A Study on the Fatigue Characteristics of Al6061-T651 by Shot Peening Velocity

2006 ◽  
Vol 326-328 ◽  
pp. 1093-1096 ◽  
Author(s):  
Won Jo Park ◽  
Sun Chul Huh ◽  
Sung Ho Park
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Fatigue Life ◽  
Shot Peening ◽  
High Speed ◽  
Compressive Residual Stress ◽  
Velocity Increase ◽  
Fatigue Characteristics ◽  
Height Increase ◽  
Small Steel

Small steel ball is utilized in Shot peening process. Called “shot ball” are shot in high speed on the surface of metal. When the shot ball hit the surface, it makes plastic deformation and bounce off, that increase the fatigue life by compressive residual stress on surface. In this study, the results of observation on the tensile strength, hardness, surface roughness, compressive residual stress and fatigue life of a shot peened Al6061-T651 were obtained. Experimental results show that arc height increase tremendously by shot velocity. Also, it shows that surface roughness, hardness, compressive residual stress and fatigue life increase as shot velocity increase.

A Study on the Improvement of Durability of Gear Steel by Shot Peening

2006 ◽  
Vol 321-323 ◽  
pp. 662-665 ◽  
Author(s):  
Dong Sun Lee ◽  
Tae Hyung Kim ◽  
Jae Heon Lee ◽  
Tae Kun Lee ◽  
Seong Kyun Cheong
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Spur Gear ◽  
Sem Image ◽  
Gear Steel ◽  
Ball Velocity ◽  
Bending Fatigue Test ◽  
Fatigue Characteristics

In this paper the fatigue life of spur gear was investigated by changing the shot peening condition. From bending fatigue test depending on various shot peening intensity, fatigue characteristics were investigated. The causes of reduction in fatigue life were analyzed by observing the surface of gear with Scanning Electron Microscope(SEM), and impact of residual stress to fatigue characteristics was identified by measuring compressive residual stress depending peening intensity by depth. The results show that the optimum shot ball velocity is 65 m/s and optimum peening time is 8 minutes. From SEM image, the micro-crack was observed at the surface in case of over peening. This seems to be the factor which reduces fatigue life by decreasing compressive residual stress of surface.

scholarly journals Small–Scale Experimental Investigation of Fatigue Performance Improvement of Ship Hatch Corner with Shot Peening Treatments by Considering Residual Stress Relaxation

2021 ◽  
Vol 9 (4) ◽  
pp. 419
Author(s):  
Jin Gan ◽  
Zi’ang Gao ◽  
Yiwen Wang ◽  
Zhou Wang ◽  
Weiguo Wu
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Fatigue Life ◽  
Stress Relaxation ◽  
Stress Field ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Fatigue Performance ◽  
Residual Stress Field ◽  
Residual Stress Relaxation

Ship hatch corner is a common structure in a ship and its fatigue problem has always been one of the focuses in ship engineering due to the long–term high–stress concentration state during the ship’s life. For investigating the fatigue life improvement of the ship hatch corner under different shot peening (SP) treatments, a series of fatigue tests, residual stress and surface topography measurements were conducted for SP specimens. Furthermore, the distributions of the surface residual stress are measured with varying numbers of cyclic loads, investigating the residual stress relaxation during cyclic loading. The results show that no matter which SP process parameters are used, the fatigue lives of the shot–peened ship hatch corner specimens are longer than those at unpeened specimens. The relaxation rate of the residual stress mainly depends on the maximum compressive residual stress (σRSmax) and the depth of the maximum compressive residual stress (δmax). The larger the values of σRSmax and δmax, the slower the relaxation rates of the residual stress field. The results imply that the effect of residual stress field and surface roughness should be considered comprehensively to improve the fatigue life of the ship hatch corner with SP treatment. The increase in peening intensity (PI) within a certain range can increase the depth of the compressive residual stress field (CRSF), so the fatigue performance of the ship hatch corner is improved. Once the PI exceeds a certain value, the surface damage caused by the increase in surface roughness will not be offset by the CRSF and the fatigue life cannot be improved optimally. This research provides an approach of fatigue performance enhancement for ship hatch corners in engineering application.

The Ability of Current Models for Fatigue Life Prediction of Shot Peened Components

2009 ◽  
Vol 417-418 ◽  
pp. 901-904 ◽  
Author(s):  
Ricardo A. Cláudio ◽  
José M. Silva ◽  
Carlos M. Branco ◽  
Jim Byrne
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Fracture Mechanics ◽  
Shot Peening ◽  
Life Prediction ◽  
Compressive Residual Stress ◽  
Prediction Models ◽  
Critical Distance ◽  
Fatigue Life Prediction ◽  
Distance Methods

It is well known that shot peening has a marked benefit on fatigue life for the majority of applications. This effect is attributed mainly due to the compressive residual stress state at the component’s surface due to shot peening. The present paper evaluates the ability of several fatigue life prediction models, commonly used for general analyses, to predict the behaviour of components with compressive residual stress due to shot peening. Advanced elastic-plastic finite element analyses were carried out in order to obtain stress, strain, strain energy and fracture mechanics parameters for cracks within a compressive residual stress field. With these results several total fatigue life prediction models (including critical distance methods) and fracture mechanics based models were applied in order to predict fatigue life. Fatigue life predictions were compared with several experimental fatigue tests carried out on specimens, representative of a critical region of a compressor disc in a gas turbine aero engine. The results obtained showed that total fatigue life methods, even if combined with critical distance methods, give conservative results when shot peening is considered. Fatigue life was successfully predicted using the method proposed by Cameron and Smith, by adding initiation life to crack propagation life. This last method was also successfully applied for the prediction of non-propagating cracks that were observed during the experimental tests.

scholarly journals Improvement of mechanical properties and fatigue life by shot peening process on ASTM A516 Grade 70 steel

2018 ◽  
Vol 14 (4) ◽  
pp. 440-442
Author(s):  
Mohd Rashdan Isa ◽  
Omar Suliman Zaroog ◽  
Kalaikathir Murugan ◽  
Sharif Osman Kabashi Guma ◽  
Fareg Saeid Ali
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Fatigue Test ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Industrial Sector ◽  
Low Intensity ◽  
Before And After

ASTM A516 Grade 70 is widely used in the industrial sector as it provides very good mechanical properties in tough conditions. The main usage of this material is in moderate and low operating services. This paper focuses on the effect of shot peening process on ASTM A516 Grade 70 on improving the mechanical properties and fatigue life of the material. Samples have been shot peened with steel shot to induce compressive residual stress. Hardness, tensile and fatigue test as well as microstructure were done on the samples before and after shot peening process to study the effects on mechanical properties. The result shows that there is an increment in every test after shot peening process. There is a slight increment of 0.47% in hardness value, 0.39% increment in tensile strength and 6.78% increment in fatigue life of the material after shot peening process applied. The slight increment in every result was due to the low intensity of the shot peening process. Result also shows that the shot peening process compressed the molecules closer to each other as can be seen under SEM. Therefore it was proven that in this study, there is a very significant improvement in mechanical properties and fatigue life by shot peening process on ASTM A516 Grade 70 Steel.

Numerical Study on Strengthening Effect of Laser Shot Peening for Wrought Magnesium Alloy

2012 ◽  
Vol 217-219 ◽  
pp. 2234-2237 ◽  
Author(s):  
Su Qin Jiang ◽  
Hong Guang Xu
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Numerical Study ◽  
Back Analysis ◽  
Laser Shot ◽  
Fatigue Properties ◽  
Strengthening Effect ◽  
Fea Model

Based on finite element method, the FEA model used for analyzing fatigue properties of sample treated by laser shot peening (LSP) was established. In order to research the influence of material intensity on LSP effect, two kinds of wrought magnesium alloys AZ31B and ZK60 with different intensity were chosen as object, the compressive residual stress and fatigue life after LSP were analyzed. After spring back analysis the elastic strain is released in material inner, the value of compressive residual stress was reduced; after LSP with 3 times, the fatigue life gains of AZ31B and ZK60 were 105% and 163%, respectively. The results show that strengthening effect of high intensity material treated by LSP is better than that of low intensity material.

3D Computational Simulation of Multi-Impact Shot Peening

2012 ◽  
Vol 1485 ◽  
pp. 35-40
Author(s):  
Juan Solórzano-López ◽  
Francisco Alfredo García-Pastor
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Stress Field ◽  
Surface Treatment ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Fatigue Testing ◽  
Computational Simulation ◽  
Target Material ◽  
Residual Stress Field

ABSTRACTShot peening is a widely applied surface treatment in a number of manufacturing processes in several industries including automotive, mechanical and aeronautical. This surface treatment is used with the aim of increasing surface toughness and extending fatigue life. The increased performance during fatigue testing of the peened components is mainly the result of the sub-surface compressive residual stress field resulting from the plastic deformation of the surface layers of the target material, caused by the high-velocity impact of the shot. This compressive residual stress field hinders the propagation and coalescence of cracks during the second stage of fatigue testing, effectively increasing the fatigue life well beyond the expected life of a non-peened component.This paper describes a 3D computational model of spherical projectiles impacting simultaneously upon a flat surface. The multi-impact model was developed in ABAQUS/Explicit using finite element method (FEM) and taking into account controlling parameters such as the velocity of the projectiles, their incidence angle and different impact locations in the target surface. Additionally, a parametric study of the physical properties of the target material was carried out in order to assess the effect of temperature on the residual stress field.The simulation has been able to successfully represent a multi-impact processing scenario, showing the indentation caused by each individual shot, as well as the residual stress field for each impact and the interaction between each one of them. It has been found that there is a beneficial effect on the residual stress field magnitude when shot peening is carried out at a relatively high temperature. The results are discussed in terms of the current shot-peening practice in the local industry and the leading edge developments of new peening technologies. Finally, an improved and affordable processing route to increase the fatigue life of automotive components is suggested.

Experimental and Simulation Method of Introducing Compressive Residual Stress in ASTM A516 Grade 70 Steel

2019 ◽  
Vol 803 ◽  
pp. 27-31
Author(s):  
Mohd Rashdan Isa ◽  
Saiful Naim Sulaiman ◽  
Omar Suliman Zaroog
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Surface Treatment ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Tensile Loading ◽  
Simulation Method ◽  
Single Shot ◽  
Equivalent Amount ◽  
Simulation Procedure

Compressive residual stress below the surface of material could increase fatigue life as it encounters the tensile loading applied on the material during operation. Shot peening process is a common surface treatment to introduce this stress. This study will investigate on how to introduce the same amount of residual stress by simulation using FEM as introduced in experimental shot peening process. Actual shot peening process was done using a particular sets of parameters and FEM with single shot is used to simplify the simulation procedure. Result shows that using a single shot simulation could also introduce the equivalent amount of residual stress as in the experimental multi-shots shot peening process. This value could be used in further study to study the relaxation of the stress after load is being applied.

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.

scholarly journals Determination of the Optimal Coverage for Heavy-Duty-Axle Gears in Shot Peening

2021 ◽  
Author(s):  
Hongzhi Yan ◽  
Pengfei Zhu ◽  
Zhi Chen ◽  
Hui Zhang ◽  
Yin Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Dislocation Density ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Heavy Duty ◽  
High Coverage ◽  
Service Lifetime ◽  
Maximum Value

Abstract Pitting and wear often appear on heavy-duty-axle gears due to their harsh working conditions, such as high torques, high loads and poor lubrication. Shot peening is a popular surface strengthening method for gears. In order to ensure complete coverage during shot peening, 100%~200% coverage is usually prescribed for most gears. However, it is difficult to effectively improve the contact fatigue and wear resistance of heavy-duty-axle gears. Generally, increasing shot peening coverage can heighten the compressive residual stress for prolonging the service lifetime of gears. Whereas, high coverage levels may cause the deterioration of surface roughness, thus increase the noise and vibration of gears. To address this issue, this paper deals with the determination of optimal coverage for heavy-duty-axle gears by experimental tests. The influence of shot peening coverage on the surface integrity of gears is analyzed in terms of residual stress, microhardness, surface morphology and dislocation density. The results show that the maximum compressive residual stress increases first and then keeps stable with the increase of coverage, and the maximum value is −1172.10 MPa. The microhardness peak increases obviously in the beginning and then slowly rises with the increase of coverage, and the maximum value is 747.5 HV1.0. The surface roughness (Ra) decreases initially and then enhances with the increase of coverage, and the minimum value is 0.99 μm under the coverage of 1000%. The dislocation density increases with the increase of coverage, and the maximum value is 3.70×1016 m-2. Numerous damages (microscalings, spallings) occur on the treated gear tooth flank affecting the residual stress distribution and roughness under high coverage levels. Taking into consideration of service lifetime, working noise and economic efficiency, the coverage of 1000% is the optimal coverage for heavy-duty-axle gears in shot peening.

Sign in / Sign up

Export Citation Format

Share Document