Shot peening in a novel centrifugal air blast reactor

Abstract

A novel reactor to synthesise a thick nanocrystalline (NC) layer on metallic surface by shot peening is presented. In this cylindrical reactor, air enters inside the reactor tangentially and propels shots on specimen surface for peening. The air then leaves the reactor after multiple rotations. Air vortex and very high turbulence inside the reactor dissipate the heat generated during shot peening and thus avoids dynamic recovery. Experiments were conducted on samples of austenitic stainless steel with different shot velocities. Characterisation of shot peened surfaces showed that thick layers with NC/nano-twinned structure were developed under all peening conditions used in the experiments. Microstrain in the lattice, dislocation density and volume fraction of strain-induced martensite observed to increase with rise in shot velocity. Consistent reduction in grain size and enhancement in dislocation density with increase in strain, indicate that no dynamic recovery occurred during the shot peening process in the reactor.

Effect of Shot Peening in Different Shot Distance and Shot Angle on Surface Morphology, Surface Roughness and Surface Hardness of 316L Biomaterial

“…It could be realized the effect on the decreasing of grain diameter [18]. Consistent reduction in grain size and enhancement in dislocation density with increase in strain, indicate that no dynamic recovery occurred during the shot peening process [19]. The references give the support statement that the shot peening is an appropriate mechanical surface treatment to be applied on surface of 316L to achieve the objective of this research to investigate the effect of shot peening in relation with shot distance and shot angle on surface morphology, surface roughness, and surface hardness of 316L biomaterial.…”

“…The changes in shot angle also give an effect, the larger the shot angle the smoother the shape and size of the grain as shown in figure 5. According to Ranaware and Rathod [19], reduction in grain size and enhancement in dislocation density with increase in strain, indicate that no dynamic recovery occurred during the shot peening process. This grain refined will also increase the hardness properties of the material, due to the increasingly denser structure on the surface of the specimen.…”

Determination of the optimal coverage for heavy-duty-axle gears in shot peening

“…Hence, it is revealed that with the increase of coverage, grain size at the topmost surface decreases, whereas FWHM becomes wider. This is due to plastic deformation occurs on the gear surface layer induced by continuous impacts of shot streams, which leads to grain refinement and lattice distortion [53].…”

Editorial: special issue on shot peening

“…The improvements resulting from the SP process on a variety of base materials, ranging from solid metals to alloys are discussed. These materials include austenitic stainless steel [4], AISI 1018 [1] and 4340 steel [5], S355 J2 structural steel [3], X65 steel [2], precipitation hardened ultrafine-grained copper alloy [6], austempered ductile iron [7] and Vitreloy 105 bulk metallic glass [8]. Yin et al [1] perform mathematical modelling and simulations of the kinetics of the process to predict the resulting surface topography of peened samples.…”