scholarly journals Influence of Residual Stress on Fatigue Design of AISI 304 Stainless Steel

2011 ◽  
Vol 7 (2) ◽  
pp. 44 ◽  
Author(s):  
L. Singh ◽  
R.A. Khan ◽  
M.L. Aggarwal
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Fatigue Strength ◽  
Stress Field ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Residual Stress Field ◽  
Aisi 304 ◽  
Fatigue Design

 Austenitic stainless steel cannot be hardened by any form of heat treatment, in fact, quenching from 10000C merely softens them. They are usually cold worked to increase the hardness. Shot peening is a cold working process that changes micro-structure as well as residual stress in the surface layer. In the present work, the compressive residual stress and fatigue strength of AISI 304 austenitic stainless steel have been evaluated at various shot peening conditions. The improvement in various mechanical properties such as hardness, damping factors and fatigue strength was noticed. Compressive residual stress induced by shot peening varies with cyclic loading due to relaxation of compressive residual stress field. The consideration of relaxed compressive residual stress field instead of original compressive residual stress field provides reliable fatigue design of components. In this paper, the exact reductions in weight and control of mechanical properties due to shot peening process are discussed. 

Characterisation of the Residual Stress Field and Mechanical Properties of a Narrow-Gap Girth-Welded Stainless Steel Pipe and Subsequent Application to a Numerical Model

2011 ◽  
Author(s):  
Robert J. A. McCluskey ◽  
Andrew H. Sherry ◽  
Martin R. Goldthorpe
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Stress Field ◽  
Steel Pipe ◽  
Primary Circuit ◽  
Narrow Gap ◽  
Residual Stress Field ◽  
Butt Weld ◽  
Stainless Steel Pipe

Girth-butt welds are used to join sections of stainless steel pipe in the primary circuit of Pressurised Water Reactors. The welding process creates residual stress fields across the weldment, which can contribute to the crack driving force when a defect is present. Assessment procedures account for such defects, enabling safety justifications to be made for continued operation of nuclear power plant. Such procedures require the size and nature of the residual stress field to be determined in order to make reliable structural integrity assessments. This paper describes the investigation of the residual stress field and fracture behaviour of a recently developed narrow-gap 304-stainless steel girth-butt weld in a primary circuit pipe. Two residual stress measurement techniques, Neutron Diffraction (ND) and incremental Deep Hole Drilling (iDHD), were used to measure the original residual stress field in the pipe weld. A second pipe weld specimen was used to fabricate tensile and fracture toughness specimens from which the mechanical properties of the weld material were determined. The residual stress and mechanical test data were used to develop numerical models of the pipe weld containing a postulated circumferential defect under an applied axial load. The numerical simulation results were applied within a failure assessment diagram, comparing different interaction parameters on the prediction of component failure load.

scholarly journals Relationship between Damping Factor and Compressive Residual Stress for Shot-Peened Austenitic Stainless Steel

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Lakhwinder Singh ◽  
R. A. Khan ◽  
M. L. Aggarwal
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Film Surface ◽  
Damping Factor ◽  
Thin Film Surface ◽  
Deformed Layer

The mechanical properties of austenitic stainless steel are rarely improved by heat treatment. Shot peening is a well-known cold working process that affects thin surface of materials. By controlling the shot peening intensity and shot size, the variable mechanical properties film thickness was obtained from 0.05 mm to 0.5 mm. The damping factor and compressive residual stress are determined experimentally and forming a relation between them. It was found that damping factor in thin film surface increases with depth of deformed layer. An investigation was carried out, and it was found that the increase in damping factor was due to introduction of compressive residual stress and increased hardness due to shot peening. The paper discusses a model of changing damping properties with compressive residual stress and depth of deformed layer of austenitic stainless steel.

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.

scholarly journals Effect of Micro-Shot Peening on the Fatigue Performance of AISI 304 Stainless Steel

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1408
Author(s):  
Yu-Hsuan Chung ◽  
Tai-Cheng Chen ◽  
Hung-Bin Lee ◽  
Leu-Wen Tsay
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Fatigue Strength ◽  
Strain Hardening ◽  
Fatigue Resistance ◽  
Shot Peening ◽  
304 Stainless Steel ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304

The effects of micro-shot peening on the rotating bending fatigue resistance of AISI 304 stainless steel (SS) were investigated in this study. The strain-hardening, surface roughness and induced residual stress were inspected and correlated with fatigue strength. Micro-shot peening caused intense strain-hardening, phase transformation and residual stress but was also accompanied by a minor increase in surface roughness. A nanograined structure, which was advantageous to fatigue resistance, was observed in the severe shot-peened layer. The absence of microcracks, minor increase in surface roughness, nanograined structure and induced high compressive residual stress in the shot-peened layer were responsible for the improved fatigue strength of AISI 304 SS.

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.

The Numerical Optimization of Laser Shot Peening Parameters Based on Response Surface Analysis

2011 ◽  
Vol 464 ◽  
pp. 443-447
Author(s):  
Su Qing Jiang ◽  
Jian Hua Wu ◽  
Hong Guang Xu ◽  
Jian Zhong Zhou
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Response Surface ◽  
Surface Analysis ◽  
Process Parameters ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Response Surface Analysis ◽  
Residual Stress Field ◽  
Laser Process

Residual stress field induced by laser shot peening (LSP) was simulated using Box-Behnken experimental design. Compressive residual stress field intensity (S) was introduced to estimate the effect of compressive residual stress field on fatigue performance. The effect of laser process parameters (such as laser shock wave peak pressure, spot diameter and peening number) on S was analyzed by response surface analysis (RSA), quadratic regression predicting model for S was established, and the rationality of that was verified. Finally, the optimal combination of laser process parameters oriented to anti-fatigue manufacture was optimized. The results indicated statistical analysis results agreed well with those of simulation, RSA for parameter optimization of LSP is feasible.

Influence of Laser Parameters on Residual Stress Field of AISI 304 Stainless Steel Induced by Laser Peening: A Finite Element Analysis

2006 ◽  
Author(s):  
Xiang Ling ◽  
Weiwei Peng
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Stress Field ◽  
Stress Corrosion ◽  
Compressive Stress ◽  
304 Stainless Steel ◽  
Laser Peening ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304

The present paper established a non-linear elastic-plastic finite element method to predict the residual compressive stress distribution induced by Laser Peening (LP) in the AISI 304 stainless steel. The two dimensional FEA model considered the dynamic material properties at high strain rate (106/s) and the evaluation of loading conditions. Effects of laser power density, laser spot size, laser pulse duration, multiple LP processes and one/two-sided peening on the compressive stress field in the stainless steel were evaluated for the purpose of optimizing the process. Numerical results have a good agreement with the measurement values by X-ray diffraction method and also show that the magnitude of compressive stress induced by laser peening is greater than the tensile welding residual stress. So, laser peening is an effective method for protecting weldments against stress corrosion crack. The above results provide the basis for studying the mechanism on prevention of stress corrosion cracking in weld joint of type 304 stainless steel by laser peening.

Numerical Simulation of Residual Stress Field Induced by Ultrasonic Shot Peening

2008 ◽  
Vol 373-374 ◽  
pp. 832-835 ◽  
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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