scholarly journals Investigation of residual stress, stress relaxation and work hardening effects induced by shot peening on the fatigue life of AA 6005-T6 aluminum alloy

2020 ◽  
Vol 6 (12) ◽  
pp. 1265i2 ◽  
Author(s):  
Martin Ferreira Fernandes ◽  
Marcelo Augusto Santos Torres ◽  
Maria da Penha Cindra Fonseca ◽  
Carlos Antonio Reis Pereira Baptista
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Fatigue Life ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Work Hardening

scholarly journals Micro-Hardness and Residual Stress Relaxation of 2024 T351 Aluminum Alloy

2011 ◽  
Vol 462-463 ◽  
pp. 343-348 ◽  
Author(s):  
Omar Suliman Zaroog ◽  
Aidy Ali ◽  
Sahari B. Barkawi ◽  
Rizal Zahari
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Relaxation ◽  
Shot Peening ◽  
X Ray Diffraction ◽  
Initial State ◽  
Load Amplitude ◽  
Initial Residual Stress ◽  
Residual Stress Relaxation ◽  
Two Stages

The residual stress relaxation can be divided into two stages: The first cycle relaxation and the following cycles. In both stages, residual stress relaxed considerably from the initial state. The aim of this study is to investigate the residual stress relaxation and microhardness reduction after first and second cyclic load. A 2024 T351 aluminum alloy specimens were shot peened into three shot peening intensities. The fatigue test for first and second cyclic loads of two loads 15.5 kN and 30 kN was performed. The initial residual stress and residual stress after the first and second cycle stress was measured for the three shot peening intensities using X-ray diffraction. Microhardness test was performed for each specimen. The results showed that the residual stress relaxation for first cycle was reached more than 40% of the initial residual stress and it depends on the load amplitude, and microhardness decreased for the first cycle reached 22% and also it depended on load amplitude.

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.

Surface Yield Strength Gradient versus Residual Stress Relaxation of 7075 Aluminum Alloy

2010 ◽  
Vol 160-162 ◽  
pp. 241-246 ◽  
Author(s):  
Yong Hui Hu ◽  
Yun Xin Wu ◽  
Guang Yu Wang ◽  
Jun Kang Guo
Keyword(s):  
Residual Stress ◽  
Aluminum Alloy ◽  
Stress Relaxation ◽  
Yield Strength ◽  
Residual Stresses ◽  
Shot Peening ◽  
Fatigue Property ◽  
7075 Aluminum Alloy ◽  
Residual Stress Relaxation ◽  
Stress Coefficient

Different distributed residual stresses were introduced by quenching and two shot-peening treatments on 7075 aluminum alloy. The residual stress distributions and micro-hardness profiles in surface layers were measured. Pre-stress coefficient characterizing contribution of local residual stresses to local yield strength is introduced to analyze residual stress relaxation under cyclic loading. Load testing shows that re-distribution of residual stresses and proportional decrease of the pre-stress coefficient would occur in the non-uniform structural residual stresses introduced by quenching, while great stress relaxation and non-linear decrease of the pre-stress coefficient would occur in the uniform surface residual stresses introduced by shot-peening. Additionally, advantages of surface compressive residual stress and micro yield strength on anti-fatigue property and on restraining initiation and propagation of surface micro cracks should be considered in the usually conservative engineering design.

scholarly journals Prediction of Residual Stress Relaxation of Shot Peened 2024-T351 Aluminum Alloy: Part 1

2011 ◽  
Vol 462-463 ◽  
pp. 1355-1360
Author(s):  
Omar Suliman Zaroog ◽  
Aidy Ali ◽  
Sahari B. Barkawi
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Applied Load ◽  
Cold Work ◽  
Cyclic Tests ◽  
Initial State ◽  
Loading Cycle ◽  
Residual Stress Relaxation ◽  
Alloy Part

It is important to account for residual stress relaxation phenomenon in the design of the component. Specimens of 2024-T351 aluminium alloy were used in this study. The specimens were shot peened under three different shot peening intensities. Cyclic tests for two load magnitudes were performed for 1, 2, 10, 1000 and 10000 cycles. Residual stresses, microhardness and the cold work percentage were measured at initial state and after each loading cycle for the three shot peening intensities and for the two loads. The study revealed that most of the drop in the residual stress, microhardness and cold work happened in the first cycle are dependent on the applied load.

Influence of Different Surface Treatments on Fatigue Life of 7050 Al Alloy

2019 ◽  
Vol 944 ◽  
pp. 142-148 ◽  
Author(s):  
Nan Li ◽  
Hai Tao Li ◽  
Jing Yi Zhou ◽  
Hong Tao Liu ◽  
Chang Kui Liu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Fracture Surface ◽  
Surface Morphology ◽  
Surface Analysis ◽  
Shot Peening ◽  
Surface Treatments ◽  
Al Alloy ◽  
Stress Measurements ◽  
Fracture Surface Analysis

The fatigue life of 7050 Al alloy samples after different surface treatments, i.e., as-machined, anodizing, shot peening, and shot peening followed by anodizing, had been tested. The shot peening treatment specimens presented the longest average fatigue life. The fatigue life of anodizing treatment specimens decreased by 69.3% and 78.8% at 215 MPa and 260 MPa stress levels than as-machined ones. Introducing the shot peening treatment before anodizing can increase the fatigue life by 220% / 296.9% at 215 MPa/260 Mpa than that only treated by anodizing. The effect of the surface treatments on the fatigue life were studied by performing surface morphology investigation, residual stress measurements and fracture surface analysis.

scholarly journals Stress Relaxation Behavior of Cavitation-Processed Cr–Mo Steel and Ni–Cr–Mo Steel

2019 ◽  
Vol 9 (2) ◽  
pp. 299
Author(s):  
Kumiko Tanaka ◽  
Daichi Shimonishi ◽  
Daisuke Nakagawa ◽  
Masataka Ijiri ◽  
Toshihiko Yoshimura
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
High Pressures ◽  
Relaxation Behavior ◽  
Material Surface ◽  
Stress Relaxation Behavior ◽  
Gas Atmosphere ◽  
New Processing

Cr–Mo steel and Ni–Cr–Mo steel have higher strength and hardness than carbon steel, and they are occasionally used in harsh environments where high temperatures and high pressures are simultaneously applied in an oxidizing gas atmosphere. In general, in order to improve the fatigue strength of a material, it is important to impart compressive residual stress to the material surface to improve crack resistance and corrosion resistance. Conventionally, the most famous technique for imparting compressive residual stress by surface modification of a material is shot peening processing. However, in shot peening processing, there is concern that particles adhere to the surface of the material or the surface of the material becomes rough. Therefore, in this study high temperature and high-pressure cavitation was applied and the material surface was processed at the time of collapse. A theoretical and experimental study on a new processing method giving compressive residual stress was carried out. In the present study, we will report stress relaxation behavior due to the heat of cavitation in processed Cr–Mo steel and Ni–Cr–Mo steel.

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.

Effect of Different Shot Peening Treatments on Fatigue Life in Ti Alloy

2018 ◽  
Vol 941 ◽  
pp. 908-913
Author(s):  
Yasunori Harada ◽  
Yuto Saeki ◽  
Katsuhiko Takahashi
Keyword(s):  
Titanium Alloy ◽  
Fatigue Life ◽  
Shot Peening ◽  
Work Hardening ◽  
Cast Steel ◽  
Average Diameter ◽  
Hardened Layer ◽  
Material Surface ◽  
Ultrasonic Shot Peening ◽  
The Media

The effects of peening conditions on the surface characteristics and fatigue life of titanium alloy was investigated using microshot peening, ultrasonic shot peening, and multiple shot peening. The use of microshot peening technology with minute media has become more widespread in consideration of the reduction of the notch effect in the material surface. The ultrasonic shot peening that uses media of several millimeters in size with ultrasonic vibration has attracted attention as a means to reduce the surface roughness. In the present study, an air-type and an ultrasonic type machine were used. In the microshot peening process, the media used was high-carbon cast steel and the hard powder, with an average diameter of 0.1 mm. The workpiece was commercial titanium alloy Ti-6Al-4V. In the microshot peening (MSP), work hardening was evident to the depth of approximately 0.3 mm from the surface. This depth was approximately three times the diameter of the media. However, the influence of the peening time on the hardness distribution was not great. In the ultrasonic shot peening (USP), work hardening was deeper in the material. This is because the diameter of the media used for ultrasonic machining was large. On the other hand, in the combined shot peening (CSP), a degree of hardness was higher at the top surface. However, the hardness patterns and values were pretty much identical to ultrasonic shot peening. The fatigue limit was thought to be greater in the microshot peening experiment because the work-hardened layer was formed near the workpiece surface.

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