Bending Fatigue Performance of Carburized Gear Steels

1992 ◽  
Author(s):  
Ray Sieber
Keyword(s):  
Fatigue Performance ◽  
Bending Fatigue ◽  
Carburized Gear ◽  
Gear Steels

scholarly journals Pitting and Bending Fatigue Evaluations of a New Case-Carburized Gear Steel

2007 ◽  
Author(s):  
Timothy Krantz ◽  
Brian Tufts
Keyword(s):  
Power Density ◽  
Fatigue Testing ◽  
Surface Hardness ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Surface Fatigue ◽  
Gear Steel ◽  
Single Tooth ◽  
Carburized Gear ◽  
Gear Steels

The power density of a gearbox is an important consideration for many applications and is especially important for gearboxes used on aircraft. One approach to improving power density of gearing is to improve the steel properties by design of the alloy. The alloy tested in this work was designed to be case-carburized with surface hardness of Rockwell C66 after hardening. Test gear performance was evaluated using surface fatigue tests and single-tooth bending fatigue tests. The performance of gears made from the new alloy was compared to the performance of gears made from two alloys currently used for aviation gearing. The new alloy exhibited significantly better performance in surface fatigue testing, demonstrating the value of the improved properties in the case layer. However, the alloy exhibited lesser performance in single-tooth bending fatigue testing. The fracture toughness of the tested gears was insufficient for use in aircraft applications as judged by the behavior exhibited during the single tooth bending tests. This study quantified the performance of the new alloy and has provided guidance for the design and development of next generation gear steels.

Bending Fatigue Behavior of Carburized Gear Steels: Four-Point Bend Test Development and Evaluation

1996 ◽  
Author(s):  
William E. Dowling ◽  
William T. Donlon ◽  
Warren B. Copple ◽  
Russell A. Chernenkoff ◽  
Craig V. Darragh
Keyword(s):  
Fatigue Behavior ◽  
Test Development ◽  
Bend Test ◽  
Bending Fatigue ◽  
Point Bend Test ◽  
Point Bend ◽  
Carburized Gear ◽  
Gear Steels ◽  
Four Point Bend Test

scholarly journals Bending Fatigue Behaviour and Fatigue Endurance Limit Prediction of 20Cr2Ni4A Gear Steel after the Ultrasonic Surface Rolling Process

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2516
Author(s):  
Zhiyuan Wang ◽  
Yangfei Huang ◽  
Zhiguo Xing ◽  
Haidou Wang ◽  
Debin Shan ◽  
...  
Keyword(s):  
Residual Stress ◽  
Surface Properties ◽  
Cross Section ◽  
Rolling Process ◽  
Fatigue Performance ◽  
Material Surface ◽  
Bending Fatigue ◽  
Surface Strengthening ◽  
Gear Steel ◽  
Carburized Gear

To study the effect of the surface properties on the bending fatigue performance of heavy-duty gear steel, the authors of this paper used the ultrasonic surface rolling process (USRP) to strengthen 20Cr2Ni4A carburized gear steel. USRP is a novel technique in which the ultrasonic technology is incorporated into the concept of conventional deep rolling. In this study, we illustrated how the surface properties and cross-section mechanical property influence the three-point bending fatigue life of the samples before and after USRP treatment. At the same time, the predicted failure probability-stress-number of cycles (P-S-N) curve was drawn, and the fatigue fracture was analysed. The results show that the fatigue limit increased from 651.36 MPa to 918.88 MPa after USRP treatment. The fatigue source is mainly from the sample interior or surface scratches, and the fatigue performance is positively correlated with the results of the material surface roughness, surface residual stress and surface hardness. At the same time, combined with the change in the phase structure, dislocation structure, residual stress and hardness of the cross section of the material, it is found that the USRP process turns the steel into a gradient material with five layers. Finally, the coupling mechanism between the ultrasonic surface strengthening deformation layer and the carburized layer of 20Cr2Ni4A carburized gear steel is presented, and the grain structure distribution diagram of the section of the 20Cr2Ni4A model after surface strengthening treatment was simulated. The mechanism that influenced the fatigue performance after USRP treatment is explained from the perspectives of the surface and cross section of the samples.

scholarly journals Fatigue Performance and Multiscale Mechanisms of Concrete Toughened by Polymers and Waste Rubber

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Bo Chen ◽  
Liping Guo ◽  
Wei Sun
Keyword(s):  
Fatigue Life ◽  
Polyvinyl Alcohol ◽  
Water Soluble ◽  
Fatigue Performance ◽  
Tire Rubber ◽  
Bending Fatigue ◽  
Waste Tire ◽  
Waste Rubber ◽  
Bonding Effect ◽  
Waste Tire Rubber

For improving bending toughness and fatigue performance of brittle cement-based composites, two types of water-soluble polymers (such as dispersible latex powder and polyvinyl alcohol powder) and waste tire-rubber powders are added to concrete as admixtures. Multiscale toughening mechanisms of these additions in concretes were comprehensively investigated. Four-point bending fatigue performance of four series concretes is conducted under a stress level of 0.70. The results show that the effects of dispersible latex powder on bending toughness and fatigue life of concrete are better than those of polyvinyl alcohol powder. Furthermore, the bending fatigue lives of concrete simultaneously containing polymers and waste rubber powders are larger than those of concrete with only one type of admixtures. The multiscale physics-chemical mechanisms show that high bonding effect and high elastic modulus of polymer films as well as good elastic property and crack-resistance of waste tire-rubber powders are beneficial for improving bending toughness and fatigue life of cementitious composites.

Cannulated Hip Screws: A Study of Fixation Integrity, Cut-out Resistance, and High-Cycle Bending Fatigue Performance

1994 ◽  
Vol 8 (4) ◽  
pp. 293-299 ◽  
Author(s):  
Jeffrey P. Rouleau ◽  
Ralph B. Blasier ◽  
Eugene Tsai ◽  
Steven A. Goldstein
Keyword(s):  
Fatigue Performance ◽  
Bending Fatigue

scholarly journals Bending Fatigue Behaviors Analysis and Fatigue Life Prediction of 20Cr2Ni4 Gear Steel with Different Stress Concentrations near Non-metallic Inclusions

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3443 ◽  
Author(s):  
Zhiguo Xing ◽  
Zhiyuan Wang ◽  
Haidou Wang ◽  
Debin Shan
Keyword(s):  
Fatigue Life ◽  
Quantitative Analysis ◽  
Steel Production ◽  
The State ◽  
Heavy Duty ◽  
Stress Concentrations ◽  
Bending Fatigue ◽  
Gear Steel ◽  
Gear Steels ◽  
The Relationship

To investigate the relationship between inclusions and bending fatigue behaviors in 20Cr2Ni4 steel under different stress concentrations. This paper designs a new experimental method to prefabricate different size stress concentrations near the inclusions, and then conducts a new type of bending fatigue test to study the inclusions and their surrounding stress distributions in 20Cr2Ni4 steel. A microhardness tester was combined with laser etching equipment to realize the prefabrication of different stress concentrations at arbitrary positions around any inclusion on the gear steel surface. This method provides an experimental basis for the quantitative analysis of the relationship between stress distribution and fatigue life around the inclusions of heavy-duty gear steels. We also predict the bending fatigue lives of heavy-duty gear steels with different types of inclusions, stress states, and spatial distributions. Then, based on the prefabricated notch parameters and the state of inclusions in the steel, a mathematical model of quantitative analysis is proposed, which can accurately predict the fatigue limit of heavy-duty gear steel. The research results can be applied to the actual use of heavy-duty gears and to the accurate life estimation based on the state of gear stress, thereby providing a quantitative reference model for subsequent gear steel production and gear part processing.

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