Surface Roughness Increasing of 2205 Duplex Stainless Steel Using Ultrasonic Cavitation Process

Abstract

This research discusses an invented and helpful application of the ultrasonic cavitation process to increase the surface roughness of 2205 duplex stainless steel DSS on small scales, which may be desired for special applications. This was achieved by an ultrasonic system corresponding with the ASTM G-32 standard. An invented edit was added to the horn to scan the entire sample surface and generate a homogenous cavitation effect. The cavitation for 60, 90, and 120 second increased the surface roughness about 18, 26, and 22 times, respectively, based on the Three-Dimensional Surface Roughness Profilometer 3DSRP and Scanning Electron Microscopy SEM results. This increase was caused by plastic deformation, which only happens in the cavitation incubation stage. Wavy damages resulting from repeated and multiple collapsing of bubbles were noted using atomic force microscopy AFM. The average values of roughness were about 179, 261, and 221 nm after 60, 90, and 120 sesond of cavitation, respectively, compared with 10.89 nm for the reference sample. Voltage maps on the sample surface using electrostatic force microscopy EFM show the electrostatic force variations according to the surface roughness, where it recorded 3.2, 7.4, and 4.1 Volt after 60, 90, and 120 second of cavitation, respectively, vs 0.033 Volt for the reference sample. It shows a good agreement in the results and means that cavitation is a good tool for increasing the metal’s surface roughness for various purposes.