Publication

Abstract : In the present work a detailed effect of pulsating water jet treatmentwith the variation of standoff distance on the flat austenitic stainless steel surfacehas been studied. During the experimentation, at a traverse speed of 30 mm/saccidently the change in frequency was encountered in the repeated test (undersame treatment condition) which has been reported in this work. The frequencywas changed from f= 20.11 kHz to f= 20.27 kHz during the treatment processat the pressure of p= 70 MPa with variation in standoff distance was increasedfrom z= 5 mm up to z= 101 mm (with step distance of 2 mm between suc-cessive standoff distance). The change in microstructural topography of thetreated surface under the above-mentioned conditions was observed usingscanning electron microscopy (SEM). The strengthening mechanism on thesurface and sub-surface region due to the plastic deformation phenomenoncaused by the impact of the pulsating jet was evaluated by Vickers micro-hardness test. The micro hardness test was conducted along the depth of thetreated region to analyze the effects in the sub-surface layers. Also, the erosionstages at different standoff distance was evaluated by scanning the surface byoptical MicroProf FRT profilometer in order to analyze the nature of erosionphenomenon with the variation of standoff distance and frequency during thetreatment process. The results obtained indicates that the change in frequency ofthe pulsations and the variation in standoff distance has a significant impact onthe surface integrity of the treated material. As compare to the untreated surfacethe hardness of the treated surface was increased up to a certain depth and thehigher frequency of pulsations has shown better improvement in the hardnessvalues. The above observations elaborated the effect of an important parameterfrequency and standoff distance for better and effective utilization of the tech-nology for the surface treatment application