An experimental study of residual stress induced by ultrasonic shot peening

This paper presents a 3D model that simulates an ultrasonic shot peening (USP) operation, using realistic process parameters and peening setups (part and chamber geometries). By simulating the shot dynamics (shot trajectories and impacts), statistical and spatial data are obtained for the peened component, i.e. surface coverage and coverage rate, impact speeds and angles, dissipated energy... This data can then be used for i) optimizing the design of peening chambers and process parameters and ii) predicting the residual stress and displacement fields induced by USP in the peened component. In fact, data from the 3D model can be used as initial data in existing residual stress prediction models. A chaining methodology was developed for this purpose and allows linking the choice of process parameters and USP setup to the induced residual stress displacement fields.

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Numerical Simulation of Residual Stress Field Induced by Ultrasonic Shot Peening

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.373-374.832 ◽

2008 ◽

Vol 373-374 ◽

pp. 832-835 ◽

Cited By ~ 1

Author(s):

Gang Ma ◽

Xiang Ling ◽

Yuan Song Zeng

Keyword(s):

Residual Stress ◽

Finite Element ◽

Stainless Steel ◽

Shot Peening ◽

Compressive Residual Stress ◽

Diffraction Method ◽

Residual Tensile Stress ◽

Finite Element Software ◽

Ultrasonic Shot Peening ◽

Stress Layer

A 3D finite element model is established to simulate the ultrasonic shot peening process by using a finite element software ABAQUS. The residual stress distribution of the AISI 304 stainless steel induced by ultrasonic shot peening (USP) is predicted by finite element analysis. Ultrasonic shot peening (USP) process can cause a compressive residual stress layer on the surface of the material. During the simulation, many factors, e.g., ultrasonic shot peening duration, initial residual stress, hourglass, etc., are taken into consideration for the purpose of optimizing the process. The simulation results show that ultrasonic shot peening can produce a compressive residual stress layer on the surface of the material even if there is initial residual tensile stress (250MPa) and the longer peening duration. The residual stress of simulation were compared with the experiment data which were obtained under the same ultrasonic shot peening parameters and have a good agreement with the measurement values by X-ray diffraction method. In conclusion, ultrasonic shot peening is an effective method for protecting weldments against stress corrosion cracking by introducing the compressive residual stress layer into the surface of stainless steel.

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Experimental Study on Ultrasonic Shot Peening Forming and Surface Properties of AALY12

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1094.339 ◽

2015 ◽

Vol 1094 ◽

pp. 339-342

Author(s):

Chao Xun Liu ◽

Shi Hong Lu ◽

Wei Miao ◽

Pan Feng Song ◽

Tian Rui Wu

Keyword(s):

Experimental Study ◽

Surface Roughness ◽

Electric Current ◽

Shot Peening ◽

Processing Time ◽

Radius Of Curvature ◽

Micro Hardness ◽

Current Time ◽

Ultrasonic Shot Peening ◽

The Relationship

Ultrasonic shot peening (USP) on AALY12 sheet was studied. Several parameters (arc heights, surface roughness, surface topography and micro hardness) with different USP process parameters were measured. The research proposes that radius of curvature of shot peened sheet increases with time and electric current decreasing, while increases with pin diameter increasing, and radius of curvature reaches a saturation level after a specific processing time and electric current. An empirical model of the relationship between radius of curvature and pin diameter, electric current, time was also obtained. The research shows that the increment of surface and vertical micro hardness of material is more obvious with longer time and higher value of electric current, which can be up to 20% and 28% respectively.

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Development of Ultrasonic Shot Peening Technique for Reactor Components to Improve Structural Integrity Against Stress Corrosion Cracking

Volume 1: Plant Operations, Maintenance, Engineering, Modifications and Life Cycle; Component Reliability and Materials Issues; Next Generation Systems ◽

10.1115/icone17-75500 ◽

2009 ◽

Cited By ~ 1

Author(s):

Shohei Kawano ◽

Ayaka Kawagishi ◽

Nobuichi Suezono ◽

Kenichi Ueno ◽

Ken Okuda ◽

...

Keyword(s):

Residual Stress ◽

Stainless Steel ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Shot Peening ◽

Structural Integrity ◽

Weld Line ◽

Corrosion Cracking ◽

Experimental Result ◽

Ultrasonic Shot Peening

The ultrasonic shot peening (USP) technique has been developed for boiling water reactor (BWR) components as a countermeasure against stress corrosion cracking. The effects on residual stress of USP for type 316L stainless steel and alloy 600 were evaluated. Compressive residual stress layer of 0.5 mm from the surface were formed on the specimens after USP using stainless steel ball with a diameter of 3 mm. Cross-sectional hardness measurement revealed that the increase of hardness due to USP is not significant compared with shot peening (SP). The FEM calculation showed the plastic strain induced by the impacts of 3 φ shot with 5 m/s is lower than those of 0.6 φ shot with 50 m/s. It suggests USP process suppresses the degree of work hardening in comparison with SP process. Dissimilar weld joint specimens which simulate the material and dimension of the shroud weld line H7 were examined to confirm the applicability of USP. The experimental result reveals that USP technique is applicable to reactor internal components as stress modification process.

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Effect of Ultrasonic Shot Peening on the Fatigue Strength of Stainless Cast Steel ASTM CA6NM for Hydraulic Turbine Runner

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.891-892.649 ◽

2014 ◽

Vol 891-892 ◽

pp. 649-655 ◽

Cited By ~ 2

Author(s):

Jinta Arakawa ◽

Motoki Kakuta ◽

Yoshiichirou Hayashi ◽

Ryota Tanegashima ◽

Hiroyuki Akebono ◽

...

Keyword(s):

Residual Stress ◽

Growth Rate ◽

Fatigue Crack ◽

Fatigue Strength ◽

Crack Growth Rate ◽

Crack Initiation ◽

Shot Peening ◽

Compressive Residual Stress ◽

Cast Steel ◽

Ultrasonic Shot Peening

In this paper, in order to investigate the effect of the ultrasonic shot peening (USP) treatment on fatigue characteristics of the structural materials for hydroelectric facilities, plane bending fatigue tests were carried out using stainless cast steel ASTM CA6NM performed by USP treatment. The fatigue test results showed that the fatigue strength of the USP materials was approximately 60% higher than that of the untreated materials. In order to examine the reason for that, the effect of USP treatment on fatigue crack initiation behavior was evaluated based on the Haigh's diagram. This evaluation implied that increasing the crack initiation resistance associated with high hardness and high compressive residual stress at surface by USP treatment is the major cause for the improvement of fatigue strength. Furthermore, the effect of USP treatment on fatigue crack propagation behavior was also examined by simulating the crack growth rate considering the stress intensity factor at crack tip. Crack propagation simulation results suggested that compressive residual stress leads crack growth rate slow compared with untreated material.

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Role of Ultrasonic Shot Peening in Environmental Hydrogen Embrittlement Behavior of 7075-T6 Alloy

Hydrogen ◽

10.3390/hydrogen2030020 ◽

2021 ◽

Vol 2 (3) ◽

pp. 377-385

Author(s):

Mahdieh Safyari ◽

Masoud Moshtaghi

Keyword(s):

Residual Stress ◽

Hydrogen Embrittlement ◽

Fracture Mode ◽

Shot Peening ◽

Unit Length ◽

Surface Residual Stress ◽

Nitrogen Gas ◽

Ultrasonic Shot Peening ◽

Slow Strain Rate Technique

The effect of ultrasonic shot peening on the environmental hydrogen embrittlement behavior of the 7075-T6 aluminum alloy is investigated. The 7075-T6 tensile specimens were treated by ultrasonic shot peening for 50 s. Surface residual stress and the depth of residual stress under the surface were evaluated using an X-ray diffractometer. Then, the specimens were tensile tested in humid air and dry nitrogen gas by the slow strain rate technique. The results showed that the ultrasonic shot-peened specimen has a superior hydrogen embrittlement resistance. Further, the ultrasonic shot peening changes the fracture mode from an intergranular fracture mode to the transgranular one. It was suggested that ultrasonic shot-peening has two effects on hydrogen embrittlement behavior; the distribution of hydrogen inside the surface layer by introducing dislocations/vacancies as hydrogen traps and reducing the normalized amount of hydrogen trapped per unit length of the grain boundary.

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Analysis of the Impact of a Shot at Low Velocity Using the Finite Element Method. Application to the Ultrasonic Shot-Peening Process

Materials Science Forum ◽

10.4028/www.scientific.net/msf.524-525.337 ◽

2006 ◽

Vol 524-525 ◽

pp. 337-342 ◽

Cited By ~ 1

Author(s):

Florent Cochennec ◽

Emmanuelle Rouhaud ◽

Delphine Retraint ◽

Sébastien Rouquette ◽

Arjen Roos

Keyword(s):

Finite Element Method ◽

Residual Stress ◽

Finite Element ◽

Stress Field ◽

Shot Peening ◽

The Finite Element Method ◽

Residual Stress Field ◽

Low Velocity ◽

Ultrasonic Shot Peening ◽

Element Method

Shot-peening is a surface treatment widely used in the industry to improve fatigue life of mechanical components by introducing compressive residual stresses. Ultrasonic shot-peening is a recent development of this process. While the classical shot-peening process uses pneumatic energy to project the shots, ultrasonic peening uses high-power ultrasounds. This energy source allows the use of larger shots projected at lower velocity as compared to classical shot-peening. This work aims at studying the mechanical response (restitution coefficient, residual stress field) of a surface impacted by a shot at low velocity using the finite element method and experimental analysis. This paper presents the simulation of a single elastic steel shot normally impacting an Aluminum alloy plate considered to exhibit a linear-elastic behavior and non-linear isotropic work hardening characteristics. The numerical simulations are carried out for different impact velocities in order to take into account the heterogeneous shot velocity field observed in an ultrasonic shot-peening chamber. We compare the simulated rebound energy and the indentation profiles obtained for different impact velocities to experimental results. The simulated residual stress field topology shows a strong dependence on the shot velocity. While numerical results obtained at high impact energy agree well with literature results, the residual stress distribution simulated for low impact energies shows a tensile layer below the impacted area. The restitution coefficients and the indentation profiles compare well with the experiments.

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Application of USP to Steam Generator Nozzles

ASME 2011 Pressure Vessels and Piping Conference: Volume 1 ◽

10.1115/pvp2011-57495 ◽

2011 ◽

Author(s):

Norimasa Mori ◽

Takeshi Yamamoto ◽

Masahiro Eto ◽

Marekazu Narita ◽

Jun Fujita ◽

...

Keyword(s):

Residual Stress ◽

Plastic Strain ◽

Tensile Stress ◽

Stress Corrosion ◽

Steam Generator ◽

Shot Peening ◽

Alloy 600 ◽

Inner Surface ◽

Ultrasonic Shot Peening ◽

Collision Force

An effective countermeasure against stress corrosion cracks in pipe welds is to improve the residual stress. A new ultrasonic shot peening (USP) technique for steam generator (SG) nozzles will be introduced as a means to improve the residual stress of SG nozzles with Alloy 600 welds. This method changes the residual stress on the inner surface from tensile stress to compressive stress by applying plastic strain to the surface via the collision force of the shot material during the shot peening. Our group has successfully performed 14 USP operations in actual plants in Japan.

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