Improvement on pitting wear resistance of gears by controlled forging and plasma nitriding

Dalcin, Rafael Luciano; Menezes, Valcir Marques de; Oliveira, Leonardo Fonseca; Silva, Carlos Henrique da; Neves, Julio Cesar Klein das; Diehl, Carla Adriana Theis Soares; Rocha, Alexandre da Silva

doi:10.1016/j.jmrt.2022.04.122

Cited by 13 publications

(7 citation statements)

References 53 publications

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“…By contrast, an excessive furnace temperature can lead to the phase transition of the sample. When strengthening iron-based materials, the prevalently used temperatures are between 400-600 °C [27][28][29][30]. In this temperature range, as shown in figure 4, the electron density at the sampling point decreased slightly with increasing temperature.…”

Section: Resultsmentioning

confidence: 98%

Simulation of hollow-cathode-nitriding plasma and design of diffusion equipment with DC and RF dual discharge

Zhang¹,

Wang²,

Shao³

et al. 2023

Phys. Scr.

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The formation and diffusion of plasma are complex and critical processes in plasma nitriding. A stable and high-concentration plasma atmosphere can effectively increase the diffusion rate and the thickness of the diffusion layer. In this study, a two-dimensional multi-physics model integrating physical kinetics, energy transfer, mass transfer, and electromagnetic induction was developed. The effect of a hollow-cathode structure on plasma distribution was investigated, and the edge effect observed on nitrided metals was eliminated. The impacts of the essential plasma diffusion parameters were simulated using the developed model. A simple but effective experiment was designed to validate the model. A diffusion furnace with DC and RF dual discharge was designed by adding a high-frequency coil to existing equipment. Subsequently, the effects of the two plasma excitation sources on the overall distribution of plasma were analyzed. Notably, the proposed model is a high-fidelity one based on actual device dimensions; therefore, it can be used to simulate, predict, and control the plasma formation process in the diffusion furnace. In addition, the model can provide reference data and guidance for optimizing the diffusion process and structural design of diffusion furnaces.

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Section: Resultsmentioning

confidence: 98%

Simulation of hollow-cathode-nitriding plasma and design of diffusion equipment with DC and RF dual discharge

Zhang¹,

Wang²,

Shao³

et al. 2023

Phys. Scr.

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“…On the other hand, flank Hertzian stresses can develop in excess of 2000 MPa during operation that results in the need for special powder metallurgy steels, heat-treated case hardened and surface-treated steels in order to improve their contact strength. 8,9 The present work attempts to introduce the concept of advanced ceramic materials as alternatives to their steel counterparts through the exploration of the basic geometrical and operational advantages and limitations that would characterise them. Full ceramic gears can been found in the literature as shown in the works of Kyung-Hun et al, 10 Liu et al, 11 Hassanin and Jiang 12 and Reiterer et al 13 however they all relate to the micro-scale and not in high power transmission applications.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fully ceramic versus steel gears: Potential, feasibility and challenges

Vasileiou,

Rogkas,

Markopoulos

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part C:

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The most common gear strength calculations performed in accordance with ISO/TC 60/SC 2 include surface durability and root bending strength. Typical geared power transmissions are characterized by high Hertzian contact stresses (surface durability) on the flanks – frequently in the order of 103 MPa – versus almost half an order magnitude lower first principal stresses on the tooth root (tooth bending strength). Therefore, the use of high strength special steel alloys is almost mandatory, especially in high-end applications, mainly to withstand the high contact stress values. Ceramic materials are typically characterized by high compressive strength versus very low flexural strength that at first glance makes them inefficient for gear transmissions since they are unlikely to withstand the tensile root stresses. Nevertheless, ceramic materials possess a number of advantages that makes them potential candidates for geared transmissions, such as their exceptional thermal properties, their low density (weight), their excellent wear characteristics and limited lubrication demands. The present work investigates the main challenges of using high-end ceramic gears and attempts to provide an insight on defining the design envelope of such gears to counter the main disadvantages. The increase of the normal pressure angle beyond the 25° limit set by ISO 6336 is primarily investigated, since in minimizes the tensile tooth root stresses, while also increasing the curvature of the contact surfaces without greatly increasing Hertzian stresses. Comparative assessment of the performance of fully ceramic gear designs versus their conventional steel counterparts is performed through quasi-static FEA simulations to set the basic design requirements for such gears and to promote further investigation of the feasibility of their usage in high power density applications.

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“…Care with the surface finish of gear affects the durability of this component and its efficiency [11]. Microscopically modeling the coefficient of friction and considering it in contact stress calculations assist the development of new materials [12], new coating types [13,14], and new manufacturing processes [2,[10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study of contact fatigue for 18CrNiMo7-6 and 20MnCr5 carburized gear tooth

Calabokis¹,

Rosa²,

Moraes³

et al. 2022

Surf. Topogr.: Metrol. Prop.

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Gear manufacturers must make decisions about the manufacturing materials and superficial treatments. The best performance as to a type of failure should be evaluated. However, it is a time-demanding and costly process. The present work proposes a methodology for a comprehensive assessment (experimental and computational) of contact fatigue of gears in FZG test rig. The materials investigated were 18CrNiMo7-6 and 20MnCr5 alloy steels, widely used in industrial and automotive transmission systems, but with very different raw material costs, which can exceed twice the first compared to the second. The study evaluated the contact analysis between gears from the macroscopic point of view and the microscopic (inclusion of roughness). At the same time, the evolution of roughness and pit-damaged area after each test stage was monitored. The approach determined the stress field after each loading cycle and thus correlating the regions of higher stresses with surface and subsurface fatigue (micropitting and pitting). In addition, Weibull's statistical analysis and SEM-EDS observations were executed. In many cases, the methodology correlated the increased roughness and pitting affected area with the regions submitted to the higher contact stress. Observations by SEM-EDS revealed that the occurrence of plastic deformation as a mechanism of wear should be considered in the equations of microscopic stress analysis. The similar fatigue life of such different materials may be correlated to the competitive mechanisms of higher mechanical strength of 18CrNiMo7-6 and better crack propagation characteristics of 20MnCr5. The methodology proved to be consistent for fatigue failure analysis of gears in FZG test rig.

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Improvement on pitting wear resistance of gears by controlled forging and plasma nitriding

Cited by 13 publications

References 53 publications

Simulation of hollow-cathode-nitriding plasma and design of diffusion equipment with DC and RF dual discharge

Simulation of hollow-cathode-nitriding plasma and design of diffusion equipment with DC and RF dual discharge

Fully ceramic versus steel gears: Potential, feasibility and challenges

Experimental and numerical study of contact fatigue for 18CrNiMo7-6 and 20MnCr5 carburized gear tooth

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