Effect of residual stresses on fatigue strength of severely surface deformed steels by shot peening

2009 ◽  
Vol 24 (S1) ◽  
pp. S37-S40 ◽  
Author(s):  
Yoshiaki Akiniwa ◽  
Hidehiko Kimura ◽  
Takeo Sasaki

The compressive stress distribution below the specimen surface of severely surface deformed steels by shot peening was investigated by using laboratory X-rays and high-energy X-rays from a synchrotron radiation source, SPring-8 in the Japan Synchrotron Radiation Research Institute. Medium carbon steel plates were heat treated in two different conditions. The Vickers hardness of materials A and B after heat treatment is 408 and 617 HV, respectively. The specimens were shot peened with fine cast iron particles of the size of 50 μm. The coverage was selected to be 5000%. For the synchrotron radiation, by using the monochromatic X-ray beam with several energy levels, the stress values at the arbitrary penetration depth were measured by the constant penetration depth method. The shot-peened specimens were fatigued under four-point bending. The improvement of fatigue strength of material A was not so large because of large surface roughness. On the other hand, for material B, the surface roughness was smaller and the fatigue strength was higher than that of ground specimens.

2008 ◽  
Vol 571-572 ◽  
pp. 15-20 ◽  
Author(s):  
Yoshiaki Akiniwa ◽  
Hidehiko Kimura

The compressive stress distribution below the specimen surface of a nanocrystalline medium carbon steel was investigated nondestructively by using high-energy X-rays from a synchrotron radiation source, SPring-8 (Super Photon ring-8 GeV) in the Japan Synchrotron Radiation Research Institute. A medium carbon steel plate was shot-peened with fine cast iron particles of the size of 50 μm. By using the monochromatic X-ray beam with three energy levels of 10, 30 and 72 keV, the stress values at the arbitrary depth were measured by the constant penetration depth method. The stress was calculated from the slope of the sin2ψ diagram. Measured stress corresponds to the weighted average associated with the attenuation of the X-rays in the material. The real stress distribution was estimated by using the optimization technique. The stress distribution was assumed by the third order polynomial in the near surface layer and the second order polynomial. The coefficients of the polynomials were determined by the conjugate gradient iteration. The predicted stress distribution agreed well with that measured by the conventional surface removal method.


2009 ◽  
Vol 614 ◽  
pp. 163-168 ◽  
Author(s):  
Seiki Sakoda ◽  
Katsuji Tosha

This paper describes the influence of shot peening on of the peened surface and fatigue strength. Shot peening was performed by a wet blasting machine with a wide nozzle. At first, influences of particle size and geometry on characteristic values such as surface roughness, residual stress, FWHM, and Vickers hardness were examined, and then fatigue strength was studied on the peened materials. The material is a medium carbon steel (C:0.45%, 180HV) and the peening particles are alumina and glass beads. The following results are shown in this paper: (1) On the specimen a width of 83% of the wide nozzle is peened uniformly judging from chatterings of FWHM, compressive residual stresses and surface roughness. (2) Surface roughness, compression residual stress, FWHM and the maximum hardness increase with increasing particle size except for the case of 57μm particles; the maximum values are 0.52μm, 390MPa, 2.15deg, 205.6HV respectively. (3) Fatigue strength is improved using alumina and glass beads by 20% and 15%. (4) The peening process using a wide nozzle can effectively improve fatigue strength.


2020 ◽  
Vol 142 ◽  
pp. 106004 ◽  
Author(s):  
Vicente Martín ◽  
Jesús Vázquez ◽  
Carlos Navarro ◽  
Jaime Domínguez

1991 ◽  
Vol 35 (B) ◽  
pp. 995-1000
Author(s):  
J.V. Gilfrich ◽  
E.F. Skelton ◽  
S.B. Qadri ◽  
N.E. Moulton ◽  
D.J. Nagel ◽  
...  

AbstractIt has been well established over recent years that synchrotron radiation possesses some unique features as a source of primary x-rays for x-ray fluorescence analysis. Advantage has been taken of the high intensity emanating from the bending magnets of storage rings to develop x-ray microprobes utilizing apertures or focussing optics, or both, to provide a beam spot at the specimen of the order of micrometers. The use of insertion devices wigglers and undulatora, can further increase the available intensity, especially for the high energy photons. Beam Line X-17C at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory, accepts the unmodified continuum radiation from a superconducting wiggler in the storage ring. Some initial XRF measurements have been made on this beam line using apertures in the 10 to 100 micrometer range. The fluorescent radiation was measured by an intrinsic Ge detector having an energy resolution of 300 eV at 15 kev, and located at 90° to the incident beam in the plane of the electron orbit. In samples containing many elements, detection limits of a few ppm were achieved with 100 μm beams.


Hyomen Kagaku ◽  
2005 ◽  
Vol 26 (9) ◽  
pp. 524-531 ◽  
Author(s):  
Hideyuki YASUFUKU ◽  
Hideki YOSHIKAWA ◽  
Masahiro KIMURA ◽  
Sei FUKUSHIMA

2013 ◽  
Vol 662 ◽  
pp. 449-452 ◽  
Author(s):  
Wei Ran Duan ◽  
Yi Fan Dai ◽  
Yong Shu ◽  
Ian Sherrington

Surface roughness plays an important role on optical performances for optics in high-energy laser systems. In this study, optical surface of fused silica were polished by the Magnetorheological Finishing (MRF) processes. The polishing factors in term of Magnetorheological fluid (MR fluid) flow rate, polishing wheel rotational speed, electromagnet current, and polishing ribbon penetration depth, were carried out using an self-developed MRF machine to determine optimum conditions for surface roughness. The settings of the MRF processing parameters were determined by using Taguchi’s experimental design method. Taguchi’s orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) were employed to investigate the optimal processing parameters. The experimental results indicate that surface with smaller roughness could be machined under the conditions with slower rotating speed and higher flow rate and current, and nearly independent of penetration depth.


2018 ◽  
Vol 51 (3) ◽  
pp. 732-745 ◽  
Author(s):  
Marianna Marciszko ◽  
Andrzej Baczmański ◽  
Manuela Klaus ◽  
Christoph Genzel ◽  
Adrian Oponowicz ◽  
...  

The main focus of the presented work was the investigation of structure and residual stress gradients in the near-surface region of materials studied by X-ray diffraction. The multireflection method was used to measure depth-dependent stress variation in near-surface layers of a Ti sample (grade 2) subjected to different mechanical treatments. First, the multireflection grazing incidence diffraction method was applied on a classical diffractometer with Cu Kα radiation. The applicability of the method was then extended by using a white synchrotron beam during an energy dispersive (ED) diffraction experiment. An advantage of this method was the possibility of using not only more than one reflection but also different wavelengths of radiation. This approach was successfully applied to analysis of data obtained in the ED experiment. There was good agreement between the measurements performed using synchrotron radiation and those with Cu Kα radiation on the classical diffractometer. A great advantage of high-energy synchrotron radiation was the possibility to measure stresses as well as thea0parameter andc0/a0ratio for much larger depths in comparison with laboratory X-rays.


MRS Bulletin ◽  
2001 ◽  
Vol 26 (4) ◽  
pp. 337-340 ◽  
Author(s):  
Jill Hruby

LIGA, an acronym for the German words for lithography, electroplating, and molding, is a technique used to produce micro-electromechanical systems (MEMS) made from metals, ceramics, or plastics. The LIGA process utilizes x-ray synchrotron radiation as a lithographic light source. Highly collimated, high-energy x-rays from the synchrotron impinge on a patterned mask in proximity to an x-ray-sensitive photoresist, typically poly(methyl methacrylate) (PMMA).


2002 ◽  
Vol 19 (1) ◽  
pp. 73-76
Author(s):  
Nikita Salvi ◽  
Mat J. Page ◽  
Jason A. Stevens ◽  
Keith O. Mason ◽  
Kinwah Wu

AbstractIII Zw2 was observed with XMM-Newton in July 2000. Its X-ray spectrum can be described by a power law of photon index Γ≈1.7 with a Gaussian line at 6.7 KeV. There is no significant evidence of intrinsic absorption within the source or of a soft X-ray excess. Multi-wavelength light curves over a period of 25 years show related variations from the radio to X-rays. We interpret the radio to optical emission as synchrotron radiation, self-absorbed in the radio/millimetre region, and the X-rays as mainly due to Compton up-scattering of low energy photons by the population of high energy electrons that give rise to the synchrotron radiation.


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