Surface profiling of low-carbon steel with supersonic waterjets

In the paper, the authors investigate the capability of high-speed watejets with velocities up to 700 m/s for the surface preparation of low-carbon st eel. The problems associated with grit-blasting are reviewed, including gri t contamination and the corresponding adhesion problems. Surface quality fe atures of waterjetted surfaces are investigated; this includes average surf ace roughness, Rockwell hardness, surface microstructure, and wettability. The influence of several process parameters, such as jet velocity, jet impa ct energy and exposure time on process efficiency and surface quality are a lso investigated. It is found that waterjetting is capable of generating a high surface roughness. A general relationship between roughness and wettab ility of the generated surfaces is found; however, this is true only if a c ertain exposure time is exceeded. Waterjetting causes a notable increase in the Rockwell hardness. The higher the specific material removal, the highe r the hardness. The specific material removal is linearly related to the ki netic energy of the impacting waterjet. (C) 2001 Elsevier Science B.V. All rights reserved.