scholarly journals Effect of Severe Shot Peening on the Very-High Cycle Notch Fatigue of an AW 7075 Alloy

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1262 ◽  
Author(s):  
Michal Jambor ◽  
Libor Trško ◽  
Jan Klusák ◽  
Stanislava Fintová ◽  
Daniel Kajánek ◽  
...  
Keyword(s):  
Residual Stress ◽  
Shot Peening ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Fatigue Properties ◽  
Element Analysis ◽  
Near Surface ◽  
7075 Alloy ◽  
Severe Shot Peening ◽  
Very High

The severe shot peening process was applied to the notched specimens from an AW 7075 alloy with the aim to improve fatigue endurance in the very-high cycle fatigue region. To reveal the stress state in the notch vicinity, finite element analysis was performed, simulating the conditions of the used 20 kHz ultrasonic fatigue loading. Modified surface characteristics by the severe shot peening process were analyzed in terms of residual stress distribution measured by X-ray diffraction methods and near-surface microstructural observations by scanning electron microscopy. The applied severe shot peening increased the fatigue limit by 11%; however, the positive effect was recorded only for the loading amplitudes corresponding to the fatigue lifetimes in the range 107–109 cycles. At higher loading amplitudes, the fatigue properties tended to decrease, most likely due to accelerated fatigue crack initiation on the surface damage features created by the peening process and also by rapid residual stress relaxation.

scholarly journals Effects of Conventional and Severe Shot Peening on Residual Stress and Fatigue Strength of Steel AISI 1060 and Residual Stress Relaxation Due to Fatigue Loading: Experimental and Numerical Simulation

2020 ◽  
Author(s):  
Erfan Maleki ◽  
Gholam Hossein Farrahi ◽  
Kazem Reza Kashyzadeh ◽  
Okan Unal ◽  
Mario Gugaliano ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Residual Stress ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Experimental Investigations ◽  
Residual Stress Relaxation ◽  
Severe Shot Peening

Abstract This study investigates and compares the effects of different shot peening treatments including conventional and severe shot peening on microstructure, mechanical properties, fatigue behavior, and residual stress relaxation of AISI 1060 steel. Shot peening treatments were applied with two Almen intensities of 17 and 21 A and a wide ranges of coverage (100%–1500%). Various microstructural observations were carried out to analyze the evolution of microstructure. Microhardness, residual stress and surface roughness measurements and also axial fatigue test were performed. Moreover, the extent of the residual stress relaxation during cyclic loading was investigated by means of XRD measurements. Furthermore, numerical simulation of residual stress relaxation due to fatigue loading was carried out and validated against experimental investigations. The comparison indicated a good agreement for the surface residual stress relaxation up to 100 cycles. The experimental results indicated the efficiency of severe shot peening processes in obtaining nanostructured surface layer and achieving superior mechanical properties and fatigue behavior. Also, residual stress measurements revealed that stress relaxation started with a high rate at the initial stages of loading and gradually increased at higher number of cycles which was lower in the case of severely shot peened samples compared to the conventionally treated ones. Graphic Abstract

scholarly journals Effects of Shot Peening on Fretting Fatigue Crack Initiation Behavior

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 743 ◽  
Author(s):  
Xin Liu ◽  
Jinxiang Liu ◽  
Zhengxing Zuo ◽  
Huayang Zhang
Keyword(s):  
Residual Stress ◽  
Crack Initiation ◽  
Shot Peening ◽  
Contact Region ◽  
Stress Gradient ◽  
Fatigue Crack Initiation ◽  
High Stress ◽  
Fatigue Loading ◽  
Depth Direction ◽  
Crack Initiation Life

This study analyzes the effects of shot peening on the crack initiation behavior under fretting loading by using a numerical method. The residual stress relaxation and the contact stress evolution are both considered. The crack initiation life is predicted by the critical plane Smith–Watson–Topper (SWT) model. Considering that the fretting contact region has a high stress gradient along the depth direction, the process volume approach is adopted to calculate the SWT parameters. The results show that the remaining residual stress after relaxation strongly affects crack initiation life. The remaining residual stress decreases with the increase of fatigue loading, and the effect of shot peening on the improvement of crack initiation life is more obvious under smaller fatigue loading. Furthermore, under smaller fatigue loading, the crack initiation life of specimens with high shot peening intensity is longer than that of specimens with low shot peening intensity. However, the opposite phenomenon appears when the fatigue loading is large enough.

scholarly journals Effects of shot peening and artificial surface defects on fatigue properties of 50CrV4 steel

2021 ◽  
Vol 112 (9-10) ◽  
pp. 2961-2970
Author(s):  
Nursen Saklakoglu ◽  
Amir Bolouri ◽  
Simge Gencalp Irizalp ◽  
Fatih Baris ◽  
Ali Elmas
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Surface Defects ◽  
Fatigue Properties ◽  
Root Radius ◽  
Defect Depth ◽  
Near Surface ◽  
Artificial Surface

AbstractShot peening processes are commonly used for improving the fatigue properties of steels. Shot peening introduces a compressive residual stress field in the near surface of steel, which can reduce or stop the growth of fatigue cracks and improve fatigue properties. This study experimentally investigated the effect of shot peening on the fatigue properties of 50CrV4 steel alloys with different artificial surface defects. Drilling tools were used to introduce different artificial defects with root radii of 0.585 mm and 0.895 mm on the surface of unpeened samples. The shot peening was applied to the drilled and undrilled samples. Scanning electron microscopy (SEM) observations, micro-hardness and X-ray diffraction residual stress measurements were conducted to analyse the characteristics of the shot-peened and unpeened samples. The results show that the shot peening leads to the transformation of the retained austenite to martensite in the near-surface microstructure. The hardness rates of the surface and near surface both increase by 8% after the shot peening. The peened samples exhibit compressive residual stresses with a high degree of isotropy in the near surface. The fatigue properties of samples were experimentally evaluated by conducting 3-point bending tests. The results indicate that the shot peening improves the fatigue life of drilled and undrilled samples. For the defects with the root radius of 0.895 mm, the shot peening leads to a 500% improvement in the fatigue life compared to unpeened samples regardless of defect depth. For the defects with the root radius of 0.585 mm, the improvement in fatigue life is 40% for the defect depth of 0.2 mm compared to unpeened samples. The improvement increases to 60% and 200% by increasing the defect depths to 0.4 mm and 0.6 mm. The fatigue properties are linked to the changes in the features of defects mainly caused by the deformation hardening and compressive residual stress after shot peening.

Ultrasonic Characterization of Residual Stress in Shot Peened AI 7075 Alloy Using Acoustic Signature

2006 ◽  
Vol 321-323 ◽  
pp. 1475-1478 ◽  
Author(s):  
C.S. Kim ◽  
Dong Su Cho ◽  
Ik Keun Park
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Shot Peening ◽  
Acoustic Microscopy ◽  
Hardness Profile ◽  
Near Surface ◽  
Ultrasonic Characterization ◽  
Acoustic Signature ◽  
Al 7075 ◽  
7075 Alloy

We attempted to estimate the residual stress which evolved during the shot peening of Al 7075 alloy using leaky surface acoustic wave (LSAW). Shot peening was conducted to produce a variation in the compressive residual stress with the depth from the surface at a shot velocity of 30m/s. The LSAW velocity was measured using a scanning acoustic microscopy (SAM). The Vickers hardness profile obtained inwards from the surface showed significant work hardening of the near surface layer with a thickness of about 0.3mm. The variation in the LSAW velocity through the shot peened surface layer was in good agreement with the distribution of the residual stress measured by X-ray diffraction.

Influence of Shot Peening on Fatigue Properties in Ultra-High Strength Steels

2005 ◽  
Vol 490-491 ◽  
pp. 448-453 ◽  
Author(s):  
Yu Kui Gao ◽  
Xue Ren Wu ◽  
Feng Lu ◽  
Mei Yao ◽  
Qingxian Yan
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Fatigue Limit ◽  
Surface Integrity ◽  
Shot Peening ◽  
Fatigue Crack Initiation ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Properties ◽  
Ultra High Strength Steels

The characteristics of compressive residual stress fields induced by shot peening in 40CrNi2Si2MoVA, 16Co14Ni10Cr2Mo, 30CrMnSiNi2A and 0Cr13Ni8Mo2Al ultra-high strength steels, which are used widely in aeronautical industry were investigated, and the change of surface integrity including surface residual stress, surface roughness as well as its effects on fatigue properties were investigated. The results show that the fatigue limits of ultra-high strength steels can be increased by shot peening because the surface integrity can be ameliorated by shot peening, and that for a given steel there is a appropriate peening intensity under which the fatigue property of this steel is optimum. Finally, a judgement for the optimization condition of shot peening process is proposed based on a theory of micro-meso processes of fatigue crack initiation and experimental results. The technique should be considered to be optimum, if the fatigue crack source of shot peened specimen has been moved to the internal matrix metal region beneath the hardened layer; and its apparent fatigue limit has been improved and got to a value, which is near to that predicted according to the concept of surface/internal fatigue limit.

scholarly journals Analysing the Fatigue Behaviour and Residual Stress Relaxation of Gradient Nano-Structured 316L Steel Subjected to the Shot Peening via Deep Learning Approach

2021 ◽  
Author(s):  
Erfan Maleki ◽  
Okan Unal ◽  
Mario Guagliano ◽  
Sara Bagherifard
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Deep Learning ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Learning Approach ◽  
Residual Stress Relaxation

AbstractIn this study, the effect of kinetic energy of the shot peening process on microstructure, mechanical properties, residual stress, fatigue behavior and residual stress relaxation under fatigue loading of AISI 316L stainless steel were investigated to figure out the mechanisms of fatigue crack initiation and failure. Varieties of experiments were applied to obtain the results including microstructural observations, measurements of hardness, roughness, induced residual stress and residual stress relaxation as well as axial fatigue test. Then deep learning approach through neural networks was used for modelling of mechanical properties and fatigue behavior of shot peened material. Comprehensive parametric analyses were performed to survey the effects of different key parameters. Afterward, according to the results of neural network analysis, further experiments were performed to optimize and experimentally validate the desirable parameters. Based on the obtained results the favorable range of shot peening coverage regarding improved mechanical properties and fatigue behavior was identified as no more than 1750% considering Almen intensity of 21 A (0.001 inch). Graphic abstract

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%.

scholarly journals Fatigue Life Improvement of the High Strength Steel Welded Joints by Ultrasonic Impact Peening

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 619 ◽  
Author(s):  
Ján Lago ◽  
Libor Trško ◽  
Michal Jambor ◽  
František Nový ◽  
Otakar Bokůvka ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Welded Joints ◽  
Compressive Residual Stress ◽  
High Strength ◽  
Fatigue Properties ◽  
Low Alloy Steel ◽  
Residual Stress Field ◽  
Near Surface ◽  
Life Improvement

Ultrasonic impact peening was applied on welded joints manufactured from Strenx 700 MC high strength low alloy steel with the aim to improve the fatigue properties. Three different surface treatment parameters were tested, which resulted in transformation of the near-surface tensile residual stresses in the weld metal and heat affected zone to compressive residual stress field, while maximal values from −400 MPa up to −800 MPa were reached. The highest fatigue life improvement was reached by the double peening with the 85 N contact force, where the fatigue limit for N = 108 cycles increased from 370 MPa to 410 MPa.

Sign in / Sign up

Export Citation Format

Share Document