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[en] A procedure and device for the shot peening of the outer surface of pin- or U-shaped tubes intended for heat exchangers are presented. Said procedure is intended for a uniform processing of the rectilinear legs and the curved portion of each tube to be obtained
[fr]On presente un procede et un dispositif pour le traitement par grenaillage de la surface externe de tubes en epingle, ou en U destines aux echangeurs de chaleur. Ledit procede a pour but de realiser un traitement uniforme des branches rectilignes et de la partie courbee de chaque tube
[en] In this study, the influence of shot peening on the corrosion was investigated on spring steel immersed in 3.5% NaCl. The immersion test was performed on the two kinds of specimens. Corrosion potential, polarization curve, residual stress and etc. were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated. In case of corrosion potential, shot peened specimen shows more activated negative direction as compared with parent metal. Surface of specimen, which is treated with the shot peened, is placed as more activated state against inner base metal. It can cause the anti-corrosion effect on the base metal
[en] There are various methods available for the on-site decontamination of removable equipment in Switzerland: a shot peening glass beads method, using a mixture of demineralized water and glass beads within a closed box; high pressure water jet method; wet cleaning methods, using washing basins of different dimensions, detergent and brushes. The manuel cleaning is limited to a few cases, where the special form or the dimensions of the equipment do not allow the application of the glass bead method. Examples of the first two methods are discussed here. These methods have been in use at the nuclear power plant Muehleberg, which is a General Electric Mk I boiling water reactor of 306MWe (net) power and which has been in commercial operation since October 1972
[en] One of the widely used powder metal materials in automotive industry, which is copper steel FC 0205 (Fe + 2% Cu + 0.5% C), was used in this study. The pressed samples has been prepared at the compression pressure of 680 MPa and sintered in conventional furnace at 1120 .deg. C for 30 minutes. The samples with 7 Mg/m"3 densities were used as fatigue and shot peening processes. Shot peening were applied with 20A and 32A and the others were not peened. Plasma nitrocarburizing process was performed at 555 .deg. C for 2 hours under 600-900 Pa pressure. Fatigue tests were conducted at room temperature on a rotating bending type fatigue test device. It was determined that shot peening should be used where increased fatigue strength is needed, and plasma nitrocarburizing should be preferred where surface hardness is required, and plasma nitrocarburizing after shot peening process is much more useful.
[en] Work under this research project covered tests with the quenched and tempered steel 42 CrMo 4 to which one- and two-stage tension-compression fatigue stresses were applied with varying mean loads, under conditions of nominal stress and total strain control. Shot peening was used to induce various microstructural conditions in the material at the surface and near below. Softening in the material was observed to be a continuous process, and the steel showed no stabilised, cyclic deformation behaviour. The cyclic stress-strain curve measured with equal stress amplitudes and total strain control applied shows higher plastic strain amplitudes than that measured with nominal stresses. The fatigue behaviour under two-stage loading depends on the chosen sequence of loads applied, the testing periods, and the overall testing procedure, so that there is no way of deriving data for two-stage testing procedures from single-stage test results. (orig.)
[de]Im Rahmen des Forschungsvorhabens wurden an dem Verguetungsstahl 42 CrMo 4 ein-und zweistufige nennspannungs- und totaldehnungskontrollierte Zug-Druck-Wechselverformungsexperimente mit unterschiedlichen Mittelbeanspruchungen durchgefuehrt. Durch Kugelstrahlbehandlungen wurde der Zustand oberflaechennaher Werkstoffbereiche gezielt beeinflusst. Der untersuchte Verguetungszustand des 42 CrMo 4 entfestigt stetig und weist kein stabilisiertes zyklisches Verformungsverhalten auf. Die zyklische Spannungs-Dehnungs-Kurve zeigt bei gleichen Spannungsamplituden unter Totaldehnungskontrolle groessere plastische Dehnungsamplituden als unter Nennspannungskontrolle. Das Wechselverformungsverhalten bei zweistufiger Beanspruchung ist von der Beanspruchungsreihenfolge, den Blocklaengen sowie der Versuchsfuehrung abhaengig und kann deshalb nicht direkt aus Einstufenversuchen abgeleitet werden. (orig.)
[en] In this study, the improvement of fatigue life in Al7075-T6 specimen with a circular hole-notch was investigated. Optimum-peening intensity was applied to the specimen and the fatigue test was accomplished at the room and high temperature environment. A circular hole-notch with the diameter d = 0.6mm and the depth h = 0.6mm was artificially made on the surface of the center of the specimen. The optimum-peening intensity was 0.341mmA. Fatigue test was performed by 4-point rotary bending, and applied stress was 260MPa. The fatigue lives of shot peened specimens were about 5 times, 8 times, and 4 times longer than unpeened specimens under the room temperature, the high temperature of 100 .deg. C, and the high temperature of 200 .deg. C, respectively. From the experimental results, the improvement of fatigue life of Al7075-T6 specimens with a circular hole-notch was confirmed by shot peening. It is expected the shot peening effect on notched structures in various industries will be excellent.
[en] Residual stresses may lead to micro scaling of pump reduction gear teeth. Stresses distribution improvements by shot-peening are presented with effects of tensile stresses coming from the rectification process. (A.B.). 5 refs., 2 figs., 2 tabs
[en] Hard little particles peening a radioactively contaminated metal surface are decontaminated by interrupting the circulation of the particles when their contamination exceeds a threshold. The particles are put in a decontamination vessel and treated by a reducing agent before rinsing with water and drying by air
[fr]On interrompt la circulation des particules dans l'installation de martelage lorsque la contamination de ces particules atteint un seuil predetermine, on preleve les particules contaminees et on les introduit dans un recipient de decontamination, on met en circulation dans l'installation de martelage une nouvelle charge de particules non contaminees pour redemarrer l'operation de martelage et, pendant que l'operation de martelage se deroule, on realise la decontamination des particules dans le recipient par lavage avec un reactif reducteur. Le dispositif comporte de preference un tambour de lavage rotatif
[en] The shot peening process is most often used to improve fatigue properties of metal parts. The single most critical parameter of the shot peening process is the shot ball itself. Without the correct quality media, all other shot peening parameters are extraneous and the desired fatigue improvement and consistency of improvement will not be achieved. shot peening involves modifications of the surface and subsurface condition of a material that can be described by the change of the residual stresses, the hardness, and the surface roughness. This paper presents the shot peening to optimize the shot ball parameters. The effect of shot peening parameter on the surface roughness, surface hardness and residual stress are investigated
[en] Laser peening (LP) induces high magnitude compressive residual stresses in a small region of a component. The compressive residual stresses cause plastic deformation that is resistant to fatigue fracture. Fatigue cracks are generally nucleated at critical areas, and LP is applied for those regions so as to delay the crack initiation. Many critical regions are located on the edge of the curved portion of structures because of stress concentration effects. Several investigations that are available for straight components may not give meaningful guidelines for peening curved components. Therefore, in this paper, we investigate residual stress behaviors induced by LP along the edge of curved models. Three curved models that have different curvatures are investigated for peening performance. Two types of peening configurations, which are simultaneous corner shot and sequential corner shots, are considered in order to obtain compressive residual stresses along an edge. LP simulations of multiple shots are performed to identify overlapping effects on the edge portion of a curved model. In addition, the uncertainty calculation of residual stress induced by LP considering laser pulse duration is performed