Publication

Abstract : Water jet peening has gained attention as a potential surface treatment process for improving the fatigue life of a component. The tensile residual stress in the component initiates the stress corrosion cracking and reduces its fatigue life. The mitigation of this tensile residual stress can be effectively achieved by water jet peening process due to its resistance to corrosion, flexibility in treating complex areas and capability to maintain the eco-friendly environment. In the present work, the AISI 304 plates were treated with pulsating water jet (actuator frequency f = 20.19 Hz) at the pressure of p = 20 MPa with traverse speed of v = 0.5 mm/s and v = 2.5 mm/s using two different types of nozzles; flat nozzle of diameter d = 1 mm (HAMMELMANN) and circular nozzle of diameter d = 1.9 mm (STONEAGE). The microstructural analysis of the treated and untreated region was conducted to analyse the effect of traverse speed and the type of nozzle on the erosion process. The study revealed that more erosion occurs at lower traverse speed; however, fewer surface depressions were observed in the case of flat nozzles. The X-ray diffraction technique was also used to analyse the effect of traverse speed and the type of nozzle on the residual stress of the samples. In addition to this, the acoustic emission during the ongoing process was monitored using LabView 2012 SP1 f5 ver. 12.0.1. The results indicate that acoustically monitored pulsating water jet peening process can be used as tool for the controlled local treatment process arising from the impact of the pulsed water jet on the surface of sample.