Some Factors Influencing the Pitting, Micro-Pitting (Frosted Areas) and Slow Speed Wear of Surface Hardened Gears

1981 ◽  
Vol 103 (2) ◽  
pp. 499-505 ◽  
Author(s):  
H. Winter ◽  
T. Weiss
Keyword(s):  
Residual Stress ◽  
Carbon Content ◽  
Retained Austenite ◽  
White Layer ◽  
Load Capacity ◽  
Influence Factors ◽  
Surface Hardness ◽  
Considerable Influence ◽  
Slow Speed ◽  
Factors Influencing

Surface hardness and hardening depth are the most important influence factors for the load capacity of surface hardened gears. Besides the structure of the hardening pattern, it’s carbon content, amount of retained austenite, residual stress and white layer (nitrided gears) have a considerable influence. Lubricant and material of the mating gear as well as roughness of the tooth flanks have a different influence on pitting, micro-pitting and wear.

The Influence of Residual Stress and Tip Geometry on the Measurement of Surface Property Using Nanoindentation: Experimental Study and Numerical Analysis

2008 ◽  
Author(s):  
A. W. Warren ◽  
Y. B. Guo
Keyword(s):  
Residual Stress ◽  
Cross Sections ◽  
White Layer ◽  
Surface Hardness ◽  
Carbon Steels ◽  
Displacement Curve ◽  
Ultrafine Grained ◽  
Significant Difference ◽  
Load Displacement ◽  
Machined Surfaces

This study focuses on the basic relationships between nanohardness, residual stress, and micro/nanostructure of precision machined surfaces of high carbon steels. A series of nanoindentation tests were conducted on the cross-sections of the precision machined surfaces with ultrafine-grains or nanostructures. It was found that the nanostructured white layer significantly increases nanohardness, while the ultrafine-grained layer only slightly increases surface hardness. Residual stress affects the load-displacement curve shape at the onset of material yielding. Nanostructure makes a significant difference on the characteristics of a load-displacement curve, while ultrafine-grained structure exerts a slight influence. The influence of residual stress on the load-displacement curve can be estimated by finite element simulation of a nanoindentation. The simulation sensitivity analysis shows that the load-displacement curves are significantly affected by residual stress.

Microstructural Changes of SKD11 Steel during Carbide Dispersion Carburizing and Subzero Treatment

2006 ◽  
Vol 118 ◽  
pp. 115-120
Author(s):  
Jung Hyun Kong ◽  
Jang Hyun Sung ◽  
Sang Gweon Kim ◽  
Sung Wan Kim
Keyword(s):  
Carbon Content ◽  
Retained Austenite ◽  
Surface Hardness ◽  
Surface Region ◽  
M7c3 Carbide ◽  
Interior Region ◽  
Microstructural Changes ◽  
Surface Phases ◽  
Nano Size ◽  
Large Primary

Microstructural changes and hardness variations in SKD11 steel have been investigated during the processes of carbide dispersion (CD) carburizing, austenitization, subzero treatment and tempering. The carbon content of the surface region increased up to 3.0% after CD carburizing, and the surface phases consisted of two predominant types of M7C3 carbides (large primary eutectic M7C3 carbide and secondary M7C3 carbide), retained austenite and martensite. After austenitization, the carbon content of the surface region decreased to 2.4%. At the same time, surface hardness was reduced from 900Hv for the CD carburizing condition to 830Hv after austenitization. On the other hand, the hardness at the interior region of the austenitized steel displayed a 100Hv higher value than that of the CD carburizing steel. In spite of removal of the retained austenite, subzero treatment (at -100) of the austenitized steel resulted in a decrease in hardness, probably due to the softening of the martensite matrix. However, tempering (at 200 for 4 hours) of the subzero treated steel raised its hardness up about 70Hv compared to steel tempered without the subzero condition, due to precipitation of fine nano size carbides below 50nm.

Study of the Surface Integrity of Powder-Metallurgy High-Speed Steel (S390) Multi-Cut by Wire Electrical Discharge Machining

2013 ◽  
Vol 395-396 ◽  
pp. 1020-1025
Author(s):  
Xiang Zha ◽  
Chuan Liang Cao ◽  
Xiang Lin Zhang ◽  
Ji Jun Feng
Keyword(s):  
Residual Stress ◽  
Surface Integrity ◽  
Electrical Discharge ◽  
Retained Austenite ◽  
High Speed ◽  
Electrical Discharge Machining ◽  
White Layer ◽  
Great Influence ◽  
High Speed Steel ◽  
Wire Electrical Discharge Machining

The surface integrity of powder metallurgical high speed steel (S390) cut by wire electrical discharge machining (WEDM) has a great influence on the its fatigue life. In this paper, a study focused on surface integrity including white layer, surface finish, retained austenite, carbide and residual stress changed with multi-cutting has been described. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrograph (EDS) analysis were performed in the examination of the evolution of surface integrity. The experimental results reveal that the surface roughness, micro-cracks, white layer thickness and surface residual stress decrease with the increase of cutting pass, but the amount of retained austenite in the resolidified layer of the surface after the second cutting pass is the highest, compared with the other cutting passes. The content of carbides increases with the cutting pass and few carbides appear in the top section of the white layer of the first two cutting passes.

scholarly journals Residual Stress and Microstructural Characterization Using Rietveld Refinement of a Carburized Layer in a 5120 Steel

1995 ◽  
Vol 39 ◽  
pp. 319-329
Author(s):  
P. Rangaswamy ◽  
M.A.M. Bourke ◽  
A. C. Lawson ◽  
J.O' Rourke ◽  
J. A. Goldstone
Keyword(s):  
Residual Stress ◽  
Carbon Content ◽  
Rietveld Refinement ◽  
Retained Austenite ◽  
Microstructural Characterization ◽  
X Ray ◽  
Stress Measurements ◽  
Independent Technique ◽  
Carburized Layer ◽  
Diffraction Patterns

Rietveld refinement of X-ray diffraction patterns has been used to provide microstructural information complementary to conventional X-ray residual stress measurements through a carburized layer containing a maximum vol. 25 % of retained austenite. Layers in a simple specimen were removed incrementally by electropolishing and, at each depth in addition to conventional residual stress measurements in both the martensite and retained austenite, data were collected at ѱ = 0 for Rietveld refinement. The refinements provide accurate values for the lattice parameters in the respective phases that can be related to carbon content and micro-structure. Besides to providing qualitative information concerning the microstructure and possible surface decarburization, the c/a ratio of the martensite potentially offers an independent technique for determining carbon content profiles

Effects of low-temperature treatments on surface hardness, retained austenite content, residual stress condition and the resulting tooth root bending strength of case-hardened 18CrNiMo7-6 gears

2019 ◽  
Vol 233 (21-22) ◽  
pp. 7350-7357
Author(s):  
D Kratzer ◽  
F Dobler ◽  
T Tobie ◽  
T Hoja ◽  
M Steinbacher ◽  
...  
Keyword(s):  
Residual Stress ◽  
Low Temperature ◽  
Retained Austenite ◽  
Stress Condition ◽  
Bending Strength ◽  
Surface Hardness ◽  
Tooth Root ◽  
Austenite Content ◽  
Temperature Levels ◽  
Low Temperature Treatments

This paper contains parts of the research project FVA 612 and investigates the correlation between low-temperature treatments of case-hardened gears made from the material 18CrNiMo7-6 and the resulting surface hardness, retained austenite content, and residual stress condition. These parameters were further investigated with regard to the tooth root bending strength obtained with pulsating test rigs. The tested gears were subjected to various low-temperature treatments including different temperature levels before or after tempering. Other investigated parameters were the application of a shot blasting treatment and the effect of low-temperature treatments on gears with increased retained austenite content after the carburizing process.

The Properties and the Influence Factors of the White Layer in the Surface Grinding

2008 ◽  
Vol 53-54 ◽  
pp. 285-292 ◽  
Author(s):  
Cong Mao ◽  
Zhi Xiong Zhou ◽  
De Wang Zhou ◽  
Du Yi Gu
Keyword(s):  
Carbon Content ◽  
Layer Thickness ◽  
White Layer ◽  
Influence Factors ◽  
Central Zone ◽  
Surface Grinding ◽  
Cutting Depth ◽  
White Layer Thickness ◽  
Annealed Steel ◽  
Table Speed

The properties of the white layer in the surface grinding are described. The influences of heat treatment, carbon content and grinding conditions on the white layer formation are discussed. It is found that the white layer in the hardened steel is thicker and harder than that in the annealed steel, and there is not a softer transition zone in the annealed steel. Higher carbon content tends to increase white layer thickness at the larger cutting depth, while no difference is observed at the smaller cutting depth. Increased carbon content tends to increase white layer hardness. The white layer thickness increases as the cutting depth increases. The white layer thickness increases with the rise of the table speed until a certain critical speed value is reached, beyond which the white layer thickness decreases with the increase of the table speed. The white layer in the central zone of the workpiece is thicker than that in the entrance zone, but it is thinner than that in the exit zone.

Heat Treatment Effects on Distortion, Residual Stress, and Retained Austenite in Carburized 4320 Steel

2014 ◽  
Vol 783-786 ◽  
pp. 692-697 ◽  
Author(s):  
Andrew Clark ◽  
Randy J. Bowers ◽  
Derek O. Northwood
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Retained Austenite ◽  
Compressive Residual Stress ◽  
Surface Residual Stress ◽  
Depth Profiles ◽  
Size And Shape ◽  
Austenite Content ◽  
Treatment Conditions ◽  
The Difference

The effects of heat treatment on distortion, residual stress, and retained austenite were compared for case-carburized 4320 steel, in both the austempered and quench-and-tempered condition. Navy C-ring samples were used to quantify both size and shape distortions, as well as residual stress. The austempering heat treatment produced less distortion and a higher surface residual stress. Both hoop and axial stresses were measured; the difference between them was less than seven percent in all cases. Depth profiles were obtained for residual stress and retained austenite from representative C-ring samples for the austempered and quench-and-tempered heat treatment conditions. Austempering maintained a compressive residual stress to greater depths than quench-and-tempering. Quench-and-tempering also resulted in lower retained austenite amounts immediately beneath the surface. However, for both heat treatments, the retained austenite content was approximately one percent at depths greater than 0.5 mm.

Effects of Sequential Cuts on White Layer Formation and Retained Austenite Content in Hard Turning of AISI52100 Steel

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Xiao-Ming Zhang ◽  
Xin-Da Huang ◽  
Li Chen ◽  
Jürgen Leopold ◽  
Han Ding
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Retained Austenite ◽  
Hard Turning ◽  
White Layer ◽  
Layer Formation ◽  
White Layer Thickness ◽  
Austenite Content ◽  
Sequential Cuts ◽  
White Layer Formation

This technical brief is the extension of our previous work developed by Zhang et al. (2016, “Effects of Process Parameters on White Layer Formation and Morphology in Hard Turning of AISI52100 Steel,” ASME J. Manuf. Sci. Eng., 138(7), p. 074502). We investigated the effects of sequential cuts on microstructure alteration in hard turning of AISI52100 steel. Samples undergone five sequential cuts are prepared with different radial feed rates and cutting speeds. Optical microscope and X-ray diffraction (XRD) are employed to analyze the microstructures of white layer and bulk materials after sequential cutting processes. Through the studies we first find out the increasing of white layer thickness in the sequential cuts. This trend in sequential cuts does work for different process parameters, belonging to the usually used ones in hard turning of AISI52100 steel. In addition, we find that the white layer thickness increases with the increasing of cutting speed, as recorded in the literature. To reveal the mechanism of white layer formation, XRD measurements of white layers generated in the sequential cuts are made. As a result retained austenite in white layers is identified, which states that the thermally driven phase transformations dominate the white layer formation, rather than the severe plastic deformation in cuts. Furthermore, retained austenite contents in sequential cuts with different process parameters are discussed. While using a smaller radial feed rate, the greater retained austenite content found in experiments is attributed to the generated compressive surface residual stresses, which possibly restricts the martensitic transformation.

Einflussfaktoren in Routenzugsystemen*/Factors influencing internal milkrun systems - A method for calculating the intensity of influence of dimensioning parameters

2015 ◽  
Vol 105 (01-02) ◽  
pp. 65-71
Author(s):  
A. Martini ◽  
A. Rohe ◽  
U. Stache ◽  
F. Trenker
Keyword(s):  
Calculation Method ◽  
Influence Factors ◽  
Factors Influencing ◽  
Rank System ◽  
Factors Of Influence ◽  
Design Options ◽  
Specific Influence

Die Komplexität bei der Planung und Optimierung von Routenzugsystemen ist auf die Vielzahl der unterschiedlichen Gestaltungsmöglichkeiten und auf Interdependenzen zwischen den Einflussfaktoren zurückzuführen. Die im Fachartikel vorgestellte Verfahrensweise zur Einflussstärkenberechnung verschiedener Dimensionierungsparameter dient der Rangfolgebildung systemspezifischer Einflussfaktoren. Durch quantitativ-explorative Untersuchungen werden zudem Hypothesen für weitere Arbeiten gewonnen.   The complexity of planning and optimizing internal milkrun systems is a consequence of the multitude of different design options and interdependencies between the factors of influence. The calculation method for measuring the influence of different dimensioning parameters presented in this article serves to rank system-specific influence factors. Hypotheses for further research are obtained via quantitative-exploratory studies.

Sign in / Sign up

Export Citation Format

Share Document