Extraction and Testing of Miniature Compression Specimens From Bearing Balls Subjected to Rolling Contact Fatigue

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
B. D. Allison ◽  
G. Subhash ◽  
N. K. Arakere ◽  
H. Chin ◽  
D. Haluck ◽  
...  
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
High Strength ◽  
Fatigue Loading ◽  
Rolling Contact ◽  
Compression Tests ◽  
Material Degradation ◽  
Stress Strain ◽  
Surface Flatness ◽  
Miniature Specimens

Extraction and testing of miniature compression specimens from localized regions of components affected by rolling contact fatigue loading can provide significant insight into material degradation. Current ASTM standards for compression testing of cylindrical specimens become too stringent and difficult to achieve when specimen size is reduced to around 1 mm in diameter. The tolerances for surface flatness, parallelism of the loading surfaces, and the perpendicularity between the axis and the loading surfaces play crucial roles in the resulting stress-strain curves under uniaxial compression loading. In this manuscript, a systematic study is performed to quantify the influence of the above geometric parameters on the stress-strain response. Based on the analysis, the allowable geometric tolerances of miniature cylindrical specimens for a valid compression tests are recommended. The analysis results are validated and the usefulness of the method is demonstrated on miniature specimens extracted from the rolling contact fatigue affected regions of high strength M50 bearing balls. The yield stress within the rolling contact fatigue affected region is shown to increase by over 12%.

Effect of defect length on rolling contact fatigue crack propagation in high strength steel

2015 ◽  
Author(s):  
T. Makino ◽  
Y. Neishi ◽  
D. Shiozawa ◽  
Y. Neishi ◽  
D. Shiozawa ◽  
...  
Keyword(s):  
Crack Propagation ◽  
High Strength Steel ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
High Strength ◽  
Rolling Contact ◽  
Micro Ct ◽  
Middle Line ◽  
Micro Computed Tomography ◽  
Depth Direction

 The objective of the present paper is to clarify the effect of defect length in depth direction on rolling contact fatigue (RCF) crack propagation in high strength steel. RCF test and synchrotron radiation micro computed tomography (SR micro CT) imaging were conducted. In the case of the defect with the 15 ?m diameter, flaking life decreased with increasing defect length. In a comparison of the CT image and the SEM view, the shapes of defects and the locations of the horizontal cracks were almost the same respectively. The mechanism of RCF crack propagation was discussed by finite element (FE) analysis. Defects led to higher tensile residual stress than that without defects in the region where the defect exists. The shear stress range at 0.1 mm in depth on the middle line of the defect and the range of mode II stress intensity factor at the bottom of a vertical crack increased with increasing defect length.

Rolling Contact Fatigue of Titanium Alloys Coated by Gas Nitriding Using a Q-Sw Laser

2011 ◽  
Vol 83 ◽  
pp. 191-196
Author(s):  
Justyna Rozwadowska ◽  
Katsuyuki Kida ◽  
Edson Costa Santos ◽  
Takashi Honda ◽  
Hitonobu Koike ◽  
...  
Keyword(s):  
Titanium Alloys ◽  
Rolling Contact Fatigue ◽  
Pure Titanium ◽  
Contact Fatigue ◽  
Weight Ratio ◽  
High Strength ◽  
Rolling Contact ◽  
Wear Loss ◽  
Beam Diameter ◽  
Gas Nitriding

The influence of gas nitriding of commercial pure titanium and Ti-6Al-4V (Ti64) alloy by using a Q-sw laser on the wear loss during rolling contact fatigue is investigated. Despite very good biocompatibility, high strength to weight ratio and corrosion resistance, the tribological properties of titanium alloys are inferior to those of other metal alloys, such as steel. Fretting and wear related aspects become important issues when titanium alloys are used in rolling contact applications. Titanium bearings are employed in applications requiring high strength, light weight, and minimum maintenance (for example, aerospace and defense industries). In this work, a Q-sw laser was used to coat pure commercial titanium and Ti-6Al-4V bearings with TiN in a closed chamber in nitrogen atmosphere. The samples were tested under water by using a thrust-type rolling contact fatigue machine. The microstructure, morphology and crystallographic texture of the layers were observed by laser confocal microscope, scanning electron microscope and electron backscatter diffraction (EBSD). By optimizing the laser processing parameters, such as laser scanning speed, power and beam diameter, thin TiN coats of 1 to 3 mm were produced. The wear loss of the coated samples was at least ten times lower than that of the uncoated bearings.

Influence of Repeated Quenching on Bearing Steel Martensitic Structure Investigated by Homology

2013 ◽  
Vol 372 ◽  
pp. 270-272 ◽  
Author(s):  
Kazuaki Nakane ◽  
Katsuyuki Kida ◽  
Takashi Honda ◽  
Koshiro Mizobe ◽  
Edson Costa Santos
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
High Strength ◽  
Bearing Steel ◽  
Rolling Contact ◽  
High Carbon ◽  
Mathematical Methods ◽  
Heat Treated ◽  
Laser Confocal Microscope ◽  
Steel Heat

JIS SUJ2 (high carbon high strength bearing steel) heat treated by repeated quenching was investigated. The microstructure of the bearing traces was observed after heat treatment by laser confocal microscope. In this paper, by mathematical methods, we try to evaluate quantitatively this change of the structure. Homology is a branch of mathematics that allows quantitative describing characteristics of a figure by replacing the figure with algebra. Applying homology we can express the degree of the connection of the figure. Here we use homology to quantify the change of structures by repeated quenching. Keyword: Homology, Rolling contact fatigue, SUJ2, repeated quenching

18CrNiMo7-6 with TRIP-Effect for Increasing the Damage Tolerance of Gear Components — Part I: Alloy Design

2014 ◽  
Vol 783-786 ◽  
pp. 633-638
Author(s):  
Margarita D. Bambach ◽  
Andreas Stieben ◽  
Wolfgang Bleck
Keyword(s):  
High Performance ◽  
Damage Tolerance ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
High Strength ◽  
Residual Austenite ◽  
Rolling Contact ◽  
Optimum Process ◽  
Trip Effect ◽  
Stress Concentrations

High performance components such as gear wheels shall be resistant to rolling-contactfatigue. This type of failure is usually caused by effects occurring on a microscopic scale, such ascrack initiation at non-metallic inclusions. Much effort has been invested so far in improving thesteel cleanliness. However, these high performance components often do not reach the desiredservice life. Preliminary failure within the guarantee terms still occurs which leads to high warrantycosts. Alternative to improving steel cleanliness, the damage tolerance of high performancecomponents could be increased by inducing the TRIP-effect around the crack tip. Due to high localstrain hardening, martensite transformation occurs. The high compressive stresses related to it coulddelay or stop crack propagation by reducing stress concentrations via plastic deformation. As aresult, rolling-contact fatigue resistance of carburized steels may be increased and preliminaryfailure may be avoided. Part I of this study focuses on modifying the chemical composition ofconventional 18CrNiMo7-6 steel with Al to develop a high-strength, yet ductile matrix with a highwork hardening potential. Dilatometric tests on laboratory melts analyze the possibility of adjustinga microstructure able to produce a TRIP-effect. Both isothermal annealing and Quenching andPartitioning (Q&P) are used to stabilize residual austenite and optimum process routes areidentified.

scholarly journals Rolling Contact Fatigue Damage from Artificial Defects and Sulphide Inclusions in High Strength Steel

2017 ◽  
Vol 7 ◽  
pp. 468-475 ◽  
Author(s):  
Taizo Makino ◽  
Yutaka Neishi ◽  
Daiki Shiozawa ◽  
Shoichi Kikuchi ◽  
Hitoshi Saito ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
High Strength Steel ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
High Strength ◽  
Rolling Contact
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