The Overload Retardation Effect in Fatigue Crack Propagation of Worm-Like Graphite Cast Iron

1991 ◽  
Vol 113 (3) ◽  
pp. 307-313
Author(s):  
Ange Zhang ◽  
Thang Bui-Quoc ◽  
Xunfang Sun
Keyword(s):  
Cast Iron ◽  
Crack Size ◽  
Retardation Effect ◽  
Stress Intensity Range ◽  
Load Range ◽  
R Ratio ◽  
Graphite Cast Iron ◽  
Significant Difference ◽  
Effective Stress Intensity Range ◽  
Number Of Cycles

In this paper, single and multiple overloading tests under cyclic controlled stress were carried out on specimens of Worm-like Graphite Cast Iron (WGCI), a brittle material. The results showed that the overloading had a strong retardation effect on this material when the overload ratio r (ratio between the overload range and the baseline load range) is larger than 1.2. For example, the number of cycles of retardation due to overloading, N’, may be as high as ten times the cycles, N, required for the same crack length under baseline loading. In addition, for the testing conditions examined, there is no significant difference in the retardation effect under single or multiple overloading for this material. An analytical model based on the concept of crack closure and the effective stress intensity range was developed for evaluating the effect of the retardation. The development led to a correlation between the number of applied cycles and the crack size after overloading and permits to calculate the retardation cycles N’. Finally, the mechanisms attributed to the retardation effect for WGCI are discussed.

Color Etching for Characterization the Grain Orientation in Spheroidal Graphite Cast Iron

2007 ◽  
Vol 537-538 ◽  
pp. 389-396 ◽  
Author(s):  
Ibolya Kardos ◽  
Zoltán Gácsi ◽  
Péter János Szabó
Keyword(s):  
Cast Iron ◽  
Crystallographic Orientation ◽  
Grain Orientation ◽  
Test Material ◽  
Spheroidal Graphite ◽  
Metallic Materials ◽  
Additional Information ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
Back Scattering

Color etching is a widely used technique for visualizing different phases in metallic materials. Its advantage to the traditional etching techniques is that it gives additional information within one phase, namely, the color shade of a given phase can change in a certain range. This paper demonstrates that, due to the physics of the color etching, the shade of a phase also depends on the crystallographic orientation of the investigated grain. As a test material, spheroidal graphite cast iron was used, and individual grain orientation was identified by automated electron back scattering diffraction (EBSD). Results showed that there is a strong correlation between grain orientation and the shades obtained by color etching.

scholarly journals Quantitative models for microstructure and thermal conductivity of vermicular graphite cast iron cylinder block based on cooling rate

China Foundry ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 52-59
Author(s):  
Qing-yi Liu ◽  
Xiao-fu Zhang ◽  
Yu-cheng Sun ◽  
Ai-long Jiang ◽  
Ji-chao Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Cast Iron ◽  
Cooling Rate ◽  
Cylinder Block ◽  
Quantitative Models ◽  
Graphite Cast Iron ◽  
Block Based

scholarly journals Influences of Residual Stress, Surface Roughness and Peak-Load on Micro-Cracking: Sensitivity Analysis

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 320
Author(s):  
Jairan Nafar Dastgerdi ◽  
Fariborz Sheibanian ◽  
Heikki Remes ◽  
Hossein Hosseini Toudeshky
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Crack Formation ◽  
Peak Load ◽  
Crack Size ◽  
Effective Parameters ◽  
Load Range ◽  
Load Effect ◽  
Damage Initiation ◽  
Load Conditions

This paper provides further understanding of the peak load effect on micro-crack formation and residual stress relaxation. Comprehensive numerical simulations using the finite element method are applied to simultaneously take into account the effect of the surface roughness and residual stresses on the crack formation in sandblasted S690 high-strength steel surface under peak load conditions. A ductile fracture criterion is introduced for the prediction of damage initiation and evolution. This study specifically investigates the influences of compressive peak load, effective parameters on fracture locus, surface roughness, and residual stress on damage mechanism and formed crack size. The results indicate that under peak load conditions, surface roughness has a far more important influence on micro-crack formation than residual stress. Moreover, it is shown that the effect of peak load range on damage formation and crack size is significantly higher than the influence of residual stress. It is found that the crack size develops exponentially with increasing peak load magnitudes.

scholarly journals Cyclic fatigue resistance of 2Shape, Twisted File and EndoSequence Xpress nickel-titanium rotary files at intracanal temperature

2018 ◽  
Vol 12 (4) ◽  
pp. 283-287 ◽  
Author(s):  
Gülşah Uslu ◽  
Taha Özyürek ◽  
Mustafa Gündoğar ◽  
Koray Yılmaz
Keyword(s):  
Fatigue Resistance ◽  
Statistical Significance ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Bonferroni Correction ◽  
Significant Difference ◽  
Inner Diameter ◽  
The Difference ◽  
Number Of Cycles ◽  
Analyze Data

Background. The aim of this study was to compare the cyclic fatigue resistance of 2Shape, Twisted File (TF) and EndoSequence Xpress (ESX) nickel-titanium rotary files at intracanal temperature (35°C). Methods. Twenty 2Shape TS1 (25/.04), 20 TF (25/.04) and 20 ESX (25/.04) files were tested for cyclic fatigue at intracanal temperature (35°C). All the instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds using a digital chronometer and the number of cycles to fracture (NCF) for each file was calculated. Kruskal-Wallis test with Bonferroni correction was performed to statistically analyze data using SPSS 21.0. Statistical significance was set at P<0.05. Results. NCF values revealed that the 2Shape had significantly the highest cyclic fatigue resistance, followed by TF and ESX at intracanal temperature (P<0.05). The difference was significant between the TF and ESX groups (P<0.05). There was no significant difference among the 2Shape, TF and ESX files with respect to the lengths of the fractured file fragments (P>.05). Conclusion. Within the limitations of present study, it was concluded that the cyclic fatigue resistance of 2Shape files at the intracanal temperature is higher than that of TF and ESX files.

Progress of erosive wear in spheroidal graphite cast iron

Wear ◽  
1996 ◽  
Vol 198 (1-2) ◽  
pp. 150-155 ◽  
Author(s):  
K. Shimizu ◽  
T. Noguchi ◽  
T. Kamada ◽  
H. Takasaki
Keyword(s):  
Cast Iron ◽  
Erosive Wear ◽  
Spheroidal Graphite ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron

scholarly journals Copper Enrichment around Graphite in Cu-added High-Strength Spheroidal Graphite Cast Iron

Materia Japan ◽  
2009 ◽  
Vol 48 (12) ◽  
pp. 624-624 ◽  
Author(s):  
Yasuhide Ishiguro ◽  
Kenji Ichino ◽  
Hideto Takasugi
Keyword(s):  
Cast Iron ◽  
High Strength ◽  
Spheroidal Graphite ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron
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