ) with two different durations: 8 h and 48 h. The microhardness, surface residual stress and nitriding layer compound were separately detected and the effect was discussed with the fatigue test result. The rotating bending fatigue properties was test with QT, QT nitiding 8 h, QT nitriding 48 h specimens. Fish-eye type crack formation occurred and the two crack initiation modes, fish-eye crack initiation and surface crack initiation, were observed by the scanning electron microscope and discussed. The result showed that the fatigue strength of QT specimens were improved by 54% at least compared with the untreated specimens. But the QT and un-QT have the mainly same fatigue strength in the same plasma nitriding condition, especially no-improvement with the 48 h plasma nitriding specimens.

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