scholarly journals Residual Stress and Microstructure Characterization of 34CrMo4 Steel Modified by Shot Peening

Scanning ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Kejian Li ◽  
Xu Wu ◽  
Liping Chen ◽  
Dengming Chen ◽  
Gungjun Zhu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Shot Peening ◽  
Stress Test ◽  
Microstructure Characterization ◽  
Temper Brittleness ◽  
Face To Face ◽  
Lath Structure ◽  
Deformation Layer ◽  
34Crmo4 Steel

34CrMo4 steel is widely used for drill stem in oil exploration, because of its excellent properties, such as favorable hardenability, shock absorption, less tendency of temper brittleness, and eminent wear resistance. In this study, the main works are residual stress test and microstructure characterization of 34CrMo4 steel upon various shot peening treatments. The residual stress distribution with effect depth was studied upon the shot peening. Face-to-face paste sample preparation method is required for continuous observation for microstructure evolution of shot-peened specimen from the treat surface to matrix. Grain refinement, lath structure, and precipitates are clearly observed in the gradient deformation layer.

Characterization of nanocrystalline surface layer induced by shot peening and effect on their fatigue strength.

2004 ◽  
Vol 843 ◽  
Author(s):  
Hideo Mano ◽  
Kondo Satoru ◽  
Akihito Matsumuro ◽  
Toru Imura
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Fatigue Strength ◽  
Vickers Hardness ◽  
Shot Peening ◽  
White Layer ◽  
The Other ◽  
Fatigue Properties ◽  
Nanocrystalline Layer

ABSTRACTThe shot peening process is known to produce a hard layer, known as the white layer” on the surface of coil springs. However, little is known about the fatigue properties of this white-layer.In this study, coil springs with a white-layer were manufactured. The surface of these springs was then examined using micro Vickers hardness, FE-SEM etc. to test fatigue strength of the springs.From the results obtained, a microstructure of the white-layer with grain size of 50–100 nm was observed, with a Vickers hardness rating of 8–10 GPa.Tow category springs were manufactured utilizing a double-peening process. These springs had the same residual stress destruction and surface roughness. Only one difference was observed: one spring had a nanocrystalline layer on the surface, while the other did not. The results of the fatigue test realized an increase in the fatigue life of the nanocrystalline surface layer by 9%.

Characterization of Shot-Peened Surfaces by a Noncontacting Thermoelectric Method

2000 ◽  
Author(s):  
Hector Carreon ◽  
Peter B. Nagy
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Surface Layer ◽  
Dislocation Density ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Cold Work ◽  
Subsurface Layer ◽  
Thermoelectric Method

Abstract Shot peening is widely used in the aerospace and other industries to increase the damage tolerance of metal parts via producing a thin surface layer of compressive residual stress that prevents crack initiation and retards crack growth during service. Nondestructive evaluation of the prevailing compressive residual stress in the shallow subsurface layer is complicated by the adverse effects of shot peening, such as surface roughness and cold work that manifests itself through increased dislocation density and localized texture. Recent research efforts have revealed that conventional ultrasonic and eddy current NDT methods are simply too sensitive to surface roughness to quantitatively assess the subtle variations in mechanical and electrical properties that are caused by shot peening. On the other hand, noncontacting thermoelectric techniques are very unique among all other methods used in nondestructive materials characterization in that they are solely sensitive to intrinsic material variations regardless of the size, shape, and surface quality of the specimen to be tested. Noncontacting thermoelectric methods, based on magnetic detection of local thermoelectric currents around inhomogeneities in metals when a temperature gradient is established throughout the specimen, are especially well suited for the characterization of shot peened surfaces. Experimental evidence suggests that this method can reliably detect and quantitatively assess otherwise hidden variations in material properties within the shallow surface layer of shot peened specimens. The thermoelectric method is sensitive to all three “material” effects of shot peening, namely residual stress, local texture, and increased dislocation density, but it is entirely insensitive to its “geometrical” by-product, i.e., the rough surface topography. Further development of the thermoelectric method is necessary to study the underlying physical phenomena before it can be successfully adapted to practical inspection problems, but the preliminary results presented in this paper are very promising.

Characterization of CMOS Structures (0.6 µm process) Submitted to HBM and COM ESD Stress Tests

1997 ◽  
Author(s):  
G. Meneghesso ◽  
E. Zanoni ◽  
P. Colombo ◽  
M. Brambilla ◽  
R. Annunziata ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrostatic Discharge ◽  
Stress Test ◽  
Complete Characterization ◽  
Stress Tests ◽  
Test Procedures ◽  
Emission Microscopy ◽  
Fast Rise ◽  
Scanning Electron

Abstract In this work, we present new results concerning electrostatic discharge (ESD) robustness of 0.6 μm CMOS structures. Devices have been tested according to both HBM and socketed CDM (sCDM) ESD test procedures. Test structures have been submitted to a complete characterization consisting in: 1) measurement of the tum-on time of the protection structures submitted to pulses with very fast rise times; 2) ESD stress test with the HBM and sCDM models; 3) failure analysis based on emission microscopy (EMMI) and Scanning Electron Microscopy (SEM).

An intervention study on the effectiveness of an anti-stress-app on psychophysiological acute and chronic stress (Preprint)

2018 ◽  
Author(s):  
Franziska Lautenbach
Keyword(s):  
Chronic Stress ◽  
Acute Stress ◽  
Physiological Stress ◽  
Stress Test ◽  
Experimental Studies ◽  
Trier Social Stress Test ◽  
Control Group ◽  
Subjective Perception ◽  
Face To Face ◽  
Acute And Chronic Stress

BACKGROUND Dealing with stress is of central importance. Lately, smartphone applications (apps) are deployed in stress interventions as they offer maximal flexibility for users. First results of experimental studies show that anti-stress apps effect subjective perception of stress positively (Ly et al., 2014). However, current literature lacks studies on physiological stress reactions (e.g., cortisol), although they are of special interest to health issues. OBJECTIVE Therefore, the aim of this study was to investigate the effectiveness of an anti-stress app in chronic and acute stress reduction on a physiological (cortisol) and psychological level (subjective perception of stress) in comparison to a face-to-face and a control group in a pre-post design, for the first time. METHODS Sixty-two participants took part in the pretesting procedure (drop-out of 53 %). Based on age, gender, physical activity and subjectively perceived acute stress due to the Trier Social Stress Test for groups (TSST-G; von Dawans et al., 2011) as well as based on subjectively chronic stress assessed during the pretest, participants were parallelized in three groups (anti-stress-app: n = 10, face-to-face: n = 11, control group: n = 9). RESULTS After six weeks of the cognitive-based resource-oriented intervention, participants were exposed to the TSST-G for post testing. Results did not show a change of cortisol secretion or cognitive appraisal of the acute stressor. Further, no changes were detected in the chronic physiological stress reaction. CONCLUSIONS Possible causes are discussed extensively. CLINICALTRIAL no

scholarly journals Exploring the Characteristics and Influencing Factors of Leisure Walking Based on the Demand of Behavior

2021 ◽  
Vol 13 (8) ◽  
pp. 4105
Author(s):  
Yupei Jiang ◽  
Honghu Sun
Keyword(s):  
Health Benefits ◽  
Health Benefit ◽  
Public Health Research ◽  
Space Time ◽  
Time Behavior ◽  
Walking Behavior ◽  
Face To Face ◽  
Residential Neighborhood ◽  
The Impact

Leisure walking has been an important topic in space-time behavior and public health research. However, prior studies pay little attention to the integration and the characterization of diverse and multilevel demands of leisure walking. This study constructs a theoretical framework of leisure walking behavior demands from three different dimensions and levels of activity participation, space-time opportunity, and health benefit. On this basis, through a face-to-face survey in Nanjing, China (N = 1168, 2017–2018 data), this study quantitatively analyzes the characteristics of leisure walking demands, as well as the impact of the built environment and individual factors on it. The results show that residents have a high demand for participation and health benefits of leisure walking. The residential neighborhood provides more space opportunities for leisure walking, but there is a certain constraint on the choice of walking time. Residential neighborhood with medium or large parks is more likely to satisfy residents’ demands for engaging in leisure walking and obtaining high health benefits, while neighborhood with a high density of walking paths tends to limit the satisfaction of demands for space opportunity and health benefit. For residents aged 36 and above, married, or retired, their diverse demands for leisure walking are more likely to be fulfilled, while those with high education, medium-high individual income, general and above health status, or children (<18 years) are less likely to be fulfilled. These finding that can have important implications for the healthy neighborhood by fully considering diverse and multilevel demands of leisure walking behavior.

Shot peening parameters optimization based on residual stress-induced deformation of large fan blades

2021 ◽  
Vol 161 ◽  
pp. 107467
Author(s):  
Jiyin Zhang ◽  
Changfeng Yao ◽  
Liang Tan ◽  
Minchao Cui ◽  
Zhiqiang Lin ◽  
...  
Keyword(s):  
Residual Stress ◽  
Shot Peening ◽  
Parameters Optimization

Microstructure characterization of phase transformations in a Zn–22 wt%Al–2 wt%Cu alloy by XRD, SEM, TEM and FIM

2000 ◽  
Vol 313 (1-2) ◽  
pp. 154-160 ◽  
Author(s):  
Héctor J. Dorantes-Rosales ◽  
Vı́ctor M. López-Hirata ◽  
José L. Méndez-Velázquez ◽  
Maribel L. Saucedo-Muñoz ◽  
David Hernández-Silva
Keyword(s):  
Phase Transformations ◽  
Microstructure Characterization ◽  
Cu Alloy

Mechanical properties and microstructure characterization of coated AM2 Al 6061-T6 mats exposed to simulated thermal blast

2009 ◽  
Vol 16 (1) ◽  
pp. 1-10 ◽  
Author(s):  
C. Wilhelm ◽  
G. LaCaille ◽  
N. Wright ◽  
N. Ward ◽  
C. Shu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructure Characterization ◽  
Al 6061
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